Flexible bronchoscopic intubation through a supraglottic airway device: An evaluation of consultant anaesthetist performance.

BACKGROUND: Few clinical studies investigate technical skill performance in experienced clinicians. METHODS: We undertook a prospective observational study evaluating procedural skill competence in consultant anaesthetists who performed flexible bronchoscopic intubation (FBI) under continuous ventilation through a second-generation supraglottic airway device (SAD). Airway management was recorded on video and performance evaluated independently by three external assessors. We included 100 adult patients undergoing airway management by 25 anaesthetist specialists, each performing four intubations. We used an Objective Structured Assessment of Technical Skills-inspired global rating scale as primary outcome. Further, we assessed the overall pass rate (proportion of cases where the average of assessors' evaluation for every domain scored ≥3); the progression in the global rating scale score; time to intubation; self-reported procedural confidence; and pass rate from the first to the fourth airway procedure. RESULTS: Overall median global rating scale score was 29.7 (interquartile range 26.0-32.7 [range 16.7-37.7]. At least one global rating scale domain was deemed 'not competent' (one or more domains in the evaluation was scored <3) in 30% of cases of airway management, thus the pass rate was 70% (95% CI 60%-78%). After adjusting for multiple testing, we found a statistically significant difference between the first and fourth case of airway management regarding time to intubation (p = .006), but no difference in global rating scale score (p = .018); self-reported confidence before the procedure (p = .014); or pass rate (p = .109). CONCLUSION: Consultant anaesthetists had a median global rating scale score of 29.7 when using a SAD as conduit for FBI. However, despite reporting high procedural confidence, at least one global rating scale domain was deemed 'not competent' in 30% of cases, which indicates a clear potential for improvement of skill competence among professionals.

Implementation of video laryngoscopes and the development in airway management strategy and prevalence of difficult tracheal intubation: A national cohort study.

BACKGROUND: We aimed to determine the development in the use of video laryngoscopy over a 9-year period, and its possible impact on airway planning and management. METHODS: We retrieved 822,259 records of tracheal intubations recorded from 2008 to 2016 in the Danish Anaesthesia Database. The circumstances regarding pre-operative airway assessment, the scheduled airway management plan and the actual airway management concerning video laryngoscopy were reported for each year of observation. Further, the association between year of observation and various airway management related outcomes was evaluated by multivariate logistic regression. RESULTS: There was a significant increase in airway management with 'advanced technique successfully used within two attempts' from 2.7% in 2008 to 15.5% in 2016 (p < .0001). This predominantly reflects use of video laryngoscopy. The prevalence of tracheal intubations 'scheduled for video laryngoscopy' increased from 3.5% in 2008 to 10.6% in 2016 (p < .0001). We found a significant increase in the prevalence of anticipated difficulties with intubations by direct laryngoscopy from 1.8% in 2008 to 5.2% in 2016 (p < .0001). The prevalence of failed tracheal intubations decreased from 0.14% in 2008 to 0.05% in 2016 (p < .0001). CONCLUSION: From 2008 to 2016, a period of massive implementation of video laryngoscopes, a significant change in airway management behaviour was recorded. Increasingly, video laryngoscopy is becoming a first-choice device for both acute and routine airway management. Most importantly, the data showed a noticeable reduction in failed intubation over the time of observation.

AuraGain™ versus i-gel™ for bronchoscopic intubation under continuous oxygenation: A randomised controlled trial.

INTRODUCTION: After failed mask ventilation and tracheal intubation, guidelines issued by the Difficult Airway Society recommend placing a second generation supraglottic airway device to secure oxygenation. Ultimately, a secure airway can be obtained by tracheal intubation through the supraglottic airway device using a bronchoscope. In this randomised trial, we compared the AuraGain™ with the i-gel™ as conduit for bronchoscopic intubation under continuous oxygenation performed by a group of anaesthesiologists with variable experience in a general population of patients. METHOD: We randomised one hundred patients who were equally allocated to flexible bronchoscopic intubation through the i-gel™ or the AuraGain™. In a random order, 25 anaesthesiologists each performed four intubations, two using the i-gel™ and two using the AuraGain™. Our primary outcome was 'total time for airway management'; i.e. total time from manually reaching the SAD to successful FBI confirmed at the end of the first inspiratory downstroke on the capnography curve. RESULTS: In total, 87% (95% CI, 79%-92%) of the patients were successfully intubated through the allocated supraglottic airway device. There was no difference in total time for airway management between the i-gel™ and the AuraGain™ (199 vs. 227 s, p = .076). However, there was a difference in time for placement of the i-gel™, compared to the AuraGain™, (37 vs. 54 s, p < .001). There were nine failed intubations in the AuraGain™ group compared to four in the i-gel™ group (p = .147). CONCLUSION: We found no difference in total time for airway management between using the i-gel™ and using the AuraGain™.

Anesthesiologists' airway management expertise: Identifying subjective and objective knowledge gaps.

BACKGROUND: Failure in airway management continues to cause preventable patient harm, and the recommended continuing education is challenged by anesthesiologists' unknown knowledge gaps. This study aimed to identify anesthesiologists' subjective and objective knowledge gaps as well as areas where anesthesiologists are incorrect and unaware. METHODS: An adaptive E-learning program with 103 questions on adult airway management was used for subjective and objective assessment of anesthesiologists' knowledge. All anesthesiologists in the Capital Region of Denmark were invited to participate. RESULTS: The response rate was 67% (191/285). For preoperative planning, participants stated low confidence (subjective assessment) regarding predictors of difficult airway management in particular (69.1%-79.1%). Test scores (objective assessment) were lowest for obstructive sleep apnea as a predictor of difficult airway management (28.8% correct), with participants being incorrect and unaware in 33.5% of the answers. For optimization of basic techniques, the lowest confidence ratings related to patient positioning and prediction of difficulties (57.4%-83.2%), which agreed with the lowest test scores. Concerning advanced techniques, videolaryngoscopy prompted the lowest confidence (72.4%-85.9%), while emergency cricothyrotomy resulted in the lowest test scores (47.4%-67.8%). Subjective and objective assessments correlated and lower confidence was associated with lower test scores: preoperative planning [r = -.58, P < .001], optimization of basic techniques [r = -.58, P = .002], and advanced techniques [r = -.71, P < .001]. CONCLUSION: We identified knowledge gaps in important areas of adult airway management with differing findings from the subjective and objective assessments. This underlines the importance of objective assessment to guide continuing education.

Intraindividual variation of the transversus abdominis plane block: an exploratory study in healthy volunteers.

INTRODUCTION: The transversus abdominis plane block is widely used in postoperative pain management after abdominal surgery. However, large interindividual variation in the cutaneous distribution area of the block has been demonstrated. The purpose of the present study was to explore the reproducibility of the block by determining the intraindividual variation when repeating the block on two separate days. METHODS: Ultrasound-guided posterior transversus abdominis plane blocks were performed in 16 healthy volunteers and repeated after at least 2 days. Cutaneous sensory block areas and distributions, thresholds for mechanical stimulation, abdominal muscle thicknesses at rest and during maximal contraction, waist circumferences and block duration times were measured on both days. Outcome measurements from the 2 days were compared using a one-sample t-test and intraclass correlation coefficients were calculated for each parameter. Agreement was evaluated visually using Bland-Altman plots. RESULTS: None of the mean values of the outcome measurements differed significantly between the 2 days. Intraclass correlation coefficient was 0.75 (moderate-to-good reliability) for lateral abdominal muscle thickness during maximal contraction, but ranges from -0.07 to 0.67 were found for all other outcome measurements (poor-to-moderate reliability). CONCLUSION: We found a moderate-to-good reproducibility for lateral abdominal muscle thickness during maximal voluntary contraction, but a moderate-to-poor reproducibility for all other block characteristics. However, the cutaneous distribution of the block was still located primarily inferior to a horizontal line through the umbilicus and lateral relative to a vertical line through the anterior superior iliac spine.

"Eyeball test" of thermographic patterns for predicting a successful lateral infraclavicular block.

PURPOSE: Increased distal skin temperature can be used to predict the success of lateral infraclavicular (LIC) block. We hypothesized that an "eyeball test" of specific infrared thermographic patterns after LIC block could be used to determine block success. METHODS: In this observational study, five observers trained in four distinct thermographic patterns independently evaluated thermographic images of the hands of 40 patients at baseline and at one-minute intervals for 30 min after a LIC block. Sensitivity, specificity, and predictive values of a positive and a negative test were estimated to evaluate the validity of specific thermographic patterns for predicting a successful block. Sensory and motor block of the musculocutaneous, radial, ulnar, and median nerves defined block success. Fleiss' kappa statistics of multiple interobserver agreements were used to evaluate reliability. RESULTS: As a diagnostic test, the defined specific thermographic patterns of the hand predicted a successful block with increasing accuracy over the 30-min observation period. Block success was predicted with a sensitivity of 92.4% (95% confidence interval [CI], 86.8 to 96.2) and with a specificity of 84.0% (95% CI, 70.3 to 92.4) at min 30. The Fleiss' kappa for the five observers was 0.87 (95% CI, 0.77 to 0.96). CONCLUSION: We conclude that visual evaluation by an eyeball test of specific thermographic patterns of the blocked hands may be useful as a valid and reliable diagnostic test for predicting a successful LIC block.

Avoidance versus use of neuromuscular blocking agents for improving conditions during tracheal intubation or direct laryngoscopy in adults and adolescents.

BACKGROUND: Tracheal intubation during induction of general anaesthesia is a vital procedure performed to secure a patient's airway. Several studies have identified difficult tracheal intubation (DTI) or failed tracheal intubation as one of the major contributors to anaesthesia-related mortality and morbidity. Use of neuromuscular blocking agents (NMBA) to facilitate tracheal intubation is a widely accepted practice. However, because of adverse effects, NMBA may be undesirable. Cohort studies have indicated that avoiding NMBA is an independent risk factor for difficult and failed tracheal intubation. However, no systematic review of randomized trials has evaluated conditions for tracheal intubation, possible adverse effects, and postoperative discomfort. OBJECTIVES: To evaluate the effects of avoiding neuromuscular blocking agents (NMBA) versus using NMBA on difficult tracheal intubation (DTI) for adults and adolescents allocated to tracheal intubation with direct laryngoscopy. To look at various outcomes, conduct subgroup and sensitivity analyses, examine the role of bias, and apply trial sequential analysis (TSA) to examine the level of available evidence for this intervention. SEARCH METHODS: We searched CENTRAL, MEDLINE, Embase, BIOSIS, International Web of Science, LILACS, advanced Google, CINAHL, and the following trial registries: Current Controlled Trials; ClinicalTrials.gov; and www.centerwatch.com, up to January 2017. We checked the reference lists of included trials and reviews to look for unidentified trials. SELECTION CRITERIA: We included randomized controlled trials (RCTs) that compared the effects of avoiding versus using NMBA in participants 14 years of age or older. DATA COLLECTION AND ANALYSIS: Two review authors extracted data independently. We conducted random-effects and fixed-effect meta-analyses and calculated risk ratios (RRs) and their 95% confidence intervals (CIs). We used published data and data obtained by contacting trial authors. To minimize the risk of systematic error, we assessed the risk of bias of included trials. To reduce the risk of random errors caused by sparse data and repetitive updating of cumulative meta-analyses, we applied TSA. MAIN RESULTS: We identified 34 RCTs with 3565 participants that met our inclusion criteria. All trials reported on conditions for tracheal intubation; seven trials with 846 participants described 'events of upper airway discomfort or injury', and 13 trials with 1308 participants reported on direct laryngoscopy. All trials used a parallel design. We identified 18 dose-finding studies that included more interventions or control groups or both. All trials except three included only American Society of Anesthesiologists (ASA) class I and II participants, 25 trials excluded participants with anticipated DTI, and obesity or overweight was an excluding factor in 13 studies. Eighteen trials used suxamethonium, and 18 trials used non-depolarizing NMBA.Trials with an overall low risk of bias reported significantly increased risk of DTI with no use of NMBA (random-effects model) (RR 13.27, 95% CI 8.19 to 21.49; P < 0.00001; 508 participants; four trials; number needed to treat for an additional harmful outcome (NNTH) = 1.9, I2 = 0%, D2 = 0%, GRADE = moderate). The TSA-adjusted CI for the RR was 1.85 to 95.04. Inclusion of all trials resulted in confirmation of results and of significantly increased risk of DTI when an NMBA was avoided (random-effects model) (RR 5.00, 95% CI 3.49 to 7.15; P < 0.00001; 3565 participants; 34 trials; NNTH = 6.3, I2 = 70%, D2 = 82%, GRADE = low). Again the cumulative z-curve crossed the TSA monitoring boundary, demonstrating harmful effects of avoiding NMBA on the proportion of DTI with minimal risk of random error. We categorized only one trial reporting on upper airway discomfort or injury as having overall low risk of bias. Inclusion of all trials revealed significant risk of upper airway discomfort or injury when an NMBA was avoided (random-effects model) (RR 1.37, 95% CI 1.09 to 1.74; P = 0.008; 846 participants; seven trials; NNTH = 9.1, I2 = 13%, GRADE = moderate). The TSA-adjusted CI for the RR was 1.00 to 1.85. None of these trials reported mortality. In terms of our secondary outcome 'difficult laryngoscopy', we categorized only one trial as having overall low risk of bias. All trials avoiding NMBA were significantly associated with difficult laryngoscopy (random-effects model) (RR 2.54, 95% CI 1.53 to 4.21; P = 0.0003; 1308 participants; 13 trials; NNTH = 25.6, I2 = 0%, D2= 0%, GRADE = low); however, TSA showed that only 6% of the information size required to detect or reject a 20% relative risk reduction (RRR) was accrued, and the trial sequential monitoring boundary was not crossed. AUTHORS' CONCLUSIONS: This review supports that use of an NMBA may create the best conditions for tracheal intubation and may reduce the risk of upper airway discomfort or injury following tracheal intubation. Study results were characterized by indirectness, heterogeneity, and high or uncertain risk of bias concerning our primary outcome describing difficult tracheal intubation. Therefore, we categorized the GRADE classification of quality of evidence as moderate to low. In light of defined outcomes of individual included trials, our primary outcomes may not reflect a situation that many clinicians consider to be an actual difficult tracheal intubation by which the patient's life or health may be threatened.

Lack of national consensus in preoperative airway assessment.

INTRODUCTION: Difficult airway management is associated with an increased risk of morbidity and mortality. Several preoperative risk factors associated with airway management difficulties have been proposed; however, no clear guideline for airway assessments exists. We therefore hypothesised that Danish airway assessment was lacking uniformity. We aimed to examine whether multivariable risk assessment tools and predictors for difficult intubation and mask ventilation were used systematically. METHODS: Heads of anaesthesia departments were sent a six-question survey at the beginning of 2012. We asked if systematic risk assessment tools, particularly the Simplified Airway Risk Index (SARI), and predictors for difficult intubation and mask ventilation were used. Additionally, we asked if any risk factors were pre-printed on the anaesthesia record. RESULTS: In all, 29 of 31 (94%) departments responded. The SARI was implemented in 8 of 29 (28%, 95% confidence interval (CI): 15-46%) departments with major regional differences. There was no significant association between using the SARI and a reduced number of unanticipated difficult intubation (p = 0.06). Mallampati classification (95.2%, 95% CI: 77.3-99.2%), history of airway management difficulties (85.7%, 95% CI: 65.4-95.0%), ability to prognath (81.0%, 95% CI: 60.0-92.3%) and neck mobility (81.0%, 95% CI: 60.0-92.3%) were the main predictors registered. CONCLUSION: We found considerable inter-departmental variance in the standards employed for airway assessment and no uniform pattern in the registration of risk factors for airway management difficulties. Better prediction of difficult intubation could not be detected in departments that used the SARI. FUNDING: none. TRIAL REGISTRATION: not relevant.

Risk Factors for and Prediction of a Difficult Neuraxial Block: A Cohort Study of 73,579 Patients from the Danish Anaesthesia Database.

BACKGROUND: A difficult neuraxial block (DNB) may be associated with complications. The aims of this study were to estimate the prevalence of DNB, assess patient-related and organizational factors associated with DNB, and evaluate the diagnostic accuracy of an accumulated risk score for predicting DNB. METHODS: A consecutive cohort of 73,579 patients was retrieved. A predefined DNB score and information on patient-related and organizational factors were included in the analyses. Logistic regression analysis was performed. We evaluated the diagnostic accuracy of an accumulated weighted point score of the patient-related risk factors of DNB. RESULTS: The prevalence of DNB and abandoned neuraxial block was 3.9 (95% confidence interval [95% CI], 3.7-4.0) and 0.2 (95% CI, 0.16-0.22), respectively. Body mass index of 35 or higher and previous DNB were associated with DNB, with 3.23 (95% CI, 2.87-3.65) and 2.00 (95% CI, 1.33-3.00), respectively. However, the remaining patient-related covariates were associated with DNB with substantial lower odds ratios. The diagnostic accuracy of an accumulated sum score demonstrated an area under the curve of 0.62 (95% CI, 0.61-0.64), a positive predictive value of 5%, and a positive likelihood ratio of 1.4. CONCLUSIONS: Despite of strong statistical association between DNB and the tested risk factors, the low odds ratios and estimates of the diagnostic test indicate that the clinical impact using an accumulated risk sum score is limited.

Cutaneous Sensory Block Area, Muscle-Relaxing Effect, and Block Duration of the Transversus Abdominis Plane Block: A Randomized, Blinded, and Placebo-Controlled Study in Healthy Volunteers.

BACKGROUND AND OBJECTIVES: The transversus abdominis plane (TAP) block is a widely used nerve block. However, basic block characteristics are poorly described. The purpose of this study was to assess the cutaneous sensory block area, muscle-relaxing effect, and block duration. METHODS: Sixteen healthy volunteers were randomized to receive an ultrasound-guided unilateral TAP block with 20 mL 7.5 mg/mL ropivacaine and placebo on the contralateral side. Measurements were performed at baseline and 90 minutes after performing the block. Cutaneous sensory block area was mapped and separated into a medial and lateral part by a vertical line through the anterior superior iliac spine. We measured muscle thickness of the 3 lateral abdominal muscle layers with ultrasound in the relaxed state and during maximal voluntary muscle contraction. The volunteers reported the duration of the sensory block and the abdominal muscle-relaxing effect. RESULTS: The lateral part of the cutaneous sensory block area was a median of 266 cm2 (interquartile range, 191-310 cm2) and the medial part 76 cm 2(interquartile range, 54-127 cm2). In all the volunteers, lateral wall muscle thickness decreased significantly by 9.2 mm (6.9-15.7 mm) during a maximal contraction. Sensory block and muscle-relaxing effect duration were 570 minutes (512-716 minutes) and 609 minutes (490-724 minutes), respectively. CONCLUSIONS: Cutaneous sensory block area of the TAP block is predominantly located lateral to a vertical line through the anterior superior iliac spine. The distribution is nondermatomal and does not cross the midline. The muscle-relaxing effect is significant and consistent. The block duration is approximately 10 hours with large variation.

Tracheal intubation with a flexible fibreoptic scope or the McGrath videolaryngoscope in simulated difficult airway scenarios: a randomised controlled manikin study.

BACKGROUND: Flexible fibreoptic endoscopic (FFE) intubation is considered the 'gold-standard' when difficult airway management is anticipated. Several videolaryngoscopes have been developed to facilitate intubation by laryngoscopy. OBJECTIVE: The aim of the study was to compare the performance of the McGrath series 5 videolaryngoscope (McGrath videolaryngoscope) and the FFE for tracheal intubation in manikins with a simulated difficult airway, hypothesizing that the McGrath videolaryngoscope intubation would prove faster than FFE intubation. DESIGN: A randomised controlled study. SETTING: The Danish Institute for medical simulation between December 2009 and June 2010. PARTICIPANTS: Twenty-eight anaesthesia residents participating in the Danish mandatory 3-day airway management course. INTERVENTIONS: All participants received instructions and training in the use of the McGrath videolaryngoscope and FFE. The participants then performed tracheal intubation on a SimMan manikin once with the McGrath videolaryngoscope and once with the FFE in three difficult airway scenarios: (1) pharyngeal obstruction; (2) pharyngeal obstruction and cervical rigidity; (3) tongue oedema. MAIN OUTCOME MEASURES: We measured successful intubations, defined as intubation within 120  s, and time to tracheal intubation. RESULTS: The trachea was intubated within 120  s with the McGrath videolaryngoscope in 25 out of 27 (93%), 25 out of 28 (89%) and 18 out of 28 (64%) occasions compared with 11 out of 28 (40%), 11 out of 28 (40%) and 16 out of 28 (57%) with the FFE in scenarios (1), (2) and (3), respectively. Time to tracheal intubation was shorter with the McGrath videolaryngoscope in scenarios (1) and (2) than with the FFE (Wilcoxon signed rank sum test, P < 0.0001). CONCLUSION: The McGrath videolaryngoscope is a valuable device with higher success rate and a quicker performance in simulated difficult airways. In patients, videolaryngoscopy may have a role in difficult airway algorithms, but the optimal device has yet to be found.

Awake fiberoptic or awake video laryngoscopic tracheal intubation in patients with anticipated difficult airway management: a randomized clinical trial.

BACKGROUND: Awake flexible fiberoptic intubation (FFI) is the gold standard for management of anticipated difficult tracheal intubation. The purpose of this study was to compare awake FFI to awake McGrath® video laryngoscope, (MVL), (Aircraft Medical, Edinburgh, Scotland, United Kingdom) intubation in patients with an anticipated difficult intubation. The authors examined the hypothesis that MVL intubation would be faster than FFI. METHODS: Ninety-three adult patients with anticipated difficult intubation were randomly allocated to awake FFI or awake MVL, patients were given glycopyrrolate, nasal oxygen, topical lidocaine orally, and a transtracheal injection of 100 mg lidocaine. Remifentanil infusion was administered intravenously to a Ramsay sedation score of 2-4. Time to tracheal intubation was recorded by independent assessors. The authors also recorded intubation success on the first attempt, investigators' evaluation of ease of the technique, and patients reported intubation-discomfort evaluated on a visual analog scale. RESULTS: Eighty-four patients were eligible for analysis. Time to tracheal intubation was median [interquartile range, IQR] 80 s [IQR 58-117] with FFI and 62 s [IQR 55-109] with MVL (P = 0.17). Intubation success on the first attempt was 79% versus 71% for FFI and MVL, respectively. The median visual analog scale score for ease of intubation was 2 (IQR 1-4) versus 1 (IQR 1-6) for FFI and MVL, respectively. The median visual analog scale score for patients' assessment of discomfort for both techniques was 2, FFI (IQR 0-3), MVL (IQR 0-4). CONCLUSIONS: The authors found no difference in time to tracheal intubation between awake FFI and awake MVL intubation performed by experienced anesthesiologists in patients with anticipated difficult airway.