Evaluation of pre-operative anxiety and propofol-induced sedation using newly proposed indices of finger vascular tone

Abstract: This study examined estimates of finger vascular tone, obtained from photoplethysmography. Normalized and double‐normalized pulse volume (NPV and DNPV), blood volume (BV), and pulse volume (PV) were obtained in 2 male and 7 female middle‐aged patients at an outpatient office 1–3 days before an operation and in the operating room before and after anesthesia by propofol. There was a preoperative decrease in NPV, and the propofol injection yielded a moderate increase in BV. The latter seemed to contribute to a decrease in DNPV. A partial correlation controlling for body mass index was observed between the change in NPV and the dose of propofol; a larger reduction in NPV before anesthesia compared with the control condition was accompanied by the need for a greater infusion of propofol for sedation. In conclusion, among the measures examined, NPV appears to be the best indicator of heightened arteriolar vascular tone.