Indirect Calorimetry:the Effect Of Evaluation For Critically Ill Patients In The Nutritional Status

Object: To compare the differences of resting energy expenditure(REE) between measured by indirect calorimetry and derived from Harris-Benedict formula in critically ill patients. To explore the difference of bias between REE measured by indirect calorimetry and derived from Harris-Benedict formula in critically ill patients.To analyze the correlation of REE with serum precursor protein and transferring.We aim to confirm the differences of bias in different types of critically ill patients.To assess the nutritional status evaluated by indirect calorimetry, to provide evidence for nutrition support therapy.To evaluate the clinical significance of indirect calorimetry in the monitoring and treatment of critically ill patients.Method: The subjects in our prospective study were 90 critically ill cases on mechanical ventilation. All patients come from intensive critical unit of First Affiliated Hospital of Fujian Medical University during April 2014 to March 2015. According to the diagnostic criteria of systemic inflammatory response syndrome(SIRS) and sepsis, the 90 patients were divided into sepsis group(30 cases), non-septic SIRS group(30 cases), non-SIRS group(30 cases).Their REE was estimated by the Harris-Benedict formula, after multiplied by the appropriate stress factor. we acquired the predicted REE. The REE was monitored by indirect calorimetry. Patient data that might influence REE, such as serum precursor protein and transferrin,were assessed, REE, measured by indirect calorimetry, was compared to estimated REE by the Harris-Benedict throughone-way analysis of variance. The bias between the individual groups analyzed. Spearman correlation coefficients were conducted to determine the relations between measured REE. We compared the REE detected by indirect calorimetry, serum precursor protein and transferring among the 3 groups, to evaluate the role of indirect calorimetry detecting REE of sepsis patient for assessing their nutritional status.Result: A significant differences was found between measured REE(non-SIRS group 1314.00±137.09 kcal/d)(non-septic SIRS group 1574.26±148.89 kcal/d)(septic group 1781.53±142.30 kcal/d) and REE derived from the Harris-Benedict equation(non-SIRS group 1208.60±123.13 kcal/d)(non-septic SIRS group 1356.60±139.00 kcal/d)(septic group 1534.33±221.82kcal/d)(P <0.05). REE,in sepsis group via indirect calorimetry monitoring, was significantly higher than that in non-sepsis SIRS group and non-SIRS group(P < 0.05).Among the 3 groups, the mean bias were(105.4±60.4、217.7±89.7、247.2±117.9), the bias of sepsis group was significant larger than of the other 2 groups(P <0.05). The serum precursor protein and transferring were highly correlated in critically ill patients.(r=0.967),(P <0.01).REE detected by indirect calorimetry was negatively correlated with serum precursor protein(r=-0.615),(P<0.01)and transferrin(r =-0.658),(P<0.01).Conclusion: Indirect calorimetry is more reliable than correcting Harris-Benedict formula in evaluating the nutritional status of critically ill patients. Sepsis group had higher.There is bias in REE between detecting by indirect calorimetry and deriving from Harris-Benedict formula.Sepsis patients have higher the bias between indirect calorimetry and Harris-Benedict formula of sepsis group is larger than of the non-septic SIRS group and the non-SIRS group. The serum precursor protein was highly correlated with transferrin in critically ill patients.REE was negatively correlated with serum precursor protein and transferrin. Serum precursor protein and transferrin had limitation on the nutritional status evaluating in critically ill patients.REE is an excellentindicator in assessing the nutritional status of critically ill patients. Indirect calorimetryappears to be a useful way of determining nutritional status. It can help to accurately determine the condition and provide evidence for clinical decision making.