This cross-sectional study aimed to determine whether paramedics with limited or no prior ultrasound experience can consistently identify the presence or absence of common carotid artery (CCA) pulsation, as a potential alternative to manual pulse checks during cardiopulmonary resuscitation. Following a six-minute instructional video, paramedics assessed short pre-recorded ultrasound videos of the CCA acquired in B-mode, M-mode, and Color Doppler. Each of the 93 participants viewed 24 randomized 10-second videos and classified each as showing pulsation or no pulsation. To replicate clinical conditions where manual pulse checks may fail - such as post-resuscitation - videos were recorded during two distinct phases of cardiac surgery: (1) under controlled hypotension and (2) during complete circulatory standstill following aortic clamping. A total of 2232 assessments were analyzed. M-mode: Participants correctly identified CCA pulsation in 95% (265/279) of assessments. In videos without CCA pulsation, the correct classification of 'no pulsation present' was achieved in 97% (270/279). B-mode: The presence of CCA pulsation was correctly identified in 78% (218/279), whereas in 22% (61/279) of cases, participants incorrectly categorized the video as 'no pulsation present' despite pulsation being present. Conversely, the absence of CCA pulsation was accurately detected in 98% (635/651) of cases. Color Doppler: CCA pulsation was correctly identified in 99% (551/558) of assessments. Similarly, in videos without CCA pulsation, participants correctly classified 96% (185/186) as 'no pulsation present'. Paramedics demonstrated a high level of diagnostic accuracy in identifying both the presence and absence of CCA pulsation using two-dimensional (2D) ultrasound across multiple imaging modes in a controlled study setting. The findings suggest that the combination of Color Doppler and, in particular, M-mode appears to be the most suitable approach for identifying CCA pulsation via ultrasound.

We aimed to assess the association between base excess (BE) levels and neurological outcomes in patients with out-of-hospital cardiac arrest (OHCA), accounting for the time from cardiac arrest onset to blood sampling. This multicentre study was conducted in Osaka, Japan, and enrolled consecutive patients with OHCA who were transported to 16 medical centres between 2012 and 2021. Patients aged≥18years with witnessed OHCA and available BE measurements upon hospital arrival were examined. Patients were stratified into Q1 (BE≤-21.1mmol/L), Q2 (-21.1<BE≤-15.7mmol/L), Q3 (-15.7<BE≤-10.4mmol/L) and Q4 (BE>-10.4mmol/L) groups based on BE levels. The primary outcome was 1-month survival with a favourable neurological outcome (Cerebral Performance Category scale score: 1 or 2). Among the 23,854 patients with OHCA, only 6066 were included in the final analysis. Approximately 3.2%, 4.7%, 9.9% and 23.7% of patients in the Q1, Q2, Q3 and Q4 groups, respectively, achieved favourable neurological outcomes at 1month. Compared with Q4, the adjusted odds ratio for a favourable neurological outcome in Q1 was 0.13. Subgroup analysis revealed a significant interaction between prehospital return of spontaneous circulation (ROSC) and neurological outcomes; neurological outcomes worsened as BE decreased in patients with ROSC but not in those without ROSC. Lower BE levels upon hospital arrival are associated with poorer neurological outcomes and may serve as prognostic indicators in patients with OHCA who achieved prehospital ROSC.

Ventricular fibrillation is common in patients with out-of-hospital cardiac arrest. Early and effective defibrillation is important for their survival. Effective defibrillation depends highly on correct positioning of the defibrillation pads. Teaching this correctly by ALS instructors is therefore crucial. Fifty certified advanced life support instructors were recruited from a large training institute. Participants were asked to place defibrillation pads on an anatomically and real-weight (90kg) manikin. Primary outcome was the placement of defibrillation pads placed in the sternal-apical and anterior-posterior positions. Secondary outcomes were performance self-assessment, defibrillation experience, self-perceived competence and self-efficacy in teaching defibrillation. These measures were evaluated using an 11-point Likert scale. A total of 31 medical doctors and 19 registered nurses were enrolled in this study. Defibrillation pads were placed (mean±SD) 42±21mm, 38±23mm, 35±19mm and 61±48mm from the reference point for the sternal, apical, anterior and posterior pads respectively, resulting in a respectively correct placement of 18%, 20%, 32% and 28%. The average number of correctly applied pads per instructor was 0.98±0.74 out of four.Self-assessment of defibrillation pads placed by the participants were 8.56±1.33 and 7.88±1.64 for the sternal-apical and anterior-posterior positions respectively. Personal defibrillation experience showed that the majority had applied over 20 standard defibrillations. Experience with anterior-posterior pad placement was less and experience with bi-axillary and double sequential external defibrillation positions were absent in most participants. Self-perceived competence for the sternal-apical, anterior-posterior, bi-axillary and dual external synchronized positions were 8.68±1.06, 8.08±1.37, 5.57±2.95 and 5.11±2.67 respectively. Self-efficacy score for teaching defibrillation was 8.59±0.81. No association was found between the number of correctly applied pads and any of the participants' variables. This study corroborates and expands upon existing knowledge regarding the challenges of defibrillator pad placement, revealing substantial variation in placement accuracy among instructors. Our novel analysis of pad angles and anterior-posterior analysis demonstrates that a significant portion of pads are incorrectly placed. These findings highlight the need for standardized approaches and improved training methodologies in defibrillator pad placement.