The respiratory quotient has little value in evaluating the state of feeding in burn patients

The respiratory quotient (RQ) is frequently used to predict over or under feeding in burn patients. The purpose of our study was to evaluate the usefulness of RQ obtained from indirect calorimetry to assess feeding adequacy in pediatric burn Intensive Care Unit patients. We evaluated pediatric patients who received enteral nutrition by continuous duodenal tube feeding at a calculated goal rate in the burn intensive care unit from January 2003 to March 2006. RQ lower than 0.85 indicated underfeeding and RQ greater than 1.0 indicated overfeeding. Actual energy intake was recorded and compared with the energy intake divided by measured resting energy expenditure. Underfeeding was defined as a nutritional regimen providing <90% of caloric requirement; appropriate feeding was provision of within +/-10% of caloric requirements and overfeeding was provision of >110% of caloric requirements. On the basis of regression analysis, there was no relationship between energy intake divided by measured resting energy expenditure and RQ (R2 = 0.0059). There was also no relationship between measured RQ and the degree of feeding (N = 222). RQ <0.85 as an indicator of underfeeding had a low sensitivity of 40% and specificity of 77%. RQ >1.0 as an indicator of overfeeding had a poor sensitivity of 23% and a specificity of 85%. The RQ, used in isolation, is a poor method to assess over or underfeeding. Future prospective studies are needed to determine the optimal methodology for the assessment of nutritional needs in children with burn injury.