Nutrition support for patients after cardiopulmonary bypass: required modifications of the TPN solution.

OBJECTIVE

This study was designed to identify the unique metabolic characteristics of patients undergoing cardiopulmonary bypass (CPB) surgery who require postoperative parenteral nutrition.

SUMMARY BACKGROUND DATA

Patients undergoing CPB surgery occasionally develop postoperative complications that result in the need for nutrition support. Although enteral nutrition is generally the preferred feeding route, symptomatic hyperlipasemia has been described in critically ill CPB patients receiving enteral nutrition proximal to the ligament of Treitz. In such instances, enteral feeding must be temporarily discontinued or severely curtailed, thereby necessitating the initiation of parenteral nutrition for full or partial support.

METHODS

The period from 1988 through 1993 during which time 4091 CPB procedures were performed was reviewed. Data were retrospectively collected on 208 (5%) of the patients who underwent CPB who developed postoperative complications that necessitated the initiation of parenteral nutrition (PN) support. A random sample of 79 patients who underwent CPB who did not require PN were selected as controls.

RESULTS

Patients requiring PN after CPB were significantly older and had a higher prevalence of diabetes and metabolic complications, specifically volume overload, hyponatremia, metabolic alkalosis, uremia, and hyperglycemia, than those patients who did not require PN after CPB. In addition, patients requiring PN after CPB were significantly more hypotensive and required more vasopressive drugs during the first 24 to 48 hours after surgery than control patients.

CONCLUSIONS

In patients with postoperative complications after CPB, PN is often necessary to correct the metabolic characteristics of overhydration, hyponatremia, uremia, hyperglycemia, and alkalosis.