1、胃管和气道管理（Gastric tubes and airway management ）,钟泰迪浙江大学医学院附属邵逸夫医院,存在的问题(为什么讲课)？,饱胃病人常采用快诱导麻醉插管技术而这些容易误吸的病人术前常放置胃管是否诱导前必须，没有统一的临床指导规则也没有统一的意见是否诱导前将胃管放在原处，撤到食道，或排除,讲课内容,1.快诱导麻醉插管技术2.胃管放置的历史和现状3.环状软骨按压技术4.特殊高危误吸病人的一般处理,胃管发展史,17th,银管，喂食1790S, Hunter,鳗鱼皮，鲸骨，喂食1800S,中毒洗胃1921 Levin 单腔橡胶胃管作为胃肠减压和喂食1934, Mille
2、r and Abbott 采用了带套囊的二腔橡胶胃管,由于橡胶胃管插入困难，容易堵塞，一些病人发生过敏，1950s发展了塑料胃管 聚乙烯（polyethylene）, Polyvinyl and 硅树脂（silicone）聚氨酯（polyurethane） Salem-Sump 胃管，1960s ，双腔: a drainage lumen and a smaller secondary lumen that is open to the atmosphere to allow air to be drawn into the stomach and prevent the suction se
3、al effect on gastric mucosa during suctioning,目前有不同长度，不同官腔大小，不同用度和特殊用途的胃管胃管含有有利于定位的不透X线的线条14-20F用于成人，婴幼儿采用小型号32-36F大型胃管用于病理性肥胖腔镜下胃折叠手术,是否经鼻或经口插入决定于下列因素： 尽用于术中，还是整个围手术期。病人是清醒的还是无意识的是气管插管前放置胃管是否存在创伤后鼻咽部损伤 胃管的大小以及每一途径的相对风险也必须考虑,放置胃管的适应症,主要为诊断和治疗诊断方面：发现胃肠道出血测试消化道食物中毒 取得胃内培养标本测定胃内 pH 和胃容量监测胃肠引流情况,治疗方面包括:
4、 喂食灌药出血灌洗治疗低温清除口服药物过量,围手术期放置胃管通常目的,排除胃食道内容物减少误吸风险减轻术后呕吐预防和治疗术后胃扩张，麻痹性肠梗阻缓解肠梗阻症状避免腔镜手术时胃损伤改善通气,胃管放置的理念帮助喉罩的正确放置With the development of the laryngeal mask airway(LMA), the problem of malpositioning of the LMA cuff became recognized. Some newer types of LMAs incorporate a gastric port to separate the r
5、espiratory from the GI tract.Successful placement of a well-lubricated GT (up to 16 F)via the gastric port to the stomach accomplishes 2 functions:gastric access, and more importantly, facilitation of properLMA positioning.,从1930s 开始一直认为胃肠术后胃扩张导致肺误吸，切口裂开，吻合口漏，因此腹部手术病人常规置胃管进行胃肠减压。William W. Mayo once
6、 wrote “itis more important for a surgeon to carry a nasogastric tube than a stethoscope in his pocket”,一些研究支持腹部外科和其他术后常规留置胃管 一个多中心分析比较研究发现：无术后胃管病人腹胀和呕吐更常见。甚至心脏术后留置胃管比无胃管组呕吐发生率明显下降。近几年快速康复外科的发展提倡及早拔除所有管道！,放置胃管的并发症,咳嗽呕吐引起的血动学改变肺误吸打结：气管导管周围，会厌部，引起气道梗阻气管支气管出血低氧血症溃疡穿孔置入颅内和中耳损伤眼动脉,Pre-Sellick Era（环状软骨按压技
7、术之前）,在1961年环状软骨按压技术采用之前，避免误吸采用：神经阻滞，如硬麻，腰麻清醒插管全麻诱导时头高位40度,腰麻，硬麻缺点：,平面过高的腰麻，硬麻不能预防误吸的发生，如果过度镇静风险更大交感神经阻滞后胃肠蠕动加强平面过高时的通气不足，需要辅助呼吸,“清醒插管”,无论经鼻或经口都要有熟练的操作技术，良好表面麻醉，合适的镇静深度。否则操作困难，口鼻出血，血动学波动等并发症,关于头高位40度,1951年首次由Morton and Wylie与现在采用的快诱导插管不同点只是环状软骨按压麻醉和肌松情况下胃内压力18 cm H2O而头高位40度时成人咽喉部高于胃食道链接处19cm，因此理论上在此体
8、位下，哪怕胃内容物进入食道也不会到达咽喉部,另外，延迟手术通过大口径胃管排除胃内容麻醉诱导前催吐药的应用都是当时的临床常用方法,但由于催吐药的副作用，后来很快就放弃使用。,由于肠梗阻病人胃内排空后会持续充盈，因此麻醉诱导期间通常使用胃管减压诱导期留置胃管后确实消除了由呕吐返流引发的并发症因此急诊除分娩外常规术前放置胃管,用过带套囊胃管在胃食道链接处充气预防返流，但要做到密闭的充气压力而不损伤食道是不容易的,呕吐时，食道直径扩大，套囊移位，密闭效果变差。新型带套囊阻塞cardia 的采用，但没有流行.,环状软骨按压技术（The Cricoid Pressure Maneuver）,In 1961
9、, Sellick introduced CP “to control regurgitation of gastric or esophageal contents until intubation with a cuffed endotracheal tube was completed.”, Sellick当时通过充满造影剂的软乳胶膨胀导管，在颈5平面以10 cm H2O压力进行环状软骨按压，证明阻塞了食道腔。由于Sellick技术为高危误吸病人所设计，因此好多病人麻醉诱导前已经留置了胃管并且留置了胃管反而使食道上、下端括约肌收缩受影响，增加了返流的风险,Sellick强调“麻醉诱导前采
10、取所有合理的方法来排除胃和食道内容物，但如果认为留置了胃管就能保证胃内容能完全排空的想法是非常危险的。采用CP并且成熟后，Sellick修正了麻醉诱导前必须将胃管拔除的观点.,Post-Sellick Era,Sellicks 技术迅速成为快诱导插管技术的一部分在CP的新RSII 不仅适合于急诊、产科和危重医学也对有高危误吸的择期成人和儿科病人。CP的广泛接受是由于克服了头高位的缺点,第一,胃内压（ IGPs）高于20cm H2O 在胃扩张病人常见,头高位40 并不能完全预防胃食道内容到达第二,一当头高位期间胃内容到达咽喉处，误吸很可能发生。第三,低血容量病人头高位是不利的.,第四,由于小儿食
11、道短，头高位40时咽喉的高度没有达到克服胃食道连接处的胃内压,而且,由于小儿胃容量相对较小、哭闹期间过多空气的吸入，自发呼吸期间强烈的膈肌运动，因此小儿静息胃内压麻醉时远比成人高。,过去的几十年临床医师对CP的有效性和必要性提出了疑问。疑问主要是：(a) 数据和效果主要从死体上得到，因此缺乏科学依据。,(b) 食道并不是恰好位于CC的正后方，因此, 由CP产生的中线食道上端压迫并不可靠(c) CP 引起食道下端括约肌反射性松弛(d) 虽然应用了CP，但仍然有肺误吸的报道,(e) CP 触发恶心呕吐，甚至极少数食道破裂;(f) CP使气管插管，面罩通气和LMA放置困难,在Sellick原来的研究
12、中使用的是只要轻微按压就能阻塞的软乳胶管,但后来使用的是聚氨酯制成的硬胃管，很难用CP压力阻塞小儿和成人研究证实了CP对胃管周围的封闭是有效的.,这些发现建议麻醉诱导前不需要拔除胃管。对突然增加的胃内压可以开放胃管释放胃内容，而CP预防胃内容到达咽喉处,CP,In 1993, Vanner and Pryle 假设CC30 N 的力应用于CC10 cm2区域将产生200 mmHg 的压力 (30,000 N/m2 = 30 kPa).,但实际发现30 N的力，在胃内压超过40 mmHg时，食道内液体仍然有返流.可能的解释是对CC产生的压力并不是均匀分布的，有些区域的压力低于40 mmHg.,在
13、放置胃管病人，CP应用前后采用CT对CC区域进行扫描发现： 当CC结构压迫颈椎体一起时，食道腔的部分被压扁。轻轻侧旋CC结构腔道的其余部分压到椎体侧面的颈长肌上NGT 被挤到官腔压迫相对较小的腔的侧面.,这提示CP 压迫期间，NGT不但不影响CP对食道上端的压迫，实际反而能改善作用死体研究也证实放置胃管反而增加ICP的效果不管上述有效的证据，Sellick早期麻醉诱导前将胃管拔除的观点仍然受到一定的重视“胃管的存在影响食道括约肌收缩，是返流的基础”,特殊高危误吸病人的一般处理,高危误吸麻醉诱导前最大可能的吸氧使病人氧合达到最佳状态。大部分病人在充分给氧的情况下，3分钟左右深呼吸就可以达到最大氧
14、合。胃管留置病人可能使面罩和脸之间漏气氧合最少90%,可能困难插管，困难通气病人，氧合时间延长（10分钟）插管期间可通过鼻导管、口腔或环甲膜穿刺给氧纤支镜插管病人也可经面罩，鼻导管，口腔导管给氧,也可通过纤支镜通道给氧 对于气道狭窄病人，纤支镜通过狭窄部位会堵塞气道加重缺氧。低血容量病人适当补液昏迷病人用药根据实际情况,高血压病人必须采取适当技术缓解气管插管刺激血液动力学反应预测到困难气道的病人纤支镜技术优于RSII,颈椎不稳定病人纤支镜CP禁忌情况：咽喉壁脓肿食道上端异物咽喉部创伤颈椎损伤,-,谢谢!,Specific MeasuresEsophageal LesionsZenker div
15、erticulum(咽下部) is an outpouching of the mucosa,which develops in the weak area (Killian dehiscence裂开) between the thyropharyngeus and cricopharyngeus musclesCompressible swelling develops as the sac enlarges.Regurgitation of material from the pouch may occur during anesthetic induction, intubation,
16、or even after intubation due to seepage of fluid around the tracheal tube cuff duringsurgical manipulation.,Regurgitation of material from the pouch may occur during anesthetic induction, intubation, or even after intubation due to seepage of fluid around the tracheal tube cuff during surgical manip
17、ulation.Emptying of the pouch by the patient exerting external pressure before anesthetic induction is encouraged,The effectiveness of CP depends on the location of the body of the sac in relation to the CC.If the sac is small, the body of the pouch will be at the level of the CC; in such a case, CP
18、 will compress the body of the pouch, spilling the contents into the pharynx.If the sac is large, the neck of the pouch will be posterior to the CC, and CP will not empty the contents of the pouch into the pharynx,Review of the barium swallow is helpful in determining whether CP should be used if RS
19、II is chosen,Various anesthetic regimens including regional anesthesia, awake tracheal intubation, and RSII with CP or headup tilt have been used successfully for surgical repair of thediverticulum.Deep and superficial cervical plexus blockswithout complications have been reported in a series of 58
20、patients.,Regardless of the anesthetic choice, straining, gagging, or coughing should be avoided because they may cause external pressure to the pouch and provoke regurgitation.The tracheal tube cuff should be immediately inflated so as to prevent seepage of fluid around the cuff. Insertion of a GT
21、should be avoided because it can cause perforation of the diverticulum.If placement of a GT is necessary,caution must be exercised.,Achalasia（喷门失弛缓症） is an idiopathic disorder of the esophagus characterized by impaired relaxation of the LES and esophageal aperistalsis（蠕动停止） resulting in esophageal d
22、ilation,and retention of undigested food mixed with air.Food particles may remain in the dilated esophagus for many hours or days regardless of the duration of fasting.,This can result in regurgitation, aspiration, respiratory infections, upper respiratory obstruction, tracheal compression,and sudde
23、n obstruction of the tracheal tube during anesthesia.Treatments include endoscopic pneumatic dilation of the LES, surgical myomectomy, and botulinum toxin（肉毒素） injection.,Nitrates can cause transient relaxation of the LES and decompression of the esophageal dilation.Removal of material from the dila
24、ted esophagus by a wide-bore orogastric tube may lead to prompt resolution of symptoms,The insertion of a large-bore orogastric tube is advisable before proceeding with the anesthetic, even if it may not be completely effective in removing all food particles.Although we have used RSII in patients wi
25、th achalasia,awake intubation may be preferable in severe cases,Gastroesophageal Reflux,For pulmonary aspiration to occur, gastric contents must flow to the esophagus (GE reflux), the contents must reach the pharynx (esophagopharyngeal reflux), and the laryngeal reflexes must be obtunded.,Two lines
26、of defense prevent gastric contents from reaching the pharynx, the first at the GE junction, and the second at the upper esophageal sphincter (UES)Normally, the IGP is 10 to 15 cm H2Ohigher than the esophageal pressure, which is subjected to the negative intrathoracic pressure,If there were no mecha
27、nism to close the lumen between the 2 cavities, GE reflux would readily occur, especially if favored by gravity.Various “antireflux” mechanisms have been proposed, the most important is the tone of the LES, which maintains a pressure higher than the IGP,It is the difference between the LES pressure
28、and the IGP, “the barrier pressure,” thatdetermines whether regurgitation will occurAn increase in IGP or a decrease in LES tone will facilitate GE reflux,The IGP can increase secondary to an increase in intraabdominal pressure or when the normal capacity of the stomach (1.01.5 L in adults), which i
29、s determined by the complianceof the stomach and by the capacity of the abdominal cavity to accommodate the increased volume, is exceeded,The tone of the LES is influenced by neural, hormonal, pharmacologic, and pathologic factors.8487 An increase in IGP (orintraabdominal pressure) is generally acco
30、mpanied by an increase in LES pressure.This “adaptive” increase in LES tone occurs with increases in abdominal pressures up to 30cm H2O, and in normal individuals typically occurs with succinylcholine-induced fasciculations.,Because succinylcholine-induced increases in IGP are accompanied by disprop
31、ortionate increases in LES pressure, GE reflux normallydoes not occur.However, this phenomenon may be absent in some patients with GE reflux and gastric distension,In these situations, a further increase in IGP may promote GE reflux. In patients with symptoms of GE reflux and symptomatic hiatus hern
32、ia(食管裂孔疝), dysfunction of the LES results in alower barrier pressure, allowing flow of gastric contents into the esophagus,Pharmacologic approaches to promotegastric emptying, increase barrier pressure, and decrease or neutralize gastric acidity have gained popularity in the preanesthetic management
33、 of patients with GE reflux.The reader is referred to other sources for more information on this subject.The value of routine use of GTs in patients withGE reflux has not been addressed in the literature.,Certain anesthetic complications or maneuvers can induce GE or esophagopharyngeal reflux. Airwa
34、y obstruction may cause GE reflux by increasing the pleuroperitoneal pressure difference during strong respiratory effortsand by increasing the IGP due to overaction of the diaphragm,Positive pressure ventilation (in excess of 20cm H2O) before tracheal intubation may lead to intermittent opening of
35、the UES and LES, resulting in gastric insufflation and a subsequent increase in IGPNormally, the UES tone creates a sphincteric pressure of about 38 mmHg in awake subjects,This tone is markedly decreased by muscle relaxants and induction drugs, with the exception of ketamine.Relaxation of the UES or
36、 its mechanical stretching during intubation can facilitate the flow of esophageal contents, if present, to the pharynx.It has been suggested that CP substitutes for the loss of the UES tone, which accompanies anesthetic induction and muscle relaxation.,Gastric Distension,GI obstruction can be mecha
37、nical as in pyloric stenosis or functional as in ileus caused by peritonitis or trauma.Regardless of the cause, GI obstruction ultimately leads to gastric distension, which can cause an increased IGP, GE reflux, and vomiting.,The decision to insert an NGTbefore anesthetic induction depends on the de
38、gree of distension.Assessment of the degree of gastric distension and bowel obstruction can be made from the clinical and imaging findings.,Bedside ultrasonographic assessment of the gastric antrum and body can provide quantitative information about the volume of the gastric contents as well as qual
39、itative information regarding its nature (gas,fluid, or solid).An estimated volume in excess of 200 to300 mL in adults suggests the presence of severe distension and serves as an indication for placement of an NGT before anesthetic induction.,Investigators have argued about whether gastric contents
40、can be removed completely with a GT. Some investigators reported that the volume removed via a GT underestimates the true volume of gastric contents.,Others demonstrated that this method is a very reliable estimate of the total volume of gastric contents.Obviously, many factors influence the success
41、 of blind gastric emptying.These include size, type, and patency of the GT and its correct placement,position of the patient, use of external abdominal pressure, and consistency of contents.,The use of a multiorifice,vented, large (18 F) GT is more effective than the use of anonvented GT. Multiple d
42、istal openings ensure that nearlyall gastric pouches are drained. Even if gastric suctioning does not guarantee complete emptying, it reduces the IGP,and the residual volume becomes clinically insignificant as an aspiration risk,Many measures have been proposed to facilitate proper GT placement, the
43、 application of which depends on whether the patient is awake or anesthetized and whether the GTis inserted nasally or orally.,These measures include selecting the proper size; generous lubrication; encouragingthe awake patient to swallow during insertion; neck flexion or anterior displacement of th
44、e thyroid cartilage; advancing the GT along the posterior pharyngeal wall using fingersplaced in the pharynx, stiffening the GT by chilling, using a stylet or a Fogarty catheter; guiding the GT through an esophageally placed uncuffed ETT; and advancing the GTunder direct-vision laryngoscopy with or
45、without the aid of a Magill forceps,Confirmation of proper GT placement isessential.Radiologic verification is consideredthe “gold standard”; however, this may not be feasible.Although not as reliable, other approaches have been used.,These include visual inspection and pH testing of aspirate;epigas
46、tric/left upper quadrant auscultation for a gurgling noise during air insufflation; manual palpation by the surgeon (intraoperatively); confirmation by direct laryngoscopy or fiberoptic bronchoscopy; and absence of carbon dioxide by capnograph (to exclude tracheal placement).,Detection of carbon dioxide implies the presence of the unobstructed GT in the airway.In infants and young children, a GT can often be visually observed “rippling” alongthe inside of the left abdominal wall during insertion,-,谢谢!,
