Cerebral oximetry monitoring during sinus endoscopy

Objectives/Hypothesis Deliberate hypotension, reverse Trendelenburg position, and hyperventilation are techniques utilized during functional endoscopic sinus surgery to attempt to reduce surgical bleeding. These methods may predispose patients to cerebral ischemia. Cerebral oximetry has not been investigated extensively within otolaryngologic surgery. Our study sought to address the question of whether cerebral oximetry is feasible in the FESS population and evaluate whether the data provided may be useful in the assessment of cerebral perfusion. Study Design Prospective, blinded, observational trial. Methods We designed a prospective, blinded, observational trial of patients undergoing functional endoscopic sinus surgery using cerebral oximetry monitoring. Collected data included mean arterial blood pressure (MAP), end-tidal carbon dioxide (EtCO₂), cerebral saturation (SctO₂), postanesthesia care unit (PACU) length of stay, and incidence of postoperative nausea and vomiting (PONV). Results Thirty-one subjects were enrolled into the study. Univariate analyses showed cross-correlation between concurrent EtCO₂ values and SctO₂ of 0.43 (95% CI: 0.27 to 0.59) and between present EtCO₂ and the SctO₂ 5 minutes later of 0.46 (95% CI: 0.33 to 0.59). MAP was not significantly cross-correlated with SctO₂. Patients who had an SctO₂ below 60% at any time had a median (interquartile range [IQR]) PACU length of stay of 167 (IQR, 95-386) minutes. Patients whose cerebral saturation did not fall below 60% at any time had a median PACU length of stay of 103 (IQR, 76-155) minutes. This difference did not reach statistical significance (P = .257). The median (IQR) maximum decline in SctO₂ for patients with PONV was 11.2% (IQR, 8.2%-13.1%) and for patients without PONV was 7.1% (IQR, 5.1%-9.8%) (P = .126). Conclusions Cerebral oximetry monitoring was feasible during functional endoscopic sinus surgery. This study demonstrated a cross-correlation between EtCO₂ and SctO₂, but not MAP and SctO₂. A longer PACU length of stay and higher rate of PONV were seen but did not reach statistical significance.