Date Published: June 11, 2019
Publisher: Public Library of Science
Author(s): Ji-Hye Kwon, Young Hee Shin, Nam-Su Gil, Jungchan Park, Yoon Joo Chung, Tae Soo Hahm, Ji Seon Jeong, Wisit Cheungpasitporn.
During emergence from general anesthesia, coughing caused by the endotracheal tube frequently occurs and is associated with various adverse complications. In patients undergoing endovascular neurointervention, achieving smooth emergence from general anesthesia without coughing is emphasized since coughing is associated with intracranial hypertension. Therefore, the up-and-down method was introduced to determine the effective effect-site concentration (Ce) of remifentanil to prevent coughing in 50% and 95% (EC50 and EC95) of patients during emergence from sevoflurane anesthesia for endovascular neurointervention. A total of 43 participants, American Society of Anesthesiologists class I or II participants, aged from 20 to 70 years who were undergoing endovascular neurointervention through transfemoral catheter for cerebrovascular disease were enrolled. Using the up-and-down method with isotonic regression, the EC50 and EC95 of remifentanil to prevent coughing during emergence from sevoflurane anesthesia were determined. We also investigated differences of hemodynamic and recovery profiles between the cough suppression group and the cough group. In total, 38 of 43 patients were included for estimation of EC50 and EC95. The EC50 and EC95 of remifentanil to prevent coughing were 1.42 ng/mL (95% confidence interval [CI], 1.28–1.56 ng/mL) and 1.70 ng/mL (95% CI, 1.67–2.60 ng/mL), respectively. There was comparable emergence and recovery data between the cough suppression group (n = 22) and the cough group (n = 16). However, the Ce of remifentanil and total dose of remifentanil were significantly higher in the cough suppression group (P = 0.002 and P = 0.004, respectively). Target-controlled infusion of remifentanil at 1.70 ng/mL could effectively prevent extubation-related coughing in 95% of neurointervention patients, which could ensure smooth emergence.
While emerging from general anesthesia, coughing induced by the endotracheal tube (ETT) frequently occurs and is associated with various adverse complications including intracranial hypertension , increased intraocular pressure , hypertension, and tachycardia . There have been efforts to prevent coughing while emerging from anesthesia, and prevention is emphasized in specific clinical situations.
This prospective study was approved by the Institutional Review Board of Samsung Medical Center (IRB No. SMC 2017-10-061-001) and registered at the Clinical Research Information Service (CRIS, https://cris.nih.go.kr) under the identification number KCT0002691 (date of registration: 12/12/2017). This investigation was conducted at a tertiary medical center, Samsung Medical Center, in Seoul, Korea, between February 2018 and May 2018.
A total of 43 patients were enrolled using Dixon up-and-down methods. Five patients were excluded for delayed emergence and remifentanil discontinuation due to low blood pressure. A total of 38 patients were included for estimation of EC50 and EC95 (Fig 1). Demographic characteristics are reported in Table 1. Figs 2 and 3 demonstrate the up-and-down results in consecutive patients and PAVA response rate, respectively. The EC50 and EC95 of remifentanil as estimated by the isotonic regression model were 1.42 ng/mL (95% CI, 1.28–1.56 ng/mL) and 1.70 ng/mL (95% CI, 1.67–2.60 ng/mL), respectively. The correlation coefficients between Ce of remifentanil and time to extubation and duration of PACU stay were -0.011 and 0.473, respectively (P = 0.95 and P = 0.003).
The main finding of our study is that the EC50 and EC95 of remifentanil to prevent coughing during emergence from sevoflurane anesthesia are 1.42 ng/mL (95% CI, 1.28–1.56 ng/mL) and 1.70 ng/mL (95% CI, 1.67–2.60 ng/mL), respectively, in patients undergoing endovascular neurointervention through transfemoral catheter. When the Ce of remifentanil increased, duration of PACU stay was prolonged, but the time of extubation was not statistically different. Among the patients included in this study, 22 had no coughing (cough suppression group) and 16 experienced coughing (cough group). There were significant differences in Ce of remifentanil and total amount of remifentanil, with higher values in the cough suppression group.
The EC50 and EC95 of remifentanil to prevent coughing for smooth emergence after endovascular neurointervention under sevoflurane anesthesia were 1.42 ng/mL and 1.70 ng/mL, respectively. Our results in this small sample indicate that the remifentanil concentration levels we utilized safely prevented coughing during emergence from sevoflurane anesthesia. The wide confidence intervals for our estimates (in particular, for EC95), however, indicate that a larger study would be useful to increase the precision of concentration levels.