In a 16-year-old patient on mechanical ventilation, what is the vascular resistance of the systemic circulation if given MAP, CVP, and CO?

To determine the vascular resistance of the systemic circulation, the calculation used is based on the formula for systemic vascular resistance (SVR), which is given by the following equation:

[ SVR = \frac{(MAP - CVP) \times 80}{CO} ]

In this formula, MAP represents the mean arterial pressure, CVP is the central venous pressure, and CO stands for cardiac output. The multiplication by 80 is necessary to convert the units to dynes per second per centimeter to align with the commonly used units for vascular resistance.

The correct answer indicates a calculated SVR of 1440 dynes, which is within a typical range for systemic resistance in a patient. The value reflects an appropriate response of the circulatory system to the conditions presented, such as mechanical ventilation and the age of the patient, which may influence both vascular tone and compliance.

Understanding the components involved is critical: mean arterial pressure typically reflects the average blood pressure in the arteries during one cardiac cycle, central venous pressure indicates the pressure in the thoracic vena cava close to the right atrium, and cardiac output represents the volume of blood being pumped by the heart per minute. With these values, a healthcare provider can ascertain vascular resistance and, consequently