Richter, A.E. (Anne) (2015) The effect of maternal antihypertensive drugs on cerebral, renal and intestinal tissue oxygenextraction in premature neonates. thesis, Medicine.
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Abstract
Background: Prematurity is associated with hemodynamic instability and organ vulnerability. Mothers from prematurely born infants often received antihypertensive drugs due to preeclampsia or placental insufficiency (labetalol), for tocolysis (nifedipine), or as neuroprotective agents (magnesium sulfate, MgSO4). These drugs are known to cross the placenta, persist in the neonatal circulation for a few days after birth and possibly cause adverse hemodynamic effects in the fetus and neonate. Objective: To assess whether maternal antihypertensive drugs have a significant, possibly negative effect on neonatal regional tissue oxygen extraction. Methods: We included 80 premature newborns, whose cerebral, renal and abdominal oxygen saturations were continuously monitored during the first 5 postnatal days by the use of near-infrared spectroscopy (NIRS). Additionally measured peripheral oxygen saturations were used to derive mean cerebral, renal and splanchnic/mesenteric fractional tissue oxygen extractions (cFTOE, rFTOE, and sFTOE, respectively). Newborns were divided into four groups: exposure to labetalol +/- MgSO4, exposure to nifedipine +/- MgSO4, exposure to MgSO4 only, and no exposure to maternal antihypertensive drugs (control group). With the use of simple and multiple linear regressions we determined the effect of various maternal antihypertensive drugs on cFTOE and rFTOE. Their relationship with sFTOE was explored using Krsukal-Wallis and Mann-Whitney U tests. Results: Corrected for confounders, labetalol +/- MgSO4, nifedipine +/- MgSO4 and MgSO4 alone did all have a significant lowering effect on cFTOE on day 2 after birth when compared to neonates unexposed to maternal antihypertensive drugs (p = 0.012, 0.033, and 0.037, respectively). Labetalol +/- MgSO4 was also associated with significantly lower cFTOE values on day 4 (p = 0.028). sFTOE, in contrast, was significantly increased by labetalol +/- MgSO4 on day 1 and 2 (p = 0.040 and 0.007, respectively). rFTOE was not influenced by exposure to maternal antihypertensive drugs (p > 0.1). Conclusion: Although maternal antihypertensive drugs were significantly associated with a decrease in cFTOE, the pathophysiological cause remains uncertain. An increase in cerebral aqperfusion and oxygen supply may have caused the decrease in regional oxygen extraction associated with labetalol or nifedipine. This could be attributed to pharmacologic drug action or rather to a brain-sparing effect associated with maternal preeclampsia and placental insufficiency. Especially in newborns exposed to labetalol brain-sparing may explain the decrease in cFTOE with the concomitant increase in sFTOE. Decreased cFTOE associated with MgSO4 may be explained by neurological depression and decreased oxygen qmight be related to renal autoregulation. In any case, careful monitoring of newborns exposed to maternal antihypertensive drugs is recommended, although the clinical significance of our results is yet to be explored.
Item Type: | Thesis (Thesis) |
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Supervisor name: | Faculty supervisor: and Kooi, Elisabeth M. W. MD and University Medical Center Groningen, Department of Neonatolo |
Faculty: | Medical Sciences |
Date Deposited: | 25 Jun 2020 11:00 |
Last Modified: | 25 Jun 2020 11:00 |
URI: | https://umcg.studenttheses.ub.rug.nl/id/eprint/2029 |
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