Changes In rSO2 Research Articles

Study on cerebral oxygen saturation in children with sleep-disordered breathing.

To explore the association between the severity of sleep-disordered breathing, different types of respiratory events, peripheral oxygen saturation (SpO2), age and sleep stage on cerebral oxygen saturation (rSO2) in children. We enrolled children aged 4-14 years who were treated for snoring or mouth breathing at the Sleep Center of Beijing Children's Hospital, from February 2022 to July 2022. All children completed polysomnography, and SpO2, rSO2, and heart rate (HR) were recorded synchronously. A total of 70 children were included, including 16 (22.9%) with primary snoring, 38 (54.3%) with mild obstructive sleep apnea (OSA), and 16 (22.9%) with moderate-to-severe OSA. There were no significant differences in the mean rSO2 or minimum rSO2 among the primary snoring, mild OSA, and moderate-to-severe OSA groups (all p > 0.05). A total of 1119 respiratory events were included in the analysis. Regardless of the type of respiratory event, rSO2 and HR changes occur prior to fluctuations in SpO2. A mixed-effects model showed that ΔrSO2 was positively correlated with ΔSpO2, duration of respiratory event, mixed and obstructive apnea, central apnea, while negatively correlated with age and rapid eye movement (REM) sleep stage (all p < 0.05). Larger rSO2 fluctuations were impacted by a greater ΔSpO2, longer duration of respiratory events, younger age, apnea-related respiratory events and non-REM sleep stage. Thus, sleep disordered breathing in younger children warrants more attention. More research is needed to determine whether REM sleep has special protective effects on rSO2.

Comparison of Changes in Rso2 in Midazolam and Propofol Sedation Post Craniotomy in the Icu of H. Adam Malik Hospital

Introduction: Cerebral oxygen saturation reflects tissue perfusion in the cerebrum. Decreases in cerebral oxygen saturation are linked to longer hospital stays and cognitive impairment. Midazolam and propofol can decrease cerebral blood flow through decreasing the cerebral oxygen metabolic rate. The purpose of this research is to analyze the comparison of changes in cerebral oxygen saturation after midazolam and propofol administration in post-craniotomy patients in the ICU of Haji Adam Malik General Hospital Medan. Subject and Method: This is a randomized control trial study. Patients were divided into, Midazolam group, that given an initial dose of 0.05 mg/kg followed by a maintenance dose of 0.02-0.10 mg/kg/hour and Propofol group that given sedation with a dose of 0.3-3mg/kg/hour, with the target of the 2 groups being a Richmond Agitation-Sedation Scale (RASS) value of 0 to -2. Data analysis using unpaired T test. Results: The results for cerebral regional oxygen saturation and RASS between groups showed significant differences in right and left value (p &lt; 0.001), but there was no significant difference in RASS (p&gt;0.05) between each group at each measurement time. The results of the analysis of cerebral regional oxygen saturation and RASS between times, there was no significant difference in right and left value (p&gt;0.05), but there was a significant difference in RASS (p&lt;0.001) at each measurement time. Based on the results of the analysis carried out, it is known that there is no statistically significant difference in changes in cerebral regional oxygen saturation both right and left in changes in RASS because it is found that all data have p&gt;0.05. Conclusion: There is no change in right and left for cerebral regional oxygen saturation after administration of propofol and midazolam groups with RASS value 0 to -2 in post-craniotomy patients in the ICU of Haji Adam Malik General Hospital Medan

Effects to cerebral oxygenation by arteriovenous fistula creation in patients with chronic kidney disease.

Vascular access, including arteriovenous fistula (AVF), is essential in patients undergoing hemodialysis (HD). However, the presence of AVF is non-physiological in humans and could pose a burden to the systemic circulation or tissue microcirculation, potentially affecting tissue oxygenation, including in the brain. Recently, near-infrared spectroscopy has been used to measure regional oxygen saturation (rSO2) as a marker of cerebral oxygenation in various settings, including in patients undergoing HD. Thus far, no studies have reported changes in cerebral rSO2 before and after AVF creation. This study aimed to monitor the differences in cerebral oxygenation before and after AVF creation and to clarify the clinical factors affecting the changes in cerebral rSO2. Forty-eight patients (34 men, 14 women) with chronic kidney disease (CKD) who were not undergoing dialysis and newly created AVF were recruited. Cerebral rSO2 values before and after AVF creation were evaluated using near-infrared spectroscopy (INVOS 5100c). Cerebral rSO2 values were significantly changed from 60.3% ± 7.5% to 58.4% ± 6.8% before and after AVF creation in all patients (p < 0.001). Cerebral rSO2 were also lower in patients with diabetes mellitus (DM) than in those without DM (57.5 ± 7.1 vs 63.7 ± 6.5, p = 0.003) before surgery; however, no differences of changes in cerebral rSO2 were observed between the two groups after AVF creation. Additionally, multivariate regression analysis identified changes in HR (standardized coefficient: 0.436) as independent factors associated with changes in cerebral rSO2. Surgically created AVF was associated with the deterioration of cerebral rSO2 in patients with CKD not undergoing dialysis. Notably, AVF could cause cerebral hypoxia, and thus further studies are needed to clarify the clinical factors influencing changes in cerebral oxygenation after AVF creation.

#1806 Cycling is safe – effect of intradialytic cycle ergometry on cerebral oxygenation and cognitive function – a pilot study

Abstract Background and Aims Patients on chronic hemodialysis benefit from intradialytic exercise with improvements in endurance, muscle strength and health-related quality of life. It is not known whether the increased oxygen demand during intradialytic exercise negatively affects cerebral oxygenation and cerebral function. The aim of the study was to assess the risk of cerebral undersupply by measuring cerebral oxygenation, perfusion and cognitive function during and after intradialytic ergometer training. Method Twelve patience on maintenance hemodialysis (HD) trice weekly were included in the study. In an initial ramp test, using bed cycle ergometer, we first determined the maximum physical strength (Pmax) at the level of exhaustion (HD A). Then, one hour after start of a second HD (HD B), patients performed 40%, 50% and 60% of Pmax for 6 min. Pulmonary function tests, blood volume (BVM), cardiac output (by electrical cardiometry), regional cerebral oxygen saturation (rSO2) (by near-infrared spectroscopy) and cerebral blood flow (CBF, by Doppler sonography) were measured. The relative changes in rSO2, CBF and hematocrit were used to calculate cerebral oxygen supply (DO2). Cognitive tests (Stroop, Trail Making and Mini Addenbrookes Cognitive Examination Test) were performed before and after HD sessions with and, as controls, without ergometry (HD-C). Results Median age was 68 (42-85) years, 9/12 were male, complete data set was obtained in 10 patients. During step test exercise (HD B), at the highest exercise level (according to Borg (1-10) 6.75 ± 2.9), rSO2 increased (+6 ± 9%, p=0.034) without a significant change in CBF. In the meantime, relative blood volume decreased during ergometry (-5.8 ± 2.73%; p=0.002), causing a temporary increase of hematocrit. Despite a small decrease in CBF in 3 patients, the mean change of rSO2, CBF and hematocrit always had a positive trend in all patients, as a surrogate of stable cerebral oxygen supply (Table 1). In comparative cognitive tests (B vs. C), we observed no significant changes in cognitive functions. Conclusion In this pilot study, intradialytic bed-cycle ergometry during the first hour of HD for &amp;lt;20 min at 40-60% of patients’ individual maximum intensity had no negative effects on cerebral oxygenation and function. Specific studies testing the safety intradialytic exercise with different conditions, such as increasing intensity or duration, are needed.

Hepatic Oxygenation Changes and Symptomatic Intradialytic Hypotension.

Clinical studies on differences among changes in cerebral and hepatic oxygenation during hemodialysis (HD) in patients with and without intradialytic hypotension (IDH) are limited. We investigated changes in intradialytic cerebral and hepatic oxygenation before systolic blood pressure (SBP) reached the nadir during HD and compared these differences between patients with and without symptomatic IDH. We analyzed data from 109 patients with (n = 23) and without (n = 86) symptomatic IDH who were treated with HD. Cerebral and hepatic regional oxygen saturation (rSO2), as a marker of tissue oxygenation and circulation, was monitored during HD using an INVOS 5100c oxygen saturation monitor. Changes in cerebral or hepatic rSO2 when SBP reached the nadir during HD were compared between the groups of patients. The cerebral rSO2 before HD in patients with and without symptomatic IDH was 49.7 ± 11.2% and 51.3 ± 9.1% (p = 0.491). %Changes in cerebral rSO2 did not significantly differ between the two groups from 60 min before the SBP nadir during HD. Hepatic rSO2 before HD in patients with and without symptomatic IDH was 58.5 ± 15.4% and 57.8 ± 15.9% (p = 0.869). The %changes in hepatic rSO2 were significantly lower in patients with symptomatic IDH than in those without throughout the observational period (p &lt; 0.001). We calculated the area under the receiver operating characteristic curve (AUC) and estimated cutoff values for changes in hepatic rSO2 as a symptomatic IDH predictor. The predictive ability at 5 and 40 min before symptomatic IDH onset was excellent, with AUCs and cutoff values of 0.847 and 0.841, and -10.9% and -5.0%, respectively. Hepatic oxygenation significantly decreased more in patients with symptomatic IDH before its onset, than in those without symptomatic IDH, whereas changes in cerebral oxygenation did not differ. Evaluating changes in hepatic oxygenation during HD might help to predict symptomatic IDH.

The Effect of Intermittent Pneumatic Compression on Hemodynamics and Regional Cerebral Oxygen Saturation in Laparoscopic Bariatric Surgery with Mild Hypercapnia in the Steep Reverse Trendelenburg Position.

Obesity negatively affects hemodynamics and cerebral physiology. We investigated the effect of the utilization of an intermittent pneumatic compression (IPC) device on hemodynamics and cerebral physiology in patients undergoing laparoscopic bariatric surgery under general anesthesia with lung-protective ventilation. Sixty-four patients (body mass index > 30 kg/m2) were randomly assigned to groups that received an IPC device (IPC group, n = 32) and did not (control group, n = 32). The mean arterial pressure (MAP), heart rate (HR), need for vasopressors, cerebral oxygen saturation (rSO2), and cerebral desaturation events were recorded. The incidence of intraoperative hypotension was not significantly different between groups (p = 0.153). Changes in MAP and HR over time were similar between groups (p = 0.196 and p = 0.705, respectively). The incidence of intraoperative cerebral desaturation was not significantly different between groups (p = 0.488). Changes in rSO2 over time were similar between the two groups (p = 0.190) during pneumoperitoneum. Applying IPC to patients with obesity in the steep reverse Trendelenburg position may not improve hemodynamic parameters, vasopressor requirements, or rSO2 values during pneumoperitoneum under lung-protective ventilation. During laparoscopic bariatric surgery, IPC alone has limitations in improving hemodynamics and cerebral physiology.

Cerebral oxymetry in patients with ischemic stroke and concomitant obstructive sleep apnea syndrome

Cerebral stroke is an important medical and social problem of our time and the most common cause of permanent disability. In patients with brain damage due to ischemic stroke and concomitant obstructive sleep apnoea, numerous episodes of hypoventilation and apnoea cause significant «failures» in saturation and changes in cerebral perfusion, which negatively affects immediate and long-term treatment outcomes. Cerebral oximetry is widely used in clinical practice in various fields of surgery (cardiovascular, paediatric, neurosurgery, etc.), but its potential as a method of monitoring secondary brain damage and controlling treatment in patients with ischaemic cerebral stroke is poorly understood. Objective — to evaluate the effect of non-invasive CPAP support (Continuous Positive Airway Pressure — a method of non-invasive respiratory support in which positive pressure is created in the patient’s airways) on cerebral oximetry in the treatment of patients with ischaemic stroke and concomitant obstructive sleep apnoea syndrome. Materials and methods. Patients with verified mild to moderate ischaemic stroke underwent screening diagnostics to confirm the presence of obstructive sleep apnoea syndrome (SomnoChek micro, Weinman, Germany). We studied 60 patients with obstructive sleep apnoea in the setting of ischemic stroke, who were divided into two groups depending on the treatment method: control (n = 30), in which only conventional stroke treatment was used, and experimental (n = 30), in which the traditional treatment regimen and respiratory support (auto-SAPP) during night sleep with the ResMed Air Sencei apparatus (Australia) were used. To monitor the effectiveness of respiratory support, along with other methods of objective control, cerebral oximetry was used using the Masimo Root apparatus (Masimo, USA). The average rSO2 values on the side of the stroke-affected hemisphere were recorded at the following times: at the beginning of the study, on the 3rd, 5th and 7th day of treatment. The data obtained were processed statistically. Results. The initial average values of rSO2 of the affected by stroke hemisphere in patients of groups I and II were in the range of pathological values, and were (49.27 ± 4.98) and (50.60 ± 5.40) %, respectively, that is, the groups at the beginning of the study were compared to each other. It was found, that in group I patients statistically significant changes in rSO2 % in the intervals of the 1st and 3rd days, the 3rd and 5th days, and the 5th and 7th days — were not observed. Only during the 7th day of observation we’ve recorded statistically significant rSO2 growth at 15.6 % compared to the initial values up to the mark of (57.03 ± 7.01) %. Instead, the rSO2 changes in patients of group II (who were performed СРАР-support at night against the traditional treatment of a stroke), were dynamic and statistically probable: a controlled index during the 3rd day of observation has increased at 12.2 %, during the 5th day — at 26.5 %, during the 7th day — at 33.6 % compared to the initial values up to the level of (67.64 ± 3.02) % compared to the initial values. Conclusions. Standardized medicinal therapy and early rehabilitation of patients with ischemic stroke does not affect the course and severity of concomitant obstructive sleep apnea syndrome and requires a supplement with the methods of non-invasive respiratory support during night sleep. Patients with ischemic stroke against the background of autoCPAP-therapy, were recorded positive dynamics in terms of correction of obstructive sleep apnea syndrome and stable normalization of cerebral oxymetry.

Reference Values of Regional Oxygen Saturation (rSO2) Determined by Near-Infrared Spectroscopy (NIRS) for 18 Selected Regions of Interest (ROIs) in Young and Elderly Healthy Volunteers

Regional oxygen saturation (rSO2) assessed by near-infrared spectroscopy (NIRS) reflects the perfusion and metabolism of the assessed tissue. The study aimed to determine the reference values of rSO2 for selected body areas, considering gender, age and body composition. We studied 70 healthy volunteers divided into two age groups (18–30 and &gt;60 years). The rSO2 was measured using NIRS in eighteen selected regions of interest (ROIs). Body composition analysis was carried out using dual-energy X-ray absorptiometry (DXA). Significant differences in rSO2 values were found between almost all analyzed ROIs (p &lt; 0.05) with a simultaneous lack of asymmetry between contralateral side of the body. The average rSO2 values from the ROIs analyzed ranged from 40.34 ± 17.65% (Achilles tendon) to 69.94 ± 6.93% (tibialis anterior muscle). Age and the values of adiposity indices and the fat mass content are factors that may significantly reduce the rSO2 value. In most ROIs, higher rSO2 values were recorded for the younger group (p &lt; 0.0001). The rSO2 values at rest are area-specific in young and elderly healthy subjects. The changes in rSO2, both in clinical assessment and research, should be interpreted taking into account the body area being assessed and individual factors such as age and body fat content.

Oxygen Saturation Increase in Ischemic Wound Tissues after Direct and Indirect Revascularization.

The primary approach for treating ischemic wounds is restoring oxygen supply to the ischemic region. While direct angiosomal revascularization is often associated with better post-operative wound healing and limb salvage, its superiority over non-angiosomal revascularization remains controversial. This study aimed to compare intraoperative tissue oxygen saturation changes in ischemic zones following either direct or indirect revascularization in below-the-knee arteries. This prospective observational study included patients undergoing direct and indirect below-the-knee endovascular revascularizations. Assignment to the groups was not randomized. Near-infrared spectroscopy was used to monitor rSO2 changes near the ischemic wounds intraoperatively. The changes were compared between the groups. 15 patients (50%) underwent direct angiosomal revascularization, while an equal number of patients underwent indirect revascularization. Overall, a statistically significant increase in regional oxygen saturation was observed after revascularization (p = 0.001). No statistically significant difference was found between the direct and indirect revascularization groups (p = 0.619). This study revealed a minor difference in the oxygen saturation increase between the angiosomal and non-angiosomal revascularization groups. Such a finding indicates that the clinical significance of angiosomal revascularization is negligible and might be concealed by confounding factors, such as the vessel diameter and outflow impact on the restenosis rate.

Relationship Between Regional Cerebral Oxygen Saturation and Percutaneous Oxygen Saturation at Initial Mobilisation in Patients with Acute Heart Failure.

In patients with acute heart failure, early mobilisation is performed according to physical condition, biometric information, and haemodynamic stability. Regional cerebral oxygen saturation (rSO2) is useful in monitoring patients during assisted circulation and cardiac arrest, but the measurement of rSO2 during early mobilisation is not standardised, and its relationship with percutaneous oxygen saturation (SpO2) has not been investigated. This study aimed to investigate the relationship between rSO2 and SpO2 during initial mobilisation in patients with acute heart failure. Patients with acute heart failure who presented to our emergency centre and were referred for physical therapy were included in this study. Data from 21 of the 24 patients who decided to start mobilisation based on the criteria of the Japanese Society of Intensive Care Medicine were analysed. The resting rSO2 was 58.6%, and it significantly changed (p<0.001), with a decrease in the first half of sitting on the edge of the bed (SEB) and an increase from the second half to the end of the SEB. The resting SpO2 was 96.0%, with a trend towards an increase in the latter half of the SEB (p=0.05608). Changes in rSO2 during initial mobilisation in patients with acute heart failure differed from those in SpO2.

Effects of Head Elevation on Cerebral Oxygenation in Acute Cerebral Infarction.

This study clarifies the effects of head elevation on cerebral oxygenation in patients with acute cerebral infarction. We included 76 patients with anterior circulation cerebral infarction admitted to the stroke care unit within 7days of symptom onset. Using near-infrared spectroscopy (NIRS), we measured regional saturation oxygen (rSO2), oxygenated haemoglobin (O2Hb), deoxygenated haemoglobin (HHb), and total haemoglobin (THb) in both the affected hemisphere (AH) and unaffected hemisphere (UH) after raising the head to 0°, 30°, and 60° for 1minute each. The mean arterial pressure (MAP) was measured non-invasively at each position. Our result demonstrated a significant decrease in O2Hb as the head elevation angle (HEA) increased, with no observable interaction between the AH and UH. A significant decrease in rSO2 interaction was observed. In contrast, the HHb and THb levels changed significantly as the HEA increased, although no interactions were identified. No significant correlations existed between the observed changes in O2Hb, HHb, THb, or rSO2 and changes in MAP at each HEA.

Effect of Red Blood Cell Transfusion on Regional Tissue Oxygenation in Pediatric Cardiac Surgery Patients.

Red blood cell (RBC) transfusions are used frequently in pediatric patients admitted to the intensive care unit (ICU) after cardiac surgery. To improve data-driven transfusion decision-making in the ICU, we conducted a retrospective analysis to assess the effect of RBC transfusion on cerebral and somatic regional oxygenation (rSO2). We evaluated post- versus pre-RBC transfusion cerebral rSO2 and somatic rSO2 in all consecutive pediatric patients (age >28 days to <18 years) who underwent biventricular cardiac surgery at a single center between July 2016 and April 2020. The final data set included 263 RBC postoperative transfusion events in 75 patients who underwent 83 surgeries. The median pretransfusion hemoglobin was 10.6 g/dL (25th-75th percentile, 9.3-11.6). The median pretransfusion cerebral and somatic rSO2 were 63% (54-71) and 69% (55-80), which increased by a median of 3 percentage points (-2 to 6) and 2 percentage points (-3 to 6), respectively, after transfusion. After adjusting for pretransfusion hemoglobin, change in hemoglobin posttransfusion versus pretransfusion, and potential confounders (age, sex, and STAT surgical mortality risk score), the posttransfusion versus pretransfusion change in cerebral or somatic rSO2 was not statistically significant. Pretransfusion cerebral rSO2 (crSO2) was ≤50%, a previously described threshold for increased risk for unfavorable neurological outcome, for 22 of 138 (16%) transfusion events with complete pre- and post-crSO2 data. Sixteen of these 22 (73%) transfusions resulted in a posttransfusion crSO2 >50%. When restricting analysis to the first (index) transfusion after arrival to the ICU from the operating room (administered at a median of 1.15 postoperative days [25th-75th percentile, 0.84-1.93]), between-patient pretransfusion hemoglobin was not associated with pretransfusion crSO2 but within-patient posttransfusion versus pretransfusion hemoglobin difference was significantly associated with posttransfusion versus pretransfusion crSO2 difference (mean posttransfusion versus pretransfusion crSO2 difference, 2.54; 95% confidence interval, 0.50-4.48). In this study, neither cerebral nor somatic rSO2 increased significantly post- versus pre-RBC transfusion in pediatric cardiac surgery patients admitted to the ICU after biventricular repairs. However, almost three-quarters of transfusions administered when pretransfusion crSO2 was below the critical threshold of 50% resulted in a posttransfusion crSO2 >50%. In addition, the significant within-patient change in crSO2 in relation to the change in posttransfusion versus pretransfusion hemoglobin in the immediate postoperative period suggests that a personalized approach to transfusion following within-patient trends of crSO2 rather than absolute between-patient values may be an important focus for future research.

Temporal Statistical Relationship between Regional Cerebral Oxygen Saturation (rSO2) and Brain Tissue Oxygen Tension (PbtO2) in Moderate-to-Severe Traumatic Brain Injury: A Canadian High Resolution-TBI (CAHR-TBI) Cohort Study.

Brain tissue oxygen tension (PbtO2) has emerged as a cerebral monitoring modality following traumatic brain injury (TBI). Near-infrared spectroscopy (NIRS)-based regional cerebral oxygen saturation (rSO2) can non-invasively examine cerebral oxygen content and has the potential for high spatial resolution. Past studies examining the relationship between PbtO2 and NIRS-based parameters have had conflicting results with varying degrees of correlation. Understanding this relationship will help guide multimodal monitoring practices and impact patient care. The aim of this study is to examine the relationship between PbtO2 and rSO2 in a cohort of TBI patients by leveraging contemporary statistical methods. A multi-institutional retrospective cohort study of prospectively collected data was performed. Moderate-to-severe adult TBI patients were included with concurrent rSO2 and PbtO2 monitoring during their stay in the intensive care unit (ICU). The high-resolution data were analyzed utilizing time series techniques to examine signal stationarity as well as the cross-correlation relationship between the change in PbtO2 and the change in rSO2 signals. Finally, modeling of the change in PbtO2 by the change in rSO2 was attempted utilizing linear methods that account for the autocorrelative nature of the data signals. A total of 20 subjects were included in the study. Cross-correlative analysis found that changes in PbtO2 were most significantly correlated with changes in rSO2 one minute earlier. Through mixed-effects and time series modeling of parameters, changes in rSO2 were found to often have a statistically significant linear relationship with changes in PbtO2 that occurred a minute later. However, changes in rSO2 were inadequate to predict changes in PbtO2. In this study, changes in PbtO2 were found to correlate most with changes in rSO2 approximately one minute earlier. While changes in rSO2 were found to contain information about future changes in PbtO2, they were not found to adequately model them. This strengthens the body of literature indicating that NIRS-based rSO2 is not an adequate substitute for PbtO2 in the management of TBI.

Effects of permissive hypercapnia on intraoperative cerebral oxygenation and early postoperative cognitive function in older patients with non-acute fragile brain function undergoing laparoscopic colorectal surgery: protocol study

BackgroundPerioperative brain protection in older patients has been the focus of research recently; meanwhile, exploring the relationship between regional cerebral oxygen saturation (rSO2) and brain function in the perioperative period has been an emerging and challenging area—the difficulties related to the real-time monitoring of rSO2 and the choice of feasible interventions. As an advanced instrument for intraoperative rSO2 monitoring, the clinical application of near-infrared spectrum (NIRS) cerebral oxygen monitoring has gradually increased in popularity and is being recognized for its beneficial clinical outcomes in patients undergoing cardiac and noncardiac surgery. In addition, although sufficient evidence to support this hypothesis is still lacking, the effect of permissive hypercapnia (PHC) on rSO2 has expanded from basic research to clinical exploration. Therefore, monitoring intraoperative rSO2 in older patients with NIRS technology and exploring possible interventions that may change rSO2 and even improve postoperative cognitive performance is significant and clinically valuable.MethodsThis study is a single-center randomized controlled trial (RCT). 76 older patients are enrolled as subjects. Patients who meet the screening criteria will be randomly assigned 1:1 to the control and intervention groups. PHC-based mechanical ventilation will be regarded as an intervention. The primary outcome is the absolute change in the percent change in rSO2 from baseline to the completion of surgery in the intervention and control groups. Secondary outcomes mainly include observations of intraoperative cerebral oxygenation and metabolism, markers of brain injury, and assessments of patients' cognitive function using scale through postoperative follow-up.DiscussionThe findings of this RCT will reveal the effect of PHC on intraoperative rSO2 in older patients with nonacute fragile brain function (NFBF) and the approximate trends over time, and differences in postoperative cognitive function outcomes. We anticipate that the trial results will inform clinical policy decision-makers in clinical practice, enhance the management of intraoperative cerebral oxygen monitoring in older patients with comorbid NFBF, and provide guidance for clinical brain protection and improved postoperative cognitive function outcomes.Trial registrationChiCTR, ChiCTR2200062093, Registered 9/15/2022.

Statistical properties of cerebral near infrared and intracranial pressure-based cerebrovascular reactivity metrics in moderate and severe neural injury: a machine learning and time-series analysis

BackgroundCerebrovascular reactivity has been identified as a key contributor to secondary injury following traumatic brain injury (TBI). Prevalent intracranial pressure (ICP) based indices of cerebrovascular reactivity are limited by their invasive nature and poor spatial resolution. Fortunately, interest has been building around near infrared spectroscopy (NIRS) based measures of cerebrovascular reactivity that utilize regional cerebral oxygen saturation (rSO2) as a surrogate for pulsatile cerebral blood volume (CBV). In this study, the relationship between ICP- and rSO2-based indices of cerebrovascular reactivity, in a cohort of critically ill TBI patients, is explored using classical machine learning clustering techniques and multivariate time-series analysis.MethodsHigh-resolution physiologic data were collected in a cohort of adult moderate to severe TBI patients at a single quaternary care site. From this data both ICP- and rSO2-based indices of cerebrovascular reactivity were derived. Utilizing agglomerative hierarchical clustering and principal component analysis, the relationship between these indices in higher dimensional physiologic space was examined. Additionally, using vector autoregressive modeling, the response of change in ICP and rSO2 (ΔICP and ΔrSO2, respectively) to an impulse in change in arterial blood pressure (ΔABP) was also examined for similarities.ResultsA total of 83 patients with 428,775 min of unique and complete physiologic data were obtained. Through agglomerative hierarchical clustering and principal component analysis, there was higher order clustering between rSO2- and ICP-based indices, separate from other physiologic parameters. Additionally, modeled responses of ΔICP and ΔrSO2 to impulses in ΔABP were similar, indicating that ΔrSO2 may be a valid surrogate for pulsatile CBV.ConclusionsrSO2- and ICP-based indices of cerebrovascular reactivity relate to one another in higher dimensional physiologic space. ΔICP and ΔrSO2 behave similar in modeled responses to impulses in ΔABP. This work strengthens the body of evidence supporting the similarities between ICP-based and rSO2-based indices of cerebrovascular reactivity and opens the door to cerebrovascular reactivity monitoring in settings where invasive ICP monitoring is not feasible.

Association between regional oxygen saturation and central venous saturation in pediatric patients undergoing cardiac surgery: A prospective observational study.

We evaluated the correlation between regional oxygen saturation (rSO2 ) in the frontal and right renal dorsum (cerebral rSO2 and somatic rSO2 ) measured by near-infrared spectroscopy (INVOS™ 5100C, Medtronic) and central venous oxygen saturation (ScvO2 ) measured with a fiber-optic oximetry catheter (PediaSat™, Edwards Lifesciences) during surgery in order to determine whether noninvasive rSO2 could be used as an alternative to ScvO2 in pediatric cardiac surgery patients. We evaluated the correlation between regional tissue oxygen saturation (cerebral rSO2 and somatic rSO2 ) measured by near-infrared spectroscopy and other patient measures with central venous oxygen saturation (ScvO2 ) measured with a fiber-optic oximetry catheter to track global oxygen supply demand as a potential alternative or supplement to ScvO2 . This single-center prospective observational study enrolled 33 children (weight < 10 kg) who underwent cardiac surgery for congenital heart disease between February 2018 and November 2021. ScvO2 , cerebral rSO2 , and somatic rSO2 were recorded simultaneously after anesthesia induction and central venous catheter placement. Pearson's correlation coefficient and Bland-Altman analysis were used to determine the relationship between ScvO2 and rSO2 . We conducted correlation, Bland Altman, and multiple regression analyses to identify associations between rSO2 , patient measures, and ScvO2 values. The patients' median age was 11.0 (quartile 2.0-16.0) months. Their weight was 7.2 (quartile 4.5-9.2) kg. Cerebral rSO2 was significantly positively correlated with ScvO2 (r2 = 0.29, p = .002 in all patients; r2 = 0.61, p = .013 in the patients without mixing at the atrial level), whereas somatic rSO2 was not. The Bland-Altman analysis demonstrated biases [95% confidence interval; 95% CI] (lower and upper limits of agreement [95% CI]) of 0.27% [-4.26 to 4.80] (-24.79 [-32.61 to -16.96] to 25.33 [17.50 to 33.16]) between cerebral rSO2 and ScvO2 and 0.91% [-5.48 to 7.30] (-34.43 [-45.47 to -23.39] to 36.25 [25.21 to 47.29]) between somatic rSO2 and ScvO2 . Preoperative brain natriuretic peptide (BNP) and SpO2 were independent variables associated with ScvO2 and cerebral and somatic rSO2 . Cerebral rSO2 , SpO2 , and BNP were significantly correlated with ScvO2 , although the cerebral rSO2 correlation was greater for lesions without atrial mixing. rSO2 , BNP, and SpO2 might be used to track changes in ScvO2 but cerebral rSO2 is not sufficiently precise to replace it.

Effects of targeted mild hypercapnia versus normocapnia on cerebral oxygen saturation in patients undergoing laparoscopic hepatectomy under low central venous pressure: a prospective, randomized controlled study

BackgroundLaparoscopic hepatectomy under low central venous pressure (LCVP) is associated with intraoperative organ hypoperfusion, including cerebral hypoperfusion. We hypothesized that a ventilation strategy designed to achieve targeted mild hypercapnia (TMH) (end-tidal carbon dioxide partial pressure [PetCO2] of 45 ± 5 mmHg) rather than targeted normocapnia (TN) (PetCO2 of 30 ± 5 mmHg) would increase regional cerebral oxygen saturation (rSO2) during laparoscopic hepatectomy under LCVP.MethodsEighty patients undergoing laparoscopic hepatectomy under LCVP were randomly divided into the TMH group (n = 40) and the TN group (n = 40). Mechanical ventilation was adjusted to maintain the PetCO2 within the relevant range. Cerebral oxygenation was monitored continuously using the FORE-SIGHT system before anesthetic induction until the patient left the operating room. Patient and surgical characteristics, rSO2, intraoperative hemodynamic parameters (CVP, mean artery blood pressure [MAP], and heart rate), PetCO2, intraoperative blood gas analysis results, and postoperative complications were recorded.ResultsNo significant differences were observed in CVP, MAP, and heart rate between the two groups during surgery. The rSO2 was significantly lower in the TN group on both the left and right sides during the intraoperative period (P < 0.05), while the TMH group had a stable rSO2. In the TN group, the mean rSO2 decreased most during liver parenchymal transection when compared with the baseline value (P < 0.05). The mean (standard deviation) percentage change in rSO2 from baseline to parenchymal transection was − 7.5% (4.8%) on the left and − 7.1% (4.6%) on the right. The two groups had a similar incidence of postoperative complications (P > 0.05).ConclusionOur findings demonstrate that rSO2 is better maintained during laparoscopic hepatectomy under LCVP when patients are ventilated to a PetCO2 of 45 ± 5 mmHg (TMH) than a PetCO2 of 30 ± 5 mmHg (TN).Trial registrationChiCTR2100051130(14/9/2021).

Differences between Hepatic and Cerebral Regional Tissue Oxygen Saturation at the Onset of Intradialytic Hypotension.

Intradialytic hypotension (IDH) is a critical pathological condition associated with all-cause mortality in patients undergoing hemodialysis (HD). However, few studies have investigated IDH-related changes in hepatic and cerebral regional tissue oxygen saturation (rSO2). This study investigated IDH-induced changes in hepatic and cerebral rSO2. Hepatic and cerebral rSO2 during HD were measured using an INVOS 5100C oxygen saturation monitor, and their percentage (%) changes during the development of IDH were analyzed. Ninety-one patients undergoing HD were investigated, including twenty with IDH. In patients with IDH, % changes in hepatic and cerebral rSO2 decreased at the onset of IDH. Additionally, the % change in hepatic rSO2 was significantly larger than that in cerebral rSO2 (p < 0.001). In patients without IDH, no significant differences were found between the % changes in hepatic and cerebral rSO2 at the time of the lowest systolic blood pressure during HD. Multivariable linear regression analysis showed that the difference between the % changes in cerebral and hepatic rSO2 was significantly associated with the development of IDH (p < 0.001) and the ultrafiltration rate (p = 0.010). Hepatic and cerebral rSO2 significantly decreased during the development of IDH, and hepatic rSO2 was more significantly decreased than cerebral rSO2 at the onset of IDH.

Utility of cerebral oximetry in balloon mitral valvotomy and its correlation with post-procedure neurological complications: A pragmatic prospective observational study.

Neurological complications (NCs) are significantly associated with reduced regional cerebral saturation (rSO2) in patients undergoing cardiac surgeries, as assessed with cerebral oximetry (COx). However, limited evidence is available in patients undergoing balloon mitral valvotomy (BMV). Thus, we evaluated the utility of COx in patients undergoing BMV, the incidence of BMV-related NCs and the association of >20% reduction in rSO2 with NCs. This pragmatic, prospective, observational study was performed after ethical approval, over November 2018 to August 2020, in the cardiology catherization laboratory of a tertiary care hospital. The study involved 100 adult patients undergoing BMV for symptomatic mitral stenosis. The patients were evaluated at initial presentation, pre-BMV, post-BMV and 3 months after the BMV. The incidence of NCs was 7%, including transient ischaemic attack (n = 3), slurred speech (n = 2) and hemiparesis (n = 2). A significantly greater proportion of patients with NCs had a > 20% decrease in the rSO2 (P value = 0.020). At >20% cut-off, the COx had a sensitivity and specificity of 57.1% and 80%, respectively, in the prediction of NCs. Female sex (P value = 0.039), history of cerebrovascular episodes (P value < 0.001) and number of balloon attempts (P value < 0.001) were significantly associated with NCs. Patients with and without NCs had a significantly greater post-BMV mean % change in rSO2 than pre-BMV (both right and left sides), but the magnitude of mean % change was greater in those with NCs. COx alone has low sensitivity and specificity in the prediction of NCs and cannot reliably predict the development of post-BMV NCs.

Factors affecting intradialytic hepatic oxygenation: Associations between ultrafiltration rate and changes in systemic blood pressure

Hepato-splanchnic circulation influences the oxygenation of abdominal organs and is important in preventing a reduction in intradialytic blood volume. However, the association between changes in intradialytic hepato-splanchnic circulation and clinical factors remain unknown. We enrolled 91 hemodialysis (HD) patients (20 with intradialytic hypotension (IDH) and 71 without IDH). During HD, hepatic regional oxygen saturation (rSO2), a marker of hepatic oxygenation reflecting hepato-splanchnic circulation and oxygenation, was monitored. Changes in hepatic rSO2 at the lowest systolic blood pressure (BP) during HD were analyzed to identify associations with clinical factors. Hepatic rSO2 levels were 55.8 ± 15.3% before HD and 53.8 ± 14.9% at the lowest systolic BP; therefore, % changes in hepatic rSO2 were -2.7 ± 11.3%. These values were significantly lower in patients with IDH than in those without IDH (-13.8 ± 9.3% vs 0.4 ± 9.8%, p < 0.001). Multivariable regression analysis showed that % changes in hepatic rSO2 were independently associated with % changes in systolic BP (standardized coefficient: 0.416) and ultrafiltration rate (-0.206). Furthermore, % changes in mean BP (0.304) were identified as affecting % changes in hepatic rSO2 instead of those in systolic BP. Changes in intradialytic hepatic oxygenation is associated with ultrafiltration rate and changes in systemic BP. Further studies are required to clarify the directionality of the association between changes in hepatic oxygenation and changes in systemic BP during HD.