Medical-Surgical Nursing (Adult Health)
What this domain tests
Medical-Surgical Nursing (Adult Health) covers fluid, electrolyte, and acid-base balance, perioperative care, and management of common adult conditions such as myocardial infarction, heart failure, COPD, stroke, and diabetes.
Core rules
- Interpret ABGs in steps: pH, then PaCO2, then HCO3, then compensation. Uncompensated means pH outside range with one system shifted; compensated means pH near normal with both systems shifted.
- Potassium is the dangerous electrolyte: peaked T waves and widened QRS in hyperkalemia; flat T waves, U waves, and ileus in hypokalemia. Never give IV potassium by push.
- Postoperative fever has a timeline: atelectasis in the first 48 hours, infection later. Deep vein thrombosis is a separate cause of tachycardia and hypoxia.
- In acute coronary syndrome, give aspirin, nitroglycerin, oxygen only if hypoxic, and morphine for refractory pain; monitor for hypotension after nitrates.
- Stroke: sudden focal deficit, activate the stroke pathway, check glucose, avoid hypoxia and fever, and withhold aspirin until hemorrhage is excluded.
Worked example
ABG: pH 7.28, PaCO2 30 mmHg, HCO3 14 mEq/L. What is the interpretation? Reasoning: pH is acidemic, so the primary problem is acidosis. HCO3 is low, confirming metabolic acidosis. PaCO2 is low, the expected respiratory compensation. The values fit diabetic ketoacidosis or lactic acidosis; calculate the anion gap and treat the cause. Do not label it respiratory because the CO2 is abnormal.
Traps
- Calling any low pH respiratory without checking which buffer moved first.
- Giving bicarbonate before treating the underlying cause.
- Missing silent aspiration or delirium in older adults.
- Assuming a normal SpO2 excludes pulmonary embolism.