Master arterial line interpretation for nursing practice: normal A-line waveform morphology, dicrotic notch significance, dampening patterns, zeroing and leveling technique, pulse pressure variation, and clinical troubleshooting.
Systolic peak
Rapid upstroke from ventricular ejection — corresponds to systolic BP
Dicrotic notch
Brief dip following aortic valve closure — marks end of systole; absent/dampened in aortic insufficiency
Diastolic runoff
Gradual decline as blood flows to periphery — corresponds to diastolic BP
Pulse pressure
Systolic − diastolic; narrow PP = low stroke volume; wide PP = distributive shock or aortic insufficiency
Over-dampened
Low-amplitude, rounded trace — causes: air bubble, clot, kink, loose connection. Over-reads diastolic, under-reads systolic.
Under-dampened (resonant)
Exaggerated systolic spike, false-high systolic — causes: stiff tubing, incorrect fluid column. Check fast-flush square wave test.
Loss of dicrotic notch
Suggests poor peripheral vascular tone, aortic regurgitation, or over-dampening.
Pulsus paradoxus on A-line
>10 mmHg systolic drop with inspiration — suggests cardiac tamponade, severe COPD, or tension pneumothorax.
Hemodynamic Fundamentals
MAP, CVP, preload, shock states
Advanced Hemodynamics
Swan-Ganz, SVR, PAOP, SvO2
Shock & Perfusion
Shock classification and treatment
ECG Interpretation
Rhythm recognition for ICU