Effects of changes in end-tidal carbon dioxide tension on oral tissue blood flow and tissue oxygen tension during remifentanil infusion in rabbits

Abstract

Purpose: The aim of this study was to investigate the effects of end-tidal carbon dioxide tension (ETCO₂) changes during remifentanil infusion on 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 rabbits.

Methods: Ten male tracheotomized Japan White rabbits were anesthetized and ventilated with sevoflurane. ETCO₂ was adjusted to 30 mmHg. After baseline measurement, CO₂ was added to the inhaled air, and ETCO₂ was increased to 40 and 60 mmHg. Heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), BBF, MBF, PbO₂, and PmO₂ were recorded with and without remifentanil infusion at 0.4 µg/kg/min.

Results: Two-way repeated measures analysis of variance showed no interaction between ETCO₂ and remifentanil in all variables. Remifentanil infusion produced decreases in HR, SBP, MAP, BBF and MBF compared with those without remifentanil infusion, while it did not affect DBP, PbO₂ and PmO₂. Elevation of ETCO₂ from 30 to 60 mmHg produced decreases in HR and MBF, and increases in SBP, DBP, MAP and BBF, while it did not affect PbO₂ and PmO₂.

Conclusion: PbO₂ and PmO₂ remained unchanged despite changes in BBF and MBF during ETCO₂ change with or without remifentanil infusion.

Keywords: End-tidal carbon dioxide tension; Remifentanil; Tissue oxygen tension.