Hemodynamics

CRNA Study Suite · MAP · CPP · SVR · CO
All Calculators Hemodynamics
Vital Signs
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Results
MAP
--
mmHg
Pulse Pressure
--
mmHg
Shock Index
--
HR/SBP
CPP
--
mmHg
SVR
--
dynes·s/cm⁵
Cardiac Output
--
L/min
Calculation Breakdown
MAP (Mean Arterial Pressure)
MAP = DBP + ⅓ × (SBP − DBP), equivalent to (SBP + 2×DBP) / 3
--
MAP = -- mmHg    (Normal 70-105 mmHg; organ perfusion floor 60-65)
(Elisha, 2023, p. 490)
Pulse Pressure
PP = SBP − DBP
--
PP = -- mmHg    (Narrow <25% SBP = hypovolemia; wide = aortic insufficiency, thyrotoxicosis)
Shock Index
SI = HR / SBP    (Normal < 0.7; >0.9 concerning; >1.0 hemorrhagic shock)
--
SI = --
References

Elisha, S. (2023). Cardiovascular anatomy, physiology, pathophysiology, and anesthesia management. In S. Elisha, J. S. Heiner, & J. J. Nagelhout (Eds.), Nurse anesthesia (7th ed., pp. 477-515). Elsevier.

Bonanno, L. S. (2023). Neuroanatomy, neurophysiology, and neuroanesthesia. In S. Elisha, J. S. Heiner, & J. J. Nagelhout (Eds.), Nurse anesthesia (7th ed., pp. 704-741). Elsevier.

How this works

The core formulas

Mean arterial pressure is MAP = DBP + 1/3(SBP - DBP), or (SBP + 2 x DBP) / 3; minimum MAP for organ perfusion is generally 60 to 65 mmHg and normal is 70 to 105 mmHg (Elisha, 2023, p. 480). Cardiac output is HR x SV, normal 4 to 8 L/min. Cardiac index is CO / body surface area, normal 2.5 to 4.0 L/min/m2 (Elisha, 2023, p. 480).

Systemic vascular resistance

SVR = [(MAP - right atrial pressure) / CO] x 80, a gross estimate of left ventricular afterload used to guide vasopressor or vasodilator therapy (Kossick & Seale, 2023, p. 307). Normal SVR is 800 to 1200 dynes-sec/cm5 (Elisha, 2023, p. 480).

References

Elisha, S. (2023). Cardiovascular anatomy, physiology, pathophysiology, and anesthesia management. In Elisha, Heiner, & Nagelhout (Eds.), Nurse anesthesia (7th ed., pp. 477-515). Elsevier.