Physician Utilization of Therapeutic Hypothermia Following Resuscitation from Cardiac Arrest James W. Rhee, MD April 29, 2004 The University of Chicago Emergency Medicine Residency

Introduction Cardiac arrest –Greater than 90% mortality rate –No significant decline over past few decades despite new drugs and improved access to electrical defibrillation Return of spontaneous circulation (ROSC) –Many patients go on to die during subsequent hospitalization –Neurologic impairment often remains as a lasting morbidity

Studies HypothermicNormothermic Alive at 6 months with favorable neurologic status 53% (75/136)35% (54/137)

ILCOR Advisory Statement Unconscious adult patients with ROSC after out-of-hospital VF cardiac arrest should be cooled to 32°C - 34°C for hours Possible benefit for other rhythms or in-hospital cardiac arrest

Current Use Physician Utilization –Physician utilization of therapeutic hypothermia following ROSC after cardiac arrest remains unclear Physician Experience –Initial experiences with hypothermia Guide future investigations Development of critical pathways

Survey We conducted an internet-based survey of U.S. physicians in emergency medicine, pulmonary/critical care, and cardiology –Evaluate physician utilization of hypothermia therapy –Assess physician opinions and experience regarding induced hypothermia after cardiac arrest

Methods Institutional Review Board approval Health Insurance Portability and Accountability Act of 1996 – compliant

Methods 2000 electronic mail addresses randomly chosen –American College of Emergency Physicians –American Thoracic Society –American Heart Association Invitation to participate in survey sent to each address with a hyperlink leading to the survey itself

Methods Survey published via commercial survey provider (Infopoll.com, Dartmouth, Canada) Survey comprised of twelve questions –Demographic information Field of practice, geographic location, level of training, etc. –Use of induced hypothermia Methodology, reasons for non-use, etc. –Free response at end of survey

Methods Results compiled by survey provider software Analysis and tabulation performed using a spreadsheet application (Excel, Microsoft Corp., Redmond, WA)

Results s 1400 hits 265 responses (19%)

Demographics

9% 27% 13% 20% 30%

Use of Therapeutic Hypothermia

Critical Care (n=33) Cardiology (n=64) Emergency Medicine (n=109) All respondents (n=263) YesNo 5% 95% 11% 89% 29% 71% 13% 87% Use of Therapeutic Hypothermia by Clinical Specialty

Not enough data Havent considered it Not in ACLS guidelines Too technically difficult Current methods cool too slow Unsatisfactory initial attempts 0% 10% 20% 30% 40% 50% Reason for nonuse- Percentage of respondents 49% 32% 19% 9% 4% Reasons Against Use of Hypothermia as a Therapeutic Tool

Cooling Technique Cooling blankets Ice / cold liquid packing Ice / cold liquid gastric lavage IV cooling catheter Cooling mist Other method 0% 10% 20% 30% 40% 50% Cooling technique Percentage of respondents 50% 15% 13% 2% 17%

Free Response Have not heard of this treatment option 3 Resistance from hospital or other physicians 3 I am interested in technique, want to learn more 3 Plan on using it in the future -- now developing protocol 7 Literature not yet convincing 4 Lack of training -- too many resources required 5 Total number of free responses80

Hypothermia Not Yet Incorporated Physicians have not yet incorporated the use of therapeutic hypothermia after cardiac arrest despite strong data and published guidelines recommending its use This conclusion appears to be consistent across the three specialties queried

Limitations Reflects practice at one point in time Selection bias – respondent population was skewed towards physicians practicing in larger hospitals and teaching institutions Western US not as well represented

Best Case As physicians at academic institutions and tertiary or referral hospitals were overrepresented – likely represents best case of current practice –Assume utilization of this new treatment modality in the greater medical community will be less than in larger academically-oriented hospitals

Reasons for Lack of Incorporation Physicians not aware of strong literature supporting use of induced hypothermia Not part of standard guidelines –Advanced Cardiovascular Life Support (ACLS) Technical constraints

Actions to Promote Use Physician education Update ACLS Share experiences and protocol development

Future Technology Novel coolant fluids Cold IV fluids Cooling catheters

Research Method Timing Mechanism

Summary Physician use of hypothermia induction in patients resuscitated from cardiac arrest is low Reasons why physicians have not used hypothermia include lack of awareness of supporting data, technical constraints, and the lack of hypothermia protocol incorporation into ACLS Better understanding of the pathophysiology of resuscitation and the injury processes on which hypothermia acts will serve to further promote the use of this promising method to save lives

Acknowledgements Ben Abella, MD Annie Hueng Lance Becker, MD Terry Vanden Hoek, MD Lynne Harnish ERC