Hansen D, Syben R, Vargas O, Spies C, Welte M
Klinik für Anaesthesiologie und operative Intensivmedizin, Universitätsklinikum Benjamin Franklin, Freie Universität Berlin, Germany.
Anesth Analg. 1999 Mar;88(3):538-41. doi: 10.1097/00000539-199903000-00014.
Moderate hypothermia (32-33 degrees C) occurs in anesthetic practice. However, intrapulmonary gas exchange and the effect of temperature correction of blood gases on oxygen and carbon dioxide exchange have not been investigated in these patients. We investigated alveolar-arterial difference in oxygen tension (AaDO2) and arterial to end-tidal difference in carbon dioxide (Pa-ETCO2) during rewarming of eight ASA physical status I patients from hypothermia of 32 degrees C. Anesthesia was maintained with fentanyl/propofol. AaDO2 and Pa-ETCO2 were assessed by analyzing arterial blood gases and saturated water vapor pressure, uncorrected or corrected to actual body temperature. The respiratory quotient (RQ) was measured by calorimetry. After temperature correction of blood gases and water vapor pressure, the AaDO2 was significantly higher at 33 and 32 degrees C compared with 36 degrees C (56 +/- 13 and 64 +/- 14 vs 39 +/- 10 mm Hg; P < 0.05 and P < 0.01). The deterioration of pulmonary oxygen exchange was not detected if arterial blood gases and water vapor pressure were not corrected. The RQ did not change during moderate hypothermia compared with 36 +/-C. The temperature-corrected Pa-ETCO2 was not affected by hypothermia. We conclude that AaDO2 is increased during moderate hypothermia. This is only detected when water vapor pressure and arterial blood gases are corrected to actual body temperature.
We investigated intrapulmonary oxygen and carbon dioxide exchange during moderate hypothermia (32 degrees C) in eight patients. If oxygen, carbon dioxide, and water vapor pressure were corrected to actual body temperature, the alveolar-arterial oxygen tension difference was increased during hypothermia. The carbon dioxide tension difference and the respiratory quotient were unaffected by hypothermia.
麻醉实践中会出现中度低温（32 - 33摄氏度）。然而，这些患者的肺内气体交换以及血气温度校正对氧气和二氧化碳交换的影响尚未得到研究。我们调查了8例美国麻醉医师协会（ASA）身体状况I级患者从32摄氏度低温复温过程中的肺泡 - 动脉氧分压差（AaDO2）和动脉血与呼气末二氧化碳分压差（Pa - ETCO2）。麻醉维持采用芬太尼/丙泊酚。通过分析动脉血气和饱和水蒸气压（未校正或校正至实际体温）来评估AaDO2和Pa - ETCO2。通过量热法测量呼吸商（RQ）。在对血气和水蒸气压进行温度校正后，与36摄氏度相比，33摄氏度和32摄氏度时的AaDO2显著更高（56±13和64±14 vs 39±10 mmHg；P < 0.05和P < 0.01）。如果未校正动脉血气和水蒸气压，则未检测到肺氧交换恶化。与36±摄氏度相比，中度低温期间RQ未改变。温度校正后的Pa - ETCO2不受低温影响。我们得出结论，中度低温期间AaDO2增加。只有在将水蒸气压和动脉血气校正至实际体温时才能检测到这一点。
我们调查了8例患者在中度低温（32摄氏度）期间的肺内氧气和二氧化碳交换。如果将氧气、二氧化碳和水蒸气压校正至实际体温，低温期间肺泡 - 动脉氧分压差会增加。二氧化碳分压差和呼吸商不受低温影响。
