Review Question - QID 214884

A 65-year-old man with a past medical history of chronic obstructive pulmonary disease (COPD), coronary artery disease (CAD), alcoholism, chronic pancreatitis, and pancreatic adenocarcinoma is admitted to the ICU after successful open Whipple operation for attempted surgical cure of his cancer. An epidural was placed pre-operatively for post-operative pain management. Surgery was without complication and the patient received a right radial arterial line, cefazolin and metronidazole prior to incision, 3L crystalloid solution, 500cc albumin, and 2 units packed RBCs intraoperatively. He was successfully extubated and delivered to the ICU in stable condition without vasopressor requirements. Vitals at the time of ICU admission were HR 85 bpm with normal sinus rhythm on EKG, BP 132/84 mmHg, RR 16/min, SaO2 98% on room air.

3 hours after admission, the patient begins experiencing shortness of breath. HR is now 110 bpm with normal sinus rhythm on EKG, BP 110/68, RR 25/min, and SaO2 is now 83% on room air. Bedside chest X-ray shows bilateral infiltrates. Bedside echocardiogram shows no new wall motion abnormalities, LVEF 35-45% (unchanged from preoperative evaluation), and new mild right heart strain. What is the most likely pathophysiology of this patient’s clinical deterioration?