Clinical tests for confirming tracheal intubation or excluding oesophageal intubation: a diagnostic test accuracy systematic review and meta-analysis.

Unrecognised oesophageal intubation causes preventable serious harm to patients undergoing tracheal intubation. When capnography is unavailable or doubted, clinicians still use clinical findings to confirm tracheal intubation, or exclude oesophageal intubation, and false reassurance from clinical examination is a recurring theme in fatal cases of unrecognised oesophageal intubation. We conducted a systematic review and meta-analysis of the diagnostic accuracy of five clinical examination tests and the oesophageal detector device when used to confirm tracheal intubation. We searched four databases for studies reporting index clinical tests against a reference standard, from inception to 28 February 2023. We included 49 studies involving 10,654 participants. Methodological quality was overall moderate to high. We looked at misting (three studies, 115 participants); lung auscultation (three studies, 217 participants); combined lung and epigastric auscultation (four studies, 506 participants); the oesophageal detector device (25 studies, 3024 participants); 'hang-up' (two non-human studies); and chest rise (one non-human study). The reference standards used were capnography (22 studies); direct vision (10 studies); and bronchoscopy (three studies). When used to confirm tracheal intubation, misting has a false positive rate (95%CI) of 0.69 (0.43-0.87); lung auscultation 0.14 (0.08-0.23); five-point auscultation 0.18 (0.08-0.36); and the oesophageal detector device 0.05 (0.02-0.09). Tests to exclude events that invariably lead to severe damage or death must have a negligible false positive rate. Misting or auscultation have too high a false positive rate to reliably exclude oesophageal intubation and there is insufficient evidence to support the use of 'hang-up' or chest rise. The oesophageal detector device may be considered where other more reliable means are not available, though waveform capnography remains the reference standard for confirmation of tracheal intubation.

Preventing unrecognised oesophageal intubation: a consensus guideline from the Project for Universal Management of Airways and international airway societies.

Across multiple disciplines undertaking airway management globally, preventable episodes of unrecognised oesophageal intubation result in profound hypoxaemia, brain injury and death. These events occur in the hands of both inexperienced and experienced practitioners. Current evidence shows that unrecognised oesophageal intubation occurs sufficiently frequently to be a major concern and to merit a co-ordinated approach to address it. Harm from unrecognised oesophageal intubation is avoidable through reducing the rate of oesophageal intubation, combined with prompt detection and immediate action when it occurs. The detection of 'sustained exhaled carbon dioxide' using waveform capnography is the mainstay for excluding oesophageal placement of an intended tracheal tube. Tube removal should be the default response when sustained exhaled carbon dioxide cannot be detected. If default tube removal is considered dangerous, urgent exclusion of oesophageal intubation using valid alternative techniques is indicated, in parallel with evaluation of other causes of inability to detect carbon dioxide. The tube should be removed if timely restoration of sustained exhaled carbon dioxide cannot be achieved. In addition to technical interventions, strategies are required to address cognitive biases and the deterioration of individual and team performance in stressful situations, to which all practitioners are vulnerable. These guidelines provide recommendations for preventing unrecognised oesophageal intubation that are relevant to all airway practitioners independent of geography, clinical location, discipline or patient type.

Project for Universal Management of Airways - part 1: concept and methods.

Multiple professional groups and societies worldwide have produced airway management guidelines. These are typically targeted at the process of tracheal intubation by a particular provider group in a restricted category of patients and reflect practice preferences in a particular geographical region. The existence of multiple distinct guidelines for some (but not other) closely related circumstances, increases complexity and may obscure the underlying principles that are common to all of them. This has the potential to increase cognitive load; promote the grouping of ideas in silos; impair teamwork; and ultimately compromise patient care. Development of a single set of airway management guidelines that can be applied across and beyond these domains may improve implementation; promote standardisation; and facilitate collaboration between airway practitioners from diverse backgrounds. A global multidisciplinary group of both airway operators and assistants was assembled. Over a 3-year period, a review of the existing airway guidelines and multiple reviews of the primary literature were combined with a structured process for determining expert consensus. Any discrepancies between these were analysed and reconciled. Where evidence in the literature was lacking, recommendations were made by expert consensus. Using the above process, a set of evidence-based airway management guidelines was developed in consultation with airway practitioners from a broad spectrum of disciplines and geographical locations. While consistent with the recommendations of the existing English language guidelines, these universal guidelines also incorporate the most recent concepts in airway management as well as statements on areas not widely addressed by the existing guidelines. The recommendations will be published in four parts that respectively address: airway evaluation; airway strategy; airway rescue and communication of airway outcomes. Together, these universal guidelines will provide a single, comprehensive approach to airway management that can be consistently applied by airway practitioners globally, independent of their clinical background or the circumstances in which airway management occurs.

Transtracheal jet ventilation in the 'can't intubate can't oxygenate' emergency: a systematic review.

BACKGROUND: Transtracheal jet ventilation (TTJV) is recommended in several airway guidelines as a potentially life-saving procedure during the 'Can't Intubate Can't Oxygenate' (CICO) emergency. Some studies have questioned its effectiveness. METHODS: Our goal was to determine the complication rates of TTJV in the CICO emergency compared with the emergency setting where CICO is not described (non-CICO emergency) or elective surgical setting. Several databases of published and unpublished literature were searched systematically for studies describing TTJV in human subjects. Complications were categorized as device failure, barotrauma (including subcutaneous emphysema), and miscellaneous. Device failure was defined by the inability to place and/or use the TTJV device, not patient survival. RESULTS: Forty-four studies (428 procedures) met the inclusion criteria. Four studies included both emergency and elective procedures. Thirty studies described 132 emergency TTJV procedures; 90 were CICO emergencies. Eighteen studies described 296 elective TTJV procedures. Device failure occurred in 42% of CICO emergency vs 0% of non-CICO emergency (P<0.001) and 0.3% of elective procedures (P<0.001). Barotrauma occurred in 32% of CICO emergency vs 7% of non-CICO emergency (P<0.001) and 8% of elective procedures (P<0.001). The total number of procedures with any complication was 51% of CICO emergency vs 7% of non-CICO emergency (P<0.001) and 8% of elective procedures (P<0.001). Several reports described TTJV-related subcutaneous emphysema hampering subsequent attempts at surgical airway or tracheal intubation. CONCLUSIONS: TTJV is associated with a high risk of device failure and barotrauma in the CICO emergency. Guidelines and recommendations supporting the use of TTJV in CICO should be reconsidered.

The McGrath® Series 5 videolaryngoscope vs the Macintosh laryngoscope: a randomised, controlled trial in patients with a simulated difficult airway.

We compared the McGrath® Series 5 videolaryngoscope with the Macintosh laryngoscope in a simulated difficult airway, using manual in-line stabilisation in 88 anaesthestised patients of ASA physical status 1-2. The primary outcome was laryngoscopic view. Secondary outcomes included rates of successful tracheal intubation and complications. A Cormack and Lehane grade-1 or -2 view was found in all patients when using the McGrath compared with 45 (51%, p < 0.0001) using the Macintosh laryngoscopes. The mean (SD) percentage of glottic opening was 82 (23)% using the McGrath compared with 13 (23)% using the Macintosh (p < 0.0001). In 66 out of 88 patients (75%), the McGrath improved the glottic view by one to three grades compared with the Macintosh (p < 0.001). Intubation of the trachea was successful in all patients using the McGrath, while the Macintosh was successful in 26 (59%, p < 0.001). There was no significant difference in the complication rates between the devices.

Efficacy of high-fidelity simulation debriefing on the performance of practicing anaesthetists in simulated scenarios.

BACKGROUND: Research into adverse events in hospitalized patients suggests that a significant number are preventable. The purpose of this randomized, controlled study was to determine if simulation-based debriefing improved performance of practicing anaesthetists managing high-fidelity simulation scenarios. METHODS: The anaesthetists were randomly allocated to Group A: simulation debriefing; Group B: home study; and Group C: no intervention and secondary randomization to one of two scenarios. Six to nine months later, subjects returned to manage the alternate scenario. Facilitators blinded to study group allocation completed the performance checklists (dichotomously scored checklist, DSC) and Global Rating Scale of Performance (GRS). Two non-expert raters were trained, and assessed all videotaped performances. RESULTS: Interim analysis indicated no difference between Groups B and C which were merged into one group. Seventy-four subjects were recruited, with 58 complete data sets available. There was no significant effect of group on pre-test scores. A significant improvement was seen between pre- and post-tests on the DSC in debriefed subjects (pre-test 66.8%, post-test 70.3%; F(1,57)=4.18, P=0.046). Both groups showed significant improvement in the GRS over time (F(1,57)=5.94, P=0.018), but no significant difference between the groups. CONCLUSIONS: We found a modest improvement in performance on a DSC in the debriefed group and overall improvement in both control and debriefed groups using a GRS. Whether this improvement translates into clinical practice has yet to be determined.

Tracheal intubation using Bullard laryngoscope for patients with a simulated difficult airway.

PURPOSE: To evaluate the utility and safety of orotracheal intubation in adult patients with simulated difficult airways using the Bullard Laryngoscope (BL). METHODS: A rigid cervical collar was used to simulate the difficult airway. The study consisted of two phases. Phase I evaluated the BL used in conjunction with an independently styletted endotracheal tube (ISETT) passed freehand into the trachea. Phase II evaluated the new Multifunctional Intubating Stylet (MFIS). Forty patients were studied in each phase. Following induction of anesthesia a rigid cervical collar was applied and the laryngoscopic grade assessed. Tracheal intubation was then performed using the BL with either an ISETT or the MFIS. The total time to intubate, number of attempts, failures, hemodynamic changes during intubation were recorded. RESULTS: The rigid collar effectively simulated a difficult laryngoscopy, 65% of patients had a grade 3 view. The success rates for tracheal intubation using the ISETT and MFIS were 88% and 83% respectively. The average times to intubation were similar for both intubating techniques (45.4 +/- 26.8 sec for the ISETT and 41.2 +/- 25.2 sec for the MFIS). Although there were minor hemodynamic changes, mucosal bleeding and sore throat following intubation, there were no major complications in any of the study patients. CONCLUSIONS: The BL, used with either an ISETT or the MFIS, is an effective and safe intubating device for patients with simulated restricted cervical spine movement. Further studies are needed to compare the effectiveness and safety of these two techniques in managing patients with a difficult airway.

ABO blood group and susceptibility to gonococcal infection. I. Factors affecting phagocytosis of Neisseria gonorrhoeae.

The effect of opsonization of Neisseria gonorrhoeae by isohaemagglutinins from normal serum on attachment to human polymorphonuclear leukocytes (PMN) was investigated. No significant differences between sera from blood groups O, A, B or AB were found. Differences in attachment of gonococci were related to differences in lipopolysaccharide detected by sensitivity to R-type pyocines of Pseudomonas aeruginosa. Non-pilate variants of each test strain markedly stimulated nitroblue tetrazolium (NBT) reduction in PMN, but their pilate variants were essentially inactive in the NBT test.