Measurements of intravacular pressure by a pulmonary aery catheter should be done:: (A) At end expiration, (B) At peak of inspiration, (C) During mid inspiration, (D) During mid expiration
Answer is A. Answer is A (At end expiration): The changes in intrathoracic pressure that occur during different phases of respiration influence measurement of intravascular pressure. These changes are minimal at end expiration which therefore is the best phase for measurement of intravascular pressure.