Brandi L S, Grana M, Mazzanti T, Giunta F, Natali A, Ferrannini E
Department of Anesthesiology and Intensive Care, University of Pisa, Italy.
Crit Care Med. 1992 Sep;20(9):1273-83. doi: 10.1097/00003246-199209000-00014.
To compare a method of measuring energy expenditure and gas exchange using the Fick principle with the standard indirect calorimetry technique.
Prospective study of a consecutive sample of postoperative patients. Oxygen consumption (VO2), CO2 production (VCO2), respiratory quotient, and energy expenditure were derived from measurements of variables, including oxygen content and cardiac output. Energy expenditure and gas exchange were measured simultaneously by continuous indirect calorimetry over a 60-min period.
Surgical ICU in a university hospital.
Twenty-six consecutive patients (45 to 80 yrs) who underwent sustained surgical trauma. Excluded from the study entry were patients with time-related fluctuations of hemodynamic variables, poor cooperation, patients who required supplemental oxygen, or mechanical ventilation.
None.
While the measurements of VO2 and VCO2 by calorimetry and thermodilution were significantly correlated with one another (for VO2, r2 = .93, p less than .001; for VCO2, r2 = .26, p less than .01), VO2 and VCO2 values by indirect calorimetry were consistently greater than VO2 and VCO2 values by the Fick method (p less than .01). The respiratory quotient calorimetric measurements ranged between 0.69 and 0.99, whereas the corresponding thermodilution measurements spread to impossible values, from 0.24 to 1.30 (0.821 +/- 0.07 vs. 0.740 +/- 0.24, p less than .05). There was an insignificant relationship (r2 = .06, p = .21) between the values of respiratory quotient by the two methods. A strong, positive correlation between energy expenditure measured by indirect calorimetry and energy expenditure measured by the Fick method was observed (r2 = .92, p less than .001). The limit of agreement between the two methods was -0.24 +/- 73 kcal/day/m2 (-1.00 +/- 305 kJ/day/m2).
In postoperative patients, while VO2 and energy expenditure measurements by thermodilution are easy to perform and accurate for clinical purposes, VCO2, and respiratory quotient measurements are too imprecise and inaccurate to serve any useful function. Therefore, in those clinical situations in which an evaluation of respiratory quotient and substrate utilization may be useful for purposes of metabolic care of the surgical patient, precise measurements of gas exchange with indirect calorimetry are mandatory.
比较一种利用菲克原理测量能量消耗和气体交换的方法与标准间接量热法技术。
对术后患者连续样本进行前瞻性研究。通过测量包括氧含量和心输出量等变量得出氧耗量（VO₂）、二氧化碳生成量（VCO₂）、呼吸商和能量消耗。在60分钟内通过连续间接量热法同时测量能量消耗和气体交换。
大学医院的外科重症监护病房。
26例连续接受持续性外科创伤的患者（45至80岁）。血流动力学变量存在时间相关波动、合作不佳、需要补充氧气或机械通气的患者被排除在研究对象之外。
无。
虽然量热法和热稀释法测量的VO₂和VCO₂彼此显著相关（对于VO₂，r² = 0.93，p < 0.001；对于VCO₂，r² = 0.26，p < 0.01），但间接量热法测得的VO₂和VCO₂值始终大于菲克法测得的VO₂和VCO₂值（p < 0.01）。量热法测量的呼吸商范围在0.69至0.99之间，而相应的热稀释法测量值则分散到不可能的值，从0.24至1.30（0.821 ± 0.07对0.740 ± 0.24，p < 0.05）。两种方法测得的呼吸商值之间存在不显著的关系（r² = 0.06，p = 0.21）。观察到间接量热法测量的能量消耗与菲克法测量 的能量消耗之间存在强烈的正相关（r² = 0.92，p < 0.001）。两种方法之间的一致性界限为 -0.24 ± 73千卡/天/平方米（-1.00 ± 305千焦/天/平方米）。
在术后患者中，虽然热稀释法测量VO₂和能量消耗易于进行且对临床目的而言准确，但VCO₂和呼吸商测量过于不精确和不准确，无法发挥任何有用功能。因此，在那些对手术患者进行代谢护理时评估呼吸商和底物利用可能有用的临床情况下，必须采用间接量热法精确测量气体交换。
