Standard Cardiopulmonary Resuscitation Group Research Articles

COMPARISON BETWEEN ACTIVE ABDOMINAL COMPRESSION-DECOMPRESSION CARDIOPULMONARY RESUSCITATION AND STANDARD CARDIOPULMONARY RESUSCITATION IN ASPHYCTIC CARDIAC ARREST RATS WITH MULTIPLE RIB FRACTURES.

Background: Active abdominal compression-decompression cardiopulmonary resuscitation (AACD-CPR) is potentially more effective for cardiac arrest (CA) with multiple rib fractures. However, its effect on survival rates and neurological outcomes remains unknown. This study aimed to assess if AACD-CPR improves survival rates and neurological outcomes in a rat model of asphyctic CA with multiple rib fractures. Methods: Adult male Sprague-Dawley rats were randomized into three groups-AACD group (n = 15), standard cardiopulmonary resuscitation (STD-CPR) group (n = 15), and sham group (n = 10)-after bilateral rib fractures were surgically created and endotracheal intubation was performed. AACD-CPR and STD-CPR groups underwent 8 min of asphyxia followed by different CPR techniques. The sham group had venous catheterization only. Physiological variables and arterial blood gases were recorded at baseline and during a 4-h monitoring period. Neurological deficit scores (NDSs) and cumulative survival rates were assessed at 24, 48, and 72 h. NDS, serum biomarkers, and hippocampal neuron analysis were used to evaluate neurological outcomes. Results: No statistical differences were observed in the return of spontaneous circulation (ROSC), 24-, 48-, and 72-h survival rates between the AACD-CPR and STD-CPR groups. AACD-CPR rats had lower serum levels of neuron-specific enolase and S100B at 72 h post-ROSC, and higher NDS at 72 h post-ROSC compared with STD-CPR animals. Cellular morphology analysis, hematoxylin and eosin staining, and TUNEL/DAPI assays showed more viable neurons and fewer apoptotic neurons in the AACD-CPR group than in the STD-CPR group. Conclusions: AACD-CPR can achieve similar survival rates and better neurological outcome after asphyxial CA in rats with multiple rib fractures when compared with STD-CPR.

Impact of limbs pneumatic compression during cardiopulmonary resuscitation (CPR) on cardiac arrest patients: a randomized controlled trial

Abstract Background Limbs pneumatic compression during cardiopulmonary resuscitation (CPR) for cardiac arrest patient were rarely reported. Purpose To evaluate the effect of this therapy on the patients of cardiac arrest. Methods A randomized, controlled and trial, a total of 62 elderly (75.8±8.3 yrs) cardiac arrest patients were included and randomized to “CPR group” (n=31) and “CPR + Pneumatic Compression group” (n=31). Each individual in CPR group received standard CPR. In addition to the standard CPR, all patients in “Pneumatic Compression group” accepted intermittent pneumatic compression (IPC) by Air Compression Therapy System, which digital six-tiered rippling full-body pressure (0.45–0.6 kg/cm2) and 1 minute interval every 5 minutes. Results Compared with standard CPR group, significant improvements of cardiac output (CO) and survival of patient were found in Pneumatic Compression group (Figure 1). Patients with pneumatic compression had lower incidence (19.4% vs. 45.2%, p=0.03) of acute kidney injury (AKI) than that in standard CPR group. Besides, the lower occurrence of hypoxic ischemic encephalopathy (HIE) was observed in Pneumatic Compression group (Figure 2). There was no ischemic myonecrosis of limbs caused by compression. Conclusions Intermittent limbs pneumatic compression during cardiopulmonary resuscitation (CPR) maybe could improve the blood flow of the crucial organs (e.g. brain) and increase survival of cardiac arrest patients, which is superior to the strategy for CPR alone. Funding Acknowledgement Type of funding sources: Public hospital(s). Main funding source(s): SHOU FA2020-4-1045 Fundation

IMPACT OF LIMBS PNEUMATIC COMPRESSION DURING CPR ON SURVIVAL OF CARDIAC ARREST

SESSION TITLE: Analyzing What We Do in the ICUSESSION TYPE: Rapid Fire Original InvPRESENTED ON: 10/17/2022 12:15 pm - 1:15 pmPURPOSE: Limbs pneumatic compression during cardiopulmonary resuscitation (CPR) for cardiac arrest patient were rarely reported. We aimed to evaluate the impact of this therapy on the patient with cardiac arrest.METHODS: It was a prospective and controlled study, a total of 46 elderly(74.8±5.3 yrs) cardiac arrest patients were included and randomized to “CPR group “(n=23) and “CPR + Pneumatic Compression group” (n=23). Each patient in CPR group accepted standard CPR. In addition to standard CPR, all subjects in “Pneumatic Compression group” received intermittent pneumatic compression(IPC) by Air Compression Therapy System, which digital six-tiered rippling full-body pressure (0.45~0.6kg/cm2) and 1 minute interval every 3 minutes.RESULTS: Patients with standard CPR had higher incidence of acute kidney injury(AKI)than in “CPR + Pneumatic Compression group” (52.2% vs. 21.7%,p=0.032).Besides, the lower occurrence of hypoxic ischemic encephalopathy(HIE) was observed in Pneumatic Compression group(Figure 1) . Compared to standard CPR group, significant improvements of cardiac output(CO) and survival of patient were observed in Pneumatic Compression group(Figure 2). The average blood velocity of femoral vein during intermittent period was 4.2±1.7cm/s and 3.8±1.2cm/s in “CPR group” and “CPR + Pneumatic Compression group” respectively (p=0.361).CONCLUSIONS: Intermittent limbs pneumatic compression during cardiopulmonary resuscitation(CPR) maybe improve survival of cardiac arrest.CLINICAL IMPLICATIONS: Limbs pneumatic compression maybe could improve clinical outcomes of cardiopulmonary resuscitation by enhancing the blood flow of the crucial organs(e.g. brain) ,it seems to be an optimizing strategy for CPR, and which need further study.DISCLOSURES: No relevant relationships by Boxue Han SESSION TITLE: Analyzing What We Do in the ICU SESSION TYPE: Rapid Fire Original Inv PRESENTED ON: 10/17/2022 12:15 pm - 1:15 pm PURPOSE: Limbs pneumatic compression during cardiopulmonary resuscitation (CPR) for cardiac arrest patient were rarely reported. We aimed to evaluate the impact of this therapy on the patient with cardiac arrest. METHODS: It was a prospective and controlled study, a total of 46 elderly(74.8±5.3 yrs) cardiac arrest patients were included and randomized to “CPR group “(n=23) and “CPR + Pneumatic Compression group” (n=23). Each patient in CPR group accepted standard CPR. In addition to standard CPR, all subjects in “Pneumatic Compression group” received intermittent pneumatic compression(IPC) by Air Compression Therapy System, which digital six-tiered rippling full-body pressure (0.45~0.6kg/cm2) and 1 minute interval every 3 minutes. RESULTS: Patients with standard CPR had higher incidence of acute kidney injury(AKI)than in “CPR + Pneumatic Compression group” (52.2% vs. 21.7%,p=0.032).Besides, the lower occurrence of hypoxic ischemic encephalopathy(HIE) was observed in Pneumatic Compression group(Figure 1) . Compared to standard CPR group, significant improvements of cardiac output(CO) and survival of patient were observed in Pneumatic Compression group(Figure 2). The average blood velocity of femoral vein during intermittent period was 4.2±1.7cm/s and 3.8±1.2cm/s in “CPR group” and “CPR + Pneumatic Compression group” respectively (p=0.361). CONCLUSIONS: Intermittent limbs pneumatic compression during cardiopulmonary resuscitation(CPR) maybe improve survival of cardiac arrest. CLINICAL IMPLICATIONS: Limbs pneumatic compression maybe could improve clinical outcomes of cardiopulmonary resuscitation by enhancing the blood flow of the crucial organs(e.g. brain) ,it seems to be an optimizing strategy for CPR, and which need further study. DISCLOSURES: No relevant relationships by Boxue Han

Evaluation of abdominal compression–decompression combined with chest compression CPR performed by a new device: Is the prognosis improved after this combination CPR technique?

IntroductionThis study was designed to compare the outcomes of standard cardiopulmonary resuscitation (STD-CPR) and combined chest compression and abdominal compression–decompression cardiopulmonary resuscitation (CO-CPR) with a new device following out-of-hospital cardiac arrest (OHCA). Moreover, we investigated whether patient prognosis improved with this combination treatment.MethodsThis trial was a single-centre, prospective, randomized trial, and a blinded assessment of the outcomes was performed. A total of 297 consecutive patients with OHCA were initially screened, and 278 were randomized to the STD-CPR group (n = 135) or the CO-CPR group (n = 143). We compared the proportions of patients who achieved a return of spontaneous circulation (ROSC), survived to hospital admission and survived to hospital discharge. In addition, we also performed the Kaplan–Meier analysis with a log-rank test at the end of the follow-up period to compare the survival curves of the two groups.ResultsThe differences were not statistically significant in the proportion of patients who achieved ROSC [31/135 (23.0%) versus 35/143 (24.5%)] and survived to hospital admission [28/135 (20.7%) versus 33/143 (23.1%)] between the CO-CPR group and STD-CPR group. However, there was a significant difference in the proportion of patients who survived to hospital discharge [16/135 (11.9%) versus 7/143 (4.9%)] between the two groups. Nine patients (6.7%) in the CO-CPR group and 2 patients (1.4%) in the STD group showed good neurological outcomes according to the cerebral performance category (CPC) scale score, and the difference was statistically significant (P = 0.003). The Kaplan–Meier curves showed that the patients in the CO-CPR group achieved better survival benefits than those in the STD-CPR group at the end of the follow-up period (log-rank P = 0.007).ConclusionCO-CPR was more beneficial than STD-CPR in terms of survival benefits in patients who have suffered out-of-hospital cardiac arrest.Trial registration Chinese Clinical Trial Registry, registered number: ChiCTR2100049581. Registered 30 July 2021- Retrospectively registered. http://www.medresman.org.cn/uc/index.aspx.

Effect of Interposed Abdominal Compression on Cardiopulmonary Resuscitation Outcomes; a Randomized Clinical Trial.

Introduction:Standard cardiopulmonary resuscitation (STD-CPR) is successful in only 10-15% of cases in emergency department (ED). This study aimed to determine the effect of interposed abdominal compression (IAC) during resuscitation on outcomes of ED cardiac arrests.Methods:In this randomized clinical trial study, non-trauma patients aged 18-85 years, patients with in-hospital cardiac arrest hospitalized in the ED were randomly assigned into two either STD-CPR or IAC-CPR group on a 1:1 basis and using computer-generated random numbers. Participants in the intervention group, received abdominal compression during the diastole phase of STD-CPR. The rate of return of spontaneous circulation (ROSC), heart rate (HR), respiratory rate (RR), arterial blood gas (ABG) indicators, and survival rate were compared between the two groups. Results:Ninety patients were enrolled (45 in each group). There were no differences between the two groups regarding age (p = 0.76), sex (p = 0.39), employment status (p = 0.62) and Charlson comorbidity scale (p = 0.46). Abdominal compression had a positive effect on heart rate (p < 0.001), mean arterial pressure (p = 0.003), arterial blood oxygen pressure (p = 0.001), and arterial blood carbon dioxide pressure (p = 0.001) as well as a negative effect on arterial blood oxygen saturation (p = 0.029) 30 minutes after resuscitation. Out of the 90 CPR cases, 8 (17.7%) cases in intervention group and 8 (17.7%) cases in control group were successful, among which all of the 8 patients in the intervention group and 5 of the patients in the control group had been discharged from hospital without any complications. Conclusion: The results showed that abdominal compression during CPR can improve resuscitation outcomes in patients with cardiac arrest. Therefore, in order to use this technique, further research is recommended.

Use of an end-tidal carbon dioxide-guided algorithm during cardiopulmonary resuscitation improves short-term survival in paediatric swine

AimTo evaluate an algorithm that uses an end-tidal carbon dioxide (ETCO2) target of ≥ 30 torr to guide specific changes in chest compression rate and epinephrine administration during cardiopulmonary resuscitation (CPR) in paediatric swine. MethodsSwine underwent asphyxial cardiac arrest followed by resuscitation with either standard or ETCO2-guided algorithm CPR. The standard group received chest compressions at a rate of 100/min and epinephrine every 4 min during advanced life support consistent with the American Heart Association paediatric resuscitation guidelines. In the ETCO2-guided algorithm group, chest compression rate was increased by 10 compressions/min for every minute that the ETCO2 was < 30 torr, and the epinephrine administration interval was decreased to every 2 min if the ETCO2 remained < 30 torr. Short-term survival and physiologic data during active resuscitation were compared. ResultsShort-term survival was significantly greater in the ETCO2-guided algorithm CPR group than in the standard CPR group (16/28 [57.1%] versus 4/28 [14.3%]; p = 0.002). Additionally, the algorithm group had higher predicted mean ETCO2, chest compression rate, diastolic and mean arterial pressure, and myocardial perfusion pressure throughout resuscitation. Swine in the algorithm group also exhibited significantly greater improvement in diastolic and mean arterial pressure and cerebral perfusion pressure after the first dose of epinephrine than did those in the standard group. Incidence of resuscitation-related injuries was similar in the two groups. ConclusionsUse of a resuscitation algorithm with stepwise guidance for changes in the chest compression rate and epinephrine administration interval based on a goal ETCO2 level improved survival and intra-arrest hemodynamics in this porcine cardiac arrest model.

Effects of interposed abdominal pulling-pressing cardiopulmonary resuscitation on hemodynamics and oxygen metabolism in patients with cardiac arrest

To analyze the effect of interposed abdominal pulling-pressing cardiopulmonary resuscitation (IAPP-CPR) and standard cardiopulmonary resuscitation (S-CPR) on hemodynamics and oxygen metabolism in patients with cardiac arrest, and to evaluate the treatment effect of IAPP-CPR. The patients with cardiac arrest, cardiac arrest time less than 30 minutes, and with S-CPR indications admitted to intensive care unit (ICU) of the First People's Hospital of Lianyungang from January 2017 to January 2019 were enrolled. The patients were divided into IAPP-CPR group and S-CPR group according to whether the patients had IAPP-CPR indication or not. The patients in the S-CPR group were operated according to the 2015 American Heart Association (AHA) CPR guidelines; and the patients in the IAPP-CPR group received the IAPP-CPR on the basis of the S-CRP. During the relaxation period, the patients were subjected to abdominal lifting and compressing with amplitude of 4-5 cm, frequency of 100-120 times/min, and the time ratio of lifting to compressing was 1:1. Hemodynamic changes during resuscitation were recorded in the two groups. Hemodynamics, oxygen metabolism, arterial blood gas analysis and prognostic indicators were recorded at 30 minutes after successful resuscitation. During the study period, 77 patients were selected, 24 patients were excluded from giving up treatment and quitting, 53 patients were enrolled in the analysis finally, with 28 patients in the S-CPR group and 25 in the IAPP-CPR group. (1) The heart rate (HR), mean arterial pressure (MAP) and coronary perfusion pressure (CPP) showed an upward trend during resuscitation, and a more significant increase was shown in the IAPP-CPR group. (2) Hemodynamics after successful resuscitation: there were 16 patients with successful resuscitation in the IAPP-CPR group and 13 in the S-CPR group. The MAP, CPP, global ejection fraction (GEF) and stroke volume (SV) of patients with successful resuscitation at 30 minutes after resuscitation in the IAPP-CPR group were significantly higher than those in the S-CPR group [MAP mmHg (1 mmHg = 0.133 kPa): 52.88±3.11 vs. 39.39±4.62, CPP (mmHg): 36.56±6.89 vs. 29.61±6.92, GEF: 0.217±0.036 vs. 0.178±0.027, SV (mL): 38.43±5.25 vs. 32.92±8.28, all P < 0.05], but there was no significant difference in central venous pressure (CVP) or HR between the two groups. (3) Oxygen metabolism after successful resuscitation: the cardiac output (CO), arterial oxygen content (CaO2), oxygen transport (DO2) and oxygen consumption (VO2) of patients with successful resuscitation at 30 minutes after resuscitation in the IAPP-CPR group were significantly higher than those in the S-CPR group [CO (L/min): 2.23±0.38 vs. 1.99±0.29, CaO2 (mL/L): 158.0±11.8 vs. 141.4±8.2, DO2 (mL/L): 245.8±29.9 vs. 209.1±28.0, VO2 (mL/L): 138.2±24.9 vs. 112.8±18.1, all P < 0.05]. (4) Arterial blood gas after successful resuscitation: the values of the pH, arterial oxygen partial pressure (PaO2), arterial partial pressure of carbon dioxide (PaCO2), oxygenation index (PaO2/FiO2) and central venous oxygen saturation (ScvO2) of patients with successful resuscitation at 30 minutes after resuscitation in the IAPP-CPR were significantly higher than those in the S-CPR group [pH value: 7.13±0.22 vs. 7.00±0.23, PaO2 (mmHg): 73.68±13.80 vs. 65.32±15.32, PaCO2 (mmHg): 36.24±11.77 vs. 29.12±7.82, PaO2/FiO2 (mmHg): 73.68±13.80 vs. 65.32±15.32, ScvO2: 0.628±0.074 vs. 0.589±0.066, all P < 0.05], and the blood lactic acid (Lac) level was significantly lower than that in the S-CPR group (mmoL/L: 9.80±4.28 vs. 12.18±3.63, P < 0.05). (5) The patients in the IAPP-CPR group had a shorter time for cardiac arrest to restoration of spontaneous circulation (ROSC) than that in the S-CPR group (minutes: 10.63±2.94 vs. 14.54±3.84, P < 0.01), and the rate of ROSC, CPR successful rate and 28-day survival rate were significantly higher than those in the S-CPR group [64.0% (16/25) vs. 46.4% (13/28), 60.0% (15/25) vs. 28.6% (8/28), 52.0% (13/25) vs. 21.4% (6/28), all P < 0.05]. There was no significant difference in incidence of rib fracture between the IAPP-CPR and S-CPR groups [92.0% (23/25) vs. 89.3% (25/28), P > 0.05], and no abdominal bleeding was found in both group. IAPP-CPR can produce better hemodynamic effect during and after resuscitation than S-CPR, and oxygen metabolism and arterial blood gas analysis parameters at 30 minutes after resuscitation were better than S-CPR, with higher ROSC rate, CPR successful rate and 28-day survival rate, and no significant difference in complications between the two resuscitation methods.

Ultrasonic monitoring of carotid blood flow in interposed abdominal pulling-pressing cardiopulmonary resuscitation

To explore the difference in ultrasonic monitoring in carotid blood flow, resuscitation effects and prognosis between interposed abdominal pulling-pressing cardiopulmonary resuscitation (IAPP-CPR) and standard cardiopulmonary resuscitation (STD-CPR). Seventy-five cardiac arrest (CA) patients admitted to emergency department of Shijingshan Teaching Hospital of Capital Medical University from June 2015 to December 2017 were enrolled. The patients were divided into STD-CPR group and IAPP-CPR group according to the treatment orders of them and the desire of relatives. All patients were given persistent external compression, airway open, tube intubation, and mechanical ventilation, vasoactive drugs application, defibrillation if required. STD-CPR group was operated according to the 2015 American Heart Association (AHA) CPR guidelines. On the basis of the standard CPR, IAPP-CPR group was recovered using abdominal lifting and compressing CPR instrument to press down to lift the upper abdomen continuously, when the chest compressing relaxed (frequency 100 times/min, down and lift time ratio 1:1, compressing strength 50 kg, lifting strength 30 kg). The patients' gender, age and CA etiology were recorded in the two groups. The vital signs and blood flow of carotid artery were monitored with ultrasonic Doppler during the CPR. The return of spontaneous circulation (ROSC) rate and 48-hour survival rate were observed in patients. The influence factors of ROSC were screened by Logistic regression analysis. The data of 75 patients with CA were enrolled finally, with STD-CPR group of 38 patients and IAPP-CPR group of 37 patients. There were no significant differences in patients' gender, age or CA etiology between the two groups. Comparing with STD-CPR group, the peak blood flow velocity of carotid artery in IAPP-CPR group was speeded up significantly (cm/s: 107.16±13.75 vs. 78.99±14.77, P < 0.01), the overall blood flow volume of carotid artery was increased significantly (mL/min: 989.06±115.88 vs. 751.62±118.92, P < 0.01), but there was no significant difference in inner diameter of carotid artery between the two groups (mm: 4.55±0.25 vs. 4.61±0.21, P > 0.05). During the CPR, the mean arterial pressure (MAP) and the transcutaneous oxygen saturation (SpO2) in IAPP-CPR group were significantly higher than those of STD-CPR group, but no significant difference was found in heart rate between the two groups. Four patients in STD-CPR group got ROSC, and 3 survived over 48 hours (1 myocardial infarction patient died of ventricular fibrillation) while 6 patients in IAPP-CPR group got ROSC and survived over 48 hours. There was no significant difference in ROSC rate or 48-hour survival rate between the two groups, but data of IAPP-CPR group was slightly higher than that of STD-CPR group [ROSC rate: 16.22% (6/37) vs. 10.53% (4/38), 48-hour survival rate: 16.22% (6/37) vs. 7.89% (3/38), both P > 0.05]. Multivariate Logistic regression analysis showed that the higher the MAP during CPR, the greater the possibility of ROSC was [odds ratio (OR) = 1.361, 95% confidence interval (95%CI) = 1.182-1.669, P = 0.030]. IAPP-CPR was superior to traditional STD-CPR in improving arterial blood flow and resuscitation effect, but no superiority was found in ROSC rate and survival rate, which may be relate to the small number of patients that included in this study. More clinic trials are needed.

Interposed abdominal pulling-pressing cardiopulmonary resuscitation improve the resuscitation effect for patients with cardiac arrest

To study the impact of interposed abdominal pulling-pressing cardiopulmonary resuscitation (IAPP-CPR) for patients with cardiac arrest (CA). A prospective study was conducted. A total of 122 CA patients admitted to Department of Emergency of Shandong Provincial Mining Industry Group Company Central Hospital from July 2013 to December 2017 were enrolled. They were divided into standard cardiopulmonary resuscitation (S-CPR) group (n = 62) and IAPP-CPR group (n = 60) according to order of admission. The patients in S-CPR group received external cardiac compression, open airway, endotracheal intubation, mechanical ventilation, routine drug rescue, and defibrillation when ventricular fibrillation was found. And the patients in IAPP-CPR group received the IAPP-CPR on the basis of the routine chest compression. During the relaxation period, the patients were subjected to abdominal lifting and compressing with amplitude of 4-5 cm, frequency of 100 times/min, and the time ratio of lifting to compressing was 1:1. The data of demographics and clinical signs of patients were collected. The markers of respiratory and circulatory performance of all patients after CPR were determined. The rates of restoration of spontaneous circulation (ROSC), successful resuscitation, and the prognosis were recorded. With the success of CRP as the dependent variable, the factors with statistical significance showed by univariate analysis were used as the independent variable to carry out two classification Logistic regression analysis for screening the influence factors of CPR success. Receiver operating characteristic (ROC) curve was plotted to analyze the predictive value of various factors on the success of CPR. 122 patients were enrolled in the analysis. Compared with the S-CPR group, heart rate (HR), mean arterial pressure (MAP), arterial partial pressure of oxygen (PaO2), and end-tidal carbon dioxide partial pressure (PETCO2) were significantly increased at 30 minutes after CPR in IAPP-CPR group [HR (bpm): 66.3±11.5 vs. 53.1±12.6, MAP (mmHg, 1 mmHg = 0.133 kPa): 65.4±6.5 vs. 53.2±5.4, PaO2 (mmHg): 77.7±11.8 vs. 61.8±14.3, PETCO2 (mmHg): 45.5±9.6 vs. 31.8±8.2, all P < 0.05], and arterial partial pressure of carbon dioxide (PaCO2) and lactic acid (Lac) were significantly lowered [PaCO2 (mmHg): 46.7±6.2 vs. 57.9±9.5, Lac (mmol/L): 2.1±1.5 vs. 4.4±2.2, both P < 0.05]. The time of CA to ROSC in IAPP-CPR group was significantly shorter than that in S-CPR group (minutes: 6.3±1.8 vs. 11.2±1.4, P < 0.05), the ROSC rate and CPR success rate were significantly higher than those in S-CPR group [ROSC rate: 61.7% (37/60) vs. 43.5% (27/62), CPR success rate: 40.0% (24/60) vs. 21.0% (13/62), both P < 0.05], and 24-hour survival rate and survival and discharge rate of patients were significantly higher than those in the S-CPR group [24-hour survival rate: 46.7% (28/60) vs. 29.0% (18/62), survival and discharge rate: 20.0% (12/60) vs. 11.3% (7/62), both P < 0.05]. Logistic regression analysis showed that PaO2, PaCO2 and PETCO2 were the factors that affect the success of CPR [PaO2: β= -3.76, odds ratio (OR) = 0.23, 95% confidence interval (95%CI) = 0.12-0.86, P = 0.031; PaCO2: β= 1.41, OR = 4.09, 95%CI = 1.70-9.82, P = 0.002, PETCO2: β= 0.78, OR = 2.18, 95%CI = 1.42-3.35, P = 0.000]. ROC curve analysis showed that the above three factors had good predictive value for the success of CPR. The predictive value of PaCO2 and PETCO2 were better, the area under ROC curve (AUC) was 0.93 and 0.92, respectively, when the cut-off values was 46.7 mmHg and 48.8 mmHg, the sensitivity was 92.0%, 88.0%, respectively, and the specificity was both 94.3%. PaO2, PaCO2 and PETCO2 are the factors that influence the success of CPR. PaCO2 and PETCO2 have great value in predicting the success of CPR. Compared with the S-CPR group, IAPP-CPR group results in better hemodynamic and pulmonary ventilation effects, and remarkably improve ROSC and successful resuscitation. IAPP-CPR has obvious clinical value for CA patients.

Easy-to-learn cardiopulmonary resuscitation training programme: a randomised controlled trial on laypeople's resuscitation performance.

Simplifying the learning of cardiopulmonary resuscitation (CPR) is advocated to improve skill acquisition and retention. A simplified CPR training programme focusing on continuous chest compression, with a simple landmark tracing technique, was introduced to laypeople. The study aimed to examine the effectiveness of the simplified CPR training in improving lay rescuers' CPR performance as compared to standard CPR. A total of 85 laypeople (aged 21-60 years) were recruited and randomly assigned to undertake either a two-hour simplified or standard CPR training session. They were tested two months after the training on a simulated cardiac arrest scenario. Participants' performance on the sequence of CPR steps was observed and evaluated using a validated CPR algorithm checklist. The quality of chest compression and ventilation was assessed from the recording manikins. The simplified CPR group performed significantly better on the CPR algorithm when compared to the standard CPR group (p < 0.01). No significant difference was found between the groups in time taken to initiate CPR. However, a significantly higher number of compressions and proportion of adequate compressions was demonstrated by the simplified group than the standard group (p < 0.01). Hands-off time was significantly shorter in the simplified CPR group than in the standard CPR group (p < 0.001). Simplifying the learning of CPR by focusing on continuous chest compressions, with simple hand placement for chest compression, could lead to better acquisition and retention of CPR algorithms, and better quality of chest compressions than standard CPR.

Research to Observe the Hemodynamic Changes and Cardiac Function in Active Abdominal Compression-decompression Cardiopulmonary Resuscitation

Objective: Compare the hemodynamic changes and cardiac function between active abdominal compressiondecompression cardiopulmonary resuscitation and standard cardiopulmonary resuscitation. Methods: A prospective controlled trial was conducted. The patients staying in EICU or ICU were the study subjects which were divided into active abdominal compression-decompression cardiopulmonary resuscitation (AACD-CPR) group and standard cardiopulmonary resuscitation (STD-CPR) group randomly. Central venous pressure (CVP), diastolic blood pressure (DBP) and coronary perfusion pressure (CPP) were recorded continuously. Transesophageal echocardiography (TEE) was used to observe the cardiac valves and assess left ventricular end diastolic volume (LVEDV), left ventricular end systolic volume (LVESV), left ventricular ejection fraction (LVEF) during CPR. Results: During CPR, LVEDV of two groups both decreased compared with pre-cardiac arrest, which was not statistically significant(P>0.05). LVEDV in AACD-CPR group was larger than STD-CPR group during CPR. But there was not statistically significant (P>0.05). During CPR, LVESV of two groups both increased compared with pre-cardiac arrest, which was statistically significant(P<0.01). LVESV in AACD-CPR group was larger than STDCPR group?P<0.05). But there was not statistically significant(P>0.05). Both AACD-CPR group and STD-CPR group showed significantly decreased LVEF compared with pre-cardic arrest, of which the difference was statistically significant(P<0.01). LVEF in STD-CPR group was higher than AACD-CPR group and there was a tatistically significant difference between them?P<0.05). When compressing chest , mitral valve and tricuspid valve were open and aortic valve and pulmonary valve were closed during the 8 patients of the STD-CPR group. Conclusion: During chest compression, heart pump took effect in a part of patients. However, during abdominal compression, heart was just a channel that blood flowed. The cardiac function in STD-CPR was superior to AACDCPR. However, both of them can produce effective haemodynamics. So, we suggested that AACD-CPR could be used in the patients with the contraindication of STD-CPR.

Effects of active abdominal compression-decompression CPR on oxygen metabolism and prognosis in patients with cardiac arrest

To analyze the effect of active abdominal compression-decompression cardiopulmonary resuscitation (AACD-CPR) and standard cardiopulmonary resuscitation (STD-CPR) on oxygen metabolism and prognosis of patient with cardiac arrest (CA), and to evaluate the treatment effect of AACD-CPR. Patients with CA, CA time less than 30 minutes, and without STD-CPR and AACD-CPR contraindications admitted to the Zhengzhou People's Hospital from October 1st 2015 to May 31st 2017 were enrolled. The patients were divided into STD-CPR group and AACD-CPR group according to random number table. All patients were given the same rescue measures, if required to give defibrillation; STD-CPR group was operated according to the 2015 American Heart Association (AHA) CPR guidelines; AACD-CPR group was recovered using abdominal lifting and compression cardiopulmonary resuscitation instrument. The oxygen metabolism, hemodynamic, arterial blood gas and prognostic indicators were recorded in the two groups during the resuscitation. A total of 69 cases, with STD-CPR group of 34 cases and AACD-CPR group of 35 cases were enrolled finally. (1) The oxygen metabolism: during the recovery, compared with STD-CPR group, arterial blood oxygen content (CaO2), arterial-venous oxygen content difference (avDO2), the oxygen carrying capacity (DO2), oxygen consumption (VO2) in AACD-CPR group were significantly increased [CaO2 (mL/L): 156±15 vs. 142±19, avDO2 (mL/L): 83±14 vs. 73±13, DO2 (mL/min): 248±51 vs. 208±54, VO2 (mL/min): 134±29 vs. 118±32, all P < 0.05], but there were no significant differences in cardiac output (CO) and mixed venous oxygen content (CvO2). (2) Hemodynamic and arterial blood gas: there were no significant differences in the base values of the heart rate (HR), mean arterial pressure (MAP), pH value, pulse oxygen saturation (SpO2), arterial oxygen pressure (PaO2), arterial partial pressure of carbon dioxide (PaCO2), and blood lactate (Lac) between two groups. In the recovery process, MAP, pH value, SpO2, PaO2 of two groups were increased, while PaCO2 and Lac were decreased. Except MAP of STD-CPR group was slightly higher than AACD-CPR group, the change tendency of AACD-CPR group was more obvious in each index obviously [pH value difference: 0.10±0.15 vs. 0.02±0.13, SpO2 difference: 0.311±0.255 vs. 0.159±0.232, PaO2 difference (mmHg, 1 mmHg = 0.133 kPa): 12.96±21.84 vs. 3.01±13.56, PaCO2 difference (mmHg): -9.91±11.17 vs. -3.52±13.87, Lac value difference (mmol/L): -0.64±0.61 vs. -0.31±0.58, all P < 0.05]. (3) Prognosis: compared with STD-CPR group, the restoration of spontaneous circulation (ROSC) rate in AACD-CPR group was slightly increased (22.9% vs. 8.8%, P > 0.05), but the ROSC time in AACD-CPR group was significantly shortened (minutes: 9.59±2.67 vs. 11.83±3.05, P < 0.01), nerve function defect score (NDS) was significantly decreased at 1, 2 weeks (26.45±6.42 vs. 30.73±7.38, 19.25±6.27 vs. 22.64±5.63, both P < 0.05), and the 2-week survival was slightly increased (17.1% vs. 5.9%, P > 0.05). AACD-CPR is similar to STD-CPR in improving hemodynamics of CA patients, but has advantage in the blood oxygen supply for tissues and organs, and the neurological function prognosis is better.

Abstract 296: Determinants of Incidence of Ventricular Fibrillation as First Recorded Rhythm During Out-of-Hospital Cardiac Arrest and Association with Long-Term Neurological Outcomes: Observations from a Large Randomized Clinical Study

Background: We sought to identify the factors that were associated with higher incidence of VF and survival with good neurological function in the ResQ Trial patients that compared standard cardiopulmonary resuscitation (S-CPR) versus active compression decompression CPR with an inspiratory impedance threshold device (ACD+ITD) in patients with out of hospital cardiac arrest (OHCA). Methods: A retrospective analysis of a randomized multicenter clinical study of 1655 patients with OHCA. 88.3% (106/120) of the patients discharged with good neurological function [Modified Rankin Score (MRS)≤3] had a first recorded rhythm of ventricular fibrillation/pulseless ventricular tachycardia (VF). The first rhythm was recorded in 99.4% (1645/1655) of the cases about 9.5 minutes after 911 call, on average 3 minutes after the arrival of EMS on the scene and after CPR was performed for at least 2 minutes. Results: A total of 32.8% of the patients had VF as presenting rhythm and 42.8% received bystander CPR. Presence of bystander CPR was associated with a higher VF incidence only in the S-CPR group (40.8% versus 23.1% with no bystander, p=0.001) but survival was 7.6% versus 4.6% p=0.09. Presence or absence of bystander CPR let to similar VF incidence and survival in the ACD+ITD group 36.1% versus 33.9% and 9.0% versus 8.9% respectively, p&gt;0.2. After propensity adjustment for witnessed arrest, age &lt;67, gender, public location, bystander CPR lost significance. In the absence of bystander CPR, ACD+ITD significantly increased the incidence of first recorded VF compared to S-CPR from 106/459 (23.1%) to 164/484 (33.9%) [OR 1.71, 95% CI (1.27, 2.30), p&lt;0.001], and in patients with VF, return of spontaneous circulation increased from 65/459 (14.2%) to 104/484 (21.5%) [OR 1.66, 95% CI (1.16, 2.37), p=0.004], leading to an overall doubling of survival with MRS≤3 from 21/455 (4.6%) to 43/482 (8.9%) [OR 2.02, 95% CI (1.15, 3.65), p=0.009]. After propensity adjustment ACD+ITD remained a significant predictor of an MRS≤3, (p= 0.02). Conclusions: VF was the most important predictor of survival with MRS≤3. In the absence of bystander CPR, ACD+ITD increased VF incidence as the first recorded rhythm and doubled survival to hospital discharge with MRS≤3 compared to S-CPR.

Continuous chest compression cardiopulmonary resuscitation training promotes rescuer self-confidence and increased secondary training

Recent work suggests that delivery of continuous chest compression cardiopulmonary resuscitation is an acceptable layperson resuscitation strategy, although little is known about layperson preferences for training in continuous chest compression cardiopulmonary resuscitation. We hypothesized that continuous chest compression cardiopulmonary resuscitation education would lead to greater trainee confidence and would encourage wider dissemination of cardiopulmonary resuscitation skills compared to standard cardiopulmonary resuscitation training (30 compressions: two breaths). Prospective, multicenter randomized study. Three academic medical center inpatient wards. Adult family members or friends (≥ 18 yrs old) of inpatients admitted with cardiac-related diagnoses. In a multicenter randomized trial, family members of hospitalized patients were trained via the educational method of video self-instruction. Subjects were randomized to continuous chest compression cardiopulmonary resuscitation or standard cardiopulmonary resuscitation educational modes. Cardiopulmonary resuscitation performance data were collected using a cardiopulmonary resuscitation skill-reporting manikin. Trainee perspectives and secondary training rates were assessed through mixed qualitative and quantitative survey instruments. Chest compression performance was similar in both groups. The trainees in the continuous chest compression cardiopulmonary resuscitation group were significantly more likely to express a desire to share their training kit with others (152 of 207 [73%] vs. 133 of 199 [67%], p = .03). Subjects were contacted 1 month after initial enrollment to assess actual sharing, or "secondary training." Kits were shared with 2.0 ± 3.4 additional family members in the continuous chest compression cardiopulmonary resuscitation group vs. 1.2 ± 2.2 in the standard cardiopulmonary resuscitation group (p = .03). As a secondary result, trainees in the continuous chest compression cardiopulmonary resuscitation group were more likely to rate themselves "very comfortable" with the idea of using cardiopulmonary resuscitation skills in actual events than the standard cardiopulmonary resuscitation trainees (71 of 207 [34%] vs. 57 of 199 [28%], p = .08). Continuous chest compression cardiopulmonary resuscitation education resulted in a statistically significant increase in secondary training. This work suggests that implementation of video self-instruction training programs using continuous chest compression cardiopulmonary resuscitation may confer broader dissemination of life-saving skills and may promote rescuer comfort with newly acquired cardiopulmonary resuscitation knowledge. URL: http://clinicaltrials.gov. Unique identifier: NCT01260441.

Microstructure and ultrastructure changes of multiple organ tissue and hemodynamic effects in swine after cardiopulmonary resuscitation

Objective To investigate the microstructure and ultrastructure changes of cardiac muscle, pallium, lung, liver and kidney tissue and hemodynamic effects after the success of cardiac arrest (CA)-cardiopulmonary resuscitation(CPR) of swine. Method A total of 16 Beijing swine(weight 29 ～ 35 kg)were randomly (random number) divided into normal-control group ( n = 8) and standard CPR group ( n = 8). The swine of the former group were only given anesthetized and intubated, without ventricular fibrillation and CPR. The swine of the latter group were given standard CPR after 4 min of untreated VF, from 10 min after restoration of spontaneous cirkg) and keep for 6 h. And cardiac output (CO), left ventricular maximal rate of systolic pressure ( + dp/dtmax),maximum reduction of left ventricular diastolic velocity ( - dp/dtmax), heart rate (HR) and mean arterial pressure (MAP) of these animals before ventricular fibrillation and 0.5 h, 2 h, 4 h, 6 h after ROSC have been monitored.All swine were put to death after 6 h,and got their cardiac apex, pallium, left lung, right lobe of liver and upper pole of left kidney quickly for microstructure and ultrastructure studies. Statistical analysis was performed using two paired samples t test. Results At different time points after restoration of spontaneous circulation, the cardiac output (CO),left ventricular maximal rate of systolic pressure ( + dp/dtmax), maximum reduction of left ventricular diastolic velocity (- dp/dtmax) were significantly lower than before ventricular fibrillation, with significant difference ( P ＜ 0.05). And HR of different time points were increased significantly ( P ＜ 0.05), with no significantly difference between MAP of each time points ( P ＞ 0.05). Compared with the normal-control group, the cardiac muscle, pallium, lung, liver and kidney tissue of the swine in standard CPR group were found different degree of damages in their microstructure and ultrastructure sections. The damages of the cardiac muscle, pallium, and lung tissue were more obviously. Conclusions Sudden cardiac arrest(CA)-cardiopulmonary resuscitation(CPR) could cause different degree of damages and hemodynamic effects on the body, through our ROSC 6 h model, the damages of the cardiac muscle, pallium and lung were more severity, the damages of liver and kidney were lighter. Key words: Cardiac arrest; Cardiopulmonary resuscitation; Cardiac muscle; Pallium; Lung; Liver; Kidney; General pathology; Ultrastructure; Hemodynamics; Post-cardiac arrest syndrome; Post-resuscitation multiple organ dysfunction syndrome(PR-MODS)

Effects of active compression-decompression cardiopulmonary resuscitation on cardiac functions during ventricular fibrillation by two-dimensional echocardiography in dogs

Objective To compare the effect of active compression-decompression cardiopulmonary resuscitation(ACD-CPR) with standard- cardiopulmonary resuscitation(S-CPR) on ventricular function in a canine ventricular fibrillation model. Methods Ventricular fibrillation was induced in anesthetized and instrumented canine. Twenty-four dogs were randomly assigned to either ACD-CPR group or S-CPR group.After 4 minutes of untreated VF,two-dimension echocardiography was used to evaluate the left ventricular end-diastolic volume(LVEDV),left ventricular end-systolic volume(LVESV) and left ventricular ejection fraction (LVEF) of every canine of the two groups when they were undergoing cardiopulmonary resuscitation. Results During ventricular fibrillation, both ACD-CPR group and S-CPR group showed decreased LVEDV compared with pre-ventricular fibrillation, but not statistically significant( P ＞0.05).LVEDV was increased in ACD-CPR group compared with S-CPR group, but not statistically significant (P＞ 0. 05). Both ACD-CPR group and S-CPR group showed significantly increased LVESV compared with pre-ventricular fibrillation,of which the difference was statistically significant ( P ＜0. 001). Both ACD-CPRgroup and S-CPR group showed significantly decreased LVEF compared with pre-ventricular fibrillation,of which the difference was statistically significant (P ＜0. 001). LVEF was increased in ACD-CPR group compared with S-CPR group,of which the difference was statistically significant ( P = 0.019). Conclusions Compared with S-CPR,ACD-CPR resulted in higher LVEF. Key words: Echocardiography; Ventricular fibrillation; Cardiopulmonary resuscitation; Ventricular function, left

Survival and neurologic outcome after cardiopulmonary resuscitation with four different chest compression-ventilation ratios

Study objective: The optimal ratio of chest compressions to ventilations during cardiopulmonary resuscitation (CPR) is unknown. We determine 24-hour survival and neurologic outcome, comparing 4 different chest compression-ventilation CPR ratios in a porcine model of prolonged cardiac arrest and bystander CPR. Methods: Forty swine were instrumented and subjected to 3 minutes of ventricular fibrillation followed by 12 minutes of CPR by using 1 of 4 models of chest compression-ventilation ratios as follows: (1) standard CPR with a ratio of 15:2; (2) CC-CPR, chest compressions only with no ventilations for 12 minutes; (3) 50:5-CPR, CPR with a ratio of 50:5 compressions to ventilations, as advocated by authorities in Great Britain; and (4) 100:2-CPR, 4 minutes of chest compressions only followed by CPR with a ratio of 100:2 compressions to ventilations. CPR was followed by standard advanced cardiac life support, 1 hour of critical care, and 24 hours of observation, followed by a neurologic evaluation. Results: There were no statistically significant differences in 24-hour survival among the 4 groups (standard CPR, 7/10; CC-CPR, 7/10; 50:5-CPR, 8/10; 100:2-CPR, 9/10). There were significant differences in 24-hour neurologic function, as evaluated by using the swine cerebral performance category scale. The animals receiving 100:2-CPR had significantly better neurologic function at 24 hours than the standard CPR group with a 15:2 ratio (1.5 versus 2.5; P =.007). The 100:2-CPR group also had better neurologic function than the CC-CPR group, which received chest compressions with no ventilations (1.5 versus 2.3; P =.027). Coronary perfusion pressures, aortic pressures, and myocardial and kidney blood flows were not significantly different among the groups. Coronary perfusion pressure as an integrated area under the curve was significantly better in the CC-CPR group than in the standard CPR group (P =.04). Minute ventilation and PaO2 were significantly lower in the CC-CPR group. Conclusion: In this experimental model of bystander CPR, the group receiving compressions only for 4 minutes followed by a compression-ventilation ratio of 100:2 achieved better neurologic outcome than the group receiving standard CPR and CC-CPR. Consideration of alternative chest compression-ventilation ratios might be appropriate. [Ann Emerg Med. 2002;40:553-562.]

Vasopressor response in a porcine model of hypothermic cardiac arrest is improved with active compression-decompression cardiopulmonary resuscitation using the inspiratory impedance threshold valve.

During normothermic cardiac arrest, a combination of active compression-decompression (ACD) cardiopulmonary resuscitation (CPR) with the inspiratory threshold valve (ITV) significantly improves vital organ blood flow, but this technique has not been studied during hypothermic cardiac arrest. Accordingly, we evaluated the hemodynamic effects of ACD + ITV CPR before, and after, the administration of vasopressin in a porcine model of hypothermic cardiac arrest. Pigs were surface-cooled until their body core temperature was 26 degrees C. After 10 min of untreated ventricular fibrillation, 14 animals were randomly assigned to either ACD CPR with the ITV (n = 7) or to standard (STD) CPR (n = 7). After 8 min of CPR, all animals received 0.4 U/kg vasopressin IV, and CPR was maintained for an additional 10 min in each group; defibrillation was attempted after 28 min of cardiac arrest, including 18 min of CPR. Before the administration of vasopressin, mean +/- SEM common carotid blood flow was significantly higher in the ACD + ITV group compared with STD CPR (67 +/- 13 versus 26 +/- 5 mL/min, respectively; P < 0.025). After vasopressin was given at minute 8 during CPR, mean +/- SEM coronary perfusion pressure was significantly higher in the ACD + ITV group, but did not increase in the STD group (29 +/- 3 versus 15 +/- 2 mm Hg, and 25 +/- 1 versus 14 +/- 1 mm Hg at minute 12 and 18, respectively; P < 0.001); mean +/- SEM common carotid blood flow remained higher at respective time points (33 +/- 8 versus 10 +/- 3 mL/min, and 31 +/- 7 versus 7 +/- 3 mL/min, respectively; P < 0.01). Without active rewarming, spontaneous circulation was restored and maintained for 1 h in three of seven animals in the ACD + ITV group versus none of seven animals in the STD CPR group (not significant). During hypothermic cardiac arrest, ACD CPR with the ITV improved common carotid blood flow compared with STD CPR alone. Moreover, after the administration of vasopressin, coronary perfusion pressure was significantly higher during ACD + ITV CPR, but not during STD CPR. New strategies are needed to improve the efficiency of cardiopulmonary resuscitation (CPR) in hypothermic cardiac arrest. Active compression-decompression CPR with the inspiratory threshold valve improved carotid blood flow (and coronary perfusion pressure with vasopressin) compared with standard CPR.

Active compression-decompression cardiopulmonary resuscitation: a population-based, prospective randomised clinical trial in out-of-hospital cardiac arrest

Different mechanical devices have been developed to improve cardiopulmonary resuscitation (CPR). The aim of this study was to evaluate active compression-decompression (ACD) CPR applied by Emergency Medical Service (EMS) in a defined population. The Trondheim region EMS (population 154 000) employs simultaneous paramedic and physician response. Upon decision to treat, patients with cardiac arrest of presumed cardiac origin were allocated to ACD CPR (CardioPump®) or standard CPR by drawing a random number tag. Outcome in each patient was determined on a 5 point ordinal scale (no clinical improvement=1, survival to discharge=5). In 4 years, CPR was attempted in a total of 431 cardiac arrests, 54 patients (13%) survived to discharge; 302 patients with similar baseline characteristics were randomised. The prevalence of bystander CPR was 57% and the median call-arrival interval 9 min. By intention to treat, the mean score in the standard CPR group was 2.51 and 17/145 patients (12%) survived. The mean score in the ACD CPR group was 2.53 ( P=0.9) and 20/157 patients (13%) survived. Cerebral outcome was similar in the two groups. Among the 145 ACD patients, the technique was successfully applied in 110, found inapplicable in 35 and in seven patients chest compressions were unnecessary. This is the largest, single-centre, randomised, population based study of ACD CPR in out-of-hospital cardiac arrest to date. Even when considering a wider outcome spectrum than crude survival, we found no evidence of clinical benefit. In a quarter of cases ACD CPR was inapplicable, further limiting its potential usefulness.

A Randomized Clinical Trial of Active Compression-Decompression CPR vs Standard CPR in Out-of-Hospital Cardiac Arrest in Two Cities

Objective. —To compare the effectiveness of active compression-decompression (ACD) cardiopulmonary resuscitation (CPR) with a handheld suction device vs standard manual CPR in victims of out-of-hospital cardiopulmonary arrest. Design. —Prospective randomized clinical trial with crossover group design. Setting. —Emergency medical services (EMS) of a large (San Francisco) and medium-sized (Fresno) city in California. Patients. —All normothermic adult victims of out-of-hospital, nontraumatic cardiac arrest on whom CPR was performed by first responders. Intervention. —Patients were randomized to receive either standard manual CPR according to American Heart Association guidelines or ACD CPR, on first-responder contact. Main Outcome Measures. —Return of spontaneous circulation, admission to the intensive care unit, survival to hospital discharge, and neurological function at hospital discharge. Results. —The ACD group (n=117 in Fresno; n=297 in San Francisco) and standard group (n=136 in Fresno; n=310 in San Francisco) were similar with regard to demographic and prognostic variables, such as age, witnessed arrest and bystander CPR frequency, and initial cardiac rhythm. Average interval from 911 call activation to EMS responder arrival was 6.4 minutes in Fresno and 4.0 minutes in San Francisco. In Fresno, there was no difference between the ACD group and standard CPR group in return of spontaneous circulation (17% vs 20%; P =.68), hospital admission (16% vs 20%; P =.56), hospital discharge (5% vs 7%; P =.64), or cerebral performance category score at discharge (1.5 vs 1.6; P =.90). Similarly, in San Francisco there was no difference between the ACD group and standard CPR group in return of spontaneous circulation (19% vs 21%; P =.65), hospital admission (13.5% vs 14.5%; P =.79), hospital discharge (4.7% vs 5.5%; P =.80), or cerebral performance category score at discharge (2.2 vs 2.6; P =.31). There was no increase in significant complications associated with the use of ACD CPR. Conclusion. —There was no improvement in outcome with ACD CPR in out-of-hospital cardiac arrest in these two cities. Differences in study design, demographics, EMS systems, response intervals, training, and technique performance may contribute to the lack of improvement in initial resuscitation with ACD CPR compared with previous studies. Future research needs to control these variables to determine the reason for these differences in outcome. ( JAMA . 1995;273:1261-1268)