Systolic blood pressure in babies of less than 32 weeks gestation in the first year of life

Abstract

Aim-To define the normal range of systolic blood pressure in a non-selective population based sample of babies of low gestation throughout early infancy. Methods-Daily measurements of systolic blood pressure were made in all the babies of less than 32 weeks gestation born in the North of England in 1990 and 1991 during the first 10 days of life. Additional measurements were obtained from 135 of these babies throughout the first year of life. Systolic pressure was measured by sensing arterial flow with a Doppler ultrasound probe. It was assumed that blood pressure had never been pathologically abnormal in the neonatal period if the child was alive and free from severe disability two years later. Data of adequate quality were available from 398 such children. Additional data were collected, for comparative purposes, from 123 babies of 32, 36, or 40 weeks of gestation. Results-Systolic pressure correlated with weight and gestation at birth, and rose progressively during the first 10 days of life. The coeYcient of variation did not vary with gestational or postnatal age (mean value 17%), the relation with gestation being closer than with birthweight. Systolic pressure rose 20% during the first 10 days from an initial mean of 42 mm Hg in babies of 24 weeks gestation, and by 42% from an initial mean of 48 mm Hg in babies of 31 weeks gestation. These findings were not altered by the exclusion of data from 14 babies who had inotropic support during this time. Simultaneous measurements in three centres using an oscillometric technique revealed that this technique tended to overestimate systolic pressure when this was below average. Systolic pressure finally stabilised at a mean of 92 (95% CI 72-112) mm Hg at a postconceptional age of 44-48 weeks irrespective of gestation at birth. Conclusion-Systolic blood pressure 4-24 hours after birth was less than gestational age (in weeks) in only 3% of non-disabled long term survivors. Systolic pressure rose with increasing gestation and increasing postnatal age, but stabilised some six weeks after term, regardless of gestation at birth. (Arch Dis Child Fetal Neonatal Ed 1999;80:F38-F42)

Blood Pressure Variability and Baroreflex Sensitivity in Premature Newborns—An Effect of Postconceptional and Gestational Age

“…Several previous studies demonstrated that regardless of gestation week at birth where marked difference in BP values are observed, BP values become similar at the postconceptional age of 42 – 44 weeks ( 31 , 32 ). In agreement with previous data, the newborns from our study born more prematurely, despite having a longer postnatal age (almost 24 vs. 6 days) at the time of measurement, have not yet been able to reach BP and HR values of babies with higher gestational and lower postnatal age at the 35th postconceptional week.…”

Critical Serum Creatinine Values in Very Preterm Newborns

“…Here, the 90 th percentile of HSCr values (from postnatal days 3-30) of children with an optimal two-year outcome were used to determine the serum creatinine critical values, which were then validated in a second group with the same neonatal characteristics. Thus, limits arising from intrinsic characteristics of the deceased infants within our cohort were overcome through internal validation of our critical values [ 27 ]. Importantly, risk factors for HSCr above the critical values were similar to risk factors for renal failure described in the literature [ 1 , 4 , 10 ].…”

“…Definition of critical values in the training group: To determine our critical values, we considered the highest serum creatinine values of children from the training group showing an optimal neurodevelopmental outcome at two years of corrected age. The 90 th percentile of HSCr levels from these children with an optimal neurodevelopmental outcome were then used to define critical values for each GA subgroup, as previously reported for other parameters like blood pressure [ 27 ].…”

Hyperbilirubinemia and Neurodevelopmental Outcome of Very Low Birthweight Infants: Results from the LIFT Cohort

“…Because of physiological particulars and many comorbidity factors [3] – [4] , it is difficult to define guidelines for starting phototherapy in VLBW infants. One validated method consists of analyzing data in infants with optimal outcome and then defining norms [22] . To determine the most adapted SBL for starting phototherapy in infants under 1001 g, we compared the 95 th percentile of SBLs in infants with optimal neurological outcome in relation to birthweight.…”