Wilding Laura A, Hampel Joe A, Khoury Basma M, Kang Stacey, Machado-Aranda David, Raghavendran Krishnan, Nemzek Jean A
Research Animal Resources, University of Minnesota, Minneapolis, Minnesota;, Email:
MPI Research, Mattawan, Michigan.
J Am Assoc Lab Anim Sci. 2017 Mar 1;56(2):148-154.
At research institutions, isoflurane delivered by precision vaporizer to a face mask is the standard for rodent surgery and for procedures with durations that exceed a few minutes. Pure oxygen is often used as the carrier gas for isoflurane anesthesia, despite documented complications from long-term 100% oxygen use in humans and known occupational safety risks. We therefore examined the effect of anesthetic delivery gas on physiologic variables in mice and rats. Rodents were anesthetized for 60 min with isoflurane delivered in either 21% or 100% oxygen by means of a nose cone. We noted no difference between carrier gasses in physiologic variables in mice, including body temperature, respiratory rate, mean arterial pressure, surgical recovery time, pH, or PaCO2. However, blood gas analysis revealed evidence of a ventilation-perfusion mismatch in the 100% oxygen group. Pressure-volume hysteresis and histomorphometric analyses confirmed the presence of increased atelectasis in mice that received 100% oxygen. Unlike mice, rats that received isoflurane in 100% oxygen had acute respiratory acidosis and elevated mean arterial pressure, but atelectasis was similar between carrier gasses. Our data suggest that both 100% and 21% oxygen are acceptable for the delivery of isoflurane to mice. However, mice anesthetized for studies focused on lung physiology or architecture would benefit from the delivery of isoflurane in 21% oxygen to reduce absorption atelectasis and the potential associated downstream inflammatory effects. For rats, delivery of isoflurane in 21% and 100% oxygen both caused perturbations in physiologic variables, and choosing a carrier gas is not straightforward.
在研究机构中，通过精密蒸发器输送到面罩的异氟烷是啮齿动物手术以及持续时间超过几分钟的手术的标准麻醉剂。尽管有文献记载人类长期使用纯氧会出现并发症以及已知的职业安全风险，但纯氧常被用作异氟烷麻醉的载气。因此，我们研究了麻醉载气对小鼠和大鼠生理变量的影响。通过鼻锥以21%或100%的氧气输送异氟烷，将啮齿动物麻醉60分钟。我们发现，在小鼠的生理变量方面，包括体温、呼吸频率、平均动脉压、手术恢复时间、pH值或动脉血二氧化碳分压，两种载气之间没有差异。然而，血气分析显示100%氧气组存在通气-灌注不匹配的证据。压力-容积滞后和组织形态计量学分析证实，接受100%氧气的小鼠肺不张增加。与小鼠不同，接受100%氧气中异氟烷麻醉的大鼠出现急性呼吸性酸中毒且平均动脉压升高，但两种载气导致的肺不张相似。我们的数据表明，21%和100%的氧气都可用于向小鼠输送异氟烷。然而，针对肺部生理学或结构的研究中，用21%氧气输送异氟烷麻醉小鼠，将有助于减少吸收性肺不张及潜在的相关下游炎症效应。对于大鼠，用21%和100%氧气输送异氟烷都会引起生理变量的紊乱，选择载气并非易事。
