In this retrospective cohort study, we utilize the Utstein reporting guidelines (5) to determine the outcomes and factors associated with survival at 24 hours after in-hospital cardiac arrest among acutely ill pediatric patients presenting to an urban emergency department of a tertiary referral hospital in Tanzania. In this study we found one in two patients attained sustained ROSC, and 3 out of 10 patients were alive at 24 hours following IHCA, a higher survival rate than that observed in other studies in sub-Saharan countries (4, 8). These difference in the survivals between this study and other studies in sub-Saharan countries may be because this study was conducted in a facility with advanced pediatric life support training, and with more resuscitation resources. We found a very low survival to hospital discharge at only 5% is a low rate than most reported studies in medium and high-income countries(9–13), we believe this finding is contributed by inadequate post resuscitation care after the initial survival, also delayed presentation, and advanced pathophysiology of underlying diseases at presentation.
In our study, half of the patients (50%) were infants. This observation is similar to the meta-analysis done by Young KD et al where younger age group with respiratory conditions contributed to higher percentage of cardiac arrest (3). This high proportion of infants who had IHCA may be attributable to the high prevalence of respiratory infections in this age group and their tendency to decompensate rapidly. However, age, and sex were not associated with survival at 24 hours in the multivariate analysis
Interestingly, the survival was higher among those patients who had cardiac arrest event during day or evening, had duration of CPR ≤ 20 minutes, those who received ≤ 2 doses of epinephrine, among those with identified reversible cause of cardiac arrest, and patients who had mechanical ventilated after CPR.
Patients who had IHCA during the daytime and evening hours were more likely to survive at 24 hours compared to those who had cardiac arrest during nighttime. The lower survival rate among patients who had cardiac arrests at nighttime are consistent with other studies(9, 11, 14). Lower survival rate at nighttime is an important, yet underrecognized concern. In our hospital, there is only one attending physician available during nighttime, and the resuscitation rooms are shared by residents and medical officers. In addition, there are smaller number of nursing officers allocated during nighttime compared to day/evening time, perhaps influencing the recognition and response to deteriorating patients and those experiencing cardiac arrest. In addition, medical errors are more common (15), and there is reduced ability in performing psychomotor skills at night (16).
In this study, analysis of the resuscitation parameters showed that, patients with shorter CPR duration (≤ 20 minutes), and those who required a smaller number of epinephrine doses (≤ 2 doses) were more likely to survival at 24 hours, coinciding with the findings reported in other studies (1, 10, 17). The goal of effective CPR is to optimize coronary and cerebral perfusion pressure and blood flow to critical organs during the low flow phase of CA. During this phase, the only source of coronary and cerebral perfusion comes from the blood pressure generated by good chest compressions. Longer duration of arrest results in a longer period of low cardiac output with increased potential for organ injury. It is unlikely that patients with prolonged duration of CPR and requirement of a greater number of epinephrine doses had effective mechanical activity of the heart. These findings highlight the importance of implementing early resuscitation measures to prevent further deterioration of the heart mechanical function.
Patients who had identifiable reversible causes of CA were more likely to survive at 24 hours than those who had no reversible causes recognised. There is a paucity of data reporting this association in pediatric patients with IHCA who underwent CPR. In this study, 78 (57.5%) of patient who underwent CPR had their reversible causes of CA identified. To what extent the recognition of cause of cardiac arrest influences survival has not been thoroughly investigated in pediatric population. In a study conducted in adults, patients suffering an IHCA showed a substantial survival benefit if the causes of arrest were recognized by the emergency team. This finding supports the AHA recommendation that cardiac arrest in children may be associated with a reversible condition, rapid recognition, immediate high-quality CPR, and correction of contributing factors and potentially reversible causes offer the best chance for a successful resuscitation (7).
Patients who required mechanical ventilation after ROSC had better survival at 24 hours than those who were not mechanically ventilated. This finding is in keeping with a study conducted in Egypt in a similar population of patients (18). Post-cardiac arrest derangements in partial pressure of carbon dioxide (PaCO2) are common. Alterations in PaCO2 could affect outcome by exacerbating the ischemic insult through hypocarbia induced cerebral vasoconstriction or through hypercarbia- induced cerebral vasodilation and edema, lungs may also be damaged from trauma due to chest compressions, aspiration of blood/gastric content or development of pneumonia. Data extrapolated from pediatric critical care suggest that during post-cardiac arrest care, use of mechanical ventilation lung protective strategies, including low inspiratory volume and positive end-expiratory pressure, are warranted to minimize lung injury and hemodynamic compromise (19). Assessment of patient immediate post-cardiac arrest to further establish the adequacy of oxygenation and ventilation is necessary to provide assisted ventilation as needed.
Study limitations
This was a single site retrospective cohort study with a small sample size that was carried out in a tertiary hospital in Tanzania, where the population and resuscitation measures may not be representative of the whole country which limits the generalizability of our findings.
We only analyzed factors in the first 24 hours after ROSC, which may be the most important but not the only ones. Other factors that might affect the survival at discharge but may appear in the following days, such as nosocomial infections or multiple organ failure, and post-cardiac arrest care were not studied.