Nights, weekends the worst time to suffer cardiac arrest

People who have a cardiac arrest in the hospital at night or on the weekend are far less likely to survive than those who suffer one during the day, U.S. researchers said.

Studies suggest this may be at least partly because of inadequate staffing at off-peak hours.

The researchers found only 14.7 percent of people whose hearts stop pumping during the night survive, compared with nearly 20 percent of people during the day.

Cardiac arrest occurs when the heart stops circulating blood. Without cardiopulmonary resuscitation or CPR and often a shock from a defibrillator, patients can die within minutes.

"Doing the right thing and doing it quickly is very important," said Dr. Mary Ann Peberdy of Virginia Commonwealth University in Richmond.

She said studies at individual hospitals suggested staffing played a role in whether a patient survived a cardiac arrest.

Other studies have shown that doctors make more mistakes at night, hospitals have fewer nurses per patient working at night and that fewer experienced supervisors work the night shift.

Peberdy wanted to see how this affected survival of cardiac arrest. Her team scoured the National Registry of Cardiopulmonary Resuscitation, which included survival data for more than 86,000 adults who had heart attacks in more than 500 U.S. hospitals between January 2000 and February 2007.

They split up the data by time of day, with the day/evening defined as 7 a.m. to 10:59 p.m., night as 11 p.m. to 6.59 a.m. and weekends starting at 11 p.m. Friday and running through 6:59 a.m. Monday.

"We factored in how sick people were, what their initial rhythms were. None of that overshadowed the time of day," Peberdy said in a telephone interview.

"Weekend nights were pretty much the same as week nights. Weekend days were kind of in between week days and nights," she said.

She said the difference by time of day held regardless of whether a patient was in a bed with a heart monitor or even in the intensive care unit.

"I think the study confirms what some of us have suspected for a while: That how we staff the hospital determines how well patients do," said Dr. Graham Nichol, who helps oversee the NRCPR registry for the American Heart Association.

Peberdy said the study suggests hospitals need to focus on improving their resuscitation systems in off-hours.