Cardiovascular, Pulmonary, and Vascular Systems
Oxygen delivery and limitation
Cardiopulmonary questions ask you to interpret vital signs and exercise responses. Cardiac output equals heart rate times stroke volume; preload, afterload, and contractility determine stroke volume. During exercise, HR and systolic BP rise, diastolic BP changes little, and the arteriovenous oxygen difference widens. Obstructive lung disease (COPD, asthma) limits expiration; restrictive disease (fibrosis, kyphoscoliosis) limits expansion.
Concepts to name
- Angina and myocardial infarction: chest pain, diaphoresis, nausea; atypical presentations in women and diabetes.
- Heart failure: exertional dyspnea, orthopnea, paroxysmal nocturnal dyspnea, edema, crackles.
- Peripheral arterial disease: claudication relieved by rest; venous disease: edema, aching, skin changes.
- DVT and pulmonary embolism: unilateral swelling, sudden dyspnea, tachycardia.
- Breathing patterns and auscultation; pursed-lip breathing, paced breathing.
- Exercise prescription using Borg RPE, HR reserve, and MET levels; Valsalva avoidance.
Traps
Candidates use age-predicted HR max without adjusting for beta-blockers, or ignore that a patient with PAD may have rest pain suggesting critical ischemia. Orthostatic hypotension after bed rest is common; measure vitals with position change. Do not exercise a patient with unstable angina or resting dyspnea.
Worked rule
Use the Borg scale as a safety anchor when HR is unreliable: moderate intensity is about 11-13 (fairly light to somewhat hard). Stop exercise for chest pain, dizziness, severe dyspnea, or a fall in systolic BP with rising HR.