BackgroundAccording to the guidelines for cardiopulmonary resuscitation (CPR), the rotation time for chest compression should be about 2 min. The quality of chest compressions is related to the physical fitness of the rescuer, but this was not considered when determining rotation time. The present study aimed to clarify associations between body weight and the quality of chest compression and physical fatigue during CPR performed by 18 registered nurses (10 male and 8 female) assigned to light and heavy groups according to the average weight for each sex in Japan.MethodsFive-minute chest compressions were then performed on a manikin that was placed on the floor. Measurement parameters were compression depth, heart rate, oxygen uptake, integrated electromyography signals, and rating of perceived exertion. Compression depth was evaluated according to the ratio (%) of adequate compressions (at least 5 cm deep).ResultsThe ratio of adequate compressions decreased significantly over time in the light group. Values for heart rate, oxygen uptake, muscle activity defined as integrated electromyography signals, and rating of perceived exertion were significantly higher for the light group than for the heavy group.ConclusionChest compression caused increased fatigue among the light group, which consequently resulted in a gradual fall in the quality of chest compression. These results suggested that individuals with a lower body weight should rotate at 1-min intervals to maintain high quality CPR and thus improve the survival rates and neurological outcomes of victims of cardiac arrest.

The aim of this study was to investigate the impact of caregiver knowledge and experience on muscle activity and perceived exertion while repositioning bedridden patients. Subjects were 40-to 65-year-old female caregivers divided into novice and experienced groups. Subjects from both groups performed home-care repositioning techniques on bedridden patients while muscle activity was recorded via electromyogram. Recordings were made from four muscles on the subjects' dominant side: the latissimus dorsi, the biceps brachii, the erector spinae, and the rectus femoris. The subjective burden involved in repositioning was also assessed using the rate of perceived exertion (RPE) and visual analog scales (VAS). Rectus femoris percentage of maximum voluntary contraction (%MVC) values were significantly lower than latissimus dorsi, erector spinae, and biceps brachii values in the novice group. %MVC values from the latissimus dorsi and biceps brachii were significantly higher among the novice group compared to the experienced group. RPE ratings from the novice group were significantly higher than those of the experienced group, and there was a non-significant trend for higher VAS values for the low back, arms, and legs in the novice group compared to the experienced group. Novice caregivers tended to change the patient's position by pulling with the upper limbs without using the lower limbs. In contrast, experienced caregivers exerted less energy by communicating with the patient and utilizing the patient's own movements. They used large, distributed muscle groups that effectively harnessed body mechanics and prevented excess exertion.