Carbon dioxide and cardiac output as major contributors to cerebral oxygenation during apnoeic oxygenation

Apnoeic oxygenation has experienced a resurgence in interest in critical care and perioperative medicine. However, its effect on cerebral oxygenation and factors influencing it, have not yet been investigated in detail. By using near-infrared spectroscopy, we intended to provide further evidence for the safety of apnoeic oxygenation and to increase our understanding of the association between cerebral perfusion, haemodynamic, respiratory and demographic factors. In this secondary analysis of a prospective randomized controlled noninferiority trial, we recruited 125 patients, who underwent surgery under general anaesthesia with neuromuscular blockade. Arterial blood samples were taken every 2 min for a total of 15 min under apnoeic oxygenation with 100% oxygen. Near-infrared spectroscopy and cardiac output were continuously measured. Statistical analysis was performed using uni- and multivariable statistics. Ninety-one complete data sets were analysed. In six patients the SpO2 fell below 92% (predefined study termination criterion). The significant average increase of cerebral oxygenation was 0.5%/min and 2.1 mmHg/min for the arterial pressure of carbon dioxide (paCO2). The median cardiac output increased significantly from 5.0 l/min (IQR 4.5-6.0) to 6.5 l/min (IQR 5.7-7.5). The most significant effect on cerebral oxygenation was exhibited by the variable paCO2 and non-specific patient factors, followed by cardiac output and paO2. Apnoeic oxygenation proves to have a high safety profile while significantly increasing cerebral oxygenation, paCO2 and cardiac output. In reverse, NIRS might act as a reliable clinical surrogate of paCO2 and cardiac output during stable arterial oxygenation.

Propofol sedation in routine endoscopy: A case series comparing target controlled infusion vs manually controlled bolus concept

BACKGROUND

Many studies have addressed safety and effectiveness of non-anaesthesiologist propofol sedation (NAPS) for gastrointestinal (GI) endoscopy Target controlled infusion (TCI) is claimed to provide an optimal sedation regimen by avoiding under- or oversedation.

AIM

To assess safety and performance of propofol TCI sedation in comparison with nurse-administered bolus-sedation.

METHODS

Fouty-five patients undergoing endoscopy under TCI propofol sedation were prospectively included from November 2016 to May 2017 and compared to 87 patients retrospectively included that underwent endoscopy with NAPS. Patients were matched for age and endoscopic procedure. We recorded time of sedation and endoscopy, dosage of medication and adverse events.

RESULTS

There was a significant reduction in dose per time of propofol administered in the TCI group, compared to the NAPS group (8.2 ± 2.7 mg/min vs 9.3 ± 3.4 mg/min; P = 0.046). The time needed to provide adequate sedation levels was slightly but significantly lower in the control group (5.3 ± 2.7 min vs 7.7 ± 3.3 min; P < 0.001), nonetheless the total endoscopy time was similar in both groups. No differences between TCI and bolus-sedation was observed for mean total-dosage of propofol rate as well as adverse events.

CONCLUSION

This study indicates that sedation using TCI for GI endoscopy reduces the dose of propofol necessary per minute of endoscopy. This may translate into less adverse events. However, further and randomized trials need to confirm this trend.

Limitations of transcutaneous carbon dioxide monitoring in apneic oxygenation

BACKGROUND

High-flow nasal oxygenation is increasingly used during sedation procedures and general anesthesia in apneic patients. Transcutaneous CO2 (ptcCO2)-monitoring is used to monitor hypercapnia. This study investigated ptcCO2-monitoring during apneic oxygenation.

METHODS

We included 100 patients scheduled for elective surgery under general anesthesia in this secondary analysis of a randomized controlled trial. Before surgery, we collected ptcCO2 measured by TCM4 and TCM5 monitors and arterial blood gas (ABG) measurements every two minutes during 15 minutes of apnea. Bland-Altman plots analyzed agreement between measurement slopes; linear mixed models estimated the different measuring method effect, and outlined differences in slope and offset between transcutaneous and arterial CO2 partial pressures.

RESULTS

Bland-Altman plots showed a bias in slope (95% confidence intervals) between ABG and TCM4-measurements of 0.05mmHg/min (-0.05 to 0.15), and limits of agreement were -0.88mmHg/min (-1.06 to -0.70) and 0.98mmHg/min (0.81 to 1.16). Bias between ABG and TCM5 was -0.14mmHg/min (-0.23 to -0.04), and limits of agreement were -0.98mmHg/min (-1.14 to -0.83) and 0.71mmHg/min (0.55 to 0.87). A linear mixed model (predicting the CO2-values) showed an offset between arterial and transcutaneous measurements of TCM4 (-15.2mmHg, 95%CI: -16.3 to -14.2) and TCM5 (-19.1mmHg, -20.1 to -18.0). Differences between the two transcutaneous measurements were statistically significant.

CONCLUSIONS

Substantial differences were found between the two transcutaneous measurement systems, and between them and ABG. Transcutaneous CO2 monitoring cannot replace arterial CO2-monitoring during apneic oxygenation. In clinical settings with rapidly changing CO2-values, arterial blood gas measurements are needed to reliably assess the CO2-partial pressure in blood.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT03478774).

Risk patterns of consecutive adverse events in airway management: a Bayesian network analysis

BACKGROUND

Minor adverse airway events play a pivotal role in the safety of airway management. Changes in airway management strategies can reduce such events, but the broader impact on airway management remains unclear.

METHODS

Minor, frequently occurring adverse airway events were audited before and after implementation of changes to airway management strategies. We used two Bayesian networks to examine conditional probabilities of subsequent airway events and to compute the likelihood of certain events given that certain previous events occurred.

RESULTS

Independent of sex, age, and American Society of Anesthesiologists physical status, targeted changes to airway management strategies reduced the risk of a first event. Obese patients were an exception, in whom no risk reduction was achieved. Frequently occurring event sequences were identified, for example the most likely event to follow difficult bag-mask ventilation was a Cormack-Lehane grade ≥3, with a risk of 14.3% (95% credible interval [CI], 11.4-17.2%). An impact of the targeted changes was detected on the likelihood of some event sequences, for example the likelihood of no consecutive event after a tracheal tube-related event increased from 43.3% (95% CI, 39.4-47.6%) to 56.4% (95% CI, 52.0-60.5%).

CONCLUSIONS

Identification of risk patterns and typical structures of event sequences provides a clinically relevant perspective on airway incidents. It further provides a means to quantify the impact of targeted airway management changes. These targeted changes can influence some event sequences, but overall, the benefit results from the cumulative effect of improvements in multiple events. Targeted airway management changes with knowledge of risk patterns and event sequences can potentially further improve patient safety in airway management.

CLINICAL TRIAL REGISTRATION

NCT02743767.

Direct versus video laryngoscopy with standard blades for neonatal and infant tracheal intubation with supplemental oxygen: a multicentre, non-inferiority, randomised controlled trial

BACKGROUND

Tracheal intubation in neonates and infants is a potentially life-saving procedure. Video laryngoscopy has been found to improve first-attempt tracheal intubation success and reduce complications compared with direct laryngoscopy in children younger than 12 months. Supplemental periprocedural oxygen might increase the likelihood of successful first-attempt intubation because of an increase in safe apnoea time. We tested the hypothesis that direct laryngoscopy is not inferior to video laryngoscopy when using standard blades and supplemental oxygen is provided.

METHODS

We did a non-inferiority, international, multicentre, single-blinded, randomised controlled trial, in which we randomly assigned neonates and infants aged up to 52 weeks postmenstrual age scheduled for elective tracheal intubation to either direct laryngoscopy or video laryngoscopy (1:1 ratio, randomly assigned using a secure online service) at seven tertiary paediatric hospitals across Australia, Canada, Italy, Switzerland, and the USA. An expected difficult intubation was the main exclusion criteria. Parents and patients were masked to the assigned group of treatment. All infants received supplemental oxygen (1 L/Kg per min) during laryngoscopy until the correct tracheal tube position was confirmed. The primary outcome was the proportion of first-attempt tracheal intubation success, defined as appearance of end-tidal CO2 curve at the anaesthesia monitor, between the two groups in the modified intention-to-treat analysis. A 10% non-inferiority margin between direct laryngoscopy or video laryngoscopy was applied. The trial is registered with ClinicalTrials.gov (NCT04295902) and is now concluded.

FINDINGS

Of 599 patients assessed, 250 patients were included between Oct 26, 2020, and March 11, 2022. 244 patients were included in the final modified intention-to-treat analysis. The median postmenstrual age on the day of intubation was 44·0 weeks (IQR 41·0-48·0) in the direct laryngoscopy group and 46·0 weeks (42·0-49·0) in the video laryngoscopy group, 34 (28%) were female in the direct laryngoscopy group and 38 (31%) were female in the video laryngoscopy group. First-attempt tracheal intubation success rate with no desaturation was higher with video laryngoscopy (89·3% [95% CI 83·7 to 94·8]; n=108/121) compared with direct laryngoscopy (78·9% [71·6 to 86·1]; n=97/123), with an adjusted absolute risk difference of 9·5% (0·8 to 18·1; p=0·033). The incidence of adverse events between the two groups was similar (-2·5% [95% CI -9·6 to 4·6]; p=0·490). Post-anaesthesia complications occurred seven times in six patients with no difference between the groups.

INTERPRETATION

Video laryngoscopy with standard blades in combination with supplemental oxygen in neonates and infants might increase the success rate of first-attempt tracheal intubation, when compared with direct laryngoscopy with supplemental oxygen. The incidence of hypoxaemia increased with the number of attempts, but was similar between video laryngoscopy and direct laryngoscopy. Video laryngoscopy with oxygen should be considered as the technique of choice when neonates and infants are intubated.

FUNDING

Swiss Pediatric Anaesthesia Society, Swiss Society for Anaesthesia and Perioperative Medicine, Foundation for Research in Anaesthesiology and Intensive Care Medicine, Channel 7 Telethon Trust, Stan Perron Charitable Foundation, National Health and Medical Research Council.

Team leadership assessment after advanced life support courses comparing real teams vs. simulated teams

Aim

Effective team leadership is essential during cardiopulmonary resuscitation (CPR) and is taught during international advanced life support (ALS) courses. This study compared the judgement of team leadership during summative assessments after those courses using different validated assessment tools while comparing two different summative assessment methods.

Methods

After ALS courses, twenty videos of simulated team assessments and 20 videos of real team assessments were evaluated and compared. Simulated team assessment used an instructor miming a whole team, whereas real team assessment used course participants as a team that acted on the team leader's commands. Three examiners individually evaluated each video on four different validated team leadership assessment tools and on the original European Resuscitation Council's (ERC) scenario test assessment form which does not assess leadership. The primary outcome was the average performance summary score between all three examiners for each assessment method.

Results

The average performance summary score for each of the four assessment tools was significantly higher for real team assessments compared to simulated team assessments (all p-values < 0.01). The summary score of the ERC's scenario test assessment form was comparable between both assessment methods (p = 0.569), meaning that participants of both assessments performed equally.

Conclusion

Team leadership performance is rated significantly higher in real team summative assessments after ALS courses compared to simulated team assessments by four leadership assessment tools but not by the standard ERC's scenario test assessment form. These results suggest that summative assessments in ALS courses should integrate real team assessments, and a new assessment tool including an assessment of leadership skills needs to be developed.

Assessment of Human Factors After Advanced Life Support Courses Comparing Simulated Team and Real Team Assessment: A Randomized Controlled Cohort Trial

Aim

Human factors are essential for high-quality resuscitation team collaboration and are, therefore, taught in international advanced life support courses, but their assessment differs widely. In Europe, the summative life support course assessment tests mainly adhere to guidelines but few human factors. This randomized controlled simulation trial investigated instructors’ and course participants’ perceptions of human factors assessment after two different summative assessments.

Methods

All 5th/6th-year medical students who attended 19 advanced life support courses according to the 2015 European Resuscitation Council guidelines during one study year were invited to participate. Each course was randomized to either: (1) Simulated team assessment (one instructor simulates a team, and the assessed person leads this “team” through a cardiac-arrest scenario test); (2) Real team assessment (4 students form a team, one of them is assessed as the team leader; team members are not assessed and act only on team leader’s commands). After the summative assessments, instructors, and students rated the tests’ ability to assess human factors using a visual analog scale (VAS, 0 = no agreement, 10 = total agreement).

Results

A total of 227 students participated in the 1-day Immediate Life Support courses, 196 students in the 2-day Advanced Life Support courses, additionally 54 instructors were included. Instructors judged all human factors significantly better in real team assessments; students rated leadership and situational awareness comparable between both assessments. Assessment pass rates were comparable between groups.

Conclusion

Summative assessment in real teams was perceived significantly better to assess human factors. These results might influence current summative assessment practices in advanced life support courses.

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.

Airway management in a Helicopter Emergency Medical Service (HEMS): a retrospective observational study of 365 out-of-hospital intubations

Background

Airway management is a key skill in any helicopter emergency medical service (HEMS). Intubation is successful less often than in the hospital, and alternative forms of airway management are more often needed.

Methods

Retrospective observational cohort study in an anaesthesiologist-staffed HEMS in Switzerland. Patient charts were analysed for all calls to the scene (n = 9,035) taking place between June 2016 and May 2017 (12 months). The primary outcome parameter was intubation success rate. Secondary parameters included the number of alternative techniques that eventually secured the airway, and comparison of patients with and without difficulties in airway management.

Results

A total of 365 patients receiving invasive ventilatory support were identified. Difficulties in airway management occurred in 26 patients (7.1%). Severe traumatic brain injury was the most common indication for out-of-hospital Intubation (n = 130, 36%). Airway management was performed by 129 different Rega physicians and 47 different Rega paramedics. Paramedics were involved in out-of-hospital airway manoeuvres significantly more often than physicians: median 7 (IQR 4 to 9) versus 2 (IQR 1 to 4), p < 0.001.

Conclusion

Despite high overall success rates for endotracheal intubation in the physician-staffed service, individual physicians get only limited real-life experience with advanced airway management in the field. This highlights the importance of solid basic competence in a discipline such as anaesthesiology.

Dexmedetomidine versus Propofol for Operator-Directed Nurse-Administered Procedural Sedation during Catheter Ablation of Atrial Fibrillation: a Randomized Controlled Study

BACKGROUND

Operator-directed nurse-administered (ODNA) sedation with propofol is the preferred sedation technique for catheter ablation of atrial fibrillation (AF) in many centers.

OBJECTIVE

We aimed to investigate whether Dexmedetomidine, an α2-adrenergic receptor agonist, is superior to propofol.

METHODS

We randomized 160 consecutive patients undergoing first AF ablation to ODNA sedation by dexmedetomidine (DEX group) versus propofol (PRO group), according to a standardized protocol. Patients were unaware of treatment allocation. The primary endpoint was a composite of inefficient sedation, termination/change of sedation protocol or procedure abortion, hypercapnia (transcutaneous CO2 >55 mmHg), hypoxemia (SpO₂ <90%) or intubation, prolonged hypotension (systolic blood pressure <80 mmHg), and sustained bradycardia necessitating cardiac pacing. Secondary endpoints were the components of the primary endpoint and patient satisfaction with procedural sedation, as assessed by a standardized questionnaire the day following ablation.

RESULTS

The primary endpoint occurred in 15 DEX group and 25 PRO group patients (19% vs. 31%; p=0.068). Hypercapnia was significantly more frequent in PRO group patients (29% vs. 10%; p=0.003). There was no significant difference among the other components of the primary endpoint, no procedure was aborted. Patient satisfaction was significantly better in PRO group patients (visual analog scale 0-100; median 100 in PRO group vs. median 93 in DEX group; p<0.001).

CONCLUSION

Efficacy of ODNA sedation with dexmedetomidine was not different to propofol. Hypercapnia occurs less frequent with dexmedetomidine, but patient satisfaction is better with propofol sedation. In selected patients, dexmedetomidine may be used as an alternative to propofol for ODNA sedation during AF ablation. (ClinicalTrials.gov number NCT03844841).

Optimisation of airway management strategies: a prospective before-and-after study on events related to airway management

BACKGROUND

Poor medical outcomes often result from series of minor events. The present study assessed events related to airway management to determine whether targeted changes to departmental strategies for airway management can reduce the incidence.

METHODS

This prospective before-and-after study was performed with ethics committee approval and written informed consent from patients. Major and minor events related to airway management were prospectively recorded for 9 weeks. After implementation of changes to departmental strategies for airway management, events were again prospectively recorded over 9 weeks. Primary outcome was number of cases with events. Secondary outcomes were various predefined events.

RESULTS

At study baseline, 3668 cases and at follow-up 3786 cases were assessed. Cases with events decreased from 566 (15.4%) to 433 (11.4%) (risk ratio [RR]=0.74; 95% confidence interval [CI], 0.66-0.83; P<0.01). As secondary outcomes, the following events decreased: Cormack-Lehane grade 3 or 4 (4.3-2.9%; RR=0.67; 95% CI, 0.52-0.85; P<0.01); difficult bag-mask ventilation (3.8-2.7%; RR=0.69; 95% CI, 0.54-0.89; P<0.01); hypoxaemia (3.8-2.9%; RR=0.75; 95% CI, 0.59-0.96; P=0.03); unplanned use of special equipment (3.2-2.0%; RR=0.62; (95% CI, 0.47-0.83; P<0.01); oesophageal intubation (1.3-0.8%; RR=0.61; 95% CI, 0.39-0.96; P=0.03); bleeding (0.8-0.2%; RR=0.30; 95% CI, 0.14-0.63; P<0.01); insufficient spontaneous breathing (0.3-0.0%; RR=0.09; 95% CI, 0.01-0.68; P<0.01); communication errors (0.1-0.0%; RR=0; 95% CI, 0-NA; P=0.03).

CONCLUSIONS

Implementation of changes to departmental strategies for airway management significantly reduced cases with events related to airway management. Analysis of events and implementation of strategies that specifically target identified issues might be key to improving airway management.

CLINICAL TRIAL REGISTRATION

NCT02743767.

Survival and long-term outcomes following in-hospital cardiac arrest in a Swiss university hospital: a prospective observational study

Background

Incidence of in-hospital cardiac arrest is reported to be 0.8 to 4.6 per 1,000 patient admissions. Patient survival to hospital discharge with favourable functional and neurological status is around 21–30%. The Bern University Hospital is a tertiary medical centre in Switzerland with a cardiac arrest team that is available 24 h per day, 7 days per week. Due to lack of central documentation of cardiac arrest team interventions, the incidence, outcomes and survival rates of cardiac arrests in the hospital are unknown. Our aim was to record all cardiac arrest team interventions over 1 year, and to analyse the outcome and survival rates of adult patients after in-hospital cardiac arrests.

Methods

We conducted a prospective single-centre observational study that recorded all adult in-hospital cardiac arrest team interventions over 1 year, using an Utstein-style case report form. The primary outcome was 30-day survival after in-hospital cardiac arrest. Secondary outcomes were return of spontaneous circulation, neurological status (after return of spontaneous circulation, after 24 h, after 30 days, after 1 and 5 years), according to the Glasgow Outcomes Scale, and functional status at 30 days and 1 year, according to the Short-form-12 Health Survey.

Results

The cardiac arrest team had 146 interventions over the study year, which included 60 non-life-threatening alarms (41.1%). The remaining 86 (58.9%) acute life-threatening situations included 68 (79.1%) as patients with cardiac arrest. The mean age of these cardiac arrest patients was 68 ± 13 years, with a male predominance (51/68; 75.0%). Return of spontaneous circulation was recorded in 49 patients (72.1%). Over one-third of the cardiac arrest patients (27/68) were alive after 30 days with favourable neurological outcome. The patients who survived the first year lived also to 5 years after the event with favourable neurological and functional status.

Conclusions

The in-hospital cardiac arrest incidence on a large tertiary Swiss university hospital was 1.56 per 1000 patient admissions. After a cardiac arrest, about a third of the patients survived to 5 years with favourable neurological and functional status. Alarms unrelated to life-threatening situations are common and need to be taken into count within a low-threshold alarming system.

Trial Registration: The trial was registered in clinicaltrials.gov (NCT02746640).

Supplementary Information

The online version contains supplementary material available at 10.1186/s13049-021-00931-0.

The effective group size for teaching cardiopulmonary resuscitation skills - A randomized controlled simulation trial

AIM OF THE STUDY

The ideal group size for effective teaching of cardiopulmonary resuscitation is currently under debate. The upper limit is reached when instructors are unable to correct participants' errors during skills practice. This simulation study aimed to define this limit during cardiopulmonary resuscitation teaching.

METHODS

Medical students acting as simulated Basic Life Support course participants were instructed to make three different pre-defined Basic Life Support quality errors (e.g., chest compression too fast) in 7 min. Basic Life Support instructors were randomized to groups of 3-10 participants. Instructors were asked to observe the Basic Life Support skills and to correct performance errors. Primary outcome was the maximum group size at which the percentage of correctly identified participants' errors drops below 80%.

RESULTS

Sixty-four instructors participated, eight for each group size. Their average age was 41 ± 9 years and 33% were female, with a median [25th percentile; 75th percentile] teaching experience of 6 [2;11] years. Instructors had taught 3 [1;5] cardiopulmonary resuscitation courses in the year before the study. A logistic binominal regression model showed that the predicted mean percentage of correctly identified participants' errors dropped below 80% for group sizes larger than six.

CONCLUSION

This randomized controlled simulation trial reveals decreased ability of instructors to detect Basic Life Support performance errors with increased group size. The maximum group size enabling Basic Life Support instructors to correct more than 80% of errors is six. We therefore recommend a maximum instructor-to-participant ratio of 1:6 for cardiopulmonary resuscitation courses.

Simulation-based medical education for Ambulance Jet and Helicopter Emergency Medical Services: A program description and evaluation

This article was migrated. The article was marked as recommended. Introduction: In aviation, crew resource management trainings are established methods to enhance safety, a method that also gained popularity in medicine. In 2015, the Swiss Air Rescue (Rega) Helicopter Emergency Medical Services decided to start a simulation-based medical education program for its helicopter and ambulance jet crews (emergency physicians, paramedics/flight nurses and pilots). The aim of this program was to improve technical skills and the application of human factors during rescue missions. This report shows a five-year summary of the participants' course evaluation. Methods: A 1-day high-fidelity simulation on crisis resource management with video-assisted debriefing took place at 3 centres, two in Switzerland; one in Germany. Crew members participated once per year. Simulation covered critical situations in the helicopter or jet, during handovers at an intensive care unit or in ambulances. Extra Corporeal Membrane Oxygenation and Intra-Aortic Balloon Pump use was simulated during helicopter transports. Additionally, four times per year flight crews rehearsed basic and advanced life support skills using low-fidelity equipment between missions. Participants answered an anonymized course evaluation survey. Answers were rated on a Numeric Rating Scale ranging from 1=no agreement to 5=total agreement. Results: 329 participated and answered the questionnaire; 50% were emergency physicians, 40% paramedics, 9% flight nurses, and 1% pilots. Participants agreed that the course taught competencies that were useful for their clinical practice. However, confidence to apply Extra Corporeal Membrane Oxygenation or Intra-Aortic Balloon Pump skills was significantly lower compared to other emergency competencies. Instructors were rated as experienced, engaged and motivated, as well as responsive to course participants. Conclusions: This simulation-based medical education program, with the goal to increase patient's safety and outcome, was launched successfully. Participants especially valued the time to reflect on clinical performance as well as on crew interaction and ways to apply human factors to improve their team performance and task management.

Analysis of tracheal intubation in out-of-hospital helicopter emergency medicine recorded by video laryngoscopy

Background

Tracheal intubation remains the gold standard of airway management in emergency medicine and maximizing safety, intubation success, and especially first-pass intubation success (FPS) in these situations is imperative.

Methods

We conducted a prospective observational study on all 12 helicopter emergency medical service (HEMS) bases of the Swiss Air Rescue, between February 15, 2018, and February 14, 2019. All 428 patients on whom out-of-hospital advanced airway management was performed by the HEMS crew were included. The C-MAC video laryngoscope was used as the primary device for tracheal intubation. Intubation procedures were recorded by the video laryngoscope and precise time points were recorded to verify the time necessary for each attempt and the overall procedure time until successful intubation. The videos were further analysed for problems and complications during airway management by an independent reviewer. Additionally, a questionnaire about the intubation procedure, basic characteristics of the patient, circumstances, environmental factors, and the provider’s level of experience in airway management was filled out. Main outcome measures were FPS of tracheal intubation, overall success rate, overall intubation time, problems and complications of video laryngoscopy.

Results

FPS rate was 87.6% and overall success rate 98.6%. Success rates, overall time to intubation, and subjective difficulty were not associated to the providers’ expertise in airway management. In patients undergoing CPR FPS was 84.8%, in trauma patients 86.4% and in non-trauma patients 93.3%. FPS in patients with difficult airway characteristics, facial trauma/burns or obesity ranges between 87 and 89%. Performing airway management indoors or inside an ambulance resulted in a significantly higher FPS of 91.1% compared to outdoor locations (p < 0.001). Direct solar irradiation on the screen, fogging of the lens, and blood on the camera significantly impaired FPS. Several issues for further improvements in the use of video laryngoscopy in the out-of-hospital setting and for quality control in airway management were identified.

Conclusion

Airway management using the C-MAC video laryngoscope with Macintosh blade in a group of operators with mixed experience showed high FPS and overall rates of intubation success. Video recording emergency intubations may improve education and quality control.

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.

Prospective observational study evaluating the C-MAC Video Stylet for awake tracheal intubation: a single-center study

BACKGROUND

Gold standard for management of known or predicted difficult airways is awake tracheal intubation. The newly developed C-MAC Video Stylet promises to combine the advantages of rigid stylets and flexible optical scopes. We therefore evaluated the feasibility of awake orotracheal intubations with this device.

METHODS

In this prospective observational study, three anesthesiologists experienced in advanced airway management performed each 12 awake oral intubations with this device on adult patients with known or predicted intubation difficulties. The primary outcome was overall intubation success. Secondary outcomes were total attempts, successful time, first post-operative day sequelae, and subjective intubation difficulty rated on a visual analogue scale (1, very easy; 10, extremely difficult).

RESULTS

Ten (28%) patients were female, aged 64 +/-13 years, with BMI 26 +/- 5 kg.m- 1. ASA status (II/III/IV) was 8 (22%) /, 23 (64%) / 5 (14%). Indications for awake oral intubation were: oropharyngeal tumor 20 (56%), cervical-spine fracture 8 (22%), previously known difficult airway 4 (11%), spinal canal stenosis 3 (8%), and bilateral peritonsillar abscess 1 (3%). Overall 97% were successfully intubated in 45 s (31-88). First-attempt success rate was 80% in 37 s (29-54); 92% of patients would choose the same procedure again. On the first post-operative day, 11 (31%) patients complained of sore throat; 5 (14%) had minor injuries. Ease of intubation was rated as median VAS (IQR) 3 (1-7).

CONCLUSIONS

The new C-MAC Video Stylet has the potential to serve as a suitable device for visualized oral awake intubation in difficult airway situations.

Nasal nalbuphine analgesia in prehospital trauma managed by first-responder personnel on ski slopes in Switzerland: an observational cohort study

BACKGROUND

Pain is one of the major symptoms complained about by patients in the prehospital setting, especially in the case of trauma. When there is mountainous topography, as in Switzerland, there may be a time delay between injury and arrival of professional rescuers, in particular on ski slopes. Administration of a safe opioid by first responders may improve overall treatment. We therefore assessed administration of nasal nalbuphine as an analgesic treatment for trauma patients in Switzerland.

METHODS

This observational cohort study examined 267 patients who were treated with nasal nalbuphine by first responders in six ski resorts in Switzerland. All first responders were instructed to begin treatment by assessing the feasibility of using nalbuphine to treat pain in the patient. A treatment algorithm was developed and distributed to assure that nalbuphine was only administered following a strict protocol. Data regarding pain scores and pain reduction after administration of nalbuphine were collected on-site. Refills were handed out to the first responders with the return of each completed questionnaire.

RESULTS

Nalbuphine provided effective pain relief, with the median level of pain on the numeric rating scale for pain reduced by 3 units on average, from 8 points (p < 0.001). The multivariate regression model showed that pain reduction was more pronounced in patients with higher initial pain levels. Nalbuphine was more effective in adolsecents than in patients aged 20 to 60 years (p = 0.006). No major side effects were observed.

CONCLUSION

Nasal administration of nalbuphine by first responders is a presumably safe and effective noninvasive pain management strategy for acutely injured patients in the prehospital setting. This may be an alternative, especially in the case of severe pain and prolonged time between arrival of the first responders and arrival of EMS/HEMS personnel on scene.

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. Anaesthesia 2020;76:924-932. [PMID: 33351194 DOI: 10.1111/anae.15335]

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.

The skill of tracheal intubation with rigid scopes - a randomised controlled trial comparing learning curves in 740 intubations

Background

Rigid scopes are successfully used for management of difficult airways, but learning curves have not been established.

Methods

This randomised controlled trial was performed at the University Hospital Bern in Switzerland to establish learning curves for the rigid scopes Bonfils and SensaScope and to assess their performance. Fifteen consultant anaesthetists and 15 anaesthesia registrars performed a total of 740 intubations (10 to 20 intubations with each device per physician) in adult patients without predictors of a difficult airway under general anaesthesia. According to randomisation, physicians intubated the patient’s trachea with either the Bonfils or the SensaScope. A maximum of three intubation attempts was allowed. Primary outcome was overall time to successful intubation. Secondary outcome parameters included first attempt success, first attempt success within 60 s, failures and adverse events.

Results

A clear learning effect was demonstrated: Over 20 trials, intubations became 2.5-times quicker and first attempt intubation success probability increased by 21–28 percentage points. Fourteen and 20 trials were needed with the Bonfils and the SensaScope, respectively, to reach a 90% first attempt success probability. Intubation times were 23% longer (geometric mean ratio 1.23, 95% confidence interval 1.12–1.36, p < 0.001) and first attempt success was less likely (odds ratio 0.64, 95% confidence interval 0.45–0.92, p = 0.016) with the SensaScope. Consultants showed a tendency for a better first attempt success compared to registrars. Overall, 23 intubations (10 Bonfils, 13 SensaScope) failed. Adverse events were rare and did not differ between devices.

Conclusions

A clear learning effect was demonstrated for both rigid scopes. Fourteen intubations with the Bonfils and 20 intubations with the SensaScope were required to reach a 90% first attempt success probability. Learning of the technique seemed more complex with the SensaScope compared to the Bonfils.

Trial registration

Current Controlled Trials, ISRCTN14429285. Registered 28 September 2011, retrospectively registered.

Measurement of airway pressure during high-flow nasal therapy in apnoeic oxygenation: a randomised controlled crossover trial. Anaesthesia 2020;76:27-35. [PMID: 32776518 DOI: 10.1111/anae.15224]

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.

Mechanical chest compression devices in the helicopter emergency medical service in Switzerland

BACKGROUND

Over the past years, several emergency medical service providers have introduced mechanical chest compression devices (MCDs) in their protocols for cardiopulmonary resuscitation (CPR). Especially in helicopter emergency medical systems (HEMS), which have limitations regarding loading weight and space and typically operate in rural and remote areas, whether MCDs have benefits for patients is still unknown. The aim of this study was to evaluate the use of MCDs in a large Swiss HEMS system.

MATERIALS AND METHODS

We conducted a retrospective observational study of all HEMS missions of Swiss Air rescue Rega between January 2014 and June 2016 with the use of an MCD (Autopulse®). Details of MCD use and patient outcome are reported from the medical operation journals and the hospitals' discharge letters.

RESULTS

MCDs were used in 626 HEMS missions, and 590 patients (94%) could be included. 478 (81%) were primary missions and 112 (19%) were interhospital transfers. Forty-nine of the patients in primary missions were loaded under ongoing CPR with MCDs. Of the patients loaded after return of spontaneous circulation (ROSC), 20 (7%) experienced a second CA during the flight. In interhospital transfers, 102 (91%) only needed standby use of the MCD. Five (5%) patients were loaded into the helicopter with ongoing CPR. Five (5%) patients went into CA during flight and the MCD had to be activated. A shockable cardiac arrhythmia was the only factor significantly associated with better survival in resuscitation missions using MCD (OR 0.176, 95% confidence interval 0.084 to 0.372, p < 0.001).

CONCLUSION

We conclude that equipping HEMS with MCDs may be beneficial, with non-trauma patients potentially benefitting more than trauma patients.

Transport of COVID-19 and other highly contagious patients by helicopter and fixed-wing air ambulance: a narrative review and experience of the Swiss air rescue Rega

Background

The current COVID-19 pandemic highlights the challenges air ambulance services are facing when transporting highly infectious patients for several hours in enclosed spaces. This overview provides an example of a standard operating procedure (SOP) for infection prevention measures in HEMS missions during the COVID-19 pandemic. Furthermore, we describe different methods used by several organizations in Europe and the experience of the Swiss air rescue organization Rega in transporting these patients.

Possible benefits of the use of small patient isolation units (PIU) are discussed, including the fact that accompanying medical personnel do not need to wear personal protective equipment (PPE) during the transport but can still maintain full access to the patient. Rega has developed and patented its own PIU. This device allows spontaneously breathing or mechanically ventilated patients to be transported in pressurized jet cabins, small helicopters and ambulance vehicles, without the need to change between transport units. This PIU is unique, as it remains air-tight even when there is a sudden loss of cabin pressure.

Conclusion

A wide variety of means are being used for the aeromedical transport of infectious patients. These involve isolating either the patient or the medical crew. One benefit of PIUs is that the means of transport can be easily changed without contaminating the surroundings and while still allowing access to the patient.

Minimal Physiologically Based Pharmacokinetic Model of Intravenously and Orally Administered Delta-9-Tetrahydrocannabinol in Healthy Volunteers

BACKGROUND AND OBJECTIVES

Lack of information on the pharmacokinetics of the active moiety of Cannabis or the metabolites of delta-9-tetrahydrocannabinol (THC) does not seem to be discouraging medical or recreational use. Cytochrome P450 (CYP) 2C9, the primary enzyme responsible for THC metabolism, has two single nucleotide polymorphisms-Arg144Cys (*2) and Ile359Leu (*3). In the Caucasian population, allelic frequency is between 0.08 and 0.14 for CYP2C9*2 and between 0.04 and 0.16 for CYP2C9*3. In vitro data suggest that metabolic capacity for the variants CYP2C9*2 and CYP2C9*3 is about one-third compared to wild-type CYP2C9. Previous work has suggested exposure to the terminal metabolite is genetically determined. We therefore sought to characterize the pharmacokinetics of THC and its major metabolites 11-hydroxy-delta-9-tetrahydrocannabinol (THC-OH) and 11-nor-9-carboxy-delta-9-tetrahydrocannabinol (THC-COOH) in healthy volunteers with known CYP2C9 status by non-compartmental analysis (NCA), compartmental modeling (CM) and minimal physiologically based pharmacokinetic (mPBPK) modeling.

METHODS

Blood samples drawn for THC, THC-OH and THC-COOH after a single intravenous (IV) bolus of 0.1 mg/kg (0.32 μM/kg) THC were analyzed using a validated LC-MS/MS method. NCA generated initial estimates and CM and the mPBPK model were then fit to plasma concentration data using non-linear mixed-effects modeling. Blood samples from orally dosed (10, 25 and 50 mg) THC brownies were added to validate the model.

RESULTS

THC can be described as a high hepatic extraction ratio drug with blood flow-dependent metabolism not restricted by protein binding. THC hepatic clearance is dependent on the CYP2C9 genetic variant in the population. High extraction drugs display route-dependent metabolism. When administered via the IV or inhalation routes, induction or inhibition of CYP2C9 should be non-contributory as the elimination of THC is dependent only on liver blood flow. THC-OH is also a high extraction ratio drug, but its hepatic clearance is significantly impacted by the hepatic diffusional barrier that impedes its access to hepatic CYP2C9. THC-COOH is glucuronidated and renally cleared; subjects homozygous for CYP2C9*3 have reduced exposure to this metabolite as a result of the polymorphism reducing THC production, the hepatic diffusional barrier impeding egress from the hepatocyte, and increased renal clearance.

CONCLUSION

It has recently been reported that the terminal metabolite THC-COOH is active, implying the exposure difference in individuals homozygous for CYP2C9*3 may become therapeutically relevant. Defining the metabolism of THC in humans is important, as it is increasingly being used as a drug to treat various diseases and its recreational use is also rising. We have used NCA, CM, and mPBPK modeling of THC and its metabolites to partially disentangle the complexity of cannabis disposition in humans.

Apnoeic oxygenation with nasal cannula oxygen at different flow rates in anaesthetised patients: a study protocol for a non-inferiority randomised controlled trial

INTRODUCTION

Apnoeic oxygenation using nasal high-flow oxygen delivery systems with heated and humidified oxygen has recently gained popularity in the anaesthesia community. It has been shown to allow a prolonged apnoea time of up to 65 min as CO₂ increase was far slower compared with previously reported data from CO₂ increase during apnoea. A ventilatory exchange due to the high nasal oxygen flow was proposed explaining that phenomenon. However, recent studies in children did not show any difference in CO₂ clearance comparing high-flow with low-flow oxygen. To investigate this ventilatory exchange in adults, we plan this study comparing different oxygen flow rates and the increase of CO₂ during apnoea. We hypothesise that CO₂ clearance is non-inferior when applying low oxygen flow rates.

METHODS AND ANALYSIS

In this single-centre, single-blinded, randomised controlled trial, we randomly assign 100 patients planned for elective surgery to either control (oxygen 70 L/min, airway opened by laryngoscopy) or one of three intervention groups: oxygen 70, or 10, or 2 L/min, all with jaw thrust to secure airway patency. After anaesthesia induction and neuromuscular blockage, either one of the interventions or the control will be applied according to randomisation. Throughout the apnoea period, we will measure the increase of transcutaneous pCO₂ (tcpCO₂) until any one of the following criteria is met: time=15 min, SpO₂ <92%, tcpCO₂ >10.67 kPa, art. pH <7.1, K⁺ >6.0 mmol/L. Primary outcome is the mean tcpCO₂ increase in kPa/min.

ETHICS AND DISSEMINATION

After Cantonal Ethic Committee of Bern approval (ID 2018-00293, 22.03.2018), all study participants will provide written informed consent. Patients vulnerable towards hypoxia or hypercarbia are excluded. Study results will be published in a peer-reviewed journal and presented at national and international conferences.

TRIAL REGISTRATION NUMBER

This study was registered on www.clinicaltrials.gov (NCT03478774,Pre-results) and the Swiss Trial Registry KOFAM (SNCTP000002861).

Dislocation rates of postoperative airway exchange catheters - a prospective case series of 200 patients

Background

The dislocation rate of oral versus nasal airway exchange catheters (AEC) in the postoperative care unit (PACU) are unknown. Our aim was to establish dislocation rates and to assess the usefulness of waveform capnography to detect dislocation.

Methods

In this non-randomized, prospective observational trial at the University Hospital Bern, Switzerland, we included 200 patients admitted to PACU after extubation via AEC, having provided written informed consent. The study was approved by the local ethical committee. AEC position was assessed by nasal fiberoptic endoscopy at beginning of PACU stay and before removal of the AEC. Capnography was continuously recorded via the AEC. Additional measurements included retching and coughing of the patient, and re-intubation, if necessary.

Results

Data from 182 patients could be evaluated regarding dislocation. Overall dislocation rate was not different between oral and nasal catheters (7.2% vs. 2.7%, p = 0.16). Retching was more often noted in oral catheters (26% vs. 8%, p < 0.01). Waveform capnography was unreliable in predicting dislocation (negative predictive value 17%). Re-intubation was successful in all five of the nine re-intubations where an AEC was still in situ. In four patients, the AEC was already removed when re-intubation became necessary, and re-intubation failed once, with a front of neck access as a rescue maneuver.

Conclusions

We found no difference in dislocation rate between nasal and oral position of an airway exchange catheter. However, nasal catheters seemed to be tolerated better. In the future, catheters like the staged extubation catheter may further increase tolerance.

Trial registration

The study was registered in a clinical study registry (ISRCTN 96726807) on 10/06/2010.

Identification of the technical and medical requirements for HEMS avalanche rescue missions through a 15-year retrospective analysis in a HEMS in Switzerland: a necessary step for quality improvement

BACKGROUND

Avalanche rescues mostly rely on helicopter emergency medical services (HEMS) and include technical rescue and complex medical situations under difficult conditions. The adequacy of avalanche victim management has been shown to be unexpectedly low, suggesting the need for quality improvement. We analyse the technical rescue and medical competency requirements of HEMS crewmembers for avalanche rescue missions, as well as their clinical exposure. The study aims to identify areas that should be the focus of future quality improvement efforts.

METHODS

This 15-year retrospective study of avalanche rescue by the Swiss HEMS Rega includes all missions where at least one patient had been caught by an avalanche, found within 24 h of the alarm being raised, and transported.

RESULTS

Our analyses included 422 missions (596 patients). Crews were frequently confronted with technical rescue aspects, including winching (29%) and patient location and extrication (48%), as well as multiple casualty accidents (32%). Forty-seven percent of the patients suffered potential or overt vital threat; 29% were in cardiac arrest. The on-site medical management of the victims required a large array of basic and advanced medical skills. Clinical exposure was low, as 56% of the physicians were involved in only one avalanche rescue mission over the study period.

CONCLUSIONS

Our data provide a solid baseline measure and valuable starting point for improving our understanding of the challenges encountered during avalanche rescue missions. We further suggest QI interventions, that might be immediately useful for HEMS operating under similar settings. A coordinated approach using a consensus process to determine quality indicators and a minimal dataset for the specific setting of avalanche rescue would be the logical next step.

Early experience with high-flow nasal oxygen therapy (HFNOT) in pediatric endoscopic airway surgery

OBJECTIVE

Reporting our institutional experience with high-flow nasal oxygen therapy (HFNOT), a recently-introduced technique, for endoscopic airway approaches.

METHODS

Prospective collection of data of children (<16 years) undergoing endoscopic between January 2016 and August 2017 at a tertiary referral university hospital.

RESULTS

HFNOT was used in 6 children who underwent 14 procedures for different forms and causes of upper airway obstruction of various origins. No intraoperative complications; related to oxygenation were observed, and the surgical procedures could be carried out as; initially planned.

CONCLUSIONS

We found that HFNOT is an effective and safe technique with a variety of potential applications in the field of endoscopic pediatric airway surgery.

Is perioperative point-of-care prothrombin time testing accurate compared to the standard laboratory test?

There is no accepted way of measuring prothrombin time without time loss for patients undergoing major surgery who are at risk of intraoperative dilution and consumption coagulopathy due to bleeding and volume replacement with crystalloids or colloids. Decisions to transfuse fresh frozen plasma and procoagulatory drugs have to rely on clinical judgment in these situations. Point-of-care devices are considerably faster than the standard laboratory methods. In this study we assessed the accuracy of a Point-of-care (PoC) device measuring prothrombin time compared to the standard laboratory method. Patients undergoing major surgery and intensive care unit patients were included. PoC prothrombin time was measured by CoaguChek® XS Plus (Roche Diagnostics, Switzerland). PoC and reference tests were performed independently and interpreted under blinded conditions. Using a cut-off prothrombin time of 50%, we calculated diagnostic accuracy measures, plotted a receiver operating characteristic (ROC) curve and tested for equivalence between the two methods. PoC sensitivity and specificity were 95% (95% CI 77%, 100%) and 95% (95% CI 91%, 98%) respectively. The negative likelihood ratio was 0.05 (95% CI 0.01, 0.32). The positive likelihood ratio was 19.57 (95% CI 10.62, 36.06). The area under the ROC curve was 0.988. Equivalence between the two methods was confirmed. CoaguChek® XS Plus is a rapid and highly accurate test compared with the reference test. These findings suggest that PoC testing will be useful for monitoring intraoperative prothrombin time when coagulopathy is suspected. It could lead to a more rational use of expensive and limited blood bank resources.

Pediatric supraglottic airway devices in clinical practice: A prospective observational study

BACKGROUND

Supraglottic airway devices (SGA) are commonly used in pediatric anesthesia and serve as primary or back-up devices for difficult airway management. Most SGA are marketed without proper clinical evaluation. The purpose of this study was to evaluate the performance of the pediatric LMA Supreme™, Air-Q® and Ambu® Aura-i™.

METHODS

This prospective observational study was performed at Bern University Hospital, Switzerland. With ethics committee approval and a waiver for written informed consent 240 children undergoing elective surgery with an ASA class I-III and a weight of 5-30 kg were included. Three different pediatric supraglottic airway devices were assessed: The LMA Supreme™, Air-Q® and Ambu® Aura-i™. Primary outcome parameter was airway leak pressure. Secondary outcome parameters included first attempt and overall success rate, insertion time, fiberoptic view through the SGA, and adverse events. The primary hypothesis was that the mean airway leak pressure of each tested SGA was 20 cmH₂O ± 10%.

RESULTS

None of the SGA showed a mean airway leak pressure of 20 cmH₂O ± 10%, but mean airway leak pressures differed significantly between devices [LMA Supreme™ 18.0 (3.4) cmH₂O, Air-Q® 15.9 (3.2) cmH₂O, Ambu® Aura-i™ 17.3 (3.7) cmH₂O, p < 0.001]. First attempt success rates (LMA Supreme™ 100%, Air-Q® 90%, Ambu® Aura-i™ 91%, p = 0.02) and overall success rates (LMA Supreme™ 100%, Air-Q® 91%, Ambu® Aura-i™ 95%, p = 0.02) also differed significantly. Insertion times ranged from 20 (7) seconds (Air-Q®) to 24 (6) seconds (LMA Supreme™, <p = 0.005). Insertion was rated easiest with the LMA Supreme™ (very easy in 97% vs. Air-Q® 70%, Ambu® Aura-i™ 72%, p < 0.001). Fiberoptic view was similar between the SGA. Adverse events were rare.

CONCLUSIONS

Airway leak pressures ranged from 16 to 18 cmH₂O, enabling positive pressure ventilation with all successful SGA. The highest success rates were achieved by the LMA Supreme™, which was also rated easiest to insert.

TRIALS REGISTRATION

ClinicalTrials.gov , identifier NCT01625858 . Registered 31 May 2012.