Hemodynamic Monitoring and Cardiovascular Management
Monitoring basics
Noninvasive blood pressure cuff size matters-too small a cuff falsely raises readings. ECG monitors rate and rhythm; watch for new ST changes, premature beats, and bradyarrhythmias. Invasive lines require zeroing and leveling at the phlebostatic axis. CVP estimates right atrial pressure, not intravascular volume, and is influenced by compliance and positive-pressure ventilation.
Hypotension
Classify by cause: hypovolemia (bleeding, dehydration), vasodilation (spinal or epidural sympathectomy, sepsis, anaphylaxis), cardiogenic (MI, arrhythmia, heart failure), and obstruction (tension pneumothorax, tamponade). Spinal anesthesia commonly causes bradycardia and hypotension from sympathetic blockade; treat with fluids, vasopressors, and atropine for bradycardia as ordered.
Traps
Do not assume a normal blood pressure means adequate perfusion; check mental status, urine output, and capillary refill. A damped arterial waveform underestimates systolic pressure. Local anesthetic systemic toxicity presents with neurologic symptoms then cardiovascular collapse; treatment is lipid emulsion and airway support. New chest pain or ST elevation in the PACU requires urgent ECG and provider notification.
Worked example
After spinal anesthesia, blood pressure falls from 130/80 to 82/48 with heart rate 48. The patient is awake but nauseated. Give oxygen, elevate the legs, give a fluid bolus and vasopressor per protocol, and give atropine for symptomatic bradycardia. Reassess frequently.
Rule of thumb: treat the patient, not the number-assess perfusion and the likely cause.