Final answer:
Supine-hypotension syndrome can occur in pregnant patients over 20 weeks gestation when the enlarged uterus compresses the vena cava, leading to a decrease in blood flow and blood pressure.
Step-by-step explanation:
Supine-hypotension syndrome can occur in the pregnant trauma patient over 20 weeks gestation when the enlarged uterus compresses the vena cava.
During pregnancy, the blood volume increases and the uterus grows larger, putting pressure on the vena cava, the major vein that returns blood from the lower body to the heart. When a pregnant woman lies flat on her back, the weight of the uterus compresses the vena cava, reducing blood flow and causing a decrease in blood pressure. This condition is known as supine-hypotension syndrome.
For example, when a pregnant woman lies on her back, the weight of the fetus, amniotic fluid, and placenta can exert pressure on the vena cava. This compression restricts blood flow and may lead to symptoms such as dizziness, lightheadedness, or fainting.