Chapter 18: Nutritional Support of the Pediatric Surgical ICU Patient

INTRODUCTION

Appropriate nutritional support is essential to the care of children undergoing surgery, not only to assure appropriate wound healing and convalescence, but also to ensure normal future growth. The limited lean body mass of neonates and children makes them particularly sensitive to injury-induced catabolism and its associated morbidity and mortality. Despite this catabolic response, a carefully designed nutritional support regimen can spur anabolism. Without question, the advancement of nutritional therapy, including parenteral nutrition, has played a key role in improved survival of a number of neonatal and childhood surgical conditions.

Pediatric surgical intensive care unit (ICU) patients present unique challenges: They are prone to inadequate enteral feeding due to anorexia, enteral nutrition (EN) intolerance, and perioperative ileus. Among other diagnoses, managing critically ill intestinal failure (IF) patients may be particularly complex. Furthermore, pediatric surgical patients may respond differently to the stress of surgery than do adults.

The postoperative increase in energy requirement in neonates is remarkably transient. This adds a degree of complexity in establishing the appropriate nutritional regimen for these patients. While many of the basic principles of critical care nutrition apply to the surgical patient, specific diagnoses and operations warrant special consideration.

PERIOPERATIVE NUTRITION: AN OVERVIEW

As with any patient, the essential questions in providing nutrition to pediatric surgical patients are (1) when to provide nutritional support, (2) how much to give, (3) what route to employ, and finally (4) what formulation to give.

When to Support: Preoperative Nutrition

For malnourished adults undergoing planned operations, a period of 2 to 3 weeks of preoperative EN has been shown to reduce operative complications, including overall hospital length of stay, surgical site infections, anastomotic leak, and renal and hepatic failure.¹ The application of these findings in young children is unclear. The use of perioperative parenteral nutrition (PN) is controversial. A meta-analysis of preoperative PN for mild-to-moderately malnourished patients showed little benefit and potential increase in complications.² Patients with severe malnutrition may benefit from 7 to 15 days of preoperative PN and 3 days of postoperative PN, though infection risk is higher in this group.³ These recommendations may not apply to neonates since they have exceptionally limited nutritional stores.

There is a sizeable body of literature showing the ill effects of preoperative starvation on the metabolic state after surgery. In adult patients, preoperative starvation has been associated with worsening of insulin resistance, which is typically seen after surgery; this is an independent risk factor for an increase in length of stay.⁴ Multiple adult studies have shown the reversal of this insulin resistance by providing a carbohydrate load (either orally or intravenously) about 2 hours prior to surgery.^4-7 This concept has not been tested in children.

Postoperative Nutrition

In critically ill adults, early ...