Watson A C, Hughes P D, Louise Harris M, Hart N, Ware R J, Wendon J, Green M, Moxham J
Kings College Hospital, London, UK.
Crit Care Med. 2001 Jul;29(7):1325-31. doi: 10.1097/00003246-200107000-00005.
In the critically ill, respiratory muscle strength usually has been assessed by measuring maximum inspiratory pressure. The maneuver is volitional, and results can be unreliable. The nonvolitional technique of bilateral anterolateral magnetic stimulation of the phrenic nerves, producing twitch transdiaphragmatic pressure, has been successful in normal subjects and ambulatory patients. In this study we used the technique in the intensive care unit and explored the measurement of twitch endotracheal tube pressure as a less invasive technique to assess diaphragmatic contractility.
Clinical study to quantify diaphragm strength in the intensive care unit.
Patients from three London teaching hospital intensive care units and high-dependency units.
Forty-one intensive care patients were recruited. Of these, 33 (20 men, 13 women) were studied.
Esophageal and gastric balloon catheters were passed through the anaesthetized nose, and an endotracheal tube occlusion device was placed in the ventilation circuit, next to the endotracheal tube. Two 43-mm magnetic coils were placed anteriorly on the patient's neck, and the phrenic nerves were stimulated magnetically.
On phrenic nerve stimulation, twitch gastric pressure, twitch esophageal pressure, twitch transdiaphragmatic pressure, and twitch endotracheal tube pressure were measured. Forty-one consecutive patients consented to take part in the study, and twitch pressure data were obtained in 33 of these. Mean transdiaphragmatic pressure was 10.7 cm H2O, mean twitch esophageal pressure was 6.7 cm H2O, and mean twitch endotracheal tube pressure was 6.7 cm H2O. The mean difference between twitch esophageal pressure and twitch endotracheal tube pressure was 0.02 cm H2O. Correlation of the means of twitch endotracheal tube pressure to twitch esophageal pressure was 0.93, and that for twitch endotracheal tube pressure to transdiaphragmatic pressure was 0.78.
Transdiaphragmatic pressure can be measured in the critically ill to give a nonvolitional assessment of diaphragm contractility, but not all patients can be studied. At present, the relationship of twitch endotracheal tube pressure to transdiaphragmatic pressure is too variable to reliably represent a less invasive measure of diaphragm strength.
在危重症患者中，呼吸肌力量通常通过测量最大吸气压力来评估。该操作是自主的，结果可能不可靠。双侧膈神经前外侧磁刺激产生膈肌抽搐跨膈压的非自主技术，已在正常受试者和非卧床患者中取得成功。在本研究中，我们在重症监护病房使用该技术，并探索测量抽搐气管插管压力作为一种侵入性较小的技术来评估膈肌收缩力。
在重症监护病房量化膈肌力量的临床研究。
来自伦敦三家教学医院重症监护病房和高依赖病房的患者。
招募了41名重症监护患者。其中33名（20名男性，13名女性）接受了研究。
将食管和胃气囊导管经麻醉的鼻腔插入，并在通气回路中气管插管旁放置气管插管阻塞装置。将两个43毫米的磁线圈放置在患者颈部前方，对膈神经进行磁刺激。
在膈神经刺激时，测量抽搐胃内压、抽搐食管内压、抽搐跨膈压和抽搐气管插管压力。41名连续患者同意参加研究，其中33名获得了抽搐压力数据。平均跨膈压为10.7 cmH₂O，平均抽搐食管内压为6.7 cmH₂O，平均抽搐气管插管压力为6.7 cmH₂O。抽搐食管内压与抽搐气管插管压力的平均差值为0.02 cmH₂O。抽搐气管插管压力均值与抽搐食管内压的相关性为0.93，抽搐气管插管压力均值与跨膈压的相关性为0.78。
可以在危重症患者中测量跨膈压以对膈肌收缩力进行非自主评估，但并非所有患者都能进行研究。目前，抽搐气管插管压力与跨膈压的关系变化太大，无法可靠地代表一种侵入性较小的膈肌力量测量方法。
