Short-term hemodynamic variability in supine and tilted position in young women

The aim of the study was to evaluate short-term changes in hemodynamic parameters observed in supine and tilted positions. Six young women (age: 21-25) participated in the study. The cardiac inter-beat interval (RR), stroke volume (SV), ejection time (ET) and pre-ejection period (PEP) parameters were followed over two six-minute periods, in supine position and 10 minutes after a 60-degree head-up tilting manoeuvre, using continuously recorded impedance cardiography (ICG) and electrocardiography (ECG) signals. Hemodynamic variability was evaluated using standard deviation (SD), coefficient of variation (CV) and quartile deviation (QD). For the supine position, the mean (M), SD, CV and QD of the observed parameters were as follows. SV: 66 ml, 11 ml, 17.5 %, 16 ml. RR: 878 ms, 100 ms, 11.2 %, 111 ms. ET: 292 ms, 32 ms, 11.4 %, 47 ms. PEP: 115 ms, 15 ms, 13.4 %, 19 ms. In the tilted position, the following were observed. SV: 53 ml, 10 ml, 19.8 %, 12.5 ml. RR: 736 ms, 88 ms, 11.8 %, 74 ms. ET: 252 ms, 30 ms, 11.7 %, 23 ms. PEP: 134 ms, 12 ms, 9 %, 13 ms. The changes in hemodynamic variability caused by tilting are not unidirectional.