Physiological responses in female rescuers during 30 minutes sustained CPR with feedback: a comparison between medicine and physical education students.

OBJECTIVES: Since fatigue seems related to poorer physical fitness rather than to gender, we analyzed the physiological responses in female medicine and physical education students during a 30 minutes sustained cardiopulmonary resuscitation (CPR) sequence.

METHODS: Handgrip strength and maximal aerobic power (V02 max) determined strength and endurance. Twenty-three medicine (M) and 27 physical education (PE) female students performed 30 minutes CPR. Compression quality and ECG were continuously monitored, heart rate and non-invasive blood pressure (NIBP) every 2 minutes. Capillary pH, PcCO2, lactate, potassium and sodium bicarbonate were analyzed every 10 minutes.

RESULTS: Handgrip strength (PE 37 kg vs. M 35 kg; p<0.05) and V02 max (PE 50 ml/kg/min vs. M 44 ml/ kg/min; p<0.05) revealed a better strength and endurance in PE students. Six medicine and 1 PE student did not complete the entire 30 minutes of CPR. Percentage compressions >5 cm was comparable in both groups (PE 80%; M 79%; p=0.67). Mean heart rate during CPR was higher in the M group (148 bpm) compared to the PE group (132 bpm; p<0.05). No intergroup differences in NIBP, pH, PcCO2, potassium and sodium bicarbonate were observed. Mean lactate during CPR was higher in the M group: 3.5 mmol/l (SD 1.4) compared to the PE group: 2.5 mmol/I (SD 0.7) (p<0.05).

CONCLUSION: A high quality sustained CPR effort was well tolerated by all female rescuers. Poorer physical condition (M group) resulted in more drop out after 10 and 20 minutes and in a higher heart rate and blood lactate over time. Improving physical condition may result in less physiological strain and lower perceived exertion.