Prehospital Manual Ventilation: An NAEMSP Position Statement and Resource Document

Exploring the reliability and profile of frequent mental health presentations using different methods: An observational study using statewide ambulance data over a 4-year period

INTRODUCTION

A disproportionate number of mental health presentations to emergency services are made by frequent presenters. No current consensus definition of a frequent presenter exists. Using a statewide population-based ambulance database, this study (i) applied previous statistical methods to determine thresholds for frequent presenters, (ii) explored characteristics of the identified frequent presenter groups compared to non-frequent presenters and (iii) assessed the reliability of these methods in predicting continued frequent presenter status over time.

METHODS

Statistical methods utilised in previous studies to identify frequent presenters were applied to all ambulance attendances for mental health symptoms, self-harm and alcohol and other drug issues between 1 January 2017 and 31 December 2020 in Victoria, Australia. Differences in characteristics between identified frequent and non-frequent presenter groups were determined by logistic regression analysis. The consistency of agreement of frequent presenter status over time was assessed using intraclass correlation coefficients.

RESULTS

Thresholds for frequent presenters ranged from a mean of 5 to 39 attendances per calendar year, with groups differing in size, service use and characteristics. Compared to non-frequent presenters, frequent presenters had greater odds of being female, presenting with self-harm, experiencing social disadvantage or housing issues, involving police co-attendance and being transported to hospital. All frequent presenter definitions had poor reliability in predicting ongoing frequent presentations over time.

CONCLUSION

A range of methods can define frequent presenters according to thresholds of yearly service use. Reasons for identifying frequent presenters may influence the method chosen. Future studies should explore definitions that capture the dynamic nature of presentations by this group.

Rationale and development of a prehospital goal-directed bundle of care to prevent rearrest after return of spontaneous circulation

In patients with out-of-hospital cardiac arrest (OHCA) who attain return of spontaneous circulation (ROSC), rearrest while in the prehospital setting represents a significant barrier to survival. To date, there are limited data to guide prehospital emergency medical services (EMS) management immediately following successful resuscitation resulting in ROSC and prior to handoff in the emergency department. Post-ROSC care encompasses a multifaceted approach including hemodynamic optimization, airway management, oxygenation, and ventilation. We sought to develop an evidenced-based, goal-directed bundle of care targeting specified vital parameters in the immediate post-ROSC period, with the goal of decreasing the incidence of rearrest and improving survival outcomes. Here, we describe the rationale and development of this goal-directed bundle of care, which will be adopted by several EMS agencies within California. We convened a group of EMS experts, including EMS Medical Directors, quality improvement officers, data managers, educators, EMS clinicians, emergency medicine clinicians, and resuscitation researchers to develop a goal-directed bundle of care to be applied in the field during the period immediately following ROSC. This care bundle includes guidance for prehospital personnel on recognition of impending rearrest, hemodynamic optimization, ventilatory strategies, airway management, and diagnosis of underlying causes prior to the initiation of transport.

Effects of weights applied to the apex of a bag-valve-mask and pinch strength on tidal volume: a prospective simulation study

A bag-valve-mask (BVM) is a first aid tool that can easily and quickly provide positive-pressure ventilation in patients with breathing difficulties. The most important aspect of BVM bagging is how closely the mask adheres to the patient's face when the E-C technique is used. In particular, the greater the adhesion force at the apex of the mask, the greater the tidal volume. The purpose of this study was to investigate the effect of various weights applied to the mask's apex and the pinch strength needed to perform the E-C technique, on tidal volume. In this prospective simulation study, quasi-experimental and equivalent time-series designs were used. A total of 72 undergraduate paramedic student from three universities were recruited using convenience sampling. The tidal volumes according to the weights (0 g, 100 g, 200 g, 300 g) applied to the apical area of the mask, handgrip strength, and pinch strength (tip pinch strength, key pinch strength, and tripod pinch strength) were measured. A linear mixed model analysis was performed. Linear mixed model analyses showed that tidal volume was significantly higher at 200 g (B = 43.38, p = 0.022) and 300 g (B = 38.74, p = 0.017) than at 0 g. Tripod pinch strength (B = 12.88, p = 0.007) had a significant effect on mask adhesion for effective BVM ventilation. Adding weight to the apical area of the mask can help maintain the E-C technique and enable effective ventilation. Future studies are required to develop specific strategies to improve the ventilation skills, which can be an important first-aid activity.

Evidence-Based Guideline for Prehospital Airway Management

Airway management is a cornerstone of emergency medical care. This project aimed to create evidence-based guidelines based on the systematic review recently conducted by the Agency for Healthcare Research and Quality (AHRQ). A technical expert panel was assembled to review the evidence using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) methodology. The panel made specific recommendations on the different PICO (population, intervention, comparison, outcome) questions reviewed in the AHRQ review and created good practice statements that summarize and operationalize these recommendations. The recommendations address the use of ventilation with bag-valve mask ventilation alone vs. supraglottic airways vs. endotracheal intubation for adults and children with cardiac arrest, medical emergencies, and trauma. Additional recommendations address the use of video laryngoscopy and drug-assisted airway management. These recommendations, and the associated good practice statements, offer EMS agencies and clinicians an opportunity to review the available evidence and incorporate it into their airway management strategies.

Bag-Valve-Mask Ventilation and Survival From Out-of-Hospital Cardiac Arrest: A Multicenter Study

BACKGROUND

Few studies have measured ventilation during early cardiopulmonary resuscitation (CPR) before advanced airway placement. Resuscitation guidelines recommend pauses after every 30 chest compressions to deliver ventilations. The effectiveness of bag-valve-mask ventilation delivered during the pause in chest compressions is unknown. We sought to determine: (1) the incidence of lung inflation with bag-valve-mask ventilation during 30:2 CPR; and (2) the association of ventilation with outcomes after out-of-hospital cardiac arrest.

METHODS

We studied patients with out-of-hospital cardiac arrest from 6 sites of the Resuscitation Outcomes Consortium CCC study (Trial of Continuous Compressions versus Standard CPR in Patients with Out-of-Hospital Cardiac Arrest). We analyzed patients assigned to the 30:2 CPR arm with ≥2 minutes of thoracic bioimpedance signal recorded with a cardiac defibrillator/monitor. Detectable ventilation waveforms were defined as having a bioimpedance amplitude ≥0.5 Ω (corresponding to ≥250 mL VT) and a duration ≥1 s. We defined a chest compression pause as a 3- to 15-s break in chest compressions. We compared the incidence of ventilation and outcomes in 2 groups: patients with ventilation waveforms in <50% of pauses (group 1) versus those with waveforms in ≥50% of pauses (group 2).

RESULTS

Among 1976 patients, the mean age was 65 years; 66% were male. From the start of chest compressions until advanced airway placement, mean±SD duration of 30:2 CPR was 9.8±4.9 minutes. During this period, we identified 26 861 pauses in chest compressions; 60% of patients had ventilation waveforms in <50% of pauses (group 1, n=1177), and 40% had waveforms in ≥50% of pauses (group 2, n=799). Group 1 had a median of 12 pauses and 2 ventilations per patient versus group 2, which had 12 pauses and 12 ventilations per patient. Group 2 had higher rates of prehospital return of spontaneous circulation (40.7% versus 25.2%; P<0.0001), survival to hospital discharge (13.5% versus 4.1%; P<0.0001), and survival with favorable neurological outcome (10.6% versus 2.4%; P<0.0001). These associations persisted after adjustment for confounders.

CONCLUSIONS

In this study, lung inflation occurred infrequently with bag-valve-mask ventilation during 30:2 CPR. Lung inflation in ≥50% of pauses was associated with improved return of spontaneous circulation, survival, and survival with favorable neurological outcome.

Pre-intubation ventilation device for bearded patients: prospective, randomized, crossover trial in anesthetized patients

Having a beard is an independent predictor of difficult ventilation by face mask. This study evaluates the efficacy of a novel intra-oral Bag-Valve-Guedel Adaptor (BVGA) in anaesthetized bearded patients. Patients with ASA score 1-2, scheduled for elective surgery, were recruited for this prospective, crossover trial. Beard length was categorized as < 0.5 cm, 0.5-1 cm, 1-5 cm, or > 5 cm. Patients were ventilated by attending anesthesiologists using the BVGA and a facemask (both with a Guedel oral airway). End-tidal CO₂ (EtCO₂) and expiratory tidal volume (TV) were recorded as was the number of hands required for the procedure. The primary outcome was the difference between BVGA and Facemask. Sixty-one patients were enrolled. Of these, 38 had beards, and 23 were without beards or with beards < 0.5 cm length. In bearded patients, ventilation with the BVGA was superior to the face mask by EtCO₂ and non-inferior by TV (BVGA-vs-Mask, mean [95% CI]: EtCO₂ [mmHg], 33.0 [31.6, 34.3]-vs-27.2 [25.5, 28.8], p < 0.001; TV [ml∙kg^-1 IBW], 8.1 [7.4, 8.9]-vs-6.9 [6.0, 7.7], p = 0.11). The BVGA was found to be superior to the face mask by EtCO₂ across all beard lengths (p ≤ 0.001), but by TV only for the longest beard group (p = 0.009). After securing the BVGA, ventilation was possible without hands in 74% of the cases - clearly impossible with the facemask (p ≤ 0.001). The BVGA is more effective and more convenient than the facemask in anaesthetized bearded patients. A follow-up study is underway to test whether replacing the face mask with the BVGA will improve effectiveness and ease of pre-intubation field ventilation by less-experienced, first responders.