Sabine Nabecker

Evaluation of six videolaryngoscopes in 720 patients with a simulated difficult airway: a multicentre randomized controlled trial

BACKGROUND Videolaryngoscopes are aggressively marketed, but independent evaluation in difficult airways is scarce. This multicentre, prospective randomized controlled trial evaluates six videolaryngoscopes in patients with a simulated difficult airway. METHODS With ethics committee approval and written informed consent, 12 senior anaesthetists intubated the trachea of 720 patients. A cervical collar limited mouth opening and neck movement, making intubation difficult. We evaluated three unchannelled (C-MAC™ D-blade, GlideScope™, and McGrath™) and three channelled videolaryngoscopes (Airtraq™, A.P. Advance™ difficult airway blade, and KingVision™). The primary outcome was first-attempt intubation success rate. Secondary outcomes included overall success rate, laryngeal view, intubation times, and side-effects. The primary hypothesis for every videolaryngoscope was that the 95% confidence interval of first-attempt success rate is ≥90%. RESULTS Mouth opening was decreased from 46 (sd 7) to 23 (3) mm with the cervical collar. First-attempt success rates were 98% (McGrath™), 95% (C-MAC™ D-blade), 87% (KingVision™), 85% (GlideScope™ and Airtraq™), and 37% (A.P. Advance™, P<0.01). The 95% confidence interval of first-attempt success rate was >90% only for the McGrath™. Overall success, laryngeal view, and intubation times differed significantly between videolaryngoscopes (all P<0.01). Side-effects were minor. CONCLUSIONS This trial revealed differences in the performance of six videolaryngoscopes in 720 patients with restricted neck movement and limited mouth opening. In this setting, first-attempt success rates were 85-98%, except for the A.P. Advance™ difficult airway blade. Highest success and lowest tissue trauma rates were achieved by the McGrath™ and C-MAC™ D-blade, highlighting the importance of the videolaryngoscope blade design. CLINICAL TRIAL REGISTRATION ClinicalTrials.gov: identifier NCT01692535.

Randomized clinical trial comparing double-lumen tube and EZ-Blocker® for single-lung ventilation

BACKGROUND In several clinical situations, lung separation and single-lung ventilation (SLV) is essential. In these cases, the double-lumen tube (DLT) is the most widely used device. Bronchial blocker such as Univent or Arndt Blocker serves as an alternative. The EZ-Blocker(®) (EZ; AnaesthetIQ B.V., Rotterdam, The Netherlands) is a new device promising to exceed clinical performance of DLT. The aim of this study was to assess the clinical performance of EZ in comparison with conventional left-sided DLT. METHODS Forty adult patients undergoing elective thoracic surgery requiring thoracotomy and SLV were included in this study. The patients were randomly assigned to one of two groups: EZ (combined with conventional 7.5 or 8.5 mm single-lumen tube) or DLT (37 or 39 Fr left-sided DLT). Time for intubation procedure and time to verification of the correct position of EZ or DLT using fibreoptic bronchoscopy (FOB) were recorded. After surgery, a thoracic surgeon rated the quality of collapse of the lung (1-3 on a three-level scale). RESULTS Time for intubation using DLT 85.5 (54.8) s was significantly faster (P<0.001) than using EZ 192 (89.7) s, whereas time for bronchoscopy was not significantly different (P=0.556). Conditions of surgery were rated equally [DLT 1.3 (0.6) vs EZ 1.4 (0.6), P=0.681]. CONCLUSIONS Although time for intubation was longer with the EZ, the device proved to be an efficient and easy-to-use device. The EZ is a valuable alternative device to conventional DLT. Verification of the correct position of the EZ by FOB seems to be obligatory. This study was registered at http://www.clinicaltrials.gov (identifier: NCT01171560).

Hands-off time during insertion of six airway devices during cardiopulmonary resuscitation: A randomised manikin trial

INTRODUCTION Cardiopulmonary resuscitation (CPR) guidelines recommend limiting interruptions of chest compressions because prolonged hands-off (i.e., non-compression) time compromises tissue perfusion. 2010 European Resuscitation Council guidelines suggest that chest compressions should be paused less than 10 s during airway device insertion. METHODS With approval of the local ethics committee of the Medical University of Vienna and written informed consent, we recruited 40 voluntary emergency medical technicians, none of whom had advanced airway management experience. After a standardised audio-visual lecture and practical demonstration, technicians performed airway management with each six airway devices (endotracheal tube, Combitube, EasyTube, laryngeal tube, Laryngeal Mask Airway, and I-Gel) during on-going chest compressions in a randomised sequence on a Resusci Anne Advanced Simulator. Data were analysed using a mixed-effects model accounting for the repeated measurements and pair-wise comparisons among the airway devices. RESULTS The hands-off time associated with airway management using an endotracheal tube (including all intubation attempts) was 48 s (95% confidence interval: 43-53). The hands-off time for airway management using a laryngeal tube was 8.4 (3.4-16.4) s, Combitube 10.0 (4.9-15.1) s, EasyTube 11.4 (6.4-16.4) s, LMA 13.3 (8.2-18.3) s and for I-Gel 15.9 (10.8-20.9) s. Hands-off time was significantly longer with the conventional endotracheal tube than with any of the other airway systems. Only a third of the technicians successfully inserted an endotracheal tube whereas all of them successfully positioned each supraglottic device. CONCLUSION Supraglottic devices appear to be a reasonable emergency airway management strategy, even for inexperienced personnel.

A Randomized, Double-Blind Comparison of Licorice Versus Sugar-Water Gargle for Prevention of Postoperative Sore Throat and Postextubation Coughing

BACKGROUND:One small study suggests that gargling with licorice before induction of anesthesia reduces the risk of postoperative sore throat. Double-lumen tubes are large and thus especially likely to provoke sore throats. We therefore tested the hypothesis that preoperative gargling with licorice solution prevents postoperative sore throat and postextubation coughing in patients intubated with double-lumen tubes. METHODS:We enrolled 236 patients having elective thoracic surgery who required intubation with a double-lumen endotracheal tube. Patients were randomly assigned to gargle 5 minutes before induction of anesthesia for 1 minute with: (1) Extractum Liquiritiae Fluidum (licorice 0.5 g); or (2) Sirupus Simplex (sugar 5 g); each diluted in 30 mL water. Sore throat and postextubation coughing were evaluated 30 minutes, 90 minutes, and 4 hours after arrival in the postanesthesia care unit, and the first postoperative morning using an 11-point Likert scale by an investigator blinded to treatment. RESULTS:The incidence of postoperative sore throat was significantly reduced in patients who gargled with licorice rather than sugar-water: 19% and 36% at 30 minutes, 10% and 35% at 1.5 hours, and 21% and 45% at 4 hours, respectively. The corresponding estimated treatment effects (relative risks) were 0.54 (95% CI, 0.30–0.99, licorice versus sugar-water; P = 0.005), 0.31 (0.14–0.68) (P < 0.001), and 0.48 (0.28–0.83) (P < 0.001). CONCLUSION:Licorice gargling halved the incidence of sore throat. Preinduction gargling with licorice appears to be a simple way to prevent a common and bothersome complication.

Evaluation of airway management associated hands-off time during cardiopulmonary resuscitation: a randomised manikin follow-up study

IntroductionAirway management is an important component of cardiopulmonary resuscitation (CPR). Recent guidelines recommend keeping any interruptions of chest compressions as short as possible and not lasting more than 10 seconds. Endotracheal intubation seems to be the ideal method for establishing a secure airway by experienced providers, but emergency medical technicians (EMT) often lack training and practice. For the EMTs supraglottic devices might serve as alternatives.Methods40 EMTs were trained in a 1-hour standardised audio-visual lesson to handle six different airway devices including endotracheal intubation, Combitube, EasyTube, I-Gel, Laryngeal Mask Airway and Laryngeal tube. EMTs performances were evaluated immediately after a brief practical demonstration, as well as after 1 and 3 months without any practice in between, in a randomised order. Hands-off time was pair-wise compared between airway devices using a repeated-measures mixed-effects model.ResultsOverall mean hands-off time was significantly (p<0.01) lower for Laryngeal tube (6.1s; confidence interval 5.2-6.9s), Combitube (7.9s; 95% CI 6.9-9.0s), EasyTube (8.8s; CI 7.3-10.3s), LMA (10.2s; CI 8.6-11.7s), and I-Gel (11.9s; CI 10.2-13.7s) compared to endotracheal intubation (39.4s; CI 34.0-44.9s). Hands-off time was within the recommended limit of 10s for Combitube, EasyTube and Laryngeal tube after 1 month and for all supraglottic devices after 3 months without any training, but far beyond recommended limits in all three evaluations for endotracheal intubation.ConclusionUsing supraglottic airway devices, EMTs achieved a hands-off time within the recommended time limit of 10s, even after three months without any training or practice. Supraglottic airway devices are recommended tools for EMTs with lack of experience in advanced airway management.

Blind intubation of anaesthetised children with supraglottic airway devices AmbuAura-i and Air-Q cannot be recommended: A randomised controlled trial.

BACKGROUND Paediatric supraglottic airway devices AmbuAura-i and Air-Q were designed as conduits for tracheal intubation. Although fibreoptic-guided intubation has proved successful, blind intubation as a rescue technique has never been evaluated. OBJECTIVE Evaluation of blind intubation through AmbuAura-i and Air-Q. On the basis of fibreoptic view data, we hypothesised that the success rate with the AmbuAura-i would be higher than with the Air-Q. DESIGN A randomised controlled trial. SETTING University Childrens’ Hospital; September 2012 to July 2014. PATIENTS Eighty children, American Society of Anesthesiologists (ASA) class I to III, weight 5 to 50 kg. INTERVENTIONS Tracheal intubation was performed through the randomised device with the tip of a fibrescope placed inside and proximal to the tip of the tracheal tube. This permitted sight of tube advancement, but without fibreoptic guidance (visualised blind intubation). MAIN OUTCOME MEASURES Primary outcome was successfully visualised blind intubation; secondary outcomes included supraglottic airway device success, insertion times, airway leak pressure, fibreoptic view and adverse events. RESULTS Personal data did not differ between groups. In contrast to our hypothesis, blind intubation was possible in 15% with the Air-Q and in 3% with the AmbuAura-i [95% confidence interval (95% CI) 6 to 31 vs. 0 to 13%; P = 0.057]. First attempt supraglottic airway device insertion success rates were 95% (Air-Q) and 100% (AmbuAura-i; 95% CI 83 to 99 vs. 91 to 100; P = 0.49). Median leak pressures were 18 cmH2O (Air-Q) and 17 cmH2O [AmbuAura-i; interquartile range (IQR) 14 to 18 vs. 14 to 19 cmH2O; P = 0.66]. Air-Q insertion was slower (27 vs. 19 s, P < 0.001). There was no difference in fibreoptic view, or adverse events (P > 0.05). In one child (Air-Q size 1.5, tube size 3.5), the tube dislocated during device removal. CONCLUSION Ventilation with both devices is reliable, but success of blind intubation is unacceptably low and cannot be recommended for elective or rescue purposes. If intubation through a paediatric supraglottic airway device is desired, we suggest that fibreoptic guidance is used. TRIAL REGISTRATION Clinicaltrials.gov identifier: NCT01692522.

Evaluation of three unchannelled videolaryngoscopes and the Macintosh laryngoscope in patients with a simulated difficult airway: a randomised, controlled trial†

This prospective randomised, controlled trial compares the performance of three unchannelled videolaryngoscopes (KingVision™, Airtraq™, A.P. Advance™ MAC) and the standard Macintosh laryngoscope. With ethics committee approval and written informed consent, 480 patients were included. A difficult airway was created with a cervical collar, limiting mouth opening and neck movement. Primary outcome was first‐attempt orotracheal intubation success. Overall success, laryngeal view, intubation difficulty scale, handling, intubation times and side‐effects were secondary outcomes. First‐attempt success rates were: KingVision 90% (95% CI 83–94%), Airtraq 82% (74–88%), A.P. Advance MAC 49% (40–58%), Macintosh 44% (35–53%; p < 0.001). The 95% confidence interval of first‐attempt success rate was thus below 90% for all devices, but the KingVision and the Airtraq performed better than the A.P. Advance MAC and the Macintosh laryngoscope. Also, performance was better with the KingVision and the Airtraq in terms of overall success, laryngeal view, intubation difficulty scale and quality of view. Problems with tube advancement were a frequent cause of intubation failure. In summary, the KingVision and the Airtraq performed better than the A.P. Advance MAC and the Macintosh laryngoscope. Success rates of the unchannelled KingVision and Airtraq were similar to those of their channelled versions reported previously, indicating that performance largely depends on blade design rather than the presence of a channel for tube advancement.

Hemodynamic and humoral response to intubation with double-lumen endotracheal tubes versus single-lumen tubes combined with an endobronchial blocker: A randomized clinical trial

Introduction: Insertion of endotracheal tubes, especially large and relatively inflexible double-lumen tubes, provokes cardiovascular and humoral responses which can cause complications. Bronchial blockers, combined with conventional single-lumen tubes (SLT), serve as alternatives to double-lumen tubes (DLT) and may provoke less hemodynamic response. Methods: Forty adults scheduled for elective thoracic surgery requiring single-lung ventilation were randomly assigned to DLT or SLT combined with EZ-Blocker (EZ), a bronchial blocker. Heart rate and arterial blood pressure were recorded before induction of anesthesia, before laryngoscopy, after laryngoscopy, and one minute after intubation. Epinephrine, norepinephrine, and cortisol serum concentrations were assessed one minute after intubation. Results: Pre-laryngoscopy values were comparable in both groups. Mean arterial pressure significantly increased in both groups during intubation. The maximum value during intubation was significantly higher with DLT (121 ± 17 mmHg), compared to bronchial blocker (105 ± 18 mmHg, P=0.022). Heart rate increased significantly during intubation in both groups (DLT from 68 ± 9 to 86 ±11, P<0.001, bronchial blocker from 72 ±11 to 87 ± 16, P=0.002), but the increase did not differ between the groups (P=0.76). Epinephrine, norepinephrine, and cortisol serum concentrations did not increase significantly from baseline values and did not differ between the treatment groups. Conclusion: Insertion of DLT increases blood pressure more than placement of a SLT combined with bronchial blocker. However, the difference is probably not clinically important. Furthermore, there were no significant differences in heart rate or catecholamine concentrations. Clinicians should consider other factors when choosing between airway options for single-lung ventilation.

[Outdoor performance of different videolaryngoscopes on a glacier: a manikin study]

OBJECTIVES Little information about the performance of videolaryngoscopes outdoors is available. We aimed to test the hypothesis that a Macintosh direct laryngoscope would perform less well than videolaryngoscopes under difficult environmental conditions (high-altitude glacier, sun-reflecting snow). MATERIAL AND METHODS After local research ethics committee approval, this randomized controlled trial enrolled 20 physicians who intubated manikins with limited cervical extension mouth opening under 5 conditions: 1) in hospitals (indoors), 2) indoors at a high altitude, 3) outdoors on a glacier in sunlight without sunglasses, 4) outdoors on a glacier with sunglasses, and 5) outdoors on a glacier with the physician and manikin covered with a blanket. The following devices were compared to the Macintosh laryngoscope, McGrath, Airtraq-SP, GlideScope, KingVision, C-MAC-D-Blade, AP Advance Difficult Airway Blade and Bonfils. The main outcome was first-attempt intubation success; secondary outcomes were intubation time, visibility on the screen, and view of the glottis. RESULTS The best intubation success rates were observed indoors asnd on the glacier under a blanket. The Macintosh performed better than the videolaryngoscopes under bright sunlight. We observed significant differences in the performance of devices with built-in screens under varying conditions. Wearing sunglasses improved performance with some but not all devices. Intubation times differed significantly between devices, regardless of the environmental condition (P<0.01). Screen visibility differed significantly between conditions and devices. CONCLUSION Successful intubation with videolaryngoscopes is less likely under bright sunlight conditions. The Macintosh laryngoscope performs better than videolaryngoscopes. Covering the heads of both the physician and the patient with a dark blanket sufficiently overcomes the detrimental effects of sunlight during intubation.