Papel de la hiperoxia en el ictus de territorio anterior

Abstract

Primary: - Determine the effect of supplemental oxygen in functional recovery of patients with ischemic stroke in the anterior cerebral circulation after intra-arterial mechanical thrombectomy (IAMT). - Construction of an adjusted regression model that allows us to establish a degree of recommendation in oxygen therapy for this group of patients. Secondary: analysis of other variables predictive of severity in the hyperoxia group: - Days of stay in the ICU. - NIHSS score obtained 24 hours after IAMT. MATERIAL AND METHODS STUDY DESIGN: prospective cohort study with follow-up without repeated measures. The study population included all patients consecutively admitted to the Intensive Care Unit (ICU) of the University Hospital Virgen de la Arrixaca, Murcia, by an ischemic stroke in the anterior cerebral circulation and following an IAMT, between April 2010 and December 2015. Oxygen was administered to ensure oxygen saturation>94%. Two groups were defined: paO2 less than or equal to 120 mmHg and paO2>120 mmHg (hyperoxia) The relationship between oxygenation of patients and the achievement of a poor functional outcome at 90 days after the TIAM was evaluated by a score obtained in the modified Rankin Scale of 4 or more points. STATISTICAL: The outcomes were presented as an OR between hyperoxia and mRS greater than or equal to4 at 90 days by logistic regression, adjusted and unadjusted, based on the confounding factors identified in the study. We obtained the most parsimonious model that did not modify the Odds Ratio by more than 10%. A univariate analysis established the association between hyperoxia and major NIHSS at 24 hours after IAMT and longer stay in ICU. RESULTS The poor functional outcome was significantly higher in the hyperoxia group OR 2.27 (95% CI, 1.22-4.23, p=0.01). Thus, hyperoxia was an independent factor of poor functional outcome, being 2.27 times more frequent among patients with mRS greater than or equal to4. Mortality of patients at 90 days was higher in the hyperoxia group, 28.6% vs 18.7%, p = 0.04. Patients who presented hyperoxia obtained an NIHSS significantly higher at 24 hours after IAMT, 15 vs 9.5, p<0.01; And, probably in relation to these findings, they needed a longer ICU stay, 3 days Vs 2 days, p=0.03. CONCLUSIONS - Increased oxygen levels in the blood of patients that have suffered ischemic stroke after IAMT are related to a worse functional outcome established by mRS of 4 scores or more and therefore, with a higher degree of dependency. Based on these results, it cannot be assured that hyperoxia will worsen the recovery of stroke patients, but it certainly constitutes an independent variable associated with poor functional recovery. - Until there is enough evidence to support the routine supplementary oxygen in all stroke patients, its use should be restricted to maintaining oxygen saturation within normal ranges. The purpose of this is to obtain a PaO2 level that ensures adequate tissue perfusion. It seems prudent to avoid the supplementation with high oxygen concentrations that might lead to a state of hyperoxia. - Patients with hyperoxia obtained a greater NIHSS score at 24 hours after TIAM and, consecutively, a longer ICU stay was required. - New clinical studies are necessary in order to assess more conservative strategies of oxygen therapy, especially in critical patients with conditions in which there is ischemia-reperfusion, like in the case of stroke.