Mayfield S R
Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas.
Am J Clin Nutr. 1991 Jul;54(1):30-4. doi: 10.1093/ajcn/54.1.30.
Testing of a proprietary indirect calorimeter (MGM, Jr.) was performed by using nitrogen displacement and added carbon dioxide to simulate oxygen consumption (VO2), carbon dioxide production (VCO2), and the respiratory quotient (RQ; VCO2/VO2). Errors in measured VO2, VCO2, and RQ were less than or equal to 2.5% when VO2 and VCO2 were 4-43 mL/min and flow rate was 100-2000 mL/min. The relative error in predicted VO2 was increased as the inspired oxygen concentration (FiO2) was raised but the error was less than 4% when the value of FiO2 minus expired oxygen concentration (FeO2) was greater than or equal to 0.015 and the FiO2 was less than or equal to 0.6. Sixteen studies were performed on seven very-low-birth-weight (VLBW), mechanically ventilated infants aged less than or equal to 11 d. VO2 was 8.37 +/- 1.81 mL.kg-1.min-1, VCO2 was 8.15 +/- 2.03 mL.kg-1.min-1, and RQ was 0.969 +/- 0.061 (means +/- SD). The MGM, Jr. is accurate for studies of low-birth-weight infants on mechanical ventilators when VO2 and VCO2 are greater than or equal to 4 mL/min, flow rate is less than or equal to 3000 mL/min, and FiO2 is less than or equal to 0.6. Clinical testing resulted in values similar to previously published data but the variability was higher.
通过使用氮气置换并添加二氧化碳来模拟氧耗量（VO2）、二氧化碳产生量（VCO2）和呼吸商（RQ；VCO2/VO2），对一种专利间接热量计（MGM，Jr.）进行了测试。当VO2和VCO2为4 - 43 mL/分钟且流速为100 - 2000 mL/分钟时，测量的VO2、VCO2和RQ的误差小于或等于2.5%。随着吸入氧浓度（FiO2）升高，预测VO2的相对误差增加，但当FiO2减去呼出氧浓度（FeO2）的值大于或等于0.015且FiO2小于或等于0.6时，误差小于4%。对7名出生体重极低（VLBW）、机械通气且年龄小于或等于11天的婴儿进行了16项研究。VO2为8.37±1.81 mL·kg-1·min-1，VCO2为8.15±2.03 mL·kg-1·min-1，RQ为0.969±0.061（均值±标准差）。当VO2和VCO2大于或等于4 mL/分钟、流速小于或等于3000 mL/分钟且FiO2小于或等于0.6时，MGM，Jr.对于机械通气的低出生体重婴儿的研究是准确的。临床测试得到的值与先前发表的数据相似，但变异性更高。
