Q: During institution of prone position, care should be taken to support the abdomen while patient stays prone? 

 A) True 
B) False


Answer: B

Actually, on application of prone position in ARDS,  patient's abdomen should be left unsupported to decrease effect of intra-abdominal pressure. Only thorax should be supported. Unsupported abdomen and supported thorax (making heart dependent) results in its benefit. More homogeneous Ppl gradient in ventrodorsal and cephalocaudal planes improves the ventilation distribution, resulting in more homogeneous perfusion. And, smaller volume of dependent lung decreases the shunting.