A novel prediction equation of resting energy expenditure for Japanese septic patients

Predictive Equation for Basal Metabolic Rate in Normal-Weight Chinese Adults

This study aimed to develop a predictive equation for basal metabolic rate (BMR) in normal-weight Chinese adults and provide a reference for establishing the national recommended dietary energy intake. A new equation for BMR was derived from a sample of 516 normal-weight Chinese adults (men = 253, women = 263), and this sample was collected from two previous studies. Furthermore, the accuracy of this new equation and eight other previous predictive equations was reviewed. The agreement and reliability were compared in terms of bias, accuracy, the intraclass correlation coefficient, and Bland-Altman plots between predictive equations. In addition, the newly developed equation was further verified using a small independent sample, which contained 41 healthy Chinese adults (men = 21, women = 20). The measured BMR (mBMR) of all participants, measured using indirect calorimetry, was 1346.2 ± 358.0 kcal/d. Thirty participants were excluded based on Cook's distance criteria (Cook's distance of ≥0.008). Previous equations developed by Henry, Schofield, Harris-Benedict (H-B), Yang, and Hong overestimated the BMR of healthy Chinese adults. The present equation displayed the smallest average bias (0.2 kcal/d) between the mBMR and predicted basal metabolic rate (pBMR). The limits of agreement of the present equation from Bland-Altman plots were -514.3 kcal/d and 513.9 kcal/d, which is the most narrow and balanced limit of agreement. Moreover, in the verification of the testing database, the pBMR of the new equation was not significantly different from the mBMR, and the accuracy was 75.6%. Compared with pre-existing equations, the present equation is more applicable to the prediction of BMR in healthy Chinese adults. However, further studies are required to verify the accuracy of this new equation.

Methodological Aspects of Indirect Calorimetry in Patients with Sepsis-Possibilities and Limitations

The aim of the review was to analyse the challenges of using indirect calorimetry in patients with sepsis, including the limitations of this method. A systematic review of the literature was carried out. The analysis concerned the methodology and presentation of research results. In most studies assessing energy expenditure, energy expenditure was expressed in kcal per day (n = 9) and as the mean and standard deviation (n = 7). Most authors provided a detailed measurement protocol, including measurement duration (n = 10) and device calibration information (n = 7). Ten papers provided information on the day of hospitalisation when the measurements were obtained, nine on patient nutrition, and twelve on the criteria for inclusion and exclusion of participants from the study. Small study group sizes and study at a single centre were among the most cited limitations. Studies assessing energy expenditure in patients with sepsis by indirect calorimetry differ in the methodology and presentation of results, and their collective analysis is difficult. A meta-analysis of the results could enable multi-site and large patient evaluation. Standardisation of protocols and presentation of all collected data would enable their meta-analysis, which would help to achieve greater knowledge about metabolism in sepsis.

Changes in carbon dioxide production and oxygen uptake evaluated using indirect calorimetry in mechanically ventilated patients with sepsis

BACKGROUND

Several clinical guidelines recommend monitoring blood lactate levels and central venous oxygen saturation for hemodynamic management of patients with sepsis. We hypothesized that carbon dioxide production (VCO₂) and oxygen extraction (VO₂) evaluated using indirect calorimetry (IC) might provide additional information to understand the dynamic metabolic changes in sepsis.

METHODS

Adult patients with sepsis who required mechanical ventilation in the intensive care unit (ICU) of our hospital between September 2019 and March 2020 were prospectively enrolled. Sepsis was diagnosed according to Sepsis-3. Continuous measurement of VCO₂ and VO₂ using IC for 2 h was conducted within 24 h after tracheal intubation, and the changes in VCO₂ and VO₂ over 2 h were calculated as the slopes by linear regression analysis. Furthermore, temporal lactate changes were evaluated. The primary outcome was 28-day survival.

RESULTS

Thirty-four patients with sepsis were enrolled, 26 of whom survived 76%. Significant differences in the slope of VCO₂ (- 1.412 vs. - 0.446) (p = 0.012) and VO₂ (- 2.098 vs. - 0.851) (p = 0.023) changes were observed between non-survivors and survivors. Of note, all eight non-survivors and 17 of the 26 survivors showed negative slopes of VCO₂ and VO₂ changes. For these patients, 17 survivors had a median lactate of - 2.4% changes per hour (%/h), whereas non-survivors had a median lactate of 2.6%/hr (p = 0.023).

CONCLUSIONS

The non-survivors in this study showed temporal decreases in both VCO₂ and VO₂ along with lactate elevation. Monitoring the temporal changes in VCO₂ and VO₂ along with blood lactate levels may be useful in predicting the prognosis of sepsis.