SALEM — An increase in the number of patients at local emergency rooms has prompted North Shore Children's Hospital to reopen its emergency services during overnight hours.

"Volumes in the emergency department have just exploded," said Dr. Edward Bailey, chairman of pediatrics. "It's been a very bad year for viral infections — rotovirus, the flu and RSV (respiratory syncytial virus), which is most damaging to little infants and can be fatal.

"Volumes have been increasing in all of our ERs," he said, referring to North Shore Medical Center's hospital chain, which includes Salem Hospital next to Children's Hospital.

The change reopens the six beds in the children's emergency room overnight, which frees up the adult beds in the Salem Hospital ER that were being used instead.

"It's so busy that people's waiting times are increasing, and we feel terrible about that," Bailey said.

In May 2006, Children's Hospital decided to close the ER overnight and send children to the Salem Hospital ER instead and staffed it with pediatric doctors and nurses. At the time, the children's ER was only seeing 0.4 patients per hour, on average, between 2 and 6 a.m., "and it's very expensive to keep it open for that much," Bailey said.

That has since changed, prompting North Shore Children's Hospital to reopen its emergency department 24 hours a day. The change went into effect in late February.

North Shore Children's Hospital also added another nurse practitioner or pediatrician on all weekday evenings to keep up with patient demand, making for a total of three doctors or NPs.

"Taking care of kids is the greatest responsibility any of us can ever have, and we take it seriously," Bailey said. "We want everybody to go away happy."