Cerebral Desaturation Research Articles

Limitation of Near Infrared Spectroscopy Cerebral Oximetry in Predicting Neurologic Intolerance during Carotid Artery Stenting with Proximal Protection

AbstractProximal balloon occlusion prior to carotid artery stenting is considered a relatively safe practice during endovascular treatment of carotid artery stenosis. Transient neurological deterioration affecting the ipsilateral hemisphere is seen soon after balloon inflation, when placed proximal to the stenotic segment. This occurs in cases of bilateral carotid disease due to insufficient collateral blood flow from the contralateral side. Near infrared spectroscopy cerebral oximetry (NIRS) is a valuable tool in detecting hypoperfusion- induced cerebral tissue desaturation (rSO2) during these procedures. This helps the interventional radiologist to deflate the balloon at the earliest to re-establish the cerebral blood flow. The non-invasive nature and continuous real-time interpretation make NIRS an attractive adjunct in the neuroanesthesiolgist's armamentarium for monitoring cerebral ischemia. However, significant contribution from chromophores in the extra-cerebral tissues and external carotid artery circulation can limit its sensitivity during occlusion of the internal carotid artery. In our case, it did not reflect brain ischemia during hypotension and when the neurologic symptoms were obvious. Commonly available cerebral oximetry sensors placed over the frontal region do not cover the parietal lobe where ischemia is likely to occur during occlusion of the carotid artery. In such scenarios, it has been shown that multi-channel NIRS has a better sensitivity in detecting cerebral ischemia. This case report highlights the importance of frequent neurological examination during carotid stenting as rSO2 values might not always suggest cerebral ischemia.

The Incidence and Magnitude of Cerebral Desaturation in Traumatic Brain Injury: An Observational Cohort Study.

Cerebral ischemia in patients with traumatic brain injury (TBI) may propagate secondary neurological injury. Episodes of cerebral ischemia can be revealed through the use of cerebral oximetry monitoring. The objective of this study was to determine the incidence and severity of regional cerebral oxygen (rSO2) desaturation (rSO2<65%) in patients with severe TBI. Secondary outcomes included changes in other monitoring parameters associated with cerebral desaturation. In this single-center prospective observational cohort study, cerebral oximetry data were collected continuously for up to 72 hours in 18 adult patients with a diagnosis of severe nonpenetrating TBI who were being mechanically ventilated and undergoing intracranial pressure (ICP) monitoring an in intensive care unit in Canada. Mean arterial pressure (MAP), ICP, and cerebral perfusion pressure were collected at 5-minute intervals during the study period. Twelve of 18 (67%) patients experienced an episode of cerebral desaturation. The median (interquartile range) nadir rSO2 was 57% (51% to 62%). The duration of desaturation was 265 (57 to 1277) minutes or 8.1% (2.6% to 26.0%) of recording time. In all patients, a linear regression analysis of the area under threshold of 65% for rSO2 was moderately correlated with the area above an ICP threshold of 20 mm Hg (R2=0.52; P<0.01). Similarly, there was a modest correlation between rSO2 and MAP (R2=0.41; P<0.01). These relationships also held true for those patients who experienced cerebral desaturation. Patients having episodes of ICP >20 mm Hg were 6 times more likely to have a cerebral desaturation (relative risk: 6.0; 95% confidence interval: 1.3-34.7). Cerebral desaturations occur frequently in patients with severe TBI, and their duration can be protracted. Episodes of desaturation were moderately correlated with increased ICP and decreased MAP.

Can Cerebral Near-infrared Spectroscopy Predict Cerebral Ischemic Events in Neurosurgical Patients? A Narrative Review of the Literature.

Cerebral near-infrared spectroscopy (NIRS) is considered a valuable noninvasive modality for cerebral oxygenation monitoring during cardiovascular surgery and cardiac arrest. We assessed the capability of cerebral NIRS to predict cerebral desaturation and the related neurological outcomes in neurosurgical patients. A literature search in different electronic medical databases was performed from inception to January 2018. A total of 286 citations were found and finally 48 studies were retrieved, only 7 of these were eligible and included for review. A meta-analysis was not feasible because of high heterogeneity of patients' groups, different NIRS techniques used in the studies and different outcome criteria selected. The qualitative assessment showed controversial data on the threshold value of cerebral near-infrared spectroscopy used for detecting cerebral ischemia in neurosurgical patients. The evidence on the selected studies is not strong enough, at the moment, to recommend cerebral NIRS as a mandatory monitor to detect cerebral deoxygenation able to predict the future neurological outcome in neurosurgical patients. Further studies are needed to validate a threshold value for cerebral ischemia and the relationship between NIRS-detected cerebral desaturation and clinical outcome in the neurosurgical population.

A practical approach to cerebral near-infrared spectroscopy (NIRS) directed hemodynamic management in noncardiac pediatric anesthesia.

Safeguarding cerebral function is of major importance during pediatric anesthesia. Premature, ex-premature, and full-term neonates can be vulnerable to physiological changes that occur during anesthesia and surgery. Data from studies performed during pediatric cardiac surgery and in neonatal/pediatric intensive care units have shown the benefits of near-infrared spectroscopy (NIRS) monitoring of regional cerebral oxygenation (c-rSO2 ). However, NIRS monitoring is seldom used during noncardiac pediatric anesthesia. Despite compelling evidence that blood pressure does not reflect end-organ perfusion, it is still regarded as the most important determinant of cerebral perfusion and the most relevant hemodynamic management target parameter by most (pediatric) anesthetists. The principle of NIRS monitoring is not self-explanatory and sometimes seems even counterintuitive, which may explain why many anesthesiologists are reserved regarding its use. The first part of this paper is dedicated to a clinical introduction to NIRS monitoring. Despite scientific efforts, it has not yet been possible to define individual lower limit c-rSO2 values and it is unlikely this will succeed in the near future. Nonetheless, published treatment algorithms usually specify c-rSO2 values which may be associated with cerebral hypoxia. Our treatment guideline for maintaining sufficient cerebral oxygenation differs fundamentally from all previously published approaches. We define a baseline c-rSO2 value, registered in the awake child prior to anesthesia induction, as the lowest acceptable limit during anesthesia and surgery. The cerebral rSO2 is the single target parameter, while blood pressure, heart rate, Pa CO2 , and SaO2 are major parameters that determine the c-rSO2. Cerebral NIRS monitoring, interpreted together with its continuously available contributing parameters, may help avoid potentially harmful episodes of cerebral desaturation in anesthetized pediatric patients.

The relationship between the time of cerebral desaturation episodes and outcome in aneurysmal subarachnoid haemorrhage: a preliminary study

In this preliminary study we investigated the relationship between the time of cerebral desaturation episodes (CDEs), the severity of the haemorrhage, and the short-term outcome in patients with aneurysmal subarachnoid haemorrhage (aSAH). Thirty eight patents diagnosed with aneurysmal subarachnoid haemorrhage were analysed in this study. Regional cerebral oxygenation (rSO2) was assessed using near infrared spectroscopy (NIRS). A CDE was defined as rSO2 < 60% with a duration of at least 30 min. The severity of the aSAH was assessed using the Hunt and Hess scale and the short-term outcome was evaluated utilizing the Glasgow Outcome Scale. CDEs were found in 44% of the group. The total time of the CDEs and the time of the longest CDE on the contralateral side were longer in patients with severe versus moderate aSAH [h:min]: 8:15 (6:26–8:55) versus 1:24 (1:18–4:18), p = 0.038 and 2:05 (2:00–5:19) versus 0:48 (0:44–2:12), p = 0.038. The time of the longest CDE on the ipsilateral side was longer in patients with poor versus good short–term outcome [h:min]: 5:43 (3:05–9:36) versus 1:47 (0:42–2:10), p = 0.018. The logistic regression model for poor short-term outcome included median ABP, the extent of the haemorrhage in the Fisher scale and the time of the longest CDE. We have demonstrated that the time of a CDE is associated with the severity of haemorrhage and short-term outcome in aSAH patients. A NIRS measurement may provide valuable predictive information and could be considered as additional method of neuromonitoring of patients with aSAH.

Regional cerebral oxygen saturation and postoperative delirium in endovascular surgery: a prospective cohort study

BackgroundDelirium is an acute mental disorder and common postoperative complication. Monitoring regional cerebral oxygen saturation (rSO2) in endovascular therapeutic surgery may allow real-time monitoring of cerebral desaturation, avoiding profound cerebral dysfunction, and reducing the incidence of delirium. We sought to examine the incidence of delirium in patients undergoing endovascular surgery.MethodsThis was a clinical cohort trial (registered with http://www.clinicaltrials.gov [NCT02356133]). We monitored the rSO2 of 43 patients undergoing general anesthesia and cerebral endovascular surgery. The occurrence of delirium after surgery was recorded with the Confusion Assessment Method (CAM). Multivariate logistic regression was performed to identify the main predictor of delirium.ResultsrSO2 was significantly different between the delirium and no-delirium groups. The occurrence of delirium was 35% in our cohort, and higher rSO2 desaturation scores were significantly associated with profound delirium (higher CAM score; odds ratio = 1.002; P = 0.021). The maximum declines of systolic blood pressure were 24.86 (21.78–27.93) and 32.98 (28.78–37.19) in the no-delirium and delirium groups, respectively, which were significantly different (P = 0.002) but not closely associated with delirium in multivariate analysis (P = 0.512). Anesthesia, mechanical ventilation duration, and having two vascular risk factors differed significantly between groups but were poorly associated with delirium outcome.ConclusionsElevated rSO2 desaturation score was predictive of the occurrence of postoperative delirium following endovascular surgery. Monitoring rSO2 is invaluable for managing controlled hypotension during endovascular surgery and reducing postoperative delirium.Trial registrationClinicalTrials.gov, NCT02356133. Registered 1 February 2015. All statistical analysis results submitted August 4, 2018.

Evaluation of cerebral oxygen perfusion during shoulder arthroplasty performed in the semi–beach chair position

The beach chair position is commonly used when performing shoulder arthroplasty. However, this position has been associated with hypotension, potentially leading to cerebral hypoperfusion, which may cause neurologic injury. In addition, shoulder arthroplasty cases are associated with longer operative times, posing a potentially greater risk of cerebral hypoperfusion. We aim to evaluate the risk of cerebral desaturation events (CDEs) during the course of total shoulder arthroplasty. Twenty-six patients undergoing shoulder arthroplasties were monitored for changes in cerebral perfusion. Seven specific time-points during the procedure were labeled for comparison of events: baseline, beach chair, incision, humeral broaching, glenoid reaming, glenoid component implantation, and humeral component implantation. Cerebral oxygen perfusion was measured using near-infrared spectroscopy. A CDEwas described as a decrease of oxygen saturation greater than 20%. Nineteeen of 25 subjects experienced a CDE. 42% of these patients experienced CDEs during semi-beach chair positioning. Patients experienced the largest oxygen saturation drop during semi-beach chair positioning. Transition from baseline to semi-beach chair was the only event to have a statistically significant decrease in cerebral perfusion (8%, P < .05). There was a statistically significant percentage change in mean oxygen saturation in the semi-beach chair interval (10%, P < .01) and the semi-beach chair to incision interval (7%, P < .01). Most patients experienced an intraoperative CDE, with greatest incidence during semi-beach chair positioning. The largest decline in cerebral oxygen saturation occurred during semi-beach chair positioning. Implant implantation was not associated with decrease in cerebral oximetry.

Cerebral Desaturation Events During Shoulder Arthroscopy in the Beach Chair Position.

The beach chair position (BCP) is commonly used position in upper extremity surgery. Although there are many advantages to surgery in this position, there are also potential drawbacks and described complications including devastating neurologic outcomes. The etiology of these complications is postulated to be due to the gravitational effects of the seated position leading to cerebral hypoperfusion. We review the current literature on intraoperative cerebral monitoring and neurocognitive complications with shoulder surgery performed in the BCP. A previous systematic review estimated the incidence of neurocognitive complications after surgery in the BCP to be 0.004%. However, the true incidence is unknown and is likely much more common. Reports of neurologic complications have revealed a need for heightened vigilance, alternative anesthesia techniques, and improved monitoring. Methods for monitoring have included near-infrared spectroscopy, a measurement of cerebral oximetry shown to reliably detect cerebral hypoperfusion. In this literature review, we sought to update the incidence of intraoperative cerebral desaturation events (CDEs) to investigate the relationship of CDEs to neurocognitive complications and to review recent reported cases of neurocognitive complications. Existing literature suggest that accurate intraoperative monitoring of cerebral perfusion may improve patient safety.

Effect of Compression Stockings on Cerebral Desaturation Events in Obese Patients Undergoing Shoulder Arthroscopy in the Beach Chair

Effect of Compression Stockings on Cerebral Desaturation Events in Obese Patients Undergoing Shoulder Arthroscopy in the Beach Chair

Low vs high hemoglobin trigger for transfusion in vascular surgery: a randomized clinical feasibility trial

AbstractCurrent guidelines advocate to limit red blood cell (RBC) transfusion during surgery, but the feasibility and safety of such a strategy remain unclear, as the majority of evidence is based on postoperatively stable patients. We assessed the effects of a protocol aiming to restrict RBC transfusion throughout hospitalization for vascular surgery. Fifty-eight patients scheduled for lower limb bypass or open abdominal aortic aneurysm repair were randomly assigned, on hemoglobin drop below 9.7 g/dL, to either a low-trigger (hemoglobin < 8.0 g/dL) or a high-trigger (hemoglobin < 9.7 g/dL) group for RBC transfusion. Near-infrared spectroscopy assessed intraoperative oxygen desaturation in brain and muscle. Explorative outcomes included nationwide registry data on death and major vascular complications. The primary outcome, mean hemoglobin within 15 days of surgery, was significantly lower in the low-trigger group, at 9.46 vs 10.33 g/dL in the high-trigger group (mean difference, −0.87 g/dL; P = .022), as were units of RBCs transfused (median [interquartile range (IQR)], 1 [0-2] vs 3 [2-6]; P = .0015). Although the duration and magnitude of cerebral oxygen desaturation increased in the low-trigger group (median [IQR], 421 [42-888] vs 127 [11-331] minutes × %; P = .0036), muscle oxygenation was unaffected. The low-trigger group associated to a higher rate of death or major vascular complications (19/29 vs 8/29; hazard ratio, 3.20; P = .006) and fewer days alive outside the hospital within 90 days (median [IQR], 76 [67-82] vs 82 [76-84] days; P = .049). In conclusion, a perioperative protocol restricting RBC transfusion successfully separated hemoglobin levels and RBC units transfused. Exploratory outcomes suggested potential harm with the low-trigger group and warrant further trials before such a strategy is universally adopted. This trial was registered at www.clinicaltrials.gov as #NCT02465125.

Impact of 2 Distinct Levels of Mean Arterial Pressure on Near-Infrared Spectroscopy During Cardiac Surgery: Secondary Outcome From a Randomized Clinical Trial.

Near-infrared spectroscopy (NIRS) is used worldwide to monitor regional cerebral oxygenation (rScO2) during cardiopulmonary bypass (CPB). Intervention protocols meant to mitigate cerebral desaturation advocate to increase mean arterial pressure (MAP) when cerebral desaturation occurs. However, the isolated effect of MAP on rScO2 is uncertain. The aim of the present study was in a randomized, blinded design to elucidate the effect of 2 distinct levels of MAP on rScO2 values during CPB.We hypothesized that a higher MAP would be reflected in higher rScO2 values, lower frequency of patients with desaturation, and a less pronounced cerebral desaturation load. This is a substudy of the Perfusion Pressure Cerebral Infarct trial, in which we investigated the impact of MAP levels during CPB on ischemic brain injury after cardiac surgery. Deviation in rScO2 was a predefined outcome in the Perfusion Pressure Cerebral Infarct trial. Patients were randomized to low MAP (LMAP; 40-50 mm Hg) or high MAP (HMAP; 70-80 mm Hg) during CPB. CPB pump flow was fixed at 2.4 L/min/m, and MAP levels were targeted using norepinephrine. Intraoperatively, NIRS monitoring was performed in a blinded fashion, with sensors placed on the left and right side of the patient's forehead. NIRS recordings were extracted for offline analysis as the mean value of left and right signal during prespecified periods. Mean rScO2 during CPB was defined as the primary outcome in the present study. The average MAP level during CPB was 67 mm Hg ± SD 5.0 in the HMAP group (n = 88) and 45 mm Hg ± SD 4.4 in the LMAP group (n = 88). Mean rScO2 was significantly lower in the HMAP group during CPB (mean difference, 3.5; 95% confidence interval, 0.9-6.1; P = .010). There was no difference in rScO2 values at specified time points during the intraoperative period between the 2 groups. Significantly more patients experienced desaturation below 10% and 20% relative to rScO2 baseline in the HMAP group (P = .013 and P = .009, respectively), and the cerebral desaturation load below 10% relative to rScO2 baseline was more pronounced in the HMAP group (P = .042). In a randomized blinded study, we observed that a higher MAP induced by vasopressors, with a fixed CPB pump flow, leads to lower mean rScO2 and more frequent and pronounced cerebral desaturation during CPB. The mechanism behind these observations is not clear. We cannot exclude extracranial contamination of the NIRS signal as a possible explanation. However, we cannot recommend increasing MAP by vasoconstrictors during cerebral desaturation because this is not supported by the findings of the present study.

Neuromonitoring in paediatric anaesthesia.

There has been a steady advance in neuromonitoring during anaesthesia. Inevitably much of the research is first done in adults and later in children. This review will focus on the recent paediatric publications (2017-2019) in two areas of neuromonitoring - measuring anaesthesia effect and cerebral perfusion and oxygenation. For EEG-derived depth monitors, the main recent advances have been in better understanding their performance in infants. For the first time, large multichannel EEG studies on infants have focused on understanding the basic principles of how anaesthesia impacts on the EEG of the developing brain in a way different to the older brain. Nociception monitors are beginning to be studied in children. In the area of optical neuromonitoring, studies show that cerebral desaturation during both general and spinal anaesthesia in infants is uncommon in neonates and infants. Further work emphasizes the importance of CO2 levels on cerebral oxygenation, and demonstrates impaired cerebral autoregulation in premature infants undergoing laparotomies. The impact of anaesthesia on the EEG of small infants has some gross similarities to older children but there are fundamental differences, which mandate separate calibration of anaesthesia depth monitors. The role of nociception monitors in children has yet to be defined. Cerebral oxygenation monitoring during paediatric anaesthesia is improving our understanding of cerebral perfusion in this period, but as with almost all monitoring, evidence that its use improves outcome is not yet available.

Cerebrovascular Disease and Perioperative Neurologic Vulnerability: A Prospective Cohort Study.

Background: Stroke is a devastating perioperative complication without effective methods for prevention or diagnosis. The objective of this study was to analyze evidence-based strategies for detecting cerebrovascular vulnerability and injury in a high-risk cohort of non-cardiac surgery patients.Methods: This was a single-center, prospective cohort study. Fifty patients undergoing non-cardiac surgery were recruited −25 with known cerebrovascular disease and 25 matched controls. Neurologic vulnerability was measured with intraoperative cerebral oximetry as the primary outcome. Perioperative neurocognitive testing and serum biomarker analysis (S-100β, neuron specific enolase, glial fibrillary acid protein, and matrix metalloproteinase-9) were measured as secondary outcomes.Results: Cerebral desaturation events (an oximetry decrease ≥20% from baseline or <50% absolute value for ≥3 min) occurred in 7/24 (29%) cerebrovascular disease patients and 2/24 (8.3%) controls (relative risk 3.5, 95% CI 0.81–15.2; P = 0.094). Cognitive function trends were similar in both groups, though overall scores (range: 1,500–7,197) were ~1 standard deviation lower in cerebrovascular patients across the entire perioperative period (−1,049 [95% CI −1,662, −436], P < 0.001). No significant serum biomarker differences were found between groups over time. One control patient experienced intraoperative hypoxic-ischemic injury, but no robust biomarker or oximetry changes were observed.Conclusions: Cerebrovascular disease patients did not demonstrate dramatic differences in cerebral oximetry, cognitive trajectory, or molecular biomarkers compared to controls. Moreover, a catastrophic hypoxic-ischemic event was neither predicted nor detected by any strategy tested. These findings support the need for novel research into cerebrovascular risk and vulnerability.

Shoulder surgery in beach chair position causing perioperative stroke: Four cases and a review of the literature

Perioperative stroke is a rare, but serious complication in shoulder-arthroscopy or arthroplasty. Recent literature suggests the beach chair position, widely used during shoulder surgery, might induce severe perioperative hypotension, and with this cerebral desaturation and ultimately perioperative stroke. In this article we report four cases of perioperative stroke in shoulder surgery. In all cases, patients underwent brief periods of hypotension, which might have caused perioperative stroke. Based on an analysis in our hospital, we think the prevalence of perioperative stroke during shoulder surgery is higher than reported. Surgeons should be aware of this risk when using the beach chair position.

Efficacy of Perioperative Goal-directed Fluid Therapy in Preventing Cerebral Desaturation and Postoperative Cognitive Dysfunction After Beach Chair Position Shoulder Surgery

Efficacy of Perioperative Goal-directed Fluid Therapy in Preventing Cerebral Desaturation and Postoperative Cognitive Dysfunction After Beach Chair Position Shoulder Surgery

Portal Hypertension Is Associated With Congestive Encephalopathy and Delirium After Cardiac Surgery

BackgroundVenous congestion might lead to congestive encephalopathy after cardiac surgery. However, objective signs of congestion have yet to be associated with delirium. Portal vein flow pulsatility is a congestion marker that may identify a subgroup of patients at risk. MethodsWe performed a retrospective study and a prospective study in patients undergoing cardiac surgery. Adult patients who underwent portal vein Doppler imaging by the attending physician during usual care in the intensive care unit were included in the retrospective cohort. For the prospective cohort, patients had a cognitive and echocardiographic evaluation the day before surgery and daily for 3 days after surgery. Delirium was independently assessed by the nursing staff in the prospective cohort. ResultsA total of 237 patients in the retrospective cohort and 145 patients in the prospective cohort were included, for whom 1074 portal Doppler evaluations were performed. An association was found between delirium and portal vein pulsatility in the retrospective cohort (odds ratio [OR], 2.69; confidence interval [CI], 1.47-4.90; P = 0.001). In the prospective cohort, significant associations were found between the presence of portal vein pulsatility and the development of cognitive dysfunction and asterixis assessed by the investigators (OR, 2.10; CI, 1.25-3.53; P = 0.005 and OR, 2.23; CI, 1.13; 4.41; P = 0.02, and delirium detected by the nursing staff (hazard ratio, 2.63; CI, 1.13-6.11; P = 0.025). Higher N-terminal pro-beta natriuretic peptide measurements (OR, 4.03; CI, 1.78-9.15; P = 0.001) and cerebral desaturations (OR, 2.54; CI, 1.12-5.76; P = 0.03) were associated with cognitive dysfunction. ConclusionThese data present an association among hepatic congestion, delirium, and encephalopathy in patients undergoing cardiac surgery. Further studies should explore whether those neurological complications may have a congestive origin in some patients.

The effect of continuous propofol versus dexmedetomidine infusion on regional cerebral tissue oxygen saturation during cardiopulmonary bypass.

Cerebral oxygen desaturation can arise during various durations of cardiopulmonary bypass (CBP), thus continuous monitoring is necessary. This desaturation may account for distinct neuropsychological deficits. Near-infrared spectrophotometry (NIRS) is a non-invasive method that offers many advantages for monitoring cerebral oxygenation. The aim of this study was to compare the outcome of propofol and dexmedetomidine on cerebral regional oxygen saturation (rScO2) during CPB and on postoperative cognitive dysfunction. 50 patients anticipated for open heart surgeries were encompassed in the study. Patients were divided into 2 groups, group P (receiving propofol) and group D (receiving dexmedetomidine) during CPB. Both groups were studied for variations in right and left rScO2 as well as postoperative cognitive dysfunction using the Mini Mental State Examination Score (MMSE) test. The results showed no significant difference in both groups of the study, with an increase in rScO2 on the right and left side in T1 compared to T0 and maximum increase in T3-4-5, then a decrease in T6-7. With regard to the cognitive dysfunction there was a decrease in the values at 1 h in both groups without significant difference; after 1 week MMSE values returned to baseline values. Propofol and dexmedetomidine infusion used during CPB preserve the rScO2 and do not affect the neurological outcome.

Optimizing cerebral oxygenation in cardiac surgery: A randomized controlled trial examining neurocognitive and perioperative outcomes

ObjectiveThe study objective was to determine whether targeted therapy to optimize cerebral oxygenation is associated with improved neurocognitive and perioperative outcomes. MethodsIn a prospective trial, intraoperative cerebral oximetry monitoring using bilateral forehead probes was performed in cardiac surgical patients who were randomly assigned to an intervention group in which episodes of cerebral oxygen desaturation (<60% for >60 consecutive seconds at either probe) triggered an intervention protocol or a control group in which the cerebral oximetry data were hidden from the clinical team, and no intervention protocol was applied. Cognitive testing was performed preoperatively and at postoperative months 3 and 6; domains studied were response speed, processing speed, attention, and memory. Perioperative outcomes studied were death, hospital length of stay, intensive care unit length of stay, postoperative day of extubation, time on mechanical ventilation, intensive care unit delirium, Sequential Organ Failure Assessment on intensive care unit admission, and intensive care unit blood transfusion. ResultsGroup mean memory change scores were significantly better in the intervention group at 6 months (0.60 [standard error, 0.30] vs −0.17 [standard error, 0.33], adjusted P = .008). However, presence, duration, and severity of cerebral desaturation were not associated with cognitive change scores. Perioperative outcomes did not differ between the intervention and control groups. ConclusionsTargeted therapy to optimize cerebral oxygenation was associated with better memory outcome in a group of cardiac surgical patients. Some aspects of the protocol other than desaturation duration and severity contributed to the observed neuroprotective effect.

Unilateral Cerebral Oxygen Desaturation during Hypothermic Circulatory Arrest and Retrograde Cerebral Perfusion：A Case of Partial Anomalous Pulmonary Venous Connection

Unilateral Cerebral Oxygen Desaturation during Hypothermic Circulatory Arrest and Retrograde Cerebral Perfusion：A Case of Partial Anomalous Pulmonary Venous Connection

A Pilot Randomized Controlled Study of Mild Hypercapnia During Cardiac Surgery With Cardiopulmonary Bypass

To test whether targeted therapeutic mild hypercapnia (TTMH) would attenuate cerebral oxygen desaturation detected using near-infrared spectroscopy during cardiac surgery requiring cardiopulmonary bypass (CPB). Randomized controlled trials. Operating rooms and intensive care unit of tertiary hospital. The study comprised 30 patients undergoing cardiac surgery with CPB. Patients were randomly assigned to receive either standard carbon dioxide management (normocapnia) or TTMH (target arterial carbon dioxide partial pressure between 50 and 55 mmHg) throughout the intraoperative period and postoperatively until the onset of spontaneous ventilation. Relevant biochemical and hemodynamic variables were measured, and cerebral tissue oxygen saturation (SctO2) was monitored with near-infrared spectroscopy. Patients were followed-up with neuropsychological testing. Patient demographics between groups were compared using the Fisher exact and Mann-Whitney tests, and SctO2 between groups was compared using repeated measures analysis of variance. The median patient age was 67 years (interquartile range [IQR] 62-72 y), and the median EuroSCORE II was 1.1. The median CPB time was 106 minutes. The mean intraoperative arterial carbon dioxide partial pressure for each patient was significantly higher with TTMH (52.1 mmHg [IQR 49.9-53.9 mmHg] v 40.8 mmHg [IQR 38.7-41.7 mmHg]; p < 0.001) as was pulmonary artery pressure (23.9 mmHg [IQR 22.4-25.3 mmHg] v 18.5 mmHg [IQR 14.8-20.7 mmHg]; p = 0.004). There was no difference in mean percentage change in SctO2 during CPB in the control group for both hemispheres (left: -6.7% v -2.3%; p = 0.110; right: -7.9% v -1.0%; p = 0.120). Compliance with neuropsychological test protocols was poor. However, the proportion of patients with drops in test score >20% was similar between groups in all tests. TTMH did not increase SctO2 appreciably during CPB but increased pulmonary artery pressures before and after CPB. These findings do not support further investigation of TTMH as a means of improving SctO2 during and after cardiac surgery requiring CPB.