Article

CPREzy: an evaluation during simulated cardiac arrest on a hospital bed.

Division of Medical Sciences, University of Birmingham, Birmingham B152TT, UK.
Resuscitation (Impact Factor: 3.96). 01/2005; 64(1):103-8. DOI: 10.1016/j.resuscitation.2004.08.011
Source: PubMed

ABSTRACT CPREzy is a new adjunct designed to improve the application of manual external chest compressions (ECC) during cardiopulmonary resuscitation (CPR). The aim of this study was to determine the effect of using the CPREzy device compared to standard CPR during the simulated resuscitation of a patient on a hospital bed. Twenty medical student volunteers were randomised using a cross over trial design to perform 3 min of continuous ECC using CPREzy and standard CPR. There was a significant improvement in ECC depth with CPREzy compared to standard CPR 42.9 (4.4) mm versus 34.2 (7.6): mm, P = 0.001; 95% CI d.f. 4.4-12.9 mm. This translated to a reduction in the percentage of shallow compressions (<38 mm) with CPREzy 16 (23)% compared to standard CPR 59 (44)%, P = 0.003. There was a small increase in the percentage of compression regarded excessive (>51 mm): CPREzy 6.5 (19)% versus standard CPR 0 (0.1)%. P = 0.012). There was no difference in compression rate or duty cycle between techniques. Equal numbers of participants (40% in each group) performed one of more incorrectly placed chest compression. However the total number of incorrect compressions was higher for the CPREzy group (26% versus 3.9% standard CPR, P < 0.001). This was due to a higher number of low compressions (26% of total compressions for CPREzy versus 1% for standard CPR, P < 0.001). In conclusion, CPREzy was associated with significant improvements in ECC performance. Further animal and clinical studies are required to validate this finding in vivo and to see if it translates to an improvement in outcome in human victims of cardiac arrest.

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The tested feedback device (prototype by Laerdal, Stavanger, Norway) measures 152mm×64mm×28mm and is designed to be placed between the patient’s chest and rescuer´s palm. A 26mm×26mm colour display provides feedback information. The study was performed in a randomized crossover design. The experimental setup consisted of a training mannequin (Resusci® Anne, Laerdal, Stavanger, Norway) connected to a laptop. For data acquisition, the appropriate software (Laerdal PC Skill Reporting Systems Version 1.3.0) was used. At a two-sided level of significance of 5% and a power of 80%, a calculation based on former studies resulted in a sample size of 96 subjects. This calculation included a dropout rate of 10%. After a random assignment to one of two groups each subject passed twice through the testing assembly. For each test a standardized sequence including two minutes of continuous chest compressions was implemented. Group A was first tested applying continuous chest compressions using the device and then without it. Group B underwent the same testing, but in reverse order. Between the two tests there was a compulsory minimum break of 45 minutes. The statistical analysis of the crossover data was based on a modified logistic regression model for binary categorized endpoints and on a modified variance model for continuous endpoints. A carryover effect from the first to the second test had to be ruled out to ensure the quality of study design and statistical approach. Out of 94 potential subjects, 93 were finally included in the study. Only one subject was excluded because of impaired physical condition. In the end the sample was composed of 34 A&E practicioners, 14 EMTs and 45 paramedics. When the feedback device was used, all primary endpoints improved significantly. Furthermore, the 95%-confidence interval (95%-CI) could be found in a confined range for both criteria. Correct mean compression depth was achieved by 45.2% (95%-CI: 30.5–64.9mm) of subjects without vs. 73.1% (95%-CI: 40.3–57.4mm) with device (p < 0.001). Correct average compression rate could be observed in 62.4% (95%-CI: 80.1–147.8 min-1) without vs. 94.6% (95%-CI: 87.3–126.6 min-1) with device (p < 0.001). Applying all necessary criteria to each individual resuscitation effort, all those subjects were detected which had met the requirements of 80% accurate compressions and a rate of 90 to 120 compressions per minute. With feedback, 51.6% of the subjects comply with these criteria whereas without feedback, only 18.3% of the subjects performed a sufficient cardiac massage (p<0.001). Overall, 85% of the subjects thought the feedback system was helpful and 80.6% would use it if available.