MEDSURG · Study guide
Medical-Surgical study guide
Medical-surgical nursing is the care of adult patients across every body system, and it is the largest slice of most NCLEX-style exams. Success comes from connecting pathophysiology to assessment: knowing which finding is an early warning, which is a late and ominous sign, and which one you act on before all the others.
This guide focuses on the cross-cutting frameworks — acid-base, fluids and electrolytes, oxygenation, perfusion — that let you reason about a scenario even when the specific disease is unfamiliar. Pair it with the topic quiz to practice prioritization under time pressure.
High-yield concepts
Read acid-base with ROME
For arterial blood gases, “Respiratory Opposite, Metabolic Equal” keeps directions straight: in respiratory disorders the pH and CO2 move in opposite directions, while in metabolic disorders the pH and bicarbonate move together. First decide acidosis vs. alkalosis from the pH, then find the driver (CO2 or HCO3), then check whether the other value has shifted to compensate.
Potassium is a cardiac electrolyte
Both high and low potassium threaten the heart. Hyperkalemia produces peaked T waves and can progress to lethal arrhythmias; hypokalemia produces flattened T waves, U waves, and increases digoxin toxicity risk. Any potassium abnormality with ECG changes is an emergency, and IV potassium is always diluted and infused slowly — never pushed.
Sodium tracks water and mental status
Sodium disturbances present neurologically because water shifts across the blood-brain barrier. Hyponatremia causes confusion, headache, and seizures; hypernatremia causes thirst, restlessness, and lethargy. Correcting sodium too quickly is itself dangerous, so the safe nursing focus is monitoring neuro status and following the ordered rate.
Chest pain: MONA is not the whole story
In suspected acute coronary syndrome, the priority is rapid assessment, a 12-lead ECG, oxygen if hypoxemic, aspirin, and pain control while troponin is drawn. Time is muscle: the sooner ischemia is identified and perfusion restored, the more myocardium survives. Nitroglycerin is withheld if the systolic pressure is low or the patient has taken a phosphodiesterase inhibitor.
COPD vs. asthma oxygen logic
Both cause airflow obstruction, but the exam tests different priorities. In an asthma attack, wheezing that suddenly disappears with a silent chest signals worsening obstruction, not improvement. In COPD, deliver oxygen to a target saturation rather than the highest possible flow, and recognize that the goal is adequate oxygenation, not a normal number.
Recognize sepsis early
Sepsis is a dysregulated response to infection that progresses to organ dysfunction. Early clues include fever or hypothermia, tachycardia, tachypnea, and altered mental status; a rising lactate and falling blood pressure signal deterioration. Early recognition, cultures before antibiotics, timely broad-spectrum antibiotics, and fluid resuscitation drive outcomes.
Diabetes emergencies: DKA vs. HHS
Diabetic ketoacidosis is more common in type 1 diabetes, develops quickly, and features high blood glucose, ketones, acidosis, and Kussmaul respirations with a fruity breath odor. Hyperosmolar hyperglycemic state is more common in type 2, develops slowly, and features very high glucose with profound dehydration but little or no ketosis. Both start with IV fluids, then insulin with careful potassium monitoring.
Increased intracranial pressure
Rising intracranial pressure shows a declining level of consciousness first — the earliest and most sensitive sign. The classic late Cushing’s triad (rising systolic pressure with a widening pulse pressure, bradycardia, and irregular respirations) is ominous. Keep the head of bed elevated around 30 degrees with the head midline, and avoid actions that spike pressure.
Common NCLEX-style traps
- “First” questions want the highest priority now — use ABCs and “unstable before stable,” not the task that is merely due next.
- A normalizing number is not always improvement: a suddenly silent chest, a slowing heart rate with rising ICP, or a “quiet” abdomen can each signal deterioration.
- Do not correct sodium, potassium, or glucose faster than ordered; the safe answer is usually to monitor and follow the prescribed rate, not to speed it up.
- Match the finding to the timeline — exams love to contrast an early, compensated sign with a late, decompensated one and ask which patient is more urgent.
- In ABG items, decide acidosis vs. alkalosis from the pH first; jumping straight to CO2 or bicarbonate without anchoring on pH leads to reversed answers.
Put it into practice
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Sources
- Harding MM, et al. Lewis’s Medical-Surgical Nursing. 12th ed. Elsevier; 2023.
- Evans L, et al. Surviving Sepsis Campaign: International Guidelines for Management of Sepsis and Septic Shock 2021. Critical Care Medicine. 2021.
- American Diabetes Association. Standards of Care in Diabetes—2024. Diabetes Care. 2024.
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