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Changes in left ventricular ejection time and pulse transit time derived from finger photoplethysmogram and electrocardiogram during moderate haemorrhage
Author(s) -
Middleton Paul M.,
Chan Gregory S.H.,
O’Lone Emma,
Steel Elizabeth,
Carroll Rebecca,
Celler Branko G.,
Lovell Nigel H.
Publication year - 2009
Publication title -
clinical physiology and functional imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.608
H-Index - 67
eISSN - 1475-097X
pISSN - 1475-0961
DOI - 10.1111/j.1475-097x.2008.00843.x
Subject(s) - medicine , photoplethysmogram , cardiology , blood volume , blood donor , filter (signal processing) , computer science , immunology , computer vision
Summary Objectives: Early identification of haemorrhage is difficult when a bleeding site is not apparent. This study explored the potential use of the finger photoplethysmographic (PPG) waveform derived left ventricular ejection time (LVET p ) and pulse transit time (PTT) for detecting blood loss, by using blood donation as a model of controlled mild to moderate haemorrhage. Methods: This was a prospective, observational study carried out in a convenience sample of blood donors. LVET p , PTT and R‐R interval (RRi) were computed from simultaneous measurement of the electrocardiogram (ECG) and the finger infrared photoplethysmogram obtained from 43 healthy volunteers during blood donation. The blood donation process was divided into four stages: (i) Pre‐donation (PRE), (ii) first half of donation (FIRST), (iii) second half of donation (SECOND), (iv) post‐donation (POST). Results and conclusions: 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.