Awake tracheal intubation through the laryngeal mask in neonates with upper airway obstruction

Neonates with Pierre Robin or Treacher-Collins syndrome are at risk of upper airway obstruction and may require surgical fixation of the tongue to the mandible. Such neonates are at high risk of hypoxia during induction of anesthesia and thus awake fiberoptic intubation would be required. We experienced neonates in whom awake fiberoptic intubation could not be carried out, because of severe hypoxia. Awake insertion of the laryngeal mask solved this problem. A 1-month-old neonate with Pierre Robin syndrome and another with Treacher-Collins syndrome were scheduled for surgical fixation of the tongue to the mandible, for constant upper airway obstruction. In both patients, awake fiberoptic intubation was attempted but abandoned, because SpO(2) rapidly decreased during the attempts. Awake insertion of the laryngeal mask relieved upper airway obstruction and facilitated oxygenation. Fiberoptic intubation through the laryngeal mask was easily achieved. Anesthesia was then induced. No hypoxia occurred after insertion of the laryngeal mask. In a further two neonates with Treacher-Collins syndrome and in one neonate with Pierre Robin syndrome, awake fiberoptic intubation through the laryngeal mask was also successful. We believe that in neonates with predicted difficult intubation, who are at risk of upper airway obstruction and awake fiberoptic intubation could aggregate hypoxia, awake insertion of the laryngeal mask can be useful in facilitating oxygenation (by relieving upper airway obstruction) and in facilitating fiberoptic intubation.     

Bronchial responsiveness to inhaled histamine and isoprenaline in patients with airway obstruction

In order to examine the hypothesis that bronchial reactivity to non-specific constrictor stimuli is influenced by the resting tone of the bronchial smooth muscle, the airway responses to inhaled histamine solution and inhaled isoprenaline were measured in 19 patients with airway obstruction. There was a significant positive correlation between the size of the constrictor response to histamine and the dilator response to isoprenaline (r = +0.83; p less than 0.01) as measured by changes in specific airway conductance. Patients with asthma showed greater bronchial reactivity to both histamine and isoprenaline than those with chronic bronchitis, although some patients had changes intermediate between the two extremes.     

Comparison of cardiorespiratory effects of terbutaline and salbutamol aerosols in patients with reversible airways obstruction

Harris, L. (1973).Thorax, 28, 592-595. Comparison of cardiorespiratory effects of terbutaline and salbutamol aerosols in patients with reversible airways obstruction. The effects of pressurized aerosol administration of terbutaline were compared with those of salbutamol in 14 patients with at least 20% reversibility of airways obstruction. The two drugs were found to be equipotent bronchodilators in the dosage used. Salbutamol was found to produce significant increases in minute ventilation, physiological dead space/tidal volume ratio, and ventilatory equivalent for oxygen, with significant falls in arterial oxygen tension and heart rate. Terbutaline did not induce significant changes in any of these variables. These results suggest that terbutaline is less likely than salbutamol to have an adverse effect upon ventilation-perfusion relationships.     

The incidence of bacteraemia associated with tracheal intubation

Expert committees on bacterial endocarditis prophylaxis have provided differing opinions on whether tracheal intubation is an 'at-risk' manipulation. We studied the incidence of bacteraemia after orotracheal and nasotracheal intubation. The study group comprised 110 patients who underwent surgery under general anaesthesia. Venous blood samples were collected from each patient at baseline and 30 s after intubation. Samples were processed with conventional microbiological techniques. Bacteraemia after tracheal intubation was detected in 13 patients (11.8%); six after orotracheal intubation and seven after nasotracheal intubation. Staphylococci and streptococci were the most commonly isolated bacterial species. Seven isolates (54%) were resistant to oxacillin. The incidence of bacteraemia was similar after orotracheal (12.0%) and nasotracheal intubation (11.7%). The recommendation for bacterial endocarditis prophylaxis with flucloxacillin when performing nasotracheal intubation, as put forward by the British Society for Antimicrobial Chemotherapy, needs further consideration.     

Emergency gum elastic bougie-assisted tracheal intubation in four patients with upper airway distortion

PURPOSE: The gum elastic bougie (GEB) has been in use for a long time and allows tracheal intubation in most cases of difficult direct laryngoscopy. Use of the GEB when anatomical landmarks of the upper airway are not recognizable has not been reported. We describe our experience of airway management with the GEB in cases of severe upper airway distortion. CLINICAL FEATURES: Four patients with severe respiratory distress caused by upper airway distortion secondary to various non-malignant causes were managed with the GEB. For these four patients, a rapid sequence induction of anesthesia was performed with a surgeon present during the procedure. The GEB was used as the initial intubating technique in all cases and allowed a rapid and successful tracheal intubation in spite of non-recognizable anatomical structures. The distal hold-up feeling after GEB insertion confirmed, in all cases, the correct intratracheal position of the GEB. CONCLUSION: The GEB can be a valuable tool in cases of difficult airway management caused by upper airway distortion. The lack of visualization of normal pharyngeal structures did not prevent the successful insertion of the GEB in the trachea in the four patients reported.     

右美托咪定联合插管型喉罩在困难气道插管中的应用

目的 评价右美托咪定诱导联合插管型喉罩或纤维支气管镜(FOB)在清醒保留呼吸情况下气管插管的效果.方法 择期手术全麻患者96例,ASAⅡ或Ⅲ级,术前气道评估Mallampati分级≥Ⅲ级,Cormack-Lehane分级≥Ⅲ级.随机均分为四组:A组静注右美托咪定1μg/kg(10min)+芬太尼2 μg/kg联合插管型喉罩插管;B组静注咪达唑仑0.03 mg/kg+芬太尼2μg/kg联合插管型喉罩插管;C组静注右美托咪定1 μg/kg(10min)+芬太尼2μg/kg经鼻FOB插管;D组静注咪达唑仑0.03mg/kg+芬太尼2μg/kg经鼻FOB插管.记录麻醉前(T0)、静脉推注右美托咪定或咪达唑仑完毕即刻(T1)、静脉推注芬太尼后(T2)、置入插管型喉罩或FOB到达会厌即刻(T3)、插入气管导管时(T4)、插入气管导管后1 min(T5)、插入气管导管后给予肌松药后3min(T6)时MAP、HR、SpO2、BIS,并记录插管成功率、心动过速、高血压、有无躁动、呛咳等插管反应,记录插管前心动过缓使用阿托品和插管后的心动过速使用艾司洛尔情况,术后随访患者对插管过程是否耐受.结果 与T0时比较,T2、T3时A、C组HR明显减慢,T3～T5时B、D组HR明显增快,T3～T5时B、D组和T4、T5时C组MAP明显升高(P＜0.05).诱导插管前阿托品使用率A、C组明显高于B、D组;插管后艾司洛尔使用率A、C组明显低于B、D组(P＜0.05);术后躁动发生率A、B、C组均明显低于D组(P＜0.05);对麻醉中插管的耐受、下次是否愿意使用同样的麻醉方法A组均明显高于B、C、D组(P＜0.05).结论 右美托咪定联合插管型喉罩在困难气道保留呼吸插管安全有效,而且可以减少心动过速、高血压及心肌缺血发生率,增强对气管插管的耐受.     

困难气道患者上气道三维CT图像的改变

目的 评价困难气道患者上气道三维CT图像的改变,为困难气道的预测提供客观依据.方法 择期全麻手术男性患者17例,年龄25～60岁,身高165～185 cm,体重55～110kg,体重指数19～33 ks/m2,ASA Ⅰ或Ⅱ级.术前行Mallampati评分、Willson综合评分,并进行上气道三维CT扫描,分别测量伸舌前和伸舌时口咽腔内空腔容积(分别为Va1和Va2)、舌体体积(分别为Vt1和Vt2)、硬腭后缘所在冠状位口咽腔内空腔截面积(分别为Aa1和Aa2)和舌体截面积(分别为At1和At2),于正中矢状位测量上门齿与舌根部连线与水平线的夹角即直接喉镜视角,测量下颌骨平面与舌骨平面的垂直距离(MHD).患者均行清醒盲探气管插管,麻醉诱导后采用直接喉镜暴露,根据Cormack-Lehane 分级分为2组:非困难气道组(NDI组)Cormack-Lehane分级为Ⅰ或Ⅱ级;困难气道组(DI组)Cormack-Lehane分级为Ⅲ或Ⅳ级.结果 NDI组8例,DI组9例.与NDI组比较,DI组伸舌前各指标比较差异无统计学意义(P>0.05),Va2、Va1-Va2、Aa2、Aa1一Aa2、At1-At1减小,MHD延长,Va1/Vt1-Va2/Vt2增大(P<0.05或0.01);与Va1或Aa1比较,DI组Va2、Aa2减小(P<0.05).结论 困难气道患者上气道三维CT图像的改变主要表现为伸舌时口咽腔内空腔容积和截面积减小,伸舌前与伸舌时空腔容积,舌体体积比的差值增大,MHD延长.     

Topical anaesthesia of the airway using Trachlight and MADgic atomizer in patients with predicted difficult tracheal intubation

Editor—Although awake intubation is the technique mostcommonly chosen in cases with a difficult airway, gag, cough,and laryngospasm in response to intubation may be troublesome.¹The MADgic^® atomizer (Wolfe Tory Medical Inc., Salt LakeCity, UT, USA) is a new device for spraying topical anaestheticsin the laryngotracheal region, which provides atomized topicalsolution directly to the mucosa of the airway. The applicatorportion can also be adapted to an individual patient's anatomy.²However, use of MADgic^® atomizer to spray local anaestheticsin an airway requires direct laryngoscopy which may not onlyresult in oropharyngeal     

困难气道患者上气道三维CT图像的改变

Objective To evaluate the changes in three-dimensional computer tomography (3DCT) images of upper airway in patients with difficult tracheal intubation and provide theoretical evidence for predicting the difficult tracheal intubation. Methods Seventeen ASA Ⅰ or Ⅱ male patients, 25-60 yr old, height 165-185 era, weight 55-110 kg, body mass index 19-33 kg/m2, scheduled for elective surgery under general anesthesia, were studied. The airway condition was evaluated with Mallampati classification and Willsan score system in all patients before the operation. The patients underwent 3DCT scanning under 2 different statuses: with or without tongue protruding while opening his mouth maximally. The volume of the oropharyngeal cavity (Va1, Va2) andtongue body (Vt1, Vt2), and area of the oropharyngeal cavity (Aa1, Aa2) and tongue body (At1, At2) in the coronal position were measured before and during tongue protruding. The midline sagittal images of the upper airway were made on computer to measure the direct laryngoscope angle and vertical distance between the mandible and hyoid (MHD). Awake blind tracheal intubation was performed in all patients. The exposure of the glottis was performed after anesthesia induction and evaluated with Cormack-Lehane classification. The patients were divided into non-difficult intubation group (group NDI, Cormack-Lehane grade Ⅰ or Ⅱ) and difficult intubation group (group DI, Cormack-Lehane grade Ⅲ or Ⅳ) according to Cormack-Lehane classification. Results There were 8 patients in group NDI, and 9 patients in group DI. There was no significant difference in the indices before tongue protruding between group DI and NDI (P>0.05). Va2, Va1 - Va1, Aa2, Aa1 - Aa2, and At1- At2 weresignificanfly smaller, MHD was significantly longer and Va1,/Vt1- Va2/Vt2was significantly larger in group DI than in group NDI (P < 0.05 or 0.01). Va2 and Aa2 were significantly smaller than Va1 and Aa1 in group DI respectively (P < 0.05). Conclusion The changes in 3DCT images of the upper airway in patients with difficult tracheal intubation are mainly presented as smaller volume and area of the oropharyngeal cavity, larger difference value of the ratio of cavity volume to tongue volume and prolonged MHD.     

Lung deposition patterns of directly labelled salbutamol in normal subjects and in patients with reversible airflow obstruction.

BACKGROUND--Earlier studies of aerosol deposition in the lungs have relied on indirect labelling of Teflon spheres of a similar size distribution to the drug in question and have assumed similar aerodynamic properties. Using a modification of a new technique for directly labelling salbutamol, the deposition of salbutamol within the lungs of normal subjects and patients with asthma has been studied with the use of a metered dose inhaler (MDI) alone, an MDI with a spacer device, and a dry powder inhaler (DPI). METHOD--Salbutamol was directly labelled with technetium-99m and placed in an MDI or DPI. Ten normal subjects and 19 patients with asthma inhaled 200 micrograms of salbutamol by means of the MDI alone, the MDI with a spacer device attached, and by DPI on separate days. Deposition was assessed by a dual headed gamma camera after inhalation of the drug. RESULTS--The total mean (SD) percentage deposition of the drug in the normal subjects was 21.6% (8.9%) with the MDI alone, 20.9% (7.8%) with the MDI with spacer, and 12.4% (3.5%) with the DPI. For the patients, the mean percentage deposition was 18.2% (7.8%) with the MDI alone, 19.0% (8.9%) with the MDI and spacer, and 11.4% (5.0%) with the DPI. Bronchodilatation achieved by the patients was similar with all three techniques. Mean peripheral lung deposition was significantly greater with a spacer device than when the MDI was used alone in both normal subjects (49.4% (6.1%) v 44.1% (9.9%)) and patients (38.6% (11.1%) v 30.4% (9.4%)). CONCLUSIONS--The deposition of directly labelled salbutamol from an MDI is greater than previously estimated by indirect labelling techniques. The deposition of labelled salbutamol from a DPI, however, is little different from that measured by indirect techniques.     

Awake tracheal intubation using the Sensascope™ in 13 patients with an anticipated difficult airway

We present the use of the SensaScope?, an S‐shaped rigid fibreoptic scope with a flexible distal end, in a series of 13 patients at high risk of, or known to have, a difficult intubation. Patients received conscious sedation with midazolam or fentanyl combined with a remifentanil infusion and topical lidocaine to the oral mucosa and to the trachea via a trans‐cricoid injection. Spontaneous ventilation was maintained until confirmation of tracheal intubation. In all cases, tracheal intubation was achieved using the SensaScope. The median (IQR [range]) insertion time (measured from the time the facemask was taken away from the face until an end‐expiratory CO₂ reading was visible on the monitor) was 58 s (38–111 [28–300]s). In nine of the 13 cases, advancement of the SensaScope into the trachea was easy. Difficulties included a poor view associated with a bleeding diathesis and saliva, transient loss of spontaneous breathing, and difficulty in advancing the tracheal tube in a patient with unforeseen tracheal narrowing. A poor view in two patients was partially improved by a high continuous flow of oxygen. The SensaScope may be a valuable alternative to other rigid or flexible fibreoptic scopes for awake intubation of spontaneously breathing patients with a predicted difficult airway.     

A comparison of the GlideScope with the Macintosh laryngoscope for tracheal intubation in patients with simulated difficult airway

We compared the use of the GlideScope and the conventional Macintosh laryngoscope in a simulated difficult airway. The primary hypothesis was that time to intubation would be shorter using the GlideScope than using the Macintosh laryngoscope. After obtaining approval from the ethics committee and written informed consent, we recruited 60 ASA 1 and 2 patients to our randomized controlled trial. Group G (n = 30) had tracheal intubation performed using the GlideScope and Group M (n = 30) were intubated using a Macintosh laryngoscope. We simulated a difficult airway in each patient by having an experienced assistant provide in-line manual stabilization of the head and neck. We recorded the best laryngeal view; difficulty of the tracheal intubation; time taken for successful tracheal intubation; manoeuvre needed to aid tracheal intubation and complications associated with the tracheal intubation. The median Cormack and Lehane grade was significantly better in Group G than Group M. Group G had a significantly shorter intubation time than group M (mean 41.8s +/- SD 20.2 vs mean 56.2s +/- 26.6, P < 0.05). The GlideScope improved the laryngeal view and decreased time for tracheal intubation time when compared with the Macintosh laryngoscope in patients with simulated difficult airway. The GlideScope may be a good alternative for managing the difficult airway but clinical trials evaluating its use on patients with an actual difficult airway are needed.     

Randomised comparison of Pentax AirwayScope and Glidescope for tracheal intubation in patients with normal airway anatomy

We compared intubating characteristics of the Pentax AirwayScope and Glidescope in a randomised controlled trial involving 140 patients. We found significantly shorter intubation times with mean (SD) 21.3 (12.3) vs 30.2 (13.2) s, lower intubating difficulty scores 4.4 (10.4) vs 12.8 (16.3) p < 0.001, and better grade 1 laryngeal views with the Pentax AirwayScope (95.7 vs 81.4%, p = 0.015). Significantly more optimisation manoeuvres were needed to successfully intubate with the Glidescope, with significant inability to align the tip of the tracheal tube with the glottic opening with the Glidescope in 9 (13%) vs no patients, p = 0.013. There was more mucosal bleeding (4 (5.7%) vs 1 (1.4%), p = 0.366), more lip bleeding (3 (4.3%) vs 1 (1.4%), p = 0.620) and significantly more postoperative sorethroat, 13 (18.6%) vs 0, p < 0.001 associated with the Glidescope.     

Effect of regular inhaled salbutamol on airway responsiveness and airway inflammation in rhinitic non-asthmatic subjects

BACKGROUND: Regular, inhaled beta 2 agonists may increase airway responsiveness in asthmatic subjects. The mechanism is not known but may be via an increase in airway inflammation. A study was undertaken to examine the effect of regular inhaled salbutamol on airway responsiveness to methacholine and hypertonic saline, on the maximal response plateau to methacholine, and on inflammatory cells in induced sputum in rhinitic non-asthmatic subjects. METHODS: Thirty subjects with a baseline maximal response plateau of > 15% fall in forced expiratory volume in one second (FEV1) entered a randomised, placebo controlled, parallel trial consisting of two weeks run in, four weeks of treatment, and two weeks washout. Methacholine challenges were performed at the beginning of the run in period, before treatment, after treatment, and after washout. Hypertonic saline challenges were performed before and after treatment and induced sputum samples were collected for differential cell counting. RESULTS: There was no change in airway responsiveness, maximal response plateau to methacholine, or in induced sputum eosinophils or mast cells. The maximum fall in FEV1 after hypertonic saline increased in the salbutamol group (median change 6.0%, interquartile range (IQR) 11.0) but did not change in the placebo group (median change 1.3%, IQR 5.5). CONCLUSIONS: Regular inhaled salbutamol for four weeks increases airway responsiveness to hypertonic saline but does not alter airway responsiveness to methacholine or cells in induced sputum in non-asthmatic individuals with rhinitis. The relevance of these findings to asthmatic subjects has not been established.