Cardiac-pulmonary edema and low pulmonary capillary wedge pressure

We describe a patient who presented with acute massive pulmonary edema, clinically and on chest roentgenogram. Two hours later the patient became hypotensive and was found to have a low pulmonary capillary wedge pressure (PCWP). The blood pressure returned to normal after administration of fluids. Acute pulmonary edema develops if PCWP rises higher than 25 to 30 mm Hg. In our patient, the elevated PCWP fell to low normal within two hours, when chest roentgenogram and clinical examination still suggested severe pulmonary edema. A phase lag existed between lowering of the pulmonary capillary wedge pressure and clearing of fluid from the alveolar and interstitial spaces in the lungs. At least three different pathogenetic mechanisms in patients with coronary artery disease can produce this phase lag. Transient global ischemia of the left ventricle was thought to be the responsible mechanism in our patient.