Improving Neurologic Outcomes of Cardiac Arrest Patients Through Therapeutic Hypothermia

Friday, 25 July 2014

Alfie Jay C. Ignacio, DNP, MSN, RN
Emergency Department, Torrance Memorial Medical Center, Torrance, CA

Improving Neurologic Function After Cardiac Arrest Through Therapeutic Hypothermia


Post cardiac arrest patients have a high mortality rate and poor neurologic outcomes in spite of standard post resuscitation care and intensive critical care monitoring. Out of 164,000 cardiac arrests occurring in the United States annually, 65-95 % dies. Those that survive suffer adverse health outcomes including physical disabilities, physiologic instability, and systemic complications.



The American Heart Association recommends initiation of therapeutic hypothermia to patients who remain comatose after resuscitation from sudden witnessed out-of-hospital cardiac arrest. Therapeutic hypothermia is an intervention that cools the post arrest patient to a temperature of 32-34°C with iced saline or other surface cooling measures after the return of spontaneous circulation. The temperature is maintained for a period of 18-24 hours. Research has shown that patients who undergo therapeutic hypothermia are more likely to survive to hospital discharge compared to standard post-resuscitation care. Therapeutic hypothermia has been shown to improve neurologic outcomes and decrease mortality following cardiac arrest.


To implement and evaluate the effectiveness of therapeutic hypothermia on neurological outcomes and survival rate of post cardiac arrest patients.


A policy and protocol was developed by the clinical nurse specialist in collaboration with the ED and ICU nursing staff, ED physicians, respiratory therapy, physical therapy, pharmacy, and clinical informatics which outlined the approach for instituting immediate hypothermia in patients remaining comatose following out-of –hospital cardiac arrest. The goal was to start therapeutic hypothermia within six hours after return of spontaneous circulation and to keep the patient’s temperature at 33° C for a period of 18-24 hours. Staff was educated about the protocol and a therapeutic hypothermia kit was provided to the ED and ICU which contain the protocol and supplies to initiate hypothermia.


Findings were based on mortality rate and neurologic outcomes. Modified Rankin Scale (MRS) was used to measure neurologic outcomes. An MRS score of two or lower indicates a good functional outcome. There were 43 patients who met the criteria for therapeutic hypothermia since the program started in 2011. Twenty patients survived and twenty-three patients died following hypothermia. Of the 20 patients who survived, seventeen patients survived with good neurologic outcomes (MRS score of 1-2), and 3 were discharged with neurologic deficit (MRS score of 3 and above).


Results suggest therapeutic hypothermia decreases mortality rate and improves neurologic outcomes. However, continuing educational needs exist among staff to master the skills in the provision of therapeutic hypothermia. A well developed policy will guide nurses in instituting hypothermia as indicated.