Physiological Adaptation: Managing Acute and Chronic Conditions
What you must understand
This domain asks you to manage the pathophysiology of common medical-surgical conditions. Know fluid and electrolyte imbalances: hyperkalemia (peaked T waves, muscle weakness), hypokalemia (flat T waves, arrhythmias, ileus), hyponatremia (confusion, seizures), and hypernatremia (thirst, neurologic changes). Know acid-base interpretation: respiratory acidosis from hypoventilation, respiratory alkalosis from hyperventilation, metabolic acidosis from diabetic ketoacidosis, diarrhea, or renal failure, and metabolic alkalosis from vomiting or diuretics.
Know the management priorities for diabetic ketoacidosis (fluids first, then insulin, monitor potassium), heart failure (daily weights, fluid restriction, assess for orthopnea and crackles), chronic obstructive pulmonary disease (low-flow oxygen targeting an appropriate saturation, pursed-lip breathing), and acute kidney injury (monitor output, potassium, and creatinine). Know the signs of increased intracranial pressure and the care of a client with a chest tube or tracheostomy.
Traps to watch
- In DKA, give fluids before insulin, and watch potassium as insulin drives it into cells.
- Daily weight is the most reliable indicator of fluid status, not intake and output alone.
- Do not withhold oxygen out of fear of hypoxic drive; titrate to target saturation.
- Match the symptom to the electrolyte rather than memorizing lists separately.
Rule of thumb
When a scenario presents multiple abnormal findings, treat the one that threatens airway, breathing, or circulation first, then correct the underlying cause. Reassess after every intervention.
Worked example
A client with DKA has a glucose of 480 mg/dL, pH 7.20, and a potassium of 3.1 mEq/L. The priority is fluid resuscitation and potassium replacement before insulin, because insulin shifts potassium into cells and can precipitate a dangerous hypokalemia.