Presented at the Neonatal Society 2015 Autumn Meeting.
Pereira SS1,2, Sinha AK1,2, Shah DK1,2, Morris J2, Wertheim D3, Kempley S1,2
1 Neonatal Unit, Royal London Hospital, Whitechapel, London E1 1BB, United Kingdom
2 Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom
3 Kingston University, Kingston upon Thames, Surrey KT1 2EE, United Kingdom
Background: Low blood pressure (BP) on the first day of life is associated with adverse neurodevelopmental outcome (1). The criteria for supporting low mean arterial BP (MABP) vary widely and have been identified as a priority for research (2). We hypothesise that different MABP thresholds for supporting BP in extremely preterm infants will result in different inotrope usage, levels of achieved BP, physiological and clinical parameters. We wished to compare levels which were higher or lower than the most commonly used intervention level in the UK.
Methods: This was a single centre RCT carried out in a tertiary NICU from Feb 2013 to June 2015. Infants <29 weeks gestation were recruited in the first 12 hours of life. Infants were randomised to one of three study arms:
1.Active: MABP was supported if it fell below 30 mmHg for > 15 min.
2.Moderate: MABP was supported if it fell below the infants gestational age in mmHg for > 15 min.
3.Permissive: Support given for evidence of impaired perfusion or if MABP fell below 19 mmHg for > 15 min. Clinical outcome parameters and inotrope use were recorded. Carotid blood flow and cardiac output were measured using Doppler ultrasound on day 1 & 3 of life. aEEG and BP were continuously downloaded. Analysis used ANOVA & Chi-square tests for ordered levels and Fisher’s exact test for small numbers and non-ordered effects (SPSS v22). Research ethics approval (12/LO/1553) was granted and parental consent obtained.
Results: The mean (range) gestation and B.Wt of the study group were 25.8 (23.3-28.9) wks and 817 (470-1470) grams.
There were no significant differences between groups in nurse-recorded MABP, or physiological characteristics. Clinical outcomes such as invasive ventilation, serum potassium and creatinine, BPD, PDA treatment (medical and surgical), NEC treatment (medical and surgical), Non-NEC perforation, ROP and days of BAPM level care were not significantly different between the three arms of the study.
Conclusion: This pilot study has shown that BP intervention threshold affects invasive BP and inotrope usage. The design was feasible and no major safety issues were identified. Results suggested a lower incidence of intraventricular haemorrhage or parenchymal brain lesions in the Active arm, which should be explored in larger trials.
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1. Faust K et al, ADC F&N. 2015
2. Short BL et al, Pediatrics. 2006