Chest Decompressions - The Driver of CPR Efficacy: Exploring the Relationship Between Compression Rate, Depth, Recoil Velocity, and End-Tidal CO2.

OBJECTIVE: Cardiopulmonary arrest survival is dependent on optimization of perfusion via high quality cardiopulmonary resuscitation (CPR), defined by a complex dynamic between rate, depth, and recoil velocity. Here we explore the interaction between these metrics and create a model that explores the impact of these variables on compression efficacy. METHODS: This study was performed in a large urban/suburban fire-based emergency medical services (EMS) system over a nine-month period from 2019 to 2020. Manual chest compression parameters [rate/depth/recoil velocity] from a cohort of out-of-hospital cardiac arrest (OOHCA) victims were abstracted from monitor defibrillators (ZOLL X-series) and end-tidal carbon dioxide (ETCO2) from sensors. The mean values of these parameters were modeled against each other using multiple regression and structural equation modeling with ETCO2 as a dependent variable. RESULTS: Data from a total of 335 patients were analyzed. Strong linear relationships were observed between compression depth/recoil velocity (r = .87, p < .001), ETCO2/depth (r = .23, p < .001) and ETCO2/recoil velocity (r = .61, p < .001). Parabolic relationships were observed between rate/depth (r = .39, p < .001), rate/recoil velocity (r = .26, p < .001), and ETCO2/rate (r = .20, p = .003). Rate, depth, and recoil velocity were modeled as independent variables and ETCO2 as a dependent variable with excellence model performance suggesting the primary driver of stroke volume to be recoil velocity rather than compression depth. CONCLUSIONS: We used manual CPR metrics from out of hospital cardiac arrests to model the relationship between CPR metrics. These results consistently support the importance of chest recoil on CPR hemodynamics, suggesting that guidelines for optimal CPR should emphasize the importance of maximum chest recoil.

Application of Point-of-care Ultrasound for Screening Climbers at High Altitude for Pulmonary B-lines.

INTRODUCTION: High-altitude pulmonary edema (HAPE) occurs as a result of rapid ascent to altitude faster than the acclimatization processes of the body. Symptoms can begin at an elevation of 2,500 meters above sea level. Our objective in this study was to determine the prevalence and trend of developing B-lines at 2,745 meters above sea level among healthy visitors over four consecutive days. METHODS: We performed a prospective case series on healthy volunteers at Mammoth Mountain, CA, USA. Subjects underwent pulmonary ultrasound for B-lines over four consecutive days. RESULTS: We enrolled 21 male and 21 female participants. There was an increase in the sum of B-lines at both lung bases from day 1 to day 3, with a subsequent decrease from day 3 to day 4(P<0.001). By the third day at altitude, B-lines were detectable at base of lungs of all participants. Similarly, B-lines increased at apex of lungs from day 1 to day 3 and decreased on day 4 (P=0.004). CONCLUSION: By the third day at 2,745 meters altitude, B-lines were detectable in the bases of both lungs of all healthy participants in our study. We assume that increasing the number of B-lines could be considered an early sign of HAPE. Point-of-care ultrasound could be used to detect and monitor B-lines at altitude to facilitate early detection of HAPE, regardless of pre-existing risk factors.

Emergency Management Strategies and Antimicrobial Considerations for Nonmammalian Marine Vertebrate Penetrating Trauma in North America, the Caribbean, and Hawaii: A Review Article.

There are numerous emergency department visits in the United States for all types of marine animal injuries each year. These injuries may result in significant morbidity or mortality if not managed appropriately. Accurate identification of the offending species, thorough wound hygiene, and judicious use of antibiotics are important for preventing infections. This review aims to describe management strategies and antimicrobial considerations for nonmammalian marine vertebrate penetrating trauma in North America, the Caribbean, and Hawaii. A literature search was performed to identify studies on this subject. This literature consisted of clinical case reports and case series. Reports extracted included those on sharks, barracuda, eels, catfish, stingrays, lionfish, stonefish, and scorpionfish. The majority of reported trauma occurred to beachgoers, fishermen, or commercial aquarium employees who routinely handle these animals. Injury patterns depended on the species but most commonly affected the lower extremities. Infections were seen from saltwater bacteria, human skin flora, or marine animal oral flora. After thorough wound irrigation and exploration, most authors recommended prophylactic antimicrobials to cover Vibrio species, in addition to other gram-negative and gram-positive species. The literature is notable for the lack of controlled studies. Some authors recommended radiographic and/or ultrasonographic imaging to identify retained foreign bodies, such as spines, sand, or teeth.