Answer :
Final answer:
Positive pressure ventilation leads to vasoconstriction of arterioles 2. decreasing blood flow to the kidneys, thereby reducing glomerular filtration rate and urine formation.
Explanation:
Positive pressure ventilation can affect kidney function by initiating vasoconstriction of the arterioles, which leads to a decrease in blood flow to the kidneys. When these arterioles constrict, there is a reduction in the glomerular blood flow, and consequently, the rate of filtration and urine formation may decrease. This is a form of the body's response mediated by the sympathetic nervous system under stress conditions, where blood is redirected to more vital organs, and the renal blood flow is reduced. Additionally, angiotensin II, a potent vasoconstrictor, is produced in response to reduced kidney blood flow and leads to the release of aldosterone, which promotes fluid retention and helps restore blood pressure and blood volume. For these reasons, positive pressure ventilation generally decreases blood flow to the kidneys.
