Critical Care Medicine-Renal, Electrolyte and Acid Base Disorders>>>>>Oliguria and Polyuria
Question 2#

A 45-year-old man is admitted for urgent laparoscopic cholecystectomy for severe cholecystitis. His medical history was significant for chronic kidney disease and moderate to severe pulmonary hypertension which is being treated with continuous epoprostenol infusion at home. Intraoperative transesophageal echocardiogram showed depressed right ventricular systolic function. Intraoperative course was complicated by blood loss, requiring 2 units of packed red blood cells and 500 mL of lactated ringer. Postoperatively, he remained sedated and intubated and transferred to the intensive care unit (ICU) for close monitoring. His home-dose IV epoprostenol was continued intraoperatively and in the ICU. During his first postoperative day, he made minimal urine. Oxygen saturation is 100%, and estimated pulmonary artery pressure is at baseline, however, central venous pressure has increased. 

Which of the following is the next BEST step in management?

A. Repeat transesophageal echocardiogram to reassess the right ventricular function
B. Obtain a nephrology consult to start continuous renal replacement therapy
C. Switch intravenous epoprostenol to inhaled epoprostenol
D. Administer a bolus of albumin in to improve the urine output

Correct Answer is B

Comment:

Correct Answer: B

Acute right ventricular failure can occur in patients with moderate to severe pulmonary hypertension. Compared to the left ventricle, the right ventricle is more sensitive to increases in afterload. As a result, in this patient, who already has right ventricular dysfunction, efforts must be made to minimize right ventricular afterload. Factors such as hypoxemia, hypercapnia, hypothermia, high airway pressure, positive end-expiratory pressure, and acidosis can increase pulmonary vascular resistance.

Additional fluid challenge could be detrimental in this patient with depressed right ventricular function. It may increase the risk of right heart failure, especially since the increasing central venous pressure is an indicator of right heart volume overload (nswer D). Renal failure and associated metabolic acidosis will also be poorly tolerated by this patient, since acidosis will worsen pulmonary vascular resistance and right ventricular afterload. Hence, early intervention with renal replacement therapy to avoid renal acidosis is most beneficial. Moreover, renal replacement therapy will also help correct volume status, especially since he is anuric (Answer B). 

The patient’s pulmonary artery pressure and pulmonary vascular resistance remained stable which indicates that the intravenous epoprostenol has been effective. Inhaled and intravenous administration of epoprostenol is similarly effective and therefore no indication to change (Answer C). While transesophageal echocardiogram allows direct assessment of ventricular function, it requires equipment and the availability of an expert who can acquire and interpret the images. As a result, in the patient with impending sign of right ventricular failure, transesophageal echocardiogram should not be a priority (Answer A).

References:

  1. Gordon C, Collard CD, Pan W. Intraoperative management of pulmonary hypertension and associated right heart failure. Curr Opin Anaesthesiol. 2010;23(1):49-56. doi:10.1097/ACO.0b013e3283346c51.
  2. Subramaniam K, Yared JP. Management of pulmonary hypertension in the operating room. Semin Cardiothorac Vasc Anesth. 2007;11(2):119-136
  3. Cioccari L, Baur HR, Berger D, et al. Hemodynamic assessment of critically ill patients using a miniaturized transesophageal echocardiography probe. Crit Care. 2013;17(3):R121. doi:10.1186/cc12793.