Journal of clinical monitoring and computing
-
J Clin Monit Comput · Oct 2007
Impact of withdrawal of 450 ml of blood on respiration-induced oscillations of the ear plethysmographic waveform.
It has been widely appreciated that ventilation-induced variations in systolic blood pressure during mechanical ventilation correlate with changes in intravascular volume. The present study assessed whether alterations in volume status likewise can be detected with noninvasive monitoring (ear plethysmograph) in non-intubated subjects (awake volunteers). ⋯ Respiration-induced changes of the ear plethysmographic waveform during spontaneous ventilation increase significantly as a consequence of withdrawal of approximately one unit of blood in healthy volunteers.