Department of Anesthesiology and Pain Medicine, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro 43-gil, Songpa-gu, Seoul, 05505, South Korea.
Sci Rep. 2022 Jan 11;12(1):521. doi: 10.1038/s41598-021-04457-4.
Applying a pneumatic tourniquet provides surgeons with a bloodless surgical field. However, application of the tourniquet induces various physiological changes. We evaluated the effect of tourniquet deflation on the intracranial pressure by using ultrasonography to measure the optic nerve sheath diameter (ONSD) in patients undergoing lower limb surgery. The ONSD was measured in 20 patients at five time points: after anesthetic induction (T0) and immediately before (T1), immediately after (T2), 5 min after (T3), and 10 min after tourniquet deflation (T4). Hemodynamic and respiratory variables were recorded. The ONSD showed significant differences at each point (P < 0.001). The ONSDs at T2 and T3 were significantly greater than that at T1 (P = 0.0007 and < 0.0001, respectively). The change in the end-tidal carbon dioxide partial pressure (EtCO2) was similar to the change in the ONSD. The change in the ONSD was significantly correlated with the change in the EtCO2 after tourniquet deflation (r = 0.484, P = 0.030). In conclusion, the ONSD, as an indicator of intracranial pressure, increased after tourniquet deflation in patients undergoing lower limb surgery. This was correlated with an increased EtCO2 and arterial carbon dioxide partial pressure.Trial registration: ClinicalTrials.gov (NCT03782077).
应用气压止血带可为外科医生提供无血手术视野。然而，止血带的应用会引起各种生理变化。我们通过使用超声测量视神经鞘直径（ONSD）来评估下肢手术患者止血带放气对颅内压的影响。在 20 名患者中，在五个时间点测量了 ONSD：麻醉诱导后（T0）和（T1）之前、（T2）之后、（T3）之后 5 分钟和（T4）之后 10 分钟。记录血流动力学和呼吸变量。每个时间点的 ONSD 均有显著差异（P < 0.001）。T2 和 T3 时的 ONSD 明显大于 T1（P = 0.0007 和 < 0.0001）。呼气末二氧化碳分压（EtCO2）的变化与 ONSD 的变化相似。止血带放气后 ONSD 的变化与 EtCO2 的变化显著相关（r = 0.484，P = 0.030）。结论：下肢手术患者止血带放气后，颅内压的 ONSD 增加。这与 EtCO2 和动脉二氧化碳分压的增加有关。试验注册：ClinicalTrials.gov（NCT03782077）。
