102 Use of blood pressure trends to predict severity of hypotensive episodes in neonates

Abstract Background Hypotension leading to circulatory insufficiency is a serious morbidity in neonates admitted to Neonatal Intensive Care Unit (NICU). Early recognition, and timely and appropriate treatment are essential to prevent adverse consequences. However, currently there are no early tools to predict episode severity to allow triaging of patients to higher level of care or intervention. Objectives This study aimed to look at trends in vital signs 6 hours prior to use of vasoactive agent and analyzed the relationship between the early trends and episode severity and outcomes. Design/Methods This was a retrospective cohort study at a tertiary care NICU in Southwestern Ontario that included all neonates who needed inotropic support between Jan 1, 2018, to Dec 31, 2022. Data regarding physiological parameters in the 6 hours prior to inotropic agent start were collected. Details of the episodes including number of vasoactive agents, doses, vasoactive inotropic score (VIS) and outcomes such as mortality were collected. The relationship between changes in vital signs (systolic blood pressure [SBP], diastolic blood pressure [DBP], mean blood pressure [MBP], heart rate and oxygen saturation index [OSI]) and episode severity (VIS) and mortality were examined. Repeated measures analysis of variance models was used to examine trends over time between age groups, and logistic regression models were used to examine predictors of dichotomous outcomes. Results 154 neonates were included in the study. 50.6% of cohort were <28 weeks,14.9% were 28-34 weeks and 34.4% were >34 weeks. Baseline characteristics and underlying etiology for hypotension are summarized in Table 1. On analysis of blood pressure values 6 hours prior to initiation of vasoactive agents (6-0hrs), we detected a significant declining trend over time in SBP, DBP and MBP for all neonates (Figure 1). The changes in heart rate and oxygen requirement were not significant in that 6-hour window. The logistic regression analysis showed that, for every 1-unit drop in SBP 6-0hrs, DBP 6-0hrs and MBP 6-0hrs, VIS increased by 0.30 (95%CI=0.50, 0.10), p=0.003; 0.32 (95%CI=0.56, 0.07), p=0.012; and 0.26 (95%CI=0.51, 0.01), p=0.044 respectively. Similar findings were recorded during the period of 3hours prior to initiation of vasoactive agents (3-0hrs) . Assessment of indices of oxygenation demonstrated that for every 1-unit increase in OSI 3-0hrs, VIS increased by 1.07 (95%CI=0.34, 1.80), p=0.005. Vital sign trends did not show a relationship to mortality as shown in Table 2. Conclusion This study shows that blood pressure drops significantly in the 6 hours prior to actual initiation of vasoactive medications. The rate of drop could successfully predict episode severity. Integrating the rate of hourly change in BP within routine vital monitoring algorithms could be clinically useful in managing vulnerable neonates.