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The effect of phototherapy on renal blood flow velocity in preterm infants
M J Benders1, F van Bel, M van de Bor
1Department of Pediatrics, University Hospitals Leiden, The Netherlands. M._vandeBor@cksbb.azn.nl
Insights
Phototherapy for nonhemolytic hyperbilirubinemia in preterm infants significantly reduces renal blood flow velocity and increases renal vascular resistance. These changes may not fully reverse in critically ill infants, and phototherapy can reopen the ductus arteriosus.
Area of Science:
- Neonatal Medicine
- Pediatric Nephrology
- Cardiovascular Physiology
Background:
- Nonhemolytic hyperbilirubinemia is common in preterm infants.
- Phototherapy is a standard treatment for hyperbilirubinemia.
- Potential effects of phototherapy on renal hemodynamics in neonates are not fully understood.
Purpose of the Study:
- To investigate the impact of phototherapy on renal blood flow velocity (RBFV) and relative renal vascular resistance (RVR) in preterm infants.
- To assess the reversibility of these hemodynamic changes after phototherapy discontinuation.
- To evaluate the incidence of ductus arteriosus reopening during phototherapy.
Main Methods:
- Utilized two-dimensional and pulsed Doppler ultrasound to measure mean RBFV.
- Calculated RVR before, during, and after phototherapy.
- Studied 30 preterm infants (gestational age <= 32 weeks) treated for at least 12 hours.
- Categorized infants into 'healthy' (nonventilated) and 'unhealthy' (ventilated) groups.
Main Results:
- Phototherapy initiation led to a significant decrease in RBFV and a significant increase in RVR.
- In healthy infants, RBFV and RVR returned to baseline post-phototherapy.
- In unhealthy infants, RBFV and RVR did not normalize after phototherapy.
- The ductus arteriosus reopened in over 50% of infants during treatment.
Conclusions:
- Phototherapy significantly alters renal hemodynamics in preterm infants.
- Recovery of renal hemodynamics may be impaired in ventilated, critically ill neonates.
- Phototherapy is associated with ductus arteriosus reopening in a substantial proportion of preterm infants.
Abstract:
Mean renal blood flow velocity (RBFV) was studied with two-dimensional/ pulsed Doppler ultrasound and relative renal vascular resistance (RVR) was calculated before, during, and after phototherapy treatment in 30 preterm infants (gestational age < or = 32 weeks) who were treated for a minimum of 12 h with phototherapy for nonhemolytic hyperbilirubinemia. RBFV decreased, whereas RVR increased significantly after the initiation of phototherapy. In 'healthy' (nonventilated) infants RBFV and RVR returned to baseline values after discontinuation of phototherapy. Whereas in 'unhealthy' (ventilated) infants, RBFV and RVR did not return to baseline values after discontinuation of phototherapy. In 16 infants (> 50% of the cases) the ductus arteriosus reopened during phototherapy.