Therapeutic Hypothermia to Improve Outcomes Post OHCA

By: L. Bloxham, E. Foley, D. Price, & L. PendergraftCollege of Nursing, University of Oklahoma - 2010

PICO Question

Population Adult survivors of cardiac arrest who have regained circulation but remain comatose

Intervention Therapeutic Hypothermia (32 to 34 C)

Comparison Maintaining Normothermia (37 C)

Outcome Reducing mortality and improving neurological outcomes

PICO Question

In adult survivors of primary cardiac arrest who have regained circulation but remain comatose, what is the effect of therapeutic hypothermia (32 to 34 C) on reducing mortality and improving neurological outcomes compared with maintaining normothermia (37 C) post-cardiac arrest?

DefinitionsAdult

18-64 years old

Normothermia 37 C

Long TermMinimum of 1 year

Cardiac ArrestCardiac arrest is defined as cessation of cardiac mechanical activity and is confirmed by the absence of signs of circulation.

American Heart Association (2009)

Definitions

ComatoseA score ranging from 3-8 using the Glasgow Coma Scale

ROSCReturn of spontaneous circulation

Therapeutic HypothermiaPatients cooled to a core temperature between 32 to 34C for 12-24 hours

Good Neurological Outcome Cerebral Performance Category (CPC) scores of one or two

American Heart association (2009)

Identification of the Problem

Every two to three minutes, someone in the United States goes into cardiac arrest.

• Out-of-Hospital cardiac arrest (OHCA) affects approximately 300,000 people in the United States annually, and survival is generally less than 10%.

• Approximately 10% to 30% of out-of-hospital cardiac arrest survivors have permanent brain injury as a result of global ischemia.

National Heart, Lung and Blood Institute (2008) Merchant, R.M., et al (2009) Barht, G. (2009)

Prevalence & Cost

• Sudden Cardiac Arrest (SCA) is a leading cause of death in the United States.*

• Cardiac arrest cost Americans 2.2 billion dollars annually in direct cost.**

*Heart Rhythm Foundation (n.d.) ** Ambrose, R. (2004)

Review of Literature

Medical ResearchSystematic ReviewRandomized Control TrialsClinical GuidelinesRetrospective StudiesObservational Studies

Review of Literature

Arrich, J., Holzer, M., Herkner, H., Müllner, M. (2009)

• Systematic review & meta-analysis. Four trials and one abstract reporting on a total of 481 patients were included in the review.

• Therapeutic Hypothermia (TH) improves survival and neurologic outcome in patients successfully resuscitated from cardiac

arrest when they meet the following criteria: out-of-hospital cardiac arrest of cardiac cause with VF/VT as first recorded rhythm.

Review of Literature

Bernard, S.A., et al. (2002)

• Randomized control trial. A total of 77 patients were randomly assigned to hypothermia or normothermia group after successful resuscitation outside of hospital.

• 49% of patients in the hypothermia group were considered to have a good outcome compared with 26% of the normothermia

group.

Review of Literature

Hypothermia After Cardiac Arrest Study Group. (2002)

• Randomized control trial. A total of 275 patients enrolled in study. Included in the study were patients 18-75 years old that had a witnessed cardiac arrest, presumably or cardiac origin, with ventricular fibrillation or non-perfusing ventricular

tachycardia as the initial rhythm.

• Systematic cooling to 32°C-34°C for 24 hours increased the chance of survival and of a favorable neurological outcome (Cerebral performance scale category 1 or 2).

Review of Literature

Nielsen, N., et al. (2009)

• Observational study. A total of 986 out-of- hospital cardiac arrest patients treated with therapeutic hypothermia (TH),

regardless of the cause of the cardiac arrest.

• Neither timing of TH nor the duration were significantly associated with the outcome of the treatment.

•After TH, 676 patients were alive (69%) of whom 401 (41%) had a good neurological outcome (CPC 1 or 2).

Review of Literature

Oddo, M., et al. (2006)

• Retrospective study. A total of 109 patients resuscitated from out of hospital cardiac arrest with initial rhythms of VF, asystole, or pulseless electrical activity (PEA). All were in a persistent coma at admission.

• In patients with VF as the initial rhythm, 55.8% of patients treated with TH had a good outcome compared to 25.6% of patients treated with standard resuscitation (SR).

•60.5% of TH patients survived to discharge compared to 44.2% of SR patients.

Therapeutic Hypothermia-Pros

• Saves lives and improves quality of life for survivors.

• Does not cause an increase in patients surviving in a persistent vegetative state.

• Side effects are predictable and can be prevented or managed easily.

• Cost effective and relatively easy to implement, the procedure lends itself well to a protocol.

Therapeutic Hypothermia-Cons

• Specific patient populations may encounter more side effects

• Eligibility criteria too narrow

• Unrealistic to have 1:1 patient/nurse ratio; as studies suggest close monitoring is required through cooling and re-warming

phase. This could particularly be a problem when cooling is initiated in ER

• Requires training, if not used often this may be a problem for units with high turnover

Summary of Findings

• Therapeutic hypothermia improves survival and neurologic outcome in patients successfully resuscitated from cardiac arrest.

• Research concluded that therapeutic hypothermia is an acceptable investment of health care dollars whose benefits justify its costs.

• Adverse events were not significantly greater in therapeutic hypothermia patients than in normothermia control groups.

Internal Method

11sd

External Method

11sd

Current PracticeHospital A: Protocol in place

Inclusion Criteria• Cardiac arrest in any

patient location• TH initiated within 6

hours of ROSC• Comatose• 18 years of age and

older

Exclusion Criteria• Refractory Shock• Systolic BP<90 mm Hg

despite fluids and pressors

• Refractory Ventricular Arrhythmia

• Coagulopathy or uncontrollable bleeding

• Pregnancy

Inclusion Criteria• Cardiac arrest• TH initiated within 6

hours of ROSC• Comatose• 18-80 years of age

Exclusion Criteria• Intracranial hemorrhage• Trauma or terminal illness• Coagulopathy or

uncontrollable bleeding• Pregnancy

Current PracticeHospital B: Protocol in place

Current PracticeHospital C: Protocol in place

Inclusion Criteria• Non-Traumatic cardiac

arrest with return of circulation

• TH initiated within 6 hours of arrest

• Systolic BP > 90 or MAP > 60 after fluid resuscitation with or without pressors

• > 12 years old

Exclusion Criteria• GCS > 8• Greater than 6 hours since

arrest• DNR• Non-mechanically ventilated

patient• Pregnancy• Active bleeding• Arrest secondary to sepsis

Recommendations

For facilities not currently initiating therapeutic hypothermia:

• Establish protocol to begin using therapeutic hypothermia.

Research has shown that therapeutic hypothermia is known to improve neurological outcomes and increase survival rates in out-of-hospital cardiac arrest.

Recommendations

For facilities currently using therapeutic hypothermia:

•Revisit inclusion criteria, as additional research is needed to ensure that all those that would benefit from therapeutic

hypothermia are included.

•Begin intervention in the ED/ER, as opposed to waiting until patient is transferred to the ICU.

Evaluating Effectiveness

• Evaluate hospital complianceDirect observation

Chart reviews

• Evaluate effectivenessAwareness Campaign, Training, & ImplementationPatient outcomes

Retrospective studies

Cost effectiveness

Suggestions for Further Study

• More randomized controlled trials with wider eligibility requirements

• Larger sample size for studies

• Prospective studies to evaluate patient outcomes greater than one year post OHCA when induced hypothermia was implemented

• Studies focused on where induced hypothermia should be implemented

New Research Questions

• Is broadening the inclusion criteria for patients to receive therapeutic hypothermia beneficial?

•Is there a decreased length of stay as a result of therapeutichypothermia?

•Would initiating hypothermia in the ambulance on the way to the hospital further increase survival?

Advanced life support. In: 2005 International Consensus Conference on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science with Treatment Recommendations. Circulation 2005 Nov 29;112(22 Suppl):III25-54.

Ambrose, R. (2004). The Cost of cardiac arrest in the workplace. Occupational Health & Safety, Retrieved from

http://ohsonline.com/Articles/2004/09/The-Cost-of-Cardiac-Arrest-in-the-Workplace.aspx?Page=2

American Heart Association. (2009). News releases: Cooling therapy for cardiac arrest survivors is as cost-effective as accepted treatments for other conditions. Retrieved from http://americanheart.mediaroom.com/index.php?s=43&item=795.

Arrich, J., Holzer, M., Herkner, H., Müllner, M. (2009). Hypothermia for Neuroprotection in adults after cardiopulmonary resuscitation. Cochrane Database of Systematic Reviews, 4, 1-33.

References

Barht, G. (2009). Cooler heart, better odds: induced hypothermia. Nursing Management, 40(7), Retrieved from

http://www.nursingcenter.com/prodev/ce_article.asp?tid=869342

Centers for Disease Control. (2009). Chronic disease prevention and health promotion: Heart disease and stroke prevention. Retrieved from http://www.cdc.gov/chronicdisease/resources/publications/AAG/dhdsp.htm

Heart Rhythm Foundation, (n. d.). Sudden cardiac arrest statistics. Heart Rhythm Facts and Stats. Retrieved from

http://www.heartrhythmfoundation.org/facts/scd.asp

Merchant, R.M., Becker, L.B., Abella, B.S., Asch, D.A., Groeneveld, P.W. (2009). Cost-effectiveness of therapeutic hypothermia after cardiac arrest. Circulation: Cardiovascular Quality & Outcomes, 2(5), 421-28.

National Heart, Lung and Blood Institute. (2008). National Institute of Health news: Automated external defibrillators and CPR are equally helpful for sudden cardiac arrest in the home. Retrieved from http://public.nhlbi.nih.gov/newsroom/home/GetPressRelease.aspx?id=256

.

References