Implementing human factors in anaesthesia: guidance for clinicians, departments and hospitals: Guidelines from the Difficult Airway Society and the Association of Anaesthetists: Guidelines from the Difficult Airway Society and the Association of Anaesthetists.

Human factors is an evidence-based scientific discipline used in safety critical industries to improve safety and worker well-being. The implementation of human factors strategies in anaesthesia has the potential to reduce the reliance on exceptional personal and team performance to provide safe and high-quality patient care. To encourage the adoption of human factors science in anaesthesia, the Difficult Airway Society and the Association of Anaesthetists established a Working Party, including anaesthetists and operating theatre team members with human factors expertise and/or interest, plus a human factors scientist, an industrial psychologist and an experimental psychologist/implementation scientist. A three-stage Delphi process was used to formulate a set of 12 recommendations: these are described using a 'hierarchy of controls' model and classified into design, barriers, mitigations and education and training strategies. Although most anaesthetic knowledge of human factors concerns non-technical skills, such as teamwork and communication, human factors is a broad-based scientific discipline with many other additional aspects that are just as important. Indeed, the human factors strategies most likely to have the greatest impact are those related to the design of safe working environments, equipment and systems. While our recommendations are primarily provided for anaesthetists and the teams they work with, there are likely to be lessons for others working in healthcare beyond the speciality of anaesthesia.

Human factors in anaesthesia: a narrative review.

Healthcare relies on high levels of human performance, as described by the 'human as the hero' concept. However, human performance varies and is recognised to fall in high-pressure situations, meaning that it is not a reliable method of ensuring safety. Other safety-critical industries embed human factors principles into all aspects of their organisations to improve safety and reduce reliance on exceptional human performance; there is potential to do the same in anaesthesia. Human factors is a broad-based scientific discipline which aims to make it as easy as possible for workers to do things correctly. The human factors strategies most likely to be effective are those which 'design out' the chance of an error or adverse event occurring. When errors or adverse events do happen, barriers are in place to trap them and reduce the risk of progression to patient and/or worker harm. If errors or adverse events are not trapped by these barriers, mitigations are in place to minimise the consequences. Non-technical skills form an important part of human factors barriers and mitigation strategies and include: situation awareness; decision-making; task management; and team working. Human factors principles are not a substitute for proper investment and appropriate staffing levels. Although applying human factors science has the potential to save money in the long term, its proper implementation may require investment before reward can be reaped. This narrative review describes what is known about human factors in anaesthesia to date.

Human factors in preventing complications in anaesthesia: a systematic review.

Human factors in anaesthesia were first highlighted by the publication of the Anaesthetists Non-Technical Skills Framework, and since then an awareness of their importance has gradually resulted in changes in routine clinical practice. This review examines recent literature around human factors in anaesthesia, and highlights recent national reports and guidelines with a focus on team working, communication, situation awareness and human error. We highlight the importance of human factors in modern anaesthetic practice, using the example of complex trauma.

Systematic review of the anaesthetic management of non-iatrogenic acute adult airway trauma.

INTRODUCTION: Non-iatrogenic trauma to the airway is rare and presents a significant challenge to the anaesthetist. Although guidelines for the management of the unanticipated difficult airway have been published, these do not make provision for the 'anticipated' difficult airway. This systematic review aims to inform best practice and suggest management options for different injury patterns. METHODS: A literature search was conducted using Embase, Medline, and Google Scholar for papers after the year 2000 reporting on the acute airway management of adult patients who suffered airway trauma. Our protocol and search strategy are registered with and published by PROSPERO (http://www.crd.york.ac.uk/PROSPERO, ID: CRD42016032763). RESULTS: A systematic literature search yielded 578 articles, of which a total of 148 full-text papers were reviewed. We present our results categorized by mechanism of injury: blunt, penetrating, blast, and burns. CONCLUSIONS: The hallmark of airway management with trauma to the airway is the maintenance of spontaneous ventilation, intubation under direct vision to avoid the creation of a false passage, and the avoidance of both intermittent positive pressure ventilation and cricoid pressure (the latter for laryngotracheal trauma only) during a rapid sequence induction. Management depends on available resources and time to perform airway assessment, investigations, and intervention (patients will be classified into one of three categories: no time, some time, or adequate time). Human factors, particularly the development of a shared mental model amongst the trauma team, are vital to mitigate risk and improve patient safety.

Emergency front of neck access in the management of acute airway obstruction secondary to postoperative neck haematoma.

Airway compromise is the most significant complication of a postoperative neck haematoma. Here, we report the management of a case of complete airway obstruction secondary to an acute neck haematoma arising after radical neck dissection, partial glossectomy and a free flap reconstruction. The patient deteriorated precipitously and required immediate emergency surgical front of neck access to secure the airway. Drawing on our experience of this case, we propose a mental model to inform the emergency airway management of postoperative neck haematoma following all types of surgery.

The Difficult Airway Society 'ADEPT' guidance on selecting airway devices: the basis of a strategy for equipment evaluation.

Faced with the concern that an increasing number of airway management devices were being introduced into clinical practice with little or no prior evidence of their clinical efficacy or safety, the Difficult Airway Society formed a working party (Airway Device Evaluation Project Team) to establish a process by which the airway management community within the profession could itself lead a process of formal device/equipment evaluation. Although there are several national and international regulations governing which products can come on to the market and be legitimately sold, there has hitherto been no formal professional guidance relating to how products should be selected (i.e. purchased). The Airway Device Evaluation Project Team's first task was to formulate such advice, emphasising evidence-based principles. Team discussions led to a definition of the minimum level of evidence needed to make a pragmatic decision about the purchase or selection of an airway device. The Team concluded that this definition should form the basis of a professional standard, guiding those with responsibility for selecting airway devices. We describe how widespread adoption of this professional standard can act as a driver to create an infrastructure in which the required evidence can be obtained. Essential elements are that: (i) the Difficult Airway Society facilitates a coherent national network of research-active units; and (ii) individual anaesthetists in hospital trusts play a more active role in local purchasing decisions, applying the relevant evidence and communicating their purchasing decisions to the Difficult Airway Society.

Factors contributing to delayed decannulation of temporary tracheostomies following free tissue reconstructive surgery for head and neck cancer.

Temporary tracheostomies (TT) are performed to secure the airway perioperatively and postoperatively in head and neck cancer patients undergoing tumour resection and free tissue reconstructive surgery. Patients report that having a TT is unpleasant and they appreciate its removal at the earliest opportunity. Early removal not only improves patient satisfaction but should allow for a more rapid recovery. The aim of this prospective study was to assess factors that contribute to delays in decannulation following TT and hence to provide an insight into the factors that will support earlier decannulation when it is safe to do so. Consecutive patients who had TT over a six-month period were included. Delayed decannulation was defined as that after day seven postoperatively. There were 42 patients with a median (IQR) age of 70 (60-74) years, 26 of whom were men. The tracheostomy was surgical in 29 and percutaneous in 13. The median (IQR) time to decannulation was 4 (3-5) days (range 1-11 days). Seven patients had delayed removal (7-11 days), the reasons being hospital-acquired pneumonia (HAP) (n=4), prolonged stay in the high dependency unit (HDU) following postoperative myocardial infarction and cardiac arrest (n=1), failure to tolerate TT occlusion (n=1), and not stated (n=1). There were early postoperative complications in 14 patients but despite this seven decannulations were still performed within two and six days. Additional multiprofessional assessment over weekends is likely to facilitate earlier decannulation. As some TTs are removed after a few days there is a need for better selection to avoid their use in certain patients.

Creating airway management guidelines for casualties with penetrating airway injuries.

Anaesthetists in the Defence Medical Services (DMS) are currently dealing with casualties who have an increased prevalence of injuries due to blast, fragmentation and gunshot wounds. Despite guidelines already existing for unanticipated difficult tracheal intubation these have been designed for a civilian population and might not be relevant for the anticipated difficult airway experienced in the deployed field hospital. In order to establish an overview of current practice, three methods of investigation were undertaken; a literature review, a survey of DMS Anaesthetists and a search of the UKJoint Theatre Trauma Database. Results are discussed in terms of anatomical site, bleeding in the airway, facial distortion, patient positioning and an anaesthetic approach. There are certain key principles that should be considered in all cases and these are considered. Potential pitfalls are discussed and our initial proposed guidelines for use in the deployed field hospital are presented.

Management of anaemia and blood in patients having neck dissections or free flaps for head and neck cancer.

Our main aims were to assess haemoglobin (Hb) concentrations from preoperative assessment to discharge from hospital, and to review which patients had blood transfusions and compliance with national transfusion guidelines. We studied a consecutive series of 131 patients between October 2016 and September 2017 who had either neck dissection or resection and free microvascular tissue transfer. Half the patients had soft tissue free flaps (n = 65), 26% had composite free flaps (n = 34), and 24% neck dissection only (n = 32). Using the WHO definition of anaemia, 4% (1/28) of patients who had neck dissections and 19% (16/85) of those who had free flaps were anaemic preoperatively. The median (IQR) Hb at discharge was 131 (119-144) g/L for patients who had neck dissections, 103 (95-114) g/L for those who had soft free flaps, and 95 (90-104) g/L for those who had composite free flaps. No patients who had neck dissection were given a red blood cell (RBC) transfusion, whereas they were given to 26/99 (26%) of those who had free flaps. Hb concentrations were checked after each unit in 31/39 transfusions (79%). Concentrations for those who had free flaps fell by about 30 g/L from admission to operation, and only four patients were given tranexamic acid peroperatively. Postoperatively Hb remained at similar concentrations until discharge, with 23/98 (24%) given iron orally on discharge. In terms of compliance with blood transfusion guidelines there was a notable absence of the use of tranexamic acid and of iron intravenously. An increase in their use could potentially reduce the number of blood transfusions required and the postoperative incidence of anaemia, and have a favourable effect on outcomes such as complications, fatigue, and overall quality of life.

Validation of linear cerebral atrophy markers in multiple sclerosis.

Linear measures of cerebral ventricular enlargement may act as surrogate measures of cerebral atrophy in multiple sclerosis (MS). Linear atrophy markers were measured from routine MRI scans during a population survey of 171 Tasmanian MS patients and 91 healthy controls. Thirty-five Victorian MS clinic patients were recruited as a validation cohort with 14 of these re-assessed 4 years later. In the population survey, we measured three linear brain atrophy markers: inter-caudate distance (ICD), third ventricle width (TVW) and frontal horn width (FHW). TVW (OR 2.0, p=0.001) and ICD (OR 16.1, p<0.001) differentiated between MS cases and controls. In the validation study, we correlated the intercaudate ratio (ICR=ICD/brain width) and third ventricular ratio (TVR=TVW/brain width) with brain parenchymal volume. Cross-sectionally, ICR (R=-0.453, p<0.01) and TVR (R=-0.653, p<0.01) were correlated with brain parenchymal volume. Longitudinally, brain parenchymal volume loss was inversely correlated with increased ICD (R=-0.77, p<0.01) and TVW (R=-0.71, p<0.01). This study shows that ICD measurements obtained from clinical MRI scans are valid brain atrophy measures for use in monitoring MS progression.

Responsive Contingency Planning: a novel system for anticipated difficulty in airway management in dental abscess.

BACKGROUND: This study is of a novel system for management of anticipated difficult airway (Responsive Contingency Planning). It is based on the notion that almost all problems in airway management have already been experienced, so they can be anticipated and prepared for using 'worst case' planning. METHODS: Anaesthetic colleagues were introduced to the new system. Thirty-two patients with dental abscess were recruited for anaesthetic airway management based around the new scheme. Data collection involved a preoperative assessment of problems specific to dental abscess, fascia-spaces involved, details of the contingency planning process, laryngoscopy grade, and comments regarding the efficacy of the new system. RESULTS: No problems were encountered that had not been anticipated during planning and colleagues' comments about using the system were generally favourable. Examples are highlighted to suggest how the planning may have avoided certain complications (e.g. abscess rupture) and helped in dealing with others when they occurred. If trismus (2 cm) after induction of anaesthesia. In contrast, difficult laryngoscopy (grade 3 or 4) occurred in 6/15 cases of floor of mouth infection. CONCLUSIONS: The system fulfilled expectations for its use at this stage of development. It can be easily updated for refinements, alternative techniques, and tailoring to any difficult airway scenario. Computerization should make it easier to use and flag-up inconsistencies. Floor of mouth infections in the presence of trismus are easily underestimated and require careful assessment.

Skeletal deformities in the elderly and their effect on postural sway.

In a group of 151 elderly men and women (age range, 65-85+), postural sway was studied in relation to various physical attributes and skeletal deformities that might be contributory factors. Weight, loss of height (span-height), scoliosis, grip strength, and the knee angle, measured laterally with the subject erect, all proved to be correlated with postural sway. Kyphosis was related to loss of muscle power and other general indications of frailty. Scoliosis appeared to be related to joint disease in the pelvis and lower limbs.

Sodium valproate in the prophylaxis of simple febrile convulsions.

Thirty children with simple febrile convulsions were treated with sodium valproate following their second convulsion. Twenty-two of the 30 (73%) had no further convulsions during the one-year period of observation compared with 17 of 28 in the control group (61%). This was not a statistically significant difference. Side effects attributed to sodium valproate treatment were noted in 7 patients (23%), although 4 of these showed only mild transient gastrointestinal symptoms at high dosage. The study did not confirm any advantage in the use of sodium valproate as a prophylaxis for febrile convulsions, although compliance was good and significant side effects infrequent.

A radial immunodiffusion method for the assay of factor VIII:C Antigen (VIII:C Ag) in plasma.

A method has been developed for the immunological quantitation of factor VIII:C Ag using a medium titre (50 new Oxford units) factor VIII:C antibody arising in a severe multitransfused haemophiliac. The method, which utilizes clotting inhibition in an agarose gel medium, gave close and significant correlation with the two-stage factor VIII:C procoagulant assay (r=0.83, P less than 0.01) for 54 normal subjects. Similar or higher values were found in 19 mild, moderate and severe haemophiliacs with 2-30% average normal plasma levels of factor VIII:C (r=0.72, P less than 0.01). Four mild von Willebrand patients gave similar results by immunoassay and procoagulant assay methods. A previously identified patient with cross reacting material (CRM+) gave an immunoassay within the normal range (66%) with only 4% VIII:C activity detectable. The method offers a simple, sensitive and apparently reliable procedure for the assay of plasma factor VIII:C Ag which may prove useful in the further investigation of factor VIII:C Ag and antibody heterogeneity. The procedure offers an alternative to immunoradiometric assay and may be of potential use in the assessment of the haemophilia carrier state and possibly the early detection of thrombosis.

Clinical correlates of sway in old age--sensory modalities.

Sway has been measured by Wright's Ataxiameter in 151 frail elderly and five young subjects, and compared with various sensory modalities. There is a close relationship between increased sway and impaired vibration sense in the legs. No correlations emerged with proprioception but this may reflect the imprecision of the test. That neither vision nor vestibular deprivation correlated with sway confirms the place of these senses as secondary in the maintenance of posture. Vestibular impairment was found in only 6% of the elderly subjects, by tilt test--and these were the very old. There was a limited relationship between falls in the past year and both sway and proprioception.