Wednesday, December 14, 2016

Lengthy anesthesia and brain damage in fetuses, neonates and infants

Long surgeries can cause neurological damage in babies, fetuses, and toddlers.

When infants, young children, or pregnant women need surgery the risk of brain or neurologic injury from anesthesia has long been a concern.

In a Drug Safety Communication sent today the US Food and Drug Administration (FDA) said that anesthesia administered for more than three hours may adversely affect the developing brains of children younger than three and the fetus in pregnancies that are in the third trimester.  The same is true for repeated surgeries.

That includes 11 drugs that block N-methyl-D-aspartate receptors or potentiate gamma-aminobutyric acid activity, or both.

“No specific medications have been shown to be safer than any other” the FDA noted.

“We recognize that in many cases these exposures may be medically necessary and these new data regarding the potential harms must be carefully weighed against the risk of not performing a specific medical procedure,” Janet Woodcock, MD, director of the agency’s Center for Drug Evaluation and Research said in a statement accompanying the safety announcement. While some common procedures like hernia repair generally take far less than three hours, open heart procedures can last up to eight hours.

The warning is based on an FDA evaluation of published studies in pregnant animals and young animals. All showed loss of nerve cells in the brain or effects in the animals’ behavior or ability to learn.  

In another study published in 2015, Australian researchers looked at results in infants in 28 hospitals seven nations, including the US, who had anesthesia for less than an hour during hernia repair surgery.

The children were assessed two years after the surgery to see if there were adverse neurodevelopmental outcomes.

They found they showed no such signs, but the results were taken as not useful for weighing the risks in longer procedures.

That research group is planning to follow their study group through five years post-surgery.
The full document “FDA review results in new warnings about using general anesthetics and sedation drugs in young children and pregnant women” lists the drugs and has links to studies.

The U.S. Food and Drug Administration (FDA) is warning that repeated or lengthy use of general anesthetic and sedation drugs during surgeries or procedures in children younger than 3 years or in pregnant women during their third trimester may affect the development of children’s brains…

Health care professionals should balance the benefits of appropriate anesthesia in young children and pregnant women against the potential risks, especially for procedures that may last longer than 3 hours or if multiple procedures are required in children under 3 years. Discuss with parents, caregivers, and pregnant women the benefits, risks, and appropriate timing of surgery or procedures requiring anesthetic and sedation drugs.

Parents and caregivers should discuss with their child’s health care professional the potential adverse effects of anesthesia on brain development, as well as the appropriate timing of procedures that can be delayed without jeopardizing their child’s health.

Pregnant women should have similar conversations with their health care professionals. Also talk with them about any questions or concerns…

Based on FDA’s understanding of brain development, the data suggest that the fetuses of women in their third trimester of pregnancy and children younger than 3 years are most likely vulnerable to this effect.

• Recent studies in children suggest that a single, relatively short exposure to general anesthetic and sedation drugs in infants or toddlers is unlikely to have negative effects on behavior or learning. More research is still needed to fully understand how anesthetics might affect brain development, especially longer or repeated exposures and in more vulnerable children.

• Most anesthetic drugs have been shown to cause these negative effects on brain development in different species of animals, and no specific medications have been shown to be safer than any other…

In published juvenile animal studies, use of anesthetic and sedation drugs that block N-methyl-D-aspartate (NMDA) receptors and/or potentiate gamma-aminobutyric acid (GABA) activity for longer than 3 hours has been demonstrated to increase neuronal apoptosis in the brain resulting in long-term cognitive deficits (see List of General Anesthetic and Sedation Drugs Affected by this
Label Change)…

Some published studies suggest that similar deficits in cognition and behavior may occur in children, particularly after repeated or prolonged exposures to anesthetic drugs early in life. These studies have limitations, and it is not clear if the effects reported are due to the anesthetic/sedation drugs, or to other factors such as the surgery or underlying illness.

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