Clinical assessment of a plastic optical fiber stylet for human tracheal intubation.

BACKGROUND: The authors compared the performance of a prototype intubation aid that incorporated plastic illumination and image guides into a stylet with fiberoptic bronchoscopy and direct laryngoscopy for tracheal intubation by novice users. METHODS: In a randomized, nonblinded design, patients were assigned to direct laryngoscopy, fiberoptic bronchoscopy, or imaging stylet intubation groups. The quality of laryngeal view and ease with which it was attained for each intubation was graded by the laryngoscopist. Time to intubation was measured in 1-min increments. A sore-throat severity grade was obtained after operation. RESULTS: There were no differences in demographic, physical examination, or surgical course characteristics among the groups. The laryngoscope produced an adequate laryngeal view more easily than did the imaging stylet or bronchoscope (P = 0.001) but caused the highest incidence of postoperative sore throat (P<0.05). Although the time to intubation for direct laryngoscopy was shorter than for imaging stylet, which was shorter than fiberoptic bronchoscopy (P<0.05), the quality of laryngeal view with the imaging stylet was inferior to both direct laryngoscopy and fiberoptic bronchoscopy techniques (P<0.05). CONCLUSIONS: Novices using the imaging stylet produce fewer cases of sore throat (compared with direct laryngoscopy) and can intubate faster than when using a bronchoscope in anesthetized adult patients. The imaging stylet may be a useful aid for tracheal intubation, especially for those unable to maintain skills with a bronchoscope.     

Mandibular Advancement Improves the Laryngeal View during Direct Laryngoscopy Performed by Inexperienced Physicians

Background: When oral or nasal fiberoptic laryngoscopy is attempted, mandibular advancement has been reported to improve the laryngeal view. The authors hypothesized that mandibular advancement may also improve the laryngeal view during direct laryngoscopy.

Methods: Forty patients undergoing elective surgery under general anesthesia were included in this study. After establishment of an adequate level of anesthesia and muscle relaxation, direct laryngoscopy was performed by inexperienced physicians. Four different maneuvers-simple direct laryngoscopy without any assistance (C), simple direct laryngoscopy with mandibular advancement (M), simple direct laryngoscopy with the BURP maneuver (backward, upward, rightward pressure maneuver of the larynx; B), and simple direct laryngoscopy with both mandibular advancement and the BURP maneuver (BM)-were attempted in each subject, and the laryngeal aperture was videotaped with each procedure. An instructor in anesthesiology who was blinded to the procedure evaluated the visualization by reviewing videotape off-line, using the Cormack-Lehane classification system (grades I-IV) and a rating score within each subject (1 = best view; 4 = poorest view). The Friedman test followed by the Student-Newman-Keuls test was performed for statistical comparison. P < 0.05 was considered significant.

Results: The laryngeal view was improved with M and B when compared with C (P < 0.05 by both rating and Cormack-Lehane evaluation). BM was the most effective method to visualize the laryngeal aperture (P < 0.05, vs. B and M by rating evaluation), whereas B and M were the second and the third most effective methods, respectively. No statistical difference was observed between B and M with the Cormack-Lehane classification.     

A comparison of bullard laryngoscope and intubating laryngeal mask using fiberoptic guidance for tracheal intubation

The purpose of this study is to compare the success rate of tracheal intubation, intubation time and laryngoscopic view of the larynx by Bullard laryngoscope or by intubating laryngeal mask using fiberoptic guidance in 50 patients. Following a standardized induction protocol, conventional laryngoscopic view by Macintosh's laryngoscope was obtained and classified by Cormack's grades. We measured the times from incertion of laryngoscopy or laryngeal mask until obtaining the best view of the larynx and until tracheal intubation. A best view by Bullard laryngoscopy or by fiberoscopy through the laryngeal mask was classified by Cormack's grades. The success rate of tracheal intubation was higher by Bullard laryngoscopy than by intubating laryngeal mask. The durations of laryngoscopy and tracheal intubation were significantly shorter and Cormack's grades were significantly lower by Bullard laryngoscopy than by laryngeal mask and fiberscopy. These results demonstrate that tracheal intubation by Bullard laryngoscope is faster and more successful compared with intubating laryngeal mask using fiberoptic guidance.     

Hemodynamic and catecholamine response to tracheal intubation: direct laryngoscopy compared with fiberoptic intubation

STUDY OBJECTIVE: To compare the stress response following tracheal intubation using direct laryngoscopy to that using fiberoptic bronchoscopy technique. DESIGN: Randomized, prospective study. SETTING: Operating rooms in a teaching hospital. PATIENTS: 51 ASA physical status I and II patients who were scheduled for an elective surgery with general anesthesia. INTERVENTIONS: Patients were randomly assigned to receive either direct laryngoscopy or fiberoptic orotracheal intubation, as part of general anesthesia. A uniform protocol of anesthetic medications was used. MEASUREMENTS: Blood pressure and heart rate were measured before induction, before endotracheal intubation, and 1, 2, 3, and 5 minutes afterwards. Catecholamine (epinephrine and norepinephrine) blood samples were drawn before the induction, and 1 and 5 minutes after intubation. MAIN RESULTS: Duration of intubation was shorter in the direct laryngoscopy group (16.9 (16.9 +/- 7.0 sec, range 8 to 40) compared with the fiberoptic intubation group (55.0 +/- 22.5 sec, range 29 to 120), p < 0.0,001. In both groups, blood pressure and heart rate were significantly increased at 1, 2, and 3 minutes after intubation, but there was no significant difference between the two study groups. Catecholamine levels did not increase after intubation and did not correlate with the hemodynamic changes. CONCLUSIONS: The use of either direct laryngoscopy or fiberoptic bronchoscopy produces a comparable stress response to tracheal intubation. Catecholamine levels do not correlate with the hemodynamic changes.     

Evaluation of Tracheal Intubation Difficulty in Patients with Cervical Spine Immobilization: Fiberoptic (WuScope) Versus Conventional Laryngoscopy

Background: The WuScope is a rigid, fiberoptic laryngoscope designed to facilitate tracheal intubation without the need for head extension. The study evaluated the WuScope in anesthetized patients with neck immobilization.

Methods: Patients were randomized to one of two groups: those receiving fiberoptic laryngoscopy (WuScope, n = 43) and those receiving conventional laryngoscopy (Macintosh blade, n = 44). Manual in-line stablization of the cervical spine was done during intubation. Seven parameters of intubation difficulty were measured (providing an intubation difficulty scale score): number of operators, number of attempts, number of techniques, Cormack view, lifting force, laryngeal pressure, and vocal cord position.

Results: Successful intubation occurred in 95% of patients in the fiberoptic group and in 93% of patients in the conventional group. There were no differences in number of attempts. In the fiberoptic group, 79% of patients had an intubation difficulty scale score of 0, representing an ideal intubation: that is, one performed by the first operator on the first attempt using the first technique with full glottic visualization. Only 18% of patients in the conventional group had an intubation difficulty scale score of 0 (P < 0.001). More patients had Cormack grade 3 or 4 views with conventional than with fiberoptic laryngoscopy (39 vs. 2%, P < 0.001). Intubation times in patients with one attempt were slightly longer in the fiberoptic (median, 25th--75th percentiles: 30, 23-53 s) compared with the conventional group (24, 17-30 s, P < 0.05). Corresponding times in patients requiring > one attempt were 155 (range, 112-201) s and 141 (range, 95-186) s in the fiberoptic and conventional groups, respectively (P value not significant).     

Evaluation of tracheal intubation difficulty in patients with cervical spine immobilization: fiberoptic (WuScope) versus conventional laryngoscopy.

BACKGROUND: The WuScope is a rigid, fiberoptic laryngoscope designed to facilitate tracheal intubation without the need for head extension. The study evaluated the WuScope in anesthetized patients with neck immobilization. METHODS: Patients were randomized to one of two groups: those receiving fiberoptic laryngoscopy (WuScope, n = 43) and those receiving conventional laryngoscopy (Macintosh blade, n = 44). Manual in-line stablization of the cervical spine was done during intubation. Seven parameters of intubation difficulty were measured (providing an intubation difficulty scale score): number of operators, number of attempts, number of techniques, Cormack view, lifting force, laryngeal pressure, and vocal cord position. RESULTS: Successful intubation occurred in 95% of patients in the fiberoptic group and in 93% of patients in the conventional group. There were no differences in number of attempts. In the fiberoptic group, 79% of patients had an intubation difficulty scale score of 0, representing an ideal intubation: that is, one performed by the first operator on the first attempt using the first technique with full glottic visualization. Only 18% of patients in the conventional group had an intubation difficulty scale score of 0 (P < 0.001). More patients had Cormack grade 3 or 4 views with conventional than with fiberoptic laryngoscopy (39 vs. 2%, P < 0.001). Intubation times in patients with one attempt were slightly longer in the fiberoptic (median, 25th-75th percentiles: 30, 23-53 s) compared with the conventional group (24, 17-30 s, P < 0.05). Corresponding times in patients requiring > one attempt were 155 (range, 112-201) s and 141 (range, 95-186) s in the fiberoptic and conventional groups, respectively (P value not significant). CONCLUSIONS: Compared with conventional laryngoscopy, tracheal intubation using the fiberoptic laryngoscope was associated with lower intubation difficulty scale scores and better views of the laryngeal aperture in patients with cervical imnmobilization. However, there were no differences in success rates or number of intubation attempts.     

Management of airway in patients with laryngeal tumors

STUDY OBJECTIVE: To describe our systematic approach to securing the airway in patients with laryngeal tumors, developed over a 10-year period. DESIGN: Retrospective analysis. SETTING: University-affiliated veterans administration medical center. PATIENTS: Eight hundred one patients presenting for laryngeal tumor surgery in a 10-year period, 285 of whom underwent tracheostomy (25 with local anesthesia and 260 with general anesthesia). INTERVENTIONS: Preoperative examination, including history, physical examination, computed axial tomography and/or magnetic resonance imaging, and ear, nose, and throat surgeons' evaluation via indirect laryngoscopy or fiberoptic bronchoscopy were performed before the anesthesiologist's interventions. Local (topical) anesthesia and mild sedation were used for laryngeal evaluation with fiberoptic bronchoscopy. Tumor grade was then established, which determined how the airway would be secured: general anesthesia induction, receive topical anesthesia for awake, direct laryngoscopy, and tracheal intubation, or undergo tracheostomy with local anesthesia. MEASUREMENTS AND MAIN RESULTS: When the airway was secured, surgeons performed the biopsy, (any) tumor debulking, laser excision, or tracheostomy to establish both the airway and the diagnosis. Pulmonary function, including flow-volume loops and blood gas analysis were also useful in evaluating the degree of obstruction and gas exchange. In the event of respiratory distress, tracheostomy was performed after tracheal intubation or with local anesthesia, followed by direct laryngoscopy and biopsy. Depending on the diagnosis, further surgery and radiation treatment were planned next. CONCLUSIONS: With these guidelines, we have reduced the frequency of emergencies because of a lost airway, bleeding, or dislodging of tumor.     

Mandibular advancement improves the laryngeal view during direct laryngoscopy performed by inexperienced physicians

BACKGROUND: When oral or nasal fiberoptic laryngoscopy is attempted, mandibular advancement has been reported to improve the laryngeal view. The authors hypothesized that mandibular advancement may also improve the laryngeal view during direct laryngoscopy. METHODS: Forty patients undergoing elective surgery under general anesthesia were included in this study. After establishment of an adequate level of anesthesia and muscle relaxation, direct laryngoscopy was performed by inexperienced physicians. Four different maneuvers--simple direct laryngoscopy without any assistance (C), simple direct laryngoscopy with mandibular advancement (M), simple direct laryngoscopy with the BURP maneuver (backward, upward, rightward pressure maneuver of the larynx; B), and simple direct laryngoscopy with both mandibular advancement and the BURP maneuver (BM)--were attempted in each subject, and the laryngeal aperture was videotaped with each procedure. An instructor in anesthesiology who was blinded to the procedure evaluated the visualization by reviewing videotape off-line, using the Cormack-Lehane classification system (grades I-IV) and a rating score within each subject (1 = best view; 4 = poorest view). The Friedman test followed by the Student-Newman-Keuls test was performed for statistical comparison. P < 0.05 was considered significant. RESULTS: The laryngeal view was improved with M and B when compared with C (P < 0.05 by both rating and Cormack-Lehane evaluation). BM was the most effective method to visualize the laryngeal aperture (P < 0.05, vs. B and M by rating evaluation), whereas B and M were the second and the third most effective methods, respectively. No statistical difference was observed between B and M with the Cormack-Lehane classification. CONCLUSION: Mandibular advancement improves the laryngeal view during direct laryngoscopy performed by inexperienced physicians.     

Endotracheal intubation with a gum-elastic bougie in unanticipated difficult direct laryngoscopy: comparison of a blind technique versus indirect laryngoscopy with a laryngeal mirror

We evaluated the efficacy of intubation over a gum-elastic bougie by using either a blind technique or indirect laryngoscopy with a laryngeal mirror in patients with unexpected difficult direct laryngoscopy. In a prospective study, 60 consecutive patients with an unexpected Grade III or IV direct laryngoscopy were randomly allocated for intubation with a gum-elastic bougie either blindly (Group 1) or by indirect laryngoscopy with a laryngeal mirror (Group 2). We evaluated the failure rate of each method of intubation, complications related to either method, and the time required for intubation. Out of 725 patients evaluated over a 2-mo period, 60 patients (8.3%) had a Grade III laryngoscopy, and 30 of these were randomized into each group. There were 8 failed intubations in Group 1 compared with 1 failed intubation in Group 2 (P < 0.05). All eight failures in the blind intubation group ended with esophageal intubation. No additional complications were noted in either group. The time required for endotracheal intubation with each group was not significantly different (45 +/- 10 s versus 44 +/- 11 s). We conclude that intubation with a gum-elastic bougie had a lower failure rate using indirect laryngoscopy with a laryngeal mirror than a traditional blind technique. IMPLICATIONS: We evaluated the efficacy of intubation over a gum-elastic bougie by using either a blind technique or a laryngeal mirror. Intubation with a gum-elastic bougie had a lower failure rate using indirect laryngoscopy with a laryngeal mirror (P < 0.05) than a traditional blind technique.     

Left endobronchial intubation with a double‐lumen tube using direct laryngoscopy or the Trachway® video stylet

We compared direct laryngoscopy with a Macintosh blade vs indirect bronchoscopy with a Trachway^® stylet, for endobronchial intubation with a left‐sided double‐lumen tube. We allocated participants scheduled for thoracic surgery and who had normal predicted laryngoscopy, 30 to each group. The mean (SD) intubation times with laryngoscope and Trachway were 48 (11) s vs 28 (4) s, respectively, p < 0.001. The rates of hoarseness on the first postoperative day, categorised as none/mild/moderate/severe, were 10/12/7/1 and 22/6/2/0, respectively, p = 0.008, without differences on subsequent days. Left endobronchial intubation with a double‐lumen tube is slower using direct laryngoscopy and causes more hoarseness than indirect bronchoscopy with a Trachway stylet.     

Difficult Intubation in Acromegalic Patients: Incidence and Predictability

Background: Previous studies have suggested that the incidence of difficult intubation in acromegalic patients is higher than in normal patients. However, these studies were retrospective and did not include preoperative assessment of the airways. The aims of this study were to determine the incidence of difficult intubation and to assess the usefulness of preoperative tests in predicting difficult laryngoscopy.

Methods: One hundred twenty-eight consenting acromegalic patients requiring general anesthesia and tracheal intubation were studied. Preoperatively, Mallampati classification, thyromental distance, and head and neck movement were determined in each patient. After induction of anesthesia and muscle paralysis, laryngoscopic grade was assessed during direct laryngoscopy; Cormack and Lehane grade III or IV were classified as difficult. The association of individual airway assessment with laryngeal view was evaluated using the Fisher exact test. Predictors of difficult laryngoscopy were evaluated by calculating their sensitivity and specificity.

Results: Laryngoscopy was difficult (grade III) in 33 of 128 patients (26%). Application of external laryngeal pressure improved laryngeal visualization to grade II in 20 of these 33 patients. In the remaining 13 patients (10%), intubation was difficult (more than two attempts, blade change, use of gum-elastic bougie). Mallampati classes 3 and 4 were significantly related to laryngoscopy grade III (Fisher exact test, P = 0.001).     

difficult airway management: comparison of the bullard laryngoscope with the video-optical intubation stylet

PURPOSE: To evaluate, whether the video-optical intubation stylet (VOIS) was more successful for difficult tracheal intubation than the Bullard laryngoscope (BL). METHODS: An intubation mannequin head was modified so that, using a Macintosh blade size 3, only the epiglottis was visible at direct laryngoscopy, representing a grade III laryngoscopic view. Forty anesthesiologists attempted tracheal intubation using each technique. Tracheal intubation with the Bullard laryngoscope was performed using the attached non-malleable intubating stylet preloaded with an endotracheal tube. The video-optical intubation stylet inserted into an endotracheal tube was used with direct laryngoscopy. During conventional laryngoscopy, the video-view from the stylet tip allowed the tracheal tube to be guided behind the epiglottis into the trachea. Ten attempts with each technique were performed by each anesthesiologist in randomized order. Intubation time, and failed intubation (> 60 sec/esophageal intubation) were recorded. The operators assessed the degree of difficulty of each method using a Likert-scale. RESULTS: Mean intubation time (19.2+/-4.5 sec for the BL and 18.8+/-4.6 sec for the VOIS) was almost the identical. The video-optical intubation stylet was associated with fewer failed intubations (8 vs. 41; P<0.005) and had a lower degree of difficulty (1.7+/-0.65 for the VOIS and 2.6+/-0.74 for the BL; P<0.0001). No correlation was found between the anesthesiologist's experience and mean intubation time, estimated degree of difficulty or number of unsuccessful intubation. CONCLUSION: The video-optical intubation stylet was a more effective and simpler intubation device to facilitate difficult tracheal intubation than the Bullard laryngoscope.     

Left molar approach improves laryngeal view in patients with simulated limitation of cervical movements

Background: Immobilized cervical spine, because of either diseases or stabilizing devices, poses considerable difficulties with endotracheal intubation due to poor laryngoscopic view. The left molar (LM) approach has been shown to be useful in difficult sporadic intubation cases. We evaluated efficacy of this approach of laryngoscopy to improve laryngeal view in patients with simulated limitation of cervical movements.
Methods: Thirty patients of American Society of Anesthesiologists grade I/II, who were scheduled to undergo routine surgical procedures under general anaesthesia and endotracheal intubation, were studied. A two-piece semi-rigid cervical collar was used to immobilize the cervical spine. Under standardized anaesthesia and neuromuscular blocking agent, conventional laryngoscopy using a curved Macintosh blade was performed and glottic view was recorded with and without optimal external laryngeal manipulation (OELM). Subsequently, in the same subjects the laryngoscope blade was withdrawn and re-inserted through the LM approach and glottic view was recorded with and without OELM followed by tracheal intubation.
Results: With the conventional approach, laryngeal view was recorded as grade II in five patients, grade III in 24 patients, and grade IV in one patient. However, with the LM approach, laryngeal view was grade I in 25 patients, grade II in five patients, and grade III or IV in none ( P <0.001). Tracheal intubation with the LM approach required the use of a flexible stylet to guide the tube tip into the larynx.
Conclusions: The laryngeal view is improved by the LM approach in patients with simulated limited cervical movements with a high success rate of tracheal intubation, but requires orientation for negotiation of the tube through the narrow oropharyngeal space available.     

Efficacy and safety of videolaryngoscopy versus direct laryngoscopy in paediatric intubation: A meta-analysis of 27 randomized controlled trials

ObjectiveAnatomical and physiological differences in paediatric and adult airways make intubation of paediatric patients a challenge. This study aimed to compare the efficacy and safety of video laryngoscopy (VL) to direct laryngoscopy (DL) on intubation outcomes in paediatric patients.DesignSystematic review and meta-analysis.SettingOperating room.PatientsPaediatric patients who needed tracheal intubation.InterventionVideo laryngoscopy or direct laryngoscopy.MeasurementsElectronic searches in PubMed, Embase, and the Cochrane Library were performed to identify relevant randomized controlled trials published through January 2020. Outcomes included time to intubate, intubation failure at first attempt, Cormack-Lehane laryngeal view grade, intubation difficulty scale (IDS), percentage of glottic opening score (POGO), optimal external laryngeal manipulation (OLEM), and complications. Relative risks and weighted mean difference (WMD), with 95% CI, were employed to calculate summary results using a random-effects model.Main resultsOverall, 27 trials including 2461 paediatric patients were analysed. Children with video laryngoscopy intubation required longer time to intubate than direct laryngoscopy intubation (WMD 3.41, 95% CI: 1.29–5.53, P = 0.002), whereas infants receiving video laryngoscopy and direct laryngoscopy intubation experienced similar time to intubate (WMD 1.72, 95% CI: −1.09-4.54, P = 0.230). No significant differences were observed on intubation failure at first attempt between video laryngoscopy and direct laryngoscopy intubations in children and infants, respectively. Video laryngoscopy improved the POGO and intubation trauma but not Cormack-Lehane laryngeal view grade, IDS, external laryngeal manipulation, hoarseness, or oxygen desaturation.ConclusionsCompared with direct laryngoscopy intubation, there were no benefits for paediatric patients with video laryngoscopy on time to intubate and failure at first attempt, but there were benefits with regard to POGO and intubation trauma.     

Morbid obesity and tracheal intubation

The tracheas of obese patients may be more difficult to intubate than those of normal-weight patients. We studied 100 morbidly obese patients (body mass index >40 kg/m(2)) to identify which factors complicate direct laryngoscopy and tracheal intubation. Preoperative measurements (height, weight, neck circumference, width of mouth opening, sternomental distance, and thyromental distance) and Mallampati score were recorded. The view during direct laryngoscopy was graded, and the number of attempts at tracheal intubation was recorded. Neither absolute obesity nor body mass index was associated with intubation difficulties. Large neck circumference and high Mallampati score were the only predictors of potential intubation problems. Because in all but one patient the trachea was intubated successfully by direct laryngoscopy, the neck circumference that requires an intervention such as fiberoptic bronchoscopy to establish an airway remains unknown. We conclude that obesity alone is not predictive of tracheal intubation difficulties. IMPLICATIONS: In 100 morbidly obese patients, neither obesity nor body mass index predicted problems with tracheal intubation. However, a high Mallampati score (greater-than-or-equal to 3) and large neck circumference may increase the potential for difficult laryngoscopy and intubation.     

预期困难气道患者喉罩辅助纤维支气管镜引导气管插管的研究

目的 探讨在预期困难气道患者中采用喉罩辅助纤维支气管镜(fiberoptic bronchoscope,FOB)引导气管插管的应用价值. 方法 择期经口气管插管全身麻醉手术预测困难气道患者24例,ASA Ⅰ或Ⅱ级,入选患者达到以下1种或几种条件为预期困难气道:1.5 cm＜张口度＜3 cm,甲颏间距＜6 cm,头颈活动度＜80°,Mallampati分级Ⅲ、Ⅳ级.采用随机数字表法分为喉罩辅助FOB组(F组)和直接喉镜组(L组),每组12例.F组采用喉罩辅助FOB引导下气管插管;L组在直接喉镜暴露下经口气管插管,3次试插未成功者改行F组方法试插.记录两组患者的气道评估情况、气管插管前(基础值)和插管后3 min的MAP和HR、成功插管的次数及术后的并发症的发生情况. 结果 插管前两组气道评估差异无统计学意义(P＞0.05).与插管前相比,L组患者插管后MAP和HR显著增加,差异有统计学意义(P＜0.05).两组插管后的MAP和HR比较,差异有统计学意义(P＜0.05).F组气管插管一次成功率为75％,3次以内插管合计总成功率为100％;L组气管插管一次成功率为25％,3次以内插管合计总成功率为50％;6例L组患者直接喉镜3次插管不成功后改为喉罩辅助FOB插管,2例1次成功,4例2次成功;F组一次插管成功率和3次插管总成功率均显著高于L组,两组比较差异有统计学意义(P＜0.05).与L组插管时间(161±26)s比较,F组插管时间(81±9)s明显缩短,差异有统计学意义(P＜0.05).F组有2例术后轻度咽喉疼痛,L组有6例术后咽喉疼痛明显和轻度声嘶、2例轻度咽痛. 结论 对术前预期为困难气道的患者采用喉罩辅助FOB引导气管插管可显著提高插管的成功率,降低直接喉镜反复试插引起的术后并发症,具有一定的临床应用价值.     

The combination of a fiberoptic stylet and a McCoy laryngoscope facilitates tracheal intubation in difficult airway cases

Purpose. Fiberoptic stylets are considered useful for difficult airway management. In the present study, we assessed the usefulness of a fiberoptic stylet when the stylet was used with a Macintosh or a McCoy laryngoscope. Methods. Twenty-four patients, whose airways were graded as Cormack grade III, were studied. We compared the times required for tracheal intubation when the fiberoptic stylet was used with a Macintosh direct laryngoscope and when it was used with a McCoy laryngoscope. Cormack grade III was subdivided into IIIa (with distance between the epiglottis and the posterior wall of the pharynx) and IIIb (with no distance between the epiglottis and the posterior wall of the pharynx), according to the view of the vocal cords by the laryngoscope. Results. The intubation time in grade IIIb patients, who were intubated by the concurrent use of the fiberoptic stylet and the McCoy laryngoscope (28 ± 4 s), was not significantly different from that in grade IIIa patients (28 ± 10 s). The intubation time in grade IIIb patients, who were intubated by the concurrent use of the fiberoptic stylet and the Macintosh laryngoscope (52 ± 8 s), was significantly longer than that in grades IIIa (28 ± 10 s; P < 0.01) or IIIb with the McCoy laryngoscope (28 ± 4 s; P < 0.01). Conclusion. The combination of a new handy fiberoptic stylet and a McCoy laryngoscope facilitated tracheal intubation of patients whose airway had no distance between the epiglottis and the posterior wall of the pharynx in laryngoscopic vocal cord view. Received: September 8, 2000 / Accepted: January 22, 2001     

Management choices for the difficult airway by anesthesiologists in Canada

PURPOSE: This study assessed difficult airway management, training and equipment availability among Canadian anesthesiologists. METHODS: A postal survey of active members of the Canadian Anesthesiologists' Society was conducted in 2000. Respondents chose an induction condition and intubation technique for each of ten difficult airway scenarios. Availability of airway devices in their workplaces was assessed. Chi square analyses were used to compare groups. A P value of < 0.05 was considered statistically significant. RESULTS: Eight hundred and thirty-three of 1702 (49%) surveys were returned. Staff comprised 88%, and residents 12%. Fifty-five percent had attended a difficult airway workshop within five years and 30% received mannequin airway training during residency. Direct laryngoscopy (48%) or fibreoptic bronchoscopy (34%) were the preferred techniques for intubation. For laryngeal, subglottic and unstable cervical spine scenarios, awake intubation with fibreoptic bronchoscope was most widely chosen. Asleep intubation with direct laryngoscopy was most commonly selected for trauma scenarios. Availability of difficult airway equipment varied between regions and types of hospital. Cricothyroidotomy equipment and difficult airway carts were not universally available. CONCLUSIONS: Our survey assessed current preferences, training and equipment availability for the difficult airway amongst Canadian anesthesiologists. Direct laryngoscopy and fibreoptic bronchoscopy were the preferred technique for intubation despite widespread availability of newer airway equipment. Lack of certain essential airway equipment and difficult airway training should be addressed.     

The GlideScope®-specific rigid stylet and standard malleable stylet are equally effective for GlideScope® use

PURPOSE: The GlideScope videolaryngoscope usually provides excellent glottic visualization, but directing an endotracheal tube (ETT) through the vocal cords can be challenging. The goal of the study was to compare the dedicated GlideScope-specific rigid stylet to the standard malleable stylet, assessed by time to intubation (TTI). METHODS: Eighty patients requiring orotracheal intubation for elective surgery were randomly allocated to either the GlideScope rigid stylet (GRS) or a standard malleable stylet to facilitate intubation using the GlideScope. Time to intubation was recorded by blinded assessors; operators were blinded until after laryngoscopy. The operator assessed the ease of intubation using a visual analogue scale (VAS). The number of intubation attempts, number of failures, glottic grades, and use of external laryngeal manipulation were documented. RESULTS: The median TTI was 42.7 sec (inter-quartile range (IQR) 38.9-56.7) for the GRS group compared to 39.9 sec (IQR 34.1-48.2) for the control group (P=0.07). The median VAS score for ease of intubation was 20 (IQR 12.0-33.0) for the GRS group compared to 18 (IQR 9.5-29.5) for the control group (P=0.21). There was no significant difference in TTI or VAS between stylets. The overall incidence of a Cormack-Lehane grade I or II glottic view was 98%. CONCLUSIONS: In a group of experienced operators using the GlideScope, the dedicated GRS and the standard malleable ETT stylet are equally effective in facilitating endotracheal intubation.     

改良普通喉罩辅助纤维支气管镜气管插管在困难气道患者中的应用

目的观察改良普通喉罩辅助纤维支气管镜(fiberoptic bronchoscope,FOB)气管插管在困难气道患者中的应用效果。方法选择经熟练麻醉医师使用直接喉镜插管2次失败的择期全麻手术患者40例,男21例,女19例,年龄30~55岁,ASAⅠ或Ⅱ级,随机分为两组,每组20例。研究组(LMA-FOB组)将普通喉罩进行改良(剪开喉罩出口栅栏分隔处,剪短通气管),辅助FOB气管插管;对照组(FOB组)经口垫直接使用FOB气管插管。观察咽部解剖结构显露分级,记录一次插管成功率及插管时间,记录拔除喉罩带血和术后咽喉部疼痛、声音嘶哑等不良反应的发生情况。结果与FOB组比较,LMA-FOB组咽部解剖结构显露分级明显提高(Ⅰ/Ⅱ/Ⅲ/Ⅳ级:15/4/1/0vs.8/4/5/3,P0.05),一次插管成功率明显提高(90%vs.60%,P0.05),插管时间明显缩短[(75±20)s vs.(105±25)s,P0.05)]。术后LMA-FOB组仅1例喉罩带血,1例咽部轻微疼痛。结论对可能存在困难气道的患者,采用改良普通喉罩辅助纤维支气管镜引导气管插管可明显提高咽部解剖结构显露分级,提高一次插管成功率,缩短插管时间,术后无明显不良反应,是一种比较安全有效的方法,有一定的临床应用价值。