Changes in left ventricular ejection time and pulse transit time derived from finger photoplethysmogram and electrocardiogram during moderate haemorrhage

Abstract

Shortening of LVET(p) from 303+/-2 to 293+/-3 ms (mean+/-SEM; P<0.01) and prolongation of PTT from 177+/-3 to 186+/-4 ms (P<0.01) were observed in 81% and 91% of subjects respectively when comparing PRE and POST. During blood donation, progressive blood loss produced falling trends in LVET(p) (P<0.01) and rising trends in PTT (P<0.01) in FIRST and SECOND, but a falling trend in RRi (P<0.01) was only observed in SECOND. Monitoring trends in timing variables derived from non-invasive ECG and finger PPG signals may facilitate detection of blood loss in the early phase.