Asai T, Murao K, Shingu K
Department of Anaesthesiology, Kansai Medical University, Osaka, Japan.
Br J Anaesth. 2000 Aug;85(2):256-61. doi: 10.1093/bja/85.2.256.
We studied 70 patients to see if cricoid pressure applied after insertion of the laryngeal mask altered the success rate of tracheal intubation through the mask. After induction of anaesthesia and neuromuscular blockade, patients were randomly allocated to have either cricoid pressure (Group C) or sham pressure (Group S). The view of the glottis through the laryngeal mask was assessed before and after the test pressure, and tracheal intubation through the mask was attempted using a fibreoptic bronchoscope. The test pressure did not alter the view of the glottis in any patient in group S, whereas it narrowed the glottic aperture in 16 out of 35 patients in group C. The fibrescope was inserted into the trachea in all patients in group S and in 25 patients in group C. The success rate of tracheal intubation in group S (31 patients) was significantly higher than in group C (21 patients, P << 0.001; 95% CI for difference: 9-48%). The time for insertion of the fibrescope in group S (median (95% CI): 12 (11-12) s) was significantly faster than in group C (16 (14-17) s, P << 0.001; 95% CI for difference: 3-6 s), and the time for tracheal intubation in group S (16 (15-18) s) was significantly faster than in group C (22 (19-24) s, P < 0.0005; 95% CI for difference: 3-7 s). Cricoid pressure after insertion of the laryngeal mask makes tracheal intubation through the mask significantly more difficult.
我们研究了70例患者，以观察喉罩插入后施加环状软骨压迫是否会改变经喉罩气管插管的成功率。在麻醉诱导和神经肌肉阻滞之后，将患者随机分为接受环状软骨压迫组（C组）或假压迫组（S组）。在施加测试压力前后评估通过喉罩观察声门的视野，并尝试使用纤维支气管镜经喉罩进行气管插管。测试压力未改变S组任何患者的声门视野，而C组35例患者中有16例声门孔径变窄。S组所有患者和C组25例患者的纤维支气管镜插入了气管。S组（31例患者）气管插管的成功率显著高于C组（21例患者，P << 0.001；差异的95%置信区间：9 - 48%）。S组插入纤维支气管镜的时间（中位数（95%置信区间）：12（11 - 12）秒）显著快于C组（16（14 - 17）秒，P << 0.001；差异的95%置信区间：3 - 6秒），且S组气管插管的时间（16（15 - 18）秒）显著快于C组（22（19 - 24）秒，P < 0.0005；差异的95%置信区间：3 - 7秒）。喉罩插入后施加环状软骨压迫会使经喉罩气管插管显著更加困难。
