10/27/2009 Why hypothermia? Nathan Ruch, MD FACEP How does it work? Who can we help? h h l ? What is the pre ‐ hospital experience? Unknown ECG tracings. 74yo male with funny feeling in his chest while shopping for shoes Prior CABG Prior CABG Medications are metoprolol and aspirin Patient is a retired pharmacist 25 with suffer cardiac arrest during this talk About 1000 Americans today Less than half make it to the hospital h h lf k h h l 1
10/27/2009 Cardiac arrest 450,000 sudden deaths per year in the US Greater than 90% mortality rate <10% discharged from the hospital No significant decline over past few decades despite g p p Many who “survive” have poor neurologic h h l new drugs and improved access to electrical outcome defibrillation Return of spontaneous circulation (ROSC) Many patients go on to die during subsequent hospitalization Neurologic impairment often remains as a lasting morbidity First reported 50 years ago Decreased core temp reduces metabolic demand Abandoned due to resource requirements and b d d d d lack of proven benefit 49 year old with pain in right arm that began while spreading mulch No past medical history No past medical history 2
10/27/2009 Mild Hypothermia 90 ‐ 95F (32 ‐ 35C) Moderate Hypothermia Moderate H pothermia 82 ‐ 89F (28 ‐ 32C) Severe Hypothemia <82 (<28C) Nobody really knows Reduced basal cellular energy requirements Reduced free radical production d d f d l d Improved cell membrane stability Improved immune function Decreased cytokine production 73yo woman with palpitations Some left chest pain and dizziness 3
10/27/2009 77 patients 43 Hypoothermia 34 Normothermia 34 Normothermia Results 49% good outcome with hypothermia 26% good outcome with normothermia AHA – 2005 Guidelines ILCOR – 2002 Consensus statement Unconscious adults with ROSC after out of hospital cardiac arrest should be cooled to 32 ‐ 34C for 12 ‐ 24 hours when the initial rhythm is VF 34C for 12 24 hours when the initial rhythm is VF Such cooling may be useful for other rhythms and in hospital cardiac arrest 4
10/27/2009 Yes 13% No 87% Duration on non ‐ perfusing rhythm Bystander CPR Early defibrillation – AED’s l d f b ll Quality of CPR Age Therapeutic hypothermia One out of 5 hospital deaths is sudden cardiac arrest. Overall survival in US is 5 8% Overall survival in US is 5 ‐ 8% Good neurologic outcome in 3% of out of hospital arrests. 5
10/27/2009 Surface cooling (cooling blankets/ice bags) Endovascular catheters Cool IV fluids C l fl d Cardiopulmonary bypass Cooling caps/helmets Rectal Esophageal Tympanic Oral PA catheter Bladder Axilla 6
10/27/2009 Unintentional overcooling <32C Optimal duration unknown Coagulopathy 12 ‐ 24 hours Ventricular arrhythmias l h h Shivering Sh Increased risk of infection Active rewarming 1C/HR Below 30C defibrillation may not be effective Heating blanket Warm IV fluids May help overcome institutional inertia May aid in directing post arrest patient to most capable hospitals capable hospitals Pre ‐ hospital protocols mitigate hospital delays Improves outcome Requires minimal equipment and training 82yo woman who slipped and struck her head while reaching for a pot in the kitchen Triage heart rate of 58 Triage heart rate of 58 Patient denies syncope or other symptoms ECG done by tech with no order from MD 7
10/27/2009 www.wakeems.com/saem Wake County/Raleigh, NC: All calls receive EMD from a single, high ‐ volume Single, 3 rd service EMS System with 65,000 calls/year center Reliable firefighter first response Reliable firefighter first response Fire first response with AED and compressions Fire first response with AED and compressions Resident population of ~825,000 (add 100 per day) Paramedic response with transport ambulances Post ‐ resuscitation patients are selectively transported Supervisory response at paramedic level to one of 2 high volume PCI centers Baseline [Jan 2004 ‐ Apr 2005]: Traditional CPR, ROSC after cardiac arrest not related to trauma focus on airway or hemorrhage New CPR [Apr 2005 ‐ Apr 2006]: Continuous New CPR [Apr 2005 Apr 2006]: Continuous Age 16 years or greater Age 16 years or greater compressions, delayed intubation for VF/VT Female without obviously gravid uterus Impedance Threshold Device (ITD) [Apr 2006 ‐ Oct Initial temperature >34 C 2006] Patient is intubated (no RSI) Induced Hypothermia [Oct 2006 ‐ Oct 2007] Patient remains comatose without purposeful response to pain 8
10/27/2009 All EMS records are maintained in an electronic Age less than 16 database Obvious traumatic origin of arrest Records with any of the following characteristics Records with any of the following characteristics EMS witnessed arrest S d are reviewed to determine if cardiac arrest Arrest not in EMS control occurred: Prison facilities EMS Patient Disposition = cardiac arrest Out ‐ of ‐ system intercept CPR procedure is recorded Arrests under direction of non ‐ EMS physician Defibrillation is recorded Data were analyzed using logistic regression Primary outcome was the proportion of OOH ‐ CA patients for whom resuscitation was attempted that Covariates offered for the regression: survived to discharge in baseline vs. hypothermia g yp Age A phases Gender Secondary outcomes include (by phase): Response time for the first defibrillator Pulse at emergency department, survival to admission, Witnessed status neurological intact survival to discharge Location Additionally, results were stratified by initial rhythm Total OOH-CA N= 1198 3124 OOH ‐ CA occurred during the study period Baseline N = 372 1442 obvious deaths (no resuscitation attempted) 1682 attempted resuscitations New CPR New CPR N= 319 N= 319 484 of 1682 were excluded due to: 119 not under EMS control/not a code ITD N= 148 109 obvious traumatic origin 70 under the age of 16 Hypothermia N= 359 206 EMS witnessed 1198 met inclusion criteria 9
10/27/2009 Mean Age 65 Percent male 58% 11.6% 16 Private Residence 81% 8.2% P<0.05* 14 7.3% 12 Witnessed Status 36% 10 4.6% Bystander CPR 36% 8 6 Mean Defibrillator 5.3 – 6.1 mins 4 Response 2 0 Initially VF/VT 26% Baseline New CPR ITD Hypo * when compared with baseline NOTE: no statistically significant difference between study periods 37% 40 P <0.05 * 8 P<0.05* 35 29% 7.8% 7 30 6 22% 6.2% 25 5 Percent 20 Neuro survival survival 4 4 12% 12% 4.4% 4 4% Intact 15 3 10 2 1.9% 5 1 0 0 Baseline New CPR ITD Hypo Baseline New CPR ITD Hypo Treatment Period Treatment Period * When compared with baseline * When compared with baseline * P<0.05 * 35 * 28% 35 30 25 30 20 25 Neuro eu o 20% 20% Intact 15 17% 20 * Baseline 10 15 * Hypo 10% 5 10 0 Baseline New CPR ITD Hypo 5 Treatment Period 0 Pulse @ ED Admit D/C Neuro * When compared with baseline * P <0.05 when compared with baseline 10
10/27/2009 Confounders Induced hypothermia is not experimental therapy Removal of stacked defibrillations Protocol driven pre and post resuscitation cardiac Protocol ‐ driven pre ‐ and post ‐ resuscitation cardiac arrest care Improvement with procedures due to repetition Hawthorne effect Intention ‐ to ‐ treat analysis Part of standard therapy post arrest (IIb/Ilb) Few complications Not expensive Time sensitive Impacts outcome (NNT 8) 14 yo girl with palpitations Takes verapamil 240mg Similar episodes in the past S l d h 11
10/27/2009 12
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