Objectives The adverse effects of hypotension in neonates are well discussed, yet there is a limited understanding of the trends and consequences of slow blood pressure variability (BPV).^1,2 We hypothesised there would be different profiles of BPV and blood pressure (BP) in the first 72 hrs of life.

Methods Infants born < 29 weeks were prospectively recruited, as part of a larger study looking at BP and EEG activity. Invasively measured BP data was sampled every 10 sec for the first 72 hrs of life. BP data from six 12 hr epochs was analysed (using MATLAB and SPSSv21) to determine relationships between BP, gestational age (GA) and inotropes during the first 72 hrs. BPV was quantified using the standard deviation and coefficient of variation of BP measurements from a 4-hour artefact-free section of data. Research ethics approval (12/LO/1553) and written parental consent were obtained.

Results In 18 subjects studied mean (range) gestation and birth weight were 25.4 (23–28) weeks and 756 (515–1070) grams respectively.

BP increased over the first 72 hrs (p

At 0–12 hrs babies receiving inotropes had significantly higher BPV (SD 4.9 vs 3.0, p = 0.003) but did not have significantly different BP (mean 30.7 vs 32.2, p = 0.48).

Conclusion Although BP increased in the first 72hrs of life, slow BPV was mainly affected by inotrope usage in the first 12hrs of life.

References

1. Miall-Allen VM, Whitelaw AGL. Effect of pancuronium and pethidine on heart rate and blood pressure in ventilated infants. Arch Dis Child. 1987;62:1179–80

2. Rennie JM. Cerebral blood flow velocity variability after cardiovascular support in premature babies. Arch Dis Child. 1989;64:897–901