Wolfgang A. Wetsch

Comparison of different video laryngoscopes for emergency intubation in a standardized airway manikin with immobilized cervical spine by experienced anaesthetists. A randomized, controlled crossover trial

BACKGROUND The aim of the present study was to evaluate whether different video laryngoscopes (VLs) facilitate endotracheal intubation (ETI) faster or more secure than conventional laryngoscopy in a manikin with immobilized cervical spine. METHODS After local ethics board approval, a standard airway manikin with cervical spine immobilization by means of a standard stiff collar was placed on a trauma stretcher. We compared times until glottic view, ETI, cuff block and first ventilation were achieved, and verified the endotracheal tube position, when using Macintosh laryngoscope, Glidescope Ranger, Storz C-MAC, Ambu Pentax AWS, Airtraq, and McGrath Series5 VLs in randomized order. Wilcoxon signed-rank test and McNemars test were used for statistical analysis; p<0.05 was considered as significant. RESULTS Twenty-three anaesthetists (mean age 32.1±4.9 years, mean experience in anaesthesia of 6.9±4.8 years) routinely involved in the management of multitrauma patients participated. The primary study end point, time to first effective ventilation, was achieved fastest when using Macintosh laryngoscope (21.0±7.6s) and was significantly slower with all other devices (Airtraq 33.2±23.9 s, p=0.002; Pentax AirwayScope 32.4±14.9 s, p=0.001; Storz C-MAC 34.1±23.9 s, p<0.001; McGrath Series5 101.7±108.3 s, p<0.001; Glidescope Ranger 46.3±59.1 s, p=0.001). Overall success rates were highest when using Macintosh, Airtraq and Storz C-MAC devices (100%), and were lower in Ambu Pentax AWS and Glidescope Ranger (87%, p=0.5) and in McGrath Series5 device (72.2%, p=0.063). CONCLUSION When used by experienced anaesthesiologists, video laryngoscopes did not facilitate endotracheal intubation in this model with an immobilized cervical spine in a faster or more secure way than conventional laryngoscopy. However, data was gathered in a standardized model and further studies in real trauma patients are desirable to verify our findings.

Success rates and endotracheal tube insertion times of experienced emergency physicians using five video laryngoscopes: a randomised trial in a simulated trapped car accident victim.

Context No randomised controlled trial has yet compared different video laryngoscopes in respect of the success rates and the time taken to achieve endotracheal intubation in trapped car accident victims. Objective The aim of the present study was to evaluate whether five video laryngoscopes facilitate tracheal intubation more quickly or more securely than conventional laryngoscopy. Design Prospective, controlled, randomised crossover trial. Setting An airway manikin was placed on the drivers seat of a compact car. Access was possible only through the opened drivers door. Participants Twenty-five experienced anaesthetists. Intervention Tracheal intubation in a simulated trapped patient using video laryngoscopes in a typical out-of-hospital setting. Main outcome measures Times to achievement of a view of the glottis, tracheal intubation, cuff inflation, first ventilation and tracheal tube position were compared using a standard Macintosh laryngoscope or Glidescope Ranger, Storz C-MAC, Ambu-Pentax AWS, Airtraq and McGrath Series 5 video laryngoscopes in a randomised order. Wilcoxon signed-rank test and McNemar test were used for statistical analysis. A P value of less than 0.05 was considered statistically significant. Results Twenty-five anaesthetists (35.1 ± 7.3 years; 16 male, nine female) with an intubation experience of 374 ± 96 intubations per year and an experience of 9.1 ± 7.3 years participated. Glottic view, tracheal intubation, cuff inflation and first ventilation were achieved most rapidly with the Macintosh laryngoscope, although the Airtraq and Pentax AWS video laryngoscopes were not significantly slower. Times were significantly longer when the Glidescope Ranger, McGrath Series 5 or Storz C-MAC video laryngoscopes were used (P < 0.05), failure to place the endotracheal tube correctly was significantly commoner with the McGrath Series 5 than with the Macintosh (P = 0.031). Conclusion When attempting to intubate a trapped car accident victim, video laryngoscopes provide a better view of the glottis, but some delay tracheal intubation significantly. The devices with a tube guide (Airtraq and Ambu Pentax AWS) enable tracheal intubation to be achieved significantly faster and with a lower failure rate than devices without a tube guide. No video laryngoscope outperformed direct laryngoscopy with a Macintosh laryngoscope in this simulation study. Trial registration Clinicaltrials.gov NCT01182740.

Incidents, accidents and fatalities in 40 years of German helicopter emergency medical system operations.

Context Currently, approximately 100 000 helicopter emergency medical service (HEMS) missions for patients are undertaken in Germany each year. Compared to the early years, risk has reduced significantly, but is still higher than commercial aviation or other airborne operations. Objective The aim of the present study was to evaluate helicopter accidents and fatalities related to HEMS operations. Design Retrospective study of HEMS accidents in Germany. Setting Analysis of accidents in the published flight accident reports of the German Federal Agency for Flight Accident Investigation (40-year period from 1970 to 2009). Data were collected by telephone interview with the operators, manual search of publications and by supplemental internet information. Main outcome measures Data were analysed per 10 000 missions. For statistical analysis, Fisher[Combining Acute Accent]s exact test was used. A P value less than 0.05 was considered significant. Results During the period analysed, a total of 1.698 million HEMS missions (1970 vs. 2009: 61 vs. 98 471) were flown by a mean of 50 ± 27 (1 vs. 81) helicopters. To date, missions resulted in a total of 99 accidents with a mean of 2.4 ± 1.7 accidents per year (range 0–7). The accident rate was 0.57 (0–11.4) per 10 000 missions and the fatal accident rate was 0.11 (0–0.5). Some 64% of missions did not result in any injuries to occupants, whereas 19.2% were fatal. From the accidents analysed, 43.4% were due to collision with an obstacle during landing, take-off or hovering. Landing was the phase of flight most often associated with accidents (44.4%). Conclusion The present study is the largest on HEMS accidents and the only one analysing an entire 40-year time course beginning with inception. In comparison to previous data, a significantly lower accident rate per 10 000 missions was found. Gathering data on the early years is nearly impossible, and further analysis is required to calculate the risk of fatality or identify injury patterns.

An assessment of resuscitation quality in the television drama Emergency Room: Guideline non-compliance and low-quality cardiopulmonary resuscitation lead to a favorable outcome?

OBJECTIVE Two earlier studies found that outcome after cardiopulmonary resuscitation (CPR) in the television medical drama Emergency Room (ER) is not realistic. No study has yet evaluated CPR quality in ER. DESIGN Retrospective analysis of CPR quality in episodes of ER. SETTING Three independent board-certified emergency physicians trained in CPR and the American Heart Association (AHA) guidelines reviewed ER episodes in two 5-year time-frames (2001-2005 and 2005-2009). Congruency with the corresponding 2000 and 2005 AHA guidelines was determined for each CPR scene. PATIENTS None. INTERVENTIONS None. MAIN OUTCOME MEASURES To evaluate whether CPR is in agreement with the specific algorithms of the AHA guidelines. Fishers exact test and Mann-Whitney-U-test were used to evaluate statistical significance (P<0.05). RESULTS A total of 136 on-screen cardiac arrests occurred in 174 episodes. Trauma was the leading cause of cardiac arrest (56.6%), which was witnessed in 80.1%. Return of spontaneous circulation occurred in 38.2%. Altogether, 19.1% of patients survived until ICU admission, and 5.1% were discharged alive. CONCLUSIONS Only one CPR scene was in agreement with the published AHA guidelines. However, low-quality CPR and non-compliance with the guidelines resulted in favorable outcomes.

In a difficult access scenario, supraglottic airway devices improve success and time to ventilation.

The success of tracheal intubation (TI) is unacceptably low in unconventional positions. Supraglottic airway devices (SAD) have become an important alternative. An airway manikin was placed in a car, simulating an entrapped motor vehicle accident victim. The rescuer only had access through the driver’s door. Participants were (n=25) anaesthesiologists with experience in prehospital emergency medicine. They attempted to secure the airway by TI or an SAD (Ambu AuraOnce, iGel, laryngeal tube) in a random sequence. Performance was compared using the Wilcoxon signed-rank test. P values less than 0.05 were considered statistically significant. Fastest effective ventilation was achieved with iGel (11.5±6.9 s, P<0.001), followed by a laryngeal mask (15.1±5.6 s, P<0.001) and a laryngeal tube (17.6±5.3 s, P<0.001); TI was the slowest (42.8±23.9 s, comparator). iGel (P<0.001) and laryngeal mask (P=0.01) also significantly outperformed the laryngeal tube. First ventilation was achieved significantly faster with SADs compared with TI. Success rates were also higher when using SADs.

A suction laryngoscope facilitates intubation for physicians with occasional emergency medical service experience—A manikin study with severe simulated airway haemorrhage ☆ ☆☆

INTRODUCTION We developed a suction laryngoscope, which enables simultaneous suction and laryngoscopy in cases of airway haemorrhage and evaluated its potential benefits in physicians with varying emergency medical service experience. METHODS Eighteen physicians with regular and 24 physicians with occasional emergency medical service experience intubated the trachea of a manikin with severe simulated airway haemorrhage using the suction laryngoscope and the Macintosh laryngoscope in random order. RESULTS In physicians with regular emergency medical service experience, there was neither a difference in time needed for intubation [median (IQR, CI 95%)]: 34 (18, 30-46) vs. 34 (22, 30-52) s; P=0.52, nor in the number of oesophageal intubations [0/18 (0%) vs. 3/18 (16.7%); P=NS] when using the suction vs. the Macintosh laryngoscope. In physicians with occasional emergency medical service experience, there was no difference in time needed for intubation [median (IQR, CI 95%)]: 42 (25, 41-57) vs. 45 (33, 41-65) s; P=0.56, but the number of oesophageal intubations was significantly lower when using the suction laryngoscope [4/24 (16.7%) vs. 12/24 (50.0%); P=0.04]. CONCLUSIONS In a model of severe simulated airway haemorrhage, employing a suction laryngoscope significantly decreased the likelihood of oesophageal intubations in physicians with occasional emergency medical service experience.

Tracheal intubation in the ice-pick position with video laryngoscopes: A randomised controlled trial in a manikin

CONTEXT Tracheal intubation in nonstandardised positions is associated with a higher risk of tube misplacement and may have deleterious consequences for patients. Video laryngoscopes for tracheal intubation facilitate both glottic view and success rates. However, their use in the ice-pick position has not been evaluated. OBJECTIVE To evaluate the role of video laryngoscopes for tracheal intubation in the ice-pick position. DESIGN A randomised, controlled manikin trial. SETTING A standardised airway manikin was placed in the corner of a room. Tracheal intubation was only possible from the lower right side of the manikin. In randomised order, participants used a standard Macintosh laryngoscope and GlideScope Ranger, Storz C-MAC, Pentax AWS, Airtraq and McGrath Series5 video laryngoscopes. Statistical analysis was performed using the Wilcoxon signed-rank and McNemars tests; A P value of less than 0.05 was deemed statistically significant. PARTICIPANTS Twenty anaesthesiologists, all emergency medicine board-certified. MAIN OUTCOME MEASURES Time to first ventilation (primary); time to glottic view and confirmation of tube position (secondary). RESULTS Successful ventilation was achieved most rapidly with the Macintosh laryngoscope (36.1 ± 13.4 s; reference method), followed by the Airtraq (38.4 ± 36.3 s; P = n.s.), Pentax AWS (51.6 ± 43.3 s; P = n.s.) and Storz C-Mac (62.7 ± 49.7 s; P = n.s.). The use of the GlideScope Ranger (79.8 ± 61.9 s, P = 0.01) and McGrath series5 (79.8 ± 58.5 s, P = 0.023) resulted in significantly longer times. When comparing overall intubation success, the rate of successful tracheal intubation was higher with the Airtraq than with the McGrath Series5 (P = 0.031; all others n.s.). CONCLUSION The use of video laryngoscopes did not result in higher success rates or faster tracheal intubation in the ice-pick position when compared with conventional laryngoscopy in this manikin study. TRIAL REGISTRATION www.clinicaltrials.gov, NCT01210105.

Current national recommendations on rapid sequence induction in Europe. How standardised is the 'standard of care'?

When inducing general anaesthesia, protective reflexes of the airways diminish and finally fail – non-fasting or predisposed patients are then at risk of aspiration. Aspiration of gastric content can cause severe lung tissue damage, oxygenation disturbances and even acute respiratory distress syndrome, known after the first describer as Mendelson’s syndrome. Failure to secure the patients’ airway is a major contributor to an adverse outcome. Rapid sequence induction (RSI) is generally accepted as the technique of choice for securing the airway in patients at risk for aspiration. Such risks include conditions that predispose (e.g. gastroesophageal reflux disease), are illness-specific (e.g. ileus) or situational (e.g. non-fasting patient in an emergency). Although the concept of RSI is generally approved, the technique itself is not standardised at all. Many drugs may be used and are recommended in literature, including any combination of different hypnotics, opioids and muscle relaxants. Furthermore, several different techniques can be used, such as cricoid pressure, head-up or head-down position, extensive oxygenation prior to inductionof anaesthesia or semi-rigid stylets in the tracheal tube. In Germany, the scientific working group ‘paediatric anaesthesia’, a subgroup of specialists from the German Society of Anaesthesiology and Intensive Care (DGAI), has published a detailed recommendation on RSI for children. However, for adult patients, no recommendations have been published in our country. The aim of our study was to evaluate the situation of current recommendations for RSI in all European countries.

Dispatcher-assisted compression-only cardiopulmonary resuscitation provides best quality cardiopulmonary resuscitation by laypersons: A randomised controlled single-blinded manikin trial.

BACKGROUND High-quality cardiopulmonary resuscitation (CPR) by laypersons is a key determinant of both outcome and survival for out-of-hospital cardiac arrest. Dispatcher-assisted CPR (telephone-CPR, T-CPR) increases the frequency and correctness of bystander-CPR but results in prolonged time to first chest compressions. However, it remains unclear whether instructions for rescue ventilation and/or chest compressions should be recommended for dispatcher-assisted CPR. OBJECTIVE The aim of this study was to evaluate both principles of T-CPR with respect to CPR quality. DESIGN Randomised controlled single-blinded manikin trial. SETTING University Hospital of Cologne, Germany, 1 July 2012 to 30 September 2012. PARTICIPANTS Sixty laypersons between 18 and 65 years. Medically educated individuals, medical professionals and pregnant women were excluded. Participants were asked to resuscitate a manikin and were randomised into three groups: not dispatcher-assisted (uninstructed) CPR (group 1; U-CPR; n = 20), dispatcher-assisted compression-only CPR (group 2; DACO-CPR; n = 19) and full dispatcher-assisted CPR with rescue ventilation (group 3; DAF-CPR; n = 19). MAIN OUTCOME MEASURES Specific parameters of CPR quality [i.e. no-flow-time (NFT) as well as compression and ventilation parameters] were analysed. To compare different groups we used Students t test and P less than 0.05 was considered significant. RESULTS Initial NFT was lowest in the DACO-CPR group (mean 21.3 ± 14.4%), followed by dispatcher-assisted full CPR (mean 49.1 ± 8.5%) and by unassisted CPR (mean 55.0 ± 12.9%). Initial NFT covering the time of instruction was lower in DACO-CPR (12.1 ± 5.4%) as compared to dispatcher-assisted full CPR (20.7 ± 8.1%). Compression depth was similar in all three groups: 40.6 ± 13.0 mm (unassisted CPR), 41.0 ± 12.2 mm (DACO-CPR) and 38.8 ± 15.8 mm (dispatcher-assisted full CPR). Average compression frequency was highest in the DACO-CPR group (65.2 ± 22.4 min−1) compared with the unassisted CPR group (35.6 ± 24.2 min−1) and the dispatcher-assisted full CPR group (44.5 ± 10.8 min−1). Correct rescue ventilation was given in 3.1 ± 11.1% (unassisted CPR) and 1.6 ± 16.1% (dispatcher-assisted full CPR) of all ventilation attempts. CONCLUSION Best quality of CPR was achieved by DACO-CPR because of superior compression frequencies and reduced NFT. In contrast, the full dispatcher-assisted CPR with a longer initial instructing phase (initial NFT) did not result in enhanced CPR quality or an optimised compression depth.

Helicopter type and accident severity in helicopter emergency medical services missions

OBJECTIVE Whereas accident rates and fatal accident rates for Helicopter Emergency Medical Services (HEMS) were investigated sufficiently, resulting consequences for the occupants remain largely unknown. The present study aimed to classify HEMS accidents in Germany to prognosticate accident severity with regard to the helicopter model used. METHODS German HEMS accidents (1 Sept. 1970-31 Dec. 2009) were gathered as previously reported. Accidents were categorized in relation to the most severe injury, i.e., (1) no; (2) slight; (3) severe; and (4) fatal injuries. Only helicopter models with at least five accidents were analyzed to retrieve representative data. Prognostication was estimated by the relative percentage of each injury type compared to the total number of accidents. RESULTS The model BO105 was most often involved in accidents (38 of 99), followed by BK117 and UH-1D. OfN = 99 accidents analyzed, N = 63 were without any injuries (63.6%), N = 8 resulted in minor injuries of the occupants (8.1%), and N = 9 in major injuries (9.1%). Additionally, N = 19 fatal accidents (19.2%) were registered. EC135 and BK1 17 had the highest incidence of uninjured occupants (100% vs. 88.2%) and the lowest percentage of fatal injuries (0% vs. 5.9%; all P > 0.05). Most fatal accidents occurred with the models UH-1D, Bell 212, and Bell 412. DISCUSSION Use of the helicopter models EC135 and BK117 resulted in a high percentage of uninjured occupants. In contrast, the fatality rate was highest for the models Bell UH-I D, Bell 222, and Bell 412. Data from the present study allow for estimating accident risk in HEMS missions and prognosticating resulting fatalities, respectively.