Decreases in oral tissue blood flow induced by remifentanil is not accompanied by deterioration of oral tissue oxygen tension in rabbits

Publication date: Available online 3 January 2019

Source: Journal of Oral and Maxillofacial Surgery

Author(s): Sayaka Kobayashi, Masataka Kasahara, Yui Akiike, Nobuyuki Matsuura, Tatsuya Ichinohe

Abstract

Purpose

The purpose of this study was to investigate the effects of remifentanil infusion on tissue blood flow and tissue oxygen tension in the mandibular bone marrow and the masseter muscle in rabbits. In addition, the changes in tissue oxygen consumption in those tissues during remifentanil infusion was investigated.

Material and Methods

Sixteen male tracheotomized Japan White rabbits are anesthetized with sevoflurane under mechanical ventilation. Under oxygen-air inhalation, fraction of inspiratory oxygen (F_IO₂) was set at 0.4 and remifentanil was infused at a rate of 0.4 μg•kg^-1•min^-1. Measurements were performed before remifentanil infusion, 20 minutes after the start of remifentanil infusion, 20 minutes and 60 minutes after the completion of remifentanil infusion (n=8). The observed variables included heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), mandibular bone marrow tissue blood flow (BBF), masseter muscle tissue blood flow (MBF), mandibular bone marrow tissue oxygen tension (PbO₂), and masseter muscle tissue oxygen tension (PmO₂). In another 8 rabbits, we observed arterial pH (pH), lactate, base excess (BE) and tissue oxygen consumption in the region from which the retromandibular vein received venous blood. Measurements were performed before remifentanil infusion and 20 minutes after the start of remifentanil infusion.

Results

HR, SBP, DBP, MAP, BBF, and MBF decreased during remifentanil infusion. PbO₂ increased 20 minutes after remifentanil infusion and returned to almost the baseline value 60 minutes after remifentanil infusion. PmO₂ did not change throughout the experiment. AV-Co₂ difference decreased during remifentanil infusion. Arterial pH, lactate and BE did not change during remifentanil infusion.

Conclusion

Remifentanil reduced tissue blood flow in the mandibular bone marrow and the masseter muscle while oxygen tension in those tissues did not decrease. It is suggested that tissue oxygen consumption decreased during remifentanil infusion.

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