Monitoring Cerebral Oxygenation in Neonates: An Update

Blood pressure and cerebral oxygenation with physiologically-based cord clamping: sub-study of the BabyDUCC trial

BACKGROUND

Cord-clamping strategies may modify blood pressure (BP) and cerebral tissue oxygen saturation (rStO2) immediately after birth.

METHODS

We conducted a sub-study nested within the Baby-Directed Umbilical Cord-Clamping trial. Infants ≥32+0 weeks' gestation assessed as requiring resuscitation were randomly allocated to either physiologically-based cord clamping (PBCC), where resuscitation commenced prior to umbilical cord clamping, or standard care where cord clamping occurred early (ECC). In this single-site sub-study, we obtained additional measurements of pre-ductal BP and rStO2. In a separate observational arm, non-randomised vigorous infants received 2 min of deferred cord clamping (DCC) and contributed data for reference percentiles.

RESULTS

Among 161 included infants, n = 55 were randomly allocated to PBCC (n = 30) or ECC (n = 25). The mean (SD) BP at 3-4 min after birth (primary outcome) in the PBCC group was 64 (10) mmHg compared to 62 (10) mmHg in the ECC group, mean difference 2 mmHg (95% confidence interval -3-8 mmHg, p = 0.42). BP and rStO2 were similar across both randomised arms and the observational arm (n = 106).

CONCLUSION

We found no difference in BP or rStO2 with the different cord clamping strategies. We report reference ranges for BP and rStO2 for late-preterm and full-term infants receiving DCC.

IMPACT

Among late-preterm and full-term infants receiving varying levels of resuscitation, blood pressure (BP, at 3-4 minutes and 6 min) and cerebral tissue oxygen saturation (rStO2) are not influenced by timing of cord clamping in relation to establishment of ventilation. Infants in this study did not require advanced resuscitation, where cord clamping strategies may yet influence BP and rStO2. The reference ranges for BP and rStO2 represent the first, to our knowledge, for vigorous late-preterm and full-term infants receiving deferred cord clamping. rStO2 > 90% (~90th percentile) may be used to define cerebral hyperoxia, for instance when studying oxygen supplementation after birth.

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.

Cerebrovascular responses to a 90° tilt in healthy neonates

BACKGROUND

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.

METHODS

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 neonates were 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.

RESULTS

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.

CONCLUSION

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.

IMPACT

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.

Predictive Utility of Near-Infrared Spectroscopy for the Outcomes of Hypoxic-Ischemic Encephalopathy: A Systematic Review and Meta-Analysis

This systematic review and meta-analysis aimed to assess the utility of near-infrared spectroscopy (NIRS) in predicting the perinatal outcomes of neonates with hypoxic-ischemic encephalopathy (HIE). We conducted a literature search on Medline via PubMed, Web of Science, Scopus, and CENTRAL Library. We included studies that utilized early NIRS monitoring to study the accuracy of NIRS in predicting the perinatal outcomes of neonates with hypoxic-ischemic encephalopathy. Nine studies that met our eligibility criteria were included. These studies were published between 2012 and 2023. In this meta-analysis, no significant differences in regional cerebral oxygen saturation (cSpO2) were found between normal and abnormal groups at 12 hours (MD = 0.21, 95% CI: -6.39 to 6.82, P = 0.95) and 24 hours (MD = -1.96, 95% CI: -6.95 to 3.03, P = 0.44). However, at 48 hours, cSpO2 was significantly lower in the normal group (MD = -4.9, 95% CI: -5.91 to -3.89, P < 0.00001). At 72 hours, our analysis revealed a significant difference with lower cSpO2 in the normal group (MD = -3.0, 95% CI: -5.5 to -0.5, P = 0.02). Regarding cerebral fractional tissue oxygen extraction (FTOE), no significant differences were observed at 12 hours (MD = 0.03, 95% CI: -0.02 to 0.09, P = 0.24). After 24 hours, the normal group exhibited lower FTOE (MD = -0.03, 95% CI: -0.04 to -0.01, P < 0.001), while after 48 hours, the normal group had higher FTOE (MD = 0.07, 95% CI: 0.04 to 0.10, P < 0.0001). Early cerebral NIRS monitoring is beneficial in predicting the outcomes of HIE in term neonates. Our analysis showed that several NIRS parameters, such as regional cSpO2 and cerebral FTOE, are significantly associated with adverse outcomes in the first 72 hours of birth.

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.

Impact of cardiopulmonary bypass on cerebrovascular autoregulation assessed by ultrafast ultrasound imaging

Newborns with congenital heart disease undergoing cardiac surgery are at risk of neurodevelopmental impairment with limited understanding of the impact of intra-operative cardiopulmonary bypass (CPB), deep hypothermia and selective cerebral perfusion on the brain. We hypothesized that a novel ultrasound technique, ultrafast power Doppler (UPD), can assess variations of cerebral blood volume (CBV) in neonates undergoing cardiac surgery requiring CPB. UPD was performed before, during and after surgery in newborns with hypoplastic left heart syndrome undergoing a Norwood operation. We found that global CBV was not significantly different between patients and controls (P = 0.98) and between pre- and post-surgery (P = 0.62). UPD was able to monitor changes in CBV throughout surgery, revealing regional differences in CBV during hypothermia during which CBV correlated with CPB flow rate (R²  = 0.52, P = 0.021). Brain injury on post-operative magnetic resonance imaging was observed in patients with higher maximum variation in CBV. Our findings suggest that UPD can quantify global and regional brain perfusion variation during neonatal cardiac surgery with this first intra-operative application demonstrating an association between CBV and CPB flow rate, suggesting loss of autoregulation. Therefore, the measurement of CBV by UPD could enable optimization of cerebral perfusion during cardiac surgery in neonates. KEY POINTS: The impact of cardiopulmonary bypass (CPB) on the neonatal brain undergoing cardiac surgery is poorly understood. Ultrafast power Doppler (UPD) quantifies cerebral blood volume (CBV), a surrogate of brain perfusion. CBV varies throughout CPB surgery and is associated with variation of the bypass pump flow rate during deep hypothermia. Association between CBV and bypass pump flow rate suggests loss of cerebrovascular autoregulatory processes. Quantitative monitoring of cerebral perfusion by UPD could provide a direct parameter to optimize CPB flow rate.

Abdominal Near Infrared Spectroscopy can be reliably used to measure splanchnic oxygenation changes in preterm infants

OBJECTIVE

Near-infrared spectroscopy (NIRS) allows assessment of regional tissue oxygen delivery and extraction. There are doubts regarding reliability of gut NIRS measurements. This study assesses reliability of NIRS for monitoring gut oxygenation.

STUDY DESIGN

Splanchnic tissue haemoglobin index (sTHI), tissue oxygenation index (sTOI) and fractional tissue oxygen extraction (sFTOE) changes during blood transfusion were measured using NIRS and compared to stable control infants. Infants were grouped into 3 chronological age groups: 1-7, 8-28 and ≥29 days of life.

RESULTS

sTHI, sTOI significantly increased, and sFTOE reduced following blood transfusion in all age group infants (n = 59), with no changes seen in control infants (n = 12). Baseline characteristics including gestational age and feed volumes did not differ between groups.

CONCLUSION

Gut perfusion measured by NIRS improved in infants who received blood transfusion, a change not seen in the control group, thus suggesting NIRS is a reliable method to measure splanchnic tissue oxygenation.

The Quantitative Associations Between Near Infrared Spectroscopic Cerebrovascular Metrics and Cerebral Blood Flow: A Scoping Review of the Human and Animal Literature

Cerebral blood flow (CBF) is an important physiologic parameter that is vital for proper cerebral function and recovery. Current widely accepted methods of measuring CBF are cumbersome, invasive, or have poor spatial or temporal resolution. Near infrared spectroscopy (NIRS) based measures of cerebrovascular physiology may provide a means of non-invasively, topographically, and continuously measuring CBF. We performed a systematically conducted scoping review of the available literature examining the quantitative relationship between NIRS-based cerebrovascular metrics and CBF. We found that continuous-wave NIRS (CW-NIRS) was the most examined modality with dynamic contrast enhanced NIRS (DCE-NIRS) being the next most common. Fewer studies assessed diffuse correlation spectroscopy (DCS) and frequency resolved NIRS (FR-NIRS). We did not find studies examining the relationship between time-resolved NIRS (TR-NIRS) based metrics and CBF. Studies were most frequently conducted in humans and animal studies mostly utilized large animal models. The identified studies almost exclusively used a Pearson correlation analysis. Much of the literature supported a positive linear relationship between changes in CW-NIRS based metrics, particularly regional cerebral oxygen saturation (rSO2), and changes in CBF. Linear relationships were also identified between other NIRS based modalities and CBF, however, further validation is needed.

Is low cerebral near infrared spectroscopy oximetry associated with neurodevelopment of preterm infants without brain injury?

OBJECTIVES

To evaluate the association between low regional cerebral oxygen saturation (rScO2) and neurodevelopment in preterm infants classified as no brain injury (NBI).

METHODS

We retrospectively reviewed data of rScO2 monitoring during the first 3 days of life of infants with a gestational age (GA)<28 weeks or birth weight (BW)<1,000 g, with and without brain injury (BI). BI was defined as intraventricular haemorrhage, cystic periventricular leukomalacia or cerebellar haemorrhage. Univariate and multivariate analyses were used to study the association of rScO2<55% for more than 10 h in the first 3 days of life (NIRS<55%^>10H) and the 24 months neurodevelopment.

RESULTS

Of the 185 patients who met the inclusion criteria, 31% were classified as BI infants and 69% NBI. BI compared to NBI infants had a significantly lower GA and a higher incidence of complications of prematurity. Mean rScO2 in the first 72 h of life was significantly lower in BI than NBI. NIRS<55%^>10H in NBI patients was negatively associated with neurodevelopmental scores both at the univariate and multivariate analysis (p<0.05). NBI infants with NIRS<55%^>10H were found to have lower systemic oxygenation than their counterparts with rScO2<55% for less than 10 h.

CONCLUSIONS

NIRS<55%^>10H in NBI small preterm infants was found to be an independent predictor of neurodevelopment at 24 months and it was associated with low systemic saturation values.

Association Analysis of the Cerebral Fractional Tissue Oxygen Extraction (cFTOE) and the Cerebral Oxygen Saturation (crSaO2) with Perinatal Factors in Preterm Neonates: A Single Centre Study

(1) Background: Near-infrared spectroscopy (NIRS) is a non-invasive, easily performed method of monitoring brain oxygenation. The regional cerebral oxygen saturation (crSaO2) and the cerebral fractional tissue oxygen extraction (cFTOE) evaluated by NIRS provide more accurate information on brain oxygenation than the blood oxygen saturation. We investigated the effect of perinatal factors on cerebral oxygenation of preterm newborns. (2) Methods: We conducted a longitudinal study with 48 preterm newborns <34 weeks of gestation who underwent NIRS registration during the first 72 h of life. crSaO2 was measured and cFTOE was calculated foreach patient. (3) Results: One-way ANOVA showed no significant main effect of IVH severity on crSaO2 and cFTOE (p > 0.05); there was a tendency toward statistical significance concerning the difference between the means of crSaO2 (p = 0.083) and cFTOE (p = 0.098). Patients with intraventricular haemorrhage (IVH) had a lower mean of crSaO2 and a higher mean of cFTOE (59.67 ± 10.37% vs. 64.92 ± 10.16% for crSaO2; 0.37 ± 0.11 vs. 0.32 ± 0.11 for cFTOE) compared to those with no IVH. Significantly lower values of crSaO2 and higher values of cFTOE were found in neonates receiving inotropic treatment (p < 0.0001). Episodes of apnoea also proved to influence the cerebral oxygen saturation of the study group (p = 0.0026). No significant association between the maternal hypertension treatment and the cerebral oxygenation of preterms was found. (4) Conclusions: This study showed a decreased cerebral oxygen saturation of preterms with IVH, inotrope support and apnoea episodes.

Assessing cerebral blood flow, oxygenation and cytochrome c oxidase stability in preterm infants during the first 3 days after birth

A major concern with preterm birth is the risk of neurodevelopmental disability. Poor cerebral circulation leading to periods of hypoxia is believed to play a significant role in the etiology of preterm brain injury, with the first three days of life considered the period when the brain is most vulnerable. This study focused on monitoring cerebral perfusion and metabolism during the first 72 h after birth in preterm infants weighing less than 1500 g. Brain monitoring was performed by combining hyperspectral near-infrared spectroscopy to assess oxygen saturation and the oxidation state of cytochrome c oxidase (oxCCO), with diffuse correlation spectroscopy to monitor cerebral blood flow (CBF). In seven of eight patients, oxCCO remained independent of CBF, indicating adequate oxygen delivery despite any fluctuations in cerebral hemodynamics. In the remaining infant, a significant correlation between CBF and oxCCO was found during the monitoring periods on days 1 and 3. This infant also had the lowest baseline CBF, suggesting the impact of CBF instabilities on metabolism depends on the level of blood supply to the brain. In summary, this study demonstrated for the first time how continuous perfusion and metabolic monitoring can be achieved, opening the possibility to investigate if CBF/oxCCO monitoring could help identify preterm infants at risk of brain injury.

Association of regional cerebral oxygen saturation and postoperative pulmonary complications in pediatric patients undergoing one-lung ventilation: A propensity score matched analysis of a prospective cohort study

BACKGROUND

Previous studies of the relationship of regional cerebral oxygen saturation (rScO2) and postoperative pulmonary complications (PPCs) in pediatric patients are not well established, and further investigation is warranted. The aim of this prospective study was to determine whether a decrease in intraoperative rScO2 is associated with PPCs in children undergoing thoracoscopic surgery requiring one-lung ventilation (OLV).

METHODS

One hundred and six children of ages 3 months to 8 years who received one-lung ventilation were enrolled in the study. Upon entering the operating room, regional cerebral oxygen saturation was continuously monitored bilaterally by near-infrared spectroscopy. Patients were divided into low rScO2 (L-rScO2) or high rScO2 (H- rScO2) groups according to whether the lowest intraoperative rScO2 value was 15% lower than the baseline value. Outcome is defined as PPCs occurring within 7 days after surgery.

RESULTS

After propensity score matching, 23 pediatric patients with decreased rScO2 and 46 pediatric patients without a decrease in rScO2 were included in this study. According to logistic regression analysis, patients in the H- rScO2 group were less likely to have PPCs than those in the L-rScO2 group (OR = 3.16; 95% CI = 1.05-9.5; P = 0.04). Moreover, intraoperative rScO2 reduction was associated with an increase in the severity of PPCs (OR = 3.90; 95% CI = 1.19-12.80; P = 0.025).

CONCLUSIONS

The decrease in regional cerebral oxygen saturation during surgery increases the likelihood of postoperative pulmonary complications.

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

BACKGROUND

Cerebral 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 METHODS

We 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 (T_ss). 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 RESULTS

Fourteen 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 T_ss 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 T_ss. 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.

CONCLUSIONS

Low-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 REGISTRATION

Clinicaltrials.gov, NCT03731104. Registered 6 November, 2018. https://clinicaltrials.gov/ct2/show/NCT03731104.

Cortical hemodynamic activity and pain perception during insertion of feeding tubes in preterm neonates: a randomized controlled cross-over trial

OBJECTIVE

The present study evaluated the pain perception in preterm neonates during insertion of orogastric (OG) vs. nasogastric (NG) tube by measuring the cerebral regional oxygen saturation (crSO2) and premature infant pain profile-revised (PIPP-R) score.

STUDY DESIGN

Randomized controlled cross-over trial.

RESULTS

Fifty infants of mean (SD) gestational age of 31.54(2) and 31.64(2.2) weeks, birth weight of 1362(354) and 1507(365) grams were randomized into OG/NG (n = 25) and NG/OG (n = 25) sequences. Mean post-menstrual age at assessment was 33(2.8) and 33(1.5) weeks, and the difference between two interventions was 1.08(0.5) and 1.12(0.5) days in OG-NG and NG-OG, respectively. Mean crSO2(%) during insertion was significantly lower with NG compared to OG route. Mean PIPP-R score, heart rate variability, time to normalize crSO2, and the duration of cry were also significantly higher with NG insertion.

CONCLUSIONS

Compared to OG, NG route of feeding tube insertion was associated with higher fluctuations in crSO2 and higher PIPP-R scores.

CLINICAL TRIAL REGISTRY OF INDIA (CTRI) REGISTRATION NO

CTRI/2020/03/023728.

A case of transfusion-associated necrotizing enterocolitis in neonates

A male infant, whose weight was 1 120 g at 28+2 weeks of gestational age, was admitted to Neonatal Intensive Care Unit of West China Second Hospital of Sichuan University at 20 min after preterm birth. Blood transfusion was performed for anemia (hemoglobin 81 g/L) on day 30 of hospitalization, and feeding was continued during the transfusion. Eight hours after blood transfusion, the patient's manifestations included abdominal distension and stiff to palpation, bowel sound weakening, currant jelly stool, poor responsiveness, and apnea. The clinical diagnosis was necrotizing enterocolitis. Abdominal X-ray showed that the abdominal bowel was significantly dilated and inflated. The patient was immediately treated with fasting, gastrointestinal decompression, enema, and anti-infection treatment. After 40 days in hospital, the patient recovered and was discharged.

Cerebral blood volume increment after resuscitation measured by near-infrared time-resolved spectroscopy can estimate degree of hypoxic-ischemic insult in newborn piglets

Neonatal hypoxic–ischemic encephalopathy is a notable cause of neonatal death and developmental disabilities. To achieve better outcomes, it is important in treatment strategy selection to categorize the degree of hypoxia ischemia and evaluate dose response. In an asphyxia piglet model with histopathological brain injuries that we previously developed, animals survived 5 days after insult and showed changes in cerebral blood volume (CBV) that reflected the severity of injuries. However, little is known about the relationship between changes in CBV during and after insult. In this study, an HI event was induced by varying the amount and timing of inspired oxygen in 20 anesthetized piglets. CBV was measured using near-infrared time-resolved spectroscopy before, during, and 6 h after insult. Change in CBV was calculated as the difference between the peak CBV value during insult and the value at the end of insult. The decrease in CBV during insult was found to correlate with the increase in CBV within 6 h after insult. Heart rate exhibited a similar tendency to CBV, but blood pressure did not. Because the decrement in CBV was larger in severe HI, the CBV increment immediately after insult is considered useful for assessing degree of HI insult.

Effectiveness of interventions on early neurodevelopment of preterm infants: a systematic review and meta-analysis

BACKGROUND

As preterm infants' neurodevelopment is shaped by NICU-related factors during their hospitalization, it is essential to evaluate which interventions are more beneficial for their neurodevelopment at this specific time. The objective of this systematic review and meta-analysis was to evaluate the effectiveness of interventions initiated during NICU hospitalization on preterm infants' early neurodevelopment during their hospitalization and up to two weeks corrected age (CA).

METHODS

This systematic review referred to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses [PRISMA] guidelines and was registered in PROSPERO (CRD42017047072). We searched CINAHL, MEDLINE, PubMed, EMBASE (OVID), Cochrane Systematic Reviews, CENTRAL, and Web of Science from 2002 to February 2020 and included randomized controlled/clinical trials conducted with preterm infants born between 24 and 366/7 weeks of gestation. All types of interventions instigated during NICU hospitalization were included. Two independent reviewers performed the study selection, data extraction, assessment of risks of bias and quality of evidence.

RESULTS

Findings of 12 studies involving 901 preterm infants were synthesized. We combined three studies in a meta-analysis showing that compared to standard care, the NIDCAP intervention is effective in improving preterm infants' neurobehavioral and neurological development at two weeks CA. We also combined two other studies in a meta-analysis indicating that parental participation did not significantly improve preterm infants' neurobehavioral development during NICU hospitalization. For all other interventions (i.e., developmental care, sensory stimulation, music and physical therapy), the synthesis of results shows that compared to standard care or other types of comparators, the effectiveness was either controversial or partially effective.

CONCLUSIONS

The overall quality of evidence was rated low to very low. Future studies are needed to identify interventions that are the most effective in promoting preterm infants' early neurodevelopment during NICU hospitalization or close to term age. Interventions should be appropriately designed to allow comparison with previous studies and a combination of different instruments could provide a more global assessment of preterm infants' neurodevelopment and thus allow for comparisons across studies.

TRIAL REGISTRATION

Prospero CRD42017047072 .

Accuracy of homogeneous models for photon diffusion in estimating neonatal cerebral hemodynamics by TD-NIRS

We assessed the accuracy of homogenous (semi-infinite, spherical) photon diffusion models in estimating absolute hemodynamic parameters of the neonatal brain in realistic scenarios (ischemia, hyperoxygenation, and hypoventilation) from 1.5 cm interfiber distance TD NIRS measurements. Time-point-spread-functions in 29- and 44-weeks postmenstrual age head meshes were simulated by the Monte Carlo method, convoluted with a real instrument response function, and then fitted with photon diffusion models. The results show good accuracy in retrieving brain oxygen saturation, and severe underestimation of total cerebral hemoglobin, suggesting the need for more complex models of analysis or of larger interfiber distances to precisely monitor all hemodynamic parameters.

Germinal Matrix-Intraventricular Hemorrhage: A Tale of Preterm Infants

Germinal matrix-intraventricular hemorrhage (GM-IVH) is a common intracranial complication in preterm infants, especially those born before 32 weeks of gestation and very-low-birth-weight infants. Hemorrhage originates in the fragile capillary network of the subependymal germinal matrix of the developing brain and may disrupt the ependymal lining and progress into the lateral cerebral ventricle. GM-IVH is associated with increased mortality and abnormal neurodevelopmental outcomes such as posthemorrhagic hydrocephalus, cerebral palsy, epilepsy, severe cognitive impairment, and visual and hearing impairment. Most affected neonates are asymptomatic, and thus, diagnosis is usually made using real-time transfontanellar ultrasound. The present review provides a synopsis of the pathogenesis, grading, incidence, risk factors, and diagnosis of GM-IVH in preterm neonates. We explore brief literature related to outcomes, management interventions, and pharmacological and nonpharmacological prevention strategies for GM-IVH and posthemorrhagic hydrocephalus.

Cerebral oxygenation monitoring of ex-preterm infants during the infant car seat challenge test

The American Academy of Pediatrics and until recently the Canadian Paediatric Society recommend preterm infants undergo an Infant Car Seat Challenge test prior to discharge to rule out systemic oxygen desaturation when placed at a 45-degree angle in a car seat. Near-infrared spectroscopy (NIRS) provides objective measurements of the impact of systemic oxygen (SO₂) desaturation, bradycardia, or both on cerebral regional oxygen saturation (rSO₂).

Objective

To characterize baseline cerebral rSO₂ during a car seat trial in preterm infants ready for discharge.

Design/Methods

A prospective observational study was performed in 20 infants (32 ± 5 weeks [mean] at a postmenstrual age 37 ± 6 weeks [mean]). Cerebral rSO₂ was continuously monitored by placing a NIRS transducer on head during Infant Car Seat Challenge (ICSC). Failure of an ICSC was defined as two SO₂ desaturation events below 85% for more than 20 seconds or one event below 80% for 10 seconds.

Results

The lowest SO₂ was 70% with a lowest NIRS recording of 68%. Three infants failed their ICSC, with the lowest rSO₂ in these three infants being 68%, above the lowest acceptable limit of 55%. Heart rate but not SO₂ appears to influence rSO₂ over the range of cerebral oxygenation seen.

Conclusions

Baseline cerebral rSO₂ during ICSC oscillates between 68 and 90%. There were no episodes of significant cerebral oxygen desaturation in studied infants regardless of whether they passed or failed the ICSC. We postulate that former preterm infants are capable through cerebral autoregulation, of maintaining adequate cerebral blood flow in the presence of either systemic oxygen desaturation or bradycardia when they are otherwise ready for discharge.

Cortical Oxygenation Changes during Gastric Tube Feeding in Moderate- and Late-Preterm Babies: A NIRS Study

Smell and taste of food can trigger physiological responses facilitating digestion and metabolism of nutrients. Controlled experimental studies in preterm babies have demonstrated that smell activates the orbitofrontal cortex (OFC) but none have investigated the effect of taste stimulation. Using cotside Near-Infrared Spectroscopy (NIRS), we measured changes in OFC cerebral oxygenation in response to gastric tube feeds five and 10 days after birth in 53 assessments of 35 moderate- to late-preterm babies enrolled in a randomized trial. Babies were randomly assigned to receive smell and taste of milk before gastric tube feeds (intervention group, n = 16) or no exposure (control group, n = 19). The majority of babies were born at 33 weeks of gestation (range 32–34) and 69% were boys. No differences in OFC cerebral oxygenation were observed between control and intervention groups. Gastric tube feeds induced activation of the OFC (p < 0.05), but sensory stimulation alone with smell and taste did not. Boys, but not girls, showed activation of the OFC following exposure to smell of milk (p = 0.01). The clinical impact of sensory stimulation prior to tube feeds on nutrition of preterm babies, as well as the impact of environmental inputs on cortical activation, remains to be determined.

Cerebral Blood Flow Monitoring in High-Risk Fetal and Neonatal Populations

Cerebrovascular pressure autoregulation promotes stable cerebral blood flow (CBF) across a range of arterial blood pressures. Cerebral autoregulation (CA) is a developmental process that reaches maturity around term gestation and can be monitored prenatally with both Doppler ultrasound and magnetic resonance imaging (MRI) techniques. Postnatally, there are key advantages and limitations to assessing CA with Doppler ultrasound, MRI, and near-infrared spectroscopy. Here we review these CBF monitoring techniques as well as their application to both fetal and neonatal populations at risk of perturbations in CBF. Specifically, we discuss CBF monitoring in fetuses with intrauterine growth restriction, anemia, congenital heart disease, neonates born preterm and those with hypoxic-ischemic encephalopathy. We conclude the review with insights into the future directions in this field with an emphasis on collaborative science and precision medicine approaches.

Cerebral Oxygenation and Activity During Surgical Repair of Neonates With Congenital Diaphragmatic Hernia: A Center Comparison Analysis

Background and aim: Neonatal brain monitoring is increasingly used due to reports of brain injury perioperatively. Little is known about the effect of sedatives (midazolam) and anesthetics (sevoflurane) on cerebral oxygenation (rScO₂) and cerebral activity. This study aims to determine these effects in the perioperative period. Methods: This is an observational, prospective study in two tertiary pediatric surgical centers. All neonates with a congenital diaphragmatic hernia received perioperative cerebral oxygenation and activity measurements. Patients were stratified based on intraoperatively administrated medication: the sevoflurane group (continuous sevoflurane, bolus fentanyl, bolus rocuronium) and the midazolam group (continuous midazolam, continuous fentanyl, and continuous vecuronium). Results: Intraoperatively, rScO₂ was higher in the sevoflurane compared to the midazolam group (84%, IQR 77-95 vs. 65%, IQR 59-76, p = < 0.001), fractional tissue oxygen extraction was lower (14%, IQR 5-21 vs. 31%, IQR 29-40, p = < 0.001), the duration of hypoxia was shorter (2%, IQR 0.4-9.6 vs. 38.6%, IQR 4.9-70, p = 0.023), and cerebral activity decreased more: slow delta: 2.16 vs. 4.35 μV ² (p = 0.0049), fast delta: 0.73 vs. 1.37 μV ² (p = < 0.001). In the first 30 min of the surgical procedure, a 3-fold increase in fast delta (10.48-31.22 μV ²) and a 5-fold increase in gamma (1.42-7.58 μV ²) were observed in the midazolam group. Conclusion: Sevoflurane-based anesthesia resulted in increased cerebral oxygenation and decreased cerebral activity, suggesting adequate anesthesia. Midazolam-based anesthesia in neonates with a more severe CDH led to alarmingly low rScO₂ values, below hypoxia threshold, and increased values of EEG power during the first 30 min of surgery. This might indicate conscious experience of pain. Integrating population-pharmacokinetic models and multimodal neuromonitoring are needed for personalized pharmacotherapy in these vulnerable patients. Trial Registration: https://www.trialregister.nl/trial/6972, identifier: NL6972.

Effectiveness of Gentle Human Touch for Pain Control During Examination for Retinopathy of Pre-maturity: A Randomized Controlled Trial

Background: Retinopathy of pre-maturity (ROP) is a disorder of the retinal blood vessels in pre-term infants with low birth weight. It is a leading cause of blindness in children. During ROP screening, the use of mydriatic drops and eyelid openers causes pain and discomfort. Pain management strategies include medications and behavioral interventions. The objectives of this study was to investigate the effects of Gentle Human Touch on pain in pre-term infants undergoing screening for ROP. Methods: In this randomized controlled trial, 82 infants in the neonatal intensive care unit at Children's Hospital of Nanjing Medical University who met the ROP screening criteria were randomly assigned to experimental and control groups using the random number table. The infants in the experimental group continuously received Gentle Human Touch during screening, while those in the control group were screened according to the routine procedure. All neonates were administered local eye anesthesia before the screening. The degree of pain was assessed using the Pre-mature Infant Pain Profile score. A double-channel near-infrared spectroscopy device was used to monitor regional cerebral oxygen saturation (rScO2), while oxygen saturation (SaO2) and heart rate were measured using pulse oximetry. The Pre-mature Infant Pain Profile score was the primary outcome, while heart rate, SaO2, and rScO2 were the secondary outcomes. Results: The gestational age, corrected gestational age, birth weight, and Apgar score at examination and the basal heart rate, SaO2, and rScO2 showed no significant intergroup differences (P > 0.05 for all). Both groups demonstrated significant decreases in SaO2 and rScO2 in response to the examination (P < 0.05 for all). During the examination, the Pre-mature Infant Pain Profile score (14.82 ± 3.22 vs. 9.29 ± 2.89, respectively; P < 0.05) was significantly higher in the control group than in the experimental group, while rScO2 (57.61 ± 3.51 vs. 54.76 ± 4.54%, respectively; P < 0.05) and SaO2 (91.89 ± 6.43 vs. 85.68 ± 8.31%; P < 0.05) were significantly higher in the experimental group than in the control group. There was no significant difference in heart rate changes between the two groups before and after the examination (182.60 ± 3.50 vs. 170.80 ± 3.50 time/min; P > 0.05). Conclusions: The findings of this study suggest that Gentle Human Touch can effectively alleviate pain during ROP screening in pre-mature infants. Clinical Trial Registration: ISRCTN10976481, Registered 06 March 2020, Retrospectively registered.

Excess cerebral oxygen delivery follows return of spontaneous circulation in near-term asphyxiated lambs

Hypoxic-ischaemia renders the neonatal brain susceptible to early secondary injury from oxidative stress and impaired autoregulation. We aimed to describe cerebral oxygen kinetics and haemodynamics immediately following return of spontaneous circulation (ROSC) and evaluate non-invasive parameters to facilitate bedside monitoring. Near-term sheep fetuses [139 ± 2 (SD) days gestation, n = 16] were instrumented to measure carotid artery (CA) flow, pressure, right brachial arterial and jugular venous saturation (SaO2 and SvO2, respectively). Cerebral oxygenation (crSO2) was measured using near-infrared spectroscopy (NIRS). Following induction of severe asphyxia, lambs received cardiopulmonary resuscitation using 100% oxygen until ROSC, with oxygen subsequently weaned according to saturation nomograms as per current guidelines. We found that oxygen consumption did not rise following ROSC, but oxygen delivery was markedly elevated until 15 min after ROSC. CrSO2 and heart rate each correlated with oxygen delivery. SaO2 remained > 90% and was less useful for identifying trends in oxygen delivery. CrSO2 correlated inversely with cerebral fractional oxygen extraction. In conclusion, ROSC from perinatal asphyxia is characterised by excess oxygen delivery that is driven by rapid increases in cerebrovascular pressure, flow, and oxygen saturation, and may be monitored non-invasively. Further work to describe and limit injury mediated by oxygen toxicity following ROSC is warranted.

Cerebral Near Infrared Spectroscopy Monitoring in Term Infants With Hypoxic Ischemic Encephalopathy-A Systematic Review

Background: Neonatal hypoxic ischemic encephalopathy (HIE) remains a significant cause of mortality and morbidity worldwide. Cerebral near infrared spectroscopy (NIRS) can provide cot side continuous information about changes in brain hemodynamics, oxygenation and metabolism in real time.

Objective: To perform a systematic review of cerebral NIRS monitoring in term and near-term infants with HIE.

Search Methods: A systematic search was performed in Ovid EMBASE and Medline database from inception to November 2019. The search combined three broad categories: measurement (NIRS monitoring), disease condition [hypoxic ischemic encephalopathy (HIE)] and subject category (newborn infants) using a stepwise approach as per PRISMA guidance.

Selection Criteria: Only human studies published in English were included.

Data Collection and Analysis: Two authors independently selected, assessed the quality, and extracted data from the studies for this review.

Results: Forty-seven studies on term and near-term infants following HIE were identified. Most studies measured multi-distance NIRS based cerebral tissue saturation using monitors that are referred to as cerebral oximeters. Thirty-nine studies were published since 2010; eight studies were published before this. Fifteen studies reviewed the neurodevelopmental outcome in relation to NIRS findings. No randomized study was identified.

Conclusion: Commercial NIRS cerebral oximeters can provide important information regarding changes in cerebral oxygenation and hemodynamics following HIE and can be particularly helpful when used in combination with other neuromonitoring tools. Optical measurements of brain metabolism using broadband NIRS and cerebral blood flow using diffuse correlation spectroscopy add additional pathophysiological information. Further randomized clinical trials and large observational studies are necessary with proper study design to assess the utility of NIRS in predicting neurodevelopmental outcome and guiding therapeutic interventions.

Renal Tissue Oxygenation Monitoring-An Opportunity to Improve Kidney Outcomes in the Vulnerable Neonatal Population

Adequate oxygenation of the kidney is of critical importance in the neonate. Non-invasive monitoring of renal tissue oxygenation using near-infrared spectroscopy (NIRS) is a promising bedside strategy for early detection of circulatory impairment as well as recognition of specific renal injury. As a diagnostic tool, renal NIRS monitoring may allow for earlier interventions to prevent or reduce injury in various clinical scenarios in the neonatal intensive care unit. Multiple studies utilizing NIRS monitoring in preterm and term infants have provided renal tissue oxygenation values at different time points during neonatal hospitalization, and have correlated measures with ultrasound and Doppler flow data. With the establishment of normal values, studies have utilized renal tissue oxygenation monitoring in preterm neonates to predict a hemodynamically significant patent ductus arteriosus, to assess response to potentially nephrotoxic medications, to identify infants with sepsis, and to describe changes after red blood cell transfusions. Other neonatal populations being investigated with renal NIRS monitoring include growth restricted infants, those requiring delivery room resuscitation, infants with congenital heart disease, and neonates undergoing extracorporeal membrane oxygenation. Furthermore, as the recognition of acute kidney injury (AKI) and its associated morbidity and mortality in neonates has increased over the last decade, alternative methods are being investigated to diagnose AKI before changes in serum creatinine or urine output occur. Studies have utilized renal NIRS monitoring to diagnose AKI in specific populations, including neonates with hypoxic ischemic encephalopathy after birth asphyxia and in infants after cardiac bypass surgery. The use of renal tissue oxygenation monitoring to improve renal outcomes has yet to be established, but results of studies published to date suggest that it holds significant promise to function as a real time, early indicator of poor renal perfusion that may help with development of specific treatment protocols to prevent or decrease the severity of AKI.

Progressive anemia of prematurity is associated with a critical increase in cerebral oxygen extraction

BACKGROUND

Elevated cerebral fractional tissue oxygen extraction (cFTOE) is an adaptation to anemia of prematurity (AOP). cFTOE ≥0.4 is associated with brain injury in infants ≤30 weeks. This longitudinal study sought to investigate the utility of cFTOE in the evaluation of AOP.

METHODS

Infants ≤30 weeks estimated gestational age (EGA) underwent weekly hemoglobin, cerebral saturation, and pulse oximetry recordings from the second through 36 weeks post-menstrual age (PMA). Recordings were excluded if they were under 1 h or if hemoglobin was not measured within 7 days of recording. Mean cFTOE was calculated for each recording. Statistical analysis used linear mixed-effects modeling and receiver operating characteristic analysis.

RESULTS

144 recordings from 39 infants (mean EGA 27.6 ± 2.2 weeks, BW 1139 ± 286 g) were included of whom 39% (15/39) were transfused. The mean recording length was 2.8 ± 1.3 h. There was a significant negative correlation between hemoglobin and cFTOE (R = -0.423, p ≤.001). In a multivariate model, adjusting for EGA, PMA, and patent ductus arteriosus treatment the AUC was 0.821. A critical increase in cFTOE occurred at a hemoglobin level of 9.6 g/dL.

CONCLUSIONS

AOP is associated with a critical increase in cFTOE that occurs at a significantly higher hemoglobin level than standard clinical thresholds for transfusion.

The effects of ventilation on left-to-right shunt and regional cerebral oxygen saturation: a self-controlled trial

BACKGROUND

Increase of pulmonary vascular resistance (PVR) is an efficient method of modulating pulmonary and systemic blood flows (Qp/Qs) for patients with left-to-right (L-R) shunt, and is also closely associated with insufficient oxygen exchange for pulmonary hypoperfusion. So that it might be a preferred regime of maintaining arterial partial pressure of carbon dioxide tension (PaCO₂) within an optimal boundary via ventilation management in congenital heart disease (CHD) patients for the inconvenient measure of the PVR and Qp/Qs. However, the appropriate range of PaCO₂ and patient-specific mechanical ventilation settings remain controversial for CHD children with L-R shunt.

METHODS

Thirty-one pediatric patients with L-R shunt, 1-6 yr of age, were included in this observation study. Patients were ventilated with tidal volume (V_T) of 10, 8 and 6 ml/kg in sequence, and 15 min stabilization period for individual V_T. The velocity time integral (VTI) of L-R shunt, pulmonary artery (PA) and descending aorta (DA) were measured with transesophageal echocardiography (TEE) after an initial 15 min stabilization period for each V_T, with arterial blood gas analysis. Near-infrared spectroscopy sensor were positioned on the surface of the bilateral temporal artery to monitor the change in regional cerebral oxygen saturation (rScO₂).

RESULTS

PaCO₂ was 31.51 ± 0.65 mmHg at V_T 10 ml/kg vs. 37.15 ± 0.75 mmHg at V_T 8 ml/kg (P < 0.03), with 44.24 ± 0.99 mmHg at V_T 6 ml/kg significantly higher than 37.15 ± 0.75 mmHg at V_T 8 ml/kg. However, PaO₂ at a V_T of 6 ml/kg was lower than that at a V_T of 10 ml/kg (P = 0.05). Meanwhile, 72% (22/31) patients had PaCO₂ in the range of 40-50 mmHg at V_T 6 ml/kg. VTI of L-R shunt and PA at V_T 6 ml/kg were lower than that at V_T of 8 and 10 ml/kg (P < 0.05). rScO₂ at a V_T of 6 ml/kg was higher than that at a V_T of 8 and 10 ml/kg (P < 0.05), with a significantly correlation between rScO₂ and PaCO₂ (r = 0.53). VTI of PA in patients with defect diameter > 10 mm was higher that that in patients with defect diameter ≤ 10 mm.

CONCLUSIONS

Maintaining PaCO₂ in the boundary of 40-50 mmHg with V_T 6 ml/kg might be a feasible ventilation regime to achieve better oxygenation for patients with L-R shunt. Continue raising PaCO₂ should be careful.

TRAIL REGISTRATION

Clinical Trial Registry of China (http://www.chictr.org.cn) identifier: ChiCTR-OOC-17011338 , prospectively registered on May 9, 2017.

Cerebral perfusion and assessing hemodynamic significance for patent ductus arteriosus using near infrared red spectroscopy in very low birth weight infants

INTRODUCTION/OBJECTIVE

To study the impact of hemodynamically significant patent ductus arteriosus (hsPDA), using near infrared red spectroscopy (NIRS) regional cerebral (SrO₂), renal (RrO₂) saturation measurements, and fractional tissue oxygenation extraction (FTOE) before and after medical and/or surgical treatment.

METHODS

Prospective cohort study of very low birth weight (VLBW) preterm infants with hsPDA requiring treatment from March 2014 to December 2016 in a tertiary Neonatal Intensive Care Unit in Singapore. NIRS was applied at diagnosis until 24-48 h after the last dose of ibuprofen or postsurgical ligation. All PDAs were documented to be closed by echocardiography. Post-treatment values (control group) were compared against pretreatment values.

RESULTS

Twenty-nine infants were studied, with mean gestational age of 26.7 weeks and birth weight of 956 g. Median day of life of PDA diagnosis was 4. Seven infants (24.1%) underwent PDA ligation. There was significant reduction in FTOE before treatment till after last dose of medication or ligation by a mean difference of 7.27% (p < .05). Reduction in FTOE was also found between the first dose of medication till after the last dose or ligation. Cerebral SrO₂ significantly increased between first dose of medication till last dose of medication by a mean difference of 3.09% (p = .034). RrSO2 values were not significantly affected. No correlation between NIRS values and PDA size was found.

CONCLUSIONS

Significant increase in cerebral SrO₂ and reduction in FTOE by NIRS post PDA closure in hemodynamically significant PDAs suggest that PDA closure may reduce cerebral hypoxia burden.

Haemodynamic Instability and Brain Injury in Neonates Exposed to Hypoxia⁻Ischaemia

Brain injury in the asphyxic newborn infant may be exacerbated by delayed restoration of cardiac output and oxygen delivery. With increasing severity of asphyxia, cerebral autoregulatory responses are compromised. Further brain injury may occur in association with high arterial pressures and cerebral blood flows following the restoration of cardiac output. Initial resuscitation aims to rapidly restore cardiac output and oxygenation whilst mitigating the impact of impaired cerebral autoregulation. Recent animal studies have indicated that the current standard practice of immediate umbilical cord clamping prior to resuscitation may exacerbate injury. Resuscitation prior to umbilical cord clamping confers several haemodynamic advantages. In particular, it retains the low-resistance placental circuit that mitigates the rebound hypertension and cerebrovascular injury. Prolonged cerebral hypoxia–ischaemia is likely to contribute to further perinatal brain injury, while, at the same time, tissue hyperoxia is associated with oxidative stress. Efforts to monitor and target cerebral flow and oxygen kinetics, for example, using near-infrared spectroscopy, are currently being evaluated and may facilitate development of novel resuscitation approaches.

Cerebral Oxygenation During Neonatal Intubation-Ancillary Study of the Prettineo-Study

Purpose: This study aimed to describe cerebral Near InfraRed Spectroscopy (NIRS) profiles during neonatal intubation using two different premedication regimens. Methods: Neonates requiring non-emergency intubation were enrolled in an ancillary study, conducted in two French Neonatal Intensive Care Units participating in a larger on-going multicenter, double blind, randomized, controlled trial. Patients were randomly assigned to the "atropine-propofol" (Prop) group or the "atropine-atracurium-sufentanil" (SufTrac) group. Regional cerebral oxygen saturation (rScO₂), pulse oxymetry (SpO₂), mean arterial blood pressure (MABP), and transcutaneous partial pressure of carbon dioxide (TcPCO₂) were collected at 9 predefined time points from 1 min before to 60 min after the first drug injection. The two primary outcomes were a decrease in rScO₂ value >20% from baseline and a decrease in fractional cerebral tissue oxygen extraction (FTOE) value >10% from baseline, at any time point. Secondary outcomes included physiological parameters changes over time and correlations between mean arterial blood pressure, and FTOE at different time points. Descriptive results were obtained and exploratory statistical analyses were performed for 24 included patients. Results: rScO₂ decreased in 5/11 (46%) infants from the Prop group and 10/13 (77%) from the SufTrac group (p = 0.11); FTOE decreased in 10/11 (91%) infants from the Prop group, and 12/13 (92%) from the SufTrac group (p = 0.90). rScO₂ values decreased over time in both groups, whereas FTOE's pattern appeared more stable. SpO₂ and transcutaneous TcPCO₂ seemed more preserved in the Prop group while MABP seemed more preserved in the SufTrac group. No important correlation was observed between MABP and FTOE (r = 0.08 to 0.12 across the time points). Conclusion: Our results suggest a frequent decrease in cerebral oxygenation without obvious impairment in cerebral autoregulation during neonatal intubation with premedication. This study confirms the feasibility and the informative value of cerebral NIRS monitoring in this setting. Clinical Trial Registration: www.ClinicalTrials.gov, identifier NCT02700893.

Anemia of prematurity and cerebral near-infrared spectroscopy: should transfusion thresholds in preterm infants be revised?

OBJECTIVE

To determine the impact of progressive anemia of prematurity on cerebral regional saturation (C-rSO₂) in preterm infants and identify the hemoglobin threshold below which a critical decrease (>2SD below the mean) in C-rSO₂ occurs.

STUDY DESIGN

In a cohort of infants born ≤30 weeks EGA, weekly C-rSO₂ data were prospectively collected from the second week of life through 36 weeks post-menstrual age (PMA). Clinically obtained hemoglobin values were noted at the time of recording. Recordings were excluded if they were of insufficient duration (<1 h) or if the hemoglobin was not measured within 7 days. Statistical analysis was performed using a linear mixed effects-model and ROC analysis. ROC analysis was used to determine the threshold of anemia, where C-rSO₂ critically decreased >2SD below the mean normative value (<55%) in preterm infants.

RESULTS

In total 253 recordings from 68 infants (mean EGA 26.9 ± 2.1 weeks, BW 1025 ± 287 g, 49% male) were included. Approximately 29 out of 68 infants (43%) were transfused during hospitalization. Mixed-model statistical analysis adjusting for EGA, BW, and PMA revealed a significant association between decreasing hemoglobin and C-rSO₂ (p < 0.01) in transfusion-naive infants but not in transfused infants. In the transfusion naive group, using ROC analysis demonstrated a threshold hemoglobin of 9.5 g/dL (AUC 0.81, p < 0.01) for critical cerebral desaturation in preterm infants.

CONCLUSIONS

In transfusion-naive preterm infants, worsening anemia was associated with a progressive decrease in cerebral saturations. Analysis identified a threshold hemoglobin of 9.5 g/dL below which C-rSO₂ dropped >2SD below the mean.

Oxygen Therapy in the Delivery Room: What Is the Right Dose?

Oxygen is the most commonly used medicine used during neonatal resuscitation in the delivery room. Oxygen therapy in delivery room should be used judiciously to avoid oxygen toxicity while delivering sufficient oxygen to prevent hypoxia. Measurement of appropriate oxygenation relies on pulse oximetry, but adequate ventilation and perfusion are equally important for oxygen delivery. In this article, we review oxygenation while transitioning from fetal to neonatal life, the importance of appropriate oxygen therapy, its measurement in the delivery room, and current recommendations for oxygen therapy and its limitations.

Cerebral oxygenation during umbilical arterial blood sampling in very low birth weight neonates

OBJECTIVE

Umbilical arterial blood sampling (UABS) has been associated with cerebral oxygen saturation (CrSO₂) decrements in very low birth weight (VLBW) neonates. We sought to determine patient- and UABS procedure-related factors contributing to this effect.

STUDY DESIGN

In this prospective cohort study, cerebral near-infrared spectroscopy was performed during UABS procedures in VLBW neonates. Analyses were conducted to determine subject- and procedure-related factors correlating with CrSO₂ decrements.

RESULT

Thirty subjects (mean (±SD) 27 ± 2 week GA and 1058 ± 279 g BW) underwent 84 UABS procedures between 5 and 183 postnatal hours. Six (20%) experienced CrSO₂ decrements, less than previously reported. Subjects with CrSO₂ decrements had earlier GA and lower BW, though these were not statistically significant differences. CrSO₂ decrements occurred with lower pre- and post-UABS pulse oximetry (p = 0.004; p < 0.001), lower arterial oxygen partial pressure (p < 0.001), lower baseline CrSO₂ (p = 0.01), and faster "priming" blood reinfusion (p = 0.03) and saline flush (p = 0.02).

CONCLUSION

UABS procedures appear to be associated with CrSO₂ decrements more commonly among VLBW neonates already experiencing disturbances in cerebral oxygen delivery-consumption balance. Shorter durations of UABS procedural components may contribute to CrSO₂ decrements.

Comparison of tissue oximeters on a liquid phantom with adjustable optical properties: an extension

Cerebral near-infrared spectroscopy (NIRS) oximetry may help clinicians to improve patient treatment. However, the application of NIRS oximeters is increasingly causing confusion to the users due to the inconsistency of tissue oxygen haemoglobin saturation (StO2) readings provided by different oximeters. To establish a comparability of oximeters, in our study we performed simultaneous measurements on the liquid phantom mimicking properties of neonatal heads and compared the tested device to a reference NIRS oximeter (OxiplexTS). We evaluated the NIRS oximeters FORE-SIGHT, NIRO and SenSmart, and reproduced previous results with the INVOS and OxyPrem v1.3 oximeters. In general, linear relationships of the StO2 values with respect to the reference were obtained. Device specific hypoxic and hyperoxic thresholds (as used in the SafeBoosC study, www.safeboosc.eu) and a table allowing for conversion of StO2 values are provided.

Treating Hypotension in Preterm Neonates With Vasoactive Medications

Preterm neonates often have hypotension which may be due to various etiologies. While it is controversial to define hypotension in preterm neonates, various vasoactive medications are commonly used to provide the cardiovascular support to improve the blood pressure, cardiac output, or to treat shock. However, the literature on the systemic and regional hemodynamic effects of these antihypotensive medications in neonates is deficient and incomplete, and cautious translation of findings from other clinical populations and animal studies is required. Based on a literature search on published reports, meta-analytic reviews, and selected abstracts, this review discusses the current available information on pharmacologic actions, clinical effects, and side effects of commonly used antihypotensive medications including dopamine, dobutamine, epinephrine, norepinephrine, vasopressin, and milrinone in preterm neonates.

Measuring Near-Infrared Spectroscopy Derived Cerebral Autoregulation in Neonates: From Research Tool Toward Bedside Multimodal Monitoring

Introduction: Cerebral autoregulation (CAR), the ability of the human body to maintain cerebral blood flow (CBF) in a wide range of perfusion pressures, can be calculated by describing the relation between arterial blood pressure (ABP) and cerebral oxygen saturation measured by near-infrared spectroscopy (NIRS). In literature, disturbed CAR is described in different patient groups, using multiple measurement techniques and mathematical models. Furthermore, it is unclear to what extent cerebral pathology and outcome can be explained by impaired CAR. Aim and methods: In order to summarize CAR studies using NIRS in neonates, a systematic review was performed in the PUBMED and EMBASE database. To provide a general overview of the clinical framework used to study CAR, the different preprocessing methods and mathematical models are described and explained. Furthermore, patient characteristics, definition of impaired CAR and the outcome according to this definition is described organized for the different patient groups. Results: Forty-six articles were included in this review. Four patient groups were established: preterm infants during the transitional period, neonates receiving specific medication/treatment, neonates with congenital heart disease and neonates with hypoxic-ischemic encephalopathy (HIE) treated with therapeutic hypothermia. Correlation, coherence and transfer function (TF) gain are the mathematical models most frequently used to describe CAR. The definition of impaired CAR is depending on the mathematical model used. The incidence of intraventricular hemorrhage in preterm infants is the outcome variable most frequently correlated with impaired CAR. Hypotension, disease severity, dopamine treatment, injury on magnetic resonance imaging (MRI) and long term outcome are associated with impaired CAR. Prospective interventional studies are lacking in all research areas. Discussion and conclusion: NIRS derived CAR measurement is an important research tool to improve knowledge about central hemodynamic fluctuations during the transitional period, cerebral pharmacodynamics of frequently used medication (sedatives-inotropes) and cerebral effects of specific therapies in neonatology. Uniformity regarding measurement techniques and mathematical models is needed. Multimodal monitoring databases of neonatal intensive care patients of multiple centers, together with identical outcome parameters are needed to compare different techniques and make progress in this field. Real-time bedside monitoring of CAR, together with conventional monitoring, seems a promising technique to improve individual patient care.

Monitoring Circulation During Transition in Extreme Low Gestational Age Newborns: What's on the Horizon?

Echocardiography and near-infrared spectroscopy have significantly changed our view on hemodynamic transition of the extreme preterm infant. Instead of focusing on maintaining an arbitrary target value of blood pressure, we aim for circulatory well-being by a comprehensive holistic assessment of markers of cardiovascular instability. Most of these clinical and biochemical indices are influenced by transition itself and remain poor discriminators to identify patients with a potential need for therapeutic intervention. At the same time, the evolution in data capturing and storage has led to a change in our approach to monitor vital parameters. Continuous trend monitoring has become more and more relevant. By using signal extraction methods, changes in trends over time can be quantified. In this review, we will discuss the impact of these innovations on the current monitoring practices and explore some of the potential benefits these techniques may have in improving real-time detection of extreme low birth weight infants at risk for morbidity related to impaired hemodynamic transition.

Reducing Brain Injury of Preterm Infants in the Delivery Room

Cerebrovascular injury is one of the major detrimental consequences of preterm birth. Recent studies have focused their attention on factors that contribute to the development of brain lesions immediately after birth. Among those factors, hypothermia and lower cerebral oxygen saturation during delivery room resuscitation and high tidal volumes delivered during respiratory support are associated with increased risk of severe neurologic injury. In preterm infants, knowledge about causes and prevention of brain injury must be applied before and at birth. Preventive and therapeutic approaches, including correct timing of cord clamping, monitoring of physiological changes during delivery room resuscitation using pulse oximetry, respiratory function monitoring, near infrared spectroscopy, and alpha EEG, may minimize brain injury, Furthermore, postnatal administration of caffeine or other potential novel treatments (e.g., proangiogenic therapies, antioxidants, hormones, or stem cells) might improve long-term neurodevelopmental outcomes in preterm infants.

Cerebral NIRS patterns in late preterm and very preterm infants becoming late preterm

BACKGROUND

Near Infrared Spectroscopy (NIRS) has been proposed as a useful, noninvasive monitoring technique providing reliable information about central nervous system (CNS) oximetry and function. Recently, brain damage has been reconsidered as a dynamic process evolving over the weeks of gestation. We therefore investigated NIRS cerebral pattern differences between healthy late preterm infants (LPTo) and very preterm infants becoming late preterm (LPT).

METHODS

We conducted an observational study in 40 healthy late preterm infants, matched for gestational age at monitoring, of whom 20 where LPTo and 20 LPT. Clinical, diagnostic and laboratory monitoring procedures and cerebral oximetry (crSO₂) and function (cFTOE) were recorded on admission into the study.

RESULTS

No significant differences (p > .05, for all) were found between groups regarding clinical, diagnostic or laboratory parameters. Higher crSO₂ and lower cFTOE (p < .001, for both) were found in the LPTo group.

CONCLUSIONS

Our results, showing impaired oximetry and function of CNS in LPT, offer additional support to NIRS parameters as a useful tool for longitudinal CNS monitoring of very preterm infants becoming LPT. Future studies correlating NIRS variables and long-term neurological outcome in LPT are needed to elucidate the concept of dynamic brain damage pathogenesis.

Decreased oxygen saturation levels in neonates with transposition of great arteries: Impact on appearance of cerebral veins in susceptibility-weighted imaging

Purpose of this study was to investigate a potential correlation between the pattern of cerebral veins (CV) on susceptibility-weighted imaging (SWI) and blood oxygen saturation, as well as preoperative brain injury, in neonates with transposition of the great arteries (TGA). Eleven neonates with TGA underwent MRI preoperatively, including SWI, T1- and T2-weighted scans. Images were retrospectively evaluated and appearance of CV was graded from 0 (normal appearance) to 3 (severe prominent appearance). White matter injuries (WMI) and strokes were analysed. Results were correlated with preductal arterial oxygen saturation. As findings one subject showed a normal CV appearance (grade 0) whereas 10 showed pathological prominent CV (grades 1–3); median 2. Mean oxygen saturation ranged between 67.5% and 89.0% (median 81.0%). CV grade and mean oxygen saturation correlated significantly (p = 0.011). WMI were absent in 5 cases, mild in 4, and moderate in 2 cases. We conclude, that SWI has the potential to be used to estimate the current hypoxic burden on brain tissue in TGA newborns by assessing the prominence of the CV.