Can anesthesia in infants affect IQ scores?



About 10,000 newborns receive general anesthesia for congenital heart defects every year, and the more exposure they have to inhaled anesthetic agents, the greater effect it may have on their neurologic development, investigators at Children’s Hospital of Philadelphia reported in a study of newborns with hypoplastic left heart syndrome.

While previous studies have linked worse neurodevelopment to patient factors like prematurity and genetics, this is the first study to show a consistent relationship between neurodevelopment outcomes and modifiable factors during cardiac surgery in infants, Laura K. Diaz, MD, and her colleagues reported in the August issue of the Journal of Thoracic and Cardiovascular Surgery (J Thorac Cardiovasc Surg. 2016;152:482-9).

They studied 96 patients with hypoplastic left heart syndrome (HLHS) or similar syndromes who received volatile anesthetic agents (VAA) at their institution from 1998 to 2003. The patients underwent a battery of neurodevelopmental tests between the ages of 4 and 5 years that included full-scale IQ (FSIQ), verbal IQ (VIQ), performance IQ (PIQ), and processing speed.

“This study provides evidence that in children undergoing staged reconstructive surgery for HLHS, increasing cumulative exposure to VAAs beginning in infancy is associated with worse performance for FSIQ and VIQ, suggesting that VAA exposure may be a modifiable risk factor for adverse neurodevelopment outcomes,” Dr. Diaz and her colleagues wrote.

While survival has improved significantly in recent years for infants with hypoplastic left heart syndrome, physicians have harbored concerns that these children encounter neurodevelopmental issues later on. Dr. Diaz and her colleagues acknowledged that previous studies have shown factors, such as the use of cardiopulmonary bypass (CPB) and hospital length of stay, that could affect neurodevelopment in these children, but the findings have been inconsistent. Instead, those studies have shown such patient-specific factors as birth weight, ethnicity, and hereditary disorders were strong determinants of neurodevelopment in infants who have cardiac surgery, Dr. Diaz and her coauthors pointed out.

Their own previous study of patients with single-ventricle congenital heart disease concurred with the findings of those other studies, but it did not evaluate exposure to anesthesia (J. Thorac. Cardiovasc. Surg. 2014;147:1276-82). That was the focus of their current study.

Among the study group, 94 patients had an initial operation with CPB in their first 30 days of life. All 96 infants in the study group had additional operations, whether cardiac or noncardiac. The study tracked all anesthetic exposures up until the neurodevelopment evaluation in February 2008. All but 2 patients had initial VAA exposure at less than 1 year of age, and 45 at less than 1 month of age. Deep hypothermic circulatory arrest was used uniformly for aortic arch reconstruction.

The study used four different generalized linear models to evaluate anesthesia exposure and neurodevelopment.

For both FSIQ and PIQ, total minimum alveolar concentration hours were deemed to be statistically significant factors for lower scores. For PIQ, birth weight and length of postoperative hospital stay were statistically significant. For processing speed, gestational age and length of hospital stay were statistically significant.

Dr. Diaz and her colleagues said their findings are preliminary and do not justify a change in practice. “Prospective randomized, controlled multicenter clinical trials are indicated to continue to clarify the effects of early and repetitive exposure to VAA in this and other pediatric populations,” the study authors concluded.

Dr. Diaz and the study authors had no financial relationships to disclose.

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