Physiological Integrity: Physiological Adaptation
Physiological Adaptation
This domain tests pathophysiology and management of acute and chronic illness: fluid and electrolyte imbalance, acid-base, shock, sepsis, respiratory failure, cardiac events, diabetes emergencies, renal failure, and burns. The exam expects you to connect the underlying process to the priority intervention.
Core rules
- In shock, perfusion fails. Priorities are airway, oxygenation, IV access, fluid resuscitation, and identifying the cause.
- Sepsis: infection plus organ dysfunction. Obtain cultures before antibiotics if it does not delay treatment; give broad-spectrum antibiotics and fluids promptly.
- DKA: hyperglycemia, ketosis, metabolic acidosis, and osmotic diuresis. Start with IV fluids, then insulin; monitor potassium closely because insulin drives potassium into cells.
- Acid-base: check pH, PaCO2, and bicarbonate. Respiratory disorders change CO2; metabolic disorders change bicarbonate.
- Burns: airway first, then fluid resuscitation using weight-based formulas, and monitor for compartment syndrome.
- Heart failure: assess for crackles, dyspnea, edema, and weight gain; position upright and administer oxygen and diuretics as ordered.
Worked example
A client with DKA has glucose 520 mg/dL, pH 7.22, bicarbonate 12 mEq/L, and potassium 5.2 mEq/L. The priority is IV fluid resuscitation, followed by an insulin infusion and frequent potassium monitoring. Insulin will lower potassium, so a fall is expected; replacing potassium prematurely without a level is unsafe, and giving insulin before fluids can worsen hypotension. The reasoning ties treatment to pathophysiology: dehydration and ketosis come first, and insulin shifts potassium.
Traps that cost marks
Giving insulin before fluids in DKA; ignoring potassium during insulin therapy; treating fever without assessing for sepsis; giving bicarbonate routinely; missing subtle early signs of shock.