Association Between Neuromuscular Blocking Agents and Outcomes of Emergency Tracheal Intubation: A Secondary Analysis of Randomized Trials.

STUDY OBJECTIVE: To examine the association between the neuromuscular blocking agent received (succinylcholine versus rocuronium) and the incidences of successful intubation on the first attempt and severe complications during tracheal intubation of critically ill adults in an emergency department (ED) or ICU. METHODS: We performed a secondary analysis of data from 2 multicenter randomized trials in critically ill adults undergoing tracheal intubation in an ED or ICU. Using a generalized linear mixed-effects model with prespecified baseline covariates, we examined the association between the neuromuscular blocking agent received (succinylcholine versus rocuronium) and the incidences of successful intubation on the first attempt (primary outcome) and severe complications during tracheal intubation (secondary outcome). RESULTS: Among the 2,440 patients in the trial data sets, 2,339 (95.9%) were included in the current analysis; 475 patients (20.3%) received succinylcholine and 1,864 patients (79.7%) received rocuronium. Successful intubation on the first attempt occurred in 375 patients (78.9%) who received succinylcholine and 1,510 patients (81.0%) who received rocuronium (an adjusted odds ratio of 0.87; 95% CI 0.65 to 1.15). Severe complications occurred in 67 patients (14.1%) who received succinylcholine and 456 patients (24.5%) who received rocuronium (adjusted odds ratio, 0.88; 95% CI 0.62 to 1.26). CONCLUSION: Among critically ill adults undergoing tracheal intubation, the incidences of successful intubation on the first attempt and severe complications were not significantly different between patients who received succinylcholine and patients who received rocuronium.

Association of Geographic Distance and Hospital Characteristics With Use of Interhospital Transfer by Air: A Multicenter Retrospective Study.

OBJECTIVE: Interhospital transfer by air (IHTA) represents the majority of helicopter air ambulance transports in the United States, but the evaluation of what factors are associated with utilization has been limited. We aimed to assess the association of geographic distance and hospital characteristics (including patient volume) with the use of IHTA. METHODS: This was a multicenter, retrospective study of helicopter flight request data from 2018 provided by a convenience sample of 4 critical care transport medicine programs in 3 US census regions. Nonfederal referring hospitals located in the home state of the associated critical care transport medicine program and within 100 miles of the primary receiving facility in the region were included if complete data were available. We fit a Poisson principal component regression model incorporating geographic distance, the number of emergency department visits, the number of hospital discharges, case mix index, the number of intensive care unit beds, and the number of general beds and tested the association of the variables with helicopter emergency medical services utilization. RESULTS: A total of 106 referring hospitals were analyzed, 21 of which were hospitals identified as having a consistent request pattern. Using the hospitals with a consistent referral pattern, geographic distance had a significant positive association with flight request volume. Other variables, including emergency department visit volume, were not associated. Overall, the included variables offered poor explanatory power for the observed variation between referring facilities in the use of IHTA (r2 = 0.09). Predicted flights based on the principal component regression model for all referring hospitals suggested the majority of referring hospitals used multiple flight programs. CONCLUSION: Geographic distance is associated with the use of IHTA. Unexpectedly, most basic hospital characteristics are not associated with the use of IHTA, and the degree of variation between referring facilities that is explained by patient volume is limited. The evaluation of nonhospital factors, such as the density and availability of critical care or advanced life support ground emergency medical services resources, is needed.

Association of small adult ventilation bags with return of spontaneous circulation in out of hospital cardiac arrest.

INTRODUCTION: Little is known about the impact of tidal volumes delivered by emergency medical services (EMS) to adult patients with out-of-hospital cardiac arrest (OHCA). A large urban EMS system changed from standard adult ventilation bags to small adult bags. We hypothesized that the incidence of return of spontaneous circulation (ROSC) at the end of EMS care would increase after this change. METHODS: We performed a retrospective analysis evaluating adults treated with advanced airway placement for nontraumatic OHCA between January 1, 2015 and December 31, 2021. We compared rates of ROSC, ventilation rate, and mean end tidal carbon dioxide (ETCO2) by minute before and after the smaller ventilation bag implementation using linear and logistic regression. RESULTS: Of the 1,994 patients included, 1,331 (67%) were treated with a small adult bag. ROSC at the end of EMS care was lower in the small bag cohort than the large bag cohort, 33% vs 40% (p = 0.003). After adjustment, small bag use was associated with lower odds of ROSC at the end of EMS care [OR 0.74, 95% CI 0.61 - 0.91]. Ventilation rates did not differ between cohorts. ETCO2 values were lower in the large bag cohort (33.2 ± 17.2 mmHg vs. 36.9 ± 19.2 mmHg, p < 0.01). CONCLUSION: Use of a small adult bag during OHCA was associated with lower odds of ROSC at the end of EMS care. The effects on acid base status, hemodynamics, and delivered minute ventilation remain unclear and warrant additional study.

THE COMPENSATORY RESERVE INDEX FOR PREDICTING HEMORRHAGIC SHOCK IN PREHOSPITAL TRAUMA.

ABSTRACT: Background: The compensatory reserve index (CRI) is a noninvasive, continuous measure designed to detect intravascular volume loss. CRI is derived from the pulse oximetry waveform and reflects the proportion of physiologic reserve remaining before clinical hemodynamic decompensation. Methods: In this prospective, observational, prehospital cohort study, we measured CRI in injured patients transported by emergency medical services (EMS) to a single Level I trauma center. We determined whether the rolling average of CRI values over 60 s (CRI trend [CRI-T]) predicts in-hospital diagnosis of hemorrhagic shock, defined as blood product administration in the prehospital setting or within 4 h of hospital arrival. We hypothesized that lower CRI-T values would be associated with an increased likelihood of hemorrhagic shock and better predict hemorrhagic shock than prehospital vital signs. Results: Prehospital CRI was collected on 696 adult trauma patients, 21% of whom met our definition of hemorrhagic shock. The minimum CRI-T was 0.14 (interquartile range [IQR], 0.08-0.31) in those with hemorrhagic shock and 0.31 (IQR 0.15-0.50) in those without ( P = <0.0001). The positive likelihood ratio of a CRI-T value <0.2 predicting hemorrhagic shock was 1.85 (95% confidence interval [CI], 1.55-2.22). The area under the ROC curve (AUC) for the minimum CRI-T predicting hemorrhagic shock was 0.65 (95% CI, 0.60-0.70), which outperformed initial prehospital HR (0.56; 95% CI, 0.50-0.62) but underperformed EMS systolic blood pressure and shock index (0.74; 95% CI, 0.70-0.79 and 0.72; 95% CI, 0.67-0.77, respectively). Conclusions: Low prehospital CRI-T predicts blood product transfusion by EMS or within 4 hours of hospital arrival but is less prognostic than EMS blood pressure or shock index. The evaluated version of CRI may be useful in an austere setting at identifying injured patients that require the most significant medical resources. CRI may be improved with noise filtering to attenuate the effects of vibration and patient movement.

Video versus Direct Laryngoscopy for Tracheal Intubation of Critically Ill Adults.

BACKGROUND: Whether video laryngoscopy as compared with direct laryngoscopy increases the likelihood of successful tracheal intubation on the first attempt among critically ill adults is uncertain. METHODS: In a multicenter, randomized trial conducted at 17 emergency departments and intensive care units (ICUs), we randomly assigned critically ill adults undergoing tracheal intubation to the video-laryngoscope group or the direct-laryngoscope group. The primary outcome was successful intubation on the first attempt. The secondary outcome was the occurrence of severe complications during intubation; severe complications were defined as severe hypoxemia, severe hypotension, new or increased vasopressor use, cardiac arrest, or death. RESULTS: The trial was stopped for efficacy at the time of the single preplanned interim analysis. Among 1417 patients who were included in the final analysis (91.5% of whom underwent intubation that was performed by an emergency medicine resident or a critical care fellow), successful intubation on the first attempt occurred in 600 of the 705 patients (85.1%) in the video-laryngoscope group and in 504 of the 712 patients (70.8%) in the direct-laryngoscope group (absolute risk difference, 14.3 percentage points; 95% confidence interval [CI], 9.9 to 18.7; P<0.001). A total of 151 patients (21.4%) in the video-laryngoscope group and 149 patients (20.9%) in the direct-laryngoscope group had a severe complication during intubation (absolute risk difference, 0.5 percentage points; 95% CI, -3.9 to 4.9). Safety outcomes, including esophageal intubation, injury to the teeth, and aspiration, were similar in the two groups. CONCLUSIONS: Among critically ill adults undergoing tracheal intubation in an emergency department or ICU, the use of a video laryngoscope resulted in a higher incidence of successful intubation on the first attempt than the use of a direct laryngoscope. (Funded by the U.S. Department of Defense; DEVICE ClinicalTrials.gov number, NCT05239195.).

The association between arterial-end-tidal carbon dioxide difference and outcomes after out-of-hospital cardiac arrest.

AIM: We sought to determine if the difference between PaCO2 and ETCO2 is associated with hospital mortality and neurologic outcome following out-of-hospital cardiac arrest (OHCA). METHODS: This was a retrospective cohort study of adult patients who achieved return of spontaneous circulation (ROSC) after OHCA over 3 years. The primary exposure was the PaCO2-ETCO2 difference on hospital arrival. The primary outcome was survival to hospital discharge. The secondary outcome was favorable neurologic status at discharge. We used receiver operating characteristic (ROC) curves to determine discrimination threshold and multivariate logistic regression to examine the association between the PaCO2-ETCO2 difference and outcome. RESULTS: Of 698 OHCA patients transported to the hospitals, 381 had sustained ROSC and qualifying ETCO2 and PaCO2 values. Of these, 160 (42%) survived to hospital discharge. Mean ETCO2 was 39 mmHg among survivors and 43 mmHg among non-survivors. Mean PaCO2-ETCO2 was 6.8 mmHg and 9.0 mmHg (p < 0.05) for survivors and non-survivors. After adjustment for Utstein characteristics, a higher PaCO2-ETCO2 difference on hospital arrival was not associated with hospital mortality (OR 0.99, 95% CI: 0.97-1.0) or neurological outcome. Area under the ROC curve or PaCO2-ETCO2 difference was 0.56 (95% CI 0.51-0.62) compared with 0.58 (95% CI 0.52-0.64) for ETCO2. CONCLUSION: Neither PaCO2-ETCO2 nor ETCO2 were strong predictors of survival or neurologic status at hospital discharge. While they may be useful to guide ventilation and resuscitation, these measures should not be used for prognostication after OHCA.

Increase in end-tidal carbon dioxide after defibrillation predicts sustained return of spontaneous circulation during out-of-hospital cardiac arrest.

INTRODUCTION: Guidelines recommend monitoring end-tidal carbon dioxide (ETCO2) during out-of-hospital cardiac arrest (OHCA), though its prognostic value is poorly understood. This study investigated the relationship between ETCO2 and return of spontaneous circulation (ROSC) after defibrillation in intubated non-traumatic OHCA patients. METHODS: This retrospective, observational cohort analysis included adult OHCA patients who received a defibrillation shock during treatment by an urban EMS agency from 2015 to 2021. Peak ETCO2 values were determined for the 90-second periods before and after the first defibrillation in an intubated patient (shock of interest [SOI]). Values were analyzed for association between the change in ETCO2 from pre- to post-shock and the presence of ROSC on the subsequent pulse check. RESULTS: Of 518 eligible patients, mean age was 61, 72% were male, 50% had a bystander-witnessed arrest, and 62% had at least one episode of ROSC. The most common arrest etiology was medical (92%). Among all patients, peak ETCO2 during resuscitation prior to SOI was 36.8 mmHg (18.6). ETCO2 increased in patients who achieved ROSC immediately after SOI (from 38.3 to 47.6 mmHg; +9.3 CI: 6.5, 12.1); patients with sustained ROSC experienced the greatest increase in ETCO2 after SOI (from 37.8 to 48.2 mmHg; +10.4 CI: 7.2, 13.6), while ETCO2 in patients who did not achieve ROSC after SOI rose (from 36.4 to 37.8 mmHg; +1.4 CI: -0.1, 2.8). CONCLUSIONS: ETCO2 rises after defibrillation in most patients during cardiac arrest. Patients with sustained ROSC experience larger rises, though the majority experience rises of less than 10 mmHg.

Investigating the Airway Opening Index during cardiopulmonary resuscitation.

INTRODUCTION: Chest compressions during CPR induce oscillations in capnography (ETCO2) waveforms. Studies suggest ETCO2 oscillation characteristics are associated with intrathoracic airflow dependent on airway patency. Oscillations can be quantified by the Airway Opening Index (AOI). We sought to evaluate multiple methods of computing AOI and their association with return of spontaneous circulation (ROSC). METHODS: We conducted a retrospective study of 307 out-of-hospital cardiac arrest (OHCA) cases in Seattle, WA during 2019. ETCO2 and chest impedance waveforms were annotated for the presence of intubation and CPR. We developed four methods for computing AOI based on peak ETCO2 and the oscillations in ETCO2 during chest compressions (ΔETCO2). We examined the feasibility of automating ΔETCO2 and AOI calculation and evaluated differences in AOI across the methods using nonparametric testing (α = 0.05). RESULTS: Median [interquartile range] AOI across all cases using Methods 1-4 was 28.0 % [17.9-45.5 %], 20.6 % [13.0-36.6 %], 18.3 % [11.4-30.4 %], and 22.4 % [12.8-38.5 %], respectively (p < 0.001). Cases with ROSC had a higher median AOI than those without ROSC across all methods, though not statistically significant. Cases with ROSC had a significantly higher median [interquartile range] ΔETCO2 of 7.3 mmHg [4.5-13.6 mmHg] compared to those without ROSC (4.8 mmHg [2.6-9.1 mmHg], p < 0.001). CONCLUSION: We calculated AOI using four proposed methods resulting in significantly different AOI. Additionally, AOI and ΔETCO2 were larger in cases achieving ROSC. Further investigation is required to characterize AOI's ability to predict OHCA outcomes, and whether this information can improve resuscitation care.

Effect of Use of a Bougie vs Endotracheal Tube With Stylet on Successful Intubation on the First Attempt Among Critically Ill Patients Undergoing Tracheal Intubation: A Randomized Clinical Trial.

Importance: For critically ill adults undergoing emergency tracheal intubation, failure to intubate the trachea on the first attempt occurs in up to 20% of cases and is associated with severe hypoxemia and cardiac arrest. Whether using a tracheal tube introducer ("bougie") increases the likelihood of successful intubation compared with using an endotracheal tube with stylet remains uncertain. Objective: To determine the effect of use of a bougie vs an endotracheal tube with stylet on successful intubation on the first attempt. Design, Setting, and Participants: The Bougie or Stylet in Patients Undergoing Intubation Emergently (BOUGIE) trial was a multicenter, randomized clinical trial among 1102 critically ill adults undergoing tracheal intubation in 7 emergency departments and 8 intensive care units in the US between April 29, 2019, and February 14, 2021; the date of final follow-up was March 14, 2021. Interventions: Patients were randomly assigned to use of a bougie (n = 556) or use of an endotracheal tube with stylet (n = 546). Main Outcomes and Measures: The primary outcome was successful intubation on the first attempt. The secondary outcome was the incidence of severe hypoxemia, defined as a peripheral oxygen saturation less than 80%. Results: Among 1106 patients randomized, 1102 (99.6%) completed the trial and were included in the primary analysis (median age, 58 years; 41.0% women). Successful intubation on the first attempt occurred in 447 patients (80.4%) in the bougie group and 453 patients (83.0%) in the stylet group (absolute risk difference, -2.6 percentage points [95% CI, -7.3 to 2.2]; P = .27). A total of 58 patients (11.0%) in the bougie group experienced severe hypoxemia, compared with 46 patients (8.8%) in the stylet group (absolute risk difference, 2.2 percentage points [95% CI, -1.6 to 6.0]). Esophageal intubation occurred in 4 patients (0.7%) in the bougie group and 5 patients (0.9%) in the stylet group, pneumothorax was present after intubation in 14 patients (2.5%) in the bougie group and 15 patients (2.7%) in the stylet group, and injury to oral, glottic, or thoracic structures occurred in 0 patients in the bougie group and 3 patients (0.5%) in the stylet group. Conclusions and Relevance: Among critically ill adults undergoing tracheal intubation, use of a bougie did not significantly increase the incidence of successful intubation on the first attempt compared with use of an endotracheal tube with stylet. Trial Registration: ClinicalTrials.gov Identifier: NCT03928925

Met is required for oligodendrocyte progenitor cell migration in Danio rerio.

During vertebrate central nervous system development, most oligodendrocyte progenitor cells (OPCs) are specified in the ventral spinal cord and must migrate throughout the neural tube until they become evenly distributed, occupying non-overlapping domains. While this process of developmental OPC migration is well characterized, the nature of the molecular mediators that govern it remain largely unknown. Here, using zebrafish as a model, we demonstrate that Met signaling is required for initial developmental migration of OPCs, and, using cell-specific knock-down of Met signaling, show that Met acts cell-autonomously in OPCs. Taken together, these findings demonstrate in vivo, the role of Met signaling in OPC migration and provide new insight into how OPC migration is regulated during development.

Hemostatic Resuscitation of Pediatric Trauma Patients During Air Medical Transport: A Retrospective Matched Cohort Study.

OBJECTIVE: The objective of this study was to examine an academic air ambulance service's experience with prehospital transfusion of plasma and red blood cells in pediatric trauma for evidence of efficacy on the treatment of shock and coagulopathy. METHODS: All trauma patients < 18 years old transfused during transport by the University of Washington Airlift Northwest (Airlift) air medical transport service to Harborview Medical Center, Seattle, WA, were identified. Controls were matched 1:1 from pediatric trauma patients transported by Airlift before transfusion support became available. Demographics, injury scores, emergency department admission and interval laboratory values, blood product use, and hospital outcome measures were registered. RESULTS: Seventeen cases met the inclusion criteria and were matched by age and Injury Severity Score to 17 control patients (mean age = 10.5 vs. 10.9 years; New Injury Severity Score, 37 vs. 40.7). No significant differences in vital signs, shock index, or mortality were observed. Cases received less in-flight crystalloid (4.3 mL/kg vs. 16.9 mL/kg, P = .004), had higher admission fibrinogen levels (238 vs. 148mg/dL, P = .007), and shorter time to normalization of the international normalized ratio (6.4 vs. 19.1 hours, P = .04). CONCLUSIONS: In this small series, hemostatic resuscitation during air medical transport was associated with less crystalloid administration and better support of coagulation indices.

Fewer tracheal intubation attempts are associated with improved neurologically intact survival following out-of-hospital cardiac arrest.

BACKGROUND: International guidelines emphasize advanced airway management during out-of-hospital cardiac arrest (OHCA). We hypothesized that increasing endotracheal intubation attempts during OHCA were associated with a lower likelihood of favorable neurologic survival at discharge. METHODS: This retrospective, observational cohort evaluated the relationship between number of intubation attempts and favorable neurologic survival among non-traumatic OHCA patients receiving cardiopulmonary resuscitation (CPR) from January 1, 2015-June 30, 2019 in a large urban emergency medical services (EMS) system. Favorable neurologic status at hospital discharge was defined as a Cerebral Performance Category score of 1 or 2. Multivariable logistic regression, adjusted for age, sex, witness status, bystander CPR, initial rhythm, and time of EMS arrival, was performed using the number of attempts as a continuous variable. RESULTS: Over 54 months, 1205 patients were included. Intubation attempts per case were 1 = 757(63%), 2 = 279(23%), 3 = 116(10%), ≥4 = 49(4%), and missing/unknown in 4(<1%). The mean (SD) time interval from paramedic arrival to intubation increased with the number of attempts: 1 = 4.9(2.4) min, 2 = 8.0(2.9) min, 3 = 10.9(3.3) min, and ≥4 = 15.5(4.4) min. Final advanced airway techniques employed were endotracheal intubation (97%), supraglottic devices (3%), and cricothyrotomy (<1%). Favorable neurologic outcome declined with each additional attempt: 11% with 1 attempt, 4% with 2 attempts, 3% with 3 attempts, and 2% with 4 or more attempts (AOR = 0.41, 95% CI 0.25-0.68). CONCLUSIONS: Increasing number of intubation attempts during OHCA resuscitation was associated with lower likelihood of favorable neurologic outcome.

Glutamate Signaling via the AMPAR Subunit GluR4 Regulates Oligodendrocyte Progenitor Cell Migration in the Developing Spinal Cord.

Oligodendrocyte progenitor cells (OPCs) are specified from discrete precursor populations during gliogenesis and migrate extensively from their origins, ultimately distributing throughout the brain and spinal cord during early development. Subsequently, a subset of OPCs differentiates into mature oligodendrocytes, which myelinate axons. This process is necessary for efficient neuronal signaling and organism survival. Previous studies have identified several factors that influence OPC development, including excitatory glutamatergic synapses that form between neurons and OPCs during myelination. However, little is known about how glutamate signaling affects OPC migration before myelination. In this study, we use in vivo, time-lapse imaging in zebrafish in conjunction with genetic and pharmacological perturbation to investigate OPC migration and myelination when the GluR4A ionotropic glutamate receptor subunit is disrupted. In our studies, we observed that gria4a mutant embryos and larvae displayed abnormal OPC migration and altered dorsoventral distribution in the spinal cord. Genetic mosaic analysis confirmed that these effects were cell-autonomous, and we identified that voltage-gated calcium channels were downstream of glutamate receptor signaling in OPCs and could rescue the migration and myelination defects we observed when glutamate signaling was perturbed. These results offer new insights into the complex system of neuron-OPC interactions and reveal a cell-autonomous role for glutamatergic signaling in OPCs during neural development.SIGNIFICANCE STATEMENT The migration of oligodendrocyte progenitor cells (OPCs) is an essential process during development that leads to uniform oligodendrocyte distribution and sufficient myelination for central nervous system function. Here, we demonstrate that the AMPA receptor (AMPAR) subunit GluR4A is an important driver of OPC migration and myelination in vivo and that activated voltage-gated calcium channels are downstream of glutamate receptor signaling in mediating this migration.

Cardiac Arrest in Flight: A Retrospective Chart Review of 92 Patients Transported by a Critical Care Air Medical Service.

OBJECTIVE: The purpose of this study was to describe the incidence, characteristics, and outcomes of cardiac arrest in the air medical environment so that we can begin to understand predictors of in-flight cardiac arrest and identify opportunities to improve care. METHODS: This retrospective observational study was undertaken at Airlift Northwest from 2013 to 2017. Descriptive statistics of adult patients with medical and traumatic etiologies of cardiac arrest were analyzed and compared. RESULTS: Of the 13,915 adult patients transported during the study period, fewer than 1% (N = 92) had a cardiac arrest during transport. Of those, 42% in the overall cohort had return of spontaneous circulation on arrival at the destination hospital. Medical etiologies of cardiac arrest were more common than traumatic (65% vs. 35%), more likely to have an initial shockable rhythm (30% vs. 3%, P = .004), and more frequently arrived at the receiving hospital with return of spontaneous circulation (57% vs. 31%, P = .03). Rearrest in transport occurred frequently (39%). Most patients were hypotensive before cardiac arrest, and peri-intubation cardiac arrest occurred in 12% of patients. CONCLUSION: Cardiac arrest during air medical transport is a rare event that requires a high level of critical care to treat refractory cardiac arrests, hemodynamic instability, and airway compromise.

Routine Use of a Bougie Improves First-Attempt Intubation Success in the Out-of-Hospital Setting.

STUDY OBJECTIVE: The bougie is typically treated as a rescue device for difficult airways. We evaluate whether first-attempt success rate during paramedic intubation in the out-of-hospital setting changed with routine use of a bougie. METHODS: A prospective, observational, pre-post study design was used to compare first-attempt success rate during out-of-hospital intubation with direct laryngoscopy for patients intubated 18 months before and 18 months after a protocol change that directed the use of the bougie on the first intubation attempt. We included all patients with a paramedic-performed intubation attempt. Logistic regression was used to examine the association between routine bougie use and first-attempt success rate. RESULTS: Paramedics attempted intubation in 823 patients during the control period and 771 during the bougie period. The first-attempt success rate increased from 70% to 77% (difference 7.0% [95% confidence interval 3% to 11%]). Higher first-attempt success rate was observed during the bougie period across Cormack-Lehane grades, with rates of 91%, 60%, 27%, and 6% for Cormack-Lehane grade 1, 2, 3, and 4 views, respectively, during the control period and 96%, 85%, 50%, and 14%, respectively, during the bougie period. Intubation during the bougie period was independently associated with higher first-attempt success rate (adjusted odds ratio 2.82 [95% confidence interval 1.96 to 4.01]). CONCLUSION: Routine out-of-hospital use of the bougie during direct laryngoscopy was associated with increased first-attempt intubation success rate.

Suspected Succinylcholine-Induced Masseter Muscle Rigidity During Rapid Sequence Intubation in the Air Medical Setting.

Trismus, or masseter muscle rigidity, is a rare but previously described complication of succinylcholine-induced neuromuscular blockade. We present a case report that details unique aspects of suspected masseter muscle rigidity in the prehospital setting air medical setting after attempted rapid sequence intubation with succinylcholine. We then discuss the need for knowledge base of this life-threatening and rarely described syndrome as well as the importance of working through a differential diagnosis and specific trismus-focused airway algorithm. Trismus, or masseter muscle rigidity (MMR), is a rare but previously described complication of succinylcholine-induced neuromuscular blockade. It has been cited in anesthesia and emergency medicine literature as a potentially life-threatening complication and requires prompt intervention. This case report details a unique case of suspected MMR in the prehospital setting after attempted rapid sequence intubation (RSI) with succinylcholine performed by an experienced aeromedical flight crew.

Difficult Intubation due to Penetrating Trauma from a Crossbow Bolt.

We present the case of a patient with penetrating neck and craniofacial trauma from a self-inflicted crossbow bolt injury. This case highlights the challenges involved in prehospital airway management related to an in situ foreign object penetrating the oral cavity. We review the complications associated with such injuries and considerations for effective prehospital airway management.

Causes of Chest Compression Interruptions During Out-of-Hospital Cardiac Arrest Resuscitation.

Background Interruptions in chest compressions contribute to poor outcomes in out-of-hospital cardiac arrest. The objective of this retrospective observational cohort study was to characterize the frequency, reasons, and duration of interruptions in chest compressions and to determine if interruptions changed over time. Methods and Results All out-of-hospital cardiac arrests treated by the Seattle Fire Department (Seattle, WA, United States) from 2007 to 2016 with capture of recordings from automated external defibrillators and manual defibrillators were included. Compression interruptions >1 second were classified into categories using audio recordings. Among the 3601 eligible out-of-hospital cardiac arrests, we analyzed 74 584 minutes, identifying 30 043 pauses that accounted for 6621 minutes (8.9% of total resuscitation duration). The median total interruption duration per case decreased from 115 seconds in 2007 to 72 seconds in 2016 (P<0.0001). Median individual interruption duration decreased from 14 seconds in 2007 to 7 seconds in 2016 (P<0.0001). Among interruptions >10 seconds, median interruption duration decreased from 20 seconds in 2007 to 16 seconds in 2016 (P<0.0001). Cardiac rhythm analysis accounted for most compression interruptions. Manual ECG rhythm analysis and pulse checks accounted for 41.6% of all interruption time (median individual interruption, 8 seconds), automated external defibrillator rhythm analysis for 13.7% (median, 17 seconds), and manual rhythm analysis and shock delivery for 8.0% (median, 9 seconds). Conclusions Median duration of chest compression interruptions decreased by half from 2007 to 2016, indicating that care teams can significantly improve performance. Reducing compression interruptions is an evidence-based benchmark that provides a modifiable process quality improvement goal.