Survival statistics are not good for those who suffer cardiac arrest outside the hospital.
Although about 50 percent of people who arrest are revived after attempted resuscitation, only about 10 percent of these survive to leave the hospital. And almost half of the survivors suffer some level of brain impairment from hypoxia.
There’s new evidence, however, that physicians may be drawing conclusions too soon about survival outcomes. They may need to allow comatose cardiac arrest patients much more time to awaken before making a prognosis.
Bentley Bobrow, professor at the University of Arizona Colleges of Medicine, said:
“Most patients are comatose after resuscitation and accurately predicting those who will wake up can be extremely challenging.
There are many factors involved, but we know that it is common for doctors to try to decide who will and who won’t wake up after 24 to 48 hours of hospitalization. However, our study found that a substantial number of cardiac arrest victims wake up longer than many people would expect.
Sometimes they awaken from coma five, six, or seven days after being admitted to the hospital and many of these have a good neurological outcome.”
Among 573 out-of-hospital cardiac arrest patients who completed targeted temperature management (cooling the body to protect the brain), 60 woke up at least 48 hours after rewarming. Eight patients became responsive more than seven days after rewarming, six of whom were discharged with good neurological scores.
No Reliable Predictive Factors
One of the important findings was no predictive factors reliably identified who would awaken early or late.
“We were surprised by the large proportion of cardiac arrest survivors who woke up more than three days after their arrest and went home with their families,” Bobrow says.
“While targeted therapeutic hypothermia has been shown to improve outcomes, no validated system currently exists for predicting when patients receiving this treatment will awaken from coma. Physicians and family members may need to wait longer than the traditional three days before making irrevocable decisions about brain function recovery and possible withdrawal of care.”
Irisawa, Taro et al
Duration of Coma in Out-of-Hospital Cardiac Arrest Survivors Treated With Targeted Temperature Management
Annals of Emergency Medicine; DOI: http://dx.doi.org/10.1016/j.annemergmed.2016.04.021
Image: Von Kalumet, CC BY-SA 3.0