Consistency study of indirect calorimetry and HB equation for measuring energy expenditure of patients with multiple injury receiving mechanical ventilation / 中华危重病急救医学

ABSTRACT

Objective To evaluate the difference and correlation of 24-hour energy expenditure in patients with multiple trauma receiving mechanical ventilation predicted by indirect calorimetry (IC) and HB formula. Methods 140 patients with multiple trauma receiving mechanical ventilation admitted to intensive care unit (ICU) of the General Hospital of Ningxia Medical University from December 1st, 2016 to August 31st, 2017 were enrolled. The 24-hour energy expenditure of patients was repeatedly measured at 1, 3, 5, and 7 days after ICU admission by IC method, and the 24-hour energy expenditure measured by IC method was used as the "gold standard" to calculate the 24-hour kilogram body weight energy expenditure. The 24-hour energy expenditure value measured by IC method was compared with the 24-hour energy expenditure predicted value calculated by HB formula method, the consistency of the two measurement methods was detected by Bland-Altman method, and the correlation between the two measurement methods was analyzed by Pearson method and the linear equation was fitted. Results The 24-hour energy expenditure of patients at 1, 3, 5 and 7 days after ICU was repeatedly measured by IC method for 501 times, and there was no significant difference in 24-hour energy expenditure (kJ/d 8 163.1±1 599.4, 8 221.1±1 694.7, 8 445.8±1 756.4, 8 707.0±1 820.7, respectively, F = 2.451, P = 0.063) and 24-hour kilogram body weight energy expenditure (kJ·kg-1·d-1 120.5±18.9, 121.4±19.7, 122.7±19.3, 121.4±19.3, respectively, F = 0.252, P = 0.860) at each time point, indicating that the first week of multi-injury patients had no significant changes in energy metabolism. The consistency between the 24-hour energy expenditure measured by IC method on the first day [(8 163.1±1 599.4) kJ/d] and that predicted by HB formula method [(6 568.8±782.0) kJ/d] was analyzed. The results showed that there was significant bias between the two methods, with an average bias of -(1 591.8±121.4) kJ/d, but the correlation analysis showed that there was a linear correlation between them (r = 0.439, P = 0.000), using one-way regression, the fitted linear equation was Y = 2 270.5+0.897X (X was 24-hour energy expenditure predicted by the HB formula). Conclusions The energy metabolism of patients with multiple trauma receiving mechanical ventilation is not obvious within 1 week. The HB formula method underestimates the 24-hour energy expenditure of patients. The prediction formula can be used to correct the HB formula and further to improve the accuracy of predicting the 24-hour energy consumption of patients.