Early recognition of ischaemia with continuous real-time tissue oxygen monitoring in head and neck microvascular flaps

Abstract

Aim of this study was to evaluate the reliability of a continuous real-time tissue oxygen monitoring method (Licox®) for postoperative follow-up of free microvascular flaps after ablative head and neck tumour surgery. We also wanted to establish and test accurate alarm levels for this monitoring method. One hundred eighteen head and neck cancer patients, operated in Tampere University Hospital, Finland, were analysed. Tissue oxygen (PtiO2) levels were continuously monitored with the Licox® system. Receiver operating characteristic analysis was performed considering following alarming signals: a clear change in the trend of the curve leading to a decline more than 50% in 1 h or a decline below 10 mmHg in the PtiO2 level. Licox® recognized all the patients who needed re-operation with sensitivity of 100% and specificity of 88%. The overall success rate was 99.2% (117 of 118) and flap salvage rate 88% (seven of eight), respectively. The Licox® tissue oxygen pressure monitoring system is a reliable method for detecting early postoperative circulation problems in free microvascular flaps. The suggested alarm signals are a clear change in the trend of the curve leading a decline more than 50% in an hour or a decline below 10 mmHg.