Cerebral hemodynamic change and intraventricular hemorrhage in very low birth weight infants with patent ductus arteriosus

Surgical closure of the patent ductus arteriosus and its effect on the cerebral tissue oxygenation

AIM

Surgical patent ductus arteriosus (PDA) ligation is considered after failure or contraindication of medical treatment. Till now ligation of the PDA has been associated with low morbidity and mortality although recently concerns have been raised about the possible association of ductal clipping and neurodevelopmental abnormalities later in life. By means of near-infrared spectroscopy (NIRS), we analysed the changes in the cerebral tissue oxygenation index (TOI) and fractional tissue oxygen extraction (FTOE) at the time of clipping as well as after clipping.

METHOD

Ten preterm infants with a symptomatic PDA who underwent surgical ligation were continuously monitored for heart rate (HR), mean arterial blood pressure (MABP), peripheral oxygen saturation (SaO(2)) and TOI from 1 h before up to 1 h after clipping. FTOE and haemoglobin difference (HbD) were calculated. Changes in parameters at 5 min after ligation represent the effect of the clipping itself whereas changes up to 1 h-post-clipping represent the post-clipping effect.

RESULTS

At the exact time of clipping, over the entire group, we found a significant increase in TOI of 2.9% (p = 0.037), in HbD of 12.5 micromol/l (p = 0.047) and in HR of 6.5 bpm (p = 0.012). FTOE significantly decreased by 0.02% (p = 0.013). One hour post-clipping, the cerebral and peripheral parameters were not significantly different from the control values before clipping.

CONCLUSION

The ductal clipping in se has no negative effect on the cerebral oxygenation.

End-diastolic block in cerebral circulation may predict intraventricular hemorrhage in hypotensive extremely-low-birth-weight infants

We investigated the association of intracranial arterial end-diastolic block with mean arterial pressure (MAP), patent ductus arteriosus (PDA) and intraventricular hemorrhage (IVH) in infants with birth weights <1000 g. End-diastolic block was diagnosed when end-diastolic flow was found to be absent from the Doppler waveforms in cerebral arteries by pulsed Doppler ultrasound examinations. Cranial ultrasonography and pulsed Doppler examination of anterior cerebral and basilar arteries were performed in 55 preterm infants (gestational age range 24-31 wk) one to four times during the first four days of life. Of these, 22 (40%) developed an end-diastolic block at least once (block group); in 33 no block was detected (control group). Echocardiography was performed and MAP recorded concomitantly. The block group infants had significantly lower mean MAPs than the controls and 59% of those had MAP of 30 mm Hg or lower. In the block group, IVH developed more often in infants with MAP <30 mm Hg (46%) than in infants with MAPs >30 mm Hg (0%). However, in the control group IVH developed equally frequently in infants with MAP < or =30 mm Hg (33%) and in infants with MAP >30 mm Hg (30%). PDA was a significant risk factor for IVH. An end-diastolic block in the cerebral circulation, together with a MAP of < or =30 mm Hg or less and the presence of PDA during the first four days of life, might be associated with IVH in extremely-low-birth-weight infants.

Near-infrared spectroscopy as a screening tool for patent ductus arteriosus in extremely low birth weight infants

BACKGROUND

Patent ductus arteriosus (PDA) is frequent and potentially pathologic in preterm infants. A simple bedside tool to screen for ductal patency would assist in the care of extremely low birth weight (ELBW) infants.

OBJECTIVE

To investigate the utility of near-infrared spectroscopy (NIRS) in identifying ELBW infants who would benefit from early echocardiography.

METHODS

Tissue oxygen saturation (S(t)O(2)) was measured by NIRS in the lungs, brain, skeletal muscle and kidney of 20 ELBW infants. Comparisons were made between the S(t)O(2) in these organs and the need for intervention for a PDA. All studies were performed within the first 4 days of life. Similar measurements were performed following treatment with indomethacin in nine of the patients.

RESULTS

The S(t)O(2) of skeletal muscle (left deltoid) and kidney differed between the infants who were treated for PDA and those who were not (p = 0.01 for both). As a screen for a PDA requiring intervention, deltoid S(t)O(2) had sensitivity 77% and specificity 83%, and kidney S(t)O(2) had sensitivity 85% and specificity 83%. Following treatment with indomethacin, the low S(t)O(2) in the deltoid and kidney increased toward the range seen in patients who did not require treatment of a PDA. Inter- and intra-observer variability ranged from minimal to high.

CONCLUSION

This pilot study of a portable NIRS device shows encouraging efficacy in identifying ELBW infants who were likely to benefit from early echocardiography and subsequent intervention to close a PDA. Further study is warranted.

Safety of DTaP–IPV–HIb–HBV hexavalent vaccine in very premature infants

OBJECTIVES

To assess the clinical safety of DTaP-IPV-HIb-HBV hexavalent immunization in very premature infants and to verify if the first administration of vaccine is by itself a reason for close monitoring hospitalized VLBW infants born at less than 31 weeks' gestation.

PATIENTS AND METHODS

Eighty-one preterm newborns less than 31 weeks' gestational age, admitted in the NICU, were eligible to be immunized with hexavalent vaccine under close monitoring, including pre-and post-immunization continuous monitoring of heart rate, oxygen saturation, respiratory rate, resistance index at the anterior cerebral artery and ECG cQT interval.

RESULTS

Of the 81 eligible premature newborns, 36 were graduated from the NICU before the least date for immunization, at 7 weeks of age. The other 45 were vaccinated in the NICU and entered the study. Twenty-three of them were under medical treatment for chronic disease at the time of the immunization while 22 were healthy and stable. Five infants (11%) had apnoea/bradycardia/desaturation, related to vaccine administration and required medical support. All five infants were in the group of newborns with chronic disease (21.7% prevalence of adverse reactions in this group). No significant variation of cQT or RI before and after the immunization was observed either in the whole groups of patients or in the five infants who showed cardio-respiratory events related to vaccination.

CONCLUSIONS

Hexavalent DTaP-IPV-HIb-HBV immunization is not associated with cardiac electric activity and cerebral blood flow variations in both stable and unstable very premature infants. However, it can cause apnoea/bradycardia/desaturation in premature babies with chronic disease. Therefore, if the baby is in the NICU for chronic diseases at 2 months post-birth, it should be monitored for apnoea, bradycardia and desaturation in association with vaccination. Hospitalized healthy preterm infants without chronic disease and therapy seem to be less vulnerable to cardio-respiratory adverse reactions. Nevertheless, it is advisable to immunize and monitor them at 8 weeks before discharge instead of possibly delaying immunization for several weeks and not monitor them.

Outcome following patent ductus arteriosus ligation in premature infants: a retrospective cohort analysis

Background

The patent ductus arteriosus (PDA) is an important problem in premature infants. Surgical PDA ligation is usually only be considered when medical treatment has either failed or was contraindicated. The aims of our study were to determine the mortality and morbidity following patent ductus arteriosus ligation in premature infants, and whether prostaglandin synthetase inhibitor (PSI) use prior to ligation affects outcome.

Methods

A retrospective case note review study to determine the outcome of premature infants undergoing patent ductus arteriosus ligation in one tertiary neonatal intensive care unit and two paediatric cardiothoracic centres.

Results

We had follow-up data on 87 infants. Cumulative mortality rates at 7 days, 30 days and at hospital discharge were 2%, 8% and 20% respectively. The incidence of chronic lung disease, intraventricular haemorrhage, necrotising enterocolitis and retinopathy of prematurity were 77%, 39%, 26% and 28% respectively. There was no difference in mortality, incidence of chronic lung disease or duration of oxygen dependence between those who had and those who had not received a PSI prior to surgical ligation. In those who had received 2 or more courses of PSI prior to surgical ligation, there was a trend to increase in the duration of oxygen therapy and chronic lung disease, but no difference in mortality.

Conclusion

This study shows that patent ductus arteriosus ligation is a relatively safe procedure (30 day survival 92%) but there is substantial late mortality and a high incidence of morbidity in the survivors. 2 or more courses of PSI prior to surgical ligation trends to increased oxygen dependence and chronic lung disease. This high risk population requires careful follow-up. A definitive prospective cohort study is lacking.