hemodynamics
MAP = DBP + ⅓ × (SBP − DBP) or MAP = (SBP + 2×DBP) ÷ 3
Normal: 70–105 mmHg
Normal: 90–140 mmHg
Normal: 60–90 mmHg
Mean arterial pressure represents the average arterial pressure throughout the cardiac cycle, weighted to reflect the longer diastolic period (approximately two-thirds of the cycle at rest). MAP is the true driving pressure for tissue perfusion — it better reflects organ blood flow than systolic BP alone. Autoregulation of most vital organs maintains flow constant across a MAP range of approximately 60–150 mmHg.
Target MAP ≥ 65 mmHg in septic shock (Surviving Sepsis Campaign guideline). Assess cerebral perfusion pressure (CPP = MAP − ICP). Guide vasopressor therapy. Determine when a patient requires vasopressors versus fluid resuscitation alone.
Normal blood pressure
→ 93 mmHg
Normal MAP — adequate for organ perfusion
Septic shock
→ 59 mmHg
MAP < 65 — inadequate organ perfusion; vasopressor initiation required
MAP < 60 mmHg risks end-organ ischemia (renal failure, myocardial ischemia, bowel ischemia, cerebral hypoperfusion). MAP > 65 is the universal resuscitation target in septic shock. In patients with chronic hypertension or known elevated ICP, higher MAP targets (70–80) may be needed. Vasopressor choice: norepinephrine is first-line for septic shock.