NLE Foundations of Medical-Surgical Nursing — Homeostasis, Inflammation and Cellular ResponseStudy Notes

Homeostasis is the body's dynamic equilibrium—maintaining a stable internal environment within narrow physiologic limits. This steady state includes temperature (36.5–37.5°C), pH (7.35–7.45), fluid volume, electrolyte concentration, blood glucose (80–120 mg/dL fasting), and oxygen-carbon dioxide balance. The human body achieves homeostasis primarily through negative feedback loops—mechanisms that detect change from a 'set point' and trigger a response that reverses that change, restoring stability. Example: When core body temperature rises above 37.5°C (the set point), thermoreceptors signal the hypothalamus, which activates cooling mechanisms (sweating via sympathetic stimulation, vasodilation). Once temperature returns to normal, the stimulus (high temperature) is removed, and cooling stops. This is a negative feedback loop—the response opposes the initial change. Positive feedback loops are rare in physiology but amplify responses (e.g., labor contractions trigger more contractions; clotting cascade accelerates clot formation). These are self-perpetuating and must have a stopping mechanism or they become pathologic. Homeostatic mechanisms involve three key systems: the nervous system (rapid, precise responses), the endocrine system (slower, sustained effects), and the integumentary and renal systems (temperature and fluid regulation). Failure of homeostatic mechanisms underlies most acute and chronic disease states, making this concept central to understanding pathophysiology in Philippine clinical settings where heat-related illness, infectious diseases, and trauma are common presentations.

Stress is any real or perceived threat to homeostasis—it may be physiologic (trauma, infection, surgery, hemorrhage, pain, temperature extremes) or psychological (fear, anxiety, grief, social conflict). A stressor is the specific agent or event causing stress. The body's response to any stressor is coordinated by the sympathetic nervous system and the hypothalamic-pituitary-adrenal (HPA) axis, an integrated endocrine pathway. Hans Selye (1936) described the General Adaptation Syndrome (GAS), a nonspecific three-stage response to any stressor, applicable across NCM Levels I–III (dependent to independent nursing care): **Alarm Stage (Acute Phase)** The 'fight-or-flight' response activates within seconds to minutes. The sympathetic nervous system releases catecholamines (epinephrine from adrenal medulla, norepinephrine from sympathetic neurons), and the anterior pituitary releases corticotropin (ACTH), stimulating cortisol release from the adrenal cortex. Simultaneously, the posterior pituitary releases ADH (antidiuretic hormone). Physiologic effects: - Increased heart rate and contractility (cardiac output ↑) - Increased respiratory rate and depth (oxygen uptake ↑) - Pupil dilation and improved alertness (blood diverted from GI tract to brain and muscles) - Increased blood glucose (glycogenolysis in liver, gluconeogenesis; cortisol ↑ and epinephrine ↑) - Increased blood pressure (vasoconstriction in non-vital organs, vasodilation in vital organs) - Decreased digestive and immune activity (metabolic shift from 'rest and digest' to 'fight and flight') - Increased serum sodium and water retention (aldosterone effect) Clinical correlation: Postoperative patients commonly show tachycardia, hypertension, rapid respirations, restlessness, hyperglycemia, and fluid retention in the immediate postoperative period—all manifestations of the alarm stage. **Resistance (Adaptation) Stage** If the stressor is manageable, the body attempts to stabilize vital signs and return toward homeostasis (hours to days). The HPA axis remains elevated but more controlled. Immune function partially recovers. However, if the stressor persists (chronic illness, prolonged hospitalization, uncontrolled infection), the body remains in a state of heightened vigilance with ongoing cortisol and catecholamine elevation. **Exhaustion Stage** If the stressor is severe, prolonged, or overwhelming beyond the body's adaptive capacity (septic shock, massive trauma, starvation), adaptive reserves deplete. Cortisol and catecholamine levels eventually decline; the sympathetic response fails; and the body enters a state of decompensation. Hypotension, altered mental status, oliguria, and eventually multiple organ dysfunction syndrome (MODS) and death ensue if intervention is not immediate. Clinical correlation: The exhaustion stage explains why a patient in septic shock, despite initial compensatory tachycardia and hypertension, may suddenly 'crash' when vasomotor tone collapses—the adrenal exhaustion phase. **Local Adaptation Syndrome (LAS)** A localized stress response occurs at a specific tissue site, such as inflammation at a wound. While GAS is whole-body, LAS is compartmentalized. Example: A minor surgical wound activates local inflammatory mediators (histamine, bradykinin) without triggering systemic fever or tachycardia unless the wound becomes infected. **Key Stress Hormones and Their Actions:** - **Cortisol**: Raises blood glucose (glycogenolysis, gluconeogenesis), increases protein catabolism, suppresses inflammation and immune response, promotes sodium and water retention, and has CNS effects (mood changes, memory) - **Aldosterone**: Promotes sodium reabsorption in kidney collecting ducts, secondarily increasing water reabsorption (raises blood volume and pressure) - **ADH (Vasopressin)**: Increases water reabsorption in collecting ducts (conserves water, increases blood osmolality and volume) - **Epinephrine/Norepinephrine**: Increase heart rate, contractility, blood pressure, and blood glucose Implications for nurses in Philippine clinical settings: Recognize that ANY significant stress (surgery, acute illness, pain, fear, malnutrition, heat exposure) triggers GAS; postoperative and acutely ill patients may exhibit hyperglycemia even without diabetes due to stress-induced catecholamine and cortisol release. Use stress-reduction strategies (pain management, reassurance, quiet environment) to minimize physiologic stress load. Monitor vital signs and glucose in acutely stressed patients per NCM protocols. Educate patients on stress management and coping mechanisms.

Cells continuously adapt to environmental demands through reversible changes in size, number, and differentiation. When injury exceeds adaptive capacity, cell death occurs. Understanding these mechanisms explains many clinical presentations in acute and chronic illness. **Reversible Cellular Adaptations:** These changes preserve cell viability and allow tissues to meet altered demands. All are reversible if the causative stimulus is removed. 1. **Atrophy** — Decrease in cell size and organ mass. Caused by disuse, denervation, inadequate blood supply, or aging. Example: Muscles atrophy within days of immobilization (bed-bound patient) or spinal cord injury (denervation); brain atrophies in Alzheimer's disease. Nursing implication: Early mobilization, range-of-motion (ROM) exercises, electrical stimulation in paralyzed patients (NCM Level II) to minimize atrophy. 2. **Hypertrophy** — Increase in cell size (not number) in response to increased functional demand. Example: Weight lifters develop muscle hypertrophy; left ventricle hypertrophies in chronic hypertension as it works harder to pump against elevated afterload. While initially compensatory, chronic hypertrophy can lead to reduced contractility (dilated cardiomyopathy). Nursing implication: Antihypertensive therapy to reduce afterload and prevent maladaptive hypertrophy. 3. **Hyperplasia** — Increase in cell number (mitotic division) in response to increased demand. Example: Bone marrow hyperplasia during chronic anemia (↑ RBC production) or infection (↑ WBC production); breast tissue hyperplasia during pregnancy (estrogen-driven). Often accompanies hypertrophy. Nursing implication: Monitor CBC in chronic disease; educate on iron, vitamin B12, folate intake for sustained erythropoiesis. 4. **Metaplasia** — Reversible change of one mature cell type to another in response to chronic irritation. Example: Chronic smoking → squamous metaplasia of respiratory epithelium (normally ciliated columnar) in bronchi → loss of protective ciliary action → increased mucus stasis and infection risk. Another example: Barrett's esophagus (chronic GERD → squamous epithelium of esophagus metaplasizes to gastric mucosa). Nursing implication: Smoking cessation counseling; GERD management (PPIs, diet modification, positioning) to prevent progression to dysplasia or cancer. 5. **Dysplasia** — Disordered, abnormal growth characterized by increased nuclear:cytoplasmic ratio, irregular nuclei, hyperchromatic nuclei (darkly staining), and increased mitosis. Dysplasia is **not cancer but premalignant**; it indicates cells are escaping normal growth controls. Causes: chronic irritation, carcinogens (tobacco, alcohol, UV radiation, HPV). Example: Cervical dysplasia (CIN I, II, III) preceding cervical cancer; actinic keratosis from sun exposure preceding squamous cell carcinoma. Nursing implication: Cervical cancer screening (PAP smears per DOH Philippine Cancer Control Program); skin cancer prevention counseling; HPV vaccination in adolescents; smoking and alcohol cessation. **Irreversible Cellular Injury — Cell Death:** When adaptive mechanisms fail and injury is severe or prolonged, cell death occurs by two pathways: 1. **Necrosis** — Uncontrolled cell death from injury (hypoxia, trauma, severe infection, chemical injury). Cell membrane ruptures, intracellular contents spill into tissue, triggering a strong inflammatory response. Necrosis is messy, damaging, and causes tissue injury beyond the originally damaged area. Histologic appearance: cell and nuclear lysis, loss of architectural detail, inflammation. Example: Acute myocardial infarction (MI) → cardiac myocyte necrosis due to ischemia → inflammatory infiltrate (neutrophils, then macrophages) → scar formation. Nursing implication: Post-MI nursing care includes pain management, antiplatelet therapy, ACE inhibitors, monitoring for arrhythmias and heart failure (NCM Levels II–III). 2. **Apoptosis** — Programmed, orderly cell death. Cell membrane remains intact; cell shrinks; nuclear chromatin condenses (pyknosis) and fragments (karyorrhexis); cell fragments into apoptotic bodies taken up cleanly by macrophages without inflammatory response. Apoptosis is 'immunologically silent' and leaves no scarring. Normal in development (separation of fingers in embryo), tissue remodeling, and elimination of aberrant (potentially cancerous) cells. Regulated by genes (BCL-2 family). Example: Hormone-dependent breast cancer cells undergo apoptosis when tamoxifen blocks estrogen signaling. Nursing implication: Understand that chemotherapy and many targeted therapies work by triggering apoptosis; side effects relate to killing normal cells alongside cancer cells. **Causes of Cellular Injury:** 1. **Hypoxia/Ischemia** (most common): Reduced oxygen delivery to cells. Causes: respiratory failure, anemia, cardiovascular disease, shock, carbon monoxide poisoning. Cells switch to anaerobic metabolism → ATP depletion → Na+/K+ ATPase failure → cellular edema → cell death. 2. **Physical agents**: Trauma, burns, radiation, temperature extremes. 3. **Chemical agents**: Toxins (heavy metals, drugs, solvents), caustics, poisons. 4. **Infectious agents**: Bacteria, viruses, fungi, parasites (direct invasion or toxin production). 5. **Immune reactions**: Autoimmune disease, transplant rejection. 6. **Nutritional imbalances**: Protein-energy malnutrition, vitamin deficiencies (thiamine, vitamin C, B12). 7. **Genetic abnormalities**: Cystic fibrosis, hemophilia. 8. **Aging**: Telomere shortening, accumulated DNA damage, mitochondrial dysfunction. Clinical correlation: The progression from adaptation → injury → dysfunction → death illustrates the importance of early intervention. A patient with chronic anemia initially adapts through RBC hyperplasia and cardiac hypertrophy (increased cardiac output); if anemia worsens, the heart decompensates (dilated cardiomyopathy); without RBC transfusion or EPO therapy, death follows.

Inflammation is the body's immediate, **nonspecific protective response** to tissue injury or invasion by foreign agents. It is distinct from infection—infection is inflammation caused specifically by pathogenic microorganisms. Inflammation occurs in response to sterile trauma, burns, myocardial infarction, surgery, and countless other insults. **Purposes of Inflammation:** 1. Neutralize and destroy harmful agents (bacteria, toxins, foreign bodies). 2. Limit the spread and prevent dissemination of pathogens or irritants. 3. Prepare the tissue for healing and restoration of normal architecture. 4. Remove debris and dead cells to make way for new tissue. **Chemical Mediators of Inflammation:** Following tissue injury, mast cells and damaged endothelial cells release: 1. **Histamine** — Released from mast cells and basophils; causes vasodilation and increased capillary permeability within minutes (immediate response); responsible for early erythema and edema; blocked by antihistamines. Found in degranulated mast cells in inflamed tissue. 2. **Bradykinin** — A peptide released from plasma kinins; causes pain, vasodilation, and smooth muscle contraction; amplifies vascular permeability. One of the most potent pain mediators; responsible for dolor (pain) in inflammation. 3. **Prostaglandins** (PGE2, PGI2) — Eicosanoids derived from arachidonic acid via COX pathway; cause vasodilation, increased permeability, and pain; also regulate fever at the hypothalamus (PGE2 raises set point); blocked by NSAIDs and COX inhibitors. Explain why febrile patients with NSAIDs (paracetamol, ibuprofen) show rapid temperature reduction. 4. **Leukotrienes** (LTC4, LTD4, LTE4) — Eicosanoids from arachidonic acid via LOX pathway; potent vasodilators and leukocyte chemoattractants; also cause bronchospasm and mucus secretion (explain allergic airway response). Blocked by leukotriene receptor antagonists (montelukast). 5. **Complement proteins** (C3a, C5a) — Plasma proteins activated in cascade following infection or immune complex deposition; promote vasodilation, chemotaxis, and phagocytosis; amplify inflammatory response. 6. **Cytokines** — Secreted by activated immune cells (IL-1, TNF-α, IL-6, IL-8); systemic effects include fever, acute-phase protein synthesis, leukocytosis, and metabolic changes; important in systemic inflammatory response syndrome (SIRS) and sepsis. **Vascular and Cellular Events of Inflammation:** **Immediate Phase (Minutes):** - Vasodilation (arterioles → capillaries) mediated by histamine and prostaglandins → increased blood flow → redness (rubor) and heat (calor). - Increased capillary hydrostatic pressure and endothelial cell contraction → widened intercellular junctions → increased capillary permeability → plasma protein and fluid leak into tissue → swelling (tumor/edema). - Stasis of blood in microvasculature (from fluid loss and slow flow) → increased WBC margination (WBCs move to periphery of vessel). **Early Cellular Phase (Hours):** - Marginated neutrophils adhere to endothelium (adhesion molecules: selectins, integrins) → emigration through endothelium (diapedesis) → chemotaxis toward chemical gradients (complement C5a, bacterial products, IL-8) → recruitment to inflamed tissue. - Neutrophils (polymorphonuclear leukocytes, PMNs) predominate in the first 6–24 hours; recognize, engulf, and destroy pathogens and debris through phagocytosis. - Macrophages arrive within 24–48 hours; phagocytose larger debris, dead cells, and bacteria; secrete cytokines that amplify inflammation and promote healing (TNF-α, IL-1, IL-6). - Eosinophils arrive in parasitic infections and allergic responses. **Five Cardinal Signs of Inflammation (Celsus, Virchow):** These are the **classic local signs** of inflammation at the site of injury: 1. **Rubor** — Redness. From vasodilation and increased blood flow bringing oxygenated RBCs. 2. **Calor** — Heat. From increased metabolic activity and blood flow. 3. **Tumor** — Swelling/edema. From fluid shift into tissue due to increased capillary permeability. 4. **Dolor** — Pain. From pressure of edema on nerves and chemical mediators (bradykinin, prostaglandins) stimulating nociceptors. 5. **Functio laesa** — Loss of function. From pain and swelling limiting movement of affected part. (Added by Virchow; not always present.) Example: Acute appendicitis → inflammation of appendix → rubor (redness of serosal surface), calor (increased blood flow), tumor (edema of appendical wall and peritoneal fluid exudate), dolor (periumbilical pain shifting to RLQ), functio laesa (guarding, limited ambulation). On exam: RLQ tenderness, rebound tenderness, Rovsing's sign (pain RLQ when LLQ palpated), McBurney's point tenderness. **Systemic Manifestations of Inflammation:** When inflammation is widespread or severe, systemic effects occur: 1. **Fever (Pyrexia)** — Rise in body temperature above 37.5°C. Caused by prostaglandin E2 (and cytokines IL-1, TNF-α, IL-6) acting on the hypothalamic thermoregulatory center, raising the set point. Fever is **beneficial** (enhances immune function, inhibits some pathogen growth) unless extreme (>40.5°C, risk of delirium, seizure). Nursing implication: Avoid aggressive antipyretic therapy unless patient uncomfortable; tepid sponging is less effective than NSAIDs or acetaminophen, which block prostaglandin synthesis. 2. **Leukocytosis** — Elevated WBC count (>11,000/μL) due to accelerated release of mature neutrophils from bone marrow (left shift: increased immature forms like bands and metamyelocytes indicates severe infection or inflammation). WBC differential: neutrophils predominate in bacterial infection; lymphocytes in viral infection; eosinophils in parasitic or allergic responses. Nursing implication: CBC with differential helps identify infection etiology; 'shift to the left' signals need for urgent antibiotic therapy and source control. 3. **Malaise** — General feeling of being unwell; fatigue; attributed to circulating cytokines and metabolic drain. 4. **Acute-Phase Response** — Hepatic synthesis of acute-phase proteins: - **C-Reactive Protein (CRP)** — Rises within hours of infection/inflammation; nonspecific marker. Normal <10 mg/L; elevated in infection, MI, autoimmune disease. More sensitive and rises faster than ESR. - **Erythrocyte Sedimentation Rate (ESR)** — Slowness of RBC settling in plasma; rises due to increased fibrinogen and immunoglobulins coating RBCs. Normal <20 mm/hr (age and sex dependent). Slower to rise than CRP but more sustained; less specific. - Other acute-phase proteins: Ferritin, serum amyloid A, procalcitonin (elevated in bacterial/fungal infection). 5. **Metabolic Changes** — Increased oxygen consumption, increased temperature from metabolic heat, increased protein catabolism (negative nitrogen balance), hyperglycemia (stress hormones), and changes in iron and zinc metabolism. Clinical correlation: A postoperative patient with fever, leukocytosis (WBC 14,000 with left shift), elevated CRP, tachycardia, and malaise on postoperative day 3 suggests surgical site infection (SSI). Wound assessment for purulent drainage, erythema, warmth, and induration is essential (NCM Level II). Culture and empiric broad-spectrum antibiotics, followed by targeted therapy per culture, are indicated per hospital infection control protocols. **Resolution of Inflammation:** Once the harmful agent is neutralized and debris cleared, inflammation resolves through: 1. Reduced chemical mediator release (mast cells degranulate briefly). 2. Activation of anti-inflammatory mediators (IL-10, TGF-β, lipoxins, resolvins). 3. Apoptosis of neutrophils and macrophages (orderly death without secondary inflammation). 4. Restoration of endothelial barrier function and reduced vascular permeability. 5. Lymphatic drainage of edema fluid back to circulation. 6. Healing phase begins (proliferative phase with granulation tissue formation). **Chronic Inflammation:** If the causative agent persists or the body cannot effectively clear it, inflammation becomes chronic, lasting weeks to years. Characterized by lymphocyte and macrophage predominance, fibroblast proliferation, and often granuloma formation. Examples: Tuberculosis, chronic osteomyelitis, rheumatoid arthritis, Crohn's disease, chronic cholecystitis. Complications include tissue fibrosis, adhesions, organ dysfunction, and malignancy risk (chronic HPV infection → cervical cancer; chronic hepatitis B → hepatocellular carcinoma). Nursing implications: Long-term anti-inflammatory therapy (NSAIDs, corticosteroids, immunosuppressants), infection prevention and control, symptom management, and monitoring for complications.

Wound healing is a complex, overlapping process of inflammatory, proliferative, and remodeling phases. Understanding these phases guides nursing interventions to optimize healing outcomes and prevent complications—critical in Philippine healthcare settings where resources may be limited and infection risk high. **Classification of Wound Healing:** 1. **Primary Intention (First Intention)** — Clean, approximated wound edges with minimal scarring. Occurs in surgical incisions closed with sutures (clean-contaminated surgery). Phases overlap within days to weeks. Example: Planned abdominal surgery with primary closure. 2. **Secondary Intention** — Open wound healing from the base upward by granulation, epithelialization, and contraction. More scarring and longer duration (weeks to months). Occurs in deep wounds, infected wounds, or wounds left open (traumatic wounds, extensive burns). Example: Pressure ulcer (bedsore) left open to drain and heal from inside out. 3. **Tertiary Intention (Delayed Primary Closure)** — Wound left open initially (to allow infection/edema to resolve), then closed after several days. Used in contaminated or high-infection-risk wounds. Example: Traumatic laceration with heavy contamination; cleaned, debrided, left open 48 hours; then sutured once infection risk reduced. **Three Overlapping Phases of Wound Healing:** **Phase 1: Inflammatory Phase (0–3 days; dominates first 24 hours)** *Immediate response (minutes to hours):* - Hemostasis: Platelet plug formation and clotting cascade halt bleeding. - Vasodilation and increased capillary permeability (histamine, prostaglandins) → edema, erythema, and fibrin exudate rich in platelets, fibrinogen, and growth factors. *Cellular response (hours to 3 days):* - Neutrophil migration into wound (chemotaxis by complement, bacterial products). - Neutrophils (PMNs) phagocytose bacteria, debris, and dead tissue; peak at 24–48 hours. - Macrophages arrive at 24–48 hours; phagocytose debris and neutrophils; secrete growth factors (TGF-β, VEGF, FGF, PDGF) essential for proliferative phase. - Fibrin clot protects wound and serves as scaffold for new tissue. *Clinical observation:* - Wound is red, warm, swollen, tender—the cardinal signs of inflammation. - Serosanguineous exudate (clear with some RBCs) is normal and protective (immune cells, growth factors, fibrin). - Purulent drainage (thick, green, yellow) indicates infection and requires culture and antibiotics. *Nursing care in inflammatory phase:* - Keep wound clean but avoid aggressive scrubbing (disrupts fibrin scaffold). - Use appropriate dressing (gauze for infected/draining wounds allowing drainage; moist dressings for dry wounds promoting autolysis of dead tissue). - Monitor for signs of infection: increasing purulence, erythema beyond wound margins, warmth, induration, systemic fever, leukocytosis. - Pain management (analgesia before dressing changes). - Nutritional support (protein for immune cell synthesis and collagen; vitamin C for collagen stability). **Phase 2: Proliferative Phase (3–21 days; overlaps with and follows inflammatory)** *Cellular events:* - Fibroblast proliferation and migration into wound (stimulated by growth factors: TGF-β, PDGF, FGF from macrophages). - **Collagen deposition** — Fibroblasts synthesize Type I collagen (abundant, strong) and Type III collagen (temporary); collagen cross-linking increases tensile strength. **Requires vitamin C (hydroxylation of proline and lysine), zinc, and adequate protein intake.** - **Angiogenesis** — New capillary formation from existing vessels (VEGF-mediated); restores blood supply to healing tissue. - **Epithelialization** — Epidermal cells at wound edges migrate across the wound bed, proliferate, and differentiate; forms new epidermal layer. Aided by moist wound environment. - **Granulation tissue formation** — Loose, red, bumpy tissue consisting of new capillaries, fibroblasts, collagen, and extracellular matrix. Gradually replaces fibrin clot. - **Wound contraction** — Myofibroblasts (contractile fibroblasts) contract, reducing wound size by 50–80% in open wounds, promoting faster closure and reducing scarring. Most prominent in secondary intention wounds. Can cause functional problems if excessive (contracture). *Clinical observation:* - Wound changes from red/edematous/exudative to pale pink/firm/granular. - Scar tissue begins to form (appears as slightly raised, paler tissue). - Tensile strength increases from near zero at 3 days to ~50% of original tissue strength at 3 weeks. *Nursing care in proliferative phase:* - Maintain moist wound environment (promotes epithelialization; excessive moisture causes maceration). - Nutritional support critical: protein (synthesis of collagen and immune factors), vitamin C (collagen cross-linking, immune function), zinc (cell proliferation, protein synthesis), calories for energy. - Avoid wound contamination (aseptic dressing changes, handwashing, sterile technique per NCM Levels II–III). - Manage pain and position to reduce tension on wound (promotes epithelialization). - Monitor wound size, color, exudate (should be minimal, serosanguineous). **Phase 3: Maturation/Remodeling Phase (3 weeks to months/years)** *Cellular events:* - Collagen remodeling: Type III collagen (temporary, weak) replaced by Type I collagen (strong, permanent). - Collagen cross-linking increases; scar tissue gains tensile strength (reaches ~80% of original at 3 months, ~90% at 1–2 years, never 100%). - Apoptosis of excess fibroblasts and capillaries; scar tissue becomes thinner, paler, less vascular. - Scar may flatten and become less noticeable over months to years (cosmetic improvement). *Tensile strength trajectory:* - Day 0–5: Minimal strength (depends on fibrin clot); risk of dehiscence if tension applied. - Day 5–14: Collagen deposition increases strength to ~25% of original. - Day 14–21: Strength ~50% of original; sutures can be removed (wound less likely to dehisce). - 3–6 months: ~80% of original strength. - 1–2 years: ~90% of original strength (never fully recovers). *Clinical observation:* - Scar initially red, raised, firm (hypertrophic); over months to years, becomes flat, pale, less prominent. - In some individuals, excessive collagen deposition → keloid (raised, irregular, often itchy scar extending beyond original wound margins); more common in darker-skinned individuals and on chest, shoulders. *Nursing care in maturation phase:* - Scar care: Silicone gel sheeting, massage (once epithelialization complete) may help flatten scars. - Sun protection (UV exposure darkens healing scars; use sunscreen). - Activity progression (scar strengthens with gentle stretching; excessive immobility → contracture). - Psychological support (patients may be concerned about appearance; reassure that scars improve over time). **Factors Impairing Wound Healing:** Understanding these factors enables nurses to identify and address barriers to healing per NCM protocols. 1. **Poor Perfusion** — Inadequate blood supply limits oxygen, nutrients, and immune cell delivery. Causes: cardiovascular disease, diabetes with vasculopathy, anemia, shock, extreme cold, smoking (nicotine causes vasoconstriction). Management: Improve cardiovascular status, optimize hematocrit, smoking cessation, warm environment, offloading pressure in pressure ulcers. 2. **Infection** — Bacteria consume oxygen and produce toxins; neutrophils fight infection but also cause tissue damage; bacterial burden >10^5 per gram impairs healing. Signs: Purulent drainage, increasing erythema, warmth, systemic fever, odor. Management: Culture, antibiotics (systemic for cellulitis, topical for minor infection), aseptic technique, debridement of necrotic tissue. 3. **Diabetes Mellitus** — Hyperglycemia impairs neutrophil function, collagen synthesis, and angiogenesis; diabetic neuropathy → inability to feel injury/pressure → recurrent trauma; macrovascular and microvascular disease → poor perfusion. Complications: Diabetic foot ulcers (high amputation risk). Management: Tight glycemic control (target glucose 120–180 mg/dL perioperatively per protocols), foot care education, offloading, vascular assessment. 4. **Corticosteroid Use** — Suppresses immune response and collagen synthesis; masks infection signs. Management: Use lowest effective dose; monitor closely for infection; adequate nutrition and vitamin C supplementation. 5. **Malnutrition** — Protein deficiency → inadequate collagen synthesis, reduced immune function (↓ neutrophil and macrophage function), slow granulation. Vitamin C deficiency → defective collagen cross-linking, increased capillary fragility, anemia. Zinc deficiency → impaired epithelialization, reduced immune response. Caloric deficiency → energy unavailable for healing metabolism. Management: Nutritional assessment; protein 1.5–2 g/kg/day; vitamin C 500–1000 mg/day; zinc 15–30 mg/day; adequate calories; enteral feeding if oral intake inadequate; consider albumin level (<3.5 g/dL indicates protein malnutrition). 6. **Extremes of Age** — Infants have immature immune systems; elderly have reduced immune function, slower collagen synthesis, more fragile skin. Management: Gentle handling, adequate nutrition, frequent repositioning to prevent pressure ulcers. 7. **Chronic Illness** — Renal disease, liver disease, cancer, HIV/AIDS → impaired immune and metabolic function. Management: Treat underlying disease; optimize nutritional status; monitor closely. 8. **Medications** — Anticoagulants increase bleeding; immunosuppressants reduce immune response; NSAIDs inhibit inflammation (sometimes beneficial but can delay healing if excessive). Management: Weigh risks/benefits; supplement with nutrition; monitor healing progress. 9. **Excessive Inflammation or Mechanical Stress** — Excessive edema impairs oxygen diffusion; tension on wound edges causes dehiscence and widened scar; repeated trauma (scratching, aggressive cleaning) disrupts healing tissue. Management: Elevation and compression to reduce edema; offloading pressure; gentle handling; protect wound from trauma. 10. **Foreign Bodies and Necrotic Tissue** — Sutures, gauze fibers, bone fragments, devitalized tissue act as nidus for infection and impair healing. Management: Proper wound exploration and irrigation; sterile technique; debridement of devitalized tissue; removal of sutures at appropriate time. **Complications of Wound Healing:** 1. **Dehiscence** — Separation of wound layers (superficial: epidermis/dermis; deep: fascia/muscle). Occurs most commonly at day 5–8 (before collagen strength sufficient). Causes: infection, malnutrition, coughing/straining in abdominal wounds, obesity (increased tension on closure). Signs: Sudden drainage increase, opening of wound, visible tissue. Management: Notify physician; may require re-suturing; assess for underlying causes; cough control (splinting, analgesics) in abdominal wounds; activity restriction until healed. 2. **Evisceration** — Protrusion of internal organs through dehisced wound. Medical emergency. Management: Place sterile, moist dressing over opening; keep patient NPO; notify physician immediately; prepare for OR; prevent contamination. 3. **Excessive Scar Formation** — Hypertrophic scars (raised, red, remain within wound margins, may regress over time) or keloids (extend beyond wound margins, grow indefinitely, don't regress). More common in darker skin. Management: Pressure garments, silicone sheeting, topical treatments, or steroid injections; surgical revision in severe cases. 4. **Contracture** — Excessive wound contraction limiting function of underlying joints (common in burn wounds and pressure ulcers). Prevention better than treatment: Early grafting (in burns), splinting, ROM exercises. Management: Surgical release, skin grafting, ROM therapy. 5. **Infection** — Covered above. Can delay healing from weeks to months; risk of cellulitis, abscess, sepsis. Clinical correlation for Philippine settings: Post-operative patients in resource-limited settings face high SSI risk due to heat, humidity, limited resources for sterile dressing changes, and delayed antibiotic access. Emphasis on aseptic technique (NCM Level II), early mobilization, adequate nutrition (often limited by cost), and infection surveillance is critical per DOH infection control guidelines.

Illness and injury cause fluid to shift abnormally between body compartments, disrupting the balance necessary for adequate tissue perfusion. Understanding these shifts is essential for managing fluid status in acute care settings per NCM protocols. **Body Fluid Compartments:** - **Total body water (TBW)**: ~60% of body weight in young adults; ~50% in elderly (increased body fat displaces water). - **Intracellular fluid (ICF)**: ~40% of body weight (2/3 of TBW); inside cells; high in K+, Mg2+, proteins; low in Na+, Cl-. - **Extracellular fluid (ECF)**: ~20% of body weight (1/3 of TBW); outside cells: - **Intravascular** (plasma): ~4% body weight (5% of ECF); inside blood vessels; contains proteins, glucose, ions, RBCs. - **Interstitial**: ~15% body weight (75% of ECF); bathes cells; lower protein than plasma. - **Transcellular**: ~1% of ECF; cerebrospinal fluid, synovial fluid, aqueous humor—small but critical compartments. Example: 70 kg person: TBW = 42 L; ICF = 28 L; ECF = 14 L (Intravascular 3.5 L, Interstitial 10.5 L). **Forces Governing Fluid Movement (Starling Forces):** Fluid moves between intravascular and interstitial spaces based on hydrostatic and oncotic (colloidal osmotic) pressures: 1. **Hydrostatic Pressure (HP)** — The physical "pushing" force exerted by fluid against vessel walls. High hydrostatic pressure pushes fluid OUT of vessels into interstitium. Increased by: - Increased blood pressure (hypertension, fluid overload). - Venous obstruction (DVT, tumor compression, pregnancy). - Increased central venous pressure (heart failure, pulmonary edema from over-transfusion). - Gravity in dependent areas (leg swelling when sitting/standing for long periods). Example: Acute heart failure → ↑ CVP → ↑ capillary hydrostatic pressure → pulmonary edema, peripheral edema, ascites. 2. **Oncotic (Colloid Osmotic) Pressure (OP)** — The "pulling" force created by large molecules (proteins, especially albumin) in plasma. The higher the plasma protein concentration, the greater the pulling force keeping fluid IN the vessels. Decreased by: - Hypoalbuminemia (liver disease, nephrotic syndrome, malnutrition, enteropathies, sepsis). - Decrease in plasma protein concentration. Example: Cirrhotic patient with portal hypertension and hypoalbuminemia (2.0 g/dL) → ↓ oncotic pressure → fluid leaks from intravascular to interstitial and peritoneal spaces → ascites, peripheral edema, depleted intravascular volume. **Starling Equation (Conceptual):** Net fluid filtration = (HPcapillary - HPinterstitium) - (OPcapillary - OPinterstitium) When hydrostatic pressure overwhelms oncotic pressure, or oncotic pressure is depleted, fluid moves into the interstitium → edema. **Third-Spacing: Pathologic Fluid Shift:** **Definition:** Fluid shifts from the intravascular space into a "third" space (interstitium, peritoneal cavity, pleural space, pericardial sac, bowel lumen, tissue spaces) where it is **not readily accessible to support circulation**. Although total body water may be normal or even high, the **functional circulating volume is depleted**, producing signs of hypovolemia despite visible edema. The paradox of third-spacing: Patient is edematous (visible swelling) yet hypovolemic (low blood pressure, decreased urine output, signs of inadequate perfusion)—this confuses inexperienced nurses who see edema and assume fluid overload. **Causes of Third-Spacing:** 1. **Burns** (thermal injury) — Tissue damage → massive capillary permeability increase → plasma leaks into tissue (burn edema) and peritoneal space. Massive third-spacing can occur in first 24–48 hours; burns >15% body surface area (BSA) in adults require aggressive IV fluid resuscitation (Parkland formula) to prevent hypovolemic shock. Example: 50% BSA burn → can lose 5–10 L of plasma into tissue within hours. 2. **Sepsis/Infection** — Bacterial endotoxins and inflammatory cytokines (TNF-α, IL-1, IL-6) → capillary permeability increase → fluid weeps into tissue and body cavities. Septic shock is a form of distributive shock with massive third-spacing. Example: Severe pneumonia with sepsis → pulmonary edema (fluid in alveoli), peripheral edema, yet systemic hypotension. 3. **Major Surgery** — Surgical trauma → inflammatory response with capillary permeability increase → fluid shifts into tissue and into the wound site. Major abdominal surgery can result in 5–10 L third-spacing; IV fluids are given to maintain intravascular volume during and after surgery. The body gradually reabsorbs this fluid over 3–7 days (reabsorption phase). 4. **Bowel Obstruction** — Blocked bowel → distension → inflammation → increased capillary permeability → fluid and electrolytes leak into bowel lumen ('lost' to circulation) and peritoneal space. Severe third-spacing in complete obstruction; risk of hypovolemic shock and electrolyte imbalance. Example: Adhesive bowel obstruction post-abdominal surgery → vomiting, abdominal distension, intravascular volume depletion. 5. **Acute Pancreatitis** — Pancreatic inflammation → increased capillary permeability → third-spacing into retroperitoneal space and abdomen (hemorrhagic pancreatitis can be life-threatening). Severe cases require aggressive IV hydration to prevent shock and acute kidney injury. 6. **Hypoalbuminemia** — Severe protein malnutrition, liver cirrhosis, nephrotic syndrome (protein loss in urine), enteropathies (malabsorption), sepsis → serum albumin <2.5 g/dL → ↓ oncotic pressure → fluid leaks into interstitium despite normal hydrostatic pressure. Example: Malnourished patient in resource-limited setting with kwashiorkor (protein malnutrition) → edema, ascites, hepatomegaly, yet hemodynamically unstable. 7. **Peritonitis/Abdominal Inflammation** — Bacterial or chemical peritonitis → inflammation of peritoneal membrane → capillary permeability increase → massive fluid sequestration in peritoneal cavity. Example: Perforated peptic ulcer → peritonitis → third-spacing into peritoneum → severe hypovolemic shock if untreated. **Clinical Manifestations of Third-Spacing:** *Local manifestations:* Edema (pitting or non-pitting depending on location and cause), weight gain, increased abdominal girth, ascites (fluid in peritoneal cavity), pulmonary edema (orthopnea, PND, crackles), peripheral edema (ankles, sacrum in immobile patients). *Systemic manifestations (indicating hypovolemia):* - Hypotension (low BP, orthostatic changes). - Tachycardia (compensatory, to maintain cardiac output). - Tachypnea (from acidosis and hypoxemia in pulmonary edema). - Oliguria (reduced urine output <30 mL/hr; kidneys struggle to maintain perfusion pressure). - Delayed capillary refill (>2 seconds; poor peripheral perfusion). - Cool, clammy skin (peripheral vasoconstriction to preserve core perfusion). - Altered mental status (hypoxemia, hypoperfusion to brain). - Thirst (osmoreceptors sense increased plasma osmolality from fluid loss). - Elevated BUN/creatinine ratio (prerenal azotemia; inadequate renal perfusion). **Distinguishing Third-Spacing from Other Fluid Imbalances:** | Finding | Third-Spacing | Fluid Overload | Dehydration | |---------|---------------|----------------|-------------| | Edema | Present | Present | Absent | | BP | Low/Normal* | High/Normal | Low | | Heart rate | Elevated | Normal/Elevated | Elevated | | Urine output | Low | Normal/High | Low | | Skin turgor | Normal/Decreased | Normal | Decreased | | Mucous membranes | Normal/Dry | Normal | Dry | | CVP | Low* | High | Low | | Serum Na | Variable | Normal/Low | High | | Serum albumin | Low | Normal | Normal | *In third-spacing, blood pressure may initially be normal or even elevated due to compensatory tachycardia and vasoconstriction; however, as intravascular volume depletes, hypotension develops. **Nursing Management of Third-Spacing:** 1. **Assessment (NCM Level II–III):** - Monitor vital signs q1–2h or more frequently if unstable. - Measure accurate intake and output (I&O); oliguria (<30 mL/hr) signals inadequate perfusion. - Daily weights (sudden gain 1–2 kg/day suggests fluid retention; should be matched by increased I&O or attributed to specific fluid bolus given). - Assess edema (location, pitting vs. non-pitting, progression). - Examine for manifestations of hypovolemia: hypotension, tachycardia, delayed capillary refill, cool extremities, altered mental status. - Monitor serum albumin, electrolytes (Na, K, Cl), BUN/creatinine, hematocrit (elevated in hypovolemia due to hemoconcentration). - Assess for underlying cause: assess wound (infection?), abdomen (ascites, distension?), lung auscultation (crackles?), temperature (fever suggesting infection?). 2. **Fluid Administration:** - **Crystalloids** — Isotonic solutions (0.9% NaCl, Lactated Ringer's) are first-line in hypovolemic states. Normal saline is readily available and recommended in Philippine healthcare settings. Large-bore IV access (18-gauge or larger) for rapid infusion. - **Bolus therapy** — In shock or severe hypovolemia, rapid IV bolus (500 mL–1 L isotonic crystalloid over 15–30 minutes) restores intravascular volume quickly. - **Maintenance fluids** — Once intravascular volume restored, slower infusion (100–150 mL/hr, depending on ongoing losses and output) maintains balance. - **Blood products** — In severe hemorrhage or massive third-spacing with persistent hypotension despite crystalloids, consider transfusion (per hospital protocols, type & cross before transfusion). 3. **Reabsorption Phase Management (Days 3–7 post-initial insult):** - As the inflammatory stimulus resolves (infection treated, burn eschar forms barrier, surgical trauma heals), third-spaced fluid gradually re-enters the intravascular space (diuretic phase). - This reabsorption can precipitate **fluid overload** if IV infusions are not reduced. - Watch for signs of fluid overload: hypertension, increased CVP, pulmonary edema (crackles, orthopnea, PND), peripheral edema worsening, increased urine output. - Action: Reduce IV infusion rate once diuretic phase begins; monitor for pulmonary edema (especially in elderly, renal disease); administer diuretics (furosemide) if pulmonary edema develops. - Classic scenario: Burn patient who received 10 L crystalloid in first 24 hours; now on day 3 with improving wound perfusion, increased urine output (no longer oliguria), rising CVP → reduce IV rate to maintenance to prevent pulmonary edema during reabsorption phase. 4. **Address Underlying Cause:** - Infection: Antibiotics, source control (drainage, debridement). - Bowel obstruction: NG tube decompression, bowel rest, surgical intervention if indicated. - Hypoalbuminemia: Nutritional support (protein, vitamins), albumin infusion in severe cases (controversial; some protocols reserve albumin for specific indications like severe liver disease). - Burns: Early excision and grafting to reduce ongoing capillary permeability and inflammatory mediator release. 5. **Nutritional Support:** - Protein (1.5–2 g/kg/day) to restore serum albumin (goal >3.5 g/dL); improves oncotic pressure and aids healing. - Enteral feeding preferred over IV nutrition if GI tract functional (lower cost, better outcomes in Philippine settings with resource constraints). - Vitamins C, A, zinc for immune function and healing. 6. **Position and Activity:** - Elevate edematous extremities to reduce dependent edema and promote drainage to larger vessels (gravity assists). - Early mobilization in burns and post-op patients promotes circulation and healing; prevents complications (DVT, pneumonia, pressure ulcers). 7. **Monitor for Complications:** - Acute kidney injury (from sustained hypoperfusion → prerenal azotemia → oliguria → ↑ creatinine). - Compartment syndrome (in trauma with severe edema; risk of rhabdomyolysis and acute kidney injury; may require fasciotomy). - Disseminated intravascular coagulation (DIC) in sepsis; manifests as bleeding, thrombosis, low platelets, prolonged PT/aPTT. - Multi-organ dysfunction syndrome (MODS) in prolonged shock. **Clinical Scenario (Philippine Context):** A 45-year-old farmer is brought to a rural health center with 30% BSA thermal burns (house fire) 2 hours ago. Vitals: BP 90/60 (hypotensive), HR 120, RR 26, temp 38°C. Urine output: 15 mL in past 2 hours (oliguria). Skin is red/blistered, edematous. The nurse calculates Parkland formula: 4 mL × %BSA × kg body weight = 4 × 30 × 70 = 8,400 mL total in 24 hours; half (4,200 mL) in first 8 hours, then 4,200 mL over next 16 hours. Establishes large-bore IV (18-gauge); begins rapid infusion per protocol. Goal: restore urine output to 30–50 mL/hr (sign of adequate perfusion). On day 3, as edema begins to resolve and urine output increases to 80 mL/hr, fluid rate is reduced to prevent pulmonary edema during reabsorption phase.

Shock is a life-threatening state of **inadequate tissue perfusion and cellular oxygenation** resulting in anaerobic metabolism, cellular dysfunction, and organ failure. It is one of the most critical conditions encountered in acute care and emergency settings. Understanding shock pathophysiology enables rapid triage, assessment, and intervention per NCM protocols. **Definition and Pathophysiology:** Shock occurs when: 1. Circulating blood volume is inadequate (hypovolemic shock). 2. The heart fails to pump effectively (cardiogenic shock). 3. Peripheral vascular resistance is critically reduced (distributive shock). 4. Blood flow is obstructed (obstructive shock). In all cases, **tissue perfusion pressure (CPP = Mean Arterial Pressure − CVP) is insufficient** to deliver oxygen to tissues. Cells switch from aerobic to anaerobic metabolism, producing lactic acid, depleting ATP, and triggering cell death cascade. **Early recognition and intervention in the compensatory stage—before organ failure—is critical for survival.** **Classification of Shock:** **1. Hypovolemic Shock** (Most Common; ~45% of shock cases) Cause: Loss of circulating blood volume (>15–20% of blood volume) Mechanisms: - **Hemorrhage**: Trauma (external bleeding, internal bleeding in abdomen/pelvis), GI bleeding (ulcer, varices), surgical blood loss. - **Dehydration**: Severe diarrhea (cholera, viral gastroenteritis), vomiting, diaphoresis (fever), reduced intake, diabetes insipidus, osmotic diuresis (uncontrolled DM). - **Third-spacing**: Burns, sepsis, pancreatitis, bowel obstruction (covered in previous section). - **Renal or GI losses**: Polyuria from DM, loop diuretics, nephrotic syndrome. Example: 30-year-old in MVA with femur fracture → intra-abdominal bleeding + external bleeding → blood loss 2–3 L → hypovolemic shock. Without transfusion and surgical hemostasis, death follows. **2. Cardiogenic Shock** (Second Most Common; ~20% of shock cases) Cause: Heart failure to pump effectively Mechanisms: - **Acute myocardial infarction** (most common cardiogenic cause): Large anterior MI → left ventricular dysfunction → ↓ cardiac output → pulmonary edema + systemic hypoperfusion. Shock develops in 5–15% of MI patients and carries ~50% mortality despite intervention. - **Acute heart failure**: Decompensated due to infection (myocarditis), toxins (alcohol, certain chemotherapy), arrhythmias (atrial fibrillation, ventricular tachycardia), acute valvular regurgitation (papillary muscle rupture post-MI, endocarditis). - **Dysrhythmias**: Severe bradycardia (complete heart block), tachycardia (VT, SVT) with rapid rate limiting diastolic filling time → ↓ cardiac output. - **Pulmonary embolism**: Large PE obstructs RV outflow → RV dysfunction → ↓ left ventricular filling → ↓ cardiac output (overlaps with obstructive shock). - **Cardiac tamponade**: Fluid accumulation in pericardium (trauma, cancer, infection) compresses heart → ↓ ventricular filling → ↓ cardiac output (obstructive component). Distinguishing feature: **Pulmonary edema often present** (fluid backs up into lungs from ↑ left ventricular end-diastolic pressure). **3. Distributive Shock** (Third Most Common; ~25% of shock cases) Cause: **Massive vasodilation** causing maldistribution of blood volume (central pooling of blood, reduced perfusion pressure despite adequate or high total blood volume) Mechanisms: - **Septic shock** (most common distributive type): Infection (bacterial, viral, fungal) → endotoxin/exotoxin release → immune cell activation → massive release of TNF-α, IL-1, IL-6, nitric oxide, prostaglandins → systemic vasodilation + capillary leak (third-spacing) + myocardial depression → ↓ SVR + ↓ cardiac output. Early septic shock presents as warm shock (warm extremities, high cardiac output, low SVR); late septic shock becomes cold (cool extremities, low cardiac output). Common sources: pneumonia, urinary tract infection, intra-abdominal infection (perforated viscus, appendicitis), wound infection. High mortality (20–40%) even with treatment. - **Anaphylactic shock**: Type I hypersensitivity reaction (IgE-mediated, immediate). Allergen exposure (peanuts, shellfish, antibiotics especially penicillin, blood products, latex, insect venom) → mast cell degranulation → massive histamine, tryptase, leukotrienes release → systemic vasodilation + bronchospasm + angioedema + capillary leak. Onset: seconds to minutes. Signs: urticaria, pruritis, flushed skin, angioedema (face, tongue, airway), bronchospasm (stridor, wheezing, dyspnea), hypotension, tachycardia, altered mental status. **Medical emergency** requiring immediate epinephrine IM (0.3–0.5 mg of 1:1000 solution; repeat q5–15 min if needed). IV access and antihistamines/corticosteroids are supportive. Death can occur within minutes from airway obstruction or profound shock. - **Neurogenic shock**: Acute spinal cord injury (cervical/high thoracic) → loss of sympathetic vasomotor tone → massive vasodilation → ↓ SVR + ↓ heart rate (unopposed parasympathetic tone via vagus nerve) → profound hypotension. **Classic feature: BRADYCARDIA with warm, dry skin (NOT tachycardia and cool skin like other shock types).** Temporary; resolves over weeks as spinal shock phase ends and autonomic reflexes below injury recover. Distinguish from septic shock (bradycardia + warm skin also seen in early septic shock, but fever/elevated WBC/leukocytosis help differentiate). - **Toxic shock**: Staphylococcal or streptococcal exotoxins (e.g., TSST-1) → similar mechanism to septic shock. Rapidly progressive; multi-organ failure. Associated with tampons, wound infection, post-op. Mortality ~30%. **4. Obstructive Shock** (~10% of shock cases) Cause: **Physical obstruction** to blood flow preventing adequate cardiac output Mechanisms: - **Cardiac tamponade**: Pericardial fluid under pressure compresses ventricles → ↓ diastolic filling → ↓ cardiac output. Causes: trauma (hemopericardium), malignancy (pericardial effusion), infection (pericarditis), post-cardiac surgery. Signs: Beck's triad (hypotension, muffled heart sounds, elevated JVD) + pulsus paradoxus (systolic BP drop >10 mmHg on inspiration). Diagnosis: Echocardiography; treatment: pericardiocentesis (needle drainage) or surgical drain. - **Tension pneumothorax**: Collapsed lung from trauma or barotrauma → mediastinal shift → ↓ venous return to right atrium → ↓ cardiac output + airway compromise. **Medical emergency.** Signs: severe dyspnea, hypoxia, hypotension, elevated JVD (NOT reduced as in simple pneumothorax), tracheal deviation (away from pneumothorax), unilateral breath sounds absent. Treatment: **immediate needle decompression** (large-bore needle into 2nd intercostal space midclavicular line) followed by chest tube. Do not wait for X-ray. - **Massive pulmonary embolism** (PE): Large blood clot in pulmonary artery → ↑ RV afterload → RV dysfunction → ↓ left ventricular filling → ↓ cardiac output. Signs: acute dyspnea, chest pain (pleuritic), tachycardia, hypoxia, hypotension, elevated JVD (RV strain), right-sided S3 gallop. D-dimer elevated; CT angiography (CTA) confirms diagnosis. Treatment: anticoagulation (LMWH, unfractionated heparin), thrombolysis in massive PE with hemodynamic compromise, IVC filter if anticoagulation contraindicated. - **Aortic dissection**: Tear in aortic intima → blood dissects between media layers → loss of perfusion pressure to distal organs. Hypertensive patient with sudden severe chest/back pain, BP differential between arms, pulse differentials. Diagnosis: CT angiography or transesophageal echo (TEE). Treatment: BP control, beta blockers (reduce aortic shear), surgical repair type A; medical management type B. --- **Stages of Shock:** Shock progresses through four stages; early intervention during compensatory stage can prevent progression to irreversible shock. **Stage 1: Initial (Compensatory) Stage** *Timeframe:* Minutes to hours after insult *Cellular events:* - Tissue perfusion pressure begins to fall; cells switch to anaerobic metabolism. - Lactic acid accumulates (lactic acidosis begins but subtle). - ATP depletion and cell dysfunction begin at subcellular level. - Yet, **compensatory mechanisms are still intact and effective**—this is the critical window for intervention. *Clinical manifestations:* - **Often minimal or subtle—many patients appear only mildly affected or "not that sick."** - Mild anxiety or restlessness (earliest sign of cerebral hypoperfusion; **do not dismiss this**). - Mildly elevated heart rate (100–120 bpm; compensatory to maintain cardiac output as BP begins to drop). - Slightly elevated respiratory rate (tachypnea from mild acidosis). - Skin may be normal, slightly cool, or with slight pallor. - Blood pressure may be **normal or only slightly reduced**; narrow pulse pressure (BP 100/90 instead of 120/80). - Urine output mildly reduced but often still >30 mL/hr. - Mental status normal to slightly anxious. *Lab findings:* - Serum lactate mildly elevated (2–4 mmol/L; normal <2). - Mild metabolic acidosis (pH 7.30–7.35; HCO3 18–21). - Mild hyperglycemia (stress hormones). *Critical nursing point:* **This is the best time to intervene.** If the compensatory mechanisms are overwhelmed (continued bleeding, worsening infection, inadequate resuscitation), shock progresses. Early recognition requires a high index of suspicion: a restless, slightly tachycardic patient who "feels off" may be in early shock. Start IV access, fluids, oxygen, and notification of physician immediately per NCM protocols. Do not wait for obvious signs. **Stage 2: Compensatory (Shock) Stage** *Timeframe:* Hours after initial stage; what is often called "compensatory shock" *Cellular events:* - Anaerobic metabolism accelerating; lactate levels rising significantly. - Metabolic acidosis worsening (pH <7.30, HCO3 <18). - ATP depletion → failure of Na+/K+ ATPase → cell edema, leakage of intracellular K+. - Still reversible if perfusion restored. *Clinical manifestations:* - **Anxiety, restlessness, agitation** (cerebral hypoperfusion). - **Tachycardia: HR 100–140 bpm** (often the most prominent sign; compensatory to increase cardiac output). - **Tachypnea: RR 20–30+** (from acidosis and hypoxemia; lungs attempting to blow off CO2 to raise pH). - **Cool, clammy, pale skin** (periphery: vasoconstriction shunting blood to vital organs; diaphoresis from sympathetic activation). - **Slightly reduced blood pressure: 90–100 mmHg systolic** (still present but low; some sources define shock as SBP <90, but shock can occur with higher BPs in young, athletic individuals with high baseline BP; look for *downward trend*). - **Oliguria: urine output <30 mL/hr** (kidneys hypoperfused; prerenal azotemia developing). - **Delayed capillary refill >2 seconds** (poor peripheral perfusion). - **Mental status: altered** (confusion, lethargy; cerebral hypoperfusion); restlessness may give way to obtundation. - **Narrowed pulse pressure** (e.g., 95/75 instead of 120/80; systolic-diastolic difference narrowed). *Lab findings:* - Serum lactate elevated (4–8+ mmol/L). - Metabolic acidosis: pH 7.20–7.30, HCO3 12–18, anion gap metabolic acidosis. - Hyperglycemia (stress hormones). - Hematocrit elevated in hemorrhage (hemoconcentration). - BUN/creatinine ratio elevated (prerenal azotemia from hypoperfusion). *Outcomes with intervention:* - If fluids, oxygen, vasopressors, and definitive treatment (stop bleeding, antibiotics, etc.) are given now, **recovery is likely**. - Organ function is compromised but reversible. *Outcomes without intervention:* - Shock progresses to stage 3 (progressive). **Stage 3: Progressive (Decompensatory) Stage** *Timeframe:* Hours to ~24 hours after shock onset (depending on type and intervention) *Cellular events:* - Severe ATP depletion; cellular dysfunction widespread. - Lysosomal rupture → release of intracellular enzymes → cell death (necrosis). - Inflammatory cascade amplified; cytokine storm (TNF, IL-1, IL-6, IL-8) causing widespread capillary leak, DIC, SIRS. - Mitochondrial dysfunction; further metabolic acidosis. - Multi-organ dysfunction begins (lungs, heart, kidneys, GI tract, brain). *Clinical manifestations:* - **Profound hypotension: SBP <80 mmHg** despite IV fluids and even vasopressors. - **Severe tachycardia: HR >140 bpm** (may plateau or decline as myocardial failure worsens). - **Severe tachypnea: RR >30** (Kussmaul respirations; deep, labored, from severe acidosis). - **Altered mental status: unresponsiveness, unrousable** (cerebral hypoperfusion, hypoxemia, acidosis). - **Severe oliguria: urine output <10 mL/hr or anuria** (acute kidney injury from sustained hypoperfusion). - **Skin mottled, cyanotic, cold** (severe peripheral hypoperfusion). - **Weak or absent pulses** (profound hypotension; difficult to palpate). - **Signs of organ failure**: - **Lungs**: Pulmonary edema (ARDS—acute respiratory distress syndrome from capillary leak and inflammation), crackles, SpO2 low despite high-flow oxygen. - **Heart**: Dysrhythmias (from acidosis, hypoxemia, K+ shifts), heart sounds distant or inaudible, evidence of cardiogenic shock (elevated JVD, hepatomegaly). - **Kidneys**: Oliguria/anuria, rising creatinine (acute tubular necrosis from sustained hypoperfusion). - **GI**: Abdominal distension, paralytic ileus (slowed motility from hypoperfusion), GI bleeding (stress ulcers), possible perforation. - **Coagulation**: Signs of DIC—bleeding (petechiae, ecchymosis, mucosal bleeding), thrombosis, low platelets, elevated PT/aPTT, elevated D-dimer, low fibrinogen. *Lab findings:* - Serum lactate severely elevated (>8 mmol/L); lactate >4 mmol/L associated with high mortality. - Severe metabolic acidosis: pH <7.20, HCO3 <12, large negative base deficit. - Severe hyperglycemia (stress hormones, organ dysfunction). - Elevated creatinine, elevated BUN (acute kidney injury). - Elevated LFTs (liver hypoperfusion). - Elevated troponin (myocardial necrosis). - Low platelets, prolonged PT/aPTT, low fibrinogen, elevated D-dimer (DIC). - Elevated WBC (stress response); if infection, left shift (bands, metamyelocytes). *Outcomes:* - Even with aggressive intervention (fluids, pressors, ICU support), mortality is high (>50% depending on shock type and underlying cause). - Multi-organ dysfunction progresses; MODS (multiple organ dysfunction syndrome) develops. **Stage 4: Irreversible (Refractory) Stage** *Timeframe:* Late stage; if reached, prognosis is essentially hopeless *Cellular events:* - Massive cell death; widespread necrosis. - Organ architecture destroyed; cellular function irreversible. - Myocardial necrosis; inability to respond to any intervention. - Severe inflammatory cascade; DIC consuming coagulation factors and platelets. *Clinical manifestations:* - **Profound unresponsiveness** (comatose). - **No response to fluids or vasopressors** (blood pressure cannot be maintained despite high-dose catecholamines). - **Severe bradycardia or no palpable pulse** (impending cardiac arrest). - **Severe metabolic acidosis (pH <7.0) not responsive to IV bicarbonate**. - **Anuric renal failure** (no urine output despite fluids). - **DIC** with active bleeding and thrombosis. - **Absent breath sounds or severe respiratory failure** despite mechanical ventilation. - **Signs of multi-organ failure and death.** *Outcomes:* - Death is imminent; recovery is not possible. Supportive care and end-of-life counseling are appropriate. In some systems, DNR (Do Not Resuscitate) status is clarified; in others, resuscitation may continue until cardiac arrest is irreversible. --- **Priority Nursing Management of Shock (Applicable Across All Types; NCM Levels II–III):** The ABCs and rapid intervention are paramount: **A — Airway & Breathing:** 1. Ensure patent airway; clear secretions, foreign bodies. 2. Administer **high-flow oxygen** (non-rebreather mask, 10–15 L/min, target SpO2 >94–95%) to maximize oxygen delivery. In severe shock, intubation and mechanical ventilation may be needed. 3. Position patient supine (unless respiratory distress/pulmonary edema, then semi-Fowler's). 4. Monitor respiratory status: rate, depth, SpO2, signs of respiratory distress (stridor, retractions, nasal flaring). 5. Prepare for intubation if respiratory failure develops (altered mental status, inability to protect airway, severe hypoxemia despite oxygen, high respiratory effort). **B — Breathing/Circulation (continued):** **C — Circulation:** 1. **Obtain IV access immediately:** Establish at least two large-bore IVs (18-gauge or larger) for rapid fluid infusion. In massive hemorrhage, central line may be placed for pressors. 2. **Rapid fluid resuscitation** (initial management for hypovolemic, distributive, neurogenic shock; careful in cardiogenic shock): - **First fluid: Isotonic crystalloid** (0.9% NaCl or Lactated Ringer's), available in all Philippine facilities. - **Bolus protocol:** 500 mL–1 L IV bolus over 15–30 minutes; reassess response (BP, HR, mental status, urine output). If improvement minimal, repeat bolus; if no improvement after 2–3 boluses, consider other causes or need for vasopressors + ICU care. - **Maintenance after boluses:** Once initial perfusion restored, continue at ~100–150 mL/hr, adjusting based on ongoing losses and urine output (goal UOP 30–50 mL/hr, or 0.5 mL/kg/hr). - **Blood products in hemorrhage:** Type O negative (universal donor) blood if cross-match not available; once type & cross done, type-specific blood. Target hemoglobin 7–8 g/dL in acute hemorrhage (transfuse if Hgb <7 or ongoing hemodynamic instability despite fluids). - **Special consideration: Cardiogenic shock** — Give fluids cautiously (fluid overload → pulmonary edema); small boluses (250 mL), reassess frequently. May need diuretics and vasopressors (inotropes) rather than fluids. 3. **Vasopressors** (if hypotension persists despite fluids): - **Norepinephrine** (most commonly used; alpha- and beta-adrenergic effects; maintains BP and perfusion). - **Dopamine** (dose-dependent: low dose renal/visceral vasodilation; high dose vasoconstriction). - **Epinephrine** (alpha- and beta-effects; used if dopamine/norepinephrine inadequate, or immediately in anaphylaxis IM). - **Vasopressin** (selective vascular effects; used in refractory septic shock). - Vasopressors are titrated to target MAP >65 mmHg (critical organs perfuse). In limited-resource Philippine settings, norepinephrine may not be available; in such cases, dopamine or epinephrine are alternatives. Standard practice: establish IV access, give fluids, notify physician immediately to arrange transfer to facility with ICU and pressors. 4. **Position:** Supine with **lower extremities elevated 30 degrees** (modified Trendelenburg; gravity assists venous return without compromising cerebral perfusion). Avoid full Trendelenburg (head below feet)—increases intracranial pressure and worsens respiratory compromise. 5. **Elevate feet on pillows; NOT steep head-down angle** to prevent aspiration risk and cerebral edema in already hypoperfused patient. **D — Disability (Mental Status):** 1. Assess mental status and Glasgow Coma Scale (GCS). 2. Altered mental status is a sign of shock; frequently indicates cerebral hypoperfusion. 3. Reorient frequently; provide reassurance (patient anxiety worsens sympathetic response). 4. Monitor for seizures (hypoxemia, acidosis, hypoglycemia in shock can precipitate seizures). **E — Exposure/Environment:** 1. Keep patient warm (cover with blankets) to prevent hypothermia, which worsens acidosis and coagulopathy. Avoid excessive exposure during assessment. 2. Remove wet or contaminated clothing. 3. Continue assessment and reassessment. **Ongoing Nursing Actions (NCM Levels II–III):** 1. **Continuous monitoring:** - Vital signs: q5–15 min initially in shock; more frequently if unstable. - Cardiac monitor: dysrhythmias common; document and treat per ACLS protocols. - Pulse oximetry continuous (SpO2 target >94%). - Urine output: Foley catheter for accurate measurement; q1h in acute phase; target 30–50 mL/hr (0.5 mL/kg/hr). - If available (ICU setting): CVP (central venous pressure; target 8–12 mmHg), arterial line for continuous BP and serial ABGs, ScvO2 (central venous oxygen saturation). - Capillary refill, skin color/temperature, peripheral pulses. 2. **Laboratory monitoring (repeat as indicated):** - ABG or venous blood gas (assess pH, HCO3, pO2, pCO2, lactate); repeat after initial resuscitation and q2–4h if ongoing shock. - CBC (hemoglobin trend in hemorrhage; WBC in infection/sepsis). - BMP (electrolytes, glucose, creatinine, BUN; hypokalemia and hyperkalemia both dangerous in shock). - Lactate (marker of tissue hypoperfusion; elevated lactate >4 mmol/L associated with poor prognosis; should trend down with successful resuscitation). - Coagulation studies (PT, aPTT, platelets, D-dimer, fibrinogen) if DIC suspected; troponin if cardiogenic shock; LFTs if septic shock or liver involvement. - Blood cultures before antibiotics if septic shock suspected. 3. **Identify and treat the cause:** - **Hypovolemic:** Stop bleeding (apply direct pressure, tourniquet for limb hemorrhage; surgery for internal bleeding); restore volume (IV fluids, blood products). - **Cardiogenic:** 12-lead ECG to identify MI (ST-elevation MI needs emergency PCI/thrombolysis); echo for ejection fraction; troponin; cardiac enzymes; treat dysrhythmias; consider inotropes, diuretics per physician. - **Distributive (septic):** Blood cultures; broad-spectrum antibiotics (within 1 hour per Surviving Sepsis guidelines); source control (drainage, debridement); fluid resuscitation; vasopressors if needed. - **Distributive (anaphylactic):** Immediately stop allergen exposure (e.g., stop transfusion, stop antibiotics); epinephrine IM 0.3–0.5 mg of 1:1000 solution q5–15 min as needed; IV access; fluids; antihistamines (diphenhydramine); corticosteroids (methylprednisolone). - **Obstructive:** Urgent decompression (pericardiocentesis for tamponade, needle decompression for tension pneumothorax, thrombolysis for massive PE). 4. **Prevent complications:** - Stress ulcer prophylaxis (H2 blocker or PPI) to prevent GI bleeding. - DVT prophylaxis (sequential compression devices; anticoagulation if not contraindicated). - Catheter care (aseptic technique; remove central lines as soon as possible to prevent infection). - Glucose control (insulin infusion; target 140–180 mg/dL; avoid hypoglycemia <100 mg/dL). - Nutritional support (enteral feeding if possible). - Pain management (opioids; avoid excessive doses that suppress respiration). - Infection prevention (hand hygiene, sterile technique). 5. **Communication:** - Keep patient and family informed of status, interventions, and prognosis; provide emotional support. - Notify physician/ICU team immediately; anticipate transfer if resources inadequate at current facility. - Document interventions and response; communicate clearly in handoff. **Type-Specific Nursing Considerations:** **Hypovolemic Shock:** - Monitor for ongoing bleeding; assess wound/stool/urine for blood. - Crossmatch blood; prepare for transfusion. - Keep NPO (may need surgery). - Position: Supine with legs elevated (modified Trendelenburg). **Cardiogenic Shock:** - Monitor for pulmonary edema (crackles, orthopnea, frothy sputum); may need diuretics or intubation. - Fluid cautiously (may worsen pulmonary edema). - Monitor for dysrhythmias (MI, heart failure). - 12-lead ECG; troponin; prepare for interventions (PCI, IABP—intraaortic balloon pump, if available). **Septic Shock:** - Rapid antibiotics (within 1 hour per Surviving Sepsis Campaign guidelines); broad-spectrum initially pending cultures. - Source control: drainage of abscess, debridement of infected tissue, removal of infected lines. - Fluid resuscitation (crystalloid); monitor for pulmonary edema (septic patients often need aggressive fluid resuscitation). - Glucose control (insulin infusion; hyperglycemia worsens outcomes). - Monitor lactate (should trend down; persistent elevation suggests ongoing inadequate perfusion). **Anaphylactic Shock:** - **Immediate epinephrine IM:** 0.3–0.5 mg of 1:1000 solution q5–15 min until improvement. - Stop allergen (transfusion, antibiotic, etc.). - IV access; fluids; IV antihistamines and corticosteroids. - Observe closely (biphasic anaphylaxis can occur hours later). - Educate on allergen avoidance; prescribe EpiPen for future exposures. **Neurogenic Shock:** - Expect bradycardia (different from other shock types); do NOT treat as asymptomatic bradycardia; heart rate is appropriate for decreased metabolic demand. - Fluids cautiously (may overload with peripheral vasodilation; monitor CVP if available). - Immobilize spine (if spinal cord injury suspected; avoid further trauma). - Maintain normothermia (injury impairs thermoregulation). - Monitor for progression of neurologic deficit; urgent neurosurgical evaluation. **Obstructive Shock:** - Cardiac tamponade: Prepare patient for pericardiocentesis or surgical drainage. - Tension pneumothorax: Immediate needle decompression (large-bore needle, 2nd ICS midclavicular), then chest tube. - Massive PE: Anticoagulation (if no contraindication); thrombolysis (tPA); prepare for possible thrombectomy or embolectomy in ICU. **Clinical Scenario (Philippine Context):** A 32-year-old construction worker is brought to rural hospital following crush injury to abdomen/legs in building collapse. Arrived 4 hours post-injury. Vitals: BP 98/65, HR 118, RR 22, SpO2 92% on room air, temp 36.8°C (no fever yet), Foley output 25 mL in past hour. Patient anxious, restless. Abdomen firm, distended, with contusions. Pelvis stable. Exam reveals crush injury to bilateral lower extremities with compartmental swelling but intact skin. Initial lab: Hgb 10.5 g/dL (baseline unknown), WBC 14,000, creatinine 1.4 (baseline normal), K 5.2 (mildly elevated; crush injury releases intracellular K), pH 7.32, HCO3 18, lactate 4.2. (Patient is in compensatory shock with early rhabdomyolysis from crush injury.) Nursing actions (NCM II–III): 1. Place on high-flow oxygen (non-rebreather mask, 10 L/min; target SpO2 >95%). 2. Establish two large-bore IVs; blood work repeated; crossmatch for possible transfusion. 3. Aggressive IV fluid resuscitation: Parkland formula for burns does not apply here, but crush injury causes massive third-spacing and rhabdomyolysis. Goal urine output is **higher than usual—aim for 200–300 mL/hr initially** (helps flush myoglobin from renal tubules, preventing acute kidney injury). Bolus 1 L LR over 20 min; reassess BP (should improve toward 110+), HR (should decrease toward 100–110). Continue infusion at calculated rate to achieve target UOP. 4. Foley catheter with target UOP 200 mL/hr; monitor urine color (myoglobinuria—dark/cola-colored urine is ominous sign of rhabdomyolysis; should clear with fluid resuscitation). 5. Monitor for compartment syndrome (pain out of proportion to exam, pain on passive stretch of leg muscles—sign of increased compartment pressure; needs urgent fasciotomy). Given significant swelling, compartment pressure measurement or clinical assessment for fasciotomy indicated. 6. Monitor K (hyperkalemia from crush; peaked T waves on ECG; risk of cardiac dysrhythmia); treat with calcium gluconate (membrane stabilization), insulin + glucose, albuterol if K >6 and ECG changes. 7. Monitor creatinine (may rise from rhabdo; maintain urine output to flush myoglobin and prevent acute tubular necrosis). 8. Pain management; keep NPO (may need OR for fasciotomy). 9. Continuous monitoring; consider transfer to facility with ICU capability if patient decompensates. 10. Once perfusion restored and shock resolving (BP >110, HR <100, urine output improved, lactate trending down), reduce fluid rate cautiously to prevent pulmonary edema in reabsorption phase (as in third-spacing recovery).