作者：Caroline Helwick
出處：WebMD醫學新聞
October 23, 2009（紐奧良）－根據一項發表於2009年美國麻醉醫學會的研究結果，dexmedetomidine可以安全地加速持續焦躁病患脫離呼吸器時程。
資深作者加州舊金山綜合醫院的Julin F. Tang醫師解釋，接受呼吸器輔助呼吸病患經常需要鎮靜安眠藥物，而突然降低劑量可能造成嚴重焦躁，以及血行動力學過度興奮的變化，這些都可能必須重新回到之前的鎮靜安眠深度。第一作者是Po Liang Chen醫師。
Dexmedetomidine是一個高度選擇性的alpha-2受體制效劑，在術前降低麻醉藥物與止痛藥物需求量，它也可以抑制中樞神經系統的交感神經活性，降低血壓與心跳速率。
舉例來說，我們經常有這樣的病患，例如外傷病患，他們是很焦躁的，無法輕易地脫離呼吸器與propofol、midazolam、lorazepam或是止痛藥物。Tang醫師解釋，我們停止使用這些藥物，但是我們在隔天必須再用並且注射這些藥物。現在，我們減少使用這些藥物，並且改用dexmedetomidine。我們發現這可以加速拔管速度，且相較於多花時間讓病患接受呼吸器輔助呼吸，可能比較便宜。
他們的團隊以一項前瞻性、隨機分派控制研究，正式地評估外科加護病房60位病患接受這種治療方法的價值。在這項會議中，他發表前20種病患的數據。被隨機分派到控制組的病患，根據各機構標準脫離呼吸器計畫拔管；那些在實驗組的病患們也接受dexmedetomidine 0.5或0.7 mcg/kg/hr持續輸注。
兩組病患的情況在試驗前是相似的，除了Ramsay鎮靜指標（RSS）分數，在dexmedetomidine組的分數較低（2.1±1.1比上3.5±1.2；P<0.01）。研究者們目前並沒有起始點的疾病嚴重度分數，但是將在未來的分析中報告。
背景鎮靜安眠藥物與止痛藥物劑量逐漸降低，且在脫離呼吸器前使用噴霧lidocaine。隨機分派接受dexmedetomidine病患在拔管後2小時內繼續接受這個藥物。
脫離呼吸器過程中與2小時間持續監測動脈血氧、生命徵象與其他量測指標。
【加上Dexmedetomidine後比較容易脫離呼吸器】
拔管後，接受dexmedetomidine病患們的二氧化碳分壓比較高（41.2±6.9比上37.5±1.5 mmHg；P=0.04），且RSS分數較低（2.1±0.6比上3.1±1.1；P=0.02）。
Tang醫師報告，重要的，在這組需要完全拔管的時間顯著較短（2.0±1.1相較於46.0±72.5小時；P=0.04）。
他觀察到，使用dexmedetomidine，拔管時間非常短。
Dexmedetomidine組使用呼吸器時間（從開始研究到拔管）顯著較短（59.2±139.4相較於203.9±150.7小時；P=0.02）。他表示，這樣的差異大概是從9天到2~3天。
Chen醫師報告，在研究結束時，成功拔管的機率（不需再重新插管），在dexmedetomidine組顯著較高。10位病患中有8位成功脫離呼吸器，控制組10位中僅有3位（P=0.01）。
在dexmedetomidine組，住在ICU的時間有顯然較短的趨勢，但是這個差異並未達到統計上顯著差異（9.8±9.8比上19.5±16.9天；P=0.06）。
Tang醫師的結論是，對於過去脫離呼吸器失敗的焦躁病患，使用dexmedetomidine看起來是安全的，且對於拔管是有幫助的，拔管時間較短、使用呼吸器時間較短、且成功拔管機率較高。
【Dexmedetomidine對於拔管的影響】
| 控制組（ 10 位） | Dexmedetomidine 組（ 10 位） | P 值 |
拔管時間（小時） | 46.0±72.5* | 2.0±1.1 + | .04 |
使用呼吸器時間（小時） | 203.9±150.7 | 59.2±139.4 | .02 |
拔管人數（人） | 3 | 8 | .01 |
ICU 住院時間（天） | 19.5±16.9 | 9.8±9.8 | .06 |
*8位
+9位
在座談會中擔任引言人的伊利諾州芝加哥大學醫學中心重症照護主任與麻醉副教授Avery Tang醫師表示，目前在ICU的鎮靜安眠藥物研究，重點在於避免譫妄的藥物選擇。這裡，dexmedetomidine成功地控制病患精神狀況，且加速拔管時程。如果這樣的研究結果經過確效，代表這個藥物可能可以用於最佳化這種狀況下的醫療照護。
Tang醫師表示接受Hospira的經費贊助。Tung醫師表示已無相關資金上的往來。
Dexmedetomidine Facilitates Extubation in Agitated SICU Patients
By Caroline Helwick
Medscape Medical News
October 23, 2009 (New Orleans, Louisiana) — Dexmedetomidine can safely facilitate weaning from mechanical ventilation in patients with prolonged agitation, according to a study presented here at the American Society of Anesthesiologists 2009 Annual Meeting.
Mechanically ventilated patients often require sedation, and its abrupt reduction can cause severe agitation and hyperhemodynamic changes that necessitate a return to previous levels of sedation, explained the study's senior author, Julin F. Tang, MD, from San Francisco General Hospital in California. The first author was Po Liang Chen, MD.
Dexmedetomidine is a highly selective α2-receptor agonist that reduces anesthetic and analgesic requirements perioperatively. It also inhibits sympathetic activity in the central nervous system, lowering blood pressure and heart rate.
"Quite often we have individuals — for example, trauma patients — who are agitated and cannot be easily weaned off ventilation with propofol, midazolam, lorazepam, narcotics. We stop these drugs, but then we need to put them back on and shoot for the next day," Dr. Tang explained. "Now, we reduce the drugs and transition patients to dexmedetomidine. We have found that this facilitates extubation and it is probably much less expensive than spending another day on ventilation."
His group is formally assessing the value of this approach in 60 patients in the surgical intensive care unit (ICU) in a prospective randomized controlled study. At the meeting, he presented data on the first 20 patients. Patients randomized to the control group were extubated according to the hospital's standard weaning protocol; those in the experimental group also received dexmedetomidine 0.5 or 0.7 μg/kg per hour.
The groups were similar at baseline, except Ramsay Sedation Scale (RSS) scores in the dexmedetomidine group were lower (2.1 ± 1.1 vs 3.5 ± 1.2; P < .01). The investigators do not currently have data on baseline Illness Severity Scores, but this is planned for future analyses.
Background sedation and analgesia were gradually titrated down and aerosolized lidocaine was initiated prior to weaning. The dexmedetomidine group continued to receive the drug for about 2 hours after extubation.
Arterial blood gases, vital signs, and other measures were obtained throughout the extubation process and for the subsequent 2 hours.
Weaning Was Easier With Addition of Dexmedetomidine
After extubation, patients receiving dexmedetomidine had higher partial pressure of carbon dioxide (41.2 ± 6.9 vs 37.5 ± 1.5 mm Hg; P = .04) and lower RSS scores (2.1 ± 0.6 vs 3.1 ± 1.1; P = .02).
Importantly, the time required to complete the extubation was distinctly shorter in this group (2.0 ± 1.1 vs 46.0 ± 72.5 hours; P = .04), Dr. Tang reported.
"With dexmedetomidine, this was very quick," he observed.
Time on the ventilator (determined from the start of the study to extubation) was shorter in the dexmedetomidine group (59.2 ± 139.4 vs 203.9 ± 150.7 hours; P = .02). "This is a difference of about 9 days to about 2 or 3," he noted.
At the end of the study, the rate of successful extubation (without reintubation) was significantly higher with dexmedetomidine. Eight of 10 patients were successfully weaned, compared with 3 of 10 patients in the control group (P = .01), Dr. Chen reported.
There appeared to be a trend for a shorter ICU stay in the dexmedetomidine group, but the difference was not statistically significant (9.8 ± 9.8 vs 19.5 ± 16.9 days; P = .06).
"The use of dexmedetomidine seems safe and beneficial in extubating agitated patients previously failing weaning attempts, with shorter extubation time, fewer ventilator days, and more successful extubation," Dr. Tang concluded.
Impact of Dexmedetomidine on Extubation | Control Group (n = 10) | Dexmedetomidine Group (n = 10) | P value |
| Extubation time (hours) | 46.0±72.5* | 2.0±1.1? | .04 |
| Ventilator time (hours) | 203.9±150.7 | 59.2±139.4 | .02 |
| Extubation (n) | 3 | 8 | .01 |
| Length of ICU stay (days) | 19.5±16.9 | 9.8±9.8 | .06 |
*n = 8
?n = 9
Avery Tung, MD, associate professor of anesthesiology and director of Critical Care Services at the University of Chicago Medical Center, in Illinois, who moderated the session, said: "Current research on ICU sedation is focusing on the use of drug choice to avoid delirium. Here, dexmedetomidine was successfully used to control the mental state and facilitate extubation. If the results can be validated, it suggests that it may be used to optimize medical care in this setting."
Dr. Tang reports receiving grant support from Hospira. Dr. Tung has disclosed no relevant financial relationships.
American Society of Anesthesiologists (ASA) 2009 Annual Meeting: Abstract A1578. Presented October 21, 2009.
