Period Of Cardiopulmonary Resuscitation Research Articles

Abstract 315: Endovascular Aortic Occlusion Preferentially Improves Hemodynamics and Return of Spontaneous Circulation After Longer Periods of Cardiopulmonary Resuscitation: A Translational Study in Swine

Introduction: Non-traumatic cardiac arrest (NTCA) is associated with low survival and substantial societal cost. Standard-of-care treatments, such as cardiopulmonary resuscitation (CPR) and advanced cardiac life support (ACLS), have limitations in restoring cardiac function and improving outcomes. Resuscitative endovascular balloon occlusion of the aorta (REBOA) has emerged as an adjunct to CPR for NTCA. However, the optimal patient population that will benefit most from REBOA remains uncertain. Goals: This translational study investigated the impact of varying low-flow duration (15- vs 30-mins) on REBOA's hemodynamic performance and ability to achieve return of spontaneous circulation (ROSC) in a swine model of NTCA. Methods: Thirty-two swine were anesthetized and placed into ventricular fibrillation. All animals received a 4-min “no-flow” period before mechanical CPR was initiated. Animals were randomized into four groups to receive: 1) 15- vs 30-minutes of CPR; 2) REBOA vs. no-REBOA (control). After completion of the 15- or 30-minute low-flow period, ACLS was initiated and REBOA was fully-inflated in experimental animals. Results: There were no differences in demographics or hemodynamics at baseline (T = -10-mins) or at randomization (T = +10-mins). In the 15-mins groups, there were no differences in the rates of ROSC between REBOA (4 / 8, 50%) and control (4 / 8, 50%; p = 0.99). However, in the 30-min group the REBOA animals had a significantly higher rate of ROSC (6 / 8, 75%) compared to control (1 / 8, 12.5%; p = 0.04). In the 7-mins (T = 34 - 41 mins) after REBOA deployment in the 30-min animals there was a statistically significant difference in diastolic blood pressure (repeated measures ANOVA; p = 0.027). Importantly, 5 / 6 (83%) animals that received ROSC in the 30-min group with REBOA re-arrested at least once with 3 / 6 (50%) maintaining ROSC until study completion. Conclusion: In our swine model of NTCA, REBOA preferentially improved hemodynamics and ROSC after a 30-mins period of low-flow CPR, compared to 15-mins of low-flow CPR. REBOA may be a viable strategy to improve ROSC after prolonged downtime. More hemodynamic support will be required to maintain ROSC. This has implications for patient selection in upcoming human trials of REBOA in NTCA.

Prediction of Return of Spontaneous Circulation in a Pediatric Swine Model of Cardiac Arrest Using Low-Resolution Multimodal Physiological Waveforms.

Monitoring physiological waveforms, specifically hemodynamic variables (e.g., blood pressure waveforms) and end-tidal CO2 (EtCO2), during pediatric cardiopulmonary resuscitation (CPR) has been demonstrated to improve survival rates and outcomes when compared to standard depth-guided CPR. However, waveform guidance has largely been based on thresholds for single parameters and therefore does not leverage all the information contained in multimodal data. We hypothesize that the combination of multimodal physiological features improves the prediction of the return of spontaneous circulation (ROSC), the clinical indicator of short-term CPR success. We used machine learning algorithms to evaluate features extracted from eight low-resolution (4 samples per minute) physiological waveforms to predict ROSC. The waveforms were acquired from the 2nd to 10th minute of CPR in pediatric swine models of cardiac arrest (N = 89, 8-12 kg). The waveforms were divided into segments with increasing length (both forward and backward) for feature extraction, and machine learning algorithms were trained for ROSC prediction. For the full CPR period (2nd to 10th minute), the area under the receiver operating characteristics curve (AUC) was 0.93 (95% CI: 0.87-0.99) for the multivariate model, 0.70 (0.55-0.85) for EtCO2 and 0.80 (0.67-0.93) for coronary perfusion pressure. The best prediction performances were achieved when the period from the 6th to the 10th minute was included. Poor predictions were observed for some individual waveforms, e.g., right atrial pressure. In conclusion, multimodal waveform features carry relevant information for ROSC prediction. Using multimodal waveform features in CPR guidance has the potential to improve resuscitation success and reduce mortality.

Effect of first epinephrine administration time on cerebral perfusion pressure and cortical cerebral blood flow in a porcine cardiac arrest model

ObjectiveThe optimal time for epinephrine administration and its effects on cerebral blood flow (CBF) and microcirculation remain controversial. This study aimed to assess the effect of the first administration of epinephrine on cerebral perfusion pressure (CePP) and cortical CBF in porcine cardiac arrest model. MethodsAfter 4 min of untreated ventricular fibrillation, eight of 24 swine were randomly assigned to the early, intermediate, and late groups. In each group, epinephrine was administered intravenously at 5, 10, and 15 min after cardiac arrest induction. CePP was calculated as the difference between the mean arterial pressure and intracranial pressure. Cortical CBF was measured using a laser Doppler flow probe. The outcomes were CePP and cortical CBF measured continuously during cardiopulmonary resuscitation (CPR). Mean CePP and cortical CBF were compared using analysis of variance and a linear mixed model. ResultsThe mean CePP was significantly different between the groups at 6–11 min after cardiac arrest induction. The mean CePP in the early group was significantly higher than that in the intermediate group at 8–10 min and that in the late group at 6–9 min and 10–11 min. The mean cortical CBF was significantly different between the groups at 9–11 min. The mean cortical CBF was significantly higher in the early group than in the intermediate and late group at 9–10 min. ConclusionEarly administration of epinephrine was associated with improved CePP and cortical CBF compared to intermediate or late administration during the early period of CPR.

Association between the presence of an advanced airway and ventilation rate during pediatric CPR: A report from the Videography in Pediatric Resuscitation (VIPER) collaborative

ObjectiveTo determine the association between presence of an advanced airway during pediatric cardiopulmonary resuscitation (CPR) and ventilation rates. MethodsProspective observational study, January 2017 to June 2020. Patients ≤18 years receiving CC for ≥2 minutes were enrolled. Ventilation rate and type of airway (advanced airway (AA), either endotracheal tube (ETT) or supraglottic airway (SGA); or natural airway (NA)) were collected from video review and analyzed in ‘CPR segments’ (periods of CPR by individual providers). Ventilation rate (breaths per minute, bpm) was calculated for each segment; hyperventilation was defined as >12 bpm according to 2015 American Heart Association guidelines. Univariate analysis between airway type was done by χ2 testing. Multivariate regression was used to determine the association between the presence of AA with hyperventilation while controlling for within-patient covariance. Results779 CPR segments from 94 CPR event were analyzed. The mean ventilation rate per CPR segment across all events was 22 bpm (±16 bpm)). Mean ventilation rates were higher with AA, either ETT (24 ± 17 bpm) or SGA (34 ± 19 bpm), than with NA (17 ± 14, p < 0.001). Hyperventilation occurred more often with AA in place (ETT: 68%; SGA: 96%; NA: 43%; p < 0.001). The presence of AA was independently associated with hyperventilation (AOR 9.3, 95% CI 4.3–20.1). ConclusionsDuring pediatric CPR, hyperventilation occurs more often with an AA in place than during CPR with NA. Future research should focus on respiratory physiology during pediatric CPR to determine optimal ventilation rate(s) during pediatric cardiac arrest.

Femoral Arterial Doppler Use During Active Cardiopulmonary Resuscitation.

This study explored femoral arterial Doppler during active cardiopulmonary resuscitation (CPR) to identify and characterize the resumptions of cardiac activity without stopping CPR. This was a proof-of-concept study exploring arterial Doppler during cardiac arrest. Patients in cardiac arrest undergoing active CPR were prospectively enrolled. Arterial Doppler of the common femoral artery was recorded during CPR and during pauses in CPR. CPR-induced arterial tracings and native cardiac-induced tracings were analyzed for rate and peak systolic velocity. Cardiac activity on echocardiogram during pause in CPR was classified as "absent," "disorganized," or "organized." Descriptive data and survival are presented as mean and 95% confidence intervals (CI), as well as sensitivity and specificity of Doppler during active CPR in detecting native cardiac pulsations. Sixteen patients with 48 paired Doppler recordings during active CPR, pause in CPR, and associated echocardiogram were enrolled. Native cardiac-induced tracings were visible during 39.6% of pauses in CPR (19 of 48) and during 18.8% of the periods of active CPR (9 of 48). Arterial pulsations were more frequently visualized with organized contractions by echocardiogram (10 of 14, 71%) than disorganized contractions (9 of 22, 41%). Arterial Doppler was 100% specific and 50% sensitive in detecting organized cardiac activity during active CPR. Patients with visible native cardiac pulsations during active CPR demonstrated 0% mortality compared with 67% mortality without visible arterial pulsations. Arterial Doppler tracings may identify the resumption of native cardiac activity during active CPR; however, more research is needed.

A Comparison between Three Different Techniques Considering Quality Skills, Fatigue and Hand Pain during a Prolonged Infant Resuscitation: A Cross-Over Study with Lifeguards.

The aim of the study was to compare the quality of CPR (Q-CPR), as well as the perceived fatigue and hand pain in a prolonged infant cardiopulmonary resuscitation (CPR) performed by lifeguards using three different techniques. A randomized crossover simulation study was used to compare three infant CPR techniques: the two-finger technique (TF); the two-thumb encircling technique (TTE) and the two-thumb-fist technique (TTF). 58 professional lifeguards performed three tests in pairs during a 20-min period of CPR. The rescuers performed compressions and ventilations in 15:2 cycles and changed their roles every 2 min. The variables of analysis were CPR quality components, rate of perceived exertion (RPE) and hand pain with numeric rating scale (NRS). All three techniques showed high Q-CPR results (TF: 86 ± 9%/TTE: 88 ± 9%/TTF: 86 ± 16%), and the TTE showed higher values than the TF (p = 0.03). In the RPE analysis, fatigue was not excessive with any of the three techniques (values 20 min between 3.2 for TF, 2.4 in TTE and 2.5 in TTF on a 10-point scale). TF reached a higher value in RPE than TTF in all the intervals analyzed (p < 0.05). In relation to NRS, TF showed significantly higher values than TTE and TTF (NRS minute 20 = TF 4.7 vs. TTE 2.5 & TTF 2.2; p < 0.001). In conclusion, all techniques have been shown to be effective in high-quality infant CPR in a prolonged resuscitation carried out by lifeguards. However, the two-finger technique is less efficient in relation to fatigue and hand pain compared with two-thumb technique (TF vs. TTF, p = 0.01).

Supraglottic Airway Device to Improve Ventilation Success and Reduce Pulmonary Aspiration during Cardio-Pulmonary Resuscitation by Basic Life Support Rescuers: A Randomized Cross-over Human Cadaver Study

Objectives Early airway management during cardiopulmonary resuscitation (CPR) prevents aspiration of gastric contents. Endotracheal intubation is the gold standard to protect airways, but supraglottic airway devices (SGA) may provide some protection with less training. Bag-mask ventilation (BMV) is the most common method used by rescuers. We hypothesized that SGA use by first rescuers during CPR could increase ventilation success rate and also decrease intragastric pressure and pulmonary aspiration. Methods We performed a randomized cross-over experimental trial on human cadavers. Protocol A: we assessed the rate of successful ventilation (chest rise), intragastric pressure, and CPR key time metrics. Protocol B: cadaver stomachs were randomized to be filled with 300 mL of either blue or green serum saline solution through a Foley catheter. Each rescuer was randomly assigned to use SGA or BMV during a 5-minute standard CPR period. Then, in a crossover design, the stomach was filled with the second color solution and another 5-minute CPR period was performed using the other airway method. Pulmonary aspiration, defined as the presence of colored solution below the vocal cords, was assessed by a blinded operator using bronchoscopy. A generalized linear mixed model was used for statistical analysis. Results Protocol A: Forty-eight rescuers performed CPR on 11 cadavers. Median ventilation success was higher with SGA than BMV: 75.0% (IQR: 59.8–87.3) vs. 34.7% (IQR: 25.0–50.0), (p = 0.003). Gastric pressure and differential (maximum minus minimum) gastric pressure were lower in the SGA group: 2.21 mmHg (IQR: 1.66; 2.68) vs. 3.02 mmHg (IQR: 2.02; 4.22) (p = 0.02) and 5.70 mmHg (IQR: 4.10; 7.60) vs. 8.05 mmHg (IQR: 5.40; 11.60) (p = 0.05). CPR key times were not different between groups. Protocol B: Ten cadavers were included with 20 CPR periods. Aspiration occurred in 2 (20%) SGA procedures and 5 (50%) BMV procedures (p = 0.44). Conclusion Use of SGA by rescuers improved the ventilation success rate, decreased intragastric pressure, and did not affect key CPR metrics. SGA use by basic life support rescuers appears feasible and efficient.

Determine the Arrest Factors in Survival Outcome of Patients with IHCA

Introduction: In-hospital cardiac arrest (IHCA) is a common health problem associated with high levels of mortality. Successful defibrillation is known to improve outcomes in ventricular fibrillation/ventricular tachycardia. However, it has been hypothesized that a period of cardiopulmonary resuscitation (CPR) before defibrillation, increasing the likelihood of successful defibrillation. The order of priority of CPR versus defibrillation therefore remains in contention. Objectives: (1) To determine the arrest factors in survival outcome of IHCA. (2) To associate the arrest factors in survival outcome of IHCA with their selected demographic variables. Materials and methods: A total of 125 samples were selected and nonprobability purposive sampling technique was used for this study. Arrest factor score was used to assess prognosis of IHCA. Statistical analysis used: Descriptive statistics to determine the frequency and distribution, multiple regression analysis to interpret the data, and Chi-square test for associating the variables. Results: Percentage distribution of arrest factors determines the cardiac cause 94.4% and noncardiac cause 89.6%, and cardiopulmonary resuscitation was carried for 2 to 4 minutes (2.4%) duration, 5 to 9 minutes (15.2%), 15 to 19 minutes (8.8%), 20 to 24 minutes (17.6%), 25 to 29 minutes (32%), and ≥30 minutes (24%) among patients with IHCA. Frequency and distribution of arrest factors were increased survival outcome 0 (0.0%), moderate survival outcome 33 (26.4%), and decreased survival outcome 92 (73.6%) in survival outcome among patients with IHCA. The P-values corresponding to “total cholesterol level and low-density lipoprotein cholesterol level” at 0.01 level and “triglycerides and smoking” at 0.05 level are highly impacting the “arrest factors scores.” Conclusion: Determining cardiac and noncardiac causes can determine the risk of IHCA. Identification and early management and duration of CPR initiate the reversal of IHCA and increase the rate of survival outcome.

The effect of the head-up position on cardiopulmonary resuscitation: a systematic review and meta-analysis

ObjectiveExperimental studies of head-up positioning (HUP) during cardiopulmonary resuscitation (CPR) have had some degree of conflicting published results. The current study aim was to analyze and reconcile those discrepancies in order to better clarify the effects of HUP CPR compared to conventional supine (SUP) CPR.MethodsThree databases (PubMed, EMBASE and Cochrane Library) were searched comprehensively (from each respective database's inception to May 2021) for articles addressing HUP CPR. The primary outcome to be observed was cerebral perfusion pressure (CerPP), and secondary outcomes were mean intracranial pressure (ICP), mean arterial pressure (MAP), coronary perfusion pressure (CoPP) and frequencies of return of spontaneous circulation (ROSC).ResultsSeven key studies involving 131 animals were included for analysis. Compared to SUP CPR, CerPP (MD 10.37; 95% CI 7.11–13.64; p < 0.01; I2 = 58%) and CoPP (MD 7.56; 95% CI 1.84–13.27, p = 0.01; I2 = 75%) increased significantly with HUP CPR, while ICP (MD − 13.66; 95% CI − 18.6 to –8.71; p < 0.01; I2 = 96%) decreased significantly. Combining all study methodologies, there were no significant differences detected in MAP (MD − 1.63; 95% CI − 10.77–7.52; p = 0.73; I2 = 93%) or frequency of ROSC (RR 0.9; 95% CI 0.31–2.60; p = 0.84; I2 = 65%). However, in contrast to worse outcomes in studies using immediate elevation of the head in a reverse Trendelenburg position, study outcomes were significantly improved when HUP (head and chest only) was introduced in a steady, graduated manner following a brief period of basic CPR augmented by active compression–decompression (ACD) and impedance threshold (ITD) devices.ConclusionIn experimental models, gradually elevating the head and chest following a brief interval of circulatory priming with ACD and ITD devices can enhance CoPP, lower ICP and improve CerPP significantly while maintaining MAP. This effect is immediate, remains sustained and is associated with improved outcomes.

Compression depth of 30 mm has similar efficacy and fewer complications versus 50 mm during mechanical chest compression with miniaturized chest compressor in a porcine model of cardiac arrest.

BackgroundCurrent guidelines recommend a 50 mm or greater compression depth for manual chest compression in adults. However, whether this uniform compression depth is a suitable requirement for mechanical CPR remains to be determined. We hypothesized that a relatively shallow compression depth (30 mm) would have similar hemodynamic efficacy but fewer complications versus the standard compression depth (50 mm) during mechanical cardiopulmonary resuscitation (CPR) with the miniaturized chest compressor (MCC) in a porcine model.MethodsIn the current study, we used a total of 16 domestic male pigs (38±2 kg). All pigs were exposed to 7 min of ventricular fibrillation (VF) followed by 5 min of CPR. Then the animals were randomly assigned to the shallow (30 mm) group and the standard (50 mm) group. At the second min of CPR, every pig was given epinephrine (20 µg/kg) through the femoral vein and repeated every 3 min. First defibrillation was delivered with a single 120 J shock at 5 min of CPR. Hemodynamics, carotid blood flow (CBF), end-tidal carbon dioxide (ETCO2), coronary perfusion pressure (CPP), intrathoracic pressure (ITP) and arterial blood gas were measured. Rib fractures and lung injuries, as indicated by ground-glass opacification (GGO), as well as intense parenchymal opacification (IPO), were assessed and calculated by quantitative computed tomography (QCT) scan.ResultsWe found no significant differences in CPP, CBF, or ETCO2 between the both groups throughout the CPR period. After administration of epinephrine, the CPP of all animals increased while ETCO2 and CBF decreased during CPR. A significantly lower intrathoracic positive pressure (ITPP) and systolic artery pressure (SAP) were measured in the shallow group at the first min of CPR. However, we didn’t find remarkable differences in these values between the both groups for the next 4 min of CPR. All animals were successfully resuscitated. The shallow group had significantly lower IPO QCT scores compared with the standard group. We found no significant differences in GGO QCT scores after resuscitation between both groups.ConclusionsRelatively shallow compression depth has similar hemodynamic efficacy but fewer complications versus the standard compression depth.

Rewarming With Closed Thoracic Lavage Following 3-h CPR at 27°C Failed to Reestablish a Perfusing Rhythm.

Introduction: Previously, we showed that the cardiopulmonary resuscitation (CPR) for hypothermic cardiac arrest (HCA) maintained cardiac output (CO) and mean arterial pressure (MAP) to the same reduced level during normothermia (38°C) vs. hypothermia (27°C). In addition, at 27°C, the CPR for 3-h provided global O2 delivery (DO2) to support aerobic metabolism. The present study investigated if rewarming with closed thoracic lavage induces a perfusing rhythm after 3-h continuous CPR at 27°C.Materials and Methods: Eight male pigs were anesthetized, and immersion-cooled. At 27°C, HCA was electrically induced, CPR was started and continued for a 3-h period. Thereafter, the animals were rewarmed by combining closed thoracic lavage and continued CPR. Organ blood flow was measured using microspheres.Results: After cooling with spontaneous circulation to 27°C, MAP and CO were initially reduced by 37 and 58% from baseline, respectively. By 15 min after the onset of CPR, MAP, and CO were further reduced by 58 and 77% from baseline, respectively, which remained unchanged throughout the rest of the 3-h period of CPR. During CPR at 27°C, DO2 and O2 extraction rate (VO2) fell to critically low levels, but the simultaneous small increase in lactate and a modest reduction in pH, indicated the presence of maintained aerobic metabolism. During rewarming with closed thoracic lavage, all animals displayed ventricular fibrillation, but only one animal could be electro-converted to restore a short-lived perfusing rhythm. Rewarming ended in circulatory collapse in all the animals at 38°C.Conclusion: The CPR for 3-h at 27°C managed to sustain lower levels of CO and MAP sufficient to support global DO2. Rewarming accidental hypothermia patients following prolonged CPR for HCA with closed thoracic lavage is not an alternative to rewarming by extra-corporeal life support as these patients are often in need of massive cardio-pulmonary support during as well as after rewarming.

Evaluation of a revised resuscitation protocol for out-of-hospital cardiac arrest patients due to COVID-19 safety protocols: a single-center retrospective study in Japan

This study aimed to determine the association between cardiopulmonary resuscitation (CPR) under the coronavirus 2019 (COVID-19) safety protocols in our hospital and the prognosis of out-of-hospital cardiac arrest (OHCA) patients, in an urban area, where the prevalence of COVID-19 infection is relatively low. This was a single-center, retrospective, observational, cohort study conducted at a tertiary critical care center in Kyoto City, Japan. Adult OHCA patients arriving at our hospital under CPR between January 1, 2019, and December 31, 2020 were included. Our hospital implemented a revised resuscitation protocol for OHCA patients on April 1, 2020 to prevent COVID-19 transmission. This study defined the conventional CPR period as January 1, 2019 to March 31, 2020, and the COVID-19 safety protocol period as April 1, 2020 to December 31, 2020. Throughout the prehospital and in-hospital settings, resuscitation protocols about wearing personal protective equipment and airway management were revised in order to minimize the risk of infection; otherwise, the other resuscitation management had not been changed. The primary outcome was hospitalization survival. The secondary outcomes were return of spontaneous circulation after hospital arrival and 1-month survival after OHCA occurrence. The adjusted odds ratios with 95% confidence intervals (CI) were calculated for outcomes to compare the two study periods, and the multivariable logistic model was used to adjust for potential confounders. The study analyzed 443 patients, with a median age of 76 years (65–85), and included 261 men (58.9%). The percentage of hospitalization survivors during the entire research period was 16.9% (75/443 patients), with 18.7% (50/267) during the conventional CPR period and 14.2% (25/176) during the COVID-19 safety protocol period. The adjusted odds ratio for hospitalization survival during the COVID-19 safety protocol period was 0.61 (95% CI 0.32–1.18), as compared with conventional CPR. There were no cases of COVID-19 infection among the staff involved in the resuscitation in our hospital. There was no apparent difference in hospitalization survival between the OHCA patients resuscitated under the conventional CPR protocol compared with the current revised protocol for controlling COVID-19 transmission.

Correlation of EEG-based brain resuscitation index and end-tidal carbon dioxide in porcine cardiac arrest model

Evaluation and monitoring perfusion of vital organs is important during resuscitation from cardiac arrest. We developed a non-invasive electroencephalogram (EEG) based brain resuscitation index (EBRI) as a physiologic indicator measuring organ perfusion during cardiopulmonary resuscitation (CPR) and evaluated the correlation of EBRI and end-tidal carbon dioxide (ETCO2). A randomized crossover experimental study using a porcine cardiac arrest model was designed. After 1 minute of untreated ventricular fibrillation, 10 periods of higher-quality CPR (compression depth 5 cm and compression rate 100/min) for 50 seconds and lower-quality CPR (compression depth 3 cm and compression rate 60/min) for 50 seconds were performed in alternation. EBRI was calculated from the single EEG channel with the lowest noise. Mixed-model analysis was conducted to compare the differences of hemodynamic parameters, ETCO2, and EBRI between higher-quality CPR periods and lower-quality CPR periods. Pearson’s correlation coefficient was calculated to assess correlation between EBRI and ETCO2. The experiment was performed on 5 female swine (44.6 ± 2.8 kg). Higher-quality CPR showed significantly higher delta EBRI (median [IQR] 0.1 [0.0–0.2]) than did lower-quality CPR (median [IQR] –0.1 [–0.2–0.0], p &lt; 0.01). EBRI had a statistically moderate positive correlation with ETCO2 (r = 0.51). In this porcine cardiac arrest model, EBRI was successfully obtained during resuscitation and had a statistically moderate correlation with ETCO2.

Abstract 298: Predicting Pulse Status During Cardiopulmonary Resuscitation Using Dimensionality Reduction of Electrocardiogram Wavelet Transforms

Background: Current resuscitation protocols require pausing cardiopulmonary resuscitation (CPR) to check for a pulse. However, pausing CPR during a pulseless rhythm worsens patient outcome. We designed an ECG-based algorithm that predicts pulse status during uninterrupted CPR, and evaluated its performance both with and without CPR. Methods: We evaluated 383 patients who were treated for out-of-hospital cardiac arrest using defibrillators with real-time ECG, CPR, and audio recordings. We collected paired adjacent ECG segments with and without CPR during organized rhythms. Segments were collected during the 10-s CPR period just prior to pulse check, and 5-s segments without CPR during the pulse check. ECG segments with or without a pulse were identified by the audio annotation and recorded blood pressures. Patients were randomly divided into 60% (230/383) training and 40% (153/383) test groups. From training data, we developed an algorithm to predict clinical pulse status based on the wavelet transform of the bandpass-filtered ECG, applying principle component analysis (PCA). We then trained a linear discriminant model using 3 principle component modes as input features. Model performance was evaluated on test group segments with and without CPR using receiver operating curves overall and according to initial arrest rhythm. Results: There were 230 patients (540 pulse checks) in the training set and 153 patients (372 pulse checks) in the test set. In both of these sets, about 16% (37/230 and 25/153) of the patients presented with initial non-shockable rhythm . Overall 38% (351/912) of checks had a spontaneous pulse. The areas under the receiver operating characteristic curve (AUCs) for predicting pulse status with and without CPR on test data were 0.84 and 0.89, respectively. Conclusion: A novel ECG-based algorithm demonstrates potential to improve resuscitation by predicting presence of a spontaneous pulse without pausing CPR.

Refractory pelvic fracture-associated hemorrhage after preperitoneal packing: now what?

A male patient in his 50s presented after a high-speed motorcycle crash. On arrival to the trauma bay, his primary survey was intact with normal vital signs. He had an...

Optimal paramedic numbers in resuscitation of patients with out-of-hospital cardiac arrest: A randomized controlled study in a simulation setting.

The effect of paramedic crew size in the resuscitation of patients with out-of-hospital cardiac arrest (OHCA) remains inconclusive. We hypothesised that teams with a larger crew size have better resuscitation performance including chest compression fraction (CCF), advanced life support (ALS), and teamwork performance than those with a smaller crew size. We conducted a randomized controlled study in a simulation setting. A total of 140 paramedics from New Taipei City were obtained by stratified sampling and were randomly allocated to 35 teams with crew sizes of 2, 3, 4, 5, and 6 (i.e. 7 teams in every paramedic crew size). A scenario involving an OHCA patient who experienced ventricular fibrillation and was attached to a cardiopulmonary resuscitation (CPR) machine was simulated. The primary outcome was the overall CCF; the secondary outcomes were the CCF in manual CPR periods, time from the first dose of epinephrine until the accomplishment of intubation, and teamwork performance. Tasks affecting the hands-off time during CPR were also analysed. In all 35 teams with crew sizes of 2, 3, 4, 5, and 6, the overall CCFs were 65.1%, 64.4%, 70.7%, 72.8%, and 71.5%, respectively (P = 0.148). Teams with a crew size of 5 (58.4%, 61.8%, 68.9%, 72.4%, and 68.7%, P<0.05) had higher CCF in manual CPR periods and better team dynamics. Time to the first dose of epinephrine was significantly shorter in teams with 4 paramedics, while time to completion of intubation was shortest in teams with 6 paramedics. Troubleshooting of M-CPR machine decreased the hands-off time during resuscitation (39 s), with teams comprising 2 paramedics having the longest hands-off time (63s). Larger paramedic crew size (≧4 paramedics) did not significantly increase the overall CCF in OHCA resuscitation but showed higher CCF in manual CPR period before the setup of the CPR machine. A crew size of ≧4 paramedics can also shorten the time of ALS interventions, while teams with 5 paramedics will have the best teamwork performance. Paramedic teams with a smaller crew size should focus more on the quality of manual CPR, teamwork, and training how to troubleshoot a M-CPR machine.

Abstract 481: Cardiopulmonary Resuscitation: The Effect of Fatigue on Professional Rescuers During Continuous Chest Compressions

Introduction: It is reported that quality of chest compressions (CC) during cardiopulmonary resuscitation (CPR) for both professional and non-professional rescuers often do not meet guideline requirements. Devices which provide feedback on the quality of CCs are designed to reduce the incidence of suboptimal compressions and promote the administration of effective CCs. Objective: This analysis investigates the effect of CPR duration on the performance of continuous CCs delivered by professional rescuers. Methods: Data were collected from a first responder group based in Texas, USA. Responders were instructed to use a CPR depth feedback device (Laerdal CPRmeter) and an automatic external defibrillator (AED; HeartSine SAM 350P) when attending sudden cardiac arrest events. The AED was configured with a shock protocol separated by 2-minute episodes of CPR and rescuer CC depth and rate were guided by the CPR depth feedback device. CC depth and rate data were processed for 174 patient events. Each CPR episode was divided into 4-analysis windows, 30-seconds in duration. Mean CC depth and rate data was calculated for each window. There were 1433 observations of CC depth and rate available for analysis across 414 CPR episodes. The data was fitted by a multiple linear regression model to assess the effect of CPR duration on CC performance. Results: The mean CC depth at the beginning of an event was 49.01 +/-0.51 mm. CC depth decreased by 0.82 mm, for each passing 30-second interval (p &lt; 0.001). The mean CC rate at the beginning of an event was 111.17 +/- 0.33 compression per minute (CPM). No significant difference was observed between CC rate and duration of continuous CCs (p = 0.896) however there was a significant increase in CC rate observed of 0.408 CPM for each elapsed 2-minute CPR episode (p = 0.011). Conclusion: A reduction in CC depth was observed within each CPR episode, which may be indicative of fatigue during continuous CCs. Although a reduction of 3.28 mm throughout a 2-minute period of CPR may be clinically insignificant, this effect was observed within a trained rescuer group with CPR feedback. Further research is required to assess the effect of fatigue in non-professional responders.

Acute muscle fatigue and CPR quality assisted by visual feedback devices: A randomized-crossover simulation trial.

ObjectiveTo analyse the acute muscular fatigue (AMF) in triceps brachii and rectus abdominis during compression-only and standard cardiopulmonary resuscitation (CPR) performed by certified basic life support providers.MethodsTwenty-six subjects were initially recruited and randomly allocated to two study groups according to the muscles analysed; eighteen finally met the inclusion criteria (nine in each group). Both groups carried out two CPR tests (compression-only and standard CPR) of 10 min divided into five 2-min intermittent periods. The ventilation method was freely chosen by each participant (mouth-to-mouth, pocket-mask or bag-valve-mask). CPR feedback was provided all the time. AMF was measured by tensiomyography at baseline and after each 2-min period of the CPR test, in triceps brachii or rectus abdominis according to the study group.ResultsRectus abdominis’ contraction time increased significantly during the fifth CPR period (p = 0.020). Triceps brachii’s radial muscle belly displacement (p = 0.047) and contraction velocity (p = 0.018) were lower during compression-only CPR than during standard CPR. Participants who had trained previously with feedback devices achieved better CPR quality results in both protocols. Half of participants chose bag-valve-mask to perform ventilations but attained lower significant ventilation quality than the other subjects.ConclusionsCompression-only CPR induces higher AMF than standard CPR. Significantly higher fatigue levels were found during the fifth CPR test period, regardless of the method. Adequate rescuer’s strength seems to be a requisite to take advantage of CPR quality feedback devices. Training should put more emphasis on the quality of ventilation during CPR.

Full neurological recovery following a hypothermic, near-drowning cardiac arrest with a 34 minute submersion time: A case repor

Hypothermia increases the ischemic tolerance of the brain and can lead to a remarkable recovery in prolonged cardiac arrest. Neurological outcomes can be very favorable, particularly if cardiac arrest precedes hypothermia or if the onset of hypothermia following cardiac arrest is rapid. Case reports of good neurological recovery following up to 7 h submersion and core temperatures as low as 13.7°C can be found. Our case involved a 43-year-old male who presented following a collapse and out of hospital cardiac arrest. A 34 min period of face-down submersion in a canal on a cold February evening was followed by a brief period of cardiopulmonary resuscitation on extrication. He was transferred to our emergency department with a core temperature of 26°C. He went onto make a full neurological recovery. The UK’s temperate climate means that case reports of prolonged hypothermic cardiac arrest are rare. While this gentleman had many favorable circumstances to his predicament, including age, cardiovascular fitness and rapid cooling, prompt and effective resuscitation, and a controlled warming regime would also have contributed. Keywords: Hypothermia cardiac arrest, neurological recovery.

Use of resuscitation plans at a tertiary Australian hospital: room for improvement.

The 'Acute Resuscitation Plan' (ARP) is a document for recording the resuscitation plans of patients at a tertiary hospital for adult patients. The ARP was introduced at the hospital in September 2014, superseding the 'Not for Cardiopulmonary Resuscitation (CPR)' form. Unlike the Not for CPR form, the ARP was relevant to patients with and without resuscitation limits. To evaluate the introduction of the ARP. This study is a retrospective audit of the records of all admissions to the hospital from January to June 2014 (Not for CPR period) and January to June 2015 (ARP period). The main outcomes are the incidence of resuscitation plans, the proportion of ARP specifying consultation with the patient (or representative) and with senior medical staff, and the proportion of ARP among older patients and those with significant comorbidity. Resuscitation plans were present for 453 of 23 325 (1.9%) admissions in the Not for CPR period versus 1801 of 24 037 (7.5%) in the ARP period (odds ratio (OR) 4.1, 95% confidence interval (CI) 3.7-4.5, P < 0.001). A total of 42% of ARP specified 'care of the dying' in the event of arrest. Acknowledgement of the views of the patient (or representative) was indicated on 37% of ARP and of a senior physician on 28%. An ARP was not present for 67% of patients aged ≥90 years, 59% from aged care, 90% with metastatic cancer and 64% aged ≥80 years and with a Charlson comorbidity index ≥3. More patients had resuscitation plans after introducing the ARP. However, patients and senior physicians were often remote from the consultation process, and an ARP was not present for many patients likely to have a poor outcome from cardiopulmonary arrest.