Cerebral Fractional Tissue Oxygen Extraction Research Articles

Coupling between Regional Oxygen Saturation of the Brain and Vital Signs during Immediate Transition after Birth

Introduction: The primary aim was to analyze any coupling of heart rate (HR)/arterial oxygen saturation (SpO₂) and regional cerebral oxygen saturation (rScO₂) and regional cerebral fractional tissue oxygen extraction (cFTOE) during immediate transition after birth in term and preterm neonates to gain more insight into interactions. Methods: The present study is a post hoc analysis of data from 106 neonates, obtained from a prospective, observational study. Measurements of HR, SpO₂, rScO₂, and cFTOE were performed during the first 15 min after birth. The linear and nonlinear correlation were computed between these parameters in a sliding window. The resulting coupling curves were clustered. After clustering, demographic data of the clusters were de-blinded and compared. Results: Due to missing data, 58 out of 106 eligible patients were excluded. Two clusters were obtained: cluster 1 (N = 39) and cluster 2 (N = 9). SpO₂ had linear and nonlinear correlations with rScO₂ and cFTOE, whereby the correlations with rScO₂ were more pronounced in cluster 2. HR-rScO₂ and HR-cFTOE demonstrated a nonlinear correlation in both clusters, again being more pronounced in cluster 2, whereby linear correlations were mainly absent. After de-blinding, the demographic data revealed that the neonates in cluster 2 had significantly lower gestational age (mainly preterm) compared to cluster 1 (mainly term). Discussion: Besides SpO₂, also HR demonstrated a nonlinear correlation with rScO₂ and cFTOE in term and preterm neonates during immediate transition after birth. In addition, the coupling of SpO₂ and HR with cerebral oxygenation was more pronounced in neonates with a lower gestational age.

Ventilatory Support, Extubation, and Cerebral Perfusion Changes in Pre-Term Neonates: A Near Infrared Spectroscopy Study.

Early extubation is considered to be beneficial for pre-term neonates. On the other hand, premature extubation can cause lung derecruitment, compromised gas exchange, and need for reintubation, which may be associated with severe brain injury caused by sudden cerebral blood flow changes. We used near infrared spectroscopy (NIRS) to investigate changes in cerebral oxygenation (rScO2) and fractional tissue oxygen extraction (+) after extubation in pre-term infants. This is a single-center retrospective study of NIRS data at extubation time of all consecutive pre-term neonates born at our institution over a 1-year period. Comparison between subgroups was performed. Nineteen patients were included; average gestational age (GA) was 29.4 weeks. No significant change was noted in rScO2 and cFTOE after extubation in the whole population. GA and germinal matrix hemorrhage (GMH)-intraventricular hemorrhage (IVH) showed a significant change in rScO2 and cFTOE after extubation. A significant increase in cFTOE was noted in patients with previous GMH-IVH (+0.040; p = 0.05). To conclude, extubation per se was not associated with significant change in cerebral oxygenation and perfusion. Patients with a diagnosed GMH-IVH showed an increase in cFTOE, suggesting perturbation in cerebral perfusion suggesting further understanding during this challenging phenomenon. Larger studies are required to corroborate our findings.

Changes in regional tissue oxygen saturation values during the first week of life in stable preterm infants.

Near infrared spectroscopy (NIRS) is a non-invasive method for monitoring regional tissue oxygen saturation (rSO2). The purpose of this study is to investigate the changes that occur in cerebral, splanchnic, and renal rSO2 and fractional tissue oxygen extraction (FTOE) in stable preterm infants in the first week of life. Prospective observational study of infants born 30-34weeks gestation at NYU Langone Health between November 2017 and November 2018. Cerebral, renal, and splanchnic rSO2 were monitored from 12 to 72 h of life, andatseven days. Subjects were divided into gestational age(GA) cohorts. Average rSO2, splanchnic cerebral oxygen ratio(SCOR), FTOE, and regional intra-subject variability was calculated at each location at five different time intervals: 0-12 h, 12-24 h, 24-48 h, 48-72 h, and one week of life. Twenty subjects were enrolled. The average cerebral rSO2 ranged from 76.8 to 92.8 %, renal rSO2 from 65.1 to91.1 %, and splanchnic rSO2 from 36.1 to 76.3 %. The SCOR ranged from 0.45 to 0.94. The strongest correlation between the GA cohorts was in the cerebral region (R2=0.94) and weakest correlation was in the splanchnic region (R2=0.81). The FTOE increased in all three locations over time. Intra-subject variability was lowest in the cerebral region (1.3 % (±1.9)). The cerebral region showed the strongest correlation between GA cohorts and lowest intra-subject variability, making it the most suitable for clinical use whenmonitoring for tissue hypoxia. Further studies are needed to further examine rSO2 in preterm infants.

Reference Ranges for Regional Cerebral Oxygen Saturation with Masimo O3® after Birth and Differences with Other Devices.

Cerebral oximetry using near-infrared spectroscopy (NIRS) is a noninvasive optical technology widely used in neonatology. The present study aimed to define reference ranges for cerebral tissue oxygen saturation (crSO2) with a new four-wavelength NIRS device, Masimo O3® oximeter, during immediate transition after birth and compare values with those obtained previously with NIRO 200NX®. This was a prospective observational study using Masimo O3 device to measure crSO2 and regional cerebral fractional tissue oxygen extraction (cFTOE) in healthy term newborns delivered by primary cesarean section, during the 15 minutes after cord clamping. The neonates who required any medical support were excluded. The NIRS sensor was placed on the right forehead. Peripheral oxygen saturation and heart rate were continuously measured by pulse oximetry. Previous studies which established centiles for crSO2 with NIRO 200NX were used for comparison. A total of 44 newborns were included. The median crSO2 and cFTOE (interquartile range) at 2, 5, and 7 minutes was 54% (49-54), 71% (64-86), and 79% (73-84) and 0,25 (0,18-0,33), 0,19 (0,15-0,23), and 0,16 (0,12-0,21), respectively, with no further changes afterwards. The crSO2 measurements were significantly higher with Masimo O3 compared with NIRO-200NX. The present observational study presented reference ranges for crSO2 and cFTOE measured with Masimo O3 oximeter during the immediate neonatal transition. Values obtained with O3 were higher than those obtained with other oximeters. For this reason, crSO2 is device-specific so there must be known reference values for each oximeter to define therapeutic interventions based on crSO2 and assess cerebral oxygenation in clinical studies. · Masimo O3 uses four wavelengths to measure regional oxygen saturation value.. · O3 values of crSO2 and cFTOE differ with other neonatal oximeters at birth.. · Knowledge of reference range of O3 at birth is essential to guide resuscitation..

Evaluation of cerebral autoregulation of oxygen by NIRS method during postnatal transition period in term and late preterm newborns without resuscitation requirement.

Pulse oximetry is commonly used to monitor arterial oxygen saturation and heart rate during the transition period and reference intervals have been determined. However, the effect of the change in arterial oxygen saturation on tissue oxygenation does not seem to be the same. So, a non-invasive method for monitoring cerebral or regional tissue oxygenation will be potentially useful for vulnerable infants. This study aims to evaluate the effectiveness of cerebral autoregulation in the first 10 min after delivery in term and late preterm newborns without resuscitation requirement. Cerebral tissue oxygen saturation was measured in the first 10 min after birth with near-infrared spectroscopy (NIRS) from the left forehead. Peripheral oxygen saturation was measured with pulse oximetry from the right hand and cerebral fractional tissue oxygen extraction was calculated. Nineteen late preterms and 20 term infants were included in the study. There was no statistically significant difference between median cerebral tissue oxygen saturation and cerebral fractional tissue oxygen extraction values of late preterm and term infants (p < 0.001). There was a strong inverse relationship between cerebral tissue oxygen saturation and cerebral fractional tissue oxygen extraction (p < 0.001). In late preterm infants similar to term infants, arterial oxygen saturation and cerebral tissue oxygen saturation increased with time, but inverse reduction of cerebral fractional tissue oxygen extraction showed the presence of an active autoregulation in the brain. This can be interpreted as the ability of the brain to protect itself from hypoxia by regulating oxygen uptake during normal fetal-neonatal transition process. A larger scale multi-center randomized control trial is now needed to further inform practice.

Cerebrovascular responses to a 90° tilt in healthy neonates.

Tilts can induce alterations in cerebral hemodynamics in healthy neonates, but prior studies have only examined systemic parameters or used small tilt angles (<90°). The healthy neonatal population, however, are commonly subjected to large tilt angles (≥90°). We sought to characterize the cerebrovascular response to a 90° tilt in healthy term neonates. We performed a secondary descriptive analysis on 44 healthy term neonates. We measured cerebral oxygen saturation (rcSO2), oxygen saturation (SpO2), heart rate (HR), breathing rate (BR), and cerebral fractional tissue oxygen extraction (cFTOE) over three consecutive 90° tilts. These parameters were measured for 2-min while neonateswere in a supine (0°) position and 2-min while tilted to a sitting (90°) position. We measured oscillometric mean blood pressure (MBP) at the start of each tilt. rcSO2 and BR decreased significantly in the sitting position, whereas cFTOE, SpO2, and MBP increased significantly in the sitting position. We detected a significant position-by-time interaction for all physiological parameters. A 90° tilt induces a decline in rcSO2 and an increase in cFTOE in healthy term neonates. Understanding the normal cerebrovascular response to a 90° tilt in healthy neonates will help clinicians to recognize abnormal responses in high-risk infant populations. Healthy term neonates (≤14 days old) had decreased cerebral oxygen saturation (~1.1%) and increased cerebral oxygen extraction (~0.01) following a 90° tilt. We detected a significant position-by-time interaction with all physiological parameters measured, suggesting the effect of position varied across consecutive tilts. No prior study has characterized the cerebral oxygen saturation response to a 90° tilt in healthy term neonates.

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.

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.

Tissue Oxygenation Changes After Transfusion and Outcomes in Preterm Infants

Preterm infants with varying degrees of anemia have different tissue oxygen saturation responses to red blood cell (RBC) transfusion, and low cerebral saturation may be associated with adverse outcomes. To determine whether RBC transfusion in preterm infants is associated with increases in cerebral and mesenteric tissue saturation (Csat and Msat, respectively) or decreases in cerebral and mesenteric fractional tissue oxygen extraction (cFTOE and mFTOE, respectively) and whether associations vary based on degree of anemia, and to investigate the association of Csat with death or neurodevelopmental impairment (NDI) at 22 to 26 months corrected age. This was a prospective observational secondary study conducted among a subset of infants between August 2015 and April 2017 in the Transfusion of Prematures (TOP) multicenter randomized clinical trial at 16 neonatal intensive care units of the Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network. Preterm neonates with gestational age 22 to 28 weeks and birth weight 1000 g or less were randomized to higher or lower hemoglobin thresholds for transfusion. Data were analyzed between October 2020 and May 2022. Near-infrared spectroscopy monitoring of Csat and Msat. Primary outcomes were changes in Csat, Msat, cFTOE, and mFTOE after transfusion between hemoglobin threshold groups, adjusting for age at transfusion, gestational age, birth weight stratum, and center. Secondary outcome at 22 to 26 months was death or NDI defined as cognitive delay (Bayley Scales of Infant and Toddler Development-III score <85), cerebral palsy with Gross Motor Function Classification System level II or greater, or severe vision or hearing impairment. A total of 179 infants (45 [44.6%] male) with mean (SD) gestational age 25.9 (1.5) weeks were enrolled, and valid data were captured from 101 infants during 237 transfusion events. Transfusion was associated with a significant increase in mean Csat of 4.8% (95% CI, 2.7%-6.9%) in the lower-hemoglobin threshold group compared to 2.7% (95% CI, 1.2%-4.2%) in the higher-hemoglobin threshold group, while mean Msat increased 6.7% (95% CI, 2.4%-11.0%) vs 5.6% (95% CI, 2.7%-8.5%). Mean cFTOE and mFTOE decreased in both groups to a similar extent. There was no significant change in peripheral oxygen saturation (SpO2) in either group (0.2% vs -0.2%). NDI or death occurred in 36 infants (37%). Number of transfusions with mean pretransfusion Csat less than 50% was associated with NDI or death (odds ratio, 2.41; 95% CI, 1.08-5.41; P = .03). In this secondary study of the TOP randomized clinical trial, Csat and Msat were increased after transfusion despite no change in SpO2. Lower pretransfusion Csat may be associated with adverse outcomes, supporting further investigation of targeted tissue saturation monitoring in preterm infants with anemia. ClinicalTrials.gov Identifier: NCT01702805.

Relationship between cerebral oxygenation, cardiac output, and blood pressure during transitional period in extremely low gestational age neonates.

To describe the relationship between cerebral oxygenation, cardiac output, arterial blood pressure (BP), and cerebral blood flow velocity in extremely low gestational age neonates (ELGANs) during transition. This study comprises secondary analyses from a prospective observational study conducted at a tertiary Neonatal Intensive Care Unit. Recruited ELGANs underwent cerebral saturation (CrSO2) monitoring and serial echocardiography during 72 h from birth. Correlative analyses of CrSO2 and cerebral fractional tissue oxygen extraction (CFTOE) with left (LVO) and right ventricular output (RVO), superior vena cava (SVC) flow, middle cerebral artery blood flow mean velocity (MCA.MV), systolic (SBP), diastolic (DBP), and mean (MBP) BP were conducted. Fifty ELGANs with median (range) gestational age of 25.9 (23.1-27.9) weeks were recruited. Echocardiography was performed sequentially at a median (range) age 5.0 (3.8-6.6), 17.3 (15.4-19.4), 31.0 (27.0-34.1), and 53.7 (49.3-58.3) hours. RVO, LVO, CrSO2, and SBP increased over time but no changes in MBP, DBP, CFTOE, MCA.MV or SVC flow were noted. A weak correlation was identified between CrSO2 and SBP (r2 = 0.11, p = 0.047) and MBP (r2 = 0.12, p = 0.04) at 17.3 (15.4-19.4) hours. No correlation of either CrSO2 or CFTOE with any measures of blood flow was identified. There is a weak correlation between measures of cardiac output, BP, and MCA.MV with both CrSO2 and CFTOE in ELGANs during transition. Whether this finding suggests intact cerebral autoregulation requires prospective evaluation in a cohort of sick ELGANs.

Cerebral oxygenation immediately after birth and long-term outcome in preterm neonates—a retrospective analysis

BackgroundPrematurity is associated with increased risk for morbidity and mortality. Aim of this study was to evaluate whether cerebral oxygenation during fetal-to-neonatal transition period was associated with long-term outcome in very preterm neonates.MethodsPreterm neonates ≤ 32 weeks of gestation and/or ≤ 1500 g with measurements of cerebral regional oxygen saturation (crSO2) and cerebral fractional tissue oxygen extraction (cFTOE) within the first 15 min after birth were analysed retrospectively. Arterial oxygen saturation (SpO2) and heart rate (HR) were measured with pulse oximetry. Long-term outcome was assessed at two years using “Bayley Scales of Infant Development” (BSID-II/III). Included preterm neonates were stratified into two groups: adverse outcome group (BSID-III ≤ 70 or testing not possible due to severe cognitive impairment or mortality) or favorable outcome group (BSID-III > 70). As the association between gestational age and long-term outcome is well known, correction for gestational age might disguise the potential association between crSO2 and neurodevelopmental impairment. Therefore, due to an explorative approach the two groups were compared without correction for gestational age.ResultsForty-two preterm neonates were included: adverse outcome group n = 13; favorable outcome group n = 29. Median(IQR) gestational age and birth weight were 24.8 weeks (24.2–29.8) and 760 g (670–1054) in adverse outcome group and 30.6 weeks (28.1–32.0) (p = 0.009*) and 1250 g (972–1390) (p = 0.001*) in the favorable outcome group, respectively. crSO2 was lower (significant in 10 out of 14 min) and cFTOE higher in adverse outcome group. There were no difference in SpO2, HR and fraction of inspired oxygen (FiO2), except for FiO2 in minute 11, with higher FiO2 in the adverse outcome group.ConclusionPreterm neonates with adverse outcome had beside lower gestational age also a lower crSO2 during immediate fetal-to-neonatal transition when compared to preterm neonates with age appropriate outcome. Lower gestational age in the adverse outcome group would suggest beside lower crSO2 also lower SpO2 and HR in this group, which were however similar in both groups.

Early vasopressin infusion improves oxygenation in infants with congenital diaphragmatic hernia.

Congenital Diaphragmatic Hernia (CDH) is a complex disease including a diaphragmatic defect, lung hypoplasia, and pulmonary hypertension. Despite its increasing use in neonates, the literature on the use of vasopressin in neonates is limited. The aim of this work is to analyze the changes in clinical and hemodynamic variables in a cohort of CDH infants treated with vasopressin. Among CDH infants managed at the Neonatal Intensive Care Unit (NICU) of our hospital from May 2014 to January 2019, all infants who were treated with vasopressin, because of systemic hypotension and pulmonary hypertension, were enrolled in this retrospective study. The primary outcome was the change in oxygenation index (OI) after the start of the infusion of vasopressin. The secondary outcomes were the changes in cerebral andsplanchnic fractional tissue oxygen extraction (FTOEc and FTOEs) at near-infrared spectroscopy, to understand the balance between oxygen supply and tissue oxygen consumption after the start of vasopressin infusion. We also reported as secondary outcomes the changes in ratio of arterial oxygen partial pressure (PaO2) to fraction of inspired oxygen (FiO2), heart rate, mean arterial pressure, serum pH, and serum sodium. We included 27 patients with isolated CDH who received vasopressin administration. OI dramatically dropped when vasopressin infusion started, with a significant reduction according to ANOVA for repeated measures (p = 0.003). A global significant improvement in FTOEc and FTOEs was detected (p = 0.009 and p = 0.004, respectively) as a significant reduction in heart rate (p = 0.019). A global significant improvement in PaO2/FiO2 ratio was observed (p < 0.001) and also at all time points: at 6 h since infusion (p = 0.015), 12 h (p = 0.009), and 24 h (p = 0.006), respectively. A significant reduction in sodium levels was observed as expected side effect (p = 0.012). No significant changes were observed in the remaining outcomes. Our data suggest that starting early vasopressin infusion in CDH infants with pulmonary hypertension could improve oxygenation index and near-infrared spectroscopy after 12 and 24 h of infusion. These pilot data represent a background for planning future larger randomized trials to evaluate the efficacy and safety of vasopressin for the CDH population.

Analysis of Fractional Cerebral Oxygen Extraction in Preterm Infants during the Kangaroo Care

Introduction: We aimed to investigate the cerebral fractional tissue oxygen extraction (FtOE) during kangaroo care (KC) in premature infants and compare cardiorespiratory stability and hypoxic or bradycardic events between KC and incubator care. Methods: A single-center prospective observational study was carried out at the NICU of a level 3 perinatal center. Preterm infants <32 weeks gestational age were subjected to KC. Patients were subjected to continuous monitoring of regional cerebral oxygen saturation (rScO₂), peripheral oxygen saturation (SpO₂), and heart rate (HR) during KC, before KC (pre-KC), and after KC (post-KC). The monitoring data were stored and exported to MATLAB for synchronization and signal analysis including the calculation of the FtOE and events analysis (i.e., desaturations and bradycardias counts and anormal values). Furthermore, the event counts and the mean SpO₂, HR, rScO₂, and FtOE were compared between studied periods employing the Wilcoxon rank-sum test and the Friedman test, respectively. Results: A total of forty-three KC sessions with their corresponding pre-KC and post-KC segments were analyzed. The distributions of the SpO₂, HR, rScO₂, and FtOE showed different patterns according to the respiratory support, but not differences between the studied periods were detected. Accordingly, no significant differences in monitoring events were evidenced. However, cerebral metabolic demand (FtOE) was significantly lower during KC compared with post-KC (p = 0.019). Conclusion: Premature infants remain clinically stable during KC. Moreover, cerebral oxygenation is significantly higher and cerebral tissular oxygen extraction is significantly lower during KC compared with incubator care in post-KC. No differences in HR and SpO₂ were shown. This novel data analysis methodology could be expanded to other clinical situations.

A pilot study: Comparing a novel noninvasive measure of cerebrovascular stability index with an invasive measure of cerebral autoregulation in neonates with congenital heart disease.

Infants with congenital heart disease (CHD) may have impaired cerebral autoregulation (CA) associated with cerebral fractional tissue oxygen extraction (FTOE). We conducted a pilot study in nine CHD neonates to validate a noninvasive CA measure, cerebrovascular stability index (CSI), by eliciting responses to postural tilts. We compared CSI to an invasive measure of CA and to FTOE collected during tilts (FTOESpot). FTOESpot correlated with CSI, as did the change in FTOE during tilts, but CSI's correlation with impaired CA did not reach significance. Larger trials are indicated to validate CSI, allowing for noninvasive CA measurements and measurements in outpatient settings.

Cerebral oxygenation during the period of transition to extrauterine life after natural versus cesarean birth

Objective. We aim to evaluate the implications of cesarean delivery compared to natural birth by analyzing newborns’ systemic and cerebral oxygenation levels during the first 10 minutes of life. Design. This paper presents a 4-year prospective cohort study. Setting. Polizu Maternity, "Alessandrescu-Rusescu" National Institute for Mother and Child's Protection, Bucharest, Romania. Patients. Randomly selected pregnant women and their fetuses. Interventions. During the 10 min following umbilical cord clamping, regional cerebral oxygen saturation (rcSO2) was measured using the INVOS 5100 device and peripheral oxygen saturation (SpO2) was determined using the Masimo SET pulse oximeter in neonates from cesarean and natural deliveries. Main outcome measures. The cerebral fractional tissue oxygen extraction (cFTOE) in the first 10 minutes of life was calculated based on these values. Results. Newborns delivered vaginally showed higher rcSO2 levels at 1 minute of life than those born via C-section (40.5 ± 16.5% vs 33.7 ± 14.8%, AUC = 0.625; IC 95%: 0.506 - 0.743; p = 0.043). Neonatal cFTOE at 1 minute of life was significantly higher in caesarean-delivered newborns versus naturally born neonates (0.40 ± 0.25 vs 0.50 ± 0.19, p = 0.03; AUC = 0.638; IC 95%: 0.517-0.758; p = 0.023). Conclusions. Prelabor cesarean delivery seemingly plays a significant role in the process of fetal and neonatal cerebral oxygenation immediately postnatally, which is highlighted by lower rcSO2 and higher cFTOE values. Cerebral oxygen saturation monitoring in the delivery room allows the optimization of oxygen therapy in order to prevent the consequences of hypoxia or hyperoxia.

Impact of Cerebral Oxygen Saturation Monitoring on Short-term Neurodevelopmental Outcomes in Neonates with Encephalopathy - A Prospective Cohort Study.

Near-infrared spectroscopy (NIRS) has been used for monitoring cerebral oxygen saturation (rSO2) in neonates. There is a lack of data from low-middle income countries (LMIC) setting of cerebral rSO2 in neonates with encephalopathy of diverse etiologies. This study aimed to monitor cerebral rSO2 using NIRS in encephalopathic neonates to maintain the rSO2 between 55 to 85 % in the first 72 hours of admission to improve short-term neurodevelopmental outcomes (NDO). This prospective cohort study enrolled encephalopathic neonates with hypoxic- ischemic encephalopathy (HIE) and non-HIE etiologies into 8 clinical categories. The cerebral rSO2 was monitored and targeted to be between 55 to 85 %, with predefined actions and management alterations over 72 hours. The neurodevelopmental assessment was conducted at 3, 6, and 9-12 months corrected age. Moreover, the motor and mental developmental quotients (MoDQ) (MeDQ) were recorded and compared to historical control. A total of 120 neonates were enrolled and assessed for NDO. The MoDQ (mean ± SD) was 92.55 ± 14.85, 93.80 ± 13.20, 91.02 ± 12.69 and MeDQ (mean ± SD) was 91.80 ± 12.98, 91.80 ± 13.69, 88.41 ± 11.60 at 3, 6 and 9-12 months. The MoDQ and MeDQ scores of the historic cohort at 12 months were 86.35 ± 20.34 and 86.58 ± 18.27. The mean difference [MD (95 %CI)] for MoDQ was - 4.670 (- 8.48 to - 0.85) (p=0.0165) and for MeDQ was - 1.83 (- 5.26 to 1.6) (p=0.29). There was a negative correlation between the composite developmental quotient (CoDQ) with mean rSO2 and a positive correlation with cerebral fractional tissue oxygen extraction (CFTOE). Neonates with HIE and neonatal encephalopathy (NE) (n=37/120) had the lowest motor and mental DQ on neurodevelopmental assessment. Clinical categories, neonatal meningitis (NM), and intraventricular hemorrhage (IVH) improved in DQ scores over the study period. Monitoring and maintaining cerebral rSO2 between 55-85 % through appropriate management changes improved neurodevelopmental scores at the 12-month follow-up in neonates with encephalopathy caused by varied etiologies.

Evolution of early cerebral NIRS in hypoxic ischaemic encephalopathy.

AimTo describe early cerebral oxygenation (cSO2) and fractional tissue oxygen extraction (FTOE) values and their evolution over the first days of life in infants with all grades of hypoxic‐ischaemic encephalopathy (HIE) and to determine whether cSO2 and FTOE measured early (6 and 12 h) can predict short‐term outcome.MethodsProspective, observational study of cerebral near‐infrared spectroscopy (NIRS) in infants >36 weeks' gestation with HIE. Ten one‐hour epochs of cSO2 and FTOE were extracted for each infant over the first 84 h. Infants with moderate and severe HIE received therapeutic hypothermia (TH). Abnormal outcome was defined as abnormal magnetic resonance imaging (MRI) and/or death.ResultsFifty‐eight infants were included (28 mild, 24 moderate, 6 severe). Median gestational age was 39.9 weeks (IQR 38.1–40.7) and birthweight was 3.35 kgs (IQR 2.97–3.71). cSO2 increased and FTOE decreased over the first 24 h in all grades of HIE. Compared to the moderate group, infants with mild HIE had significantly higher cSO2 at 6 h (p = 0.003), 9 h (p = 0.009) and 12 h (p = 0.032) and lower FTOE at 6 h (p = 0.016) and 9 h (0.029). cSO2 and FTOE at 6 and 12 h did not predict abnormal outcome.ConclusionInfants with mild HIE have higher cSO2 and lower FTOE than those with moderate or severe HIE in the first 12 h of life. cSO2 increased in all grades of HIE over the first 24 h regardless of TH status.

Fetal Hemoglobin and Cerebral Tissue Oxygenation during Immediate Postnatal Transition

Introduction: Concentration of fetal hemoglobin (HbFc) in human neonates determines oxygen-carrying capacity of blood and the position of oxyhemoglobin dissociation curve. Near-infrared spectroscopy enables the measurement of regional cerebral tissue oxygen saturation (rScO2) and in combination with measurements of pulsatile arterial oxygen saturation (SpO2), the calculation of cerebral fractional tissue oxygen extraction (cFTOE). Methods: We aimed to investigate the impact of HbFc on rScO2, cFTOE, and SpO2 in preterm and term neonates during the first 15 min after birth. Blood analyses provided total blood hemoglobin (Hb) and HbFc measurements. Correlations between HbFc, Hb and rScO2, cFTOE, and SpO2 in each minute were analyzed. Results: Ninety term and 19 preterm neonates without medical support were included. HbFc was significantly higher in preterm neonates, whereas there were no significant differences in Hb between the groups. In preterm neonates, we found positive correlations of both HbFc and Hb with rScO2 and negative correlations of HbFc and Hb with cFTOE in the first minutes after birth. In contrast, there were no significant correlations between the same parameters in term neonates. Correlations between HbFc or Hb and SpO2 were either insignificant, negligible, or very low in both groups. Discussion/Conclusion: In preterm neonates, higher HbFc was associated with higher rScO2 and lower cFTOE in the first minutes after birth. This phenomenon could not be confirmed in term neonates and might reflect immature autoregulation of oxygen delivery to the brain or lower oxygen consumption in preterm neonates in the first minutes of immediate postnatal transition.

Hierarchical improvement of regional tissue oxygenation after packed red blood cell transfusion.

BackgroundIt is well established that counter-regulation to hypoxia follows a hierarchical pattern, with brain-sparing in preference to peripheral tissues. In contrast, it is unknown if the same hierarchical sequence applies to recovery from hypoxia after correction of anemia with packed red blood cell transfusion (PRBCT).ObjectiveTo understand the chronology of cerebral and splanchnic tissue oxygenation resulting after correction of anemia by PRBCT in preterm infants using near-infrared spectroscopy (NIRS).DesignProspective cohort study.SettingNeonatal intensive care.Patients includedHaemodynamically stable infants: <32 weeks gestation, <37weeks postmenstrual age, <1500 grams birth weight; and ≥120 mL/kg/day feeds tolerated.InterventionPRBCT at 15 mL/Kg over 4 hours.Main outcome measuresTransfusion-associated changes were determined by comparing the 4-hour mean pre-transfusion cerebral and splanchnic fractional tissue oxygen extraction (FTOEc0; FTOEs0) with hourly means during (FTOEc1-4; FTOEs1-4) and for 24 hours after PRBCT completion (FTOEc5-28; FTOEs5-28).ResultsOf 30 enrolled infants, 14[46.7%] male; median[IQR] birth weight, 923[655–1064]g; gestation, 26.4[25.5–28.1]weeks; enrolment weight, 1549[1113–1882]g; and postmenstrual age, 33.6[32.4–35]weeks, 1 infant was excluded because of corrupted NIRS data. FTOEc significantly decreased during and for 24 hours after PRBCT (p < 0.001), indicating prompt improvement in cerebral oxygenation. In contrast, FTOEs showed no significant changes during and after PRBCT (p>0.05), indicating failure of improvement in splanchnic oxygenation.ConclusionImprovement in regional oxygenation after PRBCT follows the same hierarchical pattern with a prompt improvement of cerebral but not splanchnic tissue oxygenation. We hypothesise that this hierarchical recovery may indicate continued splanchnic hypoxia in the immediate post-transfusion period and vulnerability to transfusion-associated necrotizing enterocolitis (TANEC). Our study provides a possible mechanistic underpinning for TANEC and warrants future randomised controlled studies to stratify its prevention.

Low Dosing Norepinephrine Effects on Cerebral Oxygenation and Perfusion During Pediatric Shock.

BackgroundCerebral hypoperfusion and impaired oxygen delivery during pediatric critical illness may result in acute neurologic injury with subsequent long-term effects on neurodevelopmental outcome. Yet, the impact of norepinephrine on cerebral hemodynamics is unknown in children with shock. We aimed to describe the norepinephrine effects on cerebral perfusion and oxygenation during pediatric shock.Patients and MethodsWe conducted an observational multicentre prospective study in 3 French pediatric intensive care units. Children <18 years of age excluding traumatic brain injury were included in the study if they need norepinephrine for shock. Systemic and cerebral hemodynamics were compared between the time of initiation of norepinephrine (T0), and the steady-state (Tss). Cardiac output (CO) was measured using ultrasound. Cerebral perfusion was assessed on middle cerebral arteries (MCA) using transcranial doppler ultrasound. Cerebral tissue oxygen saturation (rScO2) was recorded using near infrared spectroscopy, and we calculated cerebral fractional tissue oxygen extraction (cFTOE = SpO2-rScO2/SpO2).Main ResultsFourteen children (median [IQR] age of 3.5[1; 13.5] years) were included. Norepinephrine at 0.2[0.1; 0.32] μg/kg/min significantly increased mean arterial blood pressure (61[56; 73] mmHg at Tss vs. 49[42;54] mmHg at T0, p=10−3) without change of CO. MCA velocities, pulsatility index, rScO2, and cFTOE did not significantly change between T0 and Tss. Some individuals observed variations in estimated CBF, which slightly improved in 7 patients, remained unchanged in 5, and was impaired in 2. No patient experienced significant variations of rScO2.ConclusionsLow-dosing norepinephrine, despite a homogeneous and significant increase in arterial blood pressure, had little effects on cerebral perfusion and oxygenation during pediatric shock. This reinforces the need for personalized tailored therapies in this population.Trial RegistrationClinicaltrials.gov, NCT 03731104. Registered 6 November, 2018. https://clinicaltrials.gov/ct2/show/NCT03731104.