Changes In Cerebral Oxygen Saturation Research Articles

Electroencephalography as a tool to predict cerebral oxygen metabolism during deep-hypothermic circulatory arrest in neonates with critical congenital heart disease

ObjectivesRecent research suggests that increased cerebral oxygen use during surgical intervention for neonates with congenital heart disease may play a role in the development of postoperative white matter injury. The objective of this study is to determine whether increased cerebral electrical activity correlates with greater decrease of cerebral oxygen saturation during deep hypothermic circulatory arrest. MethodsNeonates with critical congenital heart disease requiring surgical intervention during the first week of life were studied. All subjects had continuous neuromonitoring with electroencephalography and an optical probe (to quantify cerebral oxygen saturation) during cardiac surgical repair that involved the use of cardiopulmonary bypass and deep hypothermic circulatory arrest. A simple linear regression was used to investigate the association between electroencephalography metrics before the deep hypothermic circulatory arrest period and the change in cerebral oxygen saturation during the deep hypothermic circulatory arrest period. ResultsSixteen neonates had both neuromonitoring modalities attached during surgical repair. Cerebral oxygen saturation data from 5 subjects were excluded due to poor data quality, yielding a total sample of 11 neonates. A simple linear regression model found that the presence of electroencephalography activity at the end of cooling is positively associated with the decrease in cerebral oxygen saturation that occurs during deep hypothermic circulatory arrest (P < .05). ConclusionsElectroencephalography characteristics within 5 minutes before the initiation of deep hypothermic circulatory arrest may be useful in predicting the decrease in cerebral oxygen saturation that occurs during deep hypothermic circulatory arrest. Electroencephalography may be an important tool for guiding cooling and the initiation of circulatory arrest to potentially decrease the prevalence of new white matter injury in neonates with critical congenital heart disease.

Differences in Cerebral Oxygenation in Cardiogenic and Respiratory Cardiac Arrest Before, During, and After Cardiopulmonary Resuscitation.

We compared the changes in cerebral oxygen saturation (ScO2) levels during cardiac arrest (CA) events using porcine models of ventricular fibrillation CA (VF-CA) and asphyxial CA (A-CA). Twenty female pigs were randomly divided into VF-CA and A-CA groups. We initiated cardiopulmonary resuscitation (CPR) 4 min after CA and measured the cerebral tissue oxygenation index (TOI) using near-infrared spectroscopy (NIRS) before, during, and after CPR. In both groups, the TOI was the lowest at 3-4 min after pre-CPR phase initiation (VF-CA group: 3.4 min [2.8-3.9]; A-CA group: 3.2 min [2.9-4.6]; p = 0.386). The increase in TOI differed between the groups in the CPR phase (p < 0.001); it increased more rapidly in the VF-CA group (16.6 [5.5-32.6] vs. 1.1 [0.6-3.3] %/min; p < 0.001). Seven pigs surviving for 60 min after the return of spontaneous circulation in the VF-CA group recovered limb movement, whereas only one in the A-CA group (p = 0.023) achieved movement recovery. The increase in the TOI did not differ significantly between the groups in the post-CPR phase (p = 0.341). Therefore, it is better to monitor ScO2 concomitantly with CPR initiation using NIRS to assess the responsiveness to CPR in clinical settings.

Changes in cerebral oxygen saturation with the Trendelenburg position and increased intraabdominal pressure in laparocopic rectal surgery.

Position changes and increased intra-abdominal pressure in laparoscopic interventions lead to some physiopathological changes. There is no definite information in the literature regarding cerebral oxygen saturation in patients undergoing colorectal surgery. Our aim was to investigate whether there is oxygen saturation change in the brain tissue in pneumoperitoneum and the Trendelenburg position during laparoscopic rectal surgery. Cerebral oxygen saturation was measured in 35 patients who underwent laparoscopic rectal surgery in the Trendelenburg position. Measurements were made under general anesthesia in the pneumoperitoneum and the Trendelenburg position. The values that are statistically affected by the position are systolic blood pressure, mean arterial blood pressure and cerebral oxygen saturation. The Trendelenburg position does not disturb the cerebral oxygen saturation and it causes an increase in saturation. After pneumoperitoneum occurred, changes in systolic blood pressure, mean arterial blood pressure and brain oxygen saturation were detected. Cerebral oxygen saturation increases with the formation of pneumoperitoneum. The Trendelenburg position and increased intraabdominal pressure during laparoscopic rectal surgery do not impair brain oxygen saturation.

FC092: The Relationship between Cerebrovascular Reactivity and Intradialytic Cerebral Perfusion

Abstract BACKGROUND AND AIMS Cerebral perfusion can decline in hemodialysis (HD) patients during HD and may have severe consequences on cerebral integrity. The declines in cerebral perfusion are often related to intradialytic changes in blood pressure (BP), indicating that the ability of cerebrovasculature to maintain perfusion during systemic BP drop is impaired. Preliminary data using transcranial Doppler ultrasound demonstrated that cerebrovascular reactivity (CVR), a physiologic mechanism for maintaining cerebral perfusion, is impaired in HD patients. we hypothesize that CVR can serve as a measure for how a patients’ cerebrovasculature can respond to intradialytic hypotension. We aim to measure CVR in a cohort of HD patients and evaluate the relationship between CVR, intradialytic BP fluctuation and risk of intradialytic cerebral hypoperfusion. METHOD In a cross-sectional analysis, we used resting state fMRI to estimate CVR and determine if CVR is related to changes in cerebral oxygen saturation (ScO2) measured during HD. We recruited ESRD patients ≥50 years of age who were treated with in-center HD to complete an MRI with T1 weighted anatomical images and resting state fMRI. CVR was obtained from the resting state fMRI data by first bandpass filtering and detrending the global blood oxygenation level dependent (BOLD) signal within the frequency range that correlated with end tidal CO2 (vasoactive stimulus for CVR). The CVR was then calculated as the coefficient relating the filtered fMRI signal to each unfiltered voxel. Intradialytic ScO2 was continuously measured during an entire HD session using near-infrared spectroscopy with oximetry sensors secured to the forehead. Change in cerebral perfusion was quantified as the % change in ScO2 from baseline during the HD session. Due to the forehead placement of our sensors, we focused our CVR analysis to the frontal brain regions. Univariate linear regression models were run within each region for association with change in ScO2. Further analysis added intradialytic BP change to the model. RESULTS We included 26 participants with complete MRI and ScO2 data in analysis. Mean (SD) age was 65.7 (7.1), 81% had hypertension and 69% had diabetes mellitus. On average, the systolic BP (SBP) and ScO2 declined during HD. Results demonstrated that lower CVR in the anterior cingulate gyrus (ACG r2 = 0.19; P = 0.03, Figure 1), insular cortex (IC, r2 = 0.19; P = 0.03, Figure 1) and posterior parahippocampal gyrus (PPG, r2 = 0.20; P = 0.02) regions were associated with a decrease in ScO2 during HD. When adding the change in SBP during HD to the model, the ACG (r2 = 0.35, &amp;lt;0.01) and IC (r2 = 0.26; P = 0.03) models remained significant with increased correlation coefficients. CONCLUSION We were able to demonstrate a relationship between lower CVR in frontal gray matter regions and greater decline in cerebral perfusion during HD. This relationship was further strengthened when adding the intradialytic change in SBP to the model. This suggests that both the hemodynamic fluctuations and the patient's ability to regulate cerebral perfusion are contributing factors for the risk of intradialytic cerebral hypoperfusion and subsequent cerebral ischemic injury in HD patients.

The Effect of Cerebral Oxygen Saturation Changes on Early Postoperative Neuropsychological Function in Patients Undergoing Cranial Surgery.

To compare the incidence of postoperative neuropsychological dysfunction in patients managed with cerebral saturation monitoring versus traditional approaches. A hundred patients undergoing elective intracranial surgery were divided into two groups to receive intraoperative management via cerebral saturation monitoring (Group O) or the conventional approach (Group C). The postoperative neuropsychological function was evaluated by the antisaccadic eye movement test (ASEM) and the Mini-Mental State Examination (MMSE). These tests were performed preoperatively and postoperatively on the first, second, and fifth days. The time for the modified Aldrete score to reach 9 (MAS 9), adverse effects, and pain using a Visual Analog Scale (VAS) scores were recorded. Patient characteristics and surgery data were not statistically different. The MAS 9 of group O was significantly lower than that of group C (p < 0.001). The MMSE at the postoperative 1, 2, and 5 days were significantly higher in Group O compared to Group C (p < 0.001). ASEM was similar between groups. Group O was subdivided according to the type of surgery applied with diagnosis, and there were no statistically significant between-group differences in terms of areas under the curve for the cerebral regional oxygen saturation. There was no between-group difference regarding the mean arterial pressure at any time perioperatively. The heart rate at 80, 90, 100, and 110 min intraoperatively was significantly higher in group C than in Group O. Intraoperative cerebral oxygenation monitoring can reduce patient mortality and morbidity by allowing early postoperative neurological evaluation to detect potential neurocognitive deficits.

Association of Ongoing Cerebral Oxygen Extraction During Deep Hypothermic Circulatory Arrest With Postoperative Brain Injury

Cardiac surgery utilizing circulatory arrest is most commonly performed under deep hypothermia (∼18°C) to suppress tissue oxygen demand and provide neuroprotection during operative circulatory arrest. Studies investigating the effects of deep hypothermic circulatory arrest (DHCA) on neurodevelopmental outcomes of patients with congenital heart disease give conflicting results. Here, we address these issues by quantifying changes in cerebral oxygen saturation, blood flow, and oxygen metabolism in neonates during DHCA and investigating the association of these changes with postoperative brain injury. Neonates with critical congenital heart disease undergoing DHCA were recruited for continuous intraoperative monitoring of cerebral oxygen saturation (ScO2) and an index of cerebral blood flow (CBFi) using 2 noninvasive optical techniques, diffuse optical spectroscopy (DOS) and diffuse correlation spectroscopy (DCS). Pre- and postoperative brain magnetic resonance imaging (MRI) was performed to detect white matter injury (WMI). Fifteen neonates were studied, and 11/15 underwent brain MRI. During DHCA, ScO2 decreased exponentially in time with a median decay rate of -0.04 min-1. This decay rate was highly variable between subjects. Subjects who had larger decreases in ScO2 during DHCA were more likely to have postoperative WMI (P=0.02). Cerebral oxygen extraction persists during DHCA and varies widely from patient-to-patient. Patients with a higher degree of oxygen extraction during DHCA were more likely to show new WMI in postoperative MRI. These findings suggest cerebral oxygen extraction should be monitored during DHCA to identify patients at risk for hypoxic-ischemic injury, and that current commercial cerebral oximeters may underestimate cerebral oxygen extraction.

Age-related cerebrovascular carbon dioxide reactivity in children with ventricular septal defect younger than 3years.

Impaired cerebrovascular reactivity to carbon dioxide was proposed to contribute to neurological morbidity in children undergoing cardiac surgery. The objective of this study was to assess carbon dioxide reactivity and regional cerebral oxygen saturation in children younger than 3years. This study enrolled children younger than 3years undergoing ventricular septal defect repair. The cohort was divided into three age groups: younger than 6months, 6-12months, and 12-36months. Under steady-state anesthesia, carbon dioxide reactivity was calculated by measuring changes in middle cerebral artery blood flow velocity using transcranial Doppler sonography. Regional cerebral oxygen saturation changes were measured by near-infrared spectroscopy while endtidal carbon dioxide pressure was adjusted from 30 to 45mmHg. Carbon dioxide reactivity showed a statistically significant increasing relationship with age (younger than 6months group: 4.42%±2.73%, 6-12months group: 5.86%±1.91%, 12-36months group: 7.58%±1.49%; P<.001). Regional cerebral oxygen saturation showed a statistically significant increasing relationship with age (younger than 6months group: 65%±6%, 6-12months group: 68%±5%, 12-36months group: 70%±5%; P=.027). Regional cerebral oxygen saturation showed a statistically significant increasing relationship with endtidal carbon dioxide pressure in all children (P<.001). Abnormal carbon dioxide reactivity is prevalent in children younger than 3years and the degree varies according to age.

Effect of Pulsatile Cardiopulmonary Bypass in Adult Heart Surgery.

This study aimed to examine the effect of pulsatile flow pattern on tissue perfusion, particularly cerebral tissue perfusion, at pre-determined intervals during CPB, as well as its effects on postoperative morbidity and mortality. This retrospective study included 134 adult patients, who underwent cardiac surgery with cardiopulmonary bypass (CPB). Patients were grouped based on the flow pattern used during CPB: non-pulsatile CPB group (N = 82) and pulsatile CPB group (N = 52). Cerebral oxygen saturation, arterial pH and arterial lactate levels were measured at four time points, during the operation and the 2 groups were compared with regard to changes over time as well as differences in postoperative outcomes. The 2 groups were similar, in terms of mean values and intraoperative changes in cerebral oxygen saturation and arterial pH. Non-pulsatile CABG group had significantly higher arterial lactate levels over the measurement period, which was not affected by the timing of the measurements. Postoperative drainage, duration of ventilation and duration of hospital stay significantly were higher and postoperative blood urea nitrogen significantly was lower in the non-pulsatile CPB group. Other postoperative outcomes were similar across the groups. Findings of this study do not support the superiority of pulsatile flow pattern during CPB, in terms of cerebral oxygen saturation or postoperative mortality/morbidity. Further and larger comparative studies are warranted before pulsatile blood flow pattern can be established as a routine clinical method.

Regional Cerebral Oxygen Saturation Changes After Decompressive Craniectomy for Malignant Cerebral Venous Thrombosis: A Prospective Cohort Study.

Decompressive craniectomy (DC) is a life-saving intervention for malignant cerebral venous thrombosis (CVT). Earlier studies have shown increase in cerebral oxygenation after DC in traumatic brain injury but similar studies are lacking in CVT. We hypothesized that regional cerebral (tissue) oxygen saturation (rSO2) on the side of CVT is lower than the contralateral side and improves after DC. In this prospective cohort study, rSO2 was monitored using near-infrared spectroscopy technique, before and after DC on both cerebral hemispheres. Data regarding factors likely to affect rSO2 such as systolic blood pressure, partial pressure of oxygen and carbon dioxide in blood (PaO2 and PaCO2), and hemoglobin were simultaneously collected. The primary outcome measure was pre-post change in rSO2 on the ipsilateral cerebral hemisphere. The secondary outcomes were in-hospital mortality and duration of postoperative hospital stay. Seventeen patients underwent DC during the 6-month study period. Their mean age was 39.2±12.4 years. The pre-post DC change in rSO2 on the hemisphere with CVT was significant (mean difference=3.6%; 95% confidence interval, 1.5-5.7; P=0.002). One patient died in the hospital. There was no difference in the duration of postoperative hospital stay (10 d [range, 6 to 21 d] vs. 14 d [range, 1 to 30 d], P=0.92) between patients with preoperative ipsilateral rSO2 <60% and >60%. There was no correlation between PaO2, PaCO2, systolic blood pressure, and hemoglobin with rSO2. Patients with malignant CVT had a lower rSO2 on ipsilateral side of the lesion, which improved significantly after DC. Preoperative rSO2 was not correlated with the duration of hospital stay.

Cerebral oxygen saturation monitoring in preeclamptic pregnant women undergoing cesarean section with spinal anesthesia: a prospective, observational study.

It has been suggested that cerebral oximetry can detect acute and chronic changes in cerebral oxygen saturation due to pregnancy related complications. Furthermore, regional cerebral oxygenation saturation (rcSO2) decreases were obtained during spinal anesthesia for cesarean section. The aim of this prospective observational study is to compare the effects of spinal anesthesia on rcSO2 in preeclamptic and normotensive pregnant women. Preeclamptic (Group P, n = 24) and normotensive (Group N, n = 25) women with gestational week 32 and above, and scheduled for cesarean section under spinal anesthesia were included in this study. In addition to routine monitoring, rcSO2 values obtained with right and left frontal cerebral sensors (rcSO2right and rcSO2left) were recorded before (baseline) spinal injection and during the surgery. The baseline rcSO2 values were similar in both groups. In Group P, rcSO2left values were higher than Group N only 3 and 5min after spinal injection. In Group N, rcSO2 values decreased from baseline 1, 3, 5, and 10min after spinal injection. In Group P, rcSO2 values decreased from baseline 1, 3, 5, 10, 30 and 35min after spinal injection and at the end of the operation. There was no difference between the number of declines and the patients with rScO2 below the cerebral hypoxic threshold. There was a positive correlation between rcSO2 and blood pressure only 5min after spinal injection, but no correlation with peripheral oxygen saturation was detected during the operation. There is decrease in rcSO2 values after spinal anesthesia correlating with hypotension in preeclamptic women. However, the decrease is less than that of normotensive pregnant women, especially the first 5min after spinal injection when the blood pressure is lowest. The clinical impact of these results and the relationship between cerebral desaturation and neurological complications remain to be determined.

S187. Cerebral oxygen saturation and cytochrome oxidase redox state in children with epilepsy: A pilot study - MULTICHANNEL NIRS for epilepsy seizure detection

Epilepsy remains a significant healthcare problem associated with significant morbidity and mortality. Electroencephalograms (EEGs) provide a means of identifying ongoing seizures. However, specialized equipment is needed to obtain and interpret data. There remains a need for technologies that are easily utilized and interpreted for the purpose of monitoring children in the time periods before, during and after seizure activity. NIRS cerebral oximetry works as a noninvasive measurement that allows continuous measurement of cerebral oxygen availability. This monitor serves as a surrogate to invasive measures of venous pO2, often obtained from the jugular vein to estimate cerebral oxygen levels. We recently published NIRS-EEG data with a limited number of NIRS probes in four patients with medically refractory epilepsy undergoing pre-surgical evaluation with ages ranging from 5 to 17 years. The purpose of this pilot study is to describe the relationship of regional cerebral oximetry and cytoximetry, measured using MULTICHANNEL NIRS (near-infrared spectroscopy) in the peri-ictal period in children with epilepsy. The hypothesis is: 1. Regional cerebral saturation of oxygen and/or cytochrome oxidase redox state will increase prior to the onset of seizure activity; 2. Regional cerebral saturation of oxygen and/or cytochrome oxidase redox state will have a varied response during seizure activity depending on the seizure type; 3. Regional cerebral saturation of oxygen and/or cytochrome oxidase redox state will return to baseline following cessation of seizure activity. The three goals for the research study are to: 1. Quantify the magnitude and direction of change of cerebral oxygen saturation and cytochrome oxidase redox state during the peri-ictal period in children with epilepsy; 2. Quantify the temporal relationship, magnitude and direction of change of cerebral oxygenation and cytochrome oxidase redox state in relationship to seizure type; 3. Measure the association of cerebral oxygenation and cytochrome oxidase redox state with systemic oxygen saturation, EEG findings and clinical status. Study subjects will include pediatric patients from birth to 18 years of age with a known seizure disorder who are being admitted to the epilepsy monitoring unit (EMU) or the ICU at CHW for further workup or medication management of their epilepsy. Children will be monitored per standard of care for the duration of their hospitalization, which typically is 3–5 days with the additional NIRS-EEG array added to their monitoring. Preliminary data shows varied regional cerebral oxygen saturation and/or cytochrome oxidase redox state during interictal period and seizure activity depending on the seizure type. The increased blood flow clearly coincided with epileptiform activity and continued to increase as the epileptiform activity built up. Regional cerebral oxygen saturation increased in the epileptogenic focus, perhaps due to loss of cerebrovascular autoregulation.

Changes in Cerebral Oxygenation in Preterm Infants With Progressive Posthemorrhagic Ventricular Dilatation

BackgroundOptimal timing of intervention in neonatal progressive posthemorrhagic hydrocephalus is often a difficult decision. Unchecked hydrocephalus can lead to irreversible brain injury through impaired perfusion, while placement of a shunt is not without long-term morbidity. The purpose of this study was to assess the use of near-infrared spectroscopy to measure changes in regional cerebral oxygen saturation as an indicator of cerebral perfusion in infants with progressive posthemorrhagic ventricular dilatation. MethodsNear-infrared spectroscopy was used to measure regional cerebral oxygen saturation for more than a one-hour period in infants within 24 hours of cranial ultrasound. Simultaneous pulse oximetry was recorded and oxygen extraction was calculated. Ventricular size was measured by ultrasound using the frontal-occipital horn ratio and compared with average oxygen saturation and oxygen extraction. Statistical analysis was done using the Spearman rank test and analysis of variance. ResultsVentricular measurements were made in 20 very low birth weight premature infants with periventricular-intraventricular hemorrhage and 12 infants with normal ultrasound scans. Ventricular dilatation was associated with lower cerebral oxygen saturation and higher oxygen extraction (P < 0.001). Progressive ventricular dilatation was inversely related to changes in cerebral oxygen saturation (P < 0.001). ConclusionsProgressive posthemorrhagic ventricular dilatation is associated with a significant decrease in cerebral oxygenation and increase in oxygen extraction suggesting a decrease in cerebral perfusion. Near-infrared spectroscopy could potentially provide additional clinical information to assist in determining optimal timing of surgical intervention in preterm infants with progressive ventricular enlargement.

Changes in cerebral oxygen saturation and haemoglobin concentration during paediatric cardiac surgery.

Although near-infrared spectroscopy (NIRS) enables bedside assessment of cerebral oxygenation, it provides little information on the cause of deoxygenation. The authors aimed to investigate the changes in cerebral oxygenation and haemoglobin concentration and their associations during paediatric cardiac surgery in order to elucidate the physiology underlying cerebral deoxygenation. An observational retrospective study on 399 patients who underwent paediatric cardiac surgery was conducted. With use of NIRS, cerebral oxygen saturation as expressed by tissue oxygen index (TOI) before and after surgery, concentration changes in oxygenated haemoglobin (Δ[HbO2]) and deoxygenated haemoglobin (Δ[HHb]) after surgery were studied as were the associations between these values and clinical variables. TOI decreased after surgery (preoperative versus postoperative value, 66.0% [56.9, 71.3] versus 63.2% [54.3, 69.4], median [25th, 75th percentile], P <0.001) and the decrease was greater in higher category groups in the Risk Adjusted Classification for Congenital Heart Surgery (RACHS-1). [HHb] increased from its baseline (+1.74 μmol/l [-1.57, +5.84], P <0.001) and the increase was greater in higher risk category groups. On the contrary, there was no evidence for a change in [HbO2] (+0.45 μmol/l [-4.76, +5.30], P=0.42). Cerebral oxygen saturation decreased after paediatric cardiac surgery and the decrease was greater in patients of higher risk groups. The increase in [HHb] was considered to play a predominant role in the cerebral deoxygenation noted, in particular in higher RACHS-1 category groups.

Assessment of risk factors for cerebral oxygen desaturation during neonatal and infant general anesthesia: an observational, prospective study.

BackgroundCerebral oxygen saturation (rSO2c) decrease from baseline greater than 20 % during infant cardiac surgery was associated with postoperative neurologic changes and neurodevelopmental impairment at 1 year of age. So far, there is no sufficient evidence to support the routine monitoring of rSO2c during general surgical procedures in children. We aimed to find out the frequency of cerebral desaturation 20 % or more from baseline and to identify possible predictors of change in cerebral oxygen saturation during neonatal and infant general surgery.MethodsForty-four infants up to 3 months of age were recruited. Before induction of anesthesia, two pediatric cerebral sensors were placed bilaterally to the forehead region and monitoring of regional cerebral saturation of oxygen was started and continued throughout the surgery. Simultaneously, mean arterial blood pressure (MAP), pulse oximetry (SpO2), heart rate (HR), endtidal CO2, expired fraction of sevoflurane and rectal temperature were recorded. The main outcome measure was rSO2c value drop-off ≥20 % from baseline. Mann-Whitney U-test, chi-squared test, simple and multiple linear regression models were used for statistical analysis.ResultsForty-three infants were analyzed. Drop-off ≥20 % in rSO2c from baseline occurred in 8 (18.6 %) patients. There were no differences in basal rSO2c, SpO2, HR, endtidal CO2, expired fraction of sevoflurane and rectal temperature between patients with and without desaturation 20 % or more from baseline. But the two groups differed with regard to gestation, preoperative mechanical ventilation and the use of vasoactive medications and red blood cell transfusions during surgery. Simple linear regression model showed, that gestation, age, preoperative mechanical ventilation and mean arterial pressure corresponding to minimal rSO2c value during anesthesia (MAPminrSO2c) were associated with a change in rSO2c values. Multiple regression model including all above mentioned variables, revealed that only MAPminrSO2c was predictive for a change in rSO2c values (β (95 % confidence interval) -0.28 (−0.52–(−0.04)) p = 0.02).ConclusionsCerebral oxygen desaturation ≥20 % from baseline occurred in almost one fifth of patients. Although different perioperative factors can predispose to cerebral oxygenation changes, arterial blood pressure seems to be the most important. Gestation as another possible risk factor needs further investigation.Trial registrationThe international registration number NCT02423369. Retrospectively registered on April 2015.Electronic supplementary materialThe online version of this article (doi:10.1186/s12871-016-0274-2) contains supplementary material, which is available to authorized users.

Efeitos da insuflação de dióxido de carbono sobre a oxigenação cerebral regional durante cirurgia laparoscópica em crianças: um estudo prospectivo

Laparoscopic surgery has become a popular surgical tool when compared to traditional open surgery. There are limited data on pediatric patients regarding whether pneumoperitoneum affects cerebral oxygenation although end-tidal CO2 concentration remains normal. Therefore, this study was designed to evaluate the changes of cerebral oxygen saturation using near-infrared spectroscope during laparoscopic surgery in children.The study comprised forty children who were scheduled for laparoscopic (Group L, n=20) or open (Group O, n=20) appendectomy. Hemodynamic variables, right and left regional cerebral oxygen saturation (RrSO2 and LrSO2), fraction of inspired oxygen, end-tidal carbon dioxide pressure (PETCO2), peak inspiratory pressure (Ppeak), respiratory minute volume, inspiratory and end-tidal concentrations of sevoflurane and body temperature were recorded. All parameters were recorded after anesthesia induction and before start of surgery (T0, baseline), 15min after start of surgery (T1), 30min after start of surgery (T2), 45min after start of surgery (T3), 60min after start of surgery (T4) and end of the surgery (T5).There were progressive decreases in both RrSO2 and LrSO2 levels in both groups, which were not statistically significant at T1, T2, T3, T4. The RrSO2 levels of Group L at T5 were significantly lower than that of Group O. One patient in Group L had an rSO2 value <80% of the baseline value.Carbon dioxide insufflation during pneumoperitoneum in pediatric patients may not affect cerebral oxygenation under laparoscopic surgery.

Changes in cerebral oxygen saturation during transcatheter aortic valve replacement.

Cerebral oxygen saturation (rSO2) is a non-invasive monitor used to monitor cerebral oxygen balance and perfusion. Decreases in rSO2 >20% from baseline have been associated with cerebral ischemia and increased perioperative morbidity. During transcatheter aortic valve replacement (TAVR), hemodynamic manipulation with ventricular pacing up to 180 beats per minute is necessary for valve deployment. The magnitude and duration of rSO2 change during this manipulation is unclear. In this small case series, changes in rSO2 in patients undergoing TAVR are investigated. Ten ASA IV patients undergoing TAVR with general anesthesia at a university hospital were prospectively observed. Cerebral oximetry values were analyzed at four points: pre-procedure (baseline), after tracheal intubation, during valve deployment, and at procedure end. Baseline rSO2 values were 54.5±6.9%. After induction of general anesthesia, rSO2 increased to a mean of 66.0±6.7%. During valve deployment, the mean rSO2 decreased <20% below baseline to 48.5±13.4%. In two patients, rSO2 decreased >20% of baseline. Cerebral oxygenation returned to post-induction values in all patients 13±10min after valve deployment. At procedure end, the mean rSO2 was 67.6±8.1%. As expected, rapid ventricular pacing resulting in the desired decrease in cardiac output during valve deployment was associated with a significant decrease in rSO2 compared to post-induction values. However, despite increased post-induction values in all patients, whether related to increased inspired oxygen fraction or reduced cerebral oxygen consumption under anesthesia, two patients experienced a significant decrease in rSO2 compared to baseline. Recovery to baseline was not immediate, and took up to 20min in three patients. Furthermore, baseline rSO2 in this population was at the lower limit of the published normal range. Significant cerebral desaturation during valve deployment may potentially be limited by maximizing rSO2 after anesthetic induction. Future studies should attempt to correlate recovery in rSO2 with recovery of hemodynamics and cardiac function, provide detailed neurological assessments pre and post procedure, determine the most effective method of maximizing rSO2 prior to hemodynamic manipulation, and provide the most rapid method of recovery of rSO2 following valve deployment.

Changes in cerebral oxygen saturation and early postoperative cognitive function after laparoscopic gastrectomy: a comparison with conventional open surgery.

BackgroundLaparoscopic gastrectomy requires a reverse-Trendelenburg position and prolonged pneumoperitoneum and it could cause significant changes in cerebral homeostasis and lead to cognitive dysfunction. We compared changes in regional cerebral oxygen saturation (rSO2), early postoperative cognitive function and hemodynamic variables in patients undergoing laparoscopic gastrectomy with those patients that underwent conventional open gastrectomy.MethodsSixty patients were enrolled in this study and the patients were distributed to receive either laparoscopic gastrectomy (laparoscopy group, n = 30) or open conventional gastrectomy (open group, n = 30). rSO2, end-tidal carbon dioxide tension, hemodynamic variables and arterial blood gas analysis were monitored during the operation. The enrolled patients underwent the mini-mental state examination 1 day before and 5 days after surgery for evaluation of early postoperative cognitive function.ResultsCompared to baseline value, rSO2 and end-tidal carbon dioxide tension increased significantly in the laparoscopy group after pneumoperitoneum, whereas no change was observed in the open group. No patient experienced cerebral oxygen desaturation or postoperative cognitive dysfunction. Changes in mean arterial pressure over time were significantly different between the groups (P < 0.001).ConclusionsBoth laparoscopic and open gastrectomy did not induce cerebral desaturation or early postoperative cognitive dysfunction in patients under desflurane anesthesia. However, rSO2 values during surgery favoured laparoscopic surgery, which was possibly related to increased cerebral blood flow due to increased carbon dioxide tension and the effect of a reverse Trendelenburg position.

Impact of Norepinephrine on Regional Cerebral Oxygenation During Cardiopulmonary Bypass.

Norepinephrine is used to increase mean arterial pressure during cardiopulmonary bypass. However, it has been suggested that norepinephrine could constrict cerebral arteries, reducing cerebral blood flow. The aim of this study, therefore, was to explore whether there was an association between doses of norepinephrine to maintain mean arterial pressure at ≈80 mmHg during cardiopulmonary bypass and cerebral oxygen saturation measured using near-infrared spectroscopy. Observational study. University hospital. Patients undergoing cardiac surgery (n = 45) using cardiopulmonary bypass. Norepinephrine was administered to maintain mean arterial pressure ≈80 mmHg during cardiopulmonary bypass. From initiation of cardiopulmonary bypass to removal of the aortic cross-clamp, norepinephrine dose, mean arterial pressure, partial pressure of arterial carbon dioxide, partial pressure of arterial oxygen, hemoglobin, and pump flow values were averaged over 1 minute, giving a total of 3,460 data points entered as covariates in a linear mixed model for repeated measurements, with cerebral oxygen saturation measured using near-infrared spectroscopy as outcome. There was no statistically significant association between norepinephrine dose to maintain mean arterial pressure and cerebral oxygen saturation (p = 0.46) in this model. Administration of norepinephrine to maintain mean arterial pressure ≈80 mmHg during cardiopulmonary bypass was not associated with statistically significant changes in cerebral oxygen saturation. These results indicated that norepinephrine could be used to increase mean arterial pressure during cardiopulmonary bypass without reducing cerebral oxygen saturation.

Changes in cerebral oxygen saturation during pediatric surgery in patients with cyanotic and non-cyanotic congenital heart defects

Changes in cerebral oxygen saturation during pediatric surgery in patients with cyanotic and non-cyanotic congenital heart defects

Effects of carbon dioxide insufflation on regional cerebral oxygenation during laparoscopic surgery in children: a prospective study

Background and objectivesLaparoscopic surgery has become a popular surgical tool when compared to traditional open surgery. There are limited data on pediatric patients regarding whether pneumoperitoneum affects cerebral oxygenation although end-tidal CO2 concentration remains normal. Therefore, this study was designed to evaluate the changes of cerebral oxygen saturation using near-infrared spectroscope during laparoscopic surgery in children. MethodsThe study comprised forty children who were scheduled for laparoscopic (Group L, n=20) or open (Group O, n=20) appendectomy. Hemodynamic variables, right and left regional cerebral oxygen saturation (RrSO2 and LrSO2), fraction of inspired oxygen, end-tidal carbon dioxide pressure (PETCO2), peak inspiratory pressure (Ppeak), respiratory minute volume, inspiratory and end-tidal concentrations of sevoflurane and body temperature were recorded. All parameters were recorded after anesthesia induction and before start of surgery (T0, baseline), 15min after start of surgery (T1), 30min after start of surgery (T2), 45min after start of surgery (T3), 60min after start of surgery (T4) and end of the surgery (T5). ResultsThere were progressive decreases in both RrSO2 and LrSO2 levels in both groups, which were not statistically significant at T1, T2, T3, T4. The RrSO2 levels of Group L at T5 were significantly lower than that of Group O. One patient in Group L had an rSO2 value <80% of the baseline value. ConclusionsCarbon dioxide insufflation during pneumoperitoneum in pediatric patients may not affect cerebral oxygenation under laparoscopic surgery.