石磊-肥胖门诊麻醉

The Adult Patient With Morbid Obesity and/or Obstructive Sleep Apnea For Ambulatory Surgery,Girish P. Joshi, MB BS, MD, FFARCSI协和规培：石磊,病态肥胖及阻塞性睡眠呼吸暂停病人的门诊手术麻醉（一）,Introduction,Morbidly obese（病态肥胖） have an increased risk of Co-morbidities(并存病，Table 1), and therefore pose considerable challenges to the anesthesiologist (Table 2). One of the major co-morbidities associated with obesity includes obstructive sleep apnea (阻塞性睡眠呼吸暂停，OSA), reported in 60-70% of morbidly obese.,简介,Introduction,Table 1: Co-morbidities（并存病） Associated With Obesity（肥胖）Respiratory（呼吸系统）: Restrictive pulmonary disease（限制性肺疾病）, obstructive sleep apnea（阻塞性睡眠呼吸暂停）, asthma（哮喘）, Pulmonary hypertension（肺动脉高压）Cardiac（心血管）: Systemic hypertension（系统性高血压）, coronary artery disease（冠状动脉心脏病）, dysrhythmias（心律失常）, Cardiomyopathy（心肌病）, CHF（慢性心衰）Neurologic（神经系统）: Stroke（中风）Renal（泌尿系统）: Renal dysfunction（肾功能不全）Metabolic（内分泌）: Metabolic syndrome（代谢症候群）, type 2 diabetes mellitus（2型糖尿病）, hypothyroidism（甲低）,Introduction,Table 2: Challenges in the patients with morbid obesity(病态肥胖) and/or OSA （阻塞性呼吸暂停综合征）undergoing ambulatory surgery（门诊手术）.Intra-operative（手术中）: Difficult/failed mask ventilation（面罩通气） and/or tracheal intubation（气管插管）Difficulty in ventilation and/or maintaining adequate oxygen saturation（维持足够氧饱和度）Diffculty in positioningExacerbation of cardiac co-morbidities（心血管并存病加重）: hypertension（高血压）, arrhythmias（心律失常）,myocardial ischemia（心肌缺血）and infarction（梗塞）, pulmonary hypertension（肺动脉高压）, heart failure（心衰）,Introduction,Immediate postoperative（术后即刻）: Delayed extubation（拔管延迟）Obstruction and/or desaturation after extubation（拔管后梗阻）Post-obstructive pulmonary edema（梗阻后肺水肿）Need for tracheal reintubation（再插管）Exacerbation of cardiac comorbidities（心血管并存病加重）Cerebrovascular disorders (e.g., stroke)（脑血管疾病）Postoperative delirium（术后谵妄）Prolonged PACU stay（恢复室逗留时间延长）Delayed discharge home（住院时间延长）,Introduction,Post-discharge（出院后）: Readmission after discharge （出院后再入院）Hypoxic brain death and death（缺氧性脑死亡和死亡）,Selection of Adult Patients Morbidly Obesity and/or OSA For Ambulatory Surgery (病态肥胖及阻塞性睡眠呼吸暂停病人的选择),A recent systematic review revealed that BMI alone might not influence perioperative complications or unplanned admissions （BMI指数并不单独影响围术期并发症). Therefore, BMI should not be considered the sole patient selection criterion for ambulatory surgery(BMI不应作为独立的选择标准). Overall, the patient selection for ambulatory surgery should depend upon the severity of co-morbidities, the surgical procedure, and the anesthetic technique（取决于并存病严重程度、手术过程、麻醉技术）.,Selection of Adult Patients Morbidly Obesity and/or OSA For Ambulatory Surgery,Overall, patients with inadequately treated co-morbid conditions（未经充分治疗的并存病状况）are not suitable for ambulatory surgery（不适合门诊手术）. Also, it is imperative that all surgical patients are evaluated for presence of OSA, preoperatively（术前对OSA评估）. Patients with known diagnosis of moderate-to-severe OSA（确诊中重度的OSA） and optimized comorbid conditions（并存病处在最佳状况）can be considered for ambulatory surgery, if they are able to use the CPAP device in the postoperative period （术后使用持续正压通气）.,Selection of Adult Patients Morbidly Obesity and/or OSA For Ambulatory Surgery,Patients with presumed diagnosis of OSA and optimized comorbid conditions（疑似OSA和最佳并存病状况） can be considered for ambulatory surgery, if postoperative pain can be managed predominantly with non-opioid Analgesic Techniques（由非阿片类术后镇痛）. In addition, the ability of the facility to manage these patients should also be taken into consideration （同时考虑应用设备的能力）.,Preoperative Considerations,Morbidly obese patients (BMI 40 kg/m2) suffer from numerous chronic medical conditions (许多慢性医疗症状，Table 1). Because OSA is undiagnosed in an estimated 60-70% of patients（大约60-70%未确诊）, screening for OSA should be part of routine preoperative evaluation（筛查OSA应作为常规术前评估）. The STOP-BANG screening tool is a user-friendly questionnaire（STOP-BANG是一个病人易掌握的调查问卷） that could be included in routine preoperative evaluation to identify unrecognized OSA (Table 3). Two recent studies have validated（证实） the STOP-BANG questionnaire and found that a higher STOP-BANG score identified patients with high probability of moderate/severe OSA（高分提示中重度OSA的可能）,术前注意事项,Preoperative Considerations,Table 3: STOP-BANG Scoring SystemS = Snoring（打鼾）. Do you snore loudly (louder than talking or loud enough to be heard through closed doors)?T = Tiredness（疲劳）. Do you often feel tired, fatigued, or sleepy during daytime（白天欲睡）?O = Observed Apnea（观察到的呼吸暂停）. Has anyone observed you stop breathing during your sleep?P = Pressure（高血压）. Do you or are you being treated for high blood pressure?B = BMI 35 kg/m2A = Age 50 yearsN = Neck circumference 40 cmG = Male GenderHigh risk of OSA: 3 or more questions answered yesModerate-to-severe OSA: 6 or more questions answered yes,Preoperative Testing,The American college of Cardiology (ACC) and American Heart Association (AHA) recommended that ECG be obtained in patients with at least one risk factor for CHD and/or poor exercise tolerance（有至少一个冠心病危险因素或运动耐量差的病人）. ECG signs of right ventricular hypertrophy including right-axis deviation and right bundle-branch block would suggest pulmonary Hypertension（右心室肥大提示肺动脉高压）, while a left bundle-branch block may suggest occult CHD（左束支阻滞提示隐匿冠心病）. In addition, chest X-ray should be obtained on all morbidly obese patients as it may suggest undiagnosed heart failure, cardiac chamber enlargement, or abnormal pulmonary vascularity suggestive of pulmonary hypertension （提示未诊断的心衰、心室增大或异常的肺血管分布）, which warrants further cardiovascular Investigation（作为其他心血管检查的依据）.,术前检查,Preoperative Testing,Although obesity can influence pulmonary function，pulmonary function tests (e.g., spirometry), are of no added benefit unless COPD is suspected（虽然肥胖可能影响肺功能，但肺功能检查并不是必须，除非怀疑有COPD ）. If OSA is suspected during preoperative evaluation, one could proceed with a presumptive diagnosis of severe OSA or obtain a sleep study（如果怀疑有OSA，医生可以进一步做出重度OSA的诊断或者进行睡眠实验）.,Preoperative Medications,Obese patients may be on multiple medications including prescription and non-prescription (i.e., over-the counter or herbal diet drugs) （非处方药或者中草药）that might have detrimental cardiopulmonary effects as well as adversely interact with anesthetic drugs（对心肺有害或影响麻醉药作用）. Patients should be asked to continue their preoperative medications until the day of surgery（嘱咐病人用药直至手术当天）, Because morbid obesity is one of the major risk factors for the development of pulmonary embolism（病态肥胖是肺栓塞发展的主要危险因素之一）, prophylaxis for deep vein thrombosis（预防深静脉血栓）, low dose heparin in,术前用药,Preoperative Medications,combination with intermittent pneumatic compression, are recommend（建议小剂量肝素，同时间歇气压疗法）Preoperative prophylaxis against acid aspiration (e.g., H2-receptor antagonists and proton pump inhibitors)（返流误吸措施包括H2受体阻滞剂和质子泵抑制剂） is commonly used. However, their routine use is questioned, as the risk of regurgitation of 、gastric contents for the morbidly obese and the non-obese appears to be similar（是否常规使用值得商榷，因为病态肥胖病人返流的风险与常人无异）.,Intraoperative Considerations,Although the surgical procedure and the need for postoperative opioids, rather than the choice of anesthetic technique appear to be more important determinants of perioperative complications in the morbidly obeseparticularly those with OSA（病态肥胖，特别是合并OSA的病人中，相对麻醉选择的技术，手术过程和术后阿片类的需要似乎更应该是围术期并发症的决定因素）, local or regional anesthesia should be preferred（即使如此，也应该选择局部区域阻滞麻醉应）. Local/regional anesthesia obviates the need for airway manipulation as well as avoids hypnotic-sedatives, opioids, and muscle relaxants（局部区域阻滞避免了气道管理、镇静催眠和阿片类、肌松药的使用）. In addition, these techniques provide postoperative analgesia and reduce postoperative opioid requirements（同时也提供了术后镇痛、减少阿片类的使用量）.,术中注意事项,Sedation and Analgesia in the Obese and OSA Patients,Patients with OSA are more sensitive to sedative-hypnotics and opioids（病人对镇静催眠和阿片类更敏感）, which cause dose-dependent upperairway collapse, respiration depression, and reduced respiratory responses to hypoxia and hypercapnia（导致剂量依量性呼吸道塌陷，呼吸抑制、减少呼吸系统对缺氧和二氧化碳潴留的反应）. Of note, during sedation OSA may develop in previously unrecognized patients（镇静状态下，之前未发现的病人可能出现新发展的OSA）. Therefore, monitoring should include continuous capnography as it allows detection of upper airway obstruction much prior to oxygen desaturation（必须持续监测二氧化碳因为相对氧饱和度，它能更早提示上呼吸道梗阻）.,Sedation and Analgesia in the Obese and OSA Patients,Midazolam and propofol have a similar propensity for upper airway obstruction at similar levels of sedation（咪达唑仑和丙泊酚有类似的引起上呼吸道梗阻的倾向）. Dexmedetomidine, a highly selective alpha-2 adrenergic agonist with sedative, amnestic, analgesic, and sympatholytic properties with norespiratory depression（右美托咪定，同时具有镇静、遗忘、镇痛和抗交感，但无呼吸抑制）, can be used to provide sedation/analgesia. In addition, it reduces salivary secretions through sympatholytic and vagomimetic effects（除此之外，通过抗交感和类迷走作用能减少腺体分泌）.,The Adult Patient With Morbid Obesity and/or Obstructive Sleep Apnea For Ambulatory Surgery,Girish P. Joshi, MB BS, MD, FFARCSI 协和规培：石磊,病态肥胖及阻塞性睡眠呼吸暂停病人的门诊手术麻醉（二）,General Anesthesia,The optimal general anesthetic technique would allow rapid and clear-headed recovery including early return of the patients protective airway reflexes（最佳的全麻技术可以让病人快速恢复清醒，包括呼吸道的保护反射）, which would allow maintenance of a patent airway（维持通畅呼吸道）. In addition, early recovery should reduce postoperative cardiac complications due to residual anesthetic effects（及早恢复清醒可减少残余麻醉效果导致的术后心血管并发症）.,Airway Management,Because BMI alone is not a predictor of difficult intubation（由于BMI并不能单独作为困难插管的指标）, awake tracheal intubation may not always be necessary（清醒插管不总是必须的）. Nevertheless, OSA has been reported to be a predictor of difficult airway （OSA是作为困难气道的指标之一） Predictors of difficult tracheal intubation include high Mallampati score (III or IV), neck circumference（颈围） 40 cm, limited mandibular protrusion（短下颌）, and severe OSA (AHI 40).,Airway Management,The availability of videolaryngoscopes has increased the success of tracheal intubation（可视喉镜可以提高插管的成功率）. A recent study in morbidly obese reported that the awake videolaryngoscopy after topical anesthesia can be considered as an alternate to awake fiberoptic tracheal intubation （局部麻醉下后清醒可视喉镜插管可以作为清醒纤支镜插管的替代品之一）,Induction of General Anesthesia,Recent studies, in morbidly obese patients, have shown that the barrier pressure (lower esophageal pressure gastric pressure) remains positive throughout induction of anesthesia屏障压力（食道下段压力-胃内压）在麻醉诱导的过程中仍然维持作用）. This suggests that the risk of gastric regurgitation in the morbidly obese is similar to that in the non-obese patients（提示病态肥胖病人的返流风险并没有比其他病人更高）. Most anesthesia drugs including intravenous anesthetic drugs and opioids should be dosed according to lean body weight (not actual body weight)（包括静脉麻醉药和阿片类在内的大多数麻醉药应该依据去脂体重计算）, except for neuromuscular blocking drugs, which should be dosed according ideal body weight（除了依据理想体重计算的肌松药）.,全麻诱导,Maintenance of General Anesthesia,Several studies have reported that in the morbidly obese, Compared with sevoflurane, desflurane allows earlier ability to swallow water withoutcoughing or drooling（和七氟醚相比，地氟醚允许病人出现更早的吞咽动作）, suggesting an earlier return of protective airway reflexes（提示病人更早恢复气道保护反射）. A recent study used anesthesia information management system as well as metaanalysis of 29 randomized controlled trials comparing desfluraneand sevoflurane to determine the time from end of surgery to tracheal extubation （对比了手术结束到拔管的时间）. They found that compared with sevoflurane, desflurane reduced the mean extubation time by 25%（地氟醚的平均拔管时间少了25%）,全麻维持,Mechanical Ventilation,Obesity is associated with changes in pulmonary function （肥胖常影响肺功能）(e.g., reduction in lung volumes, increase in peak inspiratory pressures, and decrease in pulmonary compliance，肺容量降低、吸气压峰值增高、肺顺应性降低). Lung protective ventilation strategies in the obese would include the use of pressure-controlled ventilation with low tidal volumes (8-10 ml/kg IBW) （较低潮气量的压控通气）and PEEP of 5-10 cmH2O 34.,Mechanical Ventilation,It is important to avoid hyperventilation and hypocapnia（避免通气过度和低碳酸血症）, as this may result in metabolic alkalosis （代谢性碱中毒）and lead to postoperative hypoventilation（术后通气不足）. Mild hypercapnia（轻微的高碳酸血症） (i.e., ETCO2 of 40 mmHg) can improve tissue oxygenation through improved tissue perfusion resulting from increased cardiac output and vasodilatation as well as increased oxygen off-loading from the shift of the oxyhemoglobin dissociation curve to the right（可以提高心排出量和舒张血管，同时使氧合血红蛋白曲线右移，来提高组织氧供）.,Nausea and Vomiting Prophylaxis,Patients undergoing ambulatory surgery are at a higher risk of PONV and should receive prophylactic multimodal antiemetic therapy（预防性多方式止吐治疗） (e.g., combinations of 5-HT3-receptor antagonists, droperidol, and dexamethasone，5-HT3受体抑制剂、氟哌利多、地塞米松). Although it is recommended that the number of antiemetics be based on the patients level of risk as determined by risk factor assessment, double or triple antiemetic prophylaxis is optimal for this patient population（虽然建议止吐药的种类由病人的风险因素水平决定，但二联或三联止吐预防通常最佳）.,预防恶心呕吐,Intraoperative Fluid Management,Adequate preoperative hydration (i.e., encourage patients to consume water until 2 h preoperatively，术前足够补液，鼓励患者术前喝水直到术前2小时) and higher intraoperative fluid administration (20-40 ml/kg) have been reported to reduce postural hypotension, postoperative dizziness, drowsiness, nausea, and fatigue（较好的术中液体管理可以减少体位性低血压、术后眩晕、呕吐和疲劳）.In addition, because the morbidly obese are at a high risk ofRhabdomyolysis（肥胖病人是横纹肌溶解高危病人）, administration of higher fluid volumes may reduce the potential for myoglobinuric acute renalfailure associated with rhabdomyolysis（高液体容量可以减轻潜在的肌红蛋白引起的急性肾衰）.,术中液体管理,Emergence From Anesthesia,One of the major concerns in obese patients, particularly those with OSA, is the risk of airway obstruction after tracheal extubation（肥胖病人、特别是合并OSA，最大的担忧是拔管后气道梗阻）. Thus, prior to tracheal extubation the patient must be fully awake, alert, and follow verbal commands (i.e., deep extubation is not advisable)（拔管前，病人应该完全清醒、警觉、能受口头指挥，另外不建议深麻醉下拔管）. Importantly, coughing and reflex movements of the hand towardsthe tracheal tube should not be confused as purposeful movements（很重要的，呛咳和手指向导管的运动，不能当做是患者有意识的运动）.,Emergence From Anesthesia,Extubation should be performed in a semi-upright (25-30 head-up) position, when possible（可能的话，拔管应该在半卧位下）. Also, use of a nasal airway, placed before tracheal extubation,may avoid postextubation airway obstruction （拔管前使用鼻咽通气道，可以预防拔管后气道梗阻）. A recent study suggests that a nasal airway is more effective than acombination of oral and nasal airway（鼻咽通气道比同时使用鼻咽和口咽通气道有效）. A recent study reported that CPAP instituted immediately after tracheal extubation is superior in maintaining lung function at 24 h after laparoscopic bariatric surgery than CPAP initiated later in the recovery room（一个研究显示腹腔镜治疗肥胖症的病人中，拔管后立即使用CPAP在维持肺功能方面，优于晚到恢复室再使用CPAP）.,Postoperative Considerations,Potential postoperative complications include airway obstruction, respiratory failure, need for reintubation, life threatening hypoxia as well as systemic hypertension, ischemia, and cardiac arrhythmia（潜在的术后并发症包括气道梗阻、呼吸衰竭、再插管的需求、低氧血症、高血压、组织缺血即心律失常）. Once in the PACU, patients should be maintained in a semi-upright (25-30 head-up) position, if possible（如果可能，病人进入恢复室应立即给予半头高位）.,术后注意事项,Postoperative CPAP/BiPAP,Although supplemental oxygen is beneficial for most patients, it should be administered with caution as it may reduce hypoxic respiratory drive andincrease the incidence and duration of apneic episodes（虽然补充氧气对大部分病人有益，但也可能降低呼吸系统的低氧驱动功能和对呼吸暂停的耐受）. Because obese patients might have unrecognized OSA,recurrent hypoxemia may be better treated with CPAP or bi-level positive airway pressure (BiPAP) along with oxygen rather than oxygen alone（如果反复出现低氧血症，病人最好使用CPAP或BiPAP，而不是单独吸氧）.,Post-PACU Discharge Care,Prior to discharge from the PACU the oxygen saturation on room air should return to baseline （出恢复室前氧饱和度回到基本水平）and the Patient should not become hypoxic or develop airway obstruction when left undisturbed in the recovery area（未打扰情况下不应该有低氧血症或气道梗阻）. It has been suggested that most significant postoperative complications in OSA patients usually occur within 2 hours after Surgery（大多数的OSA病人并发症发生在术后2小时内）. Therefore, it may be worthwhile to observe these patients in the recovery room for at least 2 h（因此建议这类病人在恢复室至少停留2小时）.,Post-PACU Discharge Care,The ASA-OSA Practice Guidelines suggest that OSA p