Natalie Urwyler

Crossover Comparison of the Laryngeal Mask Supreme™ and the i-gel™ in Simulated Difficult Airway Scenario in Anesthetized Patients

Background:The single-use supraglottic airway devices LMA-Supreme™ (LMA-S™; Laryngeal Mask Company, Henley-on-Thames, United Kingdom) and i-gel™ (Intersurgical Ltd, Wokingham, Berkshire, United Kingdom) have a second tube for gastric tube insertion. Only the LMA-S™ has an inflatable cuff. They have the same clinical indications and might be useful for difficult airway management. This prospective, crossover, randomized controlled trial was performed in a simulated difficult airway scenario using an extrication collar limiting mouth opening and neck movement. Methods:Sixty patients were included. Both devices were placed in random order in each patient. Primary outcome was overall success rate. Other measurements were time to successful ventilation, airway leak pressure, fiberoptic glottic view, and adverse events. Results:Success rate for the LMA-S™ was 95% versus 93% for the i-gel™ (P = 1.000). LMA-S™ needed shorter insertion time (34 ± 12 s vs. 42 ± 23 s, P = 0.024). Tidal volumes and airway leak pressure were similar (LMA-S™ 26 ± 8 cm H20; i-gel™ 27 ± 9 cm H20; P = 0.441). Fiberoptic view through the i-gel™ showed less epiglottic downfolding. Overall agreement in insertion outcome was 54 (successes) and 1 (failure) or 55 (92%) of 60 patients. The difference in success rate was 1.7% (95% CI –11.3% to 7.6%). Conclusions:Both airway devices had similar insertion success and clinical performance in the simulated difficult airway situation. The authors found less epiglottic downfolding and better fiberoptic view but longer insertion time with the i-gel™. Our study shows that both devices are feasible for emergency airway management in patients with reduced neck movement and limited mouth opening.

Performance of the Pediatric-sized i-gel Compared with the Ambu AuraOnce Laryngeal Mask in Anesthetized and Ventilated Children

Background:This prospective, randomized, controlled trial compares the performance of the pediatric i-gel (Intersurgical Ltd., Wokingham, United Kingdom) with the Ambu AuraOnce laryngeal mask (Ambu A/S, Ballerup, Denmark) in anesthetized and ventilated children. Methods:With ethics committee approval and written informed consent, the authors included 208 children, aged 0–17 yr, scheduled for elective day-surgery under general anesthesia. The primary outcome variable was oropharyngeal leak pressure. Other outcome variables were first-attempt and overall success, time to sufficient ventilation, and adverse events. Results:Demographic data did not differ between groups. The leak pressure of the i-gel was significantly higher than the leak pressure of the Ambu (mean ± SD: 22 ± 5 cm H2O vs. 19 ± 3, P < 0.01). First-attempt success was 91% for the i-gel and 93% for the Ambu (P = 0.50). Overall success was 93% for the i-gel versus 98% for the Ambu (P = 0.10). Successfully inserted i-gels needed to be secured by taping in place to ensure the seal in 44% (0% with the Ambu, P < 0.01). Insertion was faster with the Ambu (24 ± 8 s vs. 27 ± 11, P = 0.02). There were no major side effects with either device. Conclusions:The leak pressure of the i-gel was statistically but not clinically significantly higher than the leak pressure of the Ambu. Time to insertion was longer with the i-gel. Both airway devices are suitable for positive pressure ventilation with high success rates in infants and children. Because the i-gel is prone to sliding out, it must be taped in place to avoid loss of the airway.

Randomized clinical trial of the i-gel™ and Magill tracheal tube or single-use ILMA™ and ILMA™ tracheal tube for blind intubation in anaesthetized patients with a predicted difficult airway

BACKGROUND The single-use supraglottic airway device i-gel™ has been described in several case reports as a conduit for intubation, but no prospective data about success rates of blind intubation are available. Therefore, we performed this prospective randomized controlled trial to compare the success rate of blind tracheal intubation with a Magill PVC tube through the i-gel™ with intubation using an sILMA™ PVC tube through the single-use intubating laryngeal mask airway (sILMA™). METHODS With ethics committee approval and written informed consent, 80 patients with predictors of a difficult airway were computer randomized to either supraglottic airway device (SAD). The corresponding tracheal tube (TT) was introduced through the SAD under fibreoptic visualization but without fibreoptic guidance. Primary outcome was blind intubation success rate. Times, airway leak pressure, fibreoptic view, and adverse events were recorded. To control for the influence of the TT, we compared data from 40 patients described in an accompanying study (sILMA™ with Magill TT and i-gel™ with sILMA™ TT). RESULTS Blind intubation success rate through the sILMA™ (69%) was higher than with the i-gel™ (15%, P<0.001). Data from the other patient group excluded the TT type as the primary cause for the difference in success rate. Removal of SADs was without problems with no difference between the type of SAD. CONCLUSIONS Blind tracheal intubation using the sILMA™ tube through the sILMA™ is much more successful than blind intubation with a Magill PVC tube through the i-gel™. Because of its low success rate, we would not recommend blind intubation through the i-gel™.

Randomized trial comparing the i-gel™ and Magill tracheal tube with the single-use ILMA™ and ILMA™ tracheal tube for fibreoptic-guided intubation in anaesthetized patients with a predicted difficult airway

BACKGROUND The i-gel™ is a single-use supraglottic airway device (SAD) that allows fibreoptic-guided tracheal intubation through the device. Until now, no prospective data for this procedure are available. Therefore, in a prospective randomized controlled trial, we evaluated fibreoptic-guided tracheal intubation with a standard Rüsch™ PVC tracheal tube (TT) through the i-gel™ compared with the single-use ILMA™ (sILMA™) TT through the sILMA™ in patients with a predicted difficult airway. METHODS With ethics committee approval and written informed consent, 160 patients were randomly assigned to either SAD. After placement of the SAD, a fibreoptic bronchoscope was introduced into the trachea as a railroad for the TT. Primary outcome variable was the first-attempt fibreoptic-guided intubation success rate. Secondary variables included time for insertion and intubation, airway leak pressures, fibreoptic view, and adverse events. Data are presented as mean (sd) or percentages. A P-value of < 0.05 was considered statistically significant. RESULTS Fibreoptic-guided intubation was successful at the first attempt in 76 patients (96%) using the i-gel™ and in 71 patients (90%) using the sILMA™ (P=0.21). Most of the failed intubations were rescued by conventional laryngoscopy. Airway leak pressure was higher for the sILMA™. There were no problems during removal of either type of SAD. CONCLUSIONS Fibreopic-guided tracheal intubation through the i-gel™ using a standard Rüsch™ Magill TT is successful and an alternative to the sILMA™ with the sILMA™ TT.

Laboratory-based ROTEM® analysis: implementing pneumatic tube transport and real-time graphic transmission

Introduction:  ROTEM® is considered a helpful point‐of‐care device to monitor blood coagulation. Centrally performed analysis is desirable but rapid transport of blood samples and real‐time transmission of graphic results are an important prerequisite. The effect of sample transport through a pneumatic tube system on ROTEM® results is unknown. The aims of the present work were (i) to determine the influence of blood sample transport through a pneumatic tube system on ROTEM® parameters compared to manual transportation, and (ii) to verify whether graphic results can be transmitted on line via virtual network computing using local area network to the physician in charge of the patient.

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.

Accuracy of prehospital diagnosis and triage of a Swiss helicopter emergency medical service.

BACKGROUND Helicopter emergency medical services (HEMSs) have become a standard element of modern prehospital emergency medicine. This study determines the percentage of injured HEMS patients whose injuries were correctly recognized by HEMS physicians. METHODS A retrospective level III evidence prognostic study using data from the largest Swiss HEMS, REGA (Rettungsflugwacht/Guarde Aérienne), on adult patients with trauma transported to a Level I trauma center (January 2006–December 2007). National Advisory Committee on Aeronautics (NACA) scores and the Injury Severity Score (ISS) were assessed to identify severely injured patients. Injured body regions diagnosed by REGA physicians were compared with emergency department discharge diagnoses. RESULTS Four hundred thirty-three patients were analyzed. Median age was 42.1 years (interquartile range, 25.5–57.9). Three hundred twenty-three (74.6%) were men. Patients were severely injured, with an in-hospital NACA score of 4 or higher in 88.7% of patients and median ISS of 13. REGA physicians correctly recognized injuries to the head in 92.9%, to the femur in 90.5%, and to the tibia/fibula in 83.8% of patients. Injuries to these body regions were overdiagnosed in less than 30%. Abdominal injuries were missed in 56.1%, pelvic injuries in 51.8%, spinal injuries in 40.1%, and chest injuries in 31.2% of patients. CONCLUSION This study shows that patients are adequately triaged by REGA physicians reflected by a NACA score 4 or higher in 88.7% of patients and a median ISS of 13. However, recognition of injured body regions seems to be challenging in the prehospital setting. Prospective studies on specific training of HEMS physicians for recognition of these injuries (e.g., portable ultrasonography, telemedicine) might help in the future. LEVEL OF EVIDENCE Prognostic study, level III.

Trauma-induced coagulopathy in severely injured patients: knowledge lost in translation?

Background Many guidelines exist on how to treat patients with multiple injuries correctly in an accident and emergency setting. The aim of the present work was to find out how well patients are treated focusing on trauma induced coagulopathy (TIC), and what anaesthetists involved in trauma care think about their own experiences with TIC. Methods In a retrospective chart review of patients with an Injury Severity Score (ISS)≥16 between October 2007 and October 2008. A total of 172 patients with multiple injuries (134 men, 38 women) were treated in the resuscitation room and underwent complete coagulation screening (international normalised ratio (INR), activated partial thromboplastin time (aPTT), thrombin time (TT)). The presence of TIC was defined as INR>1.5 and aPTT>60 s or TT>15 s. Additionally, during the weekly anaesthesia and critical care grand round, a short questionnaire about TIC management was distributed to all anaesthetists involved in trauma care. Results Of the 172 patients with multiple injuries, 56 (32.6%) had TIC at admission to the resuscitation bay and 7 of these 56 (12.5%) received fresh-frozen plasma in the first hour of treatment. The mean of 55 anaesthetists thought that TIC could be corrected within about 30 min, although a chart review shows that it takes about 60 min to get complete laboratory based coagulation screening results. However, 70% of the doctors are not satisfied with the laboratory results they receive concerning TIC. Conclusions There is an obvious discrepancy between the content of guidelines and the everyday practice. Future academic efforts in the area of trauma care should therefore focus more on the translational approach and the implementation of existing knowledge rather than on simply formulating guidelines.

SWIVIT - Swiss video-intubation trial evaluating video-laryngoscopes in a simulated difficult airway scenario: study protocol for a multicenter prospective randomized controlled trial in Switzerland

BackgroundVideo-laryngoscopes are marketed for intubation in difficult airway management. They provide a better view of the larynx and may facilitate tracheal intubation, but there is no adequately powered study comparing different types of video-laryngoscopes in a difficult airway scenario or in a simulated difficult airway situation.Methods/DesignThe objective of this trial is to evaluate and to compare the clinical performance of three video-laryngoscopes with a guiding channel for intubation (Airtraq™, A. P. Advance™, King Vision™) and three video-laryngoscopes without an integrated tracheal tube guidance (C-MAC™, GlideScope™, McGrath™) in a simulated difficult airway situation in surgical patients. The working hypothesis is that each video-laryngoscope provides at least a 90% first intubation success rate (lower limit of the 95% confidence interval >0.9). It is a prospective, patient-blinded, multicenter, randomized controlled trial in 720 patients who are scheduled for elective surgery under general anesthesia, requiring tracheal intubation at one of the three participating hospitals. A difficult airway will be created using an extrication collar and taping the patients’ head on the operating table to substantially reduce mouth opening and to minimize neck movement. Tracheal intubation will be performed with the help of one of the six devices according to randomization. Insertion success, time necessary for intubation, Cormack-Lehane grade and percentage of glottic opening (POGO) score at laryngoscopy, optimization maneuvers required to aid tracheal intubation, adverse events and technical problems will be recorded. Primary outcome is intubation success at first attempt.DiscussionWe will simulate the difficult airway and evaluate different video-laryngoscopes in this highly realistic and clinically challenging scenario, independently from manufacturers of the devices. Because of the sufficiently powered multicenter design this study will deliver important and cutting-edge results that will help clinicians decide which device to use for intubation of the expected and unexpected difficult airway.Trial registrationNCT01692535

Evaluation of a novel needle guide for ultrasound-guided phantom vessel cannulation*

We evaluated a novel, sled‐mounted needle guide for ultrasound‐guided vessel cannulation. Fifty medical students were randomly assigned to use ultrasound with the sled (sled group, n = 23) or ultrasound without the sled (control group, n = 27) for vessel cannulation in a phantom. For each of 15 attempts we recorded cannulation time and designated a successful cannulation as 1 and a failure as 0. Our primary outcome was the mean overall success rate. The median (IQR [range]) number of successes in the sled group and control group were 15.0 (13.0–15.0 [11.0–15.0]) and 11.0 (9.0–13.0 [6.0–15.0]), respectively (p < 0.001). Cannulation time decreased from the first to the last attempt in the sled group from 7.0 s (6.0–10.0 [4.0–16]) s to 4.0 s (3.0–4.0 [1.0–6.0]) s and in the control group from 35.0 s (27.0–35.0 [11.0–35.0]) s to 7.0 s (5.0–10.0 [3.0–25.0]) s. The sled group demonstrated a shorter cannulation time at each attempt (p < 0.001). The novel sled improved the success rate and efficiency of ultrasound‐guided phantom vessel cannulation.