<p>Pulmonary function and systolic blood pressure in very low birth weight infants at 34–36 weeks of corrected age</p>

Abstract

Purpose: Preterm infants are at increased risk of systemic hypertension compared to term infants. Bronchopulmonary dysplasia (BPD) has been shown to be associated with hypertension in preterm infants albeit with no causation reported. BPD is characterized by abnormal pulmonary function tests (PFTs), specifically elevated passive respiratory resistance (Rrs), decreased passive respiratory compliance (Crs), and decreased functional residual capacity (FRC). There have been no studies comparing PFTs in very low birth weight (VLBW) infants with and without hypertension. We hypothesized that stable VLBW infants with hypertension will have altered PFTs. Patients and methods: Retrospective cohort study of infants <1500 g at birth (VLBW) who had PFTs performed near 34-36 weeks of corrected gestational age (CGA). We excluded infants with congenital anomalies, known hypertensive disorders or those at risk of medication-induced hypertension. Data obtained included PFT parameters (Rrs, Crs, FRC) and mean systolic blood pressure (SBP). Results: Fifty-nine VLBW infants were identified for analysis, 14 with and 45 without hypertension. Hypertensive and normotensive patients were similar in terms of mean gestational age (26.6 vs 27.4 weeks), mean CGA at PFTs (36.1 vs 34.6 weeks) and proportion of BPD (36% vs 36%). The Rrs was significantly higher in hypertensive versus normotensive patients [median Rrs of 0.080 (0.069, 0.090) versus 0.066 (0.054, 0.083) cmH 2 O/mL/s; p=0.04]. There was no difference in systolic blood pressure in the infants with and without BPD. Conclusion: In this cohort of contemporary VLBW infants, those with hypertension had increased Rrs. This finding warrants a prospective study with a larger sample size and longterm follow-up. Plain language summaryPrior work has linked bronchopulmonary dysplasia (a chronic lung disease that is relatively common in the most premature of neonates) to systemic hypertension; however, this link has not been fully elucidated. To add to the limited fund of knowledge surrounding this association, our group compared objective pulmonary function test parameters of premature neonates with and those without systemic hypertension. The findings of our work demonstrate that there is commonly an increase in the airway resistance in those with systemic hypertension compared to those without. We speculate that since adequate vascular development within the lungs and kidneys promotes growth, there could be a common developmental issue within the lung and kidney causing the altered lung mechanics and elevated blood pressure, but this will require further study.

Blood pressure in preterm infants with bronchopulmonary dysplasia in the first three months of life

“…The length of the investigated period and the high number of blood pressure measurements make our study valuable in this eld. Several clinical studies have con rmed the increased risk of hypertension in BPD patients [5,[8][9][10][11][12][13]24], while other studies have not found a risk of high blood pressure in premature infants with BPD [6,7]. In addition to the different diagnostic criteria used for BPD and hypertension, this difference could be due to the various and short periods when the blood measurements were taken.…”

“…BPD and the consequent hypertension can signi cantly affect premature infants' short-and long-term life outcomes. Despite several studies on this topic, there are unanswered questions on the development of blood pressure in premature infants with BPD [5][6][7][8][9][10][11][12][13]. Our study aims to investigate the blood pressure changes of premature BPD patients during the rst three months of life.…”

Blood pressure in preterm infants with bronchopulmonary dysplasia in the first three months of life

“…BPD and consequent hypertension can significantly affect premature infants' short-and long-term life outcomes. Despite several studies on this topic, there are unanswered questions regarding the blood pressure changes in premature infants with BPD [3][4][5][6][7][8][11][12][13][14]. Among these questions, the most important ones are the onset and frequency of hypertensive periods in BPD patients.…”