Emergency Medical Services Responder Manual Ventilation Performance.

OBJECTIVE: Manual ventilation is a basic skill that every emergency medical services (EMS) responder is expected to perform proficiently. Improper manual ventilation may result in significant morbidity; however, there is no feedback mechanism or method of control for the volume, pressure, or frequency during manual ventilation. In this study, we aimed to quantify the volume and peak pressures of manually delivered breaths using a simulated lung. METHODS: One hundred ninety-nine volunteer EMS responders from the EMS World Expo 2019 and EMS Today 2020 participated in this study. Each volunteer manually ventilated a simulated lung using a bag-valve-mask (BVM) for 18 breaths. Descriptive statistics were computed for peak pressures (Ppeak) and tidal volumes (VT)), and a multivariable linear regression was conducted to determine whether there was an independent correlation between Ppeak or VT and seven different variables. RESULTS: Both Ppeak and VT delivered by EMS responders had a high level of variability; 82.9% of clinicians delivered at least one breath exceeding the recommended safety thresholds; and 98.0% delivered at least one breath that was inadequate or excessive. Our results showed no likely clinical significant role of sex, hand size, frequency of use, or years of experience in determining Ppeak and VT. Tidal volumes were significantly higher in males (p < 0.001), those using two-hand manual ventilation (p < 0.001), shorter hand length (p = 0.013), higher confidence (p < 0.001), and more years of experience (p < 0.001). Peak pressures were significantly higher in those using two-hand manual ventilation (p < 0.001), wider hand width (p = 0.004), higher confidence (p < 0.001), less frequent use of the BVM per month (p < 0.001), more experience (p < 0.001). CONCLUSIONS: Our study demonstrated large variability of VT and Ppeak within and, to a lesser degree, between clinicians. Of the seven variables that might have affected tidal volume or peak pressures, only the use of two hands versus one hand had a potentially clinically significant effect. Our study identifies a clear need for BVM improvement to ensure every practitioner can deliver breaths at appropriate volumes and safe pressures.

Pulse oximeter plethysmograph waveform and automated oscillometric sphygmomanometer for ankle-brachial index measurement.

OBJECTIVES: There are limited non-invasive methods to assess lower extremity arterial injuries in the emergency department (ED) and pre-hospital setting. The ankle-brachial index (ABI) requires careful auscultation by Doppler, an approach made difficult in noisy environments. We sought to determine the agreement of the ABI measured using the pulse oximeter plethysmograph waveform (Pleth) with auscultation by Doppler in a controlled setting. A secondary outcome sought to examine the agreement of ABI by automated oscillometric sphygmomanometer (AOS) with Doppler. METHODS: We measured blood pressure in the right upper and lower extremities of healthy volunteers using: (1) Doppler and manual sphygmomanometer; (2) Pleth and manual sphygmomanometer; and (3) AOS. The Bland-Altman approach to assessing agreement between methods was used comparing mean differences between ABI pairs to their means for Doppler versus Pleth and Doppler versus AOS. The intraclass correlation coefficient (ICC) from mixed effects models examined intra- and inter-rater reliability. RESULTS: Among 100 participants with normal ABI the mean ABI (95%CI) were Doppler 1.11 (0.90-1.33), Pleth 1.10 (0.91-1.30), and AOS 1.10 (0.90-1.30). The ABI difference (95% CI for limits of agreement) were 0.01 (-0.20,0.18) for Doppler-Pleth and 0.02 (-0.26, 0.22) for Doppler-AOS. The ICC for the Doppler-Pleth comparison (ICC = 0.56, 95% CI 0.47-0.63) was greater than for the Doppler-AOS (ICC = 0.32, 95% CI 0.19-0.43). CONCLUSIONS: The ABI measured using the Pleth has a high level of agreement with measurement by Doppler. The AOS and Doppler have good agreement with greater measurement variability. Pleth and AOS may be reasonable alternatives to Doppler for ABI.

Assessment of Ventilation Using Adult and Pediatric Manual Resuscitators in a Simulated Adult Patient.

BACKGROUND: The bag-valve-mask (BVM) or manual resuscitator bag is used as a first-line technique to ventilate patients with respiratory failure. Volume-restricted manual resuscitator bags (eg, pediatric bags) have been suggested to minimize overventilation and associated complications. There are studies that both support and caution against the use of a pediatric resuscitator bag to ventilate an adult patient. In this study, we evaluated the ability of pre-hospital clinicians to adequately ventilate an adult manikin with both an adult- and pediatric-size manual resuscitator bag without the assistance of an advanced airway or airway adjunct device. METHODS: This study was conducted at an international conference in 2022. Conference attendees with pre-hospital health care experience were recruited to ventilate an adult manikin using a BVM for 1 min with both an adult and pediatric resuscitator bag, without the use of adjunct airway devices, while 6 ventilatory variables were collected or calculated: tidal volume (VT), breathing frequency, adequate breaths (VT > 150 mL), proportion of adequate breaths, peak inspiratory pressure (PIP), and estimated alveolar ventilation (EAV). RESULTS: A total of 208 participants completed the study. Ventilation with the adult-sized BVM delivered an average VT of 290.4 mL compared to 197.1 mL (P < .001) when using the pediatric BVM. PIP with the adult BVM was higher than with the pediatric BVM (10.6 cm H2O vs 8.6 cm H2O, P < .001). The median EAV with the adult bag (1,138.1 [interquartile range [IQR] 194.0-2,869.9] mL/min) was markedly greater than with the pediatric BVM (67.7 [IQR 0-467.3] mL/min, P < .001). CONCLUSIONS: Both pediatric- and adult-sized BVM provided lower ventilation volumes than those recommended by professional guidelines for an adult. Ventilation with the pediatric BVM was significantly worse than with the adult bag when ventilating a simulated adult subject.