If you have an advance directive that cherry-picks the interventions you want to receive if your heart suddenly stops, you might want to rethink your choices, according to physicians writing in JAMA Internal Medicine.

As patients and families increasingly recognize the value of specifying their wishes regarding medical treatment in case they become unable to communicate, they need to better understand the implications of their decisions, the doctors say.

People who prepare for the possibility of cardiopulmonary resuscitation (CPR) by specifying selected options – “everything but intubation” or “everything but defibrillation” – don’t realize what that can mean, they warn.

Dr. Paul Rousseau of the Wake Forest School of Medicine in Winston-Salem, North Carolina describes a 77-year-old man with advanced cancer whose code status called for a “partial” code, with “no intubation.”

So while doctors were able to restart his heart, they couldn’t place a breathing tube in his lungs per his written wish. Without the breathing tube, he didn’t get enough oxygen, and as a result, he suffered severe brain damage. He remained comatose in the intensive care unit for another two weeks before he died.

Delivery of selected options during CPR attempts is a troublesome and increasingly frequent preference that often stems from good intentions among families balancing desires to save a life and limit suffering, Rousseau wrote in his paper.

Many staff, Rousseau recounts, felt that despite honoring this patient’s advance directive, they had actually harmed him. Others worried that the patient had not understood the likely outcomes.

“You do everything you can to return functioning, or you don’t,” Rousseau told Reuters Health. “If you are a baker and not using the main ingredient, the food will not come out okay.”

Rousseau would like to see partial codes banned. “When patients survive, it can often portend messy and emotional futures for families as well as physicians, not to mention financial repercussions for hospitals,” he said.

In a linked commentary, Dr. Josue Zapata and Dr. Eric Widera, both from the University of California, San Francisco, say “partial codes” are symptomatic of communication failures.

“A partial code likely represents a partial understanding by a patient or a partial assessment of their priorities by a provider,” they write.

Zapata and Widera advise doctors to ask patients what they hope their treatments will achieve.

“Providing a list of choices may in itself be misleading in that a patient may falsely believe that if a given intervention is offered as an option by a presumably expert and well-intentioned physician, there must be at least some sort of benefit,” they say.

Outcomes after partial codes in hospitals are hard to study; scant research exists. Large-scale studies show that after a full-out resuscitation effort, including intubation, 17 percent of patients live long enough to be discharged from the hospital, according to Zapata and Widera. For patients with advanced cancer, that rate is probably no higher than 5 percent.

Bioethicist Craig Klugman from DePaul University in Chicago agrees that partial codes should not be offered.

“There are many times in medicine when one thing requires a second thing, and to separate them undermines the chance of benefit,” Klugman told Reuters Health. “To offer a ‘choose your own adventure’ procedure violates the oath to do no harm.”

But Dr. Patrick Cullinan, former medical director of an intensive care unit in San Antonio, Texas, disagrees.

Cullinan told Reuters Health that when patients request a partial code without intubation, he often uses either bag masks or BiPAP (bilevel positive airway pressure), which are noninvasive breathing therapies, instead of intubation.

“Partial DNRs (Do Not Resuscitate orders) are helpful in allowing families to feel empowered and have some input,” Cullinan said. “Those staunchly ‘all’ or ‘nothing’ don’t understand subtleties in providing the most compassionate and appropriate care. By placing an unwanted tube, you steal their last opportunity to talk to their family, to tell them ‘I love you.'”

Dr. Melissa Bregger, a chief internal medicine resident at Northwestern University’s Feinberg School of Medicine in Chicago who has extensively studied CPR and advanced life support, says that while little data exists, emerging research showing improved outcomes using bag masks instead of intubation is “somewhat promising.” Among critically ill patients, however, not much evidence supports noninvasive measures.

“It depends on what caused the code, and that’s one of the hardest things to figure out during a code,” Bregger told Reuters Health. If patients code due to dangerous heart rhythms, partial codes may prove as effective as full efforts. However, such patients would be unlikely to have participated in planning discussions to request limited measures.”

“It’s a really hard question,” she said.