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.

Multidisciplinary guidance for safe tracheostomy care during the COVID-19 pandemic: the NHS National Patient Safety Improvement Programme (NatPatSIP)

The COVID-19 pandemic is causing a significant increase in the number of patients requiring relatively prolonged invasive mechanical ventilation and an associated surge in patients who need a tracheostomy to facilitate weaning from respiratory support. In parallel, there has been a global increase in guidance from professional bodies representing staff who care for patients with tracheostomies at different points in their acute hospital journey, rehabilitation and recovery. Of concern are the risks to healthcare staff of infection arising from tracheostomy insertion and caring for patients with a tracheostomy. Hospitals are also facing extraordinary demands on critical care services such that many patients who require a tracheostomy will be managed outside established intensive care or head and neck units and cared for by staff with little tracheostomy experience. These concerns led NHS England and NHS Improvement to expedite the National Patient Safety Improvement Programme's 'Safe Tracheostomy Care' workstream as part of the NHS COVID-19 response. Supporting this workstream, UK stakeholder organisations involved in tracheostomy care were invited to develop consensus guidance based on: expert opinion; the best available published literature; and existing multidisciplinary guidelines. Topics with direct relevance for frontline staff were identified. This consensus guidance includes: infectivity of patients with respect to tracheostomy indications and timing; aerosol-generating procedures and risks to staff; insertion procedures; and management following tracheostomy.

Consensus guidelines for managing the airway in patients with COVID-19: Guidelines from the Difficult Airway Society, the Association of Anaesthetists the Intensive Care Society, the Faculty of Intensive Care Medicine and the Royal College of Anaesthetists

Severe acute respiratory syndrome-corona virus-2, which causes coronavirus disease 2019 (COVID-19), is highly contagious. Airway management of patients with COVID-19 is high risk to staff and patients. We aimed to develop principles for airway management of patients with COVID-19 to encourage safe, accurate and swift performance. This consensus statement has been brought together at short notice to advise on airway management for patients with COVID-19, drawing on published literature and immediately available information from clinicians and experts. Recommendations on the prevention of contamination of healthcare workers, the choice of staff involved in airway management, the training required and the selection of equipment are discussed. The fundamental principles of airway management in these settings are described for: emergency tracheal intubation; predicted or unexpected difficult tracheal intubation; cardiac arrest; anaesthetic care; and tracheal extubation. We provide figures to support clinicians in safe airway management of patients with COVID-19. The advice in this document is designed to be adapted in line with local workplace policies.

The importance of prenatal 3-dimensional sonography in a case of a segmental overgrowth syndrome with unclear chromosomal microarray results

PIK3CA-related overgrowth spectrum, caused by mosaic mutations in the PIK3CA gene, is associated with regional or generalized asymmetric overgrowth of the body or a body part in addition to other clinical findings. Three-dimensional ultrasonography (3-D US) has the capability to display structural abnormalities in soft tissues or other organs, thereby facilitating identification of segmental overgrowth lesions. We present a case suspected of having a segmental overgrowth disorder based on 3-D US, whose chromosomal microarray result was abnormal, but apparently was not the cause of the majority of the fetus's clinical features.

Systematic review of benefits or harms of routine anaesthetist-inserted throat packs in adults: practice recommendations for inserting and counting throat packs: An evidence-based consensus statement by the Difficult Airway Society (DAS), the British Association of Oral and Maxillofacial Surgery (BAOMS) and the British Association of Otorhinolaryngology, Head and Neck Surgery (ENT-UK)

Throat packs are commonly inserted by anaesthetists after induction of anaesthesia for dental, maxillofacial, nasal or upper airway surgery. However, the evidence supporting this practice as routine is unclear, especially in the light of accidentally retained throat packs which constitute 'Never Events' as defined by NHS England. On behalf of three relevant national organisations, we therefore conducted a systematic review and literature search to assess the evidence base for benefit, and also the extent and severity of complications associated with throat pack use. Other than descriptions of how to insert throat packs in many standard texts, we could find no study that sought to assess the benefit of their insertion by anaesthetists. Instead, there were many reports of minor and major complications (the latter including serious postoperative airway obstruction and at least one death), and many descriptions of how to avoid complications. As a result of these findings, the three national organisations no longer recommend the routine insertion of throat packs by anaesthetists but advise caution and careful consideration. Two protocols for pack insertion are presented, should their use be judged necessary.

Guidelines for the management of tracheal intubation in critically ill adults

These guidelines describe a comprehensive strategy to optimize oxygenation, airway management, and tracheal intubation in critically ill patients, in all hospital locations. They are a direct response to the 4^th National Audit Project of the Royal College of Anaesthetists and Difficult Airway Society, which highlighted deficient management of these extremely vulnerable patients leading to major complications and avoidable deaths. They are founded on robust evidence where available, supplemented by expert consensus opinion where it is not. These guidelines recognize that improved outcomes of emergency airway management require closer attention to human factors, rather than simply introduction of new devices or improved technical proficiency. They stress the role of the airway team, a shared mental model, planning, and communication throughout airway management. The primacy of oxygenation including pre- and peroxygenation is emphasized. A modified rapid sequence approach is recommended. Optimal management is presented in an algorithm that combines Plans B and C, incorporating elements of the Vortex approach. To avoid delays and task fixation, the importance of limiting procedural attempts, promptly recognizing failure, and transitioning to the next algorithm step are emphasized. The guidelines recommend early use of a videolaryngoscope, with a screen visible to all, and second generation supraglottic airways for airway rescue. Recommendations for emergency front of neck airway are for a scalpel-bougie-tube technique while acknowledging the value of other techniques performed by trained experts. As most critical care airway catastrophes occur after intubation, from dislodged or blocked tubes, essential methods to avoid these complications are also emphasized.

Prenatal diagnosis of inverted duplication deletion 8p syndrome mimicking trisomy 18

Inverted duplication deletion of 8p (invdupdel[8p]) is a well-described and uncommon chromosomal rearrangement. The majority of the reported cases have revealed no life-threatening malformations. Although the invdupdel[8p] syndrome in children with central nervous system abnormalities has been reported before, we present the first prenatal microarray diagnosis of invdupdel[8p] syndrome mimicking trisomy 18 due to similar sonographic features. Contrary to reported cases with invdupdel[8p] syndrome, the present case had severe polyvalvular dysplasia and the infant deceased at day 12 of life. In this case, we also emphasize the diagnostic power of microarray analysis in detecting the underlying genetic causes for fetuses with multiple congenital anomalies. © 2017 Wiley Periodicals, Inc.

Difficult Airway Society Guidelines for the management of tracheal extubation

Tracheal extubation is a high-risk phase of anaesthesia. The majority of problems that occur during extubation and emergence are of a minor nature, but a small and significant number may result in injury or death. The need for a strategy incorporating extubation is mentioned in several international airway management guidelines, but the subject is not discussed in detail, and the emphasis has been on extubation of the patient with a difficult airway. The Difficult Airway Society has developed guidelines for the safe management of tracheal extubation in adult peri-operative practice. The guidelines discuss the problems arising during extubation and recovery and promote a strategic, stepwise approach to extubation. They emphasise the importance of planning and preparation, and include practical techniques for use in clinical practice and recommendations for post-extubation care.

The role of Plantaris Longus in Achilles tendinopathy: a biomechanical study

BACKGROUND

The Plantaris Longus Tendon (PLT) may be implicated in Achilles (AT) tendinopathy. Different mechanical characteristics may be the cause. This study is designed to measure these.

METHODS

Six PLT and six AT were harvested from frozen cadavers (aged 65-88). Samples were stretched to failure using a Minimat 2000™ (Rheometric Scientific Inc.). Force and elongation were recorded. Calculated tangent stiffness, failure stress and strain were obtained. Averaged mechanical properties were compared using paired, one-tailed t-tests.

RESULTS

Mean stiffness was higher (p<0.001) in the PLT, measuring 5.71 N/mm (4.68-6.64), compared with 1.73 N/mm (1.40-2.22) in AT. Failure stress was also higher (p<0.01) in PLT: 1.42 N/mm(2) (0.86-2.23) AT: 0.20 N/mm(2) (0.16-0.25). Failure strain was less (p<0.05) in PLT: 14.1% (11.5-16.8) than AT: 21.8% (14.9-37.9).

CONCLUSIONS

The PLT is stiffer, stronger than AT, demonstrating potential for relative movement under load. The stiffer PLT could tether AT and initiate an inflammatory response.

Deletion of glycogen synthase kinase-3β in cartilage results in up-regulation of glycogen synthase kinase-3α protein expression

The rate of endochondral bone growth determines final height in humans and is tightly controlled. Glycogen synthase kinase-3 (GSK-3) is a negative regulator of several signaling pathways that govern bone growth, such as insulin/IGF and Wnt/β-catenin. The two GSK-3 proteins, GSK-3α and GSK-3β, display both overlapping and distinct roles in different tissues. Here we show that pharmacological inhibition of GSK-3 signaling in a mouse tibia organ culture system results in enhanced bone growth, accompanied by increased proliferation of growth plate chondrocytes and faster turnover of hypertrophic cartilage to bone. GSK-3 inhibition rescues some, but not all, effects of phosphatidylinositide 3-kinase inhibition in this system, in agreement with the antagonistic role of these two kinases in response to signals such as IGF. However, cartilage-specific deletion of the Gsk3b gene in mice has minimal effects on skeletal growth or development. Molecular analyses demonstrated that compensatory up-regulation of GSK-3α protein levels in cartilage is the likely cause for this lack of effect. To our knowledge, this is the first tissue in which such a compensatory mechanism is described. Thus, our study provides important new insights into both skeletal development and the biology of GSK-3 proteins.

Low-skill fibreoptic intubation: use of the Aintree Catheter with the classic LMA

We describe a series of patients in whom anaesthetists - many of whom were trainees and had no prior experience of using the Aintree Intubation Catheter - successfully intubated the tracheas of patients in whom conventional attempts at intubation had failed. This was achieved by passing a fibrescope loaded with an Aintree Intubation Catheter through a classic Laryngeal Mask Airway (cLMA), which had already been placed to maintain the patient's airway.

Inhibition of nitric oxide synthase as a potential therapeutic target

Nitric oxide (NO) regulates numerous physiological processes, including neurotransmission, smooth muscle contractility, platelet reactivity, and the cytotoxic activity of immune cells. Because of the ubiquitous nature of NO, inappropriate release of this mediator has been linked to the pathogenesis of a number of disease states. This provides the rationale for the design of therapies that modulate NO concentrations selectively. A well-characterized family of compounds are the inhibitors of NO synthase, the enzyme responsible for the generation of NO; such agents are potentially beneficial in the treatment of conditions associated with an overproduction of NO, including septic shock, neurodegenerative disorders, and inflammation. This article provides an overview of NO synthase inhibitors, focusing on agents that prevent binding of substrate L-arginine.

Potassium supplementation in blacks with mild to moderate essential hypertension

Potassium chloride (KCl) salt (65 mmol) daily reduced BP from 153/104 to 146/101 mmHg in 32 hypertensive black females during a 6-week placebo controlled crossover study. The fall in BP was independent of the order of randomization and was significant for systolic (SBP; P less than 0.01) and diastolic (DBP; P less than 0.05) pressure after 4 weeks. Analysis of the 95% confidence intervals in this and in five other studies, two of which were reported as showing no beneficial effect, suggests that potassium supplementation does lower BP, but that the change is small and within the confidence levels of all six trials. Thus, apparent discrepancies in the literature are not genuine statistically.