Mean Cerebral Oxygen Saturation Research Articles

Cerebral oximetry index indicates delirium or stroke after carotid endarterectomy: An observational study.

The cerebral oximetry index (COx) uses near-infrared spectroscopy to estimate cerebral autoregulation during cardiac surgery. However, the relationship between intraoperative loss of cerebral autoregulation and postoperative delirium or stroke remains unclear in patients recovering from carotid endarterectomy (CEA). Our prospective observational cohort study enrolled patients scheduled for CEA. COx was estimated as the coefficient of a continuous, moving Spearman correlation between mean arterial pressure and cerebral oxygen saturation. A receiver operating characteristics curve with Youden's index identified the optimal COx threshold for predicting a composite of postoperative delirium or new-onset overt stroke. One hundred and forty patients scheduled for CEA were enrolled. The incidence of delirium was 10.7% (15/140) and the incidence of stroke was 3.6% (5/140), including 1 patient who had both. The cumulative anesthesia time when COx exceeded 0.3 was longer in patients with complications than those without. When COx>0.6, the corresponding predictive ability was AUC=0.69, Youden index=0.61, P=0.0003, with a positive predictive value of 100%. In the post hoc subgroup analyses, before clamping, the greatest increase in the risk was observed when COx>0.7 for 20min (Odds ratio=3.10, 95% CI 2.20, 3.78). In contrast, COx was not predictive during clamping. After clamping, the optimal COx threshold was 0.4 (AUC=0.85, Youden index=0.82, P<0.0001), with the positive predictive value being 100%. COx is a promising metric for predicting postoperative delirium or new-onset overt stroke in patients having CEA. The optimal COx threshold was 0.7 in the pre-clamping phase and 0.4 in the post-clamping phase.

Association between time-dependent changes in cerebrovascular autoregulation after cardiac arrest and outcomes: A prospective cohort study

This prospective observational single-center cohort study aimed to determine an association between cerebrovascular autoregulation (CVAR) and outcomes in hypoxic-ischemic brain injury post-cardiac arrest (CA), and assessed 100 consecutive post-CA patients in Japan between June 2017 and May 2020 who experienced a return of spontaneous circulation. Continuous monitoring was performed for 96 h to determine CVAR presence. A moving Pearson correlation coefficient was calculated from the mean arterial pressure and cerebral regional oxygen saturation. The association between CVAR and outcomes was evaluated using the Cox proportional hazard model; non-CVAR time percent was the time-dependent, age-adjusted covariate. The non-linear effect of target temperature management (TTM) was assessed using a restricted cubic spline. Of the 100 participants, CVAR was detected using the cerebral performance category (CPC) in all patients with a good neurological outcome (CPC 1–2) and in 65 patients (88%) with a poor outcome (CPC 3–5). Survival probability decreased significantly with increasing non-CVAR time percent. The TTM versus the non-TTM group had a significantly lower probability of a poor neurological outcome at 6 months with a non-CVAR time of 18%–37% (p < 0.05). Longer non-CVAR time may be associated with significantly increased mortality in hypoxic-ischemic brain injury post-CA.

Cerebral Autoregulation Status in Relation to Brain Injury on Electroencephalogram and Magnetic Resonance Imaging in Children Following Cardiac Surgery.

Background Disturbed cerebral autoregulation has been reported in children with congenital heart disease before and during cardiopulmonary bypass surgery, but not after. We sought to characterize the cerebral autoregulation status in the early postoperative period in relation to perioperative variables and brain injuries. Methods and Results A prospective and observational study was conducted in 80 patients in the first 48 hours following cardiac surgery. Cerebral oximetry/pressure index (COPI) was retrospectively calculated as a moving linear correlation coefficient between mean arterial blood pressure and cerebral oxygen saturation. Disturbed autoregulation was defined as COPI >0.3. Correlations of COPI with demographic and perioperative variables as well as brain injuries on electroencephalogram and magnetic resonance imaging and early outcomes were analyzed. Thirty-six (45%) patients had periods of abnormal COPI for 7.81 hours (3.38 hours) either at hypotension (median <45 mm Hg) or hypertension (median >90 mm Hg) or both. Overall, COPI became significantly lower over time, suggesting improved autoregulatory status during the 48 postoperative hours. All of the demographic and perioperative variables were significantly associated with COPI, which in turn was associated with the degree of brain injuries and early outcomes. Conclusions Children with congenital heart disease following cardiac surgery often have disturbed autoregulation. Cerebral autoregulation is at least partly the underlying mechanism of brain injury in those children. Careful clinical management to manipulate the related and modifiable factors, particularly arterial blood pressure, may help to maintain adequate cerebral perfusion and reduce brain injury early after cardiopulmonary bypass surgery. Further studies are warranted to determine the significance of impaired cerebral autoregulation in relation to long-term neurodevelopment outcomes.

Higher mean cerebral oxygen saturation shortly after extracorporeal cardiopulmonary resuscitation in patients who regain consciousness.

In cardiac arrest, cerebral ischemia and reperfusion injury mainly determine the neurological outcome. The aim of this study was to investigate the relation between the course of cerebral oxygenation and regain of consciousness in patients treated with extracorporeal cardiopulmonary resuscitation (ECPR). We hypothesized that rapid cerebral oxygenation increase causes unfavorable outcomes. This prospective observational study was conducted in three European hospitals. We included adult ECPR patients between October 2018 and March 2020, in whom cerebral regional oxygen saturation (rSO2 ) measurements were started minutes before ECPR initiation until 3 h after. The primary outcome was regain of consciousness, defined as following commands, analyzed using binary logistic regression. The sample consisted of 26 ECPR patients (23% women, Agemean 46 years). We found no significant differences in rSO2 values at baseline (49.1% versus 49.3% for regain versus no regain of consciousness). Mean cerebral rSO2 values in the first 30 min after ECPR initiation were higher in patients who regained consciousness (38%) than in patients who did not regain consciousness (62%, odds ratio 1.23, 95% confidence interval 1.01-1.50). Higher mean cerebral rSO2 values in the first 30 min after initiation of ECPR were found in patients who regained consciousness.

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.

Real-Time Evaluation of Cerebral Autoregulation Based on Near-Infrared Spectroscopy to Predict Clinical Outcome after Bypass Surgery in Moyamoya Disease.

Impaired cerebral autoregulation (CA) can cause negative outcomes in neurological conditions. Real-time CA monitoring can predict and thereby help prevent postoperative complications for neurosurgery patients, especially those suffering from moyamoya disease (MMD). We applied the concept of moving average to the correlation between mean arterial blood pressure (MBP) and cerebral oxygen saturation (SCO2) to monitor CA in real time, revealing optimal window size for the moving average. The experiment was conducted with 68 surgical vital-sign records containing MBP and SCO2. To evaluate CA, the cerebral oximetry index (COx) and coherence obtained from transfer function analysis (TFA) were calculated and compared between patients with postoperative infarction and those who without. For real-time monitoring, the moving average was applied to COx and coherence to determine the differences between groups, and the optimal moving-average window size was identified. The average COx and coherence within the very-low-frequency (VLF) range (0.02-0.07 Hz) during the entire surgery were significantly different between the groups (COx: AUROC = 0.78, p = 0.003; coherence: AUROC = 0.69, p = 0.029). For the case of real-time monitoring, COx showed a reasonable performance (AUROC > 0.74) with moving-average window sizes larger than 30 minutes. Coherence showed an AUROC > 0.7 for time windows of up to 60 minutes; however, for windows larger than this threshold, the performance became unstable. With an appropriate window size, COx showed stable performance as a predictor of postoperative infarction in MMD patients.

Relationship Between Cerebral Hemodynamics, Tissue Oxygen Saturation, and Delirium in Patients With Septic Shock: A Pilot Observational Cohort Study.

Background: Septic shock patients have tendencies toward impairment in cerebral autoregulation and imbalanced cerebral oxygen metabolism. Tissue Oxygen Saturation (StO2) and Transcranial Doppler (TCD) monitoring were undertaken to observe the variations of cerebral hemodynamic indices and cerebral/peripheral StO2 to find risk factors that increase the sepsis-associated delirium (SAD).Materials and Methods: The research cohort was chosen from septic shock patients received in the Department of Critical Care Medicine, Xiangya Hospital, Central South University between May 2018 and March 2019. These patients were separated into two groups, SAD and non-SAD as assessed by using the Confusion Assessment Method for the Intensive Care Unit (CAM-ICU). Comparisons were made between the two groups in terms of peripheral StO2, fluctuations in regional cerebral oxygen saturation (rSO2), cerebral vascular automatic regulation function [Transient Hyperemic Response Ratio (THRR) index], cerebral hemodynamic index, organ function indicators, blood gas analysis indices, and patient characteristics.Results: About 39% of the patients (20/51) suffered from SAD. Nearly 43% of the patients died within 28 days of admission (22/51). Individuals in the SAD cohort needed a longer period of mechanical ventilation [5 (95% CI 2, 6) vs. 1 days (95% CI 1, 4), p = 0.015] and more time in ICU [9 (95% CI 5, 20) vs. 5 days (95% CI 3, 9), p = 0.042]; they also experienced more deaths over the 28-day period (65 vs. 29%, p = 0.011). The multivariate regression analysis indicated that independent variables associated with SAD were THRR index [odds ratio (OR) = 5.770, 95% CI: 1.222–27.255; p = 0.027] and the mean value for rSO2 was < 55% (OR = 3.864, 95% CI: 1.026–14.550; p = 0.046).Conclusion: Independent risk factors for SAD were mean cerebral oxygen saturation below 55% and cerebrovascular dysregulation (THRR < 1.09).

Comparison of the effects of normal and low blood pressure regulation on the optic nerve sheath diameter in robot assisted laparoscopic radical prostatectomy.

BackgroundRobot-assisted laparoscopic radical prostatectomy is an advanced and popular surgical technique. However, increased intracranial pressure which is caused by CO2 pneumoperitoneum and Trendelenburg position is the main cerebrovascular effect. Measurement of optic nerve sheath diameter using ocular ultrasound is a noninvasive and reliable method for the assessment of intracranial pressure. The primary endpoint of this study was to identify whether low blood pressure regulation has any benefit in attenuating an increase of optic nerve sheath diameter during robot-assisted laparoscopic radical prostatectomy.MethodsOptic nerve sheath diameter and cerebral oxygen saturation were measured at baseline (supine position), one and two hours after pneumoperitoneum and Trendelenburg position respectively, and after return to supine position in normal (n = 27) and low blood pressure groups (n = 24).ResultsMean optic nerve sheath diameter values measured at one and two hours after pneumoperitoneum and Trendelenburg position were significantly increased compared to the baseline value (P < 0.001 in normal blood pressure group; P = 0.003 in low blood pressure group). However, the mean optic nerve sheath diameter and cerebral oxygen saturation measured at any of the time points as well as degrees of change between the two groups did not show any significant changes. The peak values of optic nerve sheath diameter in normal and low blood pressure groups demonstrated 14.9% and 9.2% increases, respectively.ConclusionsLow blood pressure group demonstrated an effect in maintaining an increase of optic nerve sheath diameter less than 10% during CO2 pneumoperitoneum and Trendelenburg position.

Cerebral autoregulation in infants during sevoflurane anesthesia for craniofacial surgery.

Data on cerebral pressure-flow autoregulation in the youngest children are scarce. We studied the correlation between mean arterial pressure and cerebral tissue oxygen saturation (rSO2 ) by near-infrared spectroscopy (NIRS) in patients undergoing nose, lip, and palate surgery. We tested the hypothesis that cerebral pressure-flow autoregulation is impaired in children less than 1year undergoing surgery and general anesthesia with sevoflurane under controlled mechanical ventilation. After approval from the Ethical board, 15 children aged <1year were included. Before anesthesia induction, a NIRS sensor (INVOSTM , Medtronic, Minneapolis, USA) was placed over the cerebral frontal lobe. Frontal rSO2 , a surrogate for cerebral perfusion, mean arterial pressure, end-tidal CO2 - and sevoflurane concentration, and arterial oxygen saturation were sampled every minute after the induction. A repeated measures correlation analysis was performed to study correlation between mean arterial pressure and cerebral rSO2 , and the repeated measures correlation coefficient (rrm ) was calculated. Fifteen patients, aged 7.7±1.9months, were studied. rSO2 showed a positive correlation with mean arterial pressure ([95% CI: 9.0-12.1], P<0.001) with a moderate to large effect size (rrm =0.462), indicating an impaired cerebral pressure-flow autoregulation. The slopes of the rSO2 -mean arterial pressure correlations were steeper in patients who were hypotensive (mean arterial pressure <50mm Hg) compared to patients having a mean arterial pressure ≥50mm Hg, indicating that at lower mean arterial pressure, the cerebral pressure dependence of cerebral oxygenation is even more pronounced. During sevoflurane anesthesia in the youngest pediatric patients, cerebral perfusion is pressure-dependent, suggesting that the efficiency of the cerebral blood flow autoregulation is limited.

Postoperative Cerebral Oxygen Saturation in Children After Congenital Cardiac Surgery and Long-Term Total Intelligence Quotient: A Prospective Observational Study.

During the early postoperative period, children with congenital heart disease can suffer from inadequate cerebral perfusion, with possible long-term neurocognitive consequences. Cerebral tissue oxygen saturation can be monitored noninvasively with near-infrared spectroscopy. In this prospective study, we hypothesized that reduced cerebral tissue oxygen saturation and increased intensity and duration of desaturation (defined as cerebral tissue oxygen saturation < 65%) during the early postoperative period, independently increase the probability of reduced total intelligence quotient, 2 years after admission to a PICU. Single-center, prospective study, performed between 2012 and 2015. The PICU of the University Hospitals Leuven, Belgium. The study included pediatric patients after surgery for congenital heart disease admitted to the PICU. None. Postoperative cerebral perfusion was characterized with the mean cerebral tissue oxygen saturation and dose of desaturation of the first 12 and 24 hours of cerebral tissue oxygen saturation monitoring. The independent association of postoperative mean cerebral tissue oxygen saturation and dose of desaturation with total intelligence quotient at 2-year follow-up was evaluated with a Bayesian linear regression model adjusted for known confounders. According to a noninformative prior, reduced mean cerebral tissue oxygen saturation during the first 12 hours of monitoring results in a loss of intelligence quotient points at 2 years, with a 90% probability (posterior β estimates [80% credible interval], 0.23 [0.04-0.41]). Similarly, increased dose of cerebral tissue oxygen saturation desaturation would result in a loss of intelligence quotient points at 2 years with a 90% probability (posterior β estimates [80% credible interval], -0.009 [-0.016 to -0.001]). Increased dose of cerebral tissue oxygen saturation desaturation and reduced mean cerebral tissue oxygen saturation during the early postoperative period independently increase the probability of having a lower total intelligence quotient, 2 years after PICU admission.

Cerebral Oxygenation and Autoregulation in Preterm Infants (Early NIRS Study)

To determine if decreased cerebral oxygenation or altered cerebral autoregulation as measured by near-infrared spectroscopy (NIRS) in the first 96 postnatal hours is associated with an increased risk of death or severe neuroradiographic abnormalities in very preterm infants. The Early NIRS prospective, multicenter study enrolled very preterm infants with a birth weight of <1250g from 6 tertiary neonatal intensive care units. Mean arterial blood pressure and cerebral oxygen saturation (Csat) were continuously monitored using a neonatal sensor until 96hours of age. Moving window correlations between Csat and mean arterial blood pressure determined time periods with altered cerebral autoregulation, and percentiles of correlation were compared between infants with and without the adverse outcome of mortality or severe neuroradiographic abnormalities by early cranial ultrasound. Of 103 subjects with mean gestational age of 26weeks, 21 (20%) died or had severe neuroradiographic abnormalities. Infants with adverse outcomes had a lower mean Csat (67±9%) compared with those without adverse outcomes (72±7%; P=.02). A Csat of <50% was identified as a cut-point for identifying infants with adverse outcome (area under the curve, 0.76). Infants with adverse outcomes were more likely to have significant positive or negative correlations between Csat and mean arterial blood pressure, indicating impaired cerebral autoregulation (P=.006). Early NIRS monitoring may detect periods of lower cerebral oxygenation and altered cerebral autoregulation, identifying preterm infants at risk for mortality or neuroradiographic injury. An improved understanding of the relationship between altered hemodynamics and cerebral oxygenation may inform future strategies to prevent brain injury.

Cerebral Hemodynamic Profile in Ischemic and Hemorrhagic Brain Injury Acquired During Pediatric Extracorporeal Membrane Oxygenation.

To describe the cerebral hemodynamic profiles associated with ischemic and hemorrhagic brain injury during neonatal and pediatric extracorporeal membrane oxygenation. A retrospective cohort study. Tertiary PICU. Forty-seven neonatal and pediatric patients (0-15 yr of age) placed on extracorporeal membrane oxygenation from January 2014 to December 2018. Continuous monitoring of mean arterial pressure and cerebral tissue oxygen saturation was conducted through entire extracorporeal membrane oxygenation run. Wavelet analysis was performed to assess changes in cerebral autoregulation and to derive pressure-dependent autoregulation curves based on the mean arterial pressure and cerebral tissue oxygen saturation data. Patients were classified into three brain injury groups: no-injury, ischemic injury, and hemorrhagic injury based on neuroimaging results. No-injury patients (n = 23) had minimal variability in the autoregulation curve over a broad range of blood pressure. Ischemic injury (n = 16) was more common than hemorrhagic injury (n = 8), and the former was associated with increased mortality and morbidity. Ischemic group showed significant abnormalities in cerebral autoregulation in the lower blood pressure range, suggesting pressure-dependent cerebral perfusion. Hemorrhagic group had highest average blood pressure as well as the lowest cerebral tissue oxygenation saturation, suggesting elevated cerebral vascular resistance. Mean heparin dose during extracorporeal membrane oxygenation was lower in both ischemic and hemorrhagic groups compared with the no-injury group. This study outlines distinct differences in underlying cerebral hemodynamics associated with ischemic and hemorrhagic brain injury acquired during extracorporeal membrane oxygenation. Real-time monitoring of cerebral hemodynamics in patients acquiring brain injury during extracorporeal membrane oxygenation can help optimize their management.

A method for modelling the oxyhaemoglobin dissociation curve at the level of the cerebral capillary in humans.

What is the central question of this study? Can the change in haemoglobin's affinity for oxygen in the human cerebral circulation be modelled in vivo? What is the main finding and its importance? We provide a novel method for modelling the oxyhaemoglobin dissociation curve at the cerebral capillary level in humans, so that the cerebral capillary and mitochondrial oxygen tensions can reliably be estimated. This may be useful in future human-experimental studies on cerebral oxygen transport. We provide a method for modelling the oxyhaemoglobin dissociation curve (ODC) in the cerebral capillary in humans. In contrast to most previous approaches, our method involves the construction of an averaged ODC based on paired arterial-jugular venous blood gas values, which enables the estimation of oxygen parameters in cerebral capillary blood. The method was used to determine the mean cerebral capillary oxygen saturation and tension from data previously collected from 30 healthy volunteers. The averaged ODC provided systematically higher capillary oxygen tensions than when assuming a 'fixed' standard arterial ODC. When the averaged and measured arterial ODC were used for constructing the capillary ODC, similar values were obtained during resting breathing, but not when the arterial ODC was modulated by hypocapnia. The findings suggest that our method for modelling the cerebral capillary ODC provides robust and physiologically reliable estimates of the cerebral capillary oxygen tension, which may be of use in future studies of cerebral oxygen transport in humans.

Antenatal Magnesium Sulfate and Preeclampsia Differentially Affect Neonatal Cerebral Oxygenation

Introduction: Magnesium sulfate (MgSO₄) is frequently administered for maternal and fetal neuroprotection in preeclampsia (PE) and imminent preterm birth, respectively. Objective: To assess whether MgSO₄ affects neonatal cerebral oxygenation, blood flow, and cerebral autoregulation (CAR) during the first postnatal days independently from PE. Methods: 148 neonates <32 weeks gestational age were included. Cerebral fractional tissue oxygen extraction (cFTOE) was extracted from a daily 2-h period, during which peak systolic blood flow velocity (PSV) and resistance index (RI) of the pericallosal artery were obtained. The percent time of impaired CAR (correlation coefficient between mean arterial blood pressure and cerebral oxygen saturation >0.5) was determined. Linear mixed models were applied. Results: MgSO₄ exposure was recorded in 77 neonates. Twenty-nine neonates were born following PE. MgSO₄ independently lowered cFTOE (B: –0.026, 95% CI: –0.050 to 0.002, p < 0.05) but did not affect PSV and RI. PE was associated with a lower cFTOE (B: –0.041, 95% CI: –0.067 to –0.015, p < 0.05) and a tendency towards both lower PSV (B: –4.285, 95% CI: –9.067 to 0.497, p < 0.1) and more impaired CAR (B: 4.042, 95% CI: –0.028 to 8.112, p < 0.1), which seemed to be strongly mediated by fetal brain sparing. MgSO₄ did not alter CAR. Conclusions: In contrast to fetal brain sparing in PE, MgSO₄ seems to lower cFTOE by lowering cerebral oxygen demands in preterm neonates without affecting the cerebrovasculature.

The effects of anaesthesia induction with propofol or ketofol on cerebral oxygenation in patients above 60 years of age

Side effects such as hypotension and cerebral perfusion disorder may be encountered after anaesthesia induction, especially in elderly patients. Some studies have attempted to determine whether hypotension during induction and associated organ perfusion disorders can be prevented when propofol is used in combination with ketamine. However, no study has come to light investigating the effects of ketamine added to propofol on cerebral oximetry. The present study aimed to compare the effects of anaesthesia induction with propofol or propofol+ketamine (ketofol) on haemodynamic changes and cerebral oximetry in elderly patients undergoing anaesthesia induction. A total of 40 patients were randomly divided into two groups. Cerebral oximetry sensors were placed in the right and left of the frontal region. Patients in Group P were treated with 1.5 mg/kg propofol IV induction and patients in Group K were treated with the 0.2 ml/kg ketofol IV. The patients in both groups received 0.5 mg/kg lidocaine, 0.6 mg/kg rocuronium and a 0.1 mcg/kg/min infusion of remifentanil. Heart rate (HR), systolic, diastolic and mean arterial pressure (SBP, DBP, MAP) and cerebral oxygen saturation (RSO2) values before and 1, 3, 5, 10, 30 and 60 minutes after induction were recorded.SBP, DBP and MAP values were significantly lower in the propofol group at 1, 3 and 5 minutes after induction (p < 0.05). The right-side RSO2 values were significantly lower at 3 and 5 minutes after induction in the propofol group compared to the ketofol group and the left-side RSO2 values were similarly significantly lower after 1, 3 and 5 minutes (p < 0.05). Ketofol used in anaesthesia induction has less effect than propofol on mean arterial pressure and cerebral oxygen saturation values. Therefore, ketofol appears to be a good choice for use in anaesthesia induction in elderly patients.

Perioperative Assessment of Cerebral Oxygen Metabolism in Infants With Functionally Univentricular Hearts Undergoing the Bidirectional Cavopulmonary Connection.

The transition from single-ventricle lesions with surgically placed systemic-to-pulmonary artery shunt to the circulation following a bidirectional cavopulmonary connection results in higher pressure in the superior vena cava when compared with the preceding circulation. The aim of this study was to evaluate the impact of this transition on the perioperative cerebral oxygen metabolism. Prospective observational cohort study. Pediatric critical care unit of a tertiary referral center. Sixteen infants after bidirectional cavopulmonary connection. Cardiac surgery (bidirectional cavopulmonary connection). We measured regional cerebral oxygen saturation, amount of hemoglobin, blood flow velocity, and microperfusion immediately before, 12-24 hours, and 36-48 hours following bidirectional cavopulmonary connection. Based on these measurements, we calculated cerebral fractional tissue oxygen extraction and approximated cerebral metabolic rate of oxygen. Mean pressure in the superior vena cava increased significantly (8 vs 17 mm Hg; p < 0.001) following bidirectional cavopulmonary connection. Mean cerebral oxygen saturation increased from 49.0% (27.4-61.0) to 56.9% (39.5-64.0) (p = 0.008), whereas mean cerebral blood flow velocity decreased from 80.0 arbitrary units (61.9-93.0) to 67.3 arbitrary units (59.0-83.3) (p < 0.001). No change was found in the cerebral amount of hemoglobin and in the cerebral microperfusion. Mean cerebral fractional tissue oxygen extraction (0.48 [0.17-0.63] vs 0.30 [0.19-0.56]; p = 0.006) and approximated cerebral metabolic rate of oxygen (5.82 arbitrary units [2.70-8.78] vs 2.27 arbitrary units [1.19-7.35]; p < 0.001) decreased significantly. Establishment of bidirectional cavopulmonary connection is associated with postoperative improvement in cerebral oxygen metabolism. Cerebral amount of hemoglobin did not increase, although creation of the bidirectional cavopulmonary connection results in significant elevation in superior vena cava pressure. Improvement in cerebral oxygen metabolism was due to lower cerebral blood flow velocity and stable microperfusion, which may indicate intact cerebral autoregulation.

Effects of Closed Endotracheal Suctioning on Systemic and Cerebral Oxygenation and Hemodynamics in Children.

To evaluate the effects of closed endotracheal tube suctioning on systemic oxygen saturation, cerebral regional oxygen saturation, and somatic regional (renal) oxygen saturation and hemodynamic variables in children. Prospective observational. A tertiary care PICU. Children aged 0-18 years, requiring invasive mechanical ventilation and with an arterial line. Closed endotracheal suction. The study included 19 sedated and intubated children, 0-18 years old. They were enrolled in an ongoing prospective observational study. We used near-infrared spectroscopy for cerebral regional oxygen saturation and somatic regional (renal) oxygen saturation. The timing of each closed endotracheal tube suctioning event was accurately identified from video recordings. We extracted systemic oxygen saturation, cerebral regional oxygen saturation, somatic regional (renal) oxygen saturation, heart rate, and systolic blood pressure and diastolic blood pressure for 5 minutes before and 5 minutes after each event and used these data for analysis. One-minute average values of these variables were used for repeated-measures analysis. We analyzed 287 endotracheal tube suctioning episodes in 19 children. Saline was instilled into the endotracheal tube during 61 episodes. The mean heart rate (107.0 ± 18.7 vs 110.2 ± 10.4; p < 0.05), mean arterial blood pressure (81.5 ± 16.1 vs 83.0 ± 15.6 mm Hg; p < 0.05), and the mean cerebral regional oxygen saturation (64.8 ± 8.3 vs 65.8 ± 8.3; p < 0.05) were increased after suctioning. The mean systemic oxygen saturation (96.9 ± 2.7 vs 96.7 ± 2.7; p = 0.013) was decreased, whereas the mean somatic regional (renal) oxygen saturation was not significantly different after endotracheal tube suctioning. Repeated-measures analysis revealed transient increases in heart rate, respiratory rate, systolic blood pressure, and diastolic blood pressure; a sustained increase in cerebral regional oxygen saturation; and transient decreases in systemic oxygen saturation and somatic regional (renal) oxygen saturation. Saline instillation did not affect oxygenation or hemodynamic variables. Closed endotracheal tube suctioning in sedated children is associated with transient but clinically insignificant changes in heart rate, blood pressure, cerebral regional oxygen saturation, systemic oxygen saturation, and somatic regional (renal) oxygen saturation. Saline instillation during endotracheal tube suctioning had no adverse effects on systemic or cerebral oxygenation.

Impairment of cerebral autoregulation in pediatric extracorporeal membrane oxygenation associated with neuroimaging abnormalities.

.Extracorporeal membrane oxygenation (ECMO) is a life-supporting therapy for critically ill patients with severe respiratory and/or cardiovascular failure. Cerebrovascular impairment can result in hemorrhagic and ischemic complications commonly seen in the patients supported on ECMO. We investigated the degree of cerebral autoregulation impairment during ECMO as well as whether it is predictive of neuroimaging abnormalities. Spontaneous fluctuations of mean arterial pressure (MAP) and cerebral tissue oxygen saturation () were continuously measured during the ECMO run. The dynamic relationship between the MAP and fluctuations was assessed based on wavelet transform coherence (WTC). Neuroimaging was conducted during and/or after ECMO as standard of care, and the abnormalities were evaluated based on a scoring system that had been previously validated among ECMO patients. Of the 25 patients, 8 (32%) had normal neuroimaging, 7 (28%) had mild to moderate neuroimaging abnormalities, and the other 10 (40%) had severe neuroimaging abnormalities. The degrees of cerebral autoregulation impairment quantified based on WTC showed significant correlations with the neuroimaging scores (; ). Evidence that cerebral autoregulation impairment during ECMO was related to the patients’ neurological outcomes was provided.

Does the degree of beach chair position during shoulder arthroscopy affect cerebral oxygenation? A prospective comparative study

Background: The aim of this prospective cohort study was to determine the incidence of cerebral desaturation events (CDE) in patients undergoing shoulder arthroscopy in the beach chair position (BCP) compared to patients undergoing shoulder arthroscopy in the semi-upright sitting position (SSP). Methods: This prospective study included 220 patients, 150 men (68.18%) and 70 women (31.82%). The average age was 46 yr (24-68) years. Patients under 18 yr of age, those with uncontrolled diabetes, a previous cerebral stroke, a myocardial infarction, rheumatoid arthritis, congestive heart failure, severe cervical disc prolapsed, or severe obesity (body mass index &gt;30) were excluded from the study. The patients were divided into two groups (110 patients in each group). Group A patients had shoulder arthroscopy done in the 60-degree beach chair position and Group B had shoulder arthroscopy done in a semi-upright sitting position at 90 degrees. Mean arterial blood pressure and cerebral oxygen saturation were measured at different stages: before induction of anesthesia (T0), after induction (T1 [baseline]), after positioning (T2), after induction of hypotension (T3), and 1 hr after final position (T4). Cerebral desaturation was defined as a reduction in regional cerebral oxygen saturation to less than 80% of baseline value for 15 sec or longer. Each stage was compared with others in the same group and with the other group. Results: In both groups, the mean arterial blood pressure (MAP) values at T2 were significantly lower than at T1. The MAP values at T3 and T4 were significantly lower than those at T1 and T2. There was a significant decrease in regional cerebral oxygen saturation in stage T3 when compared to previous stages in the same group. Without any significant decrease in stage T4 compared to T3 in the same group. We found no significant difference in regional cerebral oxygen saturation when comparing each stage in both groups. Conclusions: No significant difference was noted in regional cerebral oxygen saturation between patients operated on in the beach chair position and those operated on in the semi-upright sitting position. A direct relation was noted between the decrease in mean arterial pressure and decrease in cerebral oxygen saturation.

The relationship between the Trendelenburg position and cerebral hypoxia inpatients who have undergone robot-assisted hysterectomy and prostatectomy

Background/aim: This study aimed to evaluate the relationship between the Trendelenburg position and cerebral hypoxia in robot-assisted hysterectomy and prostatectomy.Materials and methods: A standardized mini-mental state examination was administered to 50 patients enrolled in the study 1 h before and after surgery. Near infrared spectroscopy (NIRS) values and hemodynamic and respiratory parameters were recorded after induction of anesthesia (baseline) and once every 20 min in the Trendelenburg position and supine positions. The relationship between the development of cerebral desaturation and the patient's position was examined. Results: For all patients, the baseline mean cerebral oxygen saturation (RSO2) on the right and left were 70.5 ± 7.3% and 70.6 ± 6.7%, respectively. Right RSO2 values at 20 min and 60 min in the Trendelenburg position decreased significantly, but they increased at 120 min. A significant positive correlation was found between right RSO2 and EtCO2 in the supine period following surgery, and between left RSO2 and EtCO2 at 60 min in the Trendelenburg and supine positions. The relationship between NIRS values and cognitive dysfunction was not significant.Conclusion: We found that cerebral saturation decreases as age increases, and cerebral desaturation may occur owing to the Trendelenburg position. There was no correlation between patients? cognitive function and NIRS values.