Discussion
In this observational study, a high proportion of resuscitated neonates had SpO2 values below AHA target in the first 10 min after birth, while heart rate remained above 100 bpm for the most part of the measurements.
The strengths of the present study include (1) data collection from review of video recordings allowing detailed monitoring of observed parameters, signal quality and hence enhanced reliability of data20 21; (2) the assessment of SpO2 and heart rate in a low-resource setting where PPV is performed in room air without the SpO2 monitoring.
Few studies have observed SpO2 during neonatal resuscitation. In a study by Saugstad et al, median SpO2 in neonates resuscitated with room air was 90% (5th–95th percentile 66–95, n=100) at 5 min and 90% (83–96, n=110) at 10 min, median Apgar score 4, 7 and 8 at 1, 5 and 10 min, respectively.13 Our corresponding figures were 67% (IQR 49–88) and 93% (80-97). Reasons for lower saturation at 5 min could be quality of resuscitation, observational method or severity of the asphyxia. Three-quarters of neonates in this study had Apgar score <7 at 5 min, associated with increased risk of mortality and morbidity.22–24 In Nepal, mean SpO2 levels in an early cord clamping group who received PPV (n=45) were 76.1% (SD 3.9) at 5 min and 85.1% (SD 2.8) at 10 min. SpO2 at 10 min was somewhat lower than in our study and results were also below the AHA targets.15 In both studies, SpO2 data were collected by direct observation and not by video review. SpO2 in neonates at high altitude (>4000 m above sea level) has been shown to be lower compared with measurements at sea level.25 Another study at similar altitude as Kampala observed comparable SpO2 at birth with the reference study at sea level by Dawson et al (median 69% vs 66% at 1 min), and we assume the altitude had a minor impact on our results.6 26
The high SpO2 dispersion reflects the variability of illness in resuscitated neonates. In our study, 43% of the neonates received oxygen after PPV (upon midwives’ assessment of breathing difficulties or cyanosis). This probably increased median SpO2, especially from 5 min after birth. Still, large proportions of patients (59% at 5 min, 32% at 10 min) had an SpO2 below AHA target. When only neonates before and during PPV were analysed, the proportion was even more prominent (83% at 5 min, 67% at 10 min) (table 3). Yet, most neonates had heart rate above 100 bpm, which is considered a sign of adequate ventilation (figure 2).3 4 This suggests that adequate PPV alone is not sufficient to achieve SpO2 in the recommended range. Though, since no respiratory function monitoring was used, conclusions about adequacy of PPV is not possible to make. This study observed a large portion of neonates with either meconium-stained, or foul-smelling amniotic fluid, or both indicating meconium aspiration. This could theoretically explain the low SpO2 in this sample, but a post hoc analysis surprisingly showed higher SpO2 in the group with meconium-stained amniotic fluid. A finding hard to interpret, but high rate of missing data in the meconium group and the small sample size are possible explanations. Persistent hypoxia in asphyxiated neonates may exacerbate pulmonary hypertension and have short-term and long-term consequences of hypoxic-ischaemic encephalopathy.27 Oxygen is not included in the HBB algorithm, since it is scarce and difficult to administer in blended form in low-income contexts,10 28 but the availability of oxygen in sub-Saharan African hospitals is increasing.29 30 A neonatal resuscitation algorithm for low-resource and middle-resource settings that includes oxygen has been proposed.31 The present study might support its use. Nevertheless, preventing dangerous hyperoxia is also recommended3 4 7; of note, 33% of neonates receiving supplemental oxygen after PPV had SpO2 levels above target range (>95%) at 10 min. These findings suggest that SpO2 measurement would be considered also in low-resource settings because the agreement between the assessment of infant colour and SpO2 is limited.32
The questions regarding supplemental oxygen still remain: oxygen or not, when and how much? Our results raise the question if these neonates would benefit from supplemental O2 during PPV. However, transferring a practice from one context to another may have detrimental effects.33 Caution must be taken not to implement an advanced resuscitation algorithm before the basic skills of good quality PPV have been mastered. Safe and accessible devices to blend and titrate oxygen need to be available as well as SpO2 monitoring to avoid both hypoxia and hyperoxia. Optimal saturation and oxygenation for neonates in need of PPV needs to be further investigated.7 8
This study has some limitations. It was an exploratory investigation with a limited number of participants which prevented calculations of CI and hence results can be difficult to generalise. Neonates were selected by convenience sampling based on the research physician’s availability, with risk for selection bias. However, baseline characteristics were in broad agreement with the NeoSupra Trial (table 1).17 Of note, the observed high rate of CS (84%) was partly due to convenience sampling but also due to lack of oximeter visibility on video recordings from the labour ward resuscitation table, where vaginal deliveries were performed. This was one of the main reasons for exclusion of neonates initially selected for analysis. Dawson et al reported that healthy babies born by CS are known to have lower SpO2 compared with those by vaginal delivery.6 It is difficult to assess if the high rate of CS affected the results in these severely asphyxiated neonates. This observational study suffered from missing SpO2 and heart rate data, particularly immediately after birth. This seems to be a random data loss that would not affect the results but implies an uncertainty to the data, especially at the initial time intervals. Median time to start of ventilation (123 s) in this study was markedly above the aimed for ‘golden minute’ (first minute of life), indicating difficulties in compliance with the HBB algorithm, mostly due to prolonged stimulation and suctioning. The delay in ventilation is a possible explanation of the low SpO2 in our study and it would be interesting to see if SpO2 improves with earlier start of ventilation. Time to PPV from birth in an earlier cohort at the same hospital was 137 s (n=99) and 92 s (n=48) after CS, indicating the problem is recurring.34 This is however not an issue unique to our study site. In a video observation study of 76 neonates from a hospital in Tanzania (where numerous HBB studies have been undertaken) that included rigorous HBB training, median time from birth to first ventilation was 108 s and the total duration of stimulation and suctioning before first ventilation was 45 s.35 A study from Mozambique found similar delays in ventilation after training.36 These examples highlight the difficulty in reaching the HBB target in this setting and we believe our results might reflect the situation in other busy hospitals in sub-Saharan Africa.