The effect of calcium channel blockers on cerebral oxygenation during tracheal extubation

Calcium channel blockers are effective in stabilizing systemic hemodynamics during tracheal extubation. However, they may increase cerebral blood flow (CBF) during tracheal extubation because of cerebral vasodilation, even if systemic arterial blood pressure decreases. In this study, we observed changes in cerebral oxygenation during tracheal extubation by using near-infrared spectroscopy and evaluated the effect of nicardipine and diltiazem on the resultant changes. We studied 45 women undergoing elective gynecologic surgery. After surgery, the patients were randomly allocated to three groups (n = 15 each): saline (control), 0.02 mg/kg nicardipine, and 0.2 mg/kg diltiazem. After 2 min, we started to aspirate secretions for 2 min and then, extubated the trachea. Changes in cerebral oxygenated hemoglobin (HbO(2)) and deoxygenated hemoglobin were measured during the extubation procedure for 9 min after drug treatment. Systemic hemodynamics, including mean arterial blood pressure, heart rate, end-tidal CO(2), end-tidal sevoflurane concentration, and peripheral arterial oxygen saturation were also monitored. During extubation, HbO(2) increased significantly, presumably caused by the increase in CBF. Changes in deoxygenated hemoglobin were minimal. Compared with the control, nicardipine and diltiazem significantly inhibited the increase in mean arterial blood pressure. On the contrary, they significantly enhanced the increase in HbO(2). In conclusion, calcium channel blockers may increase CBF during extubation, even if these drugs stabilize systemic hemodynamics. Implications: This study is a preliminary report evaluating the changes in cerebral oxygenation during the tracheal extubation. Cerebral oxygenated hemoglobin increased significantly, presumably caused by the increase in cerebral blood flow during extubation. In addition, these changes were enhanced by calcium channel blockers.     

右美托咪定用于气管异物患儿气管拔管的镇静效果

目的 观察术前给予右美托咪定对气管异物取出术患儿气管拔管的镇静效果.方法 气管异物取出术患儿60例,随机均分为两组,分别在全麻诱导前10 min内静脉输注右美托咪定0.5 μg/kg(D组)或生理盐水(C组).术中丙泊酚2mg·kg-1·h-1、瑞芬太尼0.1μg·kg-1·h-1维持麻醉.记录拔管前1 min、拔管时、拔管后1、5min时的HR、MAP、RR、Ramsay镇静评分的变化,以及拔管期间呛咳和躁动情况.结果 D组HR、RR、MAP、呛咳评分和躁动评分低于C组(P＜0.05),Ramsay镇静评分高于C组(P＜0.05).结论 术前给予右美托咪定可为气管异物患儿苏醒期提供较好的镇静,减少拔管期间躁动和呛咳.     

羟考酮对腹腔镜胆囊切除术患者拔管期应激反应、术后疼痛的影响分析

目的分析羟考酮对腹腔镜胆囊切除术患者拔管期应激反应、术后疼痛的影响分析。方法收集行腹腔镜胆囊切除术治疗的患者120例,ASA分级为Ⅰ~Ⅱ级,根据随机数字表法分为4组(每组30例),A、B、C组分别于术前15min静脉注射0.1mg/kg、0.15mg/kg、0.2mg/kg的羟考酮,D组静脉注射相同剂量的生理盐水。比较4组患者术后VAS评分、Ramsay镇静评分和炎性因子水平,并比较4组患者静脉注射羟考酮即刻(T1)、拔管即刻(T2)及拔管后5(T3)、10min(T4)的平均动脉压(MAP)、心率(HR)、血清肾上腺素(E)、皮质醇(Cor)水平。结果 C组拔管时间、苏醒时间明显高于A组、B组和D组(P0.05);B组、C组T2、T3时刻MAP、HR均明显低于A组和D组(P0.05);B组、C组T2、T3、T4时刻血清E、Cor水平明显低于A组和D组(P0.05);B组、C组术后1、2、6h的VAS评分明显低于A组和D组(P0.05);C组术后1、2、6h的Ramsay评分明显高于A组、B组和D组(P0.05);D组术后6、12h血IL-6水平均明显高于A组、B组和C组,术后6、12、24h血IL-10水平均明显高于A组、B组和C组(P0.05);B组、C组术后6、12h血IL-6水平均明显低于A组,IL-10水平均明显高于A组(P0.05);C组恶心呕吐、嗜睡、头晕发生率明显高于A组、B组和D组(P0.05)。结论腹腔镜胆囊切除术患者术前15min静脉注射0.15mg/kg的羟考酮,可更加有效减轻拔管期应激反应,改善了术后疼痛和炎症反应,且未增加不良反应的发生和拔管时间、苏醒时间,值得临床重视。     

Administration of oxygen before tracheal extubation worsens gas exchange after general anesthesia in a pig model

Administration of 100% oxygen before tracheal extubation is common clinical practice. We determined the effect of this technique on postoperative gas exchange in a porcine model using the multiple inert gas elimination technique. After general anesthesia with mechanical ventilation for a period of 30 min (inspiratory fraction of oxygen of 0.3), anesthesia was discontinued, and the pigs were randomized to an inspiratory fraction of oxygen of 0.3 or 1.0 until they could be safely extubated. Thirty minutes after extubation while breathing air, blood flow to poorly ventilated units had significantly increased in pigs that had been administered 100% oxygen as compared with those receiving 30% oxygen (17% +/- 15% versus 7% +/- 5%; P = 0.009). We conclude that exposure to 100% oxygen before extubation may cause an undesirable alteration in gas exchange. IMPLICATIONS: Blood flow to lung units with a low V(A)/Q ratio was significantly larger in pigs that had been exposed to 100% oxygen before extubation as compared with those exposed to 30% oxygen before extubation.     

The use of dexmedetomidine during laryngoscopy, bronchoscopy, and tracheal extubation following tracheal reconstruction

We report the use of dexmedetomidine for laryngoscopy, rigid bronchoscopy, and tracheal extubation in the operating room in two children who had undergone tracheal reconstruction 1 week previously. Dexmedetomidine in combination with propofol provided appropriately deep anesthesia during these brief but stimulating procedures without cardiovascular or respiratory depression.     

三种不同剂量右美托咪定对全麻鼻内镜手术围拔管期应激反应的影响

目的 观察三种不同剂量右美托咪定对全麻鼻内镜手术患者围拔管期应激反应的影响,并探讨右美托咪定在围拔管期应用的最佳剂量.方法 100例择期行鼻内镜手术患者,ASA Ⅰ或Ⅱ级,随机均分为D1、D2、D3组和对照组(C组).手术结束前15 min D1、D2、D3组分别泵注右美托咪定0.3、0.6、0.9μg/kg,C组泵注等容量生理盐水,15 min内泵注完毕.记录给予右美托咪定前即刻(T1)、手术结束时(T2)、患者可唤醒时(T3)、拔管时(T4)、拔管后1 min(T5)、5 min(T6)、10 min(T7)的HR、MAP、RPP和心脏指数(CI);检测T1、T2、T4、T6时血浆中肾上腺素(E)、去甲肾上腺素(NE)、血糖(Glu)和皮质醇(Cor)的浓度.记录四组患者唤醒时间和拔管时间,并记录T4时拔管质量评分及T6时Ramsay镇静评分.结果 与T1时比较,T2～T6时D1组和C组MAP明显升高,HR明显增快,RPP、CI均明显增加(P＜0.05),T7时D2组,T6、T7时D3组MAP明显降低、HR明显减慢,RPP、CI明显减少(P＜0.05).与C组和D1组比较,T2～T7时D2组、D3组MAP明显降低,HR明显减慢,CI、RPP明显减少(P＜0.05).D3组苏醒时间和拔管时间均明显长于D1、D2组和C组(P＜0.05).与C组和D1组比较,D2组、D3组拔管质量评分明显降低,Ramsay镇静评分明显升高(P＜0.05).与D2组比较,D3组镇静评分明显升高(P＜0.05).四组患者拔管后未发生呼吸抑制不良反应.与T1时比较,T2、T4、T6时D1组、C组血浆中E、NE、Glu、Cor明显升高(P＜0.05).与C组比较,T2、T4、T6时D2组、D3组血浆中E、NE、Glu、Cor明显降低(P＜0.05).与D1组比较,T4、T6时D2组、D3组血浆中E、NE、Glu、Cor明显降低(P＜0.05).结论 对鼻内镜手术患者术毕前15 min给予0.6μg/kg右美托咪定可有效抑制全麻手术拔管期的应激反应,维持血流动力学的稳定,同时不延长患者苏醒时间和拔管时间.     

End-tidal sevoflurane concentration for tracheal extubation (MACEX) in adults: comparison with isoflurane

Sevoflurane has a non-pungent odour and provides smooth induction of anaesthesia. In contrast, isoflurane is irritating to the airway when used for induction, and this may also be evident during emergence from anaesthesia. We measured the end-tidal concentration of anaesthetic that prevented response to extubation in 50% of patients (MACEX) in adults receiving either sevoflurane or isoflurane. Airway complications during emergence from anaesthesia were also noted. We studied 51 adult patients, ASA 1, aged 36-59 yr. Patients received sevoflurane (n = 29) or isoflurane (n = 22) for elective intraocular surgery. The concentration at which extubation was attempted was determined by a modification of Dixon's up-and-down method. When tracheal extubation was accomplished without coughing and gross purposeful muscular movements within 1 min after extubation, it was considered a smooth tracheal extubation. Patients who developed breath-holding or laryngospasm immediately after tracheal extubation were regarded as not having been extubated smoothly. In addition, patients were observed for respiratory events during the remainder of the emergence period. MACEX values for sevoflurane and isoflurane were 1.07% and 0.83%, respectively. ED95 values of sevoflurane and isoflurane were 2.04% and 1.19%, respectively. In 12 patients in the isoflurane group, extubation was smooth but six patients had coughing episodes during the remainder of the emergence period. In contrast, one of 15 patients in the sevoflurane group in whom tracheal extubation was smooth coughed later (P = 0.035). Airway obstruction was frequent when tracheal extubation was performed at end-tidal concentrations exceeding 1 MACEX for each anaesthetic.      

艾司洛尔预防气管拔管时心血管反应的临床观察

目的 观察艾司洛尔对缓解气管拔管时期心血管反应的效果及安全性。方法 观察不同剂量艾司洛尔对全麻苏醒，气管拔管病人不同时间段的变化。结果 应用艾司洛尔2mg／kg组血压与心率恢复最快，与其他各组比较有显性差。拔管后瞬间三组心率(HR)均增快，血压(MAP)皆升高，D组持续了5分钟；El组持续了3分钟后恢复至基础水平；E2组拔管后瞬间MAP和HR均增加，但持续1分钟后MAP和HR皆恢复。结论 艾司洛尔可有效缓解气管拔管时期的心血管反应，且药效与剂量相关。     

Immediate postoperative extubation after minimally invasive direct coronary artery surgery (MIDCAB)

We were interested whether immediate postoperative extubation and early discharge of the intensive care unit (ICU) is safe in minimally invasive direct coronary artery surgery (MIDCAB) patients. Therefore we retrospectively analyzed the data from 217 patients undergoing MIDCAB from 2/99 to 4/02. Immediate postoperative extubation was possible in 182/217 (83.9%) with eight patients needing reintubation (11.5+/-3.3 h). Ventilation time of the remaining 35 patients was less than 24 h in 31 patients (8.8+/-5.3). Sixty-nine patients (31.8%) were directly transferred from the ICU. Immediate extubation after MIDCAB surgery is safe resulting in an effective use of resources.     

Effects of landiolol on the cardiovascular response during tracheal extubation

The objective of this study was to investigate the effect of landiolol on the cardiovascular responses to emergence from anesthesia and tracheal extubation. Fifty-nine patients without cardiovascular disorders who were scheduled for tympanoplasty were randomly allocated to receive a loading dose of landiolol at 0.125 mg x kg(-1) x min(-1) for 1 min, followed by an infusion at 0.01 mg x kg(-1) x min(-1) (group L1), 0.02 mg x kg(-1) x min(-1) (group L2), 0.03 mg x kg(-1) x min(-1) (group L3), or 0.04 mg x kg(-1) x min(-1) (group L4). At the end of surgery, sevoflurane and nitrous oxide were discontinued, and landiolol was started. The mean arterial pressure (MAP), heart rate (HR), and rate pressure product (RPP) in the four groups were compared before anesthesia induction, just after extubation, 5 min after extubation, 10 min after extubation, and at discharge from the operating room. Just after extubation compared with the baseline, the MAP increased significantly in all groups; the HR increased in groups L1 and L2; and the RPP increased in all groups, except for group L4. Continuous administration of landiolol, at 0.03 or 0.04 mg x kg(-1) x min(-1), may prevent the increases in HR and RPP, respectively, that occur at the emergence from anesthesia and tracheal extubation.     

The effect of increased intracranial pressure (ICP) on gastric motility

This study evaluates the effect of increased intracranial pressure (ICP) on gastric motility. Nine male cats (weight, 4.84 +/- 1.16 kg) were anesthetized with ketamine and underwent laparotomy for placement of bipolar (silver-silver chloride) electrodes on the serosal surface of the gastroesophageal junction (GEJ), antrum, and prepyloric areas of the stomach. At 1 week frontoparietal burr holes were performed with placement of an epidural Fogarty catheter. Migrating myoelectric complexes (MMCs) were evaluated at the GEJ, antrum, and prepyloric areas at varying levels of ICP (baseline and 20, 40, and 60 mm Hg) using balloon inflation. MMCs at the GEJ were triphasic with a period of 4 sec (+/- 1 sec) at baseline levels. At ICP levels above baseline, periodicity and waveforms at the GEJ became irregular. Waveforms became multiphasic with 1- to 2-sec periods and variable amplitudes. In the antral and prepyloric areas, duration and amplitude of the triphasic MMCs was unchanged from baseline. At 60 mm Hg ICP periodicity was significantly altered at both 1 and 2 weeks. MMCs returned to baseline levels with balloon deflation. The data indicate that elevated ICP (to 60 mm Hg) results in consistent and reproducible alterations of MMC periodicity, suggesting that such alterations may influence gastric motility.     

The effect of an infusion of esmolol on the incidence of myocardial ischaemia during tracheal extubation following coronary artery surgery

The aim of this randomised controlled study was to determine whether an esmolol infusion affected the incidence of ST segment changes during weaning from intermittent positive pressure ventilation and tracheal extubation after coronary artery surgery. Thirty-one patients received an infusion of esmolol 0-300 microg x kg(-1) x min(-1) and 37 patients comprised the control group. ST segment changes were monitored using a continuous ambulatory surveillance system. The electrocardiogram, direct arterial pressure and pulse oximetry were monitored continuously. The period of analysis was from 120 min before until 180 min after tracheal extubation. Three patients in the esmolol group developed myocardial ischaemia during the study period compared with 12 in the control group (p = 0.05). Heart rate increased with time during the study period (p = 0.002) in the control group but was unchanged in the esmolol group. Mean heart rate was significantly higher in the control group than in the esmolol group from 40 min before until 180 min after tracheal extubation. Seven patients in the esmolol group suffered adverse events related to the esmolol infusion. Although the use of esmolol reduced the incidence of myocardial ischaemia, the incidence of adverse effects makes it unsuitable prophylaxis for patients after coronary artery surgery.     

Increased Inspiratory Oxygen Fractions (FIO2) Using a Conventional Drug Delivery Nebuliser

Nebulised drugs are very useful in COPD exacerbations. The most frequently used propellant is compressed air, which is commonly administered together with nasal oxygen in those patients with respiratory failure. The purpose of this approach is to avoid the risks inherent in breathing high inspiratory oxygen fractions (FIO₂).AimTo analyze the actual FIO₂ obtained with such a common method under experimental conditions.MethodsVolunteers breathed using different patterns (quiet breathing, panting and deep breathing), through either the nose or the mouth, with oxygen flows of 0 vs. 4l/min. Then, they repeated quiet breathing and panting patterns, with nebulisation of saline propelled by compressed air (8l/min) and oxygen flows of 0, 2, 4, 6 and 8l/min. The F_IO₂ was simultaneously determined both in retronasal (RN) and retropharyngeal (RF) areas.ResultsDuring breathing without simultaneous nebulisation and oxygen flow of 4l/min, FIO₂ reached mean values of 0.42–.71 (RN) and 0.29–.38 (RF) for the three ventilatory patterns analyzed. With nebulisations during quiet breathing, mean FIO₂ values were 0.39 (RN) and 0.27 (RF) for 2l/min O₂ flow, 0.47 (RN), 0.34 (RF) for 4l/min, 0.58 (RN), 0.38 (RF) for 6l/min, and 0.68 (RN) and 0.50 (RF) for 8l/min. Similar results were obtained with the panting pattern.ConclusionThe FIO₂ obtained using the conventional nebulisation system (propulsion with compressed air and simultaneous nasal oxygen therapy) are relatively high, and therefore, might involve risks for COPD patients during exacerbations.     

非计划性拔管对兔气管黏膜形态结构的影响

目的探讨非计划性拔管(unplanned extubation,UE)对兔气管黏膜形态结构的影响及地塞米松对气管黏膜的保护作用。方法家兔20只,随机均分为四组,其中:正常组(G1组)未进行任何干预;对照组(G2组)正常插管并正常拔管;UE组(G3组)正常插管,并非计划性拔管;预处理组(G4组),建模前给予地塞米松0.5mg/kg,再正常插管,并非计划性拔管;使用ID 3.0mm导管,套囊压力25mm Hg,置留时间1h,拔管后4h取标本。HE染色观察比较各组气管黏膜压迫区和摩擦区的形态结构。结果与G1组比较,G2组压迫区和摩擦区0度损伤明显减少,Ⅰ度损伤明显增多(P0.01);与G1、G2组比较,G3组压迫区和摩擦区Ⅲ度、Ⅳ度损伤例数均明显增多,且以Ⅳ度增多更为显著,G4组压迫区和摩擦区Ⅲ度、Ⅳ度损伤例数均明显增多(P0.05或P0.01)。结论非计划性拔管会造成气管黏膜形态结构损伤,其致病机理包括套囊压迫、套囊摩擦以及致病菌感染,其中可能以套囊摩擦为主;且地塞米松对预防UE造成气管黏膜损伤效果不明显。