NLE Fundamentals of Nursing & the Nursing Process — Basic Oxygenation, Elimination & NutritionSummary

Oxygenation is a three-step process: (1) oxygen intake via the lungs (ventilation), (2) diffusion across the alveolar-capillary membrane (respiration), and (3) delivery to tissues via the cardiovascular system (perfusion). Normal arterial oxygen saturation (SpO₂) ranges 95–100%. Hypoxemia (SpO₂ <90%) indicates inadequate oxygen in the blood and demands immediate intervention. Early signs of hypoxia include restlessness, anxiety, tachypnea, tachycardia, and use of accessory muscles—these are often dismissed but are the earliest warning signs. Late signs (cyanosis, bradycardia, confusion, decreased consciousness) indicate severe hypoxia and risk of organ damage. Cyanosis is a late finding because it requires ~5 g/dL of deoxygenated hemoglobin; thus, a severely anemic patient may be profoundly hypoxic without visible cyanosis.

The choice of oxygen delivery device depends on the desired FiO₂ (fraction of inspired oxygen) and the patient's clinical condition. Nasal cannula (1–6 L/min) delivers 24–44% oxygen, is low-flow, comfortable, and allows eating/talking—ideal for mild hypoxemia or chronic conditions. Simple face mask (5–10 L/min, ~40–60% FiO₂) must maintain a minimum flow of 5 L/min to flush exhaled CO₂ and prevent CO₂ rebreathing. Partial rebreather mask (10–15 L/min, ~60–75%) and non-rebreather mask (10–15 L/min, ~80–95%) provide higher concentrations by allowing the patient to rebreathe a portion of exhaled gas containing oxygen. The Venturi mask delivers a precise, fixed FiO₂ (24–50%) regardless of patient breathing pattern, making it the device of choice for COPD patients who require controlled oxygen to maintain their hypoxic respiratory drive. Above 6 L/min, nasal cannula causes mucosal drying without significantly increasing FiO₂, so humidification is essential at higher flows.

Patent airway maintenance requires encouraging deep breathing, coughing, and use of incentive spirometry. Positioning (semi-Fowler's or high-Fowler's) maximizes lung expansion. When secretions accumulate, nasopharyngeal or endotracheal suctioning removes them but carries risk of hypoxia, tissue trauma, and dysrhythmias. Safe suctioning technique includes: (1) hyperoxygenation before suctioning (pre-oxygenation), (2) applying suction only on catheter withdrawal (not insertion), (3) limiting each pass to 10–15 seconds, and (4) allowing rest periods between passes. Sterile technique is mandatory to prevent infection. This is especially important in Philippine settings where aspiration pneumonia and ventilator-associated pneumonia (VAP) are common hospital-acquired infections.

Bowel elimination patterns vary widely (3× per week to 3× per day is normal). Constipation—infrequent, hard, difficult-to-pass stool—is the most common GI complaint. It results from decreased fiber, inadequate fluids, immobility, medications (opioids, anticholinergics), and behavioral factors. Management is stepwise: (1) increase dietary fiber and fluids, (2) promote ambulation and activity, (3) establish regular toileting routines (e.g., after meals), and (4) use stool softeners (docusate) or bulk-forming laxatives (psyllium) as first-line. Fecal impaction occurs when a hard mass accumulates; paradoxically, liquid stool may leak around it (overflow incontinence), mimicking diarrhea. Digital removal may be necessary with a physician order. Diarrhea—frequent, loose, watery stools—risks dehydration and electrolyte imbalance (especially in children and elderly). Priority nursing actions: (1) oral rehydration solution (ORS per DOH guidelines), (2) replacement of electrolytes, (3) skin care to prevent excoriation, and (4) identification of cause (infectious, medication-induced, lactose intolerance, IBS). In the Philippines, DOH protocols recommend ORS plus zinc supplementation for acute diarrhea in children under 5 years, proven to reduce duration and severity.

Enemas introduce fluid into the colon to stimulate evacuation. A cleansing enema (tap water, normal saline, or soapsuds) triggers peristalsis and bowel evacuation; a retention enema (oil-based) softens stool without immediate evacuation. Correct technique: position the patient in left lateral (Sims') position to follow the anatomic curve of the colon; insert the tube 7–10 cm in adults (less in children); raise the solution container 30–45 cm above the anus to allow gravity flow; instill slowly (stop if cramping occurs). The patient retains the solution 5–10 minutes for a cleansing enema or 30+ minutes for oil retention. Proper positioning and slow instillation reduce trauma and discomfort. Enemas are contraindicated in certain conditions (acute abdominal pain, recent abdominal surgery) and should be ordered by a physician.

Normal adult urine output is approximately 1,500 mL per day, with an acceptable minimum of ~30 mL/hour—a key marker of adequate renal perfusion. Output <30 mL/hr must be reported as it may indicate hypovolemia, shock, or renal dysfunction. Urinary catheterization bypasses the urethra and deposits urine directly into the bladder via an indwelling (Foley) catheter or intermittent straight catheter. Strict sterile technique is essential (surgical asepsis). Key safety points: (1) use the smallest appropriate catheter size (e.g., 16–18 Fr for adults), (2) insert only after visualizing the urinary meatus, (3) inflate the balloon only after urine flows (confirming bladder placement—premature inflation risks urethral trauma), (4) secure the catheter to prevent traction, (5) keep the drainage bag below bladder level (gravity drainage and infection prevention), and (6) maintain a closed system (never break the connection between catheter and bag). Catheter-associated urinary tract infection (CAUTI) is the most common hospital-acquired infection in the Philippines and worldwide; duration of catheterization is the greatest risk factor. Remove catheters as soon as clinically appropriate. Female insertion depth is ~5–7.5 cm; male insertion is ~17–20 cm.

For patients able to void normally, nurses create an environment that supports micturition: provide privacy, allow normal positioning (sitting/standing for males, sitting for females), offer warm water over the perineum to stimulate the reflex, respond promptly to the urge to void, and provide a bedpan/urinal/commode at comfortable height. Running water (auditory stimulus) and relaxation techniques facilitate voiding. For incontinence, nursing interventions include pelvic-floor (Kegel) exercises, bladder training (scheduled voiding), and assessment of underlying causes (urge incontinence, stress incontinence, overflow, functional). Kegel exercises strengthen the external urethral sphincter and pubococcygeus muscle; the patient contracts these muscles for 5–10 seconds, then relaxes, repeating 10–20 times, 3–4 times daily for sustained benefit.

A nasogastric (NG) tube delivers nutrition, medications, or gastric decompression when a patient cannot eat orally. The NEX method measures insertion length: Nose → Earlobe → Xiphoid process. Mark this point on the tube. Position the patient in high-Fowler's; ask them to flex their head forward (chin to chest) and sip water as the tube passes, promoting esophageal entry and reducing airway intubation risk. If the patient coughs, chokes, or becomes cyanotic, the tube is in the airway—withdraw immediately and allow recovery before reinsertionPlacement verification is critical and must be done before every feeding or medication. The most reliable bedside method is checking the pH of gastric aspirate (typically ≤5; intestinal fluid pH is >6); measure external tube length against the marked insertion point. X-ray confirmation is the gold standard, especially after initial insertion. The old auscultation ('whoosh' test) is unreliable and no longer recommended alone. Secure the tube to prevent pressure on the nares and mark the insertion point daily to detect migration.

Enteral nutrition delivers formula directly to the GI tract when a patient cannot eat but has a functioning gut (nasogastric, gastrostomy, jejunostomy). Advantages include lower cost, fewer complications than parenteral nutrition, and preservation of gut integrity. Before each feeding: (1) verify tube placement (gastric pH, external tube length, X-ray if indicated), (2) check for gastric residual volume (amount of food remaining from prior feeding); hold and reassess if high per protocol to prevent vomiting and aspiration, (3) elevate head of bed 30–45° during feeding and for 30–60 minutes after to promote gastric drainage and prevent aspiration (the most serious complication), (4) administer feeding at room temperature to avoid GI distress, (5) flush the tube with 30–50 mL of water before and after feeding to maintain patency, (6) administer medications separately (liquid form preferred; do not crush enteric-coated or sustained-release tablets), flush between each medication. Monitor for complications: diarrhea (osmotic from formula concentration or due to medications like antibiotics), dehydration (monitor output, weight), hyperglycemia (especially in diabetic patients), and refeeding syndrome (severe electrolyte and fluid shifts in malnourished patients receiving rapid nutrition repletion—monitor potassium, phosphate, magnesium closely). Continuous feeding (via pump) is safer than bolus feeding, which carries higher aspiration risk.

Accurate I&O monitoring detects fluid imbalance (dehydration or fluid overload). Intake includes: oral fluids, food with high water content, fluids via feeding tube, IV fluids, and irrigants not withdrawn. Output includes: urine, vomitus, diarrhea, wound/drain output, and significant blood loss. Normal adult balance is ~2,000–2,500 mL intake and output per day. Fluid volume deficit (dehydration) presents with thirst, dry mucous membranes, decreased skin turgor, concentrated/dark-colored urine, weight loss, tachycardia, and hypotension (late sign of severe dehydration). Management: increase oral fluids, administer IV fluids per order, and monitor. Fluid volume overload manifests as peripheral edema, pulmonary crackles, distended neck veins, weight gain, hypertension, and shortness of breath. Management: restrict fluids and sodium, administer diuretics per order, elevate extremities, monitor. Daily weight at the same time on the same scale in similar clothing is the most accurate indicator of fluid status (1 kg fluid gain/loss ≈ 1 L of fluid). A weight gain >1 kg/day or weight loss >0.5 kg/day warrants investigation.

Nutrition comprises macronutrients (carbohydrates: 4 kcal/g, proteins: 4 kcal/g, fats: 9 kcal/g) and micronutrients (vitamins, minerals). Assessment includes: usual weight, current weight, BMI (18.5–24.9 normal; <18.5 underweight; 25–29.9 overweight; ≥30 obese), dietary intake, serum albumin (marker of visceral protein; normal >3.5 g/dL; <2.5 indicates significant malnutrition), and prealbumin (shorter half-life than albumin; more sensitive to acute changes). Wound healing requires adequate protein, vitamin C (collagen synthesis), and zinc (immune function and epithelialization); deficiencies delay healing. The Philippine Department of Health promotes the Pinggang Pinoy model—a visual food plate showing recommended proportions: 1/4 grains, 1/4 protein, 1/2 fruits and vegetables. Therapeutic diets modify nutrient content for disease management: low-sodium (hypertension, heart failure, kidney disease), carbohydrate-controlled (diabetes), renal (reduced protein and potassium for CKD), high-fiber (constipation prevention), low-residue (before GI procedures or in inflammatory bowel disease). Nurses assess nutritional status, assist with feeding, monitor tolerance, and provide health teaching aligned with local food availability and cultural preferences.

Oxygen supports combustion; therefore, strict safety precautions are essential in all settings. Post 'Oxygen in Use' signs, ensure no smoking or open flames, avoid petroleum-based products (petroleum jelly, oils) on face or nose, and maintain proper storage. In patients with COPD or chronic hypercapnia, the primary respiratory drive is hypoxemia (not CO₂ as in healthy lungs); excessive oxygen (FiO₂ >40%) can blunt this drive, causing hypoventilation and CO₂ retention (hypercapnia). Management: use low-flow oxygen (nasal cannula 1–2 L/min) or the Venturi mask (precise FiO₂) titrated to a target SpO₂ of 88–92%. Do NOT withhold oxygen from a hypoxic patient; titrate carefully. In the Philippines, COPD prevalence is rising due to smoking and biomass fuel exposure, making this concept clinically relevant.

Wounds heal by primary intention (clean, approximated edges; e.g., surgical incision), secondary intention (open wound healing from the base upward; slower, more scarring), or tertiary intention (delayed closure; initial open healing, then closure later). Healing progresses through four overlapping phases: (1) hemostasis (immediate, stops bleeding via platelets and clotting), (2) inflammatory (0–3 days; redness, warmth, swelling, exudate; neutrophils and macrophages remove debris), (3) proliferative/granulation (3–21 days; new blood vessels form, fibroblasts lay collagen, epithelial cells migrate; wound appears red and moist), (4) maturation/remodeling (21 days to 2 years; collagen remodeling, scar tissue strengthens, eventually fades). Assessment includes: size (length, width, depth in cm), wound bed color (red = healthy granulation tissue, yellow = slough/dead tissue, black = necrotic eschar), amount and type of exudate (serous, serosanguinous, purulent), odor (foul = infection), surrounding skin (erythema, maceration, excoriation), and pain. Proper documentation with wound photography (where available) guides healing assessment.

Dressing changes must employ appropriate asepsis (sterile technique for open/surgical wounds, clean technique for chronic wounds). Cleansing method: irrigate with normal saline; clean from least contaminated to most contaminated areas (e.g., incision center outward, clean to dirty). Avoid cytotoxic agents (hydrogen peroxide, povidone-iodine) on healthy granulation tissue as these damage new tissue. Protect peristomal skin from excoriation using appropriate barrier products. Manage drains (Jackson-Pratt, Penrose) with sterile technique; measure and document output daily (initially bloody, gradually serous). Support healing through: adequate nutrition (protein, vitamin C, zinc), blood perfusion (avoid pressure, promote ambulation), moisture balance (moist environment promotes epithelialization but excessive moisture causes maceration), and infection prevention (aseptic technique, hand hygiene). Assess for complications: infection (increasing redness, warmth, purulent drainage, fever, elevated WBC), dehiscence (edges separate; may indicate infection or excessive tension), and evisceration (organs protrude through wound—a surgical emergency). Evisceration management: cover immediately with a sterile, saline-moistened dressing, keep patient NPO, position in low-Fowler's with knees flexed (minimizes abdominal tension), notify surgeon immediately.

Acute diarrhea in Filipino children is a leading cause of morbidity and mortality, especially in infants and young children in resource-limited areas. The DOH Integrated Management of Neonatal and Childhood Illness (IMNCI) guidelines recommend: (1) oral rehydration solution (ORS) as first-line therapy to replace lost fluids and electrolytes, (2) zinc supplementation (10 mg daily for 10–14 days in children >6 months; 5 mg for <6 months) to reduce duration and severity of diarrhea and prevent future episodes, (3) continued feeding (even during diarrhea; breastfeeding continues), (4) assessment of dehydration severity (no signs, some dehydration, severe dehydration) guiding IV rehydration decisions, and (5) identification of cause (viral, bacterial, parasitic, dietary). Breastfed infants should continue breastfeeding; formula-fed infants may receive lactose-free formula temporarily if lactose intolerance is suspected. Skin care (barrier creams) prevents diaper dermatitis.