Cerebral Oxygenation In Patients Research Articles

The Impact of Inotropes and Vasopressors on Cerebral Oxygenation in Patients with Traumatic Brain Injury and Subarachnoid Hemorrhage: A Narrative Review.

Traumatic brain injury (TBI) and subarachnoid hemorrhage (SAH) are critical neurological conditions that necessitate specialized care in the Intensive Care Unit (ICU). Managing cerebral perfusion pressure (CPP) and mean arterial pressure (MAP) is of primary importance in these patients. To maintain targeted MAP and CPP, vasopressors and/or inotropes are commonly used. However, their effects on cerebral oxygenation are not fully understood. The aim of this review is to provide an up-to date review regarding the current uses and pathophysiological issues related to the use of vasopressors and inotropes in TBI and SAH patients. According to our findings, despite achieving similar hemodynamic parameters and CPP, the effects of various vasopressors and inotropes on cerebral oxygenation, local CBF and metabolism are heterogeneous. Therefore, a more accurate understanding of the cerebral activity of these medications is crucial for optimizing patient management in the ICU setting.

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.

The Impact of Various Anesthetic Techniques on Cerebral Oxygenation during Spinal Surgery Performed in a Prone Position with Controlled Hypotension

Background: While prone positioning during anesthesia is necessary for certain surgical procedures, it also increases the risk of postoperative neurological complications. This risk is exacerbated by controlled hypotension used to minimize blood loss during spinal surgeries. Monitoring regional cerebral oxygen saturation (rScO2 ) is essential for maintaining cerebral oxygenation and preventing adverse outcomes like cognitive dysfunction and organ failure. This study aimed to evaluate the effect of different anesthetic techniques on cerebral oxygenation in patients undergoing spinal surgery in the prone position with controlled hypotension. Methods: Fifty-four patients scheduled for spinal surgery in a prone position with controlled hypotension were randomly assigned into two equal groups, to receive sevoflurane or propofol anesthesia. Data were collected at various intervals: before and after anesthesia induction, post-induction in the prone position, during surgery, and before awakening in the supine position. Parameters recorded included rScO2 , peripheral oxygen saturation (SpO2), heart rate (HR), patient state index (PSI), end-tidal carbon dioxide tension (ETCO2 ), and mean arterial pressure (MAP). Results: rScO2 levels decreased in both patient groups once positioned in the prone position. However, the rScO2 values were significantly lower in the propofol group compared to the other group (p = 0.025, 0.032 respectively). Conclusion: The study suggests that propofol as the anesthetic agent may have exacerbated the decline in cerebral oxygenation associated with the transition to prone positioning. Sevoflurane might thus be preferable for patients at risk of compromised cerebral oxygenation.

The utility of NIRS in follow-up of patients with acute ischaemic stroke treated with IV thrombolysis and mechanical thrombectomy in the emergency department.

Revascularization treatments (IV thrombolysis, mechanical thrombectomy) related to ischemic stroke have developed in recent years. With devices such as NIRS, non-invasive monitoring of treatment efficacy is provided. In this study, we aimed to use near-infrared spectroscopy (NIRS) as an objective monitoring method to see the effect of intravenous (IV) thrombolysis or mechanical thrombectomy treatments applied for cerebral oxygenation in patients with acute ischemic stroke.This study was carried out as a prospective study involving patients admitted to the emergency department in the years 2021-2022. NIRS measured regional oxygen saturation (rSO2) of both hemispheres of the brain before IV thrombolysis treatment, during the treatment at 0. min, 15. min, 30. min, 45. min, 60. min, after the treatment, and before and after the mechanical thrombectomy procedure. The significance level of the change in rSO2 values measured by NIRS was examined.80 patients were included in the study. IV thrombolysis was applied to 58 patients, mechanical thrombectomy was applied to 5 of them, and both treatments were applied to 17 of them. In patients receiving IV thrombolysis, a significant difference was found in the affected hemisphere between the NIRS values measured at 0.min-15.min, 0.min-30.min, 0.min-45.min, 0.min-60.min, 0.min-post-treatment, 15.min-60.min (p < 0.001). In the patients included in the study, there was a strong and significant negative correlation between the deltaNIHSS value and the deltaNIRS values in the affected hemisphere (r=- 0.307, p = 0.013). There was a significant increase in the NIRS measurement values during and after the IV thrombolysis treatment in the affected hemisphere in the group with clinical improvement (p < 0.001).It is thought that IV thrombolysis or mechanical thrombectomy treatment applied to patients admitted to the emergency department with acute ischemic stroke can be followed objectively by NIRS.

Airway management with novel intubating laryngeal tubes has no influence on cerebral oxygenation in cardiac surgery patients: A prospective observational study

BackgroundA laryngeal tube is often used as an alternative to intubation with direct laryngoscopy during cardiopulmonary resuscitation. However, in a study with piglets undergoing simulated cardiac arrest, reduced carotid artery blood flow was associated with the insertion of different supraglottic airway devices, such as a laryngeal tube. Limited by its construction, secondary tracheal intubation through a laryngeal tube was difficult or impossible in contrast to a second generation laryngeal mask. The new disposable intubating laryngeal tube with suction (iLTS-D®) seems to facilitate tracheal intubation. We hypothesized that iLTS-D, when inflated to the recommended air volume, does not reduce cerebral oxygenation in patients with cardiovascular diseases undergoing elective cardiac surgery.MethodsThis single-center prospective, controlled observational study was approved by the local ethics committee (Ethical Committee No. 2018-13716). Forty adult patients undergoing elective cardiac surgery requiring tracheal intubation were included in this study. The exclusion criteria were age &amp;lt;18 years and a high risk of aspiration, inability to consent, height &amp;lt;155 cm, or pregnancy. Prior to insufflation and deflation of the cuffs, we performed cerebral oximetry via near-infrared spectroscopy. The primary outcome was a significant reduction in NIRS in the context of the preinduction baseline value after inflation of the cuffs with the recommended air volume, defined as a ≥25% decrease from baseline or an absolute value ≤ 50%. The secondary endpoints were differences in time points, insertion success rates, and complications.ResultsThere was no significant reduction in cerebral oximetry after inflation with the recommended cuff volume and an initially measured cuff pressure of &amp;gt;120 cmH2O. Overall, tracheal intubation was achieved in a median of 20 s [interquartile range 15-23 s] and enabled sufficient ventilation and tracheal intubation through the iLTS-D in all patients. Traces of blood on the cuffs (after removing the iLTS-D) and a sore throat (evaluated 2 h after removing the tracheal tube) were observed in one patient.ConclusionOur results showed no association between the insertion of the iLTS-D and reduced cerebral oxygenation in patients undergoing elective cardiac surgery.Trial registrationClinicalTrials.gov, NCT03942809.

Regional Cerebral Oxygenation in Patients with Severe COVID-19

The aim of the study was to assess regional cerebral oxygenation (rScO₂) in patients with acute respiratory distress syndrome (ARDS) associated with COVID-19.Material and methods. The cross-sectional study was conducted. Twenty-eight patients with severe COVID-19 who were admitted in the intensive care unit were enrolled. Regional cerebral oxygenation was assessed using near-infrared spectroscopy, laboratory markers of cerebral damage, clinical and laboratory characteristics.Results. Median age of patients was 65 years, of whom 50% were men. Three (11%) patients had severeARDS, 8 (29%) patients had moderate ARDS, and 17 (60%) patients had mild ARDS. Mechanical ventilation was performed in 20 (71%) patients, vasopressors were used in 14 (50%) patients. The median levels of cerebral saturation were normal and did not differ between the left (rScO₂l) and right (rScO₂r) hemispheres (68 (58–75) and 69 (59–76), respectively). The level of S-100 protein was increased (0.133 (0.061–0.318) µg/l) in contrast to the normal level of neuron-specific enolase (12.5 (8.0–16.5) µg/l). A correlation was found only between rScO₂ and hemoglobin level (rho=0.437, P=0.02) and between rScO₂ and lymphocyte count (rho=–0.449, P=0.016). An increase in S-100 negatively correlated with a decrease in Glasgow Coma Scale score (rho=–0.478, P=0.028).Conclusion. Near-infrared spectroscopy did not reveal a decrease in rScO₂ among patients with ARDS associated with COVID-19. The S-100 protein is a useful marker for the assessment of impaired consciousness. Further study of the causes of cerebral dysfunction in patients with severe COVID-19 and methods for its early identification is warranted.

Cerebral oxygenation during cardiopulmonary exercise testing of patients with cardiovascular and respiratory diseases: a systematic review

Abstract Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): National Council for Scientific and Technological Development - CNPq (310612/2019-5) and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES (001) Background Cardiopulmonary exercise testing (CPET) has been widely used in clinical practice to determine aerobic capacity and assess the integrity of cardiovascular, respiratory, muscular and neurohumoral adjustments in health and disease. However, little is known about the acute cerebral oxygenation responses during CPET in cardiorespiratory patients, to increase safety for the physical intervention protocols development. Purpose To conduct a systematic review to evaluate the cerebral oxygenation acute responses during CPET in patients with cardiovascular, metabolic or respiratory diseases. Methods This systematic review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement. Five electronic databases PubMed, Scopus, Web of Science, Embase and Cinahal were searched from the inception to November 10th, 2021. The eligibility criteria were determined considering the PICOS format: patients with heart, metabolic or respiratory disease (P); who carried out incremental CPET (I); compared with healthy subjects (C); our results of interest were cerebral oxygenation response through near-infrared spectroscopy (NIRS) (O); in cross-sectional studies (S). The articles were independently selected by two researchers and the disagreements were solved by a third researcher. The ROBINS I scale assessed the risk of bias of the eligible studies. Results The initial search identified 3557 articles and 4 additional articles were identified through other sources (references of eligible articles). After screening and deleting the duplicated articles, 7 studies were included. The studies were classified as moderate risk of bias and the most questioned domains were due to outcome measurement and due to selection of reported result. This systematic review analyzed 428 individuals, 305 men and 123 women aged between 43 to 70 years. Of these, 247 had diagnosis of cardiovascular disease (101 with heart failure NYHA II and III; 77 idiopathic dilated cardiomyopathy; 33 valvular disease; 25 coronary artery disease; 22 pulmonary arterial hypertension); 15 with severe obstructive sleep apnea and 166 apparently healthy. No article was found with metabolic disease. The results showed impairment of cerebral oxygenation, evaluated by NIRS, in patients with cardiovascular diseases during the CPET compared with healthy individuals. On the other hand, severe obstructive sleep apnea was not related with a poorer cerebral oxygenation during CPET. Conclusion The acute CPET response negatively impacts the cerebral oxygenation in patients with cardiovascular diseases. Taking into account the considered risk of bias of the included studies, more attention is necessary to ensure greater safety for testing maximal exercise in cardiac patients.

Effect of desflurane on changes in regional cerebral oxygenation in patients undergoing one-lung ventilation is equivalent to the effect of propofol

ObjectivesDesaturation is an important clinical problem during one-lung ventilation (OLV) since it may induce cerebral hypoxia. Measurement of cerebral oxygenation has been shown to provide accurate information about episodes of cerebral hypoxemia. The purpose of this study was to compare the effect of desflurane on changes in cerebral oxygenation during OLV with the effect of propofol. MethodsA randomized, single-blinded, prospective study was conducted. Fifty adult patients who were scheduled to undergo thoracic surgery were randomly assigned to anesthetic management using desflurane with remifentanil (Group D: n = 25) or using propofol and remifentanil (Group P: n = 25). ResultsThe characteristics of the patients were very similar. Intergroup analysis of changes in cerebral oxygenation showed no significant difference on the operative side (two-way ANOVA, F (7, 368) = 0.425, p = 0.887) or the non-operative side (two-way ANOVA, F (7, 367) = 1.342, p = 0.229). Intragroup analysis of changes in cerebral oxygenation using one-way ANOVA showed no significant difference on the operative side (Group P; p = 0.585, Group D; p = 0.928) or the non-operative side in both groups (Group P; p = 0.657, Group D; p = 0.602). ConclusionsThe effects of desflurane and propofol on changes in cerebral oxygenation in patients undergoing OLV were equivalent. Our results indicated that desflurane might be an appropriate anesthetic during OLV for maintaining cerebral oxygenation with an effective equivalent to that of propofol.

Clinical factors affecting cerebral oxygenation in patients undergoing peritoneal dialysis.

Although cerebral regional oxygen saturation (rSO2) is significantly lower in hemodialysis (HD) patients than that in healthy controls, investigations on cerebral oxygenation in peritoneal dialysis (PD) patients are limited. We aimed to confirm the cerebral oxygenation status and identify the factors affecting cerebral rSO2 in PD patients. Thirty-six PD patients (21 men and 15 women; mean age, 62.8 ± 12.7 years) were recruited. In addition, 27 healthy volunteers (17 men and 10 women; mean age, 43.5 ± 18.8 years) were recruited as a control group. Cerebral rSO2 was monitored at the forehead using an INVOS 5100c oxygen saturation monitor. Cerebral rSO2 was significantly lower in PD patients than that in healthy controls (57.0 ± 7.3% vs 68.9 ± 8.6%, p < 0.001); moreover, cerebral rSO2 was significantly correlated with natural logarithm (Ln)-PD duration (r = -0.389, p = 0.019) and serum albumin concentration (r = 0.370, p = 0.026) in a simple linear regression analysis. Multivariable linear regression analysis was performed using variables that showed a significant correlation and p < 0.20 (serum creatinine, serum sodium, Ln-C-reactive protein, and dosage of erythropoiesis-stimulating agent) with the cerebral rSO2. Cerebral rSO2 was independently associated with Ln-PD duration (standardized coefficient: -0.339) and serum albumin concentration (standardized coefficient: 0.316). Cerebral rSO2 was significantly affected by the PD duration and serum albumin concentration. Further prospective studies are needed to clarify whether preventing a decrease in serum albumin concentration leads to the maintenance of cerebral oxygenation in patients undergoing PD.

Combined mental task and metaboreflex impair cerebral oxygenation in patients with type 2 diabetes mellitus.

Cardiovascular regulation is altered by type 2 diabetes mellitus (DM2), producing an abnormal response to muscle metaboreflex. During physical exercise, cerebral blood flow is impaired in patients with DM2, and this phenomenon may reduce cerebral oxygenation (COX). We hypothesized that the simultaneous execution of a mental task (MT) and metaboreflex activation would reduce COX in patients with DM2. Thirteen individuals suffering from DM2 (6 women) and 13 normal age-matched controls (CTL, 6 women) participated in this study. They underwent five different tests, each lasting 12 min: postexercise muscle ischemia (PEMI) to activate the metaboreflex, control exercise recovery (CER), PEMI+MT, CER+MT, and MT alone. COX was evaluated using near-infrared spectroscopy with sensors applied to the forehead. Central hemodynamics was assessed using impedance cardiography. We found that when MT was superimposed on the PEMI-induced metaboreflex, patients with DM2 could not increase COX to the same extent reached by the CTL group (101.13% ± 1.08% vs. 104.23% ± 2.51%, P < 0.05). Moreover, patients with DM2 had higher mean blood pressure and systemic vascular resistance as well as lower stroke volume and cardiac output levels compared with the CTL group, throughout our experiments. It was concluded that patients with DM2 had reduced capacity to enhance COX when undertaking an MT during metaboreflex. Results also confirm that patients with DM2 had dysregulated hemodynamics during metaboreflex, with exaggerated blood pressure response and vasoconstriction. This may have implications for these patients' lack of inclination to exercise.

Effects of Sevoflurane and Propofol Anesthesia on Cerebral Oxygenation in Patients Undergoing Carotid Endarterectomy.

To compare the effects of sevoflurane and propofol anesthesia on perioperative cerebral oxygenation in patients undergoing carotid endarterectomy (CEA) under general anesthesia by using near-infrared spectroscopy (NIRS) monitoring. Institutional approval was obtained, and the perioperative data of 33 patients undergoing CEA were retrospectively evaluated. The study groups were organized according to the anesthesia drugs used for maintenance: sevoflurane (n=17) and propofol (n=16). The regional cerebral oxygen saturation (rScO < sub > 2 < /sub > ) of the ipsilateral and contralateral hemispheres was monitored continuously using a NIRS instrument and analyzed at specific time points starting from induction to the 12th hour postoperation. The data were analyzed using the appropriate tests, and a p value of < 0.05 was considered significant. Compared with those of groups with non-clamped hemispheres, the rScO < sub > 2 < /sub > values of the sevoflurane and propofol groups decreased significantly during clamping (p < 0.05) and increased to above-preoperative values after declamping (p < 0.05). When the sevoflurane and propofol groups were compared, a significant decrease in rScO < sub > 2 < /sub > was noted during extubation in the sevoflurane group (p < 0.05). In the propofol group, female patients had significantly lower rScO < sub > 2 < /sub > values compared with male patients during clamping of the carotid artery (p < 0.05). None of the observed decreases was greater than 20%, which is considered an indication for shunting. Our NIRS monitoring results indicate that sevoflurane or propofol anesthesia does not generally cause significant differences in cerebral oxygenation during and after cross-clamping in patients undergoing CEA. The finding of sex-related differences in cerebral oxygenation in patients receiving propofol and decreased oxygenation during extubation in patients receiving sevoflurane warrants further studies.

The 15° reverse Trendelenburg position can improve visualization without impacting cerebral oxygenation in endoscopic sinus surgery—A prospective, randomized study

In this study we compared intraoperative bleeding and regional cerebral oxygenation in patients with different degrees of the reverse Trendelenburg position (RTP) during endoscopic sinus surgery (ESS). In total, 120 patients with chronic rhinosinusitis treated by ESS were randomly assigned to the following 4 groups: a horizontal position (HP) group, and 5°, 10°, and 15° RTP (5-RTP, 10-RTP, and 15-RTP, respectively) groups. The primary outcome was the Boezaart grading scale (BS). The cerebral oxygen saturation (ScO2 ), total blood loss, numerical rating scale (NRS) scores, and complications were also recorded. The median BS values in the HP, 5-RTP, 10-RTP, and 15-RTP groups were 2.0, 2.0, 2.1, and 1.7, respectively. Multiple pairwise comparisons of the BS showed significant differences between the 15-RTP group and the other 3 groups (HP, 5-RTP, and 10-RTP). Regarding the NRS and bleeding rate, significant differences were found between the HP and 15-RTP groups. No difference was found in ScO2 among the 4 groups, and no cerebral desaturation events occurred in any group. No complications, including vital organ (heart, brain, and kidney) dysfunction problems, were reported in this study during hospitalization. Compared with HP, 5-RTP, and 10-RTP, 15-RTP can improve visual clarity during ESS, and ScO2 is not affected by the degree of RTP. No cerebral deoxygenation or vital organ dysfunction was observed in this study. Therefore, we recommend 15-RTP with moderate deliberate hypotension for ESS.

Cerebral oxygenation in 45-degree trendelenburg position for robot-assisted radical prostatectomy: a single-center, open, controlled pilot study

BackgroundWithin the last decade, robotically-assisted laparoscopic prostatectomy (RALP) has become the standard for treating localized prostate cancer, causing a revival of the 45° Trendelenburg position. In this pilot study we investigated effects of Trendelenburg position on hemodynamics and cerebral oxygenation in patients undergoing RALP.MethodsWe enrolled 58 patients undergoing RALP and 22 patients undergoing robot-assisted partial nephrectomy (RAPN) (control group) in our study. Demographic patient data and intraoperative parameters including cerebral oxygenation and cerebral hemodynamics were recorded for all patients. Cerebral function was also assessed pre- and postoperatively via the Mini Mental Status (MMS) exam. Changes in parameters during surgery were modelled by a mixed effects model; changes in the MMS result were evaluated using the Wilcoxon signed rank test.ResultsPreoperative assessment of patient characteristics, standard blood values and vital parameters revealed no difference between the two groups.ConclusionsApplying a 45° Trendelenburg position causes no difference in postoperative brain function, and does not alter cerebral oxygenation during a surgical procedure lasting up to 5 h. Further studies in larger patient cohorts will have to confirm these findings.Trial registrationGerman Clinical Trial Registry; DRKS00005094; Registered 12th December 2013—Retrospectively registered; https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00005094.

Abstract 276: The Effects of Peep and Blood Pressure on Cerebral Tissue Oxygen Saturation During Hemorrhage in Swine

Introduction: Positive end-expiratory pressure (PEEP) is used to increase oxygen delivery by preventing end-expiratory alveolar collapse. However, the associated increased intrathoracic pressure can lead to an increase in right atrial pressure, and a decrease in venous return and cardiac output. Near infrared spectroscopy (NIRS) can be used as a non-invasive tool to continuously monitor cerebral tissue oxygen saturation. In this pilot study, we examined the effects of PEEP on cerebral oxygen saturation during a controlled hemorrhage. Methods: Four female, domestic swine (~30 kg), were bled to 3 target levels of mean arterial pressure (MAP; 55, 45, and 35 mm Hg). At each MAP target, 3 levels of PEEP were applied using a mechanical ventilator (5, 10, and 15 cm H 2 O) for ~10 minutes each. Following the reinfusion of shed blood and a recovery period, these interventions were repeated. Measurements included invasive aortic pressure and cerebral oxygen saturation using a commercially available tissue oximeter. A total of 61 epochs were entered into the following regression model: cerebral oxygen saturation = MAP + PEEP + animal number. Each epoch contained data from the last ~2 minutes of each MAP target and PEEP level. Results: The regression model yielded a coefficient of 0.30 for MAP ( P &lt; 0.001) and -0.08 for PEEP ( P = 0.09) and overall, explained 94% of the variance in cerebral oxygenation (adjusted R 2 = 0.94, P &lt; 0.001). While MAP was a stronger predictor in the model, higher PEEP levels appear to result in lower levels of cerebral oxygenation (see figure). Conclusions: Cerebral tissue oxygen saturation declines with lower mean arterial pressures and increased levels of PEEP. NIRS to measure cerebral oxygen saturation may be a useful clinical tool to ensure adequate cerebral oxygenation in patients with hypotension related to hemorrhage, particularly in those patients that require greater than physiologic PEEP to maintain central oxygenation.

Cerebral Oxygenation during Exercise in Patients with Cardiopulmonary Diseases: A Prospective Observational Study.

The relationship between exercise and cerebral oxygenation has gained increasing attention. However, few studies have investigated the correlation between exercise and cerebral oxygenation in patients with cardiopulmonary diseases. To investigate the correlation between exercise and cerebral oxygenation in patients with cardiopulmonary diseases. Thirty eligible patients with cardiopulmonary diseases underwent incremental cardiopulmonary exercising test (CPET) and near-infrared spectroscopy with both right and left sensors placed at the mid forehead to detect oxygen saturation of cerebral tissue (STO2). Parameters of cerebral oxygenation and exercise intensity were collected and analyzed. The average age of the patients was 51.17 ± 10.21 years and included 23 males and 7 females. The average maximal STO2 of the left and right brain during CPET were 51.850 ± 1.57% and 51.755 ± 1.90%, respectively. Meanwhile, mean oxygen consumption (VO2) while reaching maximal STO2 was 4.42 ± 1.05 metabolic equivalents (METs) over the left brain and 4.34 ± 1.17 METs over the right brain. The exercise intensity upon reaching maximal STO2 was 84.91 ± 11.70% over the left brain and 83.16 ± 14.64% over the right brain. Peak VO2 was significantly correlated to VO2 upon reaching maximal STO2 over the left and right brain (R = 0.805, p < 0.001 and R = 0.739, p < 0.001, respectively). Age was significantly negatively correlated to VO2 upon maximal STO2 over the left and right brain (R = -0.378, p = 0.039 and R = -0.513, p = 0.004, respectively). Cerebral oxygenation increases with higher exercise intensity, and it reaches a maximal STO2 between respiratory compensation point and peak exercise. The higher the peak VO2, the better the VO2 upon reaching maximal STO2.

Continuous Near-infrared Spectroscopy Monitoring in Adult Traumatic Brain Injury: A Systematic Review

Near-infrared spectroscopy (NIRS) may provide a noninvasive way to monitor cerebral oxygenation in patients with traumatic brain injury, therein allowing for timely intervention aimed at reversing regional brain tissue hypoxia. We conducted a systematic review of NIRS-based oximetry measurements and their association with (A) patient functional outcome (B) other neurophysiological parameters. We searched MEDLINE, EMBASE, SCOPUS, BIOSIS, GlobalHealth and Cochrane Databases from inception to December 2018 and relevant conference proceedings published over the last 5 years. A total of 42 studies meeting our inclusion criteria were found (37 prospective observational, 5 retrospective designs). Seven studies reporting on the association between NIRS-based cerebral oxygenated hemoglobin measurements, mortality, modified Rankin Scale, Glasgow Outcome Scale, or Extended Glasgow Outcome Scale were identified. Forty-two studies exploring associations with neurophysiological parameters were included. Notwithstanding significant gaps in the currently available literature, our analysis suggests a link between NIRS-detected cerebral hypoxia during the acute phase of traumatic brain injury and poor functional outcome. NIRS measurements appear to reflect changes in intracranial pressure, invasively monitored brain tissue oxygen tension and various cerebrovascular reactivity indices although low quality contradicting data exist. More importantly, our review highlights the need for more prospective work before routine integration of NIRS-based techniques into multimodality monitoring regimen.

Effect of Combined Mental Task and Metaboreflex Activation on Hemodynamics and Cerebral Oxygenation in Patients With Metabolic Syndrome.

Objective: The hemodynamic response to muscle metaboreflex has been reported to be significantly altered by metabolic syndrome (MS), with exaggerated systemic vascular resistance (SVR) increments and reduced cardiac output (CO) in comparison to healthy controls (CTLs). Moreover, patients with metabolic disorders, such as type 2 diabetes, have proven to have impaired cerebral blood flow in response to exercise. Thus, we hypothesized that contemporary mental task (MT) and metaboreflex would result in reduced cerebral oxygenation (COX) in these patients.Methods: Thirteen MS patients (five women) and 14 normal age-matched CTLs (six women) were enrolled in this study. All the participants underwent five different tests, each lasting 12 min: post-exercise muscle ischemia (PEMI) to activate the metaboreflex, control exercise recovery (CER), PEMI + MT, CER + MT, and MT alone. Cerebral oxygenation was evaluated using near-infrared spectroscopy with sensors applied to the forehead. Hemodynamics were measured using impedance cardiography.Results: The main results show that MS patients had higher SVR and lower CO levels compared to the CTL group during metaboreflex activation. Stroke volume and ventricular filling and emptying rates were also significantly reduced. Moreover, when MT was added to PEMI, COX was significantly increased in the CTL group with respect to the baseline (103.46 ± 3.14%), whereas this capacity was reduced in MS patients (102.37 ± 2.46%).Conclusion: It was concluded that (1) patients with MS showed hemodynamic dysregulation during the metaboreflex, with exaggerated vasoconstriction and that (2) as compared to CTL, MS patients had reduced capacity to enhance COX when an MT superimposed the metaboreflex.

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.

Effects of dietary intake and nutritional status on cerebral oxygenation in patients with chronic kidney disease not undergoing dialysis: A cross-sectional study.

Dietary management is highly important for the maintenance of renal function in patients with chronic kidney disease (CKD). Cerebral oxygen saturation (rSO2) was reportedly associated with the estimated glomerular filtration rate (eGFR) and cognitive function. However, data concerning the association between cerebral rSO2 and dietary intake of CKD patients is limited. This was a single-center observational study. We recruited 67 CKD patients not undergoing dialysis. Cerebral rSO2 was monitored using the INVOS 5100c oxygen saturation monitor. Energy intake was evaluated by dietitians based on 3-day meal records. Daily protein and salt intakes were calculated from 24-h urine collection. Multivariable regression analysis showed that cerebral rSO2 was independently associated with energy intake (standardized coefficient: 0.370) and serum albumin concentration (standardized coefficient: 0.236) in Model 1 using parameters with p < 0.10 in simple linear regression analysis (body mass index, Hb level, serum albumin concentration, salt and energy intake) and confounding factors (eGFR, serum sodium concentration, protein intake), and the energy/salt index (standardized coefficient: 0.343) and Hb level (standardized coefficient: 0.284) in Model 2 using energy/protein index as indicated by energy intake/protein intake and energy/salt index by energy intake/salt intake in place of salt, protein and energy intake. Cerebral rSO2 is affected by energy intake, energy/salt index, serum albumin concentration and Hb level. Sufficient energy intake and adequate salt restriction is important to prevent deterioration of cerebral oxygenation, which might contribute to the maintenance of cognitive function in addition to the prevention of renal dysfunction in CKD patients.

The relationship between cerebral oxygenation detected by near-infrared spectroscopy and exercise intensity in patients with cardiac diseases

Studies using near-infrared spectroscopy (NIRS) have clearly shown an inverted U-shape relationship between cerebral oxygenation and exercise intensity in healthy adults. However, the pattern of cerebral oxygenation in patients during exercise has not been adequately established. The aim of this study was to investigate the correlation between cerebral oxygenation and exercise intensity in patients with cardiac diseases in order to find the optimal exercise intensity while prescribing cardiac rehabilitation. This observational study included 18 patients with coronary artery disease (CAD) ( n = 9), mitral valve regurgitation (MVR) ( n = 4), congestive heart failure (CHF) ( n = 4) and atrial septal defect(ASD) ( n = 1). They performed incremental cardiopulmonary exercise test (CPET) using a cycle ergometer by the ramp 10 W/min. The concentration of oxyhemoglobin (HbO 2 ), total hemoglobin (HbT) and tissue hemoglobin saturation (STO 2 ) were measured by two bands of non-invasive NIRS positioned on bilateral frontal area during the CPET. The exercise intensity related to highest STO 2 of the two hemispheres were determined. The mean ± standard deviation (SD) age of the study cohort was 58.22 ± 10.12 years and was comprised predominantly of men (77.8%). Five patients reached highest STO 2 during warm-up, 3 after anaerobic threshold, 4 after respiratory compensation point, 6 during recovery stage. The 5 patients with downsloping STO 2 were patients with MR ( n = 3), with ASD ( n = 1), and with CHF ( n = 1). Excluding the 5 patients of downsloping pattern, the mean highest STO 2 of right hemisphere was 49.6622 ± 1.8046 (mM) and left hemisphere was 50.5095 ± 1.7310 (mM). The mean percentage to peak oxygen consumption during highest STO 2 of right hemisphere was 76.27 ± 14.02 (%), left hemisphere was 72.14 ± 17.94 (%). The relationship between cerebral oxygenation and exercise intensity in patients with cardiac diseases such as CAD and CHF revealed a trend as inverted U-shape, with the peak STO 2 located at moderate to high exercise intensity.