Resting energy expenditure and respiratory quotient in adolescents following spinal fusion surgery.

Abstract

Prospective, 2-factor design. The first factor was the group with 2 levels, spine surgery and control. The second factor was timing with 3 levels, baseline, 1-week follow-up, and 6-week follow-up. The purpose of this study was to assess changes in caloric requirements and the body's nutritional substrate utilization following spinal surgery in adolescents. In an effort to optimize recovery from and assure best possible outcomes after spinal surgery in adolescents, the nutritional requirements of spine surgery patients were evaluated. Indirect calorimetry was used to measure resting energy expenditure, a measure of caloric requirements, and respiratory quotient, an indication of percentages of fat, protein, and carbohydrate utilization. Twenty-three patients undergoing spinal fusion surgery were evaluated immediately before surgery, at an average of 4.8 days after surgery, and at an average 53 days follow-up. A control group of 15 patients completed the same series of 3 tests: baseline, 1-week later, and 6-weeks later. Resting energy expenditure increased significantly by 150 kcal/day (2.7 kcal/kg/day) following spinal fusion surgery in adolescents. By 6 weeks postoperation, patient's caloric requirements returned to baseline level. No changes in resting energy expenditure occurred in the control group between the 3 test periods. Anterior/posterior surgeries and single surgeries had similar kcal/kg/day requirements after surgery. Respiratory quotient decreased significantly following surgery (0.79 to 0.70), indicating a shift to fat oxidation after surgery. At 6 weeks postoperation, the respiratory quotient returned to baseline level. The control group demonstrated no change in the respiratory quotient during the 3 testing periods. Substrate utilization shifts to fat oxidation in adolescents following spinal surgery, indicating lipids would be the alimentation of choice immediately after surgery. Caloric requirements increase 9% above the baseline measurements. Anterior/posterior surgeries and single surgeries (anterior or posterior alone) have the same increase in kcal/kg/day. Because of the substrate utilization change by the body after surgery, a preponderance of these calories should initially be given as lipids. After approximately 6 weeks, both resting energy expenditure and respiratory quotient returned to preoperative levels following spinal surgery in adolescents, indicating special nutrition is not required beyond 6 weeks.