RESUMO
Background: There remains uncertainty about the definition of normal blood pressure (BP), and when to initiate treatment for hypotension for extremely preterm infants. To determine the short-term outcomes of extremely preterm infants managed by active compared with permissive BP support regimens during the first 72 hours of life. Method: This is a retrospective medical records review of 23 +0-28 +6 weeks' gestational age (GA) infants admitted to neonatal units (NNU) with active BP support (aimed to maintain mean arterial BP (MABP) >30 mmHg irrespective of the GA) and permissive BP support (used medication only when babies developed signs of hypotension) regimens. Babies admitted after 12 hours of age, or whose BP data were not available were excluded. Results: There were 764 infants admitted to the participating hospitals; 671 (88%) were included in the analysis (263 active BP support and 408 permissive BP support). The mean gestational age, birth weight, admission temperature, clinical risk index for babies (CRIB) score and first haemoglobin of infants were comparable between the groups. Active BP support group infants had consistently higher MABP and systolic BP throughout the first 72 hours of life (p<0.01). In the active group compared to the permissive group 56 (21.3%) vs 104 (25.5%) babies died, and 21 (8%) vs 51 (12.5%) developed >grade 2 intra ventricular haemorrhage (IVH). Death before discharge (adjusted OR 1.38 (0.88 - 2.16)) or IVH (1.38 (0.96 - 1.98)) was similar between the two groups. Necrotising enterocolitis (NEC) ≥stage 2 was significantly higher in permissive BP support group infants (1.65 (1.07 - 2.50)). Conclusions: There was no difference in mortality or IVH between the two BP management approaches. Active BP support may reduce NEC. This should be investigated prospectively in large multicentre randomised studies.
THE PROBLEM: Doctors are still not clear what the normal blood pressure (BP) is for premature babies during the first three days of life. Furthermore, it is unclear when to start treatment for low BP in preterm babies born at or before 28 weeks of gestation. What we did: We compared clinical outcomes of a group of preterm babies who were treated with medication to maintain BP above 30mmHg ('active BP treatment' group) to a group of babies who were treated when they developed signs of low BP ('permissive BP treatment' group) from two large Neonatal Intensive Care Units (NICU) in London, UK. How we tested it: Preterm babies born between 23 and 28 weeks gestation were studied. Babies admitted after 12 hours of age, or whose BP information was not available were excluded. BP measurements for the first 72 hours of life, and clinical outcome details of babies from NICU admission to discharge home were collected from medical records. What we found: There was no difference in the level of prematurity, birth weight, and severity of illness score at admission between the active BP treatment and permissive BP treatment group babies. Active BP treatment group babies had a higher BP throughout the first 72 hours of life. There was no important difference in the number of babies who died or developed moderate grade brain haemorrhage between the active BP treatment group compared to the permissive BP treatment group. A significantly lower number of the active BP treatment group babies developed necrotising enterocolitis (NEC, inflammation of gut). CONCLUSIONS: There was no difference in death or brain haemorrhage in babies between the two BP treatment methods. Active BP treatment during the first 72 hours of life may reduce NEC in preterm babies. This should be studied in large multicentre clinical studies.
