Abstract 14095: Use of Femoral Arterial Doppler Velocity to Detect Perfusing Pulses During Cardiac Arrest

Introduction: Manual pulse detection is inaccurate in cardiac arrest(CA) and Doppler ultrasound may detect blood flow without an adequate perfusion blood pressure (pseudo-pulseless electrical activity). The purpose of this study is to assess whether maximum femoral arterial velocity during a pulse check is correlated with arterial line systolic blood pressure (SBP) and whether it can be used to accurately identify a SBP of ≥60mmHG. Methods: This is a prospective study of CA patients at a quaternary care Emergency Department. During a pulse check, a linear ultrasound was placed at the common femoral artery and the presence or absence of an arterial Doppler waveform, the associated maximum velocity value, and arterial line SBP were recorded simultaneously. The correlation between SBP and maximum waveform velocity was assessed. Arterial SBPs were dichotomized as <60mmHG or ≥60mmHg, as this was deemed as an adequate perfusion pressure, and a receiver operator characteristic curve analysis was performed to determine optimal cutoff value of maximum velocity associated with SBP ≥60mmHG. Sensitivity (Sn), specificity (Sp), and accuracy (Acc) of manual palpation and femoral artery pulse wave doppler for detection of SBP ≥60mmHg were calculated. Results: A total of 51 patients and 183 pulse checks were analyzed. There was a strong correlation between arterial line SBP and maximum waveform velocity (Spearman correlation coefficient: 0.92; p<0.001). The optimal cutoff value of waveform velocity associated with a SBP ≥60mmHG was 20 cm/second (Sn: 0.89; specificity: 0.94; area under the curve: 0.98) with an Acc of 0.92. To detect SBP ≥60mmHg, manual palpation had a Sn of 0.45, Sp of 0.82, and Acc of 0.67 McNemar's test showed that Sn (p<0.001), Sp (p=0.009), and Acc (p<0.001) was significantly higher for doppler ultrasound >=20cm/sec compared with manual palpation. Conclusion: In this study, during a pulse check, patients with a femoral arterial doppler waveform with a maximum velocity greater than 20cm/sec had a high probability of having a SBP ≥60mmHg, and improved Sn, Sp and Acc over manual palpation. The results demonstrate femoral arterial doppler maximum velocity is an accurate and objective tool to determine the presence of a pulse with adequate perfusion pressures.

Machine learning and feature engineering for predicting pulse presence during chest compressions

Current resuscitation protocols require pausing chest compressions during cardiopulmonary resuscitation (CPR) to check for a pulse. However, pausing CPR when a patient is pulseless can worsen patient outcomes. Our objective was to design and evaluate an ECG-based algorithm that predicts pulse presence with or without CPR. We evaluated 383 patients being treated for out-of-hospital cardiac arrest with real-time ECG, impedance and audio recordings. Paired ECG segments having an organized rhythm immediately preceding a pulse check (during CPR) and during the pulse check (without CPR) were extracted. Patients were randomly divided into 60% training and 40% test groups. From training data, we developed an algorithm to predict the clinical pulse presence based on the wavelet transform of the bandpass-filtered ECG. Principal component analysis was used to reduce dimensionality, and we then trained a linear discriminant model using three principal component modes as input features. Overall, 38% (351/912) of checks had a spontaneous pulse. AUCs for predicting pulse presence with and without CPR on test data were 0.84 (95% CI (0.80, 0.88)) and 0.89 (95% CI (0.86, 0.92)), respectively. This ECG-based algorithm demonstrates potential to improve resuscitation by predicting the presence of a spontaneous pulse without pausing CPR with moderate accuracy.

Video Case Review for Quality Improvement During Cardiac Arrest Resuscitation in the Emergency Department

Background: Cardiac arrests (CA) are a leading global cause of mortality. The American Heart Association (AHA) promotes several important strategies associated with improved cardiac arrest outcomes, including decreasing pulse check time and maintaining a chest compression fraction (CCF) > 0.80. Video review is a potential tool to improve skills and analyze deficiencies in various situations, however its use in improving medical resuscitation remains poorly studied in the emergency department (ED). We implemented a quality improvement initiative, which utilized video review of cardiac arrest resuscitations in an effort to improve compliance with such AHA quality metrics. Methods: A cardiopulmonary resuscitation Video Review Team (CoVeRT) of emergency medicine residents were assembled to analyze CA resuscitations in our urban academic ED. Videos were reviewed by two residents, one of whom was a senior resident (PGY-3 or -4), and analyzed for numerous quality improvement metrics, including pulse check time, CCF, time to intravenous access, and time to patient attached to monitor. Results: We collected data on 94 cardiac arrest resuscitations between July 2017 and June 2020. Average pulse check time was 13.09 (SD ±5.97) seconds, and 38% of pulse checks were less than 10 seconds. After the implementation of the video review process, there was a significant decrease in average pulse check time (p=0.01) and a significant increase in CCF (p=0.01) throughout the study period. Conclusions: Our study suggests that the video review and feedback process was significantly associated with improvements in AHA quality metrics for resuscitation in CA among patients presented to the ED.

Abstract 128: Time for a Change: Use of Doppler Ultrasound for Pulse Checks in Cardiac Arrest Patients

Introduction: During cardiopulmonary resuscitation, the presence or absence of a pulse is critical in guiding the management of cardiac arrest (CA) patients. Despite the importance placed on palpating a pulse, several reports have shown that providers lack accuracy in determining it the presence via manual palpation. The purpose of this study is to assess the sensitivity, specificity, and accuracy of manual femoral pulse detection as compared to Doppler ultrasound pulse detection in CA patients. Hypothesis: We hypothesize that a Doppler ultrasound obtained pulse will be more accurate than manual palpation for detecting an arterial pulse in patients in CA. Methods: This is a prospective observational study of non-traumatic CA patients that occurred at North Shore University Hospital. During a pulse check, the presence of both a femoral Doppler waveform and manual femoral pulse were recorded simultaneously. These values were compared to the arterial line waveform, which served as the gold standard. During each pulse check, the presence or absence of a pulse was documented, as well as the arterial line measurement. We calculated the sensitivity, specificity, and accuracy of manual palpation and Doppler ultrasound determination of the presence of a pulse. Results: We enrolled a total of 23 patients. The sensitivity of Doppler ultrasound detection of a pulse was 0.82 (95% CI: 0.72, 0.93) with a specificity of 1.00 (95% CI: 1.00, 1.00), and accuracy of 0.88 (95% CI: 0.78, 0.94). The sensitivity and specificity of manual palpation of a pulse was 0.27 (95% CI: 0.15, 0.40) and 0.90 (95% CI: 0.78, 1.00), respectively, with an accuracy of 0.46 (95% CI: 0.34, 0.58). Conclusion: Determining the presence of a pulse in the management of cardiac arrest patients is a critical step in the Advanced Cardiovascular Life Support algorithm. Our preliminary data suggests that Doppler ultrasound has a higher sensitivity and specificity for detecting a pulse in CA patients and highlights the inaccuracy of manual pulse palpation. These preliminary results could lead to a change in the practice of pulse checks, to favor the use of Doppler ultrasound detection. Further data is needed to determine what blood pressure readings correspond to a perfusable rhythm.