Kram H B, Appel P L, Fink S, Shoemaker W C
Department of Surgery, King-Drew Medical Center, Los Angeles, CA.
Resuscitation. 1988 Oct;16(4):263-9. doi: 10.1016/0300-9572(88)90113-x.
In order to evaluate potential applications of non-invasive fiberoptic conjunctival carbon dioxide (Pcj,CO2) and polarographic oxygen (Pcj,O2) sensors, we studied the effects of graded hyper- and hypoventilation on Pcj,CO2 and Pcj,O2 values in dogs. Pcj,CO2 values correlated well with Pa,CO2 (r = 0.95, n = 114); the mean Pcj,CO2--Pa,CO2 gradient was 4 +/- 3 (S.D.) Torr. Both hyper- and hypoventilation resulted in decreased Pcj,O2 values, whereas decreased Pa,O2 was observed only during hypoventilation; thus, the Pcj,O2/Pa,O2 index decreased during hyperventilation but was maintained during hypoventilation. Because both cerebral and conjunctival capillary beds vasoconstrict during hyperventilation, this methodology may assist in the non-invasive monitoring of cerebral oxygenation during cerebral resuscitation and surgery. Non-invasive Pcj,CO2 monitoring, which reflects Pa,CO2 during changes in ventilation, may be used to simplify ventilator management and weaning, as well as guide appropriate timing of arterial blood gas analysis in hemodynamically stable patients.
为了评估无创光纤结膜二氧化碳（Pcj,CO2）和极谱氧（Pcj,O2）传感器的潜在应用，我们研究了分级过度通气和通气不足对犬Pcj,CO2和Pcj,O2值的影响。Pcj,CO2值与动脉血二氧化碳分压（Pa,CO2）密切相关（r = 0.95，n = 114）；Pcj,CO2与Pa,CO2的平均差值为4±3（标准差）托。过度通气和通气不足均导致Pcj,O2值降低，而仅在通气不足时观察到动脉血氧分压（Pa,O2）降低；因此，过度通气时Pcj,O2/Pa,O2指数降低，而通气不足时该指数保持不变。由于过度通气时脑和结膜毛细血管床均会收缩，该方法可能有助于在脑复苏和手术期间对脑氧合进行无创监测。无创Pcj,CO2监测可反映通气变化时的Pa,CO2，可用于简化机械通气管理和撤机，以及指导血流动力学稳定患者进行动脉血气分析的合适时机。
