New guidelines for research in airway device evaluation: time for an updated approach (ADEPT-2) to the Difficult Airway Society's 'ADEPT' strategy?

In this article we present the learning from a clinical study of airway device evaluation, conducted under the framework of the Difficult Airway Society (DAS, UK) 'ADEPT' (airway device evaluation project team) strategy. We recommend a change in emphasis from small scale randomised controlled trials conducted as research, to larger-scale observational, post-marketing evaluation audits as a way of obtaining more meaningful information.

The lure of the Lüer connector: Non-Lüer connectors in regional anaesthesia.

Health service professionals do not have perfect vigilance. There will always be the possibility that a serious untoward incident can occur due to crossover injections of medication being administered via the wrong route. The universality of the Lüer connector made it very easy to connect several medical devices for different therapeutic uses. Although this was considered a bonus, it also showed the downside as a string of incidents, leading to permanent harm and even death, occurred, warranting actions to prevent the chance of misconnections and wrong-route injections. The International Organisation for Standardisation introduced specific ISO 80 369 connectors for use in different medical systems, with the ISO 80369-6 series of standards specifically designed to improve safety in regional anaesthesia. Human error can never be completely eliminated, but the risk of a patient inadvertently suffering from an inadvertent wrong-route injection can be reduced through the use of new 'fit and no-fit' technology. This article focuses on the universality of the Lüer connector and the introduction of the newly engineered non-Lüer connectors, for specific use in medical systems.

Baseline parameters for rotational thromboelastometry in healthy labouring women: a prospective observational study.

OBJECTIVE: The aim of this study was to establish rotational thromboelastometry (ROTEM® ) baseline parameters in labouring women at term gestation. The secondary aim was to compare these reference ranges with those from previous studies on labouring women and from the manufacturer. DESIGN: A prospective, observational study. SETTING: Tertiary referral hospital. PARTICIPANTS: Healthy women in labour. METHODS: Ethics approval was granted for an opt-out recruitment approach. ROTEM® testing was performed in labouring women at term gestation. Women with any condition affecting coagulation were excluded. ROTEM® Delta reference ranges were derived by calculating the 2.5% and 97.5% centiles for INTEM/EXTEM/FIBTEM parameters including amplitude at 5 minutes (A5), coagulation time (CT) and maximum clot firmness (MCF). MAIN OUTCOME MEASURES: ROTEM® parameters were measured in labouring women before delivery. The following tests were performed: FIBTEM, EXTEM and INTEM. RESULTS: One hundred and twenty-one women met the inclusion criteria, with a mean (± SD) age of 29.6 ± 5.4 years and median (interquartile range) gestation of 39.4 weeks (37.4-40.4 weeks). Seventy-five (62.0%) women were nulliparous and 71 (58.7%) delivered vaginally. The median and interquartile ranges for selected ROTEM® parameters were: FIBTEM A5, 21 mm (IQR 18-23 mm); EXTEM A5, 55 mm (52-58 mm); and EXTEM CT, 52 seconds (48-56 seconds). CONCLUSIONS: The FIBTEM/EXTEM/INTEM amplitudes were higher than the manufacturer's reference ranges for non-obstetric patients. The FIBTEM MCF upper and lower limits were higher and the EXTEM/INTEM CT was shorter and narrower in range. This study provides reference ranges for ROTEM® values in healthy labouring women at term gestation with uncomplicated pregnancies. TWEETABLE ABSTRACT: This is the first study to report on ROTEM® reference ranges with over 120 healthy labouring women of normal weight at term gestation.

Epidural extension failure in obese women is comparable to that of non-obese women.

BACKGROUND: Management of labor epidurals in obese women is difficult and extension to surgical anesthesia is not always successful. Our previous retrospective pilot study found epidural extension was more likely to fail in obese women. This study used a prospective cohort to compare the failure rate of epidural extension in obese and non-obese women and to identify risk factors for extension failure. METHODS: One hundred obese participants (Group O, body mass index ≥ 40 kg/m2 ) were prospectively identified and allocated two sequential controls (Group C, body mass index ≤ 30 kg/m2 ). All subjects utilized epidural labor analgesia and subsequently required anesthesia for cesarean section. The primary outcome measure was failure of the labor epidural to be used as the primary anesthetic technique. Risk factors for extension failure were identified using Chi-squared and logistic regression. RESULTS: The odds ratio (OR) of extension failure was 1.69 in Group O (20% vs. 13%; 95% CI: 0.88-3.21, P = 0.11). Risk factors for failure in obese women included ineffective labor analgesia requiring anesthesiologist intervention, (OR 3.94, 95% CI: 1.16-13.45, P = 0.028) and BMI > 50 kg/m2 (OR 3.42, 95% CI: 1.07-10.96, P = 0.038). CONCLUSION: The failure rate of epidural extension did not differ significantly between the groups. Further research is needed to determine the influence of body mass index > 50 kg/m2 on epidural extension for cesarean section.

Tracheal extubation of the adult intensive care patient with a predicted difficult airway - a narrative review.

Management of the difficult airway is an important, but as yet poorly-studied, component of intensive care management. Although there has been a strong emphasis on prediction and intubation of the difficult airway, safe extubation of the patient with a potentially difficult airway has not received the same attention. Extubation is a particularly vulnerable time for the critically ill patient and, because of the risks involved and the consequences of failure, it warrants specific consideration. The Royal College of Anaesthetists 4th National Audit Project highlighted differences in the incidence and consequences of major complications during airway management between the operating room and the critical care environment. The findings in the section on Intensive Care and Emergency Medicine reinforce the importance of good airway management in the critical care environment and, in particular, the need for appropriate guidelines to improve patient safety. This narrative review focuses on strategies for safe extubation of the trachea for patients with potentially difficult upper airway problems in the intensive care unit.

Videolaryngoscopy vs. direct laryngoscopy use by experienced anaesthetists in patients with known difficult airways: a systematic review and meta-analysis.

Experienced anaesthetists can be confronted with difficult or failed tracheal intubations. We performed a systematic review and meta-analysis to ascertain if the literature indicated if videolaryngoscopy conferred an advantage when used by experienced anaesthetists managing patients with a known difficult airway. We searched PubMed, MEDLINE, Embase and the Cochrane central register of controlled trials up to 1 January 2017. Outcome parameters extracted from studies were: first-attempt success of tracheal intubation; time to successful intubation; number of intubation attempts; Cormack and Lehane grade; use of airway adjuncts (e.g. stylet, gum elastic bougie); and complications (e.g. mucosal and dental trauma). Nine studies, including 1329 patients, fulfilled the inclusion criteria. First-attempt success was greater for all videolaryngoscopes (OR 0.34 (95%CI 0.18-0.66); p = 0.001). Use of videolaryngoscopy was associated with a significantly better view of the glottis (Cormack and Lehane grades 1 and 2 vs. 3-4, OR 0.04 (95%CI 0.01-0.15); p < 0.00001). Mucosal trauma occurred less with the use of videolaryngoscopy (OR 0.16 (95%CI 0.04-0.75); p = 0.02). Videolaryngoscopy has added value for the experienced anaesthetist, improving first-time success, the view of the glottis and reducing mucosal trauma.

Comparison of seven videolaryngoscopes with the Macintosh laryngoscope in manikins by experienced and novice personnel.

Videolaryngoscopy is often reserved for 'anticipated' difficult airways, but thereby can result in a higher overall rate of complications. We observed 65 anaesthetists, 67 residents in anaesthesia, 56 paramedics and 65 medical students, intubating the trachea of a standardised manikin model with a normal airway using seven devices: Macintosh classic laryngoscope, Airtraq(®) , Storz C-MAC(®) , Coopdech VLP-100(®) , Storz C-MAC D-Blade(®) , GlideScope Cobalt(®) , McGrath Series5(®) and Pentax AWS(®) ) in random order. Time to and proportion of successful intubation, complications and user satisfaction were compared. All groups were fastest using devices with a Macintosh-type blade. All groups needed significantly more attempts using the Airtraq and Pentax AWS (all p < 0.05). Devices with a Macintosh-type blade (classic laryngoscope and C-MAC) scored highest in user satisfaction. Our results underline the importance of variability in device performance across individuals and staff groups, which have important implications for which devices hospital providers should rationally purchase.

Perioperative statin therapy in patients at high risk for cardiovascular morbidity undergoing surgery: a review.

Statins feature documented benefits for primary and secondary prevention of cardiovascular disease and are thought to improve perioperative outcomes in patients undergoing surgery. To assess the clinical outcomes of perioperative statin treatment in statin-naive patients undergoing surgery, a systematic review was performed. Studies were included if they met the following criteria: randomized controlled trials, patients aged ≥18 yr undergoing surgery, patients not already on long-term statin treatment, reported outcomes including at least one of the following: mortality, myocardial infarction, atrial fibrillation, stroke, and length of hospital stay. The following randomized clinical trials were excluded: retrospective studies, trials without surgical procedure, trials without an outcome of interest, studies with patients on statin therapy before operation, or papers not written in English. The literature search revealed 16 randomized controlled studies involving 2275 patients. Pooled results showed a significant reduction in (i) mortality [risk ratio (RR) 0.53, 95% confidence interval (CI) 0.30-0.94, P=0.03], (ii) myocardial infarction (RR 0.54, 95% CI 0.38-0.76, P<0.001), (iii) perioperative atrial fibrillation (RR 0.53, 95% CI 0.43-0.66, P<0.001), and (iv) length of hospital stay (days, mean difference -0.58, 95% CI -0.79 to -0.37, P<0.001) in patients treated with a statin. Subgroup analysis in patients undergoing non-cardiac surgery showed a decrease in the perioperative incidence of mortality and myocardial infarction. Consequently, anaesthetists should consider prescribing a standard-dose statin before operation to statin-naive patients undergoing cardiac surgery. However, there are insufficient data to support final recommendations on perioperative statin therapy for patients undergoing non-cardiac surgery.

Reducing the immediate availability of red blood cells in cardiac surgery, a single-centre experience.

BACKGROUND: In our institution, we have redefined our criteria for direct availability of red blood cell (RBC) units in the operation room. In this study, we sought to evaluate the safety of applying this new logistical policy of blood transfusion in the first preliminary group of patients. METHODS: In March 2010, we started a new policy concerning the elective availability of RBC units in the operation room. This policy was called: No Elective Red Cells (NERC) program. The program was applied for patients undergoing primary isolated coronary artery bypass grafting (CABG) or single valve surgery. No elective RBC units were preoperatively ordered for these patients. In case of urgent need, blood was delivered to the operating room within 20 min. The present study includes the first 500 patients who were managed according to this policy. Logistic regression analyses were performed to investigate the impact of biomedical variables on fulfilling this NERC program. RESULTS: The majority of patients (n = 409, 81 %) did not receive any RBCs during the hospital stay. In patients who did receive RBCs (n = 91, 19 %), 11 patients (2.2 %) received RBCs after 24 h postoperatively. Female gender, left ventricular ejection fraction (LVEF) and EuroSCORE were significant predictors for the need of blood transfusion (OR = 3.12; 2.79; 1.17 respectively). CONCLUSION: In a selected group of patients, it is safe to perform cardiac surgery without the immediate availability of RBCs in the operating room. Transfusion was avoided in 81 % of these patients. Female gender, LVEF and EuroSCORE were associated with blood transfusion.

The LMA-Supreme™ as an intubation conduit in patients with known difficult airways: a prospective evaluation study.

BACKGROUND: Many extraglottic airway devices allow the direct passage of an adult-sized tracheal tube, but this is not possible with the LMA-Supreme(TM) . We evaluated the feasibility of using the LMA-Supreme(TM) as a conduit for intubation in patients with known difficult airways. METHODS: Sixty-eight adult patients, with preoperative predictors of difficult intubation, were scheduled for elective surgery under general anaesthesia. After assessing the direct laryngoscopy view, 23 patients with Cormack-Lehane III/IV were included in the study. An LMA-Supreme(TM) was inserted, followed by the passage of a flexible bronchoscope loaded with an Aintree Intubation Catheter into the trachea. The bronchoscope and LMA-Supreme(TM) were removed, and a tracheal tube was railroaded over the Aintree Intubation Catheter into the trachea. RESULTS: Tracheal intubation was successful in all patients using the above technique. SpO(2) was >95% during the intubation procedure. CONCLUSIONS: We conclude that the LMA-Supreme(TM) is a successful conduit for bronchoscopic/Aintree Intubation Catheter-guided intubation in patients with known difficult airway.

Forces applied to the maxillary incisors by video laryngoscopes and the Macintosh laryngoscope.

BACKGROUND: Modern video laryngoscopes (VLSs) provide a superior view of the glottis, facilitating easier intubations. This study evaluates the forces applied to the maxillary incisors when using various VLSs and a Macintosh blade. METHODS: Fifty consecutive surgery patients were randomly assigned to receive laryngoscopy from a pair of four blades investigated in the study - the VLS GlideScope(®) (Verathon Inc., Bothell, WA, USA), V-Mac™ Storz(®) (Karl Storz, Tuttlingen, Germany), and McGrath™ (Aircraft Medical, Edinburgh, United Kingdom); and the classic Macintosh blade also from Storz(®) (Karl Storz). An endotracheal tube (ETT) was brought into position anterior to the vocal cords, with actual intubation carried out only with the second of the laryngoscopes. Sensors measured the forces directly applied to the patient's maxillary incisors while inserting the ETT. Other common metrics of intubation difficulty (e.g. Mallampati grade, Cormack-Lehane grade, and time) were also recorded. RESULTS: Only one patient was not intubated within the standard study parameters and was converted to the hospital protocols for difficult intubations. The forces applied to the maxillary incisors were significantly greater with the Macintosh blade compared with all VLSs. There were no differences between the VLSs with regard to the forces. Patient characteristics, including Mallampati grade, were not predictive of the forces applied. CONCLUSIONS: All VLSs considered were safer for the patient than was the Macintosh blade in terms of the forces applied to the maxillary teeth, time, number of insertion attempts, and view achieved of the glottic arch. There is a small, but significant, difference in the time and number of insertion attempts required during laryngoscopy with the different VLSs. There was no difference in the forces applied. The geometry of the respective blades may be an important component in the ease of laryngoscopy.