Question

In an individual with a heart rate of 50 beats/min, stroke volume of 80 ml, an arterial blood pressure of 140/80 mm Hg, and a right atrial pressure of 0 mm Hg, what is the total peripheral resistance?

Answer 1

The total peripheral resistance (TPR) for this individual is calculated to be 25 mm Hg × min/L using the provided cardiovascular measurements and the formula TPR = (ΔP) / (Cardiac Output).

Step-by-step explanation:

To calculate the total peripheral resistance (TPR) in an individual with specific cardiovascular measurements, we use the formula: TPR = (ΔP) / (Cardiac Output), where ΔP (delta P) is the difference between the mean arterial pressure and the right atrial pressure. In this scenario, the individual has an arterial blood pressure of 140/80 mm Hg and a right atrial pressure of 0 mm Hg.

First, we must calculate the Mean Arterial Pressure (MAP) using the equation: MAP approximately equals diastolic pressure plus one-third of the pulse pressure. Pulse pressure is the difference between the systolic and diastolic pressures. Thus, MAP = 80 + (140 - 80) / 3, giving us a value of approximately 100 mm Hg. Since the right atrial pressure is 0 mm Hg, the ΔP is simply the MAP, or 100 mm Hg.

Next, we calculate the cardiac output (CO) by multiplying the stroke volume (SV) by the heart rate (HR): CO = SV × HR. In this case, CO = 80 ml/beat × 50 beats/min, which results in 4000 ml/min (or 4 L/min).

Now we can find the TPR by dividing ΔP by CO: TPR = 100 mm Hg / 4 L/min. As the units of TPR are typically given in mm Hg × min/L, the total peripheral resistance for this individual would be 25 mm Hg × min/L.