School of Medicine, University of Missouri, Columbia, MO, USA.
J Intensive Care Med. 2010 May-Jun;25(3):168-71. doi: 10.1177/0885066609358954.
Flexible fiberoptic bronchoscopy may be performed in infants and children for various diagnostic and therapeutic purposes. In infants and children, general anesthesia may be used to facilitate the procedure. When general anesthesia is used, a laryngeal mask may be used to control the airway. However, as the passage of the bronchoscope decreases the cross-sectional airway inside the laryngeal mask airway (LMA) for gas exchange, increases in respiratory resistance may occur. We present our experience with the use of a helium-oxygen mixture to facilitate bronchoscopy through an LMA during general anesthesia in infants and children.
We retrospectively reviewed changes in tidal volume, respiratory rate, and transcutaneous carbon dioxide (TC-CO(2)) during 3 phases of general anesthetic care. Phase 1 was pressure support breathing of an air-oxygen mixture through an LMA during sevoflurane anesthesia prior to the start of bronchoscopy, phase 2 was with the bronchoscope inserted through the LMA during pressure support ventilation of sevoflurane in an air-oxygen mixture, and phase 3 was with the bronchoscope inserted through the LMA during pressure support breathing of sevoflurane in a helium-oxygen mixture.
The study cohort included 6 patients, ranging in age from 14 to 49 months. There was a statistically significant increase in respiratory rate, increase in TC-CO(2), and decrease in tidal volume with the insertion of the bronchoscope through the LMA when compared to baseline values (phase 2 vs phase 1). These values returned to values that were comparable to the baseline values when a helium-oxygen mixture was administered (phase 1 vs phase 3).
A helium-oxygen mixture decreases resistance to gas flow during bronchoscopy through an LMA in infants and children receiving general anesthesia with sevoflurane and pressure support ventilation.
纤维支气管镜检查可在婴儿和儿童中用于各种诊断和治疗目的。在婴儿和儿童中，全身麻醉可用于促进该过程。当全身麻醉时，喉罩可用于控制气道。然而，由于支气管镜的通过使用于气体交换的喉罩气道（LMA）内的气道横截面积减小，呼吸阻力可能增加。我们介绍了在婴儿和儿童全身麻醉期间使用氦-氧混合物通过 LMA 促进支气管镜检查的经验。
我们回顾性地审查了全身麻醉护理 3 个阶段的潮气量、呼吸频率和经皮二氧化碳（TC-CO2）的变化。第 1 阶段是在支气管镜检查开始之前，通过 LMA 在七氟醚麻醉下进行压力支持通气，吸入空气-氧气混合物；第 2 阶段是在压力支持通气的空气-氧气混合物中，通过 LMA 插入支气管镜；第 3 阶段是在压力支持通气的氦-氧气混合物中，通过 LMA 插入支气管镜。
该研究队列包括 6 例年龄在 14 至 49 个月的患者。与基线值（第 2 阶段与第 1 阶段）相比，通过 LMA 插入支气管镜时呼吸频率增加、TC-CO2 增加、潮气量减少。当给予氦-氧混合物时，这些值恢复到与基线值可比的值（第 1 阶段与第 3 阶段）。
在接受七氟醚和压力支持通气全身麻醉的婴儿和儿童中，氦-氧混合物可降低通过 LMA 进行支气管镜检查时的气流阻力。
