Fluid exchange between extracellular and intracellular spaces

Total body water in a normal 70-kg man is about 40 liters, of which 25 liters are in cells and 15 liters are in the extracellular volume. Plasma (3 liters) and the interstitial fluid (12 liters) comprise the extracellular volume. These fluids have identical crystalloid osmotic pressures and when isotonic saline is infused into the vascular system of normal patients, only about a fifth to a quarter of the volume remains in the plasma. If parenchymal cells are hypoxic and cannot maintain their normal ionic distributions, then extracellular fluid enters the cells. Potential fluid spaces, such as the subcutaneous and peritoneal spaces, can hold enormous volumes of extracellular fluid. Overexpansion of plasma volume disrupts epithelial barriers in the gastrointestinal tract and lungs, causing fluid loss into the intestine and the formation of alveolar edema in the lungs. These events often occur during attempts to increase blood flow and oxygen delivery in patients with multiorgan failure and can promote a vicious cycle. Thus the goal is to maintain an adequate cardiac output to provide optimal O 2 delivery in critically ill patients without promoting excessive tissue edema (T3I\oL§L§.L 1997).

Sleep Apnea

Sleep Apnea

Have You Been Told Over And Over Again That You Snore A Lot, But You Choose To Ignore It? Have you been experiencing lack of sleep at night and find yourself waking up in the wee hours of the morning to find yourself gasping for air?

Get My Free Ebook


Post a comment