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Jorge A. Coss-Bu, MD; William J. Klish, MD, FAAP; Fernando Stein, MD, FAAP; David Walding, B.S.B.E.; Ramesh Sachdeva, MD, FAAP; Larry S. Jefferson, MD, FAAP. Department of Pediatrics, Baylor College [...], Background: Critically ill patients are characterized by a hypermetabolic state, an increased catabolic response as assessed by nitrogen balance (NB) studies, higher nutritional needs, and a decreased capacity for utilization of parenteral substrate. The aim of this study was to evaluate the effect of energy expenditure and substrate intake on NB and substrate utilization (SU) in this population. Methods: This cross-sectional study measured NB and SU in 33 critically ill children on mechanical ventilation (MV) and receiving total parenteral nutrition (TPN). Resting energy expenditure (REE) was measured by indirect calorimetry (IC) with a metabolic cart. Expected energy requirements (EER) were obtained from Talbot's tables. REE/EER index [is greater than] 1.1 defined a hypermetabolic state. Caloric intake (Tcal/kg) was calculated and NB was calculated based on nitrogen intake (NI) and total urinary nitrogen (TUN) measured by the Kjeldahl method. Tcal/NI and non-protein calories to NI (npTcal/NI) ratios were calculated. Adjusted REE, non-protein RQ (npRQ), carbohydrate (CHO), protein (PROT), and (FAT) utilization rates were calculated by the Consolazio formulas. The percentage of relative use for each substrate was calculated as (Amount oxidized-amount ingested/ amount oxidized). Lipogenesis was defined: npRQ [is greater than] 1.00. A high CHO intake was defined as [is greater than] 8 mg/kg/min. Statistical analysis was done by unpaired t-test and simple regression analysis. Results: Values are mean ± SD. N = 33 Pts. with a hypermetabolic state (n=19) had a higher fat oxidation (27 ± 70 mg/min vs -22 ± 29 mg/min, p [is less than] 0.05) and lower npRQ (0.86 ± 0.2 vs 1.21 ± 0.3, p [is less than] 0.001) compared to non-hypermetabolic pts. (n=14). Pts. with a high CHO intake (n=12) had a lower CHO oxidation (-78 ± 124 % vs 16 ± 44 %, p [is less than] 0.005) compared to pts. with normal CHO intake (n=21). Pts. in lipogenesis (n=13) had a higher CHO intake 8.5 ± 3 mg/kg/min vs 6.1 ± 3 mg/kg/ min, p [is less than] 0.05) and a lower FAT oxidation rate (-39 ± 26 mg/min vs 36 ± 60 mg/min, p [is less than] 0.0005) compared to pts. without lipogenesis (n=20). Pts. with a (+) NB (12) had a higher protein intake (2.8 ± 1 g/kg/day vs 1.7 ± 1 g/kg/day, p [is less than] 0.001) compared to pts. in (-) NB (n=21). Pts. in (-) NB had a higher PRO oxidation rate (42 ± 35 mg/min vs 13 ± 5 mg/min, p [is less than] 0.01) compared to pts. with a (+) NB. CHO intake did not correlate with rate of oxidation (r= 0.29, p= 0.09), higher PRO intake had a significant correlation with oxidation rate (r= 0.63, p [is less than] 0.0001), and FAT intake did not correlate with rate of oxidation (r= 0.29, p=0.09). Conclusions: Critically ill children on mechanical ventilation are hypermetabolic, and in negative nitrogen balance. This population preferentially uses fat for oxidation, carbohydrate is poorly utilized, with higher intake associated with lipogenesis and less oxidation of FAT. A higher PRO intake was associated with a positive NB and effective oxidation rates. A negative NB induces higher levels of PRO oxidation. Grant support: Genevieve R. McClelland Fund for Pediatric Intensive Care Research Jorge A. Coss-Bu, MD; William J. Klish, MD, FAAP; Fernando Stein, MD, FAAP; David Walding, B.S.B.E.; Ramesh Sachdeva, MD, FAAP; Larry S. Jefferson, MD, FAAP. Department of Pediatrics, Baylor College of Medicine, Houston TX.3

Looks at a study on the use of formulas modified by accepted stress factors in critically pediatric patients. Comparison of the values derived by use of the formulas with measured REE (resting energy expenditure), by indirect calorimetry; What the results show; Information on the measurements of the REE; Detailed information on the subjects used for the study; Methodology used for the study; Results of the study; Discussion on the findings of the study.