Dexmedetomidine infusion for sedation during awake intubation

Dexmedetomidine (DEX) is a selective alpha-2 adrenergic agonist that has been used clinically for its analgesic and sedative effects. We report a case of awake intubation with DEX. A 38-year-old male patient with 130 kg in weight, 170 cm in height and with a body mass index of 45 presented with thoracic myelopathy and progressive bladder and bowel control difficulties. Posterior decompression for thoracic myelopathy was planned. He was placed on the operating table with application of routine monitors. DEX infusion was commenced at 5 mcg x kg(-1) x hr(-1) over 10 minutes. Additional DEX at 0.1 mcg x kg(-1) was given 3 times because the patient still felt anxious. During DEX administration, topical anesthesia in the oropharynx, hypopharynx and glottis was achieved using lidocaine 8% spray. The patient was intubated without coughing, movement of limbs or respiratory depression. At the start of laryngoscopy, the patient had a Ramsay sedation score of 6. It was found by pharmacokinetic simulation analysis that the plasma concentration of DEX at intubation was 5.6 ng x ml(-1). We concluded that DEX is a reasonable medication during awake intubation, although further investigations with regard to its safety are required.     

Dexmedetomidine for conscious sedation in difficult awake fiberoptic intubation cases

Currently used methods of sedation for fiberoptic intubation such as benzodiazepines, propofol, or opioids have their limitations. Dexmedetomidine (DEX) is a selective alpha-2 adrenergic agonist that has been used clinically for its sympatholytic, analgesic, and sedative properties. We report on 4 patients with particularly difficult airways who underwent successful awake fiberoptic intubation with DEX. Dexmedetomidine was used to provide a moderate level of conscious sedation without causing respiratory distress or hemodynamic instability during fiberoptic intubation.     

Remifentanil for conscious sedation and analgesia during awake fiberoptic tracheal intubation: a case report with pharmacokinetic simulations.

We report a case of awake, fiberoptic tracheal intubation of a difficult airway (Ludwig's angina) using remifentanil as part of the sedation-analgesia regimen. Remifentanil's rapid onset-rapid offset pharmacokinetic profile enabled precise control of the level of opioid effect. In combination with other drugs, remifentanil may offer some clinical advantages compared to the other fentanyl congeners in providing the opioid component of conscious sedation-analgesia for awake tracheal intubation in patients with difficult airways.     

右美托咪定用于老年患者纤维支气管镜气管插管剂量的探讨

目的观察右美托咪定（dexmedetomidine,Dex）用于老年患者纤维支气管镜（纤支镜）插管的临床效果,并探讨其最佳剂量。方法选择120例65～90岁ASA分级Ⅱ、Ⅲ级拟行纤支镜插管的患者,采用随机数字表法将患者分为D1、D2、D3、D4组（每组30例）,分别于10rain内输注负荷量为0．2、0．4、0．6、0．8μg／kgDex,然后4组患者均按0．2μg·kg^-1·h^-1Dex维持,记录入室时（T0）、插管前（T1）、纤支镜经声门即刻（T2）、插管后1min（T3）、插管后3min（T4）、插管后10min（T5）的MAP、HR和警觉与镇静评分（observer＇s assessment of alertness/sedation,OAA／S）,并记录插管所用时间,评价插管耐受度、满意度。结果与T0时点比较,T1-T5时点Dl、D2、D3、D4组OAA／S评分明显降低（P〈0．05）,D2、D3、D4组MAP明显降低（P〈0．05）,T2时点的Dl组和D2组HR明显增快（P〈0．05）,D3组和D4组HR明显降低（P〈0．05）;与Dl组比较,T2～B时点D3组和D4组OAMS评分、HR和MAP明显降低（P〈0．05）;与D2组比较,即T4-T5时点D4组OAA／S评分明显降低,T2～T5时点D4组MAP和HR明显降低。4组的插管成功率均为100％,D2、D3、D4组插管时间短于Dl组（P〈O．05）,插管耐受度和满意度均优于D1组（P〈0．05）。结论Dex用于老年患者纤支镜插管时,使用负荷剂量0．4～0．6μg／kg镇静充分,而且对呼吸、循环系统影响小。     

Dexmedetomidine and awake fiberoptic intubation for possible cervical spine myelopathy: a clinical series

For many anesthesiologists, awake fiberoptic endotracheal intubation (AFOBI) is the preferred method of intubation when treating patients with symptoms or signs of cervical spinal cord compression. The advantage of this method is to minimize cervical spine movements that could contribute to neurologic impairment. In patients who are anxious or poorly cooperative, adequate sedation in addition to topicalization of the airway may be key to minimize patient discomfort and assist in successful intubation, but imposes the risk of respiratory depression. Dexmedetomidine has the advantage of producing sedation without a significant decrease in respiratory drive. We are now reporting our experience of a series of AFOBI using dexmedetomidine for sedation. A retrospective chart review was conducted on the anesthetic records of patients, who had undergone an awake fiberoptic endotracheal intubation (AFOBI) using dexmedetomidine for sedation. These were patients in whom AFOBI was indicated because of signs or symptoms of cervical spinal cord compression. Dexmedetomidine provided adequate sedation. We did not encounter any loss of airway or airway obstruction during the intubation. The patients had excellent cooperation for post-intubation neurologic examination. Thirteen patients developed transient hypotension after induction of general anesthesia that was managed with boluses of phenylephrine or ephedrine.     

Dexmedetomidine infusion overdose during anesthesia: A case report

A 12‐kg infant was given intravenous dexmedetomidine 0.2 µg kg^‐1 min^‐1 as an adjunct for general anesthesia. The 60‐fold increase in dexmedetomidine infusion rate caused a biphasic response with initial hypertension followed by bradycardia and hypotension requiring inotropic support. No postoperative or long‐term sequelae were noted. Dexmedetomidine infusion is usually delivered as µg kg^‐1 h^‐1.     

Dexmedetomidine and ketamine for fiberoptic intubation in a child with severe mandibular hypoplasia

A 6-year-old girl with Treacher Collins syndrome presented for implantation of a hearing device. The patient was developmentally delayed and had severe micrognathia. After induction of anesthesia with dexmedetomidine and ketamine, the patient tolerated the introduction of a flexible fiberoptic bronchoscope without any change in respiration, and intubation was achieved easily.     

Dexmedetomidine for pediatric MRI sedation: a review of a series of cases

BACKGROUND: The aim of this review was to determine whether dexmedetomidine alone provided satisfactory conditions for children undergoing magnetice resonance imaging (MRI). METHODS: A retrospective review of 21 patients was undertaken, (age range: 1-8 years, weight 10-27 kg) who received dexmedetomidine to provide deep sedation for an MRI procedure. RESULTS: In the initial eight patients who received dexmedetomidine (bolus 0.5-1.5 mg.kg(-1) and infusion rate 1-1.5 mg.kg(-1).h(-1)) by itself, movement occurred in five of them, even when the maximum suggested dose was used (1 microg.kg(-1).h(-1)). Midazolam (0.1 mg.kg(-1)) i.v. was given as an adjunct to the following 13 patients (dexemdetomidine doses were lower: bolus 1 mg.kg(-1), infusion 0.5-1 mg.kg(-1).h(-1)). Only one patient moved within this group. The mean time to discharge postprocedure was 90 min. There were no differences with respect to recovery or discharge times between those who did or did not receive midazolam. No cardiac or respiratory complications were noted. CONCLUSIONS: The use of dexmedetomidine for MRI sedation by itself was more unpredictable than anticipated from the published case reports of its use.     

Dexmedetomidine and low-dose ketamine provide adequate sedation for awake fibreoptic intubation

PURPOSE: We report the use of the alpha2 agonist, dexmedetomidine, with low-dose ketamine as a safe and effective treatment strategy to provide adequate comfort and sedation for a patient who fulfilled criteria of a difficult airway and required awake fibreoptic intubation (AFOI). CLINICAL FEATURES: A 52-yr-old male with prostate cancer presented for radical prostatectomy. He reported several failed intubations with previous surgeries and airway examination was consistent with a difficult intubation. In addition, previous fibreoptic intubations were unsuccessful. The patient reported extreme apprehension concerning his airway management. The goal of medicating patients for AFOI includes providing comfort and sedation without causing a change in ventilatory status. Dexmedetomidine has a high affinity for the alpha2 receptor and results in sedation without change in ventilatory status. In addition, dexmedetomidine is a potent anti-sialgogue which makes it desirable for cases involved with airway instrumentation. A loading dose of dexmedetomidine followed by a continuous infusion provided comfort and sedation within ten minutes. While bradycardia and hypotension have been reported with dexmedetomidine use, concurrent low-dose ketamine was employed in this case for it's cardiostimulatory properties and no bradycardia and hypotension were noted. The airway was anesthetized with selective nerve blocks and conditions for airway instrumentation were excellent. There was no change in oxygen saturation or ventilatory status during the administration of medications or airway manipulation. The patient was comfortable, sedated and tolerated the procedures well. There was no recall of the procedure. CONCLUSION: Dexmedetomidine and concurrent low-dose ketamine provided sedation and comfort to this patient who required an AFOI.     

Dexmedetomidine as sole agent for awake fiberoptic intubation in a patient with local anesthetic allergy

A series of case reports acknowledges the efficacy of dexmedetomidine as a sole sedative for awake intubations in managing a critical airway. However, most case reports documented in the literature used topicalization of the oropharynx either via nebulized lidocaine or the spray-as-you-go technique with either 2% or 4% lidocaine spray to achieve successful intubation. The following case report presents an intensive care unit (ICU) patient with a critical airway who had a true documented allergy to local anesthetics. This case report demonstrates that dexmedetomidine appears to be useful for sedation during awake intubations in critical airways, without the need for airway topicalization. The ability of dexmedetomidine to act as a sedative, anxiolytic, analgesic, and antisialagogue without causing respiratory depression is promising to the field of anesthesiology. Additional studies are needed to elucidate its potential role as the sole agent for awake fiberoptic intubation.     

A comparative study of dexmedetomidine with midazolam and midazolam alone for sedation during elective awake fiberoptic intubation

Study ObjectiveTo evaluate the efficacy of dexmedetomidine with midazolam (DEX-MDZ) versus midazolam only (MDZ) for sedation during awake fiberoptic intubation (AFOI).DesignRandomized, double-blinded study.SettingAcademic medical center.Subjects55 ASA physical status I, II, III, and IV patients, aged 18-85 years, scheduled for non-emergency surgery with AFOI.InterventionsAll patients received intravenous (IV) glycopyrrolate 0.2 mg premedication, oxygen by nasal cannula, and topical local anesthetics to the airway. MDZ subjects received IV midazolam 0.05 mg/kg with additional doses to achieve a Ramsay Sedation Scale (RSS) score of ≥ 2. DEX-MDZ patients received midazolam 0.02 mg/kg followed by dexmedetomidine one μg/kg, then an infusion of dexmedetomidine 0.1 μg/kg/hr and titrated to 0.7 μg/kg/hr to achieve RSS≥2.MeasurementsObservers' Assessment of Alertness/Sedation (OAA/S) and RSS were evaluated. The anesthesiologist rated AFOI ease of placement. Two observers rated patients' comfort and reaction to placement at three time points: preoxygenation, at introduction of the fiberoptic laryngoscope, and at introduction of the endotracheal tube (ET) before surgery. Following surgery, patients were asked if they recalled the AFOI and also to rate their satisfaction with the intubation.ResultsDEX-MDZ patients were significantly calmer and more cooperative during AFOI and had fewer adverse reactions to AFOI than did the MDZ patients. They also were more satisfied with the AFOI (P < 0.001) than were the midazolam-only patients. There were no significant hemodynamic differences between the two subject groups.ConclusionsDexmedetomidine in combination with low doses of midazolam is more effective than midazolam alone for sedation in AFOI.     

Dexmedetomidine sedation for awake tracheotomy: case report and literature review

The safe administration of conscious sedation in a patient with a critical airway who underwent awake tracheotomy using dexmedetomidine, a selective alpha₂-agonist with sympatholytic, anxiolytic, analgesic, and sedative properties, is presented. Unlike other commonly used sedative agents, dexmedetomidine provided adequate sedation with minimal respiratory depression.     

Dexmedetomidine for awake fiberoptic intubation in a parturient with spinal muscular atrophy type III for cesarean delivery

Spinal muscular atrophy in pregnancy is rare and poses multiple problems for the anesthesiologist. The effects of dexmedetomidine on a parturient with spinal muscular atrophy have not previously been reported. There are also no in vivo data on placental transfer of dexmedetomidine and its effects on a human neonate. We report the hemodynamic, respiratory and sedative effects of dexmedetomidine on a parturient and neonate when used for awake fiberoptic intubation before cesarean section. A 35-year-old, gravida 4 para 0 aborta 3, 41-kg parturient at 35 weeks of gestation with spinal muscular atrophy presented for cesarean section. Dexmedetomidine was administered intravenously, total dose 1.84 μg/kg over 38 minutes, followed by fiberoptic endotracheal intubation. Dexmedetomidine was then discontinued and general anesthesia was induced. The baby was delivered 68 minutes after the dexmedetomidine infusion was discontinued at which time blood samples were obtained for measurement of dexmedetomidine. During administration of dexmedetomidine, maternal heart rate, blood pressure and oxygen saturation remained stable. Apgar scores at 1 and 5 min were 6 and 8. The fetal concentration of dexmedetomidine (540 pg/mL) indicates significant placental transfer, but significant adverse neonatal effects were not observed. Dexmedetomidine alone provided adequate sedation for awake intubation without respiratory compromise in this patient.     

Laryngeal trauma during awake fiberoptic intubation

IMPLICATIONS: We describe three patients with difficult airways in which fiberoptic endotracheal intubation was used to insert breathing tubes into the patients' windpipes. Airway injury occurred during the use of this technique. Although largely a safe technique, care should be exercised when anesthesiologists choose equipment and when they perform this technique.     

Tracheal bleeding during awake fiberoptic intubation

Fiberoptic intubation can cause laryngeal injury during blind insertion of a tracheal tube. A patient with hypopharyngeal cancer was scheduled for laser surgery and we selected nasal fiberoptic intubation due to laryngeal deformity. Just after insertion of a tracheal tube, tracheal bleeding occurred and ventilation because difficult. Emergency tracheostomy was required to restore adequate oxygenation. A piece of mucosa and blood clot was found in the lumen of the tracheal tube and hematoma was observed on the surface of arytenoid cartilage. Careful selection and optimal manipulation of the tracheal tube is important and surgical airway access should be immediately available before fiberoptic procedure in a patient with friable and vascular-rich laryngeal lesion.     

Remifentanil target-controlled infusion vs propofol target-controlled infusion for conscious sedation for awake fibreoptic intubation: a double-blinded randomized controlled trial

BACKGROUND: Awake fibreoptic intubation (AFOI) is a technique used in patients with difficult airways. This study compares the suitability of remifentanil target-controlled infusion (TCI) to propofol TCI for conscious sedation during AFOI in patients with bona fide difficult airways. METHODS: We recruited 24, ASA I-III patients, who were undergoing sedation for elective AFOI. Patients were randomized to one of the two groups, Group P (n=10) received propofol TCI and Group R (n=14) received remifentanil TCI. Primary outcome measures were conditions achieved at endoscopy, intubation, and post-intubation, which were graded using scoring systems. Other parameters measured were the endoscopy time, intubation time, and number of attempts at intubation. A postoperative interview was conducted to determine recall of events and level of patient satisfaction. RESULTS: Endoscopy scores (0-5) and intubation scores (0-5) were significantly different [Group P 3 (1-4) vs Group R 1 (0-3) P<0.0001, Group P 3 (2-4) vs Group R 1 (0-3) P<0.0001, respectively]; with much better conditions in Group R, endoscopy times and intubation times were also significantly different, being shorter in Group R (P<0.007 and P<0.023, respectively). Patient tolerance of the procedure, judged by the discomfort scores (P<0.004) and the post-intubation scores (P<0.08), was significantly better in Group R. The level of recall for events was higher in Group R. However, there were no significant differences in the patient satisfaction scores. CONCLUSIONS: Remifentanil TCI appears to provide better conditions for AFOI when compared with propofol TCI. The disadvantage of remifentanil in this setting may be a higher incidence of recall.     

右美托咪定同时靶控输注丙泊酚用于慢诱导纤维支气管镜引导经鼻气管内插管术的临床观察

目的 观察右美托咪定(dexmedetomidine,Dex)同时靶控输注(target controlled infusion,TCI)丙泊酚用于慢诱导纤维支气管镜(fiberoptic bronchoscopy,FOB)引导经鼻气管内插管术的可行性和安全性. 方法 拟行全身麻醉下颌面部肿瘤切除术的患者143例,年龄18～65岁,BMI 18～30 kg/m2,ASA分级Ⅰ、Ⅱ级,完全随机分为丙泊酚TCI组(P组,65例)和Dex组(D组,78例).入室后两组均静脉注射芬太尼1.5 μg/kg,TCI丙泊酚,丙泊酚初始血浆靶浓度(plasma concentration,Cp)为1.0 mg/L.D组同时负荷输注Dex(0.5μg/kg,10 min).根据BIS调整丙泊酚Cp.BIS值降至85时环甲膜穿刺注射2％丁卡因2.5 ml,1％丁卡因2ml行鼻腔黏膜表面麻醉.BIS值降至80～70时放置FOB.FOB进入声门后,两组均静脉注射丙泊酚1 mg/kg,放置气管导管并确定其位置,完成麻醉诱导.记录插管术中及术后情况,记录入室安静后(To)、BIS值降至85时(T1)、环甲膜穿刺后即刻(T2)、BIS值降至80～70时(T3)、FOB放置成功时(T4)和气管内插管成功时(T5)的HR、MAP、Sp02和BIS,记录T1和T3时丙泊酚效应室浓度(effect-site concentration,Ce). 结果 两组气管内插管难易度评分、气管内插管时间、呛咳或误吸率差异均无统计学意义(P＞0.05);与P组比较,D组气道阻塞评分升高(48/7/20/3/0比45/16/4/0/0)、舒适度升高(62/16/0/0/0比35/29/0/1/0)、插管记忆评分升高(60/18/0比62/3/0)、术后咽痛评分升高(22/55/1/0比41/20/4/0),D组血流动力学更稳定,差异有统计学意义(P＜0.05).两组患者T1时丙泊酚Ce差异无统计学意义(P＞0.05);与P组比较,D组T3时丙泊酚Ce降低[(1.00±0.20) mg/L比(1.10±0.30)mg/L](P＜0.05). 结论 负荷剂量Dex(0.5 μg/kg,10 min)辅助表面麻醉用于慢诱导FOB引导经鼻气管内插管可降低丙泊酚的Ce,舒适度更高,但应注意气道阻塞、插管知晓和术后咽痛等并发症.