Regional Oxygen Saturation Research Articles

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.

Near-Infrared Spectroscopy Monitoring to Detect Changes in Cerebral and Renal Perfusion During Hypovolemic Shock, Volume Resuscitation, and Vasoconstriction.

Rapidly changing hemodynamic conditions, such as uncontrolled hemorrhage and the resulting hypovolemic shock, are a common contributor to active duty military deaths. These conditions can cause cerebral desaturation, and outcomes may improve when regional cerebral oxygen saturation (CrSO2) is monitored using near-infrared spectroscopy (NIRS) and desaturation episodes are recognized and reversed. The purpose of this porcine study was to investigate the ability of NIRS monitoring to detect changes in regional cerebral and regional renal perfusion during hypovolemia, resuscitation by volume infusion, and vasoconstriction. Hemorrhagic shock was induced by removing blood through a central venous catheter until mean arterial pressure (MAP) was <40 mmHg. Each blood removal step was followed by a 10-minute stabilization period, during which cardiac output, blood pressure, central venous pressure, blood oxygen saturation, and CrSO2 and regional renal oxygen saturation (RrSO2) were measured. Shock was reversed using blood infusion and vasoconstriction separately until MAP returned to normal. Statistical comparisons between groups were performed using the paired t-test or the Wilcoxon signed-rank test. Using volume resuscitation, both CrSO2 and RrSO2 returned to normal levels after hypovolemia. Blood pressure management with phenylephrine returned CrSO2 levels to normal, but RrSO2 levels remained significantly lower compared to the pre-hemorrhage values (P < .0001). Comparison of the percent CrSO2 as a function of MAP showed that CrSO2 levels approach baseline when a normal MAP is reached during volume resuscitation. In contrast, a significantly higher MAP was required to return to baseline CrSO2 during blood pressure management with phenylephrine (P < .0001). Evaluation of carotid blood flow and CrSO2 indicated that during induction of hypovolemia, the two measures are strongly correlated. In contrast, there was limited correlation between carotid blood flow and CrSO2 during blood infusion. This study demonstrated that it is possible to restore CrSO2 by manipulating MAP with vasoconstriction, even in profound hypotension. However, MAP manipulation may result in unintended consequences for other organs, such as the kidney, if the tissue is not reoxygenated sufficiently. The clinical implications of these results and how best to respond to hypovolemia in the pre-hospital and hospital settings should be elucidated by additional studies.

Abstract 185: Regional Oxygen Saturation and Capnography Monitoring During Resuscitation After Cardiac Arrest in a Swine Pediatric ARDS Model

Introduction: Survival and outcomes after cardiac arrest (CA) depend largely on the effectiveness of cardiopulmonary resuscitation (CPR). Traditional invasive methods of monitoring CPR can be challenging out-of-hospital and are lacking in more than 50% of in-hospital pediatric CA. Regional oxygen saturation (rSO 2 ) monitoring with Near Infrared Spectroscopy (NIRS) and volumetric capnography offers a noninvasive approach that could potentially overcome these challenges. Aim: To determine the feasibility and effectiveness of NIRS and volumetric capnography monitoring in a swine model of pediatric hypoxia induced CA. Approach: Juvenile pigs were sedated and mechanically ventilated. Mild to moderate Acute Respiratory Distress Syndrome (ARDS) was induced by continuous oleic acid infusion. Respiratory and hemodynamic variables were monitored using invasive and noninvasive (NIRS and capnography) monitoring to assess efficacy of CPR. Animals were randomized into one of the two groups: High-quality CPR (hqCPR) to achieve coronary perfusion pressure of 25-30 mmHg and low-quality CPR (lqCPR) to achieve coronary perfusion pressure of 10-15 mmHg. Trajectories over time were analyzed using regression analyses. The discriminatory ability to distinguish between groups based on trajectories were analyzed using receiver operating characteristics curve (ROC) analysis. Results: 39 animals (23±3 kg) were included in our study. In the hqCPR group, there are generally higher values for cerebral and renal rSO 2 , ETCO 2 , volume of CO 2 elimination (VCO 2 ), and carotid blood flow, compared to the lqCPR group (p&lt;0.0001). Cerebral and renal rSO 2 values increase over time, while ETCO 2 , VCO 2 , and carotid flow values decrease in the hqCPR group. Cerebral rSO2 had a ROC AUC of 0.76 (95% CI: 0.58-0.94), whereas renal rSO2 had a ROC AUC of 0.54 (95% CI: 0.22-0.87) representing nearly no discrimination ability. ETCO 2 had a ROC AUC of 0.66 (95% CI: 0.49-0.84), whereas VCO 2 had a ROC AUC of 0.62 (95% CI: 0.38-0.85). Conclusions: Higher mean cerebral rSO2 values during CPR might be used to assess quality of CPR effectiveness and provide real-time adjustments as needed. This could guide healthcare providers in optimizing CPR quality and improving outcomes for cardiac arrest patients.

The effect of intraoperative cerebral oxygen desaturations on postoperative cerebral oxygen metabolism in neonates and infants a pilot study.

Cerebral oxygen desaturation during pediatric surgery has been associated with adverse perioperative outcomes. The aim of this pilot study was to analyze the frequency and severity of intraoperative cerebral oxygen desaturations and their impact on postoperative cerebral oxygen metabolism in neonates and infants undergoing pediatric surgery. In a prospective pilot study, intra- and postoperative regional cerebral oxygen saturation and blood flow were measured noninvasively using a device combining laser Doppler flowmetry and white-light-spectrometry. Thirty-seven consecutive neonates and infants undergoing noncardiac surgery under general anesthesia for more than 30 min and necessity for invasive arterial blood pressure monitoring were included. Patients with pre-known congenital structural heart disease or cerebral disease were excluded. Continuously brain monitor recording was started in sedated patients before induction of anesthesia (preoperative baseline) and was completed 1 h postoperatively in the PICU in sedated, intubated, and mechanically ventilated states at the PICU (postoperative state). Baseline and postoperative state for cerebral fractional tissue oxygen extraction and approximated cerebral metabolic rate of oxygen were calculated. Seventeen (46%) of the 37 studied neonates and infants suffered from intraoperative periods of regional cerebral oxygen desaturation below 20% of the baseline (event group). Severity of cerebral desaturations was median 4.0%min/h [range 0.1-58.7; interquartile range [IQR] 0.99-21.29]. In the event group, the duration of surgery was significantly longer (median 135 min [range 11-260; IQR 113.5-167.0] vs median 46.5 min [range 11-180; IQR 30.5-159.3]; difference of -62.94; 95% confidence interval [CI] -105.17 to -20.71; p = .021). In the event group, cerebral fractional tissue oxygen extraction (median 0.41 [range 0.20-0.55; IQR 0.26-0.44] vs. median 0.27 [range 0.11-0.41; IQR 0.20-0.31]; difference of -0.11; 95% CI -0.17 to -0.05; p = .001) and approximated cerebral metabolic rate of oxygen (median 6.15 arbitrary unit [range 2.69-12.07; IQR 5.12-7.21] vs. median 4.14 arbitrary unit [range 1.78-7.86; IQR 3.82-6.31]; difference of -1.76; 95% CI -3.03 to -0.49; p = .009) were significantly higher and the cerebral regional oxygen saturation (median 58.99% [range 44.87-79.1; IQR 54.26-72.61] vs median 70.94% [range 57.9-86.13; IQR 67.07-76.59]; difference of 10.01; 95% CI 4.13-15.90; p = .002) significantly lower after surgery compared to the nonevent group. The increase of approximated cerebral metabolic rate of oxygen could indicate an elevated oxidative energy metabolism in the "stressed" brain, due to repair processes. The increased cerebral fractional tissue oxygen extraction fits with the decreased NIRS cerebral oxygenation. Our data suggest that an increase in cerebral oxygen metabolism was the cause. Cerebral oxygen desaturation during major surgery in neonates and infants is associated with early postoperative increased cerebral oxygen extraction and possibly increased cerebral oxygen metabolism.

Abstract 14998: Assessment of Microcirculatory Dysfunction by Measuring Subcutaneous Tissue Oxygen Saturation Using Near-Infrared Spectroscopy in Patients With Circulatory Failure

Background: Patients with circulatory failure have been treated with the goal of normalizing systemic hemodynamic parameters such as blood pressure, central venous pressure, urine output, and central venous oxygen saturation. However, microcirculatory dysfunction remains even after improvement of these indices, suggesting a loss of hemodynamic coherence between the macrocirculation and the microcirculation. Recently, the usefulness of near-infrared spectroscopy (NIRS) in assessing the microcirculation has been reported. Aim: We measure regional tissue oxygenation saturation (rSO 2 ) at 3 - 5 mm subcutaneously in patients with circulatory failure using a finger-mounted tissue oximeter with the NIRS technique (Toccare: Astem Co., Ltd., Kawasaki, Japan) to investigate its relationship with microcirculation. Methods: This is a single-center prospective observational cohort study of patients with circulatory failure (systolic blood pressure ≤ 90 mmHg or lactate ≥ 2 mmol/L at presentation) transported to the emergency department of Nihon University Hospital from 15 June 2020 to 31 March 2022. We measured rSO 2 in the forehead, thenar eminence, thumb and knee using Toccare and assessed the relationship between rSO 2 and blood pressure, acute physiology and chronic health evaluation (APACHE) II score, sequential organ failure assessment (SOFA) score and mottling score. Result: In patients with circulatory failure (n = 38), rSO 2 at each site showed no correlation with blood pressure, a negative correlation with SOFA score and APACHE II score and a positive correlation with mottling score. These significant correlations were also best observed in the knee. Conclusion: In patients with circulatory failure, rSO 2 measured with Toccare showed no correlation with blood pressure but a significant negative correlation with the severity of organ damage. The knee is possibly the optimal measurement site for monitoring microcirculatory dysfunction and determining the effectiveness of treatment.

Differences in Cerebral Tissue Oxygenation in Preterm Neonates Receiving Adult or Cord Blood Red Blood Cell Transfusions

Repeated transfusions in preterm neonates with anemia of prematurity replace fetal hemoglobin (HbF) with adult Hb (HbA), which has a low oxygen affinity. The reduction of HbF is associated with a higher incidence of retinopathy of prematurity (ROP). To assess whether HbF and HbA are differently associated with cerebral tissue oxygenation in preterm neonates. This cohort study was a single-center, pilot study on cerebral oxygenation kinetics in preterm neonates with a gestational age between 24.0 weeks and 27.9 weeks who were admitted to the neonatal intensive care unit of Policlinico Universitario A. Gemelli IRCCS from December 27, 2021, to May 15, 2023. This study was ancillary to the ongoing, double-blind, multicenter Umbilical or Adult Donor Red Blood Cells in Extremely Low Gestational Age Neonates and Retinopathy of Prematurity (BORN) randomized clinical trial. The BORN trial outcome was ROP severity in neonates randomized to receive standard packed red blood cell (PRBC) transfusions obtained from RBCs of adult donors (A-RBCs) or from cord blood (CB-RBCs). According to standard procedures at the institute's neonatal intensive care unit, patients concurrently received continuous cerebral near-infrared spectroscopy (NIRS) monitoring. This cohort study was not prespecified in the trial protocol. Transfusion with A-RBCs or CB-RBCs. The main outcome was the kinetics of cerebral regional oxygen saturation (crSO2) and cerebral fraction of tissue oxygen extraction (cFTOE) associated with A-RBC or CB-RBC transfusions. Cerebral NIRS monitoring was performed by neonatologists and nurses, who were blinded to the PRBC type. The NIRS monitoring was conducted starting with the blood product order, during transfusion, and for the subsequent 24 hours after transfusion completion. The mean treatment effects of A-RBCs or CB-RBCs were quantified using a linear mixed model for repeated measures. Of 23 randomized neonates, 17 (11 male [64.7%]; median gestational age at birth, 25.6 weeks [IQR, 25.3-26.1 weeks]) with a median birth weight of 840 g (IQR, 580-900 g) were included in the study; NIRS was evaluated for 42 transfusion episodes, of which 22 were A-RBCs and 20 were CB-RBCs. Globally considering all posttransfusion time points, the overall crSO2 covariate-adjusted mean after CB-RBC transfusions was 5.27% lower (95% CI, 1.20%-9.34%; P = .01) than that after A-RBC transfusions, while the cFTOE after CB-RBC transfusions was 6.18% higher (95% CI, 1.66%-10.69%; P = .009) than that after A-RBCs. The findings of this cohort study suggest that A-RBC transfusions may be associated with more oxygen delivery to cerebral tissues of preterm neonates than transfusions from CB-RBCs. This finding may explain the previously observed association between low HbF and high ROP risk. It also suggests that use of CB to meet the RBC transfusion needs of neonates with a gestational age of less than 28 weeks may protect cerebral tissues from overexposure to oxygen.

Near-Infrared Spectroscopy for Continuous Noninvasive Monitoring of Free Flap in Head and Neck Reconstruction: Systematic Review of the Literature and Personal Experience.

Buried free flaps represent a reconstructive challenge concerning monitoring of vitality, which is fundamental for an early detection of flap failure and prompt surgical salvage. Many flap monitoring techniques have been developed over time, and there is still no consensus concerning the best monitoring technique for buried reconstructions. We performed a systematic review of the literature on NIRS monitoring for head and neck free flaps. Moreover, we presented a case of orbital reconstruction through a buried free myo-fascial anterolateral tight flap (ALTF) in which postoperative monitoring was performed by means of NIRS. Four studies were included with a total of 200 monitored head and neck free flap reconstructions. Flap survival was reported in 96.5% of studies (n = 193/200) with a 3.5% of total flap failure rate (n = 7/200). We monitored the buried myo-fascial ALTF for 7 post-operative days measuring a regional oxygen saturation (rSO2) ranging from 55% to 72% (mean = 66%). This device appeared to be an efficient choice for monitoring buried flaps, thanks to its ability to measure tissue perfusion deep under the skin, to the continuous availability of recorded data on the monitor, and to its low impact on the patient. Further prospective studies are advised in order to standardize this monitoring technique and define warning values.

Cerebral and intestinal oxygen saturation of different volumes of red blood cell transfusion in preterm infants

ObjectivesThe purpose of this study was to investigate and compare the effects of 20 ml/kg and 15 ml/kg red blood cell transfusion (RBCT) on cerebral and intestinal tissue oxygenation, the number of administered transfusions, and neonatal complications in premature infants with anemia. MethodsThis prospective, randomized, partially blinded observational study investigated anemic neonates of gestational age < 32 weeks (Registration ID: ChiCTR 1,900,026,672). The infants were randomly assigned to receive 15 or 20 ml/kg red blood cell transfusion. Cerebral and intestinal tissue oxygen saturation (cer rSO2 and int rSO2) were collected 2 h before transfusion, 2, 4, 6, 12, 24, and 48 h after the beginning of transfusion by Near-infrared spectroscopy (NIRS). We also collected vital signs including heart rate (HR), peripheral oxygen saturation (SpO2), and mean arterial blood pressure (MABP) 2 h before infusion, 2 h, and 6 h after the beginning of transfusion. Then we analyzed and compared regional oxygen saturation(rSO2), fractional tissue oxygen extraction (FTOE), and other outcome readouts (blood transfusion numbers, changes in hematocrit and hemoglobin, hospitalization days, HR, SpO2, MABP, and complications) between the two groups. The intraindividual comparisons of the above readouts before transfusion and those after transfusion were also evaluated within each group. Result73 newborns received 20 ml/kg (large volume group) and 78 newborns received 15 ml/kg transfusion (small volume group). There was no significant difference in cer rSO2, int rSO2, Cerebral fractional tissue oxygen extraction (cFTOE), and intestinal fractional tissue oxygen extraction (iFTOE) between the two groups. rSO2, MABP, and SpO2 increased; HR, cFTOE, and iFTOE decreased following transfusion in both groups. The transfusion number of the large volume group is significantly less than that of the small volume group (1.9 ± 0.3 vs. 2.6 ± 0.9, p < 0.01) and hospitalization days were also less than those in the low volume group (44.3 ± 8.2 vs. 47.6 ± 9.8, p < 0.05). The increases in hematocrit and hemoglobin were higher in the large volume group than those in small volume (hematocrit increment (%),10.7 ± 4.2 vs. 10.1 ± 5.9, p = 0.015; Hb concentration after blood transfusion (g/L) 132.3 ± 11.1 vs. 127.4 ± 15.4, p = 0.028). ConclusionAfter the transfusion, cer rSO2 and int rSO2 increased significantly, FTOE decreased and vital signs improved in both the 15 ml/kg and 20 ml/kg groups, and these changes were not significantly different between the two groups. However, the larger group showed a more pronounced increase in hematocrit and hemoglobin, a reduction in the total number of transfusions, and a shorter duration of hospitalization after transfusion in preterm infants without increasing complications.

DIAGNOSTIC VALUE OF ADDITIONAL MARKERS FOR ACUTE KIDNEY INJURY IN PRETERM NEONATES WITH PATENT DUCTUS ARTERIOSUS

DIAGNOSTIC VALUE OF ADDITIONAL MARKERS FOR ACUTE KIDNEY INJURY IN PRETERM NEONATES WITH PATENT DUCTUS ARTERIOSUS

154. EVALUATION OF BLOOD FLOW IN RECONSTRUCTED GASTRIC TUBE AND IDENTIFICATION OF OPTIMAL ANASTOMOSES IN ESOPHAGECTOMY

Abstract Background Anastomotic leakage in esophageal cancer surgery may be reduced by the evaluated blood flow to the reconstructed organ, but it is difficult to evaluate quantitatively arterial and venous blood flow. This study aimed to evaluate quantitatively blood flow that has not been possible before, and to determine the relationship between the blood flow in the gastric tube with anastomosis leakage using near-infrared spectroscopy. Methods This single-center, observational study included 50 patients aged 51 to 82 who underwent radical esophagectomy with gastric tube reconstruction for esophageal cancer from June 2022 and January 2023. Regional tissue oxygen saturation was measured at the antrum (point X), the anastomotic point (point Z), and the midpoint between points X and Z (point Y) before and after gastric tube formation. These, alongside the decreasing rate of oxygen saturation at the three points, were investigated in relation to anastomosis leakage. Results Regional tissue oxygen saturation at points X and Z after gastric tube formation was significantly lower in the presence of leakage than in its absence. The decreasing rate of regional tissue oxygen saturation at point Z was significantly higher in the presence of leakage than in its absence. There was no significant difference in the decreasing rate of regional tissue oxygen saturation at point X and Y between the presence and absence of leakage. The cut-off decreasing rate of the rSO2 was 29.4%. Conclusion Regional tissue oxygen saturation levels may be useful for measuring blood flow and may be a predictor of anastomosis leakage.

The diagnostic value of pulmonary near-infrared spectroscopy in the early distinction of neonatal pneumonia from transient tachypnea of the newborn.

Pulmonary near-infrared spectroscopy (NIRS) is a new and promising tool for diagnosis of neonatal respiratory diseases (RD). The study aimed to determine the role of pulmonary regional oxygen saturation (pRSO2 ) values obtained by NIRS in the early distinction of neonatal pneumonia (NP) from transient tachypnea of the newborn (TTN). This prospective, observational, double-blind study was conducted in neonatal intensive care unit (NICU) between 2020 and 2021. Late preterm and term newborns hospitalized in the NICU due to the diagnosis of TTN and NP were included. Cerebral RSO2 and pRSO2 values were measured during the 1st, 24th, 48th, and 72nd hours of hospitalization, using NIRS. Of the eligible 40 infants, 65% (n: 26) were diagnosed as TTN and 35% (n: 16) as NP. The pRSO2 values were significantly higher in the TTN group than the NP group for both apexes (75.3 ± 8.7 vs. 69 ± 5.4, p: .018, respectively) and lateral lung (77.8 ± 6 vs. 72.7 ± 6.2, p: .016, respectively) in the 1st hour of hospitalization. There were significant differences in pRSO2 apex and pRSO2 lateral values between the 1st and 24th hours of hospitalization and the 24th and 48th hours in the NP group (p2 : .001 for both). The optimal pRSO2 apex cut-off value was >72% to predict the diagnosis of NP with a sensitivity of 78.6% and a specificity of 69.2%. Pulmonary NIRS may be considered as a feasible and promising diagnostic tool in late preterm and term infants with RD. It may also be helpful for the early differentiation of NP from TTN and the courses of these diseases.

Comparison of the SenSmart™ and the INVOS™ neonatal cerebral near-infrared spectrometry devices.

To determine the correlation and agreement between the SenSmart™ and the INVOS™ devices of neonatal cerebral regional oxygen saturation (CrSO2) measurements using neonatal sensors. The secondary objective was to develop a regression model that predicts CrSO2-INVOS values using CrSO2-SenSmart indices and determine whether the values between the devices are interchangeable. A prospective, cross-sectional study was conducted in infants during the first 4 weeks of life. Simultaneous, bilateral CrSO2 was measured using the SenSmart™X100 (CrSO2-SenSmart) or INVOS™ 5100C (CrSO2-INVOS) device in each frontoparietal area for 2 h. Five-minute CrSO2 values were extracted for analysis. Thirty infants were recruited with 720 pairwise measurements and 26 (84%) were evaluated in the first week of life. Mean gestational age of the preterm and term infants was [30.9 ± 2.8 (n = 14) and 38.8 ± 1.1 (n = 16)] weeks, respectively. Overall CrSO2- was 77.08 ± 9.70% and 71.45 ± 12.74% for the SenSmart and INVOS, respectively (p < 0.001). The correlation coefficient (r) between the CrSO2-SenSmart and INVOS was 0.20 (p < 0.001). The mean difference between the CrSO2-SenSmart and INVOS was 5.63 ± 13.87% with -21.6% to 32.8% limits of agreement. The r and mean difference was 0.39 (p < 0.001) and 8.87 ± 12.58% in preterm infants, and 0.06 (p = 0.27) and 2.79 ± 14.34 in term infants. The CrSO2-SenSmart tended to read higher than the CrSO2-INVOS device. There was no correlation between the CrSO2-SenSmart and the CrSO2-INVOS in term infants and it was weak in preterms. Due to imprecise agreement, the CrSO2-SenSmart values are not interchangeable with those of the CrSO2-INVOS.

The effects of mydriatic eye drops on cerebral blood flow and oxygenation in retinopathy of prematurity examinations.

Mydriatic eye drops used during retinopathy examination have been associated with cardiovascular, respiratory, and gastrointestinal side effects. The aim of our study was to investigate the effects of the drops used for pupil dilatation on cerebral blood flow and cerebral oxygenation. The study included 62 infants who underwent retinopathy screening exams. Vital signs, heart rate (HR), arterial oxygen saturation (SpO2), and mean arterial pressure (MAP) were recorded. Cerebral oxygenation and middle cerebral artery blood flow velocity were evaluated using near-infrared spectroscopy (NIRS) and Doppler ultrasonography, respectively, and the cerebral metabolic rate of oxygen (CMRO2) was also calculated. The mean gestational age of the infants included was 31.29 ± 1.42weeks, and the mean birth weight was 1620 ± 265g. Heart rate was found to be significantly decreased after mydriatic eye drop instillation; however, there were no significant differences regarding blood pressure and oxygen saturation levels (HR: p < 0.001; MAP: p = 0.851; SpO2: p = 0.986, respectively). After instillation while cerebral regional oxygen saturation (rScO2) measurements were significantly decreased at the 60th minute (p = 0.01), no significant difference was found in Vmax and Vmean of MCA before and after mydriatic eye drop instillation (p = 0.755, p = 0.515, respectively). Regarding CMRO2 measurements, we also did not find any statistical difference (p = 0.442). Conclusion:Our study has shown that although eye drops may affect heart rate and regional cerebral oxygen saturation, they do not alter cerebral blood flow velocities and metabolic rate of oxygen consumption. Current recommendations for mydriatic eye drop use in retinopathy exam appear to be safe. What is Known: • Mydriatic eye drop installation is recommended for pupil dilatation during ROP screening exams. • It's known that mydriatics used in ROP examination have affects on the vital signs, cerebral oxygenation and blood flow. What is New: • This is the first study evaluating the changes in cerebral oxygenation and blood flow velocity after mydriatic drop instillation using NIRS and Doppler US concomitantly. • While the eye drops may affect heart rate and regional cerebral oxygen saturation, they do not alter cerebral blood flow velocities and metabolic rate of oxygen consumption.

Trends on Near-Infrared Spectroscopy Associated With Acute Brain Injury in Venoarterial Extracorporeal Membrane Oxygenation.

We aimed to determine the association between cerebral regional oxygen saturation (rSO 2 ) trends from cerebral near-infrared spectroscopy (cNIRS) and acute brain injury (ABI) in adult venoarterial extracorporeal membrane oxygenation (VA-ECMO) patients. ABI was defined as intracranial hemorrhage, ischemic stroke, hypoxic ischemic brain injury, or brain death during ECMO. rSO 2 values were collected from left and right cerebral oximetry sensors every hour from ECMO cannulation. Cerebral desaturation was defined as consecutive hours of rSO 2 < 40%. rSO 2 asymmetry was determined by (a) averaging left/right rSO 2 difference over the entire ECMO run; (b) consecutive hours of rSO 2 asymmetry. Sixty-nine VA-ECMO patients (mean age 56 years, 65% male) underwent cNIRS. Eighteen (26%) experienced ABI. When the mean rSO 2 asymmetry was >8% there was significantly increased odds of ABI (aOR = 39.4; 95% CI = 4.1-381.4). Concurrent rSO 2 < 40% and rSO 2 asymmetry >10% for >10 consecutive hours (asymmetric desaturation) was also significantly associated with ABI (aOR = 5.2; 95% CI = 1.2-22.2), but neither criterion alone were. Mean rSO 2 asymmetry>8% exhibited 39% sensitivity and 98% specificity for detecting ABI, with an area under the curve (AUC) of 0.86, and asymmetric desaturation had 33% sensitivity and 88% specificity, with an AUC of 0.72. These trends on NIRS monitoring may help detect ABI in VA-ECMO patients.

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.

Pain-related changes in crSO2 among premature infants undergoing PICC insertion

Objective To evaluate the effectiveness of cerebral regional oxygen saturation (crSO2) values, measured using near-infrared spectroscopy (NIRS), in assessing pain associated with the peripherally inserted central catheter (PICC) in premature infants. Methods NIRS was used to measure the crSO2 levels of 48 premature infants with gestational age (GA) of < 32 weeks or a birth weight of < 1500 g. Premature infant pain profile (PIPP) scores, vital signs, transcutaneous oxygen tension (TcpO2), transcutaneous carbon dioxide tension (TcpCO2), and crSO2 values were monitored. One-way repeated measure analysis of variance was used to compare heart rate (HR), respiratory rate (RR), blood pressure (BP), peripheral oxygen saturation (SpO2), TcpO2, TcpCO2, and crSO2 values before (Time 1), during (Time 2), and after (Time 3) PICC insertion. The correlation between the PIPP scores at Time 2 and the fluctuations (values detected at Time 2 minus those at Time 1) of SpO2, TcpO2, and crSO2 were also analyzed. Results The PIPP score at Time 2 was significantly higher than those at Times 1 and 3. HR, RR, and BP values increased (p < .05), and SpO2 and crSO2 levels decreased at Time 2 (p < .05) compared with those at Time 1. Stratified analysis based on GA revealed significant differences in HR, RR, and crSO2 values between Times 1 and 2 in infants with a GA of ≥ 32 weeks. In infants with a GA < 32 weeks, significant differences were observed in HR, RR, SpO2, BP, and crSO2 values between Times 1 and 2. The fluctuation of the crSO2 level was strongly correlated with the PIPP score at Time 2 (r = −0.829, p < .001). A weak correlation was observed between the PIPP score at Time 2 and TcpO2 level fluctuation (r = 0.375, p = .009). No correlation was observed between the PIPP score at Time 2 and SpO2 level fluctuation (r = 0.242, p = .097). Conclusion The fluctuation of crSO2 levels strongly correlates with PICC procedural pain. Hence, crSO2 levels measured using NIRS may be used as an indicator for pain assessment in premature infants.

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.

Changes in Cerebral Regional Oxygen Saturation Variability in Neonates Undergoing Cardiac Surgery: A Prospective Cohort Study.

Near-infrared spectroscopy is routinely used in the monitoring of cerebral regional oxygen saturation (crSO2) in neonates following congenital heart surgery. Decreased postoperative crSO2 variability in these patients is associated with worse clinical outcomes, including neurodevelopmental outcomes. We sought to explore changes in crSO2 variability between the preoperative and postoperative periods and associations with short-term clinical outcomes in neonates undergoing cardiac surgery. We performed a prospective cohort study of neonates undergoing cardiac surgery with cardiopulmonary bypass between November 2019 and May 2021. We calculated crSO2 variability using averaged 1min of crSO2 values for a minimum of 12h before, and the first 48h following surgery. 37 neonates (median age at start of monitoring 4days (interquartile range 2-5days)) were included in our study. We observed a 30% decrease in crSO2 variability between the preoperative and postoperative monitoring periods (p < 0.001). Preoperative crSO2 variability increased by 9% (p = 0.009) for each additional postnatal day. There were no associations between the degree of decrease in crSO2 variability postoperatively and class of cardiac lesion (e.g., aortic arch obstruction, single ventricle physiology) or short-term postoperative clinical outcomes. There was a significant decrease in postoperative crSO2 variability following neonatal cardiac surgery as compared to the preoperative period, likely influenced by several factors. The impact of interventions on crSO2 variability and resultant influence on long-term outcomes, such as neurodevelopmental outcomes, requires further exploration.

The Diagnostic Value of Near-Infrared Spectroscopy to Predict Delayed Cerebral Ischemia and Unfavorable Outcome After Subarachnoid Hemorrhage

Near-infrared spectroscopy (NIRS) is a noninvasive tool to monitor cerebral regional oxygen saturation. Impairment of microvascular circulation with subsequent cerebral hypoxia during delayed cerebral ischemia (DCI) is associated with poor functional outcome after subarachnoid hemorrhage (SAH). Therefore, NIRS could be useful to predict the risk for DCI and functional outcome. However, only limited data are available on NIRS regional cerebral tissue oxygen saturation (rSO2) distribution in SAH. The aim of this study was to compare the distribution of NIRS rSO2 values in patients with nontraumatic SAH with the occurrence of DCI and functional outcome at 2 months. In addition, the predictive value of NIRS rSO2 was compared with the previously validated SAFIRE grade (derived from Size of the aneurysm, Age, FIsher grade, World Federation of Neurosurgical Societies after REsuscitation). In this study, the rSO2 distribution of patients with and without DCI after SAH was compared. The optimal cutoff points to predict DCI and outcome were assessed, and its predictive value was compared with the SAFIRE grade. Of 41 patients, 12 developed DCI, and 9 had unfavorable outcome at 60 days. Prediction of DCI with NIRS had an area under the curve of 0.77 (95% confidence interval 0.62-0.92; P= 0.0028) with an optimal cutoff point of 65% (sensitivity 1.00; specificity 0.45). Prediction of favorable outcome with NIRS had an area under the curve of 0.86 (95% confidence interval 0.74-0.98; P= 0.0003) with an optimal cutoff point of 63% (sensitivity 1.00; specificity 0.63). Regression analysis showed that NIRS rSO2 score is complementary to the SAFIRE grade. NIRS rSO2 monitoring in patients with SAH may improve prediction of DCI and clinical outcome after SAH.

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.