The Use of Intranasal Nitroglycerin to Prevent Pressor Responses during Intubation in General Anesthesia - A Comparison of Various Doses

Background: Intranasal nitroglycerin (NTG) was first reported to successfully prevent an increase in arterial blood pressure following laryngoscopy and tracheal intubation by Hill et al. Various different effective dosages of NTG have been reported. Grover et al. indicated 0.75 mg of intranasal NTG to be the most suitable dose. However, no definite conclusion has yet been made. This study was designed to compare the efficacy of four different dosages of intranasal NTG (0.3, 0.5, 0.75, and 1.0 mg) in preventing pressor responses to laryngoscopy and tracheal intubation during the induction of general anesthesia. Methods: One hundred patients (ASA I or II) scheduled for elective surgery were included. These study subjects were divided into five groups and randomly assigned to four different dosages of intranasal NTG and a placebo. Each group consisted of 20 patients. The NTG solution was administered 1 min before the injection of thiopental. Systolic arterial pressure (SAP), diastolic arterial pressure (DAP), mean arterial pressure (MAP) and heart rate (HR) were recorded before the induction of anesthesia (T_1), before laryngoscopy (T_2), and at 0, 3, and 5 min after tracheal intubation (T_3, T_4, and T_5 respectively). Results: In patients who received a placebo (control group), there were significant increases in SAP, MAP, HR and rate-pressure-product (RPP) associated with tracheal intubation. Tachycardia was noted in all experimental groups. The increases in MAP associated with tracheal intubation were significantly less in patients who received NTG of 0.5 mg or more but not 0.3 mg. Although 0.5 mg of NTG did attenuate the increases in SAP after tracheal intubation, the increases in SAP of the other three experimental groups were no less than that of the control group. Rate-pressure-product (RPP) values of the experimental groups were noted to be equal to or higher than those of the control group during the period of study. Contrary to the results of the study conducted by Grover et al., 0.75 mg of NTG did not attenuate the pressor responses. Conclusions: Intranasal NTG does not attenuate the pressor responses to laryngoscopy and tracheal intubation.

關鍵字

Anesthetic techniques: laryngoscopy, tracheal intubation ； Pharmacology: intranasal nitroglycerin

並列摘要

背景：全身麻醉進行氣管內插管時常見反射性頻脈及高血壓，此一過度性變化若發生於高血壓式冠狀動脈疾病的病人，可引起心肌梗塞或左心室衰竭；硝基甘油（nitroglycerin）可降低心肌負荷，改善冠狀動脈血流及心肌血氧供應；目前硝基甘油有各種不同的製劑，如舌下製劑、藥膏製劑或靜脈製劑等；不同的製劑均有其不足之處，如靜脈製劑之昂貴及不穩定性、而在氣管內插管及oral airway存在時之不易施用舌下製劑，均造成臨床上使用之限制，鼻腔內施用硝基甘油可克服上述的問題。根據Hill等人的報告，鼻腔內施用硝基甘油能有效減緩上述反射性頻脈及高血壓；而Grover等人亦報告0.75 mg是一較佳劑量，但是目前對劑量並無定論。將舌下製劑溶於生理鹽水中經鼻腔給藥，是一簡便而有效之方法，其療效與作用機轉跟靜脈給藥相似。方法：本實驗乃是對一百位ASA I-II預訂接受常規性手術之患者，分五組接受鼻腔內拖用不同劑量之硝基甘油（0 mg，0.3 mg，0.5 mg，0.75 mg，及1.0 mg）以監測於全麻時進行氣管內插管所引起之血波動力學變化；測量之指數包括收縮壓（SAP）、舒張壓（DAP）、平均動脈壓（MAP）、心跳速率（HR）及rate-pressure-product（RPP），另外亦同時監測其心電圖（EKG）及血氧飽和比（SpO_2）之變化。結果：鼻腔內施用硝基甘油之後，0.5 mg或更高之劑量的硝基甘油可以有效減緩插管後平均動脈壓之上升，但0.3 mg則無此作用；四種實驗劑量中只有0.5 mg可以緩解插管後收縮壓上升的情況；另外頻脈在四組實驗組中均存在。RPP可代表患者血液動力學之綜合表現，四組實驗組中的RPP數值均未低於對照組之數值，此外0.75 mg並未如Grover等人所言可緩解插管時之血液動力學反應。結論：不論劑量為何，硝基甘油均無法有效緩解插管時引起之血液動力學反應。

並列關鍵字

麻醉技術：喉鏡；氣管內插管；藥理學：鼻腔內稍基甘油

國際替代計量

The Use of Intranasal Nitroglycerin to Prevent Pressor Responses during Intubation in General Anesthesia - A Comparison of Various Doses

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