Previously published midazolam-alfentanil response surface model cannot predict patient response well in gastrointestinal endoscopy sedation

详细信息    查看全文

• 作者：Jing-Yang Liou^a ; Chien-Kun Ting^a ; ^b ; Yu-Ying Huang^c ; Mei-Yung Tsou^a ; ^b ; ^{mytsou8095@gmail.com" class="auth_mail" title="E-mail the corresponding author}
• 关键词：alfentanil ; gastrointestinal endoscopy ; midazolam ; pharmacodynamic ; response surface model
• 刊名：Journal of the Chinese Medical Association
• 出版年：2016
• 出版时间：March 2016
• 年：2016
• 卷：79
• 期：3
• 页码：146-151
• 全文大小：908 K

文摘

A response surface model is a mathematical model used to predict multiple-drug pharmacodynamic interactions. With the use of a previously published volunteer model, we tested the accuracy of the midazolam–alfentanil response surface model during gastrointestinal endoscopy.

Methods

We enrolled 35 adult patients scheduled for combined endoscopic procedures. Patients were sedated with intravenous midazolam and alfentanil, and monitored with real-time auditory evoked potential. Sedation Observer's Assessment of Alertness/Sedation (OAA/S) scores were recorded by an independent observer every 2 minutes. Patients with OAA/S scores of ≥4 were designated as “awake”. Pharmacokinetic profiles were calculated using the TIVA trainer. The published response surface model was modified to make estimations more reasonable. Patient response (OAA/S score ≥ 4 or <4) was then estimated using the modified version of the model.

Results

The average procedural times were 3.3 ± 2 minutes and 6.5 ± 2.3 minutes for esophagogastroduodenoscopy and colonoscopy, respectively. The model poorly predicted patient response during gastrointestinal endoscopic procedure sedation. Accuracy in predicting an OAA/S score of <4 was 6% for the original model and 0% for the modified model. The estimated probability of loss of response ranged from 0.04% to 2.94% at the time of arousal (OAA/S score ≥ 4) and from 0.24% to 15.55% when the patient was asleep (OAA/S score < 4).

Conclusion

The model showed significant synergy between midazolam and alfentanil; however, it was inadequate in predicting the response of patients undergoing sedated gastrointestinal endoscopic procedures. Future model parameter adjustments are required.