Cortisol awakening response in the airborne rescue service.

BACKGROUND: Work-related stress may lead to mental and physical illnesses. Emergency physicians may be particularly vulnerable to developing such diseases due to their extreme emotional working environment. AIMS: The purpose of the study was to analyse the hormonal stress burden of emergency physicians in the airborne rescue service to create an empirical basis for developing appropriate measures against chronic stress in the rescue service. METHODS: Three salivary cortisol samples were collected after awakening in 15 min intervals-each on a flight rescue day, a clinic day and a free day-to calculate the extent of the hormonal stress load of the emergency physicians. A nested linear mixed-model analysis was used in 40 cases to investigate hormonal stress. Furthermore, professional years and gender were included in the calculations. RESULTS: The mixed model showed neither a main effect for measurement time nor for day but a significant interaction effect (P = 0.002). The cortisol level rises strongly on the flight rescue and the clinic day, while on the free day it shows a moderate increase. Professional years and gender also proved to be statistically significant for the cortisol level of emergency physicians (P < 0.001). CONCLUSIONS: The results show a significantly higher cortisol increase on working days compared with a free day, which indicates a stronger stress burden on working days of emergency physicians in the airborne rescue service. Future studies should examine the stress level of emergency physicians in more detail to prove whether the working conditions of emergency physicians need to be modified.

Five-year audit of adherence to an anaesthesia pre-induction checklist.

Although patient safety related to airway management has improved substantially over the last few decades, life-threatening events still occur. Technical skills, clinical expertise and human factors contribute to successful airway management. Checklists aim to improve safety by providing a structured approach to equipment, personnel and decision-making. This audit investigates adherence to our institution's airway checklist from 1 June 2016 to 31 May 2021. Inclusion criteria were procedures requiring airway management and we excluded all procedures performed solely under regional anaesthesia, sedation without airway management or paediatric and cardiovascular surgery. The primary outcome was the proportion of wholly performed pre-induction checklists. Secondary outcomes were the pattern of adherence over the 5 years well as details of airway management, including: airway management difficulties; time and location of induction; anaesthesia teams in operating theatres (including teams for different surgical specialities); non-operating theatre and emergency procedures; type of anaesthesia (general or combined); and urgency of the procedure. In total, 95,946 procedures were included. In 57.3%, anaesthesia pre-induction checklists were completed. Over the 5 years after implementation, adherence improved from 48.3% to 66.7% (p < 0.001). Anticipated and unanticipated airway management difficulties (e.g. facemask ventilation, supraglottic airway device or intubation) defined by the handling anaesthetist were encountered in 4.2% of all procedures. Completion of the checklist differed depending on the time of day (61.3% during the day vs. 35.0% during the night, p < 0.001). Completion also differed depending on location (66.8% in operating theatres vs. 41.0% for non-operating theatre anaesthesia, p < 0.001) and urgency of procedure (65.4% in non-emergencies vs. 35.4% in emergencies, p < 0.001). A mixed-effect model indicated that urgency of procedure is a strong predictor for adherence, with emergency cases having lower adherence (OR 0.58, 95%CI 0.49-0.68, p < 0.001). In conclusion, over 5 years, a significant increase in adherence to an anaesthesia pre-induction checklist was found, and areas for further improvement (e.g. emergencies, non-operating room procedures, night-time procedures) were identified.

Pre-oxygenation using high-flow nasal oxygen vs. tight facemask during rapid sequence induction.

Pre-oxygenation using high-flow nasal oxygen can decrease the risk of desaturation during rapid sequence induction in patients undergoing emergency surgery. Previous studies were single-centre and often in limited settings. This randomised, international, multicentre trial compared high-flow nasal oxygen with standard facemask pre-oxygenation for rapid sequence induction in emergency surgery at all hours of the day and night. A total of 350 adult patients from six centres in Sweden and one in Switzerland undergoing emergency surgery where rapid sequence induction was required were included and randomly allocated to pre-oxygenation with 100% oxygen using high-flow nasal oxygen or a standard tight-fitting facemask. The primary outcome was the number of patients developing oxygen saturations <93% from the start of pre-oxygenation until 1 min after tracheal intubation. Data from 349 of 350 patients who entered the study were analysed (174 in the high-flow nasal oxygen group and 175 in the facemask group). No difference was detected in the number of patients desaturating <93%, five (2.9%) vs. six (3.4%) patients in the high-flow nasal oxygen and facemask group, respectively (p = 0.77). The risk of desaturation was not increased during on-call hours. No difference was seen in end-tidal carbon dioxide levels in the first breath after tracheal intubation or in the number of patients with signs of regurgitation between groups. These results confirm that high-flow nasal oxygen maintains adequate oxygen levels during pre-oxygenation for rapid sequence induction.

Evaluating the ventilatory effect of transnasal humidified rapid insufflation ventilatory exchange in apnoeic small children with two different oxygen flow rates: a randomised controlled trial.

Transnasal humidified rapid insufflation ventilatory exchange prolongs safe apnoeic oxygenation time in children. In adults, transnasal humidified rapid insufflation ventilatory exchange is reported to have a ventilatory effect with PaCO2 levels increasing less rapidly than without it. This ventilatory effect has yet to be reproduced in children. In this non-inferiority study, we tested the hypothesis that children weighing 10-15 kg exhibit no difference in carbon dioxide clearance when comparing two different high-flow nasal therapy flow rates during a 10-min apnoea period. Following standardised induction of anaesthesia including neuromuscular blockade, patients were randomly allocated to high-flow nasal therapy of 100% oxygen at 2 or 4 l.kg-1 .min-1 . Airway patency was ensured by continuous jaw thrust. The study intervention was terminated for safety reasons when SpO2 values dropped < 95%, or transcutaneous carbon dioxide levels rose > 9.3 kPa, or near-infrared spectroscopy values dropped > 20% from their baseline values, or after an apnoeic period of 10 min. Fifteen patients were included in each group. In the 2 l.kg-1 .min-1 group, mean (SD) transcutaneous carbon dioxide increase was 0.46 (0.11) kPa.min-1 , while in the 4 l.kg-1 .min-1 group it was 0.46 (0.12) kPa.min-1 . The upper limit of a one-sided 95%CI for the difference between groups was 0.07 kPa.min-1 , lower than the predefined non-inferiority margin of 0.147 kPa.min-1 (p = 0.001). The lower flow rate of 2 l.kg-1 .min-1 was non-inferior to 4 l.kg-1 .min-1 relative to the transcutaneous carbon dioxide increase. In conclusion, an additional ventilatory effect of either 2 or 4 l.kg-1 .min-1 high-flow nasal therapy in apnoeic children weighing 10-15 kg appears to be absent.

Measurement of airway pressure during high-flow nasal therapy in apnoeic oxygenation: a randomised controlled crossover trial.

It is recognised that high-flow nasal therapy can prevent desaturation during airway management. Studies in spontaneously breathing patients show an almost linear relationship between flow rate and positive airway pressure in the nasopharynx. Positive airway pressure has been suggested as one of the possible mechanisms explaining how high-flow nasal therapy works. However, data on pressures generated by high-flow nasal therapy in apnoeic adults under general anaesthesia are absent. This randomised controlled crossover trial investigated airway pressures generated by different flow rates during high-flow nasal therapy in anaesthetised and paralysed apnoeic patients, comparing pressures with closed and open mouths. Following induction of anaesthesia and neuromuscular blockade, a continuous jaw thrust was used to enable airway patency. Airway pressure was measured in the right main bronchus, the middle of the trachea and the pharynx, using a fibreoptically-placed catheter connected to a pressure transducer. Each measurement was randomised with respect to closed or open mouth and different flow rates. Twenty patients undergoing elective surgery were included (mean (SD) age 38 (18) years, BMI 25.0 (3.3) kg.m-2 , nine women, ASA physical status 1 (35%), 2 (55%), 3 (10%). While closed mouths and increasing flow rates demonstrated non-linear increases in pressure, the pressure increase was negligible with an open mouth. Airway pressures remained below 10 cmH2 O even with closed mouths and flow rates up to 80 l.min-1 ; they were not influenced by catheter position. This study shows an increase in airway pressures with closed mouths that depends on flow rate. The generated pressure is negligible with an open mouth. These data question positive airway pressure as an important mechanism for maintenance of oxygenation during apnoea.

Transnasal humidified rapid insufflation ventilatory exchange for oxygenation of children during apnoea: a prospective randomised controlled trial.

BACKGROUND: Transnasal humidified rapid insufflation ventilatory exchange (THRIVE) comprises the administration of heated, humidified, and blended air/oxygen mixtures via nasal cannula at rates of ≥2 litres kg-1 min-1. The aim of this randomized controlled study was to evaluate the length of the safe apnoea time using THRIVE with two different oxygen concentrations (100% vs 30% oxygen) compared with standard low-flow 100% oxygen administration. METHODS: Sixty patients, aged 1-6 yr, weighing 10-20 kg, undergoing general anaesthesia for elective surgery, were randomly allocated to receive one of the following oxygen administration methods during apnoea: 1) low-flow 100% oxygen at 0.2 litres kg-1 min-1; 2) THRIVE 100% oxygen at 2 litres kg-1 min-1; and 3) THRIVE 30% oxygen at 2 litres kg-1 min-1. Primary outcome was time to desaturation to 95%. Termination criteria included SpO2 decreased to 95%, transcutaneous CO2 increased to 65 mmHg, or apnoea time of 10 min. RESULTS: The median (interquartile range) [range] apnoea time was 6.9 (5.7-7.8) [2.8-10.0] min for low-flow 100% oxygen, 7.6 (6.2-9.1) [5.2-10.0] min for THRIVE 100% oxygen, and 3.0 (2.4-3.7) [0.2-5.3] min for THRIVE 30% oxygen. No significant difference was detected between apnoea times with low-flow and THRIVE 100% oxygen administration (P=0.15). THRIVE with 30% oxygen demonstrated significantly shorter apnoea times (P<0.001) than both 100% oxygen modalities. The overall rate of transcutaneous CO2 increase was 0.57 (0.49-0.63) [0.29-8.92] kPa min-1 without differences between the 3 groups (P=0.25). CONCLUSIONS: High-flow 100% oxygen (2 litres kg-1 min-1) administered via nasal cannulas did not extend the safe apnoea time for children weighing 10-20 kg compared with low-flow nasal cannula oxygen (0.2 litres kg-1 min-1). No ventilatory effect was observed with THRIVE at 2.0 litres kg-1 min-1. CLINICAL TRIAL REGISTRATION: NCT02979067.

A randomised, controlled trial evaluating a low cost, 3D-printed bronchoscopy simulator.

Low-fidelity, simulation-based psychomotor skills training is a valuable first step in the educational approach to mastering complex procedural skills. We developed a cost-effective bronchial tree simulator based on a human thorax computed tomography scan using rapid-prototyping (3D-print) technology. This randomised, single-blind study evaluated how realistic our 3D-printed simulator would mimic human anatomy compared with commercially available bronchial tree simulators (Laerdal® Airway Management Trainer with Bronchial Tree and AirSim Advance Bronchi, Stavanger, Norway). Thirty experienced anaesthetists and respiratory physicians used a fibreoptic bronchoscope to rate each simulator on a visual analogue scale (VAS) (0 mm = completely unrealistic anatomy, 100 mm = indistinguishable from real patient) for: localisation of the right upper lobe bronchial lumen; placement of a bronchial blocker in the left main bronchus; aspiration of fluid from the right lower lobe; and overall realism. The 3D-printed simulator was rated most realistic for the localisation of the right upper lobe bronchial lumen (p = 0.002), but no differences were found in placement of a bronchial blocker or for aspiration of fluid (p = 0.792 and p = 0.057) compared with using the commercially available simulators. Overall, the 3D-printed simulator was rated most realistic (p = 0.021). Given the substantially lower costs for the 3D-printed simulator (£85 (€100/US$110) compared with > ~ £2000 (€2350/US$2590) for the commercially available simulators), our 3D-printed simulator provides an inexpensive alternative for learning bronchoscopy skills, and offers the possibility of practising procedures on patient-specific models before attempting them in clinical practice.

Evaluation of three unchannelled videolaryngoscopes and the Macintosh laryngoscope in patients with a simulated difficult airway: a randomised, controlled trial.

This prospective randomised, controlled trial compares the performance of three unchannelled videolaryngoscopes (KingVision™ , Airtraq™ , A.P. Advance™ MAC) and the standard Macintosh laryngoscope. With ethics committee approval and written informed consent, 480 patients were included. A difficult airway was created with a cervical collar, limiting mouth opening and neck movement. Primary outcome was first-attempt orotracheal intubation success. Overall success, laryngeal view, intubation difficulty scale, handling, intubation times and side-effects were secondary outcomes. First-attempt success rates were: KingVision 90% (95% CI 83-94%), Airtraq 82% (74-88%), A.P. Advance MAC 49% (40-58%), Macintosh 44% (35-53%; p < 0.001). The 95% confidence interval of first-attempt success rate was thus below 90% for all devices, but the KingVision and the Airtraq performed better than the A.P. Advance MAC and the Macintosh laryngoscope. Also, performance was better with the KingVision and the Airtraq in terms of overall success, laryngeal view, intubation difficulty scale and quality of view. Problems with tube advancement were a frequent cause of intubation failure. In summary, the KingVision and the Airtraq performed better than the A.P. Advance MAC and the Macintosh laryngoscope. Success rates of the unchannelled KingVision and Airtraq were similar to those of their channelled versions reported previously, indicating that performance largely depends on blade design rather than the presence of a channel for tube advancement.

The performance of rigid scopes for tracheal intubation: a randomised, controlled trial in patients with a simulated difficult airway.

We compared the Bonfils™ and SensaScope™ rigid fibreoptic scopes in 200 patients with a simulated difficult airway randomised to one of the two devices. A cervical collar inhibited neck movement and reduced mouth opening to a mean (SD) of 23 (3) mm. The primary outcome parameter was overall success of tracheal intubation; secondary outcomes included first-attempt success, intubation times, difficulty of intubation, fibreoptic view and side-effects. The mean (95% CI) overall success rate was 88 (80-94)% for the Bonfils and 89 (81-94)% for the SensaScope (p = 0.83). First-attempt intubation success rates were 63 (53-72)% for the Bonfils and 72 (62-81)% for the SensaScope (p = 0.17). Median (IQR [range]) intubation time was significantly shorter with the SensaScope (34 (20-84 [5-240]) s vs. 45 (25-134 [12-230]) s), and fibreoptic view was significantly better with the SensaScope (full view of the glottis in 79% with the SensaScope vs. 61% with the Bonfils). This might be explained by its steerable tip and the S-formed shape, contributing to better manoeuvrability. There were no differences in the difficulty of intubation or side-effects.

Evaluation of six videolaryngoscopes in 720 patients with a simulated difficult airway: a multicentre randomized controlled trial.

BACKGROUND: Videolaryngoscopes are aggressively marketed, but independent evaluation in difficult airways is scarce. This multicentre, prospective randomized controlled trial evaluates six videolaryngoscopes in patients with a simulated difficult airway. METHODS: With ethics committee approval and written informed consent, 12 senior anaesthetists intubated the trachea of 720 patients. A cervical collar limited mouth opening and neck movement, making intubation difficult. We evaluated three unchannelled (C-MAC™ D-blade, GlideScope™, and McGrath™) and three channelled videolaryngoscopes (Airtraq™, A.P. Advance™ difficult airway blade, and KingVision™). The primary outcome was first-attempt intubation success rate. Secondary outcomes included overall success rate, laryngeal view, intubation times, and side-effects. The primary hypothesis for every videolaryngoscope was that the 95% confidence interval of first-attempt success rate is ≥90%. RESULTS: Mouth opening was decreased from 46 (sd 7) to 23 (3) mm with the cervical collar. First-attempt success rates were 98% (McGrath™), 95% (C-MAC™ D-blade), 87% (KingVision™), 85% (GlideScope™ and Airtraq™), and 37% (A.P. Advance™, P<0.01). The 95% confidence interval of first-attempt success rate was >90% only for the McGrath™. Overall success, laryngeal view, and intubation times differed significantly between videolaryngoscopes (all P<0.01). Side-effects were minor. CONCLUSIONS: This trial revealed differences in the performance of six videolaryngoscopes in 720 patients with restricted neck movement and limited mouth opening. In this setting, first-attempt success rates were 85-98%, except for the A.P. Advance™ difficult airway blade. Highest success and lowest tissue trauma rates were achieved by the McGrath™ and C-MAC™ D-blade, highlighting the importance of the videolaryngoscope blade design. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov: identifier NCT01692535.

Rendimiento e impacto de los primeros respondedores en la evolución de la medicina de emergencias prehospitalaria en Suiza / Comparing performance and impact of first responders on outcome in prehospital emergency medicine in Switzerland

Introducción: Existen resultados contradictorios sobre la eficacia de los primeros respondedores en emergencias extrahospitalarias. Este estudio evalúa el rendimiento y el impacto de estos profesionales en el resultado. Método: Es un estudio de cohortes retrospectivo donde se evalúa la precisión de los médicos de emergencia, paramédicos y médicos generales. Se comparó el diagnóstico realizado en la situación de emergencia prehospitalaria frente al diagnóstico al alta del hospital. El resultado primario fue el impacto de la precisión del diagnóstico sobre la mortalidad. Los resultados secundarios fueron: 1) tiempo en la escena, y 2) duración de la hospitalización. Se valoró especialmente la influencia de la experiencia clínica y de la formación de postgrado. Resultados: Se evaluaron 1.241 diagnósticos. Los pacientes ingresados con el diagnóstico incorrecto o sin diagnóstico mostraron un mayor riesgo de mortalidad (p = 0,04,OR 1,9, IC 1,04-3,34). El tiempo en la escena y el tiempo de ingreso hospitalario fue menor si el diagnóstico fue el correcto. Los médicos de emergencias, paramédicos y médicos generalistas diagnostican con una precisión comparable (p = 0,139), pero en el caso de los médicos de emergencias se demostró un aumento significativo de la precisión en relación a sus años de experiencia (p < 0,001). Después de 6 años de experiencia, alcanzan una precisión diagnóstica mayor del 90%. Este efecto no se pudo demostrar en paramédicos ni en médicos generales. Conclusión: El diagnóstico prehospitalario correcto reduce la mortalidad y la estancia hospitalaria. Los médicos formados en emergencias tienen una nivel de precisión diagnóstica mayor. Por lo tanto, estos médicos deben ser incluidos en el sistema de emergencias prehospitalarias, sobre todo para los casos más graves (AU)

Background: Contradictory results are reported in the medical literature on effectiveness of first responders inprehospital emergency medicine. In this study we evaluated responders performance and impact on outcome. Methods: In a retrospective cohort study we evaluated the accuracy of diagnoses by emergency physicians, paramedics, and general practitioners. We compared the diagnosis made in the prehospital emergency situation to the diagnosis at discharge from the hospital. Primary outcome was the impact of accuracy of diagnosis on mortality. Secondary outcomes were, 1) time on scene, 2) duration of hospitalization. The influence of clinical experience and postgraduate training on accuracy of diagnoses was of particular interest. Results: We evaluated 1241 diagnoses. Patients admitted with a wrong or missing diagnosis showed an increased mortality risk (P = 0.04, OR 1.9; CI 1.04-3.34). The time spent on scene and the duration of his/her hospital stay was shorter if the diagnosis was correct. Emergency physicians, paramedics and general practitioners made diagnoses with comparable accuracy (P = 0.139) but emergency physicians showed a significant increase in accuracy correlated to their years of clinical experience (P < 0.001). After postgraduate year six they reached a level of diagnostic accuracy > 90%.This effect could not be shown for paramedics or general practitioners. Conclusion: A correct diagnosis in prehospital emergency medicine reduces mortality and length of hospital stay. Trained emergency physicians make diagnoses with a high degree of accuracy. Therefore, they should be increasingly integrated into prehospital emergency medicine, particularly for more severe cases (AU)

Survey on controversies in airway management among anesthesiologists in the UK, Austria and Switzerland.

BACKGROUND: While surveys about anesthesia practice appear regularly in the anesthesia literature, they are usually bound to one country. We compared the approach to specific airway management issues among anesthesiologists from three different European countries. METHODS: A questionnaire was distributed during the main session of three anesthesia meetings in Austria (A), the UK, and Switzerland (CH). Questions concerned whether anesthesiologists routinely check for risk factors associated with difficult mask ventilation; whether anesthesiologists are used to mask ventilate prior to administering neuromuscular blocking drugs (NMBD); whether anesthesiologists apply cricoid pressure. RESULTS: We evaluated 266 questionnaires. No significant differences in the frequency of checking predictors were found, except for "age" (UK: 28%, A: 13%, CH:11%, P=0.01). Fewer anesthesiologists from the UK always check mask ventilation before NMBD (UK: 34%, A: 72%, CH: 67%, P<0.001); but they check mask ventilation more often when risk factors are present (UK: 36%, A: 13%, CH: 20%, P=0.004). Very few anesthesiologists from the UK never apply cricoid pressure (UK: 2%, A: 40%, CH: 49%, P<0.001), but almost all of them apply it in case of rapid sequence intubation (UK: 96%, A: 52%, CH:30%, P<0.001). CONCLUSION: Answers from anesthesiologists in the UK differed significantly from those in A and CH. Anesthesiologists in the UK check mask ventilation after induction less frequently, but they check more often when risk factors of difficult mask ventilation are present. Cricoid pressure seems to remain an important part of the rapid sequence induction technique in the UK, whereas anesthesiologists in Austria and Switzerland rely less on this technique.

i-gel™ supraglottic airway in clinical practice: a prospective observational multicentre study.

BACKGROUND: The i-gel™ supraglottic airway device has been studied in randomized controlled studies, but it has not been evaluated in a large prospective patient cohort. Therefore, we performed this prospective multicentre observational study to evaluate success rates, airway leak pressure, risk factors for i-gel failure, and adverse events. METHODS: With Ethics Committee approval and waiver of patients' consent, data about anaesthesia providers, patient characteristics, and the performance of the i-gel were recorded in five independent hospitals in Switzerland over a period of 24 months. We analysed success rates, leak pressures, adverse events, and risk factors for failure. RESULTS: Data from 2049 i-gel uses were analysed. Patients' mean age was 47 (range 6-91) yr. The primary i-gel success rate without changing size was 93%; the overall success rate was 96%. Insertion was deemed very easy or easy in 92%. The mean airway leak pressure was 26 (8) cm H(2)O. The mean anaesthesia time was 67 (42) min. Risk factors associated with i-gel failure were males (P<0.001), impaired mandibular subluxation (P=0.01), poor dentition (P=0.02), and older age (P<0.01). Adverse events recorded were laryngeal spasms (n=25, 1.2%), blood stained airway devices (n=79, 3.9%), transient nerve damage (n=2, 0.1%), one case of transient vasovagal asystole, and one glottic haematoma. CONCLUSIONS: The i-gel is a reliable supraglottic airway device failing in <5% and providing high airway leak pressures. Males, impaired mandibular subluxation, poor dentition, and older age are risk factors associated with primary device failure. Serious adverse events are rare.

Standard vs. point-of-care measurement of fibrinogen: potential impact on clinical decisions.

BACKGROUND: Intraoperative major bleeding is a common complication during surgery and can lead to the transfusion of blood products and/or procoagulant drugs. This is a therapeutic challenge, and adherence to guidelines is desirable to preserve blood product resources. The intraoperative administration of fibrinogen concentrate, a pro-coagulant drug, in bleeding patients might reduce the use and therefore the risks associated with blood products. METHODS: In this observational pilot study we determined whether fibrinogen measured by point-of-care thromboelastometry (Rotem®, fibtem-test) would lead to a similar therapeutical decision concerning the administration of fibrinogen concentrate when compared to the standard method (Clauss). RESULTS: Blood samples of 36 patients undergoing major surgery were simultaneously analyzed using both methods. According to the cutoff values of current guidelines based on the standard method, no patient would receive fibrinogen concentrate. In comparison, if point-of-care thromboelastometry were used and its cutoff for fibrinogen applied, 16 patients (44%, P<0.001) would receive fibrinogen concentrate. CONCLUSION: The method used for intraoperative coagulation monitoring has a major impact on therapeutic decisions concerning the use of blood products and/or pro-coagulant drugs. If fibrinogen was measured by point-of-care thromboelastometry instead of the standard method according to Clauss, the use of fibrinogen concentrate would increase significantly and less fresh frozen plasma would be administered.