Risks and Association of Impaired Cerebral Autoregulation With Outcomes in Aortic Arch Surgery: A Single-center, Retrospective Cohort Study

BackgroundImpairment of cerebral autoregulation (CA) has been observed in patients undergoing cardiopulmonary bypass (CPB), but little is known about its risks and associations with outcomes. The objective of this study was to analyze the risks of impaired CA, based on cerebral oximetry index (COx), in patients undergoing total aortic arch replacement with CPB and moderate hypothermic circulatory arrest (MHCA). We also evaluated the association between impaired CA and patient outcomes.MethodsOne hundred fifteen four adult patients who underwent total aortic arch replacement with stented elephant trunk implantation under CPB and MHCA at our hospital were retrospectively analyzed. Patients were defined as having new-onset impaired CA if post-CPB COx > 0.3, calculated based on a moving linear correlation coefficient between regional cerebral oxygen saturation (rScO2) and mean blood pressure (MAP). Pre- and intraoperative factors were tested for independent association with impaired CA. Postoperative outcomes were compared between patients with normal and impaired CA.ResultsIn our 154 patients, 46(29.9%) developed new-onset impaired CA after CPB with MHCA. Multivariate analysis revealed a prolonged low rScO2 (rScO2 <55%) independently associated with onset of impaired CA, and receiver operating charactoristic curve showed a cutoff value at 40 min (sensitivity, 89.5%; specificity, 68.0%). Compared with normal CA patients, those with impaired CA showed a significantly higher rates of in-hospital mortality and postoperative complications.ConclusionProlonged low rScO2 (rScO2 <55%) during aortic arch surgery was closely related to onset of impaired CA. Impaired CA remained associated with the increased rates of postoperative complications and in-hospital mortality.Trial registration: ChiCTR1800014545 with registered date 20/01/2018.

A Comprehensive Review of Cerebral Oximetry in Cardiac Surgery

Background: Patients who undergo cardiac surgery are at increased risk of stroke, postoperative cognitive decline, and delirium. These neurocognitive complications have led to increased costs, intensive care unit stays, morbidity, and mortality. As a result, there is a significant push to mitigate any neurological complications in cardiac surgery patients. Near-infrared spectroscopy to measure regional cerebral oxygen saturations has gained consideration due to its non-invasive, user-friendly, and relatively inexpensive nature. Aim of Study: To provide a comprehensive summary of cerebral oximetry in cardiac surgery. The review interrogates multiple systematic reviews assessing different outcomes in cardiac surgery to assess if cerebral oximetry is effective. Further, the review analyzes all available interventions for an acute desaturation to determine the efficacy of individual interventions. Methods: A narrative review of randomized controlled trials, observational studies, and systematic reviews with metanalyses were performed through August 2021. Results: There is significant heterogeneity amongst studies regarding the definition of a clinically significant cerebral desaturation. In addition, the assessment of neurocognitive outcomes has large variability, making metanalysis challenging. To date, cerebral oximetry use during cardiac surgery has not been associated with improvements in neurocognitive outcomes, morbidity, or mortality. The evidence to support particular interventions for an acute desaturation is equivocal. Conclusions: Future research is needed to quantify a clinically significant cerebral desaturation and to determine which interventions for an acute desaturation effectively improve clinical outcomes.

Suppression of Electrographic Seizures Is Associated with Amelioration of QTc Interval Prolongation in Patients with Traumatic Brain Injury

Introduction: Disorders in electroencephalography (EEG) are commonly noted in patients with traumatic brain injury (TBI) and may be associated with electrocardiographic disturbances. Electrographic seizures (ESz) are the most common features in these patients. This study aimed to explore the relationship between ESz and possible changes in QTc interval and spatial QRS-T angle both during ESz and after ESz resolution. Methods: Adult patients with TBI were studied. Surface 12-lead ECGs were recorded using a Cardiax device during ESz events and 15 min after their effective suppression using barbiturate infusion. The ESz events were diagnosed using Masimo Root or bispectral index (BIS) devices. Results: Of the 348 patients considered for possible inclusion, ESz were noted in 72, with ECG being recorded in 21. Prolonged QTc was noted during ESz but significantly ameliorated after ESz suppression (540.19 ± 60.68 ms vs. 478.67 ± 38.52 ms, p < 0.001). The spatial QRS-T angle was comparable during ESz and after treatment. Regional cerebral oximetry increased following ESz suppression (from 58.4% ± 6.2 to 60.5% ± 4.2 (p < 0.01) and from 58.2% ± 7.2 to 60.8% ± 4.8 (p < 0.05) in the left and right hemispheres, respectively). Conclusion: QTc interval prolongation occurs during ESz events in TBI patients but both it and regional cerebral oximetry are improved after suppression of seizures.

The Effect of Volume Controlled and Pressure Controlled Ventilation Modes on Cerebral Oximetry and Blood Gas Status in Laparoscopic Cholecystectomy, A Randomized Controlled Trial

Background: To compare the volume-controlled and pressure-controlled ventilation modes with near infrared spectroscopy (NIRS) cerebral oximetry and blood gas status in laparoscopic cholecystectomyMethods: Seventy patients (n=70), who underwent elective laparoscopic cholecystectomy operation were randomized into two groups (volume control ventilation - group V, pressure control ventilation - group P). Demographic data (age, gender, body mass index) and operative data (anesthesia, surgery, and insufflation durations) were recorded. Patients’ single derivation electrocardiogram, pulse oximetry, non-invasive arterial pressure, NIRS cerebral oximetry and end-tidal CO2 parameters were recorded. Measurements were done at the start of anesthesia (T0), at the end of intubation (T1), 5 minutes after the insufflation (T2), at the time just before desufflation (T3) and 5 minutes after desufflation (T4).The patients’ heart rate, systolic and diastolic arterial pressure, saturation of pulse oximetry, and NIRS values were recorded for time points. Additionally, arterial gas results and mechanical ventilation parameters were recorded as well. Results: No significant difference was found in age, sex, body mass index. Operation, anesthesia and insufflation durations were similar for the groups. In Group P, NIRS right T1-2-3 averages and NIRS left T2-3 averages were significantly higher than Group V (p=0.030, p=0.001, p=0.001, p=0.006, p=0.002 respectively). In Group P T1-T2-T4, mean peak pressures and mean plateau pressures were significantly lower than Group V (p=0.003, p=0.001, p<0.001, p=0.011, p=0.001, p<0.001 respectively).Conclusion: Mechanical ventilation that performed in pressure-control ventilation mode is resulted with better tissue oxygenation than volume-control ventilation mode. In pressure-control ventilation mode, peak pressure and plateau pressure were lower.Registration of study at ClinicalTrials.gov was made at 25/01/2021 with the NCT04723043 number.

Multicenter study: outcomes of carotid endarterectomy depending on configuration of circle of Willis

BACKGROUND: The circle of Willis (CW) is an important network of collaterals that provide compensatory redistribution of hemodynamic load. Several studies showed that the CW is open in approximately 50%90% of cases, and the number of missing segments correlates with low brain tolerance to ischemia in internal carotid artery (ICA) compression. Currently, studies dedicated to the relationship of different configurations of CW with the risk of ischemic brain damage. AIM: The analyze the immediate results of eversion carotid endarterectomy (CEA) in patients with different configurations of the structure of the CW. MATERIALS AND METHODS: We included 641 patients with hemodynamically significant stenosis of the internal carotid arteries (ICA) in a study period from 2010 to 2020. All patients underwent multispiral computed tomography with angiography of the extracranial and CW arteries. Based on the structural variants of the CW, six groups of patients were studied: group 1 (64.9%, n = 416) closed posterior part (CPP) with the existence of posterior communicative artery (PCA) and P1 segment of the posterior cerebral artery (PCerA); group 2 (27%, n = 173) an intermediate structure of the posterior part (IPP) with hypoplasia of the PCA or PCerA; group 3 (8.1%, n = 52) open posterior part (OPP) with the absence of PCA or PCerA; group 4 (85.95%, n = 551) closed anterior part (CAP) with the presence of the anterior communicating artery (ACA) and A1 segment of the anterior cerebral artery (ACerA); group 5 (7.95%, n = 51) an intermediate structure of the anterior part (IAP) with hypoplasia of ACA or ACerA; group 6 (6.1%, n = 39) open anterior part (OAP) with the absence of ACA or ACerA. To assess the compensatory potentials of the brain, all patients underwent measurement of the retrograde pressure in the ICA and intraoperative cerebral oximetry. RESULTS: In the postoperative period, 1 death was recorded in group 4 (CAP) due to a hemorrhagic transformation in the zone of ischemic stroke, on the background development of hyperperfusion syndrome. The largest number of ischemic strokes of the cardioembolic subtype was diagnosed in the ACerA territory in the presence of an unstable atherosclerotic plaque: group 1 (CPP) 0%; group 2 (IPP) 0%; group 3 (OPP) 0.24%, n = 1; group 4 (CAP) 0.18%, n = 1; group 5 (IAP) 1.96%, n = 1; group 6 (OAP) 5.1%, n = 2; p 0.9999. The probable cause was embolization against the background increase in the arterial pressure before ICA clamping. In turn, the majority of ischemic strokes of the hemodynamic subtype developed in the territory of PCerA: group 1 (CPP) 0%; group 2 (IPP) 1.73%, n = 3; group 3 (OPP) 3.8%, n = 2; group 4 (CAP) 0.18%, n = 1; group 5 (IAP) 0%; group 6 (OAP) 2.56%, n = 1; p 0.9999. This pattern coincided with the largest number of patients with CW of the IPP and OPP types among all open variants of the structure. CONCLUSION: Parameters of retrograde pressure in the ICA and intraoperative cerebral oximetry do not always demonstrate the need for a temporary shunt (TS). Due to the opened structure of CW, the redistribution of blood flow occurs with the formation of zones of hypo- and hyperperfusion, causing ischemic alterations in the brain matter. Thus, in order to maintain adequate cerebral hemodynamics, to mitigate the effect of hypo- and hyperperfusion, and reduce the risk of ischemic stroke, the open variant of the CW structure should be considered as an indication for a TS.

REBOA-Assisted Resuscitation in Non-Traumatic Cardiac Arrest due to Massive Pulmonary Embolism: A Case Report with Physiological and Practical Reflections

We present the case of a 36-year old woman who suffered a non-traumatic out-of-hospital cardiac arrest. The resuscitation attempt included the use of a resuscitative endovascular balloon occlusion of the aorta (REBOA) catheter which resulted in a return of spontaneous circulation and distinct improvements in arterial blood pressure, end-tidal CO2 and cerebral oximetry values. This suggests that the use of REBOA may improve the rate of both survival and favorable neurologic outcome and warrants further study.

Cerebral Oximetry Measurements Results Depending on a Preclinical Skull Phantom Model

It is more common to perform non-invasive examination during general anaesthesia to ensure effective perioperative patient care. To achieve these results, researchers and clinicians are seeking out different technologies and developing new equipment. One such apparatus is a cerebral oximeter, which is used during cardiac surgery with cardiopulmonary bypass for neuroprotection management for reducing risk of postoperative neurological injury (cerebral stroke, neurocognitive dysfunction, and cerebral haemorrhage). A cerebral oximeter performs non-invasive transcutaneous measurements using near infrared radiation to assess the oxygenation of tissues. The objective of the study was to determine if the angle and thickness of a patient’s skull affects measurements. Intralipid water solution, gelatine, and ink were used to make six phantoms with skull thickness ranging from 6 to 11 mm. All phantoms were bent froma0to20 degrees angle. The cerebral oximeter SOMETICS INVOS 5100C was used to perform regional oximetry measurements. For skull thickness of 11 mm, the rSO2 was 45.8% (SD 0.96); for skull thickness of 10 mm, the rSO2 was 45.25% (SD 2.22); for skull thickness of 9 mm, the rSO2 was 32% (SD 1.63); for skull thickness of 8 mm, the rSO2 was 17% (SD 1.83); for skull thickness of 7 mm, the rSO2 was 15% (SD 0); for skull thickness of 6 mm, the rSO2 was 15% (SD 0). No significant changes were observed regarding the angle of the skull phantom. The thickness of the bone layer of the skull phantom affected the regional oximetry results, whereas the angle of the skull did not affect it.