Connie Wong

Defining the reference range for oxygen saturation for infants after birth.

OBJECTIVE: The goal was to define reference ranges for pulse oxygen saturation (Spo2) values in the first 10 minutes after birth for infants who received no medical intervention in the delivery room. METHODS: Infants were eligible if a member of the research team was available to record Spo2 immediately after birth. Infants were excluded if they received supplemental oxygen or any type of assisted ventilation. Spo2 was measured with a sensor applied to the right hand or wrist as soon as possible after birth; data were collected every 2 seconds. RESULTS: We studied 468 infants and recorded 61650 Spo2 data points. The infants had a mean ± SD gestational age of 38 ± 4 weeks and birth weight of 2970 ± 918 g. For all 468 infants, the 3rd, 10th, 50th, 90th, and 97th percentile values at 1 minute were 29%, 39%, 66%, 87%, and 92%, respectively, those at 2 minutes were 34%, 46%, 73%, 91%, and 95%, and those at 5 minutes were 59%, 73%, 89%, 97%, and 98%. It took a median of 7.9 minutes (interquartile range: 5.0–10 minutes) to reach a Spo2 value of >90%. Spo2 values for preterm infants increased more slowly than those for term infants. We present percentile charts for all infants, term infants of ≥37 weeks, preterm infants of 32 to 36 weeks, and extremely preterm infants of <32 weeks. CONCLUSION: These data represent reference ranges for Spo2 in the first 10 minutes after birth for preterm and term infants.

Oxygen saturation and heart rate during delivery room resuscitation of infants <30 weeks gestation with air or 100% oxygen.

Background: Because of concerns about harmful effects of 100% oxygen on newborn infants, air has started to be used for resuscitation in the delivery room. Objective: To describe changes in preductal oxygen saturation (Spo2) and heart rate (HR) in the first 10 min after birth in very preterm infants initially resuscitated with 100% oxygen (OX100) or air (OX21). Patients and methods: In July 2006, policy changed from using 100% oxygen to air. Observations of Spo2 and HR before and after the change were recorded whenever a member of the research team was available to attend the birth. Results: There were 20 infants in the OX100 group and 106 in the OX21 group. In the OX100 group, Spo2 had risen to a median of 84% after 2 min and 94% by 5 min. In the OX21 group, median Spo2 was 31% at 2 min and 54% at 5 min. In the OX21 group, 92% received supplemental oxygen at a median of 5 min; the Spo2 rose to a median of 81% by 6 min. In the first 10 min after birth, 80% and 55% of infants in the OX100 and OX21 groups, respectively, had an Spo2 ⩾95%. Increases in HR over the first 10 min were very similar in the two groups. Conclusions: Most very preterm infants received supplemental oxygen if air was used for the initial resuscitation. In these infants, the use of backup 100% oxygen and titration against Spo2 resulted in a similar course to “normal” term and preterm infants. Of the infants resuscitated with 100% oxygen, 80% had Spo2 ⩾95% during the first 10 min. The HR changes in the two groups were very similar.

Changes in heart rate in the first minutes after birth

The normal range of heart rate (HR) in the first minutes after birth has not been defined. Objective To describe the HR changes of healthy newborn infants in the delivery room (DR) detected by pulse oximetry. Study Design All inborn infants were eligible and included if a member of the research team attended the birth. Infants were excluded if they received any form of medical intervention in the DR including supplemental oxygen, or respiratory support. HR was measured using a pulse oximeter (PO) with the sensor applied to the right hand or wrist immediately after birth. PO data (oxygen saturation, HR and signal quality) were downloaded every 2 sec and analysed only when the signal had no alarm messages (low IQ signal, low perfusion, sensor off, ambient light). Results Data from 468 infants with 61 650 data points were included. Infants had a mean (range) gestational age of 38 (25–42) weeks and birth weight 2970 (625–5135) g. At 1 min the median (IQR) HR was 96 (65–127) beats per min (bpm) rising at 2 min and 5 min to 139 (110–166) bpm and 163 (146–175) bpm respectively. In preterm infants, the HR rose more slowly than term infants. Conclusions The median HR was <100 bpm at 1 min after birth. After 2 min it was uncommon to have a HR <100 bpm. In preterm infants and those born by caesarean section the HR rose more slowly than term vaginal births.

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).

Breathing Patterns in Preterm and Term Infants Immediately After Birth

There is limited data describing how preterm and term infants breathe spontaneously immediately after birth. We studied spontaneously breathing infants ≥29 wk immediately after birth. Airway flow and tidal volume were measured for 90 s using a hot wire anemometer attached to a facemask. Twelve preterm and 13 term infants had recordings suitable for analysis. The median (interquartile range) proportion of expiratory braking was very high in both groups (preterm 90 [74–99] vs. term 87 [74–94]%; NS). Crying pattern was the predominant breathing pattern for both groups (62 [36–77]% vs. 64 [46–79]%; NS). Preterm infants showed a higher incidence of expiratory hold pattern (9 [4–17]% vs. 2 [0–6]%; p = 0.02). Both groups had large tidal volumes (6.7 [3.9] vs. 6.5 [4.1] mL/kg), high peak inspiratory flows (5.7 [3.8] vs. 8.0 [5] L/min), lower peak expiratory flow (3.6 [2.4] vs. 4.8 [3.2] L/min), short inspiration time (0.31 [0.13] vs. 0.32 [0.16] s) and long expiration time (0.93 [0.64] vs. 1.14 [0.86] s). Directly after birth, both preterm and term infants frequently brake their expiration, mostly by crying. Preterm infants use significantly more expiratory breath holds to defend their lung volume.

Use of 2-Channel Bedside Electroencephalogram Monitoring in Term-Born Encephalopathic Infants Related to Cerebral Injury Defined by Magnetic Resonance Imaging

OBJECTIVE. Single-channel amplitude-integrated electroencephalography has been shown to be predictive of neurodevelopmental outcome in term infants with hypoxic-ischemic encephalopathy. We describe the relationship of quantifiable electroencephalogram (EEG) measures, obtained using a 2-channel digital bedside EEG monitor from term newborn infants with encephalopathy and/or seizures, to cerebral injury defined qualitatively by MRI. METHODS. Median values of minimum, mean, and maximum EEG amplitude were obtained from term-born encephalopathic infants during a 2-hour seizure-free period obtained within 72 hours of admission. Infants underwent MRI with images qualitatively scored for abnormalities of cortex, white matter, deep nuclear gray matter, and posterior limb of the internal capsule. Eighty-six infants had EEG measures related to qualitative MRI outcomes. RESULTS. The most common diagnosis was hypoxic ischemic encephalopathy (n = 40). For all infants there was a negative relationship between EEG amplitude measures and MRI abnormality scores assessed on a scale from 4 to 15, with a higher score indicating more abnormalities. This relationship was strongest for the minimum amplitude measures in both hemispheres; that is, for every unit increase in score there was a mean drop of 0.41 μv for the left cerebral hemisphere, with 35% of variance explained. This relationship persisted on sub-group analyses for infants with hypoxic-ischemic encephalopathy, infants with other diagnoses and infants monitored after the first 24 hours of life. Using an MRI abnormality score cutoff of 8 or worse for cerebral injury in infants with hypoxic-ischemic encephalopathy, a minimum amplitude of 4 μV showed a higher specificity (80%: left hemisphere), whereas a minimum amplitude of 6 μV showed a higher sensitivity (92%: left hemisphere). CONCLUSIONS. Bedside EEG measures in term-born encephalopathic infants are related to the severity of cerebral injury as defined by qualitative MRI. A minimum amplitude of <4 μV appears useful in predicting outcome.

Videolaryngoscopy to Teach Neonatal Intubation: A Randomized Trial

BACKGROUND: Neonatal endotracheal intubation is a necessary skill. However, success rates among junior doctors have fallen to <50%, largely owing to declining opportunities to intubate. Videolaryngoscopy allows instructor and trainee to share the view of the pharynx. We compared intubations guided by an instructor watching a videolaryngoscope screen with the traditional method where the instructor does not have this view. METHODS: A randomized, controlled trial at a tertiary neonatal center recruited newborns from February 2013 to May 2014. Eligible intubations were performed orally on infants without facial or airway anomalies, in the delivery room or neonatal intensive care, by doctors with <6 months’ tertiary neonatal experience. Intubations were randomized to having the videolaryngoscope screen visible to the instructor or covered (control). The primary outcome was first-attempt intubation success rate confirmed by colorimetric detection of expired carbon dioxide. RESULTS: Two hundred six first-attempt intubations were analyzed. Median (interquartile range) infant gestation was 29 (27 to 32) weeks, and weight was 1142 (816 to 1750) g. The success rate when the instructor was able to view the videolaryngoscope screen was 66% (69/104) compared with 41% (42/102) when the screen was covered (P < .001, OR 2.81, 95% CI 1.54 to 5.17). When premedication was used, the success rate in the intervention group was 72% (56/78) compared with 44% (35/79) in the control group (P < .001, OR 3.2, 95% CI 1.6 to 6.6). CONCLUSIONS: Intubation success rates of inexperienced neonatal trainees significantly improved when the instructor was able to share their view on a videolaryngoscope screen.

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 Womens 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.

Financial costs for parents with a baby in a neonatal nursery.

Aim:  To determine the additional financial cost to families of babies admitted to the nurseries of The Royal Womens Hospital, Melbourne, Australia.

Normative amplitude-integrated EEG measures in preterm infants.

Objective:Assessing qualitative patterns of amplitude-integrated electroencephalography (aEEG) maturation of preterm infants requires personnel with training in interpretation and an investment of time. Quantitative algorithms provide a method for rapidly and reproducibly assessing an aEEG recording independent of provider skill level. Although there are several qualitative and quantitative normative data sets in the literature, this study provides the broadest array of quantitative aEEG measures in a carefully selected and followed cohort of preterm infants with mild or no visible injury on term-equivalent magnetic resonance imaging (MRI) and subsequently normal neurodevelopment at 2 and 7 years of age.Study Design:A two-channel aEEG recording was obtained on days 4, 7, 14 and 28 of life for infants born ⩽30 weeks estimated gestational age. Measures of amplitude and continuity, spectral edge frequency, percentage of trace in interburst interval (IBI), IBI length and frequency counts of smooth delta waves, delta brushes and theta bursts were obtained. MRI was obtained at term-equivalent age and neurodevelopmental testing was conducted at 2 and 7 years of corrected age.Result:Correlations were found between increasing postmenstrual age (PMA) and decreasing maximum amplitude (R= −0.23, P=0.05), increasing minimum amplitude (R=0.46, P=0.002) and increasing spectral edge frequency (R=0.78, P=4.17 × 10−14). Negative correlations were noted between increasing PMA and counts of smooth delta waves (R= −0.39, P=0.001), delta brushes (R= −0.37, P=0.003) and theta bursts (R= −0.61, P=5.66 × 10−8). Increasing PMA was also associated with a decreased amount of time spent in the IBI (R= −0.38, P=0.001) and a shorter length of the maximum IBI (R= −0.27, P=0.03).Conclusion:This analysis supports a strong correlation between quantitatively determined aEEG measures and PMA, in a cohort of preterm infants with normal term-equivalent age neuroimaging and neurodevelopmental outcomes at 7 years of age, which is both predictable and reproducible. These ‘normative’ quantitative values support the pattern of maturation previously identified by qualitative analysis.