L24 Cardiovascular lab tests

The normal range for the heart rate is 60-100bpm.

The average cardiac output for a healthy man is 5.5 L/min.

Stroke volume is the volume of blood pumped from the ventricles (usually LV) per heart beat. It can be measured. Typically ~ [blank_start]75[blank_end] mL of blood is pumped from the left ventricle through the aorta to the vascular system with a heart beat. The normal range is [blank_start]60-120[blank_end] mL, and this is affected by preload, afterload, & contractility of the ventricles. It can be measured with [blank_start]echocardiography[blank_end]. The stroke volume = end [blank_start]diastolic[blank_end] volume - end [blank_start]systolic[blank_end] volume, i.e. the amount of blood which leaves the heart is equal to the amount of blood heart that [blank_start]entered[blank_end] the heart, minus the amount of blood [blank_start]left[blank_end] in the heart. This is measured as blood passes through heart [blank_start]valves[blank_end] during ventricular contraction, and scaled by body [blank_start]surface area[blank_end].

Cardiac output (volume per time) is not [blank_start]directly[blank_end] measured, but with doppler echocardiography we can find the SV and HR and CO is therefore [blank_start]HR x SV[blank_end].

The ejection fraction is the fraction of blood pumped from the ventricles (usually LV, LVEF) with each heart beat. Ejection fraction = [blank_start]stroke[blank_end] volume/[blank_start]end disastolic[blank_end] volume. ~ [blank_start]60[blank_end]% is normal but can appear ‘normal’ in some types of heart [blank_start]failure[blank_end]. It is measured with an echocardiogram or [blank_start]angiography[blank_end].

Blood pressure is the hydrostatic pressure exerted by circulating blood on vessel [blank_start]wall[blank_end] (usually arterial). It is measured in a large artery (usually [blank_start]brachial[blank_end]) using a [blank_start]sphygmomanometer[blank_end] (+/- a stethoscope) and expressed as systolic pressure over diastolic pressure in mmHg. Blood pressure is a function of [blank_start]CO, TPR[blank_end], and arterial compliance (AC). Normal resting blood pressure in an adult is ~ [blank_start]120/80[blank_end] mmHg and > [blank_start]140[blank_end] mmHg systolic indicates hypertension.

Mean arterial pressure, the average arterial blood pressure, is a function of cardiac output and peripheral resistance (MAP = [blank_start]CO x TPR[blank_end]), and has a median normal value of [blank_start]70[blank_end] mmHg (range [blank_start]65-110[blank_end]).

Choose the incorrect statement about CVP, central venous pressure(the hydrostatic pressure on the walls of the venae cavae near the right side of the heart.)