Monitoring cerebral ischemia during cerebrovascular surgery

Evaluation of multimodal intraoperative neurophysiologic monitoring during supratentorial aneurysm surgery: a comparative study

The objective of this study is to determine the role of multimodal intraoperative neurophysiologic monitoring (IONM) in the overall outcome of intracranial aneurysms surgery, and the risk factors associated with ischemic complications. We grouped 268 ruptured and unruptured intracranial aneurysms surgically treated at our institution into 2 cohorts, based on the use of IONM (180; 67.16%) or non-use of IONM (88; 32.84%). The IONM technique used was multimodal: electroencephalogram (EEG), somatosensory evoked potentials (SSEPs), transcranial (TES), and direct cortical (DCS) stimulation motor evoked potentials (MEPs). There was a significant difference, with a reduction in perioperative strokes (p = 0.011) and better motor surgery-related outcome in the IONM group (p = 0.016). Independent risk factors identified for surgery ischemic complications were temporary clipping time ≥ 6'05″ (odds ratio [OR]: 3.03; 95% CI: 1.068-8.601; p = 0.037), aneurysm size ≥ 7.5 mm (OR: 2.65; 95% CI: 1.127-6.235; p = 0.026), and non-use of IONM (OR: 2.79; 95% CI: 1.171-6.636; p = 0.021). Conversely, aneurysm rupture was not detected as an independent risk factor (OR: 2.5; 95% CI: 0.55-4.55; p = 0.4). Longer temporary clipping time, larger aneurysm size, and the non-use of IONM could be considered as risk factors for ischemic complications during microsurgical clipping. A standardized designed protocol including multimodal IONM with DCS provides continuous information about blood supply and allows reduction of treatment-related morbidity. Multimodal IONM is a valuable technique in intracranial aneurysm surgery.

Association between Cerebral Oxygen Saturation with Outcome in Cardiac Surgery: Brain as an Index Organ

While both baseline regional cerebral oxygen saturation (rSO₂) and intraoperative rSO₂ decreases have prognostic importance in cardiac surgery, evidence is limited in patients who received interventions to correct rSO₂ decreases. The primary aim was to examine the association between rSO₂ values (both baseline rSO₂ and intraoperative decrease in rSO₂) with the composite of morbidity endpoints. We retrospectively analyzed 356 cardiac surgical patients having continuously recorded data of intraoperative rSO₂ values. Per institutional guidelines, patients received interventions to restore the rSO₂ value to ≥80% of the baseline value. Analyzed rSO₂ variables included baseline value, and area under the threshold below an absolute value of 50% (AUT50). Their association with outcome was analyzed with multivariable logistic regression. AUT50 (odds ratio, 1.05; 95% confidence interval; 1.01–1.08; p = 0.015) was shown to be an independent risk factor (along with age, chronic kidney disease, and cardiopulmonary bypass time) of adverse outcomes. In cardiac surgical patients who received interventions to correct decreases in rSO₂, increased severity of intraoperative decrease in rSO₂ as reflected by AUT below an absolute value of 50% was associated with a composite of adverse outcomes, implicating the importance of cerebral oximetry to monitor the brain as an index organ.