Reference Ranges for Arterial Oxygen Saturation, Heart Rate, and Cerebral Oxygen Saturation during Immediate Postnatal Transition in Neonates Born Extremely or Very Preterm.

OBJECTIVE: To define percentile charts for arterial oxygen saturation (SpO2), heart rate (HR), and cerebral oxygen saturation (crSO2) during the first 15 minutes after birth in neonates born very or extremely preterm and with favorable outcome. STUDY DESIGN: We conducted a secondary-outcome analysis of neonates born preterm included in the Cerebral regional tissue Oxygen Saturation to Guide Oxygen Delivery in preterm neonates during immediate transition after birth III (COSGOD III) trial with visible cerebral oximetry measurements and with favorable outcome, defined as survival without cerebral injuries until term age. We excluded infants with inflammatory morbidities within the first week after birth. SpO2 was obtained by pulse oximetry, and electrocardiogram or pulse oximetry were used for measurement of HR. crSO2 was assessed with near-infrared spectroscopy. Measurements were performed during the first 15 minutes after birth. Percentile charts (10th to 90th centile) were defined for each minute. RESULTS: A total of 207 neonates born preterm with a gestational age of 29.7 (23.9-31.9) weeks and a birth weight of 1200 (378-2320) g were eligible for analyses. The 10th percentile of SpO2 at minute 2, 5, 10, and 15 was 32%, 52%, 83%, and 85%, respectively. The 10th percentile of HR at minute 2, 5, 10, and 15 was 70, 109, 126, and 134 beats/min, respectively. The 10th percentile of crSO2 at minute 2, 5, 20, and 15 was 15%, 27%, 59%, and 63%, respectively. CONCLUSIONS: This study provides new centile charts for SpO2, HR, and crSO2 for neonates born extremely or very preterm with favorable outcome. Implementing these centiles in guiding interventions during the stabilization process after birth might help to more accurately target oxygenation during postnatal transition period.

Sustained Inflation Versus Intermittent Positive Pressure Ventilation for Preterm Infants at Birth: Respiratory Function and Vital Sign Measurements.

OBJECTIVE: To characterize respiratory function monitor (RFM) measurements of sustained inflations and intermittent positive pressure ventilation (IPPV) delivered noninvasively to infants in the Sustained Aeration of Infant Lungs (SAIL) trial and to compare vital sign measurements between treatment arms. STUDY DESIGN: We analyzed RFM data from SAIL participants at 5 trial sites. We assessed tidal volumes, rates of airway obstruction, and mask leak among infants allocated to sustained inflations and IPPV, and we compared pulse rate and oxygen saturation measurements between treatment groups. RESULTS: Among 70 SAIL participants (36 sustained inflations, 34 IPPV) with RFM measurements, 40 (57%) were spontaneously breathing prior to the randomized intervention. The median expiratory tidal volume of sustained inflations administered was 5.3 mL/kg (IQR 1.1-9.2). Significant mask leak occurred in 15% and airway obstruction occurred during 17% of sustained inflations. Among 34 control infants, the median expiratory tidal volume of IPPV inflations was 4.3 mL/kg (IQR 1.3-6.6). Mask leak was present in 3%, and airway obstruction was present in 17% of IPPV inflations. There were no significant differences in pulse rate or oxygen saturation measurements between groups at any point during resuscitation. CONCLUSION: Expiratory tidal volumes of sustained inflations and IPPV inflations administered in the SAIL trial were highly variable in both treatment arms. Vital sign values were similar between groups throughout resuscitation. Sustained inflation as operationalized in the SAIL trial was not superior to IPPV to promote lung aeration after birth in this study subgroup. TRIAL REGISTRATION: Clinicaltrials.gov: NCT02139800.

Early Cardiac and Cerebral Hemodynamics with Umbilical Cord Milking Compared with Delayed Cord Clamping in Infants Born Preterm.

OBJECTIVE: To evaluate changes in cerebral oxygenation, peripheral arterial oxygenation, respiratory status, and administered fraction of inspired oxygen during the first 10 minutes of life in premature infants receiving umbilical cord milking compared with delayed cord clamping (DCC). STUDY DESIGN: Premature infants born at 230/7 to 276/7 weeks of gestation were randomized to umbilical cord milking or DCC. A near infrared spectroscopy sensor, pulse oximeter, and electrocardiogram electrodes were placed. Pulse rate, cerebral tissue oxygenation, peripheral oxygen saturation, airway pressure, and fraction of inspired oxygen were collected for 10 minutes in the delivery room. Longitudinal models were used to compare effects of umbilical cord milking and DCC. RESULTS: Fifty-six infants had cerebral oximetry and advanced monitoring at birth. There was an increased incidence of severe intraventricular hemorrhage in infants who received umbilical cord milking compared with DCC (P = .0211). Longitudinal models suggested that peripheral oxygen saturation was higher in the umbilical cord milking group in the first 4 minutes (P = .0221) and that mean airway pressures were lower in the umbilical cord milking group after the first 7 minutes (P = .0072). No statistical differences were observed for fraction of inspired oxygen, cerebral tissue oxygenation, or heart rates. CONCLUSIONS: The data suggest that the rapid transfer of blood during umbilical cord milking may facilitate lung expansion with improved pulmonary blood flow, but may also increase cerebral blood flow, resulting in severe intraventricular hemorrhage. TRIAL REGISTRATION: ClinicalTrials.gov: NCT03145142.

Blood Glucose and Cerebral Tissue Oxygenation Immediately after Birth-An Observational Study.

OBJECTIVE: To assess a possible association of blood glucose concentration with cerebral regional oxygen saturation (crSO2) and cerebral fractional tissue oxygen extraction (cFTOE) in neonates born at term and preterm 15 minutes after birth. STUDY DESIGN: A post-hoc analysis of secondary outcome measures of 2 prospective observational studies was performed. Neonates born at term and preterm via cesarean delivery were included if cerebral near-infrared spectroscopy measurements were performed during the immediate transition after birth and blood glucose concentrations were measured at 15-20 minutes after birth. Arterial oxygen saturation and heart rate were measured with pulse oximetry. cFTOE was calculated from arterial oxygen saturation and crSO2 values. crSO2 and cFTOE 15 minutes after birth were correlated with blood glucose concentrations. RESULTS: Seventy-five infants were included. In 50 neonates born at term, crSO2 and cFTOE 15 minutes after birth were 83 ± 7.7% and 0.14 ± 0.08, respectively. In 25 neonates born preterm, crSO2 and cFTOE 15 minutes after birth were 80.2 ± 12.1%, and 0.15 ± 0.1, respectively. crSO2 and cFTOE correlated significantly with blood glucose concentrations in neonates born at term and preterm. Increasing blood glucose concentrations were associated with decreasing crSO2 in neonates born at term (q = -0.35, P = .01) and neonates born preterm (q = -0.69, P = .01) and with increasing cFTOE in neonates born at term (q = 0.31, P = .03) and neonates born preterm (q = 0.67, P = .01). CONCLUSIONS: Blood glucose concentration was associated with cerebral oxygenation during the immediate transition after birth in neonates born at term and preterm.

Oxygen Saturation and Heart Rate Ranges in Very Preterm Infants Requiring Respiratory Support at Birth.

OBJECTIVE: To evaluate the changes in preductal oxygen saturation (SpO2) and heart rate in preterm infants receiving continuous positive airway pressure (CPAP) and/or positive-pressure ventilation (PPV) at birth. STUDY DESIGN: A prospective observational study at birth of infants aged <32 weeks separated into 2 gestational age (GA) groups: 230/7-276/7 weeks (group 1) and 280/7-316/7 weeks (group 2). Infants received delayed cord clamping (DCC) in accordance with institutional protocol. CPAP and/or PPV was applied at the clinical team's discretion. SpO2 and heart rate were recorded every minute for 10 minutes. Preductal SpO2 was targeted according to published nomograms. For heart rate, the goal was to maintain a stable heart rate >100 bpm. RESULTS: The study cohort comprised 96 group 1 infants (mean GA, 26 ± 1 weeks; mean birth weight, 818 ± 208 g) and 173 group 2 infants (mean GA, 30 ± 1 weeks; mean birth weight, 1438 ± 374 g). In general, infants requiring respiratory support reached target values for heart rate and SpO2 more slowly than the published nomograms for spontaneously breathing preterm infants without respiratory support. Infants receiving CPAP reached SpO2 and heart rate targets faster than infants receiving PPV. In group 1, but not group 2 infants, DCC resulted in higher SpO2 and heart rate. CONCLUSION: SpO2 and heart rate do not quickly and reliably reach the values achieved by spontaneously breathing preterm infants not requiring respiratory support.

Exhaled Carbon Dioxide and Neonatal Breathing Patterns in Preterm Infants after Birth.

OBJECTIVES: To examine the amount of exhaled carbon dioxide (ECO2) with different breathing patterns in spontaneously breathing preterm infants after birth. STUDY DESIGN: Preterm infants had a facemask attached to a combined carbon dioxide/flow sensor placed over their mouth and nose to record ECO2 and gas flow. A breath-by-breath analysis of the first 5 minutes of the recording was performed. RESULTS: Thirty spontaneously breathing preterm infants, gestational age (mean ± SD) 30 ± 2 weeks and birth weight 1635 ± 499 g were studied. ECO2 from normal breaths and slow expirations was significantly larger than with other breathing patterns (P < .001). ECO2 per breath also increased with gestational age P < .001. The expiratory hold pattern was the most prevalent breathing pattern both during the first minute of recording and overall. Breathing pattern proportions also varied by gestational age. Finally, ECO2 from the fifth minute of recording was significantly greater than that produced during the first 4 minutes of recording (P ≤ .029). CONCLUSIONS: ECO2 varies with different breathing patterns and increases with gestational age and over time. ECO2 may be an indicator of lung aeration and that postnatal ECO2 monitoring may be useful in preterm infants in the delivery room.

Spontaneously Breathing Preterm Infants Change in Tidal Volume to Improve Lung Aeration Immediately after Birth.

OBJECTIVE: To examine the temporal course of lung aeration at birth in preterm infants <33 weeks gestation. STUDY DESIGN: The research team attended deliveries of preterm infants <33 weeks gestation at the Royal Alexandra Hospital. Infants who received only continuous positive airway pressure were eligible for inclusion. A combined carbon dioxide (CO2) and flow-sensor was placed between the mask and the ventilation device. To analyze lung aeration patterns during spontaneous breathing, tidal volume (VT), and exhaled CO2 (ECO2) were recorded for the first 100 breaths. RESULTS: Thirty preterm infants were included with a total of 1512 breaths with mask leak <30%. Mean (SD) gestational age and birth weight was 30 (1) weeks and 1478 (430) g. Initial VT and ECO2 for the first 30 breaths was 5-6 mL/kg and 15-22 mm Hg, respectively. VT and ECO2 increased over the next 20 breaths to 7-8 mL/kg and 25-32 mm Hg, respectively. For the remaining observation period VT decreased to 4-6 mL/kg and ECO2 continued to increase to 35-37 mm Hg. CONCLUSIONS: Preterm infants begin taking deeper breaths approximately 30 breaths after initiating spontaneous breathing to inflate their lungs. Concurrent CO2 removal rises as alveoli are recruited. Lung aeration occurs in 2 phases: initially, large volume breaths with poor alveolar aeration followed by smaller breaths with elimination of CO2 as a consequence of adequate aeration.

Exhaled carbon dioxide in healthy term infants immediately after birth.

OBJECTIVE: To measure exhaled carbon dioxide (ECO2) in term infants immediately after birth. STUDY DESIGN: Infants >37 weeks gestation born at The Royal Women's Hospital, Melbourne, Australia were eligible. A combined flow sensor and mainstream carbon dioxide (CO2) analyzer was placed in series proximal to a facemask to measure ECO2 and tidal volumes in the first 120 seconds after birth. RESULTS: Term infants (n = 20) with a mean (SD) birth weight of 2976 (697) g and gestational age of 38 (2) weeks were included. Infants took a median (range) 3 (1-8) breaths before ECO2 was detected. The median (range) of maximum ECO2 was 51 (40-73) mm Hg at 70 (21-106) seconds after birth. Within the first 10 breaths, CO2 increased from 0-27 (22-34) mm Hg. The median (IQR) tidal volume during the breaths without CO2 was 1.2 (0.8-3.1) mL/kg compared with 7.3 (3.2-10.9) mL/kg during the first 10 breaths where CO2 was exhaled. CONCLUSIONS: The first breaths for an infant after birth did not contain ECO2. With aeration of the distal gas exchange regions, tidal volume and ECO2 significantly increased. ECO2 can be used to monitor lung aeration immediately after birth.

Tidal volumes in spontaneously breathing preterm infants supported with continuous positive airway pressure.

OBJECTIVE: To describe changes in tidal volume (VT) and their correlation to changes in oxygen saturation and heart rate in spontaneously breathing preterm infants immediately after birth. STUDY DESIGN: In this prospective observational, 2-center study, a flow sensor was attached to the facemask of spontaneously breathing infants born at <37 weeks' gestational age who received continuous positive airway pressure (CPAP) immediately after birth. Respiratory function, heart rate, and oxygen saturation were continuously recorded during spontaneous breathing. RESULTS: Fifty-five infants (mean [SD] gestational age 31 [26-36] weeks and birth weight 1647 [500] g) received mask CPAP in the delivery room. CPAP was started at a median (IQR) 90 (60-118) seconds after birth and was delivered for 720 (300-900) seconds. Median VT ranged between 4.2 and 5.8 mL/kg with the individual VT varied between 0.9 and 19.8 mL/kg. Overall, VT increased over the first few minutes after birth and decreased thereafter. The increase in saturation after birth lagged behind the published normal ranges for spontaneously breathing preterm infants without CPAP. CONCLUSIONS: The 50th percentile for spontaneous VT in preterm infants during mask CPAP ranged from 4.2 to 5.8 mL/kg, with wide individual variation observed in the first minutes after birth. Preterm infants requiring CPAP after birth may take longer to achieve so-called "normal" saturation targets.

Reference ranges for regional cerebral tissue oxygen saturation and fractional oxygen extraction in neonates during immediate transition after birth.

OBJECTIVE: To define reference ranges for regional cerebral tissue oxygen saturation (crSO2) and regional cerebral fractional tissue oxygen extraction (cFTOE) during the first 15 minutes after birth in neonates requiring no medical support. STUDY DESIGN: The crSO2 was measured using near infrared spectroscopy (Invos 5100 cerebral/somatic oximeter monitor; Somanetics Corp, Troy, Michigan) during the first 15 minutes after birth for term and preterm neonates. The near infrared spectroscopy sensor was placed on the left forehead. Peripheral oxygen saturation and heart rate were continuously measured by pulse oximetry, and cFTOE was calculated. Neonates were excluded if they required any medical support. RESULTS: A total of 381 neonates were included: 82 term neonates after vaginal delivery, 272 term neonates after cesarean delivery, and 27 preterm neonates after cesarean delivery. In all neonates, median (10th-90th percentiles) crSO2 was 41% (23-64) at 2 minutes, 68% (45-85) at 5 minutes, 79% (65-90) at 10 minutes, and 77% (63-89) at 15 minutes of age. In all neonates, median (10th-90th percentiles) cFTOE was 33% (11-70) at 2 minutes, 21% (6-45) at 5 minutes, 15% (5-31) at 10 minutes, and 18% (7-34) at 15 minutes of age. CONCLUSION: We report reference ranges of crSO2 and cFTOE in neonates requiring no medical support during transition immediately after birth. The use of cerebral oxygenation monitoring and use of these reference ranges in neonates during transition may help to guide oxygen delivery and avoid cerebral hypo-oxygenation and hyperoxygenation.

Respiratory function monitor guidance of mask ventilation in the delivery room: a feasibility study.

OBJECTIVE: To investigate whether using a respiratory function monitor (RFM) during mask resuscitation of preterm infants reduces face mask leak and improves tidal volume (V(T)). STUDY DESIGN: Infants receiving mask resuscitation were randomized to have the display of an RFM (airway pressure, flow, and V(T) waves) either visible or masked. RESULT: Twenty-six infants had the RFM visible, and 23 had the RFM masked. The median mask leak was 37% (IQR, 21%-54%) in the visible RFM group and 54% (IQR, 37%-82%) in the masked RFM group (P = .01). Mask repositioning was done in 19 infants (73%) of the visible group and in 6 infants (26%) of the masked group (P = .001). The median expired V(T) was similar in the 2 groups. Oxygen was provided to 61% of the visible RFM group and 87% of the RFM masked group (P = .044). Continuous positive airway pressure use was greater in the visible RFM group (73% vs 43%; P = .035). Intubation in the delivery room was done in 21% of the visible group and in 57% of the masked group (P = .035). CONCLUSION: Using an RFM was associated with significantly less mask leak, more mask adjustments, and a lower rate of excessive V(T).

Oxygenation with T-piece versus self-inflating bag for ventilation of extremely preterm infants at birth: a randomized controlled trial.

OBJECTIVE: To investigate whether infants < 29 weeks gestation who receive positive pressure ventilation (PPV) immediately after birth with a T-piece have higher oxygen saturation (SpO2) measurements at 5 minutes than infants ventilated with a self inflating bag (SIB). STUDY DESIGN: Randomized, controlled trial of T-piece or SIB ventilation in which SpO2 was recorded immediately after birth from the right hand/wrist with a Masimo Radical pulse oximeter, set at 2-second averaging and maximum sensitivity. All resuscitations started with air. RESULTS: Forty-one infants received PPV with a T-piece and 39 infants received PPV with a SIB. At 5 minutes after birth, there was no significant difference between the median (interquartile range) SpO2 in the T-piece and SIB groups (61% [13% to 72%] versus 55% [42% to 67%]; P = .27). More infants in the T-piece group received oxygen during delivery room resuscitation (41 [100%] versus 35 [90%], P = .04). There was no difference in the groups in the use of continuous positive airway pressure, endotracheal intubation, or administration of surfactant in the delivery room. CONCLUSION: There was no significant difference in SpO2 at 5 minutes after birth in infants < 29 weeks gestation given PPV with a T-piece or a SIB as used in this study.