External chest compressions using a mechanical feedback device : cross-over simulation study

External chest compressions (ECC) are essential components of resuscitation and are usually performed without any adjuncts in professional healthcare. Even for healthcare professionals during in-hospital and out-of-hospital resuscitation poor performance in ECC has been reported in recent years. Although several stand-alone devices have been developed none has been implemented as a standard in patient care. The aim of this study was to examine if the use of a mechanical device providing visual feedback and audible assistance during ECC improves performance of healthcare professionals following minimal and simplified instructions.

In a prospective, randomized cross-over study 81 healthcare professionals performed ECC for 3 min (in the assumed setting of a secured airway) twice on a manikin (Skillreporter ResusciAnne®, with PC-Skillreporting System Version 1.3.0, Laerdal, Stavanger, Norway) in a mock cardiac arrest scenario. Group 1 (n=40) performed ECC with the device first followed by classic ECC and group 2 (n=41) in the opposite order. Minimal instructions were standardized and provided by video instruction (1 min 38 s). Endpoints were achievement of a mean compression rate between 90 and 110/min and a mean compression depth of 40-50 mm. In addition participants had to answer questionnaires about demographic data, professional experience and recent recommendations for ECC as well as their impression of the device concerning the ease of use and their personal level of confidence. Data were analyzed for group-related and inter-group differences using SAS (Version 9.1.3, SAS Institute, Cary, NC).

A total of 81 healthcare professionals regularly involved in resuscitation attempts in pre-hospital or in-hospital settings took part in the study with no differences between the groups: females 35.8% (n=52), emergency medical technicians 32.1% (n=26), anesthesia nurses 32.1% (n=26), physicians (anesthesiology) 45% (n=29). In group 1 33 out of 40 (82.5%; 99.7±4.82/min; 95% confidence interval 95% CI: 98.1-101.2/min) reached the correct range for compression rate and 29/40 (72.5%; 44.0±4.95 mm; 95% CI: 42.4-45.6 mm) the correct compression depth using the assisting device. Afterwards they conducted classic ECC without the device and deteriorated significantly: correct compression rate was achieved by 12/40 (30%, p≤0.0001; 110.6±11.0/min (95% CI: 107.1-114.1/min), while 25/40 (62.5%; 44.5±5.63 mm; 95% CI: 42.6-46.3 mm) met the correct compression depth. Group 2 performed poorer in ECC without assistance and 5/41 (12.2%; 104.5±21.35/min; 95% CI: 97.8-111.3/min) reached the correct rate whereas 21/41 (51.2%; 39.6±7.61 mm; 95% CI: 37.2-42.0 mm) compressed to the appropriate depth. Using the device there was a significant improvement in the second evaluation with 34/41 (82.9%, p≤0.0001; 101.7±4.68/min; 95% CI: 100.2-103.2/min) reaching the correct rate and 36/41 (87.8%, p≤0.0001; 43.9±4.16 mm; 95% CI: 42.6-45.2 mm) the correct depth.

The tested device is easy to use after instruction of less than 3 min and improves ECC performance of healthcare professionals in simulated cardiac arrest with respect to compression depth as well as compression rate.