Evaluation of cerebral electrical activity and cardiac output after patent ductus arteriosus ligation in preterm infants

Towards integrative neuromonitoring of the surgical newborn: A systematic review

BACKGROUND

The altered neurodevelopment of children operated on during the neonatal period might be due to peri-operative changes in the homeostasis of brain perfusion. Monitoring of vital signs is a standard of care, but it does not usually include monitoring of the brain.

OBJECTIVES

To evaluate methods of monitoring the brain that might be of value. We also wanted to clarify if there are specific risk factors that result in peri-operative changes and how this might be evaluated.

DESIGN

Systematic review.

DATA SOURCES

A structured literature search was performed in MEDLINE in Ovid, Embase, Cochrane CENTRAL, Web of Science and Google Scholar.

ELIGIBILITY CRITERIA

Studies in neonates who received peri-operative neuromonitoring were eligible for inclusion; studies on neurosurgical procedures or cardiac surgery with cardiopulmonary bypass and/or deep hypothermia cardiac arrest were excluded.

RESULTS

Nineteen of the 24 included studies, totalling 374 infants, reported the use of near-infrared spectroscopy. Baseline values of cerebral oxygenation greatly varied (mean 53 to 91%) and consequently, no coherent results were found. Two studies found a correlation between cerebral oxygenation and mean arterial blood pressure. Five studies, with in total 388 infants, used (amplitude-integrated) electro-encephalography to study peri-operative brain activity. Overall, the brain activity decreased during anaesthesia and epileptic activity was more frequent in the peri-operative phase. The association between intra-operative cerebral saturation or activity and neuro-imaging abnormalities and/or neurodevelopmental outcome was investigated in six studies, but no association was found.

CONCLUSION

Neuromonitoring with the techniques currently used will neither help our understanding of the altered neonatal pathophysiology, nor enable early detection of deviation from the norm. The modalities lack specificity and are not related to clinical (long-term) outcome or prognosis. Accordingly, we were unable to draw up a monitoring guideline.

The impact of a dedicated patent ductus arteriosus ligation team on neonatal health-care outcomes

OBJECTIVE

The decision to perform patent ductus arteriosus (PDA) ligation is controversial. Patient selection is oftentimes poorly standardized, leading to delays in referral and inappropriate intervention. A system for PDA ligation categorization and triaging process was introduced in 2006 at a quaternary hospital in Canada to streamline referrals and enhance perioperative care. We aimed to evaluate the impact of this dedicated PDA ligation triaging system comparing pre- and postimplementation of this system.

STUDY DESIGN

We performed a retrospective chart review. Demographic and cardiorespiratory data of neonates ⩽30 weeks gestation age at birth, who were referred for and/or had a PDA ligation performed during two distinct epochs (EPOCH 1 (2003 to 2005) and EPOCH 2 (2010 to 2012)), were analyzed. All surgeries were performed at The Hospital for Sick Children, the regional referral center for PDA ligation. The primary outcome was incidence of PDA ligation and procedural cancellations. Secondary outcomes included postoperative need for cardiovascular or respiratory support. Subgroup analysis was performed in neonates <1000 vs >1000 g at the time of surgery during both epochs.

RESULT

A total of 198 neonates underwent surgery with no difference in baseline demographics between epochs. The incidence of PDA ligation as a proportion of total live births under 30 weeks in Central East Region of Ontario was lower in the second epoch (EPOCH 1: 117/1092 (10.7%) vs EPOCH 2: 81/1520 (5.3%)). During the second epoch, 24% of referrals for surgery were canceled after review by our PDA ligation team. There were no overall differences in the proportion of neonates with oxygenation failure, ventilation failure or Post-Ligation Cardiac Syndrome (PLCS), after surgery, between epochs. The proportion of neonates who developed systemic hypotension was higher in patients <1000 g (n=34 (34%) vs n=17 (17.4%), P=0.01) at the time of surgery. In addition, we identified a reduction in the proportion of neonates <1000 g who developed PLCS in EPOCH 2. On the contrary, there was an increase in the proportion of neonates >1000 g who developed ventilation failure in EPOCH 2.

CONCLUSION

The presence of dedicated triaging and management system enhances efficiency of referral process through careful selection of patients for PDA ligation and optimizes perioperative management. We demonstrated a reduction in the incidence of PDA ligation without any negative impact on short-term neonatal morbidity. The use of targeted neonatal echocardiography in the assessment of PDA shunt volume and guiding postoperative decision making is likely to have contributed to these findings.

What is new for patent ductus arteriosus management in premature infants in 2015?

PURPOSE OF REVIEW

A patent ductus arteriosus (PDA) in premature infants is common and is associated with a number of adverse outcomes. The purpose of this review is to discuss recent literature in PDA diagnosis and management.

RECENT FINDINGS

The diagnosis of a 'hemodynamically significant' PDA is challenging and a robust definition is lacking. The risks and benefits of therapies, either medical or surgical, designed to close the PDA, are controversial. Oral acetaminophen has gained increasing attention as an alternative pharmaceutical agent for PDA closure in premature infants, although safety concerns remain. Compared to surgical ligation, transcatheter PDA closure may be associated with less risk and fewer adverse events. Both aggressive and conservative management of PDA has similar clinically important outcomes, although the strength of evidence is derived mostly from cohort studies.

SUMMARY

Clinicians should weigh the potential adverse effects of pharmaceutical or surgical PDA closure against the likelihood of spontaneous closure. The infant population most likely to benefit from PDA closure remains ill-defined and clinical context is recommended.