T.M. Cook

Videolaryngoscopy versus direct laryngoscopy for adult patients requiring tracheal intubation: a Cochrane Systematic Review

Difficulties with tracheal intubation commonly arise and impact patient safety. This systematic review evaluates whether videolaryngoscopes reduce intubation failure and complications compared with direct laryngoscopy in adults. We searched CENTRAL, MEDLINE, Embase and clinicaltrials.gov up to February 2015, and conducted forward and backward citation tracking. We included randomized controlled trials that compared adult patients undergoing laryngoscopy with videolaryngoscopy or Macintosh laryngoscopy. We did not primarily intend to compare individual videolaryngoscopes. Sixty-four studies (7044 participants) were included. Moderate quality evidence showed that videolaryngoscopy reduced failed intubations (Odds Ratio (OR) 0.35, 95% Confidence Interval (CI) 0.19-0.65) including in participants with anticipated difficult airways (OR 0.28, 95% CI 0.15-0.55). There was no evidence of reduction in hypoxia or mortality, but few studies reported these outcomes. Videolaryngoscopes reduced laryngeal/airway trauma (OR 0.68, 95% CI 0.48-0.96) and hoarseness (OR 0.57, 95% CI 0.36-0.88). Videolaryngoscopy increased easy laryngeal views (OR 6.77, 95% CI 4.17-10.98) and reduced difficult views (OR 0.18, 95% CI 0.13-0.27) and intubation difficulty, typically using an intubation difficulty score (OR 7.13, 95% CI 3.12-16.31). Failed intubations were reduced with experienced operators (OR 0.32, 95% CI 0.13-0.75) but not with inexperienced users. We identified no difference in number of first attempts and incidence of sore throat. Heterogeneity around time for intubation data prevented meta-analysis. We found evidence of differential performance between different videolaryngoscope designs. Lack of data prevented analysis of impact of obesity or clinical location on failed intubation rates. Videolaryngoscopes may reduce the number of failed intubations, particularly among patients presenting with a difficult airway. They improve the glottic view and may reduce laryngeal/airway trauma. Currently, no evidence indicates that use of a videolaryngoscope reduces the number of intubation attempts or the incidence of hypoxia or respiratory complications, and no evidence indicates that use of a videolaryngoscope affects time required for intubation.

Anaesthesia, surgery, and life-threatening allergic reactions: epidemiology and clinical features of perioperative anaphylaxis in the 6th National Audit Project (NAP6)

Background Anaphylaxis during anaesthesia is a serious complication for patients and anaesthetists. Methods The 6th National Audit Project (NAP6) on perioperative anaphylaxis collected and reviewed 266 reports of Grades 3–5 anaphylaxis over 1 yr from all NHS hospitals in the UK. Results The estimated incidence was ≈1:10 000 anaesthetics. Case exclusion because of reporting delays or incomplete data means true incidence might be ≈70% higher. The distribution of 199 identified culprit agents included antibiotics (94), neuromuscular blocking agents (65), chlorhexidine (18), and Patent Blue dye (9). Teicoplanin comprised 12% of antibiotic exposures, but caused 38% of antibiotic‐induced anaphylaxis. Eighteen patients reacted to an antibiotic test dose. Succinylcholine‐induced anaphylaxis, mainly presenting with bronchospasm, was two‐fold more likely than other neuromuscular blocking agents. Atracurium‐induced anaphylaxis mainly presented with hypotension. Non‐depolarising neuromuscular blocking agents had similar incidences to each other. There were no reports of local anaesthetic or latex‐induced anaphylaxis. The commonest presenting features were hypotension (46%), bronchospasm (18%), tachycardia (9.8%), oxygen desaturation (4.7%), bradycardia (3%), and reduced/absent capnography trace (2.3%). All patients were hypotensive during the episode. Onset was rapid for neuromuscular blocking agents and antibiotics, but delayed with chlorhexidine and Patent Blue dye. There were 10 deaths and 40 cardiac arrests. Pulseless electrical activity was the usual type of cardiac arrest, often with bradycardia. Poor outcomes were associated with increased ASA, obesity, beta blocker, and angiotensin‐converting enzyme inhibitor medication. Seventy per cent of cases were reported to the hospital incident reporting system, and only 24% to Medicines and Healthcare products Regulatory Agency via the Yellow Card Scheme. Conclusions The overall incidence of perioperative anaphylaxis was estimated to be 1 in 10 000 anaesthetics.

Strategies for the prevention of airway complications – a narrative review

Despite being infrequent, complications of airway management remain an important contributor to morbidity and mortality during anaesthesia and care of the critically ill. Developments in the last three decades have made anaesthesia safer, and this has been mirrored in the equipment and techniques available for airway management. Modern technology including novel oxygenation modalities, widespread availability of capnography, second‐generation supraglottic airway devices and videolaryngoscopy provide the tools to make airway management safer still. However, technology will only take safety so far, and non‐technical aspects of airway management are critically important for communication and decision making during airway crises, acknowledging a ‘cannot intubate, cannot oxygenate’ situation and transitioning to emergency front of neck airway. Randomised controlled trials provide little useful information about safety in this setting, and data from registries and databases are likely to be of more value. This narrative review focuses on recent evidence in this area.

Cross-sectional study of perioperative drug and allergen exposure in UK practice in 2016: the 6th National Audit Project (NAP6) Allergen Survey

Background Details of the current UK drug and allergen exposure were needed for interpretation of reports of perioperative anaphylaxis to the 6th National Audit Project (NAP6). Methods We performed a cross‐sectional survey of 356 NHS hospitals determining anaesthetic drug usage in October 2016. All cases cared for by an anaesthetist were included. Results Responses were received from 342 (96%) hospitals. Within‐hospital return rates were 96%. We collected 15 942 forms, equating to an annual caseload of 3.1 million, including 2.4 million general anaesthetics. Propofol was used in 74% of all cases and 90% of general anaesthetics. Maintenance included a volatile agent in 95% and propofol in 8.7%. Neuromuscular blocking agents were used in 47% of general anaesthetics. Analgesics were used in 88% of cases: opioids, 82%; paracetamol, 56%; and non‐steroidal anti‐inflammatory drugs, 28%. Antibiotics were administered in 57% of cases, including 2.5 million annual perioperative administrations; gentamicin, co‐amoxiclav, and cefuroxime were most commonly used. Local anaesthetics were used in 74% cases and 70% of general anaesthetics. Anti‐emetics were used in 73% of cases: during general anaesthesia, ondansetron in 78% and dexamethasone in 60%. Blood products were used in ≈3% of cases, gelatin <2%, starch very rarely, and tranexamic acid in ≈6%. Chlorhexidine and povidone‐iodine exposures were 74% and 40% of cases, and 21% reported a latex‐free environment. Exposures to bone cement, blue dyes, and radiographic contrast dye were each reported in 2–3% of cases. Conclusions This survey provides insights into allergen exposures in perioperative care, which is important as denominator data for the NAP6 registry.

Anaesthesia, surgery, and life-threatening allergic reactions: protocol and methods of the 6th National Audit Project (NAP6) of the Royal College of Anaesthetists

Background Anaphylaxis during anaesthesia is a serious complication for patients and anaesthetists. Methods The Sixth National Audit Project (NAP6) of the Royal College of Anaesthetists examined the incidence, predisposing factors, management, and impact of life‐threatening perioperative anaphylaxis in the UK. NAP6 included: a national survey of anaesthetists’ experiences and perceptions; a national survey of allergy clinics; a registry collecting detailed reports of all Grade 3–5 perioperative anaphylaxis cases for 1 yr; and a national survey of anaesthetic workload and perioperative allergen exposure. NHS and independent sector (IS) hospitals were approached to participate. Cases were reviewed by a multi‐disciplinary expert panel (anaesthetists, intensivists, allergists, immunologists, patient representatives, and stakeholders) using a structured process designed to minimise bias. Clinical management and investigation were compared with published guidelines. This paper describes detailed study methods and reports on project engagement by NHS and IS hospitals. The methodology includes a new classification of perioperative anaphylaxis and a new structured method for classifying suspected anaphylactic events including the degree of certainty with which a causal trigger agent can be attributed. Results NHS engagement was complete (100% of hospitals). Independent sector engagement was limited (13% of approached hospitals). We received >500 reports of Grade 3–5 perioperative anaphylaxis, with 266 suitable for analysis. We identified 199 definite or probable culprit agents in 192 cases. Conclusions The methods of NAP6 were robust in identifying causative agents of anaphylaxis, and support the accompanying analytical papers.

An observational national study of anaesthetic workload and seniority across the working week and weekend in the UK in 2016: the 6th National Audit Project (NAP6) Activity Survey

Background UK national anaesthetic activity was studied in 2013 but weekend working was not examined. Understanding changes since 2013 in workload and manpower distribution, including weekends, would be of value in workforce planning. Methods We performed an observational survey of NHS hospitals’ anaesthetic practice in October 2016 as part of the 6th National Audit Project of the Royal College of Anaesthetists (NAP6). All cases cared for by an anaesthetist during the study period were included. Patient characteristics and details of anaesthetic conduct were collected by local anaesthetists. Results Responses were received from 342/356 (96%) hospitals. In total, 15 942 cases were reported, equating to an annual anaesthetic workload of ≈3.13 million cases. Approximately 95% (9888/10 452) of elective and 72% (3184/4392) of emergency work was performed on weekdays and 89% (14 145/15 942) of activity was led by senior (consultant or career grade) anaesthetists and 1.1% (180/15942) by those with <2 yr anaesthetic experience. During weekends case urgency increased, the proportion of healthy patients reduced and case mix changed. Cases led by senior anaesthetists fell to 80% (947/1177) on Saturday and 66% (342/791) on Sunday. Senior involvement in obstetric anaesthetic activity was 69% (628/911) during the week and 45% (182/402) at weekends, compared with 93% (791/847) in emergency orthopaedic procedures during the week and 89% (285/321) at weekends. Since 2013, the proportion of obese patients, elective weekend working, and depth of anaesthesia monitoring has increased [12% (1464/12 213) vs 2.8%], but neuromuscular monitoring has not [37% (2032/5532) vs 38% of paralysed cases]. Conclusions Senior clinicians deliver most UK anaesthesia care, including at weekends. Our findings are important for any planned workforce reorganisation to rationalise 7‐day working.

Anaesthesia, surgery, and life-threatening allergic reactions: management and outcomes in the 6th National Audit Project (NAP6)

Background Anaphylaxis during anaesthesia is a serious complication for patients and anaesthetists. There is little published information on management and outcomes of perioperative anaphylaxis in the UK. Methods The 6th National Audit Project of the Royal College of Anaesthetists (NAP6) collected and reviewed 266 reports of Grade 3–5 anaphylaxis from all UK NHS hospitals over 1 yr. Quality of management was assessed against published guidelines. Results Appropriately senior anaesthetists resuscitated all patients. Immediate management was ‘good’ in 46% and ‘poor’ in 15%. Recognition and treatment of anaphylaxis were prompt in 97% and 83% of cases, respectively. Epinephrine was administered i.v. in 76%, i.m. in 14%, both in 6%, and not at all in 11% of cases. A catecholamine infusion was administered in half of cases. Cardiac arrests (40 cases; 15%) were promptly treated but cardiac compressions were omitted in half of patients with unrecordable BP. The surgical procedure was abandoned in most cases, including 10% where surgery was urgent. Of 54% admitted to critical care, 70% were level 3, with most requiring catecholamine infusions. Ten (3.8%) patents (mostly elderly with cardiovascular disease) died from anaphylaxis. Corticosteroids and antihistamines were generally administered early. We found no clear evidence of harm or benefit from chlorphenamine. Two patients received vasopressin and one glucagon. Fluid administration was inadequate in 19% of cases. Treatment included sugammadex in 19 cases, including one when rocuronium had not been administered. Adverse sequelae (psychological, cognitive, or physical) were reported in one‐third of cases. Conclusions Management of perioperative anaphylaxis could be improved, especially with respect to administration of epinephrine, cardiac compressions, and i.v. fluid. Sequelae were common.

Specialist perioperative allergy clinic services in the UK 2018: Results from the Royal College of Anaesthetists Sixth National Audit Project (NAP6) investigation of perioperative anaphylaxis

The Royal College of Anaesthetists 6th National Audit Project examined Grade 3‐5 perioperative anaphylaxis for 1 year in the UK.

Universal videolaryngoscopy: a structured approach to conversion to videolaryngoscopy for all intubations in an anaesthetic and intensive care department

Background: Videolaryngoscopy (VL) is increasingly used, but not yet routine practice, for tracheal intubation. Few departments formally trial equipment before adopting it into practice. We describe the decision‐making and implementation processes that our department used when introducing universal VL, with the C‐MAC© (Karl Storz, Germany), throughout our anaesthesia and intensive care departments. Methods: We used a structured process to assess the feasibility of a change to universal VL. After departmental training, we undertook a 2 month trial period of mandating VL for all adult in‐theatre intubations. Thereafter, VL remained widely available, but not mandated. We regularly surveyed anaesthetists and anaesthetic assistants to evaluate departmental opinion regarding the introduction of universal VL. Results: Before the trial period, one‐third of anaesthetists judged that universal VL would be of overall benefit to patient safety, team dynamics, and quality of care. Reservations from both junior and senior anaesthetists focused on training concerns. Support for a changeover to VL, amongst both anaesthetists and anaesthetic assistants, increased throughout the trial period. Six months after the 2 month trial, support had grown further and was almost unanimous. Anaesthetists reported significant benefits in clinical performance, teaching, and human factors, especially teamwork and situation awareness. Conclusions: Performing a formal and prolonged trial of mandatory VL in theatre led to changes in perceptions and departmental consensus. As a result of the trial, the department agreed to the use of C‐MAC© videolaryngoscopy as the default intubation technique throughout theatres and intensive care, with removal of standard Macintosh laryngoscopes from routine use.

Nitrous oxide‐based vs. nitrous oxide‐free general anaesthesia and accidental awareness in surgical patients: an abridged Cochrane systematic review

Accidental awareness during general anaesthesia can arise from a failure to deliver sufficient anaesthetic agent, or from a patients resistance to an expected sufficient dose of such an agent. Awareness is ‘explicit’ if the patient is subsequently able to recall the event. We conducted a systematic review into the effect of nitrous oxide used as part of a general anaesthetic on the risk of accidental awareness in people over the age of five years undergoing general anaesthesia for surgery. We included 15 randomised controlled trials, 14 of which, representing a total of 3439 participants, were included in our primary analysis of the frequency of accidental awareness events. The awareness incidence rate was rare within these studies, and all were considered underpowered with respect to this outcome. The risk of bias across all studies was judged to be high, and 76% of studies failed adequately to conceal participant allocation. We considered the available evidence to be of very poor quality. There were a total of three accidental awareness events reported in two studies, one of which reported that the awareness was the result of a kink in a propofol intravenous line. There were insufficient data to conduct a meta‐ or sub‐group analysis and there was insufficient evidence to draw outcome‐related conclusions. We can, however, recommend that future studies focus on potentially high‐risk groups such as obstetric or cardiac surgery patients, or those receiving neuromuscular blocking drugs or total intravenous anaesthesia.