CHICAGO — Plane tickets, check. Passport, check. Medical evacuation insurance?

With summer vacation season approaching, experts advise international travelers to protect themselves against medical emergencies — from registering in advance with the State Department, which helps locate doctors abroad and arrange emergency medical flights, to buying supplemental insurance or stand-alone medical evacuation policies.

Thousands of American travelers each year are flown home with medical assistance because of health emergencies. Car accidents and heart attacks are among the most common reasons.

"Americans have the concept that when they travel, their health insurance travels with them," said Dan McGinnity, vice president for North America for Travel Guard travel insurance. But most regular health insurance plans don't cover costly evacuations. And finding that out after an emergency can be catastrophic.

• Check policies to see what kind of expenses are covered, said Susan Pisano of America's Health Insurance Plans. Most will pay for emergency care outside the United States — but for leisure travelers it may not include medical evacuation.

The federal Centers for Disease Control and Prevention recommends supplemental health insurance, including medical evacuation, if your existing policy is lacking.

• Short-term policies typically cost about 4 percent to 8 percent of the total per-person trip price. At Stevens Point, Wis.-based Travel Guard, coverage for a $2,000 trip would be about $120.

• The travel insurance trade group has a list of member companies on its website, where it also offers tips. The State Department's website also has a link to medical evacuation companies.

Lynda Bruner, a sales executive from Bel Air, Md., fell ill with what she thought was heat exhaustion on the last day of a Dominican Republic vacation.

Soon she developed breathing problems and went into cardiac arrest. Doctors revived her, but she remained in a coma for three days. Bruner, 60, awoke at a hospital in Florida, where she had arrived via a medical flight arranged by Medex. The company arranged for Bruner's flight with a nurse to Maryland and helped her husband deal with Dominican doctors.

Costs were more than $15,000, but were covered by health insurance her employer provides — a benefit she didn't know about in advance. Bruner had also bought extra travelers' insurance.

U.S. doctors found and removed a cyst, and Bruner recovered. "Even if you never need travel health insurance," Bruner said, "just that sense of security" is worth it.