The use of a vascular occlusion test combined with near-infrared spectroscopy in perioperative care: a systematic review.

In the perioperative phase oxygen delivery and consumption can be influenced by different factors, i.e. type of surgery, anesthetic and cardiovascular drugs, or fluids. By combining near-infrared spectroscopy (NIRS) monitoring of regional tissue oxygen saturation (StO2) with an ischemic provocation test, the vascular occlusion test (VOT), local tissue oxygen consumption and vascular reactivity at the microcirculatory level can be assessed. This systematic review aims to give an overview of the clinical information that VOT-derived NIRS values can provide in the perioperative period. After performing a systematic literature search, we included 29 articles. It was not possible to perform a meta-analysis because of the lack of comparable data and the observational nature of the majority of the included articles. We have clustered the found articles in two groups: non-cardiac surgery and cardiac surgery. We found that VOT-derived NIRS values show a wide variability and are influenced by the effects of anesthetics, cardiovascular drugs, fluids, and by the type of surgery. Additionally, deviations in VOT-derived NIRS values are also associated with adverse patients' outcomes, such as postoperative complications, prolonged mechanical ventilation and prolonged hospital length of stay. However, given the variability in VOT-derived NIRS values, clinical applicability remains elusive. Future clinical interventional trials might provide additional insight into the potential of VOT associated with NIRS to optimize perioperative care by targeting specific interventions to optimize the function of the microvasculature.

Amplitude-Integrated EEG and Cerebral Near-Infrared Spectroscopy in Cooled, Asphyxiated Infants.

OBJECTIVE: To assess the predictive value of amplitude-integrated electroencephalography EEG (aEEG) and near-infrared spectroscopy (NIRS) during therapeutic hypothermia. PATIENTS AND METHODS: We studied 39 cooled, asphyxiated infants. We assessed aEEG and calculated mean regional cerebral oxygen saturation (rcSO2) during and after treatment. At 30 months, we performed a neurological examination and administered the Bayley Scales of Infant and Toddler Development, 3rd edition. We calculated the odds ratios (ORs) of abnormal aEEG and rcSO2 for severely abnormal outcome. RESULTS: At 6 and 12 hours, severely abnormal aEEGs predicted severely abnormal outcomes (OR, 7.7 [95% confidence interval, CI, 1.39-42.6] and 24.4 [95% CI 4.2-143] respectively), as did epileptic activity (OR 28.9, 4.6-183). During the first 48 hours, rcSO2 was not associated with outcome, but at 72 hours after birth and after rewarming it was, with ORs for severely abnormal outcomes of 12.8 (1.31-124) and 21.6 (1.05-189), respectively. In multivariate analyses, aEEG and rcSO2 remained independently predictive in the model at 48 hours and significantly from 72 hours after birth onward. CONCLUSION: aEEG was a strong predictor of adverse outcome. After 48 hours of cooling, a higher rcSO2 was associated with a severely abnormal outcome, adding to the predictive value of aEEG in cooled, asphyxiated infants.