Shaffer T H, Forman D L, Wolfson M R
Undersea Biomed Res. 1984 Sep;11(3):287-98.
Body cooling, respiratory heat loss, and the physiological effects of liquid ventilation at various temperatures were studied in 10 adult cats with applications to the deep sea diver. The animals were stabilized on mechanical gas ventilation with 100% oxygen during a control period and then mechanically ventilated for 1 h with liquid fluorocarbon. Fluorocarbon (Rimar 101) temperatures of 10 degrees C, 20 degrees C, and 30 degrees C were used to ventilate the animals while rectal and subcutaneous body temperatures were being measured. For the 3 temperature conditions, respective cooling rates of 9.0 degrees C/h, 7.8 degrees C/h, and 3.6 degrees C/h, as well as respiratory heat losses of 65,637 J X kg-1 X h-1, 33,488 J X kg-1, X h-1, 18,036 J X kg-1 X h-1 were observed while maintaining effective physiological gas exchange [mean PaO2 = 353 +/- 28 (SEM) mmHg, mean PaCO2 = 30 +/- 2 (SEM) mmHg]. Changes in cardiovascular variables were noted as mild (35 degrees C-30 degrees C) and moderate (30 degrees C-25 degrees C) levels of hypothermia were reached. Cardiac output, oxygen consumption, heart rate, and mean blood pressure were significantly correlated with rectal temperature. The data presented herein quantitate the effects of liquid ventilation on body cooling and respiratory heat loss. Furthermore, the physiological alterations associated with the observed hypothermic condition could severely limit the effectiveness of a human diver if not carefully controlled.
在10只成年猫身上研究了身体降温、呼吸散热以及不同温度下液体通气的生理效应，并将其应用于深海潜水员。在对照期，动物通过100%氧气进行机械通气稳定后，再用液体氟碳化合物进行1小时的机械通气。在测量直肠和皮下体温的同时，使用温度为10℃、20℃和30℃的氟碳化合物（Rimar 101）对动物进行通气。在3种温度条件下，观察到各自的降温速率分别为9.0℃/小时、7.8℃/小时和3.6℃/小时，呼吸散热量分别为65637焦耳·千克⁻¹·小时⁻¹、33488焦耳·千克⁻¹·小时⁻¹、18036焦耳·千克⁻¹·小时⁻¹，同时维持有效的生理气体交换[平均动脉血氧分压=353±28（标准误）毫米汞柱，平均动脉血二氧化碳分压=30±2（标准误）毫米汞柱]。当体温降至轻度低温（35℃ - 30℃）和中度低温（30℃ - 25℃）水平时，记录到心血管变量的变化。心输出量、耗氧量、心率和平均血压与直肠温度显著相关。本文所呈现的数据定量了液体通气对身体降温和呼吸散热的影响。此外，如果不仔细控制，与观察到的低温状态相关的生理改变可能会严重限制人类潜水员的效能。
