Effects of adrenaline on rhythm transitions in out-of-hospital cardiac arrest.

BACKGROUND: We wanted to study the effects of intravenous (i.v.) adrenaline (epinephrine) on rhythm transitions during cardiac arrest with initial or secondary ventricular fibrillation/tachycardia (VF/VT). METHODS: Post hoc analysis of patients included in a randomised controlled trial of i.v. drugs in adult, non-traumatic out-of-hospital cardiac arrest patients who were defibrillated and had a readable electrocardiography recording. Patients who received adrenaline were compared with patients who did not. Cardiac rhythms were annotated manually using the defibrillator data. RESULTS: Eight hundred and forty-nine patients were included in the randomised trial of which 223 were included in this analysis; 119 in the adrenaline group and 104 in the no-adrenaline group. The proportion of patients with one or more VF/VT episodes after temporary return of spontaneous circulation (ROSC) was higher in the adrenaline than in the no-adrenaline group, 24% vs. 12%, P = 0.03. Most relapses from ROSC to VF/VT in the no-adrenaline group occurred during the first 20 min of resuscitation, whereas patients in the adrenaline group experienced such relapses even after 20 min. Fibrillations from asystole or pulseless electrical activity, shock resistant VF/VT and the number of rhythm transitions per patient was higher in the adrenalin group compared with the no-adrenalin group: 90% vs. 69%, P < 0.001; 46% vs. 33%, P = 0.006; median 8 (5,13) vs. 2 (1,5), P < 0.001, respectively. CONCLUSION: Patients who received adrenaline had more rhythm transitions from ROSC and non-shockable rhythms to VF/VT.

Haemodynamic outcomes during piston-based mechanical CPR with or without active decompression in a porcine model of cardiac arrest.

BACKGROUND: Experimental active compression-decompression (ACD) CPR is associated with increased haemodynamic outcomes compared to standard mechanical chest compressions. Since no clinically available mechanical chest compression device is capable of ACD-CPR, we modified the LUCAS 2 (Physio-Control, Lund, Sweden) to deliver ACD-CPR, hypothesising it would improve haemodynamic outcomes compared with standard LUCAS CPR on pigs with cardiac arrest. METHODS: The modified LUCAS delivering 5 cm compressions with or without 2 cm active decompression above anatomical chest level was studied in a randomized crossover design on 19 Norwegian domestic pigs. VF was electrically induced and untreated for 2 min. Each pig received ACD-CPR and standard mechanical CPR in three 180-s. phases. We measured aortic, right atrial, coronary perfusion, intracranial and oesophageal pressure, cerebral and carotid blood flow and cardiac output. Two-sided paired samples t-test was used for continuous parametric data and Wilcoxon test for non-parametric data. P < 0.05 was considered significant. RESULTS: Due to injuries/device failure, the experimental protocol was completed in nine of 19 pigs. Cardiac output (l/min, median, (25, 75-percentiles): 1.5 (1.1, 1.7) vs. 1.1 (0.8, 1.5), p < 0.01), cerebral blood flow (AU, 297 vs. 253, mean difference: 44, 95% CI; 14-74, p = 0.01), and carotid blood flow (l/min, median, (25, 75-percentiles): 97 (70, 106) vs. 83 (57, 94), p < 0.01) were higher during ACD-CPR compared to standard mechanical CPR. Coronary perfusion pressure (CPP) trended towards higher in end decompression phase. CONCLUSION: Cardiac output and brain blood flow improved with mechanical ACD-CPR and CPP trended towards higher during end-diastole compared to standard LUCAS CPR.

Quality of CPR performed by trained bystanders with optimized pre-arrival instructions.

OBJECTIVE: Telephone-CPR (T-CPR) can increase initiation of bystander CPR. We wanted to study if quality oriented continuous T-CPR would improve CPR performance vs. standard T-CPR. METHOD: Ninety-five trained rescuers aged 22-69 were randomized to standard T-CPR or experimental continuous T-CPR (comprises continuous instructions, questions and encouragement). They were instructed to perform 10 min of chest compressions-only on a manikin, which recorded CPR performance in a small, confined kitchen. Three video-cameras captured algorithm time data, CPR technique and communication. Demography and training experience were captured during debriefing. RESULTS: Participants receiving continuous T-CPR delivered significantly more chest compressions (median 1000 vs. 870 compressions, p=0.014) and compressed more frequently to a compression rate between 90 and 120 min(-1) (median 87% vs. 60% of compressions, p<0.001), compared to those receiving standard T-CPR. This also resulted in less time without compressions after CPR had started (median 12s vs. 64 s, p<0.001), but longer time interval from initiating contact with dispatcher to first chest compression (median 144 s vs. 84 s, p<0.001). There was no difference in chest compression depth (mean 47 mm vs. 48 mm, p = 0.90) or in demography, education and previous CPR training between the groups. CONCLUSION: In our simulated scenario with CPR trained lay rescuers, experimental continuous T-CPR gave better chest compression rate and less hands-off time during CPR, but resulted in delayed time to first chest compression compared to standard T-CPR instructions.

Video analysis of dispatcher-rescuer teamwork-Effects on CPR technique and performance.

OBJECTIVE: We wanted to study the effect of continuous dispatcher communication on CPR technique and performance during 10min of simulated cardiac arrest. METHOD: We reviewed video recordings and manikin data from 30 CPR trained lay people who where left alone in a simulated cardiac arrest situation with a manikin in a home-like environment (in a small, confined kitchen with the disturbing noise of a radio). CPR was performed for 10min with continuous telephone instructions via speaker function from a dispatcher. The dispatcher was blinded for CPR performance and video. Dispatcher communication, compression technique and ventilation technique was scored as accomplished or failed in the 1st and 10th minute. RESULTS: 29/30 rescuers were able to hear instructions, answer questions from the dispatcher and perform CPR in parallel. Rescuer position beside manikin was initially correct for 13/30, improving to 21/30 (p=0.008). Compression technique was adequate for the whole episode, with an insignificant trend for improvement; 29 to 30/30 using straight arms, 28 to 30/30 in a vertical position over chest and 24 to 27/30 counting loudly. 17/29 placed their hands between the nipples initially, improving to 24/29 (p=0.065). Mean compression rate improved from 84 to 101min(-1) (p<0.001), and compression depth maintained adequate (43 to 42mm). Initially, 17/29 used chin-lift manoeuvre, 14/30 used head-tilt and 19/29 used nose pinch to manage open airways, compared to 18, 20 and 22/29 (ns) in the 10th minute, respectively. Successful delivery of ventilation improved from 13/30 to 23/30 (p=0.006). CONCLUSION: Bystander and dispatcher can communicate successfully during ongoing CPR using a telephone with speaker function. CPR technique and quality improved or did not change over 10min with continuous dispatcher assistance. These results suggest a potential for improved bystander CPR using rescuer-dispatcher teamwork.

A randomized trial of the capability of elderly lay persons to perform chest compression only CPR versus standard 30:2 CPR.

AIM OF THE STUDY: Early cardiopulmonary resuscitation (CPR) improves survival after cardiac arrest, but there is a discrepancy between the age group normally attending CPR-classes and the age group most likely to witness a cardiac arrest. We wanted to study if elderly lay persons could perform 10min of CPR on a realistic manikin with continuous chest compressions (CCC) and conventional CPR (30:2). METHODS: Volunteers were tested 5-7 months after CPR-classes. They were randomized to CCC or 30:2, and to receive feedback (FB) or not. Quality of CPR, age adjusted maximum heart rate (HRmax), and subjective exhaustion ratings were measured and evaluated in a blinded fashion. Temporal development and group differences were evaluated with ANOVA procedures. RESULTS: All 64 volunteers were able to perform CPR for 10min and rated their efforts as mild to moderate in concordance with a mean HRmax of 78%. Quality of CPR was similar in all groups, except for chest compression rate that was slightly higher and had less variability in the FB group. Overall chest compression depth was 41+/-4.5mm. Analysis of temporal development of chest compression depth revealed a small initial decline before leveling off. As expected, CCC group had less pauses and higher total number of chests compressions. CONCLUSION: Lay people in the age group 50-76 were able to perform CPR with acceptable quality for 10min and we found only very slight temporal quality deterioration. This makes training programs for the elderly meaningful to improve survival after cardiac arrest.