In this obstetric setting, the average decision-to-delivery interval was 5.5 hours, with only 2% of babies delivered within an hour of decision-making. Women with certain indications were delivered more quickly once the decision for emergency cesarean section was made. Fetal distress, malpresentation, antepartum haemorrhage, and previous cesarean section (both with and without concern regarding impending uterine rupture) were prioritised over other indications. Whilst there was no association between the length of the decision-to-delivery interval and adverse perinatal outcomes, both the interval and risk of perinatal mortality showed significant diurnal variation. The time of decision-making was better correlated with the risk of adverse perinatal outcome that the time of delivery.
Accounting for the time taken to clean and restock the theatres between cases, we observed a remarkable continuous rate of emergency surgery in this LM-HDI setting. The average decision-to-delivery interval was significantly longer than targets adopted in well-resourced obstetric settings10 as well as the average interval reported in other low resource contexts globally13,23. However inconsistent categorisation of cases as ‘emergencies’24 and different obstetric populations complicate international comparisons.
There was significant diurnal variation in decision-to-delivery interval and risk of perinatal death, which may reflect the fluctuating availability of senior clinicians during a 24-hour period. As in many obstetric settings globally, the most experienced obstetricians at Mulago Hospital are available for ward rounds and decision-making during the day, however, not overnight. In line with this, the times of shortest interval occurred during normal working hours (12:00-20:00). The period with fewest decisions for emergency cesarean section were made (22:00-02:00) corresponded to the times of highest perinatal mortality, whilst the period when the rate of decision-making was increasing most rapidly (09:00-13:00) was associated with the lowest risk.
Reducing the average decision-to-delivery interval by 5 hours in keeping with the 30-minute targets set elsewhere9,10 is unlikely to be feasible in our already under-resourced study setting. Moreover, existing guidelines are not well-evidenced11 with little direct evidence of benefit even in well-resourced obstetric setting. We did not find evidence of a direct relationship between longer interval and adverse perinatal outcomes, therefore it is unlikely to be of benefit to focus scarce resources towards dramatically reducing absolute time to delivery. Rather, our data support the idea that clear, timely, and well-supported clinical decision-making may have more influence on perinatal outcomes. Normal working hours also correspond to the highest availability of non-medical services such as technicians, porters and laboratory clinicians. This may therefore also be an independent aspect for the hospital to consider when developing service design to improve perinatal outcomes. Whilst continuously performing emergency cesarean section has significant demands on resource utilisation and may be a non-modifiable limiting factor, it is rational to believe that clinical delays to treatment are modifiable even within resource constraints. A previous study, for example, demonstrated that the average time to complete obstetric triage reduced from 192 to 38 minutes when a midwife was allocated to this specific task 22.
The high volume of deliveries and baseline incidence of adverse events at Mulago Hospital meant that, although temporally short, our study was sufficiently powered for the crucial outcomes of perinatal and neonatal mortality. The high baseline incidence of adverse outcomes in our study (~5% maternal adverse outcomes and ~10% perinatal mortality) are in keeping with previously reported outcomes from the study centre 25,26. Furthermore, since such a high volume of deliveries can complicate detailed medical record-keeping, our strategy of bespoke contemporaneous data collection by a dedicated researcher present in the institution increases our confidence in the accuracy of the timings presented. The study is also underpinned by a powerful and sophisticated statistical modelling strategy, in which non-parametric dynamic additive models were used to determine the risks of adverse perinatal outcomes relative to baseline risk, without making assumptions about the risk / time relationship.
A limitation of the current study is that our results relate only to delay in delivery after the decision for emergency cesarean is made. Previous analysis from the study setting has found that the average triage time is longer for mothers who present overnight22. Delays besides the decision-to-delivery interval may therefore vary in a predictable diurnal cycle. We were also unable to explicitly model the influence of the experience of available obstetricians throughout the day. Whilst the periods during which the least experienced obstetricians are alone in the hospital correlate with the longest decision-to-delivery intervals and highest risk of perinatal mortality, we could not demonstrate a causal association here. A further limitation is the absence of a routinely applied categorisation of urgency for non-elective caesareans in the study context. Adoption of such a system could help to identify and prioritise higher risk cases, providing further scope for reducing perinatal mortality. While our study utilises a large cohort, there was insufficient power to analysis the relationship between decision-to-delivery interval and perinatal outcome separately for each indication for caesarean section. It might be expected that for some indications, particularly those in which delivery is very urgent such as cord prolapse, that a more direct relationship might exist. For other indications, such as fetal malpresentation, the findings of sub-group analyses would be likely consistent with the full cohort data.
In this context, where many mothers present to hospital already in obstructed labour27, a direction of future study would be to investigate delays in the total time to delivery besides the decision-to-delivery interval. Such delays may also vary diurnally, for example, due to traffic patterns in the surrounding urban area. Clinician experience can be associated with perinatal outcomes both indirectly, through increased decision-to-delivery interval and directly, through for example operative skill. Further analysis of the obstetricians available throughout the day is required to determine whether modifying the periods during which the those least experienced are alone in the hospital would result in reduced risk of perinatal mortality. Future analyses in this area should also include analysis of factors potentially contributing to adverse outcomes after the decision for emergency caesarean section has been made.