Presentation on theme: "Resuscitation and Post Resuscitation Care"— Presentation transcript:
1 Resuscitation and Post Resuscitation Care Jose G. Cabanas, MD MPH FACEPPaul R. Hinchey, MD MBA FACEPOffice of the Medical DirectorAustin-Travis County EMS System
2 Austin/Travis County EMS Approximately 1.2 million citizens, 1,100 square miles, 120k EMS calls per year1,000 cardiac arrests responses per year14 Fire Departments (1,500 FF’s,)EMS Transport Agency (400 Paramedics)EMS Systems are judged by their cardiac arrest resuscitation ratesMost large cities are 5-7%King Cnty Wa 35-45%Wake Cnty NC 38-42%Austin 38%
3 Why are we talking about Cardiac Arrest Resuscitation?
4 Philosophy of Five Time Dependent Intervention Dependent Acute MI (STEMI)Acute StrokeTrauma / Surgical EmergencyIntervention DependentCardiac ArrestRespiratory DistressSophisticated providers/systems understand the difference
5 Time DependentThese conditions can not be definitively treated in the pre-hospital environmentRequires specialized intervention only available in the hospitalOutcomes are improved by early access to definitive interventionGoal is recognition and short scene interval
6 Intervention Dependent Initial treatment can be delivered in prehospital environmentOutcomes linked to prehospital interventionsGoal is identification and initiation of treatmentScene intervals are NOT critical
7 Updates in Out-of-Hospital Resuscitation and Post Resuscitation Care
8 ObjectivesDescribe the importance of continuous compressions and controlled ventilationsDiscuss what to do with the airway/drugsAcknowledge the difficulty of performing continuous compressions and the need for a scripted processDiscuss importance of on-scene post ROSC stabilizationDescribe role of resuscitation centersIdentify questions for the future
9 Why do we worry about CA Represents < 1% of our calls but… > 70% of CA arrests occur outside the hospitalDefinitive management of cardiac arrest is in the prehospital environment
10 “Stated succinctly, if ACLS care in the field cannot resuscitate the victim, ED care will not resuscitate the victim.”-2005 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care (Part 7.2: Management of Cardiac Arrest)
11 Priorities in OOHCA Changed Emphasis on compressionLimit interruptions from ANYTHINGGoal is to maximize % of time in compressionsSingle D-fib every two minutesPrecharge monitor before breakFollow d-fib immediately by compressionsDecreased importance of ventilationsFewer number of breathsEach delivered more slowly
12 So if you had to push a car, would you push a few feet and stop… So if you had to push a car, would you push a few feet and stop….. only to start again a few minutes later?
21 Importance of controlled Ventilation Normal inspiration is negative pressureEncourages blood return to the chestArtificial ventilation is positive pressureReduces blood return to the chestThe faster the ventilation rate the higher the mean intrathoracic pressureHigher MIP reduces cerebral emptying and reduces blood return to the heart
23 STOP Hyperventilating Telling providers not to hyperventilate is ineffectiveHigh adrenaline situationTendency to ventilate faster and fasterRequires conscious effort to slow ratesNeed constant reminderTiming deviceGoal directed ventilation
24 How to Deliver Ventilations Goal is to oxygenate primarily and ventilate as a secondary considerationMust provide continuous uninterrupted compressionsTraditional method is endotracheal intubation but increases interruption in compresionsSo is this a paradigm that needs to be challenged?
25 * Indicates median values reported Interrupt CPR…not ME100 Cardiac ArrestsCPR interruptions 2* (1-9)1st ETI interruption 46.5 s* (7-221 s)Total all ETI interruption s* ( s)1/3 > 1 min; ¼ > 3 minETI Interruptions 23% of all* Indicates median values reportedWang et al Ann Emerg Med
27 Advanced Airway Management AdvantagesNo mask seal requiredEasier to doLess manpowerAllows continuous compressionsDisadvantageRequires interruption of compressionsEasier to hyperventilate (rate and volume)Doesn’t provide better ventilation/oxygenation
28 173 LMA vs 200 BVM by paramedics No difference in median: Pa CO v 55.3 (p=0.06)Pa O v 71.9 (p=0.056)There is no MAGIC to these devices
29 Retrospective analysis of OOHCA 1,294 Cardiac Arrests 79% received intubation10% BVM4% Combitube/EOAAfter adjusting for age, bystander CPR, witnessed arrest and initial rhythmOR for BVM vs Advanced airway was 4.5
30 What is best vascular access? Goal is vascular access by any means that does not interrupt compressionsPreferably rapid reliable access that does not detract from other tasksBased on assumption that the drugs do anything….more on this laterIO access can be achieved in < 10 sec but which site should be used?
31 56 (65.9%) used tibial site first 88 Cardiac arrest56 (65.9%) used tibial site firstInitial success rate 89.7%3 (5.8%) dislodged18 (34%) used humerus firstInitial success rate 60%6(33%) dislodgedOverall success ratesTibia 84.5%Humerus 40%
32 So what about the drugs? Most recent quandary Standard of care is currently being challengedWill be a major change in management in your careerWho will make the first step…
33 851 patients with OOHCA randomized to: 418 given IV drugs433 given no drugsPrimary outcome hospital dischargeAlso looked at:Hosp admission with ROSCNeuro outcome at dischargeSurvival at 1 year
36 Running the ArrestCA is not the most diagnostically challenging condition so thought to be “EASY”EXECUTION is anything but…Conflicting interests of multiple tasks and the need for continuous uninterrupted compressions and infrequent occurence
38 Task Interruptions Airway interventions and IVs Ventilations Pulse checksRhythm analysisDefibrillationChanging compressorsPatient movement
39 We have limited awareness of task time in complex processes… We have limited awareness of task time in complex processes….so these interruptions should be engineered and choreographed to minimize their impact…..
40 >20 second pause for defibrillation >20 second pause for defibrillation. Appears that a ventilation was given before the compressions resumed. Compressions resume 10 seconds after shock delivery.
41 Long pause for ventilations Long pause for ventilations. Then short sequence of compressions during defib charging. Compressions resumed approximately 5 seconds after shock 1 delivered.
42 Why engineer the process? Creates uniformity:Accurate assessment of outcomesLinking specific interventions to outcomesBaseline for future modificationIn the process it:Improves outcomesImproves efficiencyReduces errors
43 Regional Variation in Incidence / Outcome 200811,898 cardiac arrests2729 had initial rhythm of V-Fib / V-Tach.954 (4.6% of total) were discharged alive.Incidence of EMS-treated CA was 52.1 persurvival ranged from 3.0% to 16.3% (median of 8.4%)Median ventricular fibrillation 12.6 persurvival ranged from 7.7% to 39.9%,
46 Professional CA resuscitation is to CPR …. … Professional CA resuscitation is to CPR …. ….what a pit crew is to changing tires
47 Pit Crew Model Same name…many versions CPR Controlled ventilations Maximize compression fractionEffective compression(rate/depth)Provider fatigueControlled ventilationsDefibEmphasis on Shock/Don’t’ shock
48 Current Goal: Less than 10 second break in every 2 minute cycle of CPR
49 Staying Alive or Another One Bites the Dust? Staying alive 103 bpm30:2100 compressions/min =18s for compressions5 s break for ventilations every 30 compressions?18 of every 23s in active compression is 78%NOT counting other breaks in CPRPit CrewContinuous compressions w/asynchronous ventilation10s break every 2 min is 92%5s break every 2 min is 96%
60 Scenario 178 y/o Wal-Mart greeter suffers cardiac arrest in the front of a store:Where do you work the cardiac arrest? Would this be different if it were in his house?When do you begin transport to the hospital?If unsuccessful when do you terminate the resuscitation?
61 Scenario 278 y/o Wal-Mart greeter has been resuscitated from CA and is being transported when he re-arrests:What would you instruct your crews to do if they were 20 min out from the hospital?What if they were 5 min out?
62 Scenario 378 y/o suffers CA at home. Wife does 2 min dispatcher directed CPR. Pt has ROSC and wakes up. Walks to couch. Crews find in CHF and treat appropriately w/meds and CPAP. FF ride w/crew to hosp. While pulling into ED bay pt goes into CA:What do you want your crews to do?
63 Take Home Message CA is not as easy as once thought Pre-hospital providers must be the expertsIts all about compressionsAirway, drugs, etc are a big ?If you want to do this well you must have universally understood goals and plan
65 Post-Cardiac Arrest Syndrome Post-cardiac arrest brain injuryResponsible for 68% of deaths of patients who survived to ICU admission (Lever, 2004)Post-cardiac arrest myocardial dysfunctionLV dysfunction, myocardial stunning, cardiogenic shockSystemic ischemia/reperfusion injuryInflammatory response, impaired vasoregulation, oxygen delivery and utilization, resulting in hypotension / MSOFPersistent precipitating pathologySTEMI, Toxic Ingestion, Hypoxia, Hemorrhage, etc.What are the components of mortality in PCAS – Improving hemodynamic status (BP, fluids) and hypothermia impacts all of them. Identifying the STEMI for immediate cath
67 Post-Resuscitation Care Goals of Post-Arrest CareMaintain Hemodynamic StabilityPreserve the BrainAvoid hyperventilationPrevent re-arrestElements of Post-Care includeVasopressor titrationTherapeutic HypothermiaEarly Cardiac CatheterizationSedationGlucose and Electrolyte ManagementI still believe there should be some attention paid to ensuring appropriate ventilation. hyperventilation in the patient with myocardial stunning is a double whammy. It is not the primary focus but it can create or worsen a perfusion problem.Please emphasize that the electrolyte management is primarily done in the ICU. To a large extent the issue with glucose is simply avoiding hypoglycemia (for EMS and the ICU) and avoiding hyperglycemia (ICU). I remain amazed at how paramedics take these things and use them as justification to do additional procedures (or at least request them). As you know, several of these post arrest care elements are over a time span that is much longer than the prehospital phase.
68 Post Cardiac Arrest Care The first 20 minutes after ROSC is the Immediate Phase of Post Cardiac Arrest SyndromePatients in these phases may be critically ill and benefit by immediate treatment AT SCENE:This is a better strategy for patient survival than rapid movement to the vehicle and rapid transport delaying or deferring key interventionsFailure to initiate immediate aggressive treatment may result in re arrest of patient or increased morbidityBe sure you place the correct degree of emphasis of time on scene. The time should only be spent to deal with the things you have listed on next slide and should still be kep to a minimum. We are not good keepers of time while we are caring for patients.
69 1,199 Cardiac Arrests ROSC in 27.4% Rearrest in 36% Time to rearrest Median 3.1 min ( )
70 Post-Resuscitation Care Focus should be on restoring perfusionPerfuse the myocardiumPerfuse the brainFluids and pressors for MAP >90Remove the ITDInitiate hypothermiaObtain 12 lead EKGTHEN move the patient
72 Barriers in Post-Cardiac Arrest Care Post– cardiac arrest patients are treated by multiple teams of providersVariation in post-cardiac arrest treatment and patient outcome between institutions.Limited reliability of early prognostication (<72 hours after arrest)
73 The science behind the cooling Han Solo frozen in Carbonite – Star Wars Episode V (1980)
76 ILCOR Advisory Statement On the strength of these studies, the International Liaison Committee on Resuscitation published recommendations supporting the use of induced hypothermia after resuscitation from cardiac arrest. Given the large numbers of patients suffering cardiac arrest each year, even a small impact in survival and favorable neurologic outcome would lead to important gains for thousands of patients.Unconscious adult patients with ROSC after out-of-hospital VF cardiac arrest should be cooled to 32°C - 34°C for hoursPossible benefit for other rhythms or in-hospital cardiac arrest
77 Editorial Comments“The reason hypothermia has not become the standard of care for post-resuscitation is simple. Emergency and EMS physicians have failed to make it so.”Mennegazzi and Callaway, PEC 2005
78 “The Future” 720j Defibrillation? Hands on Defibrillation? Intra-arrest cooling?Mechanical CPR and AC/DC CPR?Regional Receiving Facilities?
79 Knowledge Gaps Impact of Prehospital Cooling in Outcomes? Continuous temperature in the Field?Rate of Cooling?Target? How Long?Urban vs. Rural EMS?ALS Vs BLS?How do we train Providers?
80 Take Home Message Resuscitation is not over with ROSC Post-Cardiac Arrest Patients need to be treated with a high sense of urgency.Patients should receive hypothermia specially if initial rhythm was VF/VT.Hypothermia is not a substitute for other key components in the Chain of Survival
81 Take Home MessagePost-resuscitation/cardiac specialty hospitals should receive patients directly from the field or in prompt transferCoordination between EMS, EM, ICU, and Cardiology is a must!!Engage all stakeholders in your systemManagement of Cardiac Arrest is evolving rapidly!! EMS Medical Directors must keep up
84 Jose G. Cabanas MD, MPH / Brent Myers MD, MPH Wake County EMS System Out-of-Hospital Initiation of Therapeutic Hypothermia with Cold Saline Improves Survival in Patients with Return of Spontaneous Circulation in the Field.Jose G. Cabanas MD, MPH / Brent Myers MD, MPHWake County EMS System
85 Authors Brent Myers MD, MPH, Wake EMS/WakeMed Jose G. Cabanas, MD, Wake EMS/WakeMedRyan Lewis, MS, EMT-P, Wake EMSValerie De Maio, MD MSc, WakeMedGraham Synder, MD, WakeMedGay Beneveides, MD, WakeMedRobert Denton, MD, Rex HealthcareDaniel Licastese, RN, Rex HealthcareRobert Lee, MS MA, WakeMed
86 DisclosureThis Project was supported by the SAEMS EMS Physio-Control Award (2008)
87 ObjectiveTo determine the impact on survival of a standard post-resuscitation care protocol that includes prehospital initiation of therapeutic hypothermia in patients with return of spontaneous circulation (ROSC) in the field.
88 Methods Observational cohort “Before and after” – Introduction of Therapeutic Hypothermia for patients with prehospital ROSCPost-resuscitation patients are selectively transported to one of 2 high volume PCI centersWake County NC - pop. 897,000April 2005 through December 2008
89 Cardiac Arrest Response All calls receive EMD from a single, high-volume centerFire first response with AED and compressionsParamedic response with transport ambulances (2)Supervisory response at paramedic level
91 Criteria for Induced Hypothermia ROSC after cardiac arrest not related to trauma or hemorrhageAge 16 years or greaterFemale without obviously gravid uterusInitial temperature >34 CPatient with advanced airway (no RSI)Patient remains comatose without purposeful response to pain
92 Data CollectionAll EMS records are maintained in an electronic databaseRecords with any of the following characteristics are reviewed to determine if cardiac arrest occurred:EMS Patient Disposition = cardiac arrestCPR procedure is recordedDefibrillation is recordedInduced Hypothermia Procedure
93 Inclusion CriteriaAll adult patients resuscitated from out of hospital cardiac arrest (OHCA) prior to hospital arrival, regardless of initial rhythm, were included if they had ROSC in the field.
94 Exclusion Criteria Age less than 16 Obvious traumatic origin of arrest EMS witnessed arrestArrest not in EMS controlPrison facilitiesOut-of-system interceptArrests under direction of non-EMS physician
95 Outcome Measures Discharge from hospital (primary) Neurologically intact survival was defined as CPC 1 or 2 at time of hospital discharge.2 blinded physician reviewers from each hospital independently assigned CPC scores based on patient discharge records
96 Included Patients / Phase All PhasesN=640Before (17 Months)227After (26 Months)413
97 Patient and EMS Characteristics Before After(n=227) (n=413)Mean age (yrs)6664Male sex62%60%Bystander witnessed arrest45%32%Bystander CPR38%39%Mean Response (mins)5.6Initial rhythm VF/VT35%NOTE: no statistically significant difference between study periods
99 Survival to Hospital Discharge for All Rhythms NOTE: statistically significant difference p value <0.0163
100 Survival to Hospital Discharge for All Rhythms *Difference in overall survival was significant with a p-value of
101 Percent of Survivors Neurologically Intact NOTE: no statistically significant difference between study periods
102 LimitationsProtocol-driven pre- and post-resuscitation cardiac arrest careHawthorne effectIntention-to-treat analysis
103 ConclusionOut-of-hospital standard post-resuscitation care protocol that includes induced hypothermia for all patients with ROSC significantly improved survival to hospital discharge in this EMS system
105 Wake County EMS Annually 70,000+ 911 calls (700 OHCA) Providers: 1,500 BLS, 225 ALS, 17 APPsTiered response incl. dispatch assisted CPR, first responder apparatus and paramedic supervisor to high acuity callsServe 7 hospitals of 3 health care systems, incl. 2 PCI capable facilitiesAnnual protocol updates in AprilUtstein style data collection template
106 Survival to Discharge – VF/VT NOTE: no statistically significant difference between study periods
107 Optimizing Neurologic Resuscitation Mild Induced Hypothermia (IH)Decrease metabolic demand4,5,6,7Inhibits inflammatory cascade12,14,15IH is time sensitive8,11,14,15Hemodilution12,13Normal saline dilution as part of hypertensive reperfusion strategyHypertensive reperfusionUse of vasopressors to target MAP of 90Key characteristic of the post resuscitation syndrome is loss of cerebral autoregulaion. Healthy brain maintains global CBF of 50 mL per 100g of brain tissue per minute within a cerebral perfusion pressure range of mmHg. When cerebral perfusion pressure drops below 50 mmHg there is reduced flow. Brain may be able to tolerate CBF of as low as 10% of normal but trickle flow <10% may be worse than no flow.(see persse for description.)Induced hypothermia appears to be time sensitive. In rat studies delays > 45 min resulted in loss of benefit. (Markarian GZ, et al. Mild hypothermia:therapeutic window after experimental cerebral ischemia. Neurosurgery 1996, 38: ) In dogs delaying hypothermia by 15 minutes obscured the benefit in functional outcome as compared with that with immediate hypothermia. (Kuboyama)
114 So if compressions are the MOST important intervention for a successful resuscitation what is our airway management device of choice in a cardiac arrest? ….more on this later
115 Ventilation vs Oxygenation Oxygenation is delivery of oxygen to RBC and tissuesOxygenation determined by two things:FiO2 (% inspired O2)Pressure of gas (CPAP or PEEP)Ventilation is the elimination of CO2Ventilation is determined by two things:Tidal volumeVentilatory rate
116 Why is this important? Cells require oxygen to make energy Inability to oxygenate the tissue is quickly fatalExchanging carbon dioxide is NOT!If forced to make the choice between oxygenation and CO2 exchangeCHOOSE OXYGENATION!
117 So why does that matter?If oxygenation has nothing to do with ventilation why do we ventilate patients at rates > 30 breaths per minute?Who cares…..if breathing 12 times a minute is good 30 times a minute MUST be better right?
118 ….what is our airway management device of choice in a cardiac arrest?
119 The device that allows us to oxygenate the patients brain and myocardium and causes the… LEAST interruption in compressions
120 Objective Describe the importance of: Prehospital resuscitationContinuous compressionControlled ventilatory ratesDescribe the value and limitations of advanced airway management adjunctsList the critical components of cardiac arrest management
121 Pit Crew CPRWent to simulation to design highly scripted process that allows intervention without interruptionTasks assigned to positions rather than individuals because individuals change
122 OOHCA What matters! For first 2 cycles concentrate on compressions Get on the chest as quick as possibleCompress hard and fast (do NOT exceed 120)Minimize interruptionsIf on monitor compress up to delivery of shockResume compressions immediately regardless of pulse or rhythmBVM ONLYControl ventilation (use your blinky light)
123 OOHCA What matters! After 2 cycles (4 min) place King Airway Don’t stop compressions!ETI only if unsuccessful with BIADPlace gastric tube via KING or OG/NGControl your ventilationsRecheck tube with each patient movement
124 OOHCA What matters! Continue resuscitation Rhythm/Pulse check only at 2 minChange compressor q 1 min regardless of fatigueRun checklist to assure overlooked errorsCareful consideration of causesDo NOT move the patient unless:You are in potential dangerYou are in a public placeOther situation not suitable to leave the body
125 Pre-hospital providers must be the experts in cardiac arrest resuscitation!
126 What we know? Metabolic Phase 2 4 6 8 10 12 14 16 18 20 Electric 2468101214161820Arrest Time (min)SHOCKCCCHYPO?ElectricCirculatory PhaseEtapa metabólicaMetabolic Phase
128 Inertia….. it’s not just for cars anymore! Blood Inertia?Berg et al. Resuscitation 2001
129 What is Post-Cardiac Arrest Syndrome? Unique / complex combination of pathophysiological processes, which include:Post–cardiac arrest brain injury,Post–cardiac arrest myocardial dysfunctionSystemic ischemia/reperfusion response.DON’T FORGET!! the unresolved pathological process that caused the cardiac arrest.
130 Post-Cardiac Arrest Syndrome High mortality of cardiac arrest patients after ROSC is due to multiple organ system dysfunctionCardiac Arrest etiologyDuration of cardiac arrest and no flowReperfusion injury after ROSCHigh mortality in post-cardiac arrest is related to MOSF – Especially cardiovascular and neurological collapse (brain injury)
131 Post-Cardiac Arrest Brain Injury PathophysiologyImpaired Cerebral AutoregulationCerebral EdemaClinical ManifestationsComa, Seizures, MyoclonusVegetative State, Brain Death, StrokesPotential TreatmentsTherapeutic HypothermiaEarly Hemodynamic OptimizationVentilation/ OxygenationI don’t think airway is the best term. Shouldn’t this be ventilation / oxygenation?
132 Did Rate Change with Feedback? Independent Variables (Not Paired)SceneKruskal-Wallis TestP = 0.25TransportP = 0.39*Independent groups and not paired – so use Kruskal Wallis Test (non-parametric)
134 Systemic Ischemia/ Reperfusion Response PathophysiologySystemic Inflammatory ResponseIncreased CoagulationAdrenal SuppressionKey Potential TreatmentsTemperature ControlHemodynamic OptimizationGlucose ControlTreat Cause of Arrest
135 Aha statement Post-Resuscitation Recommendations Induced hypothermia Prevention of hyperthermiaTight glucose controlPrevent hypocapniaMaintain elevated MAP
136 Therapeutic Hypothermia The protective effects of hypothermia induction have been suggested since the time of Hippocrates, who advocated packing bleeding patients in snow.Baron Larrey, Napoleon’s Battle surgeon during the invasion of Russia had noted that soldiers that were left in the snow had improved survival than those treated with blankets and warm drinks.
137 History of Hypothermia and Cardiac Arrest Williams et al -Annals of Surgery, Volume 4 #3 September 1958
138 Why Induced Hypothermia? Pre-hospital ROSC145%(38%) of v-fib arrests37% (22%)of all cardiac arrestsDischarge112%(10%)Post Resuscitation Deaths310% die due to recurrent dysrhythmias30% die to due to cardiovascular collapse40% die due to PRE
139 Mechanisms of Hypothermia In the normal brain, hypothermia reduces the cerebral metabolic rate for oxygen (CMRO2) by 6% for every 1°C reduction in brain temperatureIt is thought to suppress many of the chemical reactions associated with reperfusion injury. (free radical, excitatory amino acid release, and calcium shifts, which can in turn lead to mitochondrial damage and apoptosisSteen PA, Newberg L, Milde JH, et al. Hypothermia and barbiturates: individual and combined effects on canine cerebral oxygen consumption. Anesthesiology. 1983;58:527–532.
140 Post Resuscitation Encephalopathy Initial insult from cardiac arrestPeriod of luxuriant hyperperfusion3Cell injury8,11Oxygen free radical formationInflammatory cascadeGlutamate mediated cell deathLoss of autoregulationSludging and hypoperfusion3,8,11Perfusion/demand mismatch8,11PRE 38%; recalcitrant ventricular dysrhythmias 10%; continued low cardiac output states 31%) see myerburg for best review of pathInflammatory cascade: ischemia causes outpouring of excitotoxic glutimate which in turn activates nmda and ampa receptors. This causes calcium and sodium channels open initiating enzymatic induced neuronal death. Particularly vulnerable are the hippocampus, cerebellum, frontoparietal cortex and basal ganglia. Cerebral perfusion problems occur in 4 phases.(see persse,D Manging the post reuscitation patient in the field for the review) 1. Multifocal no reflow occurs immediately and seems to be readily overcome by normotensive or hypertensive reperfusion. 2. Transient global reactive hyperemia lasting minutes. 3. Delayed, prolonged global and multifocal hypoperfusion begins about two hrs after circulation is restored leading to a decrease in blood flow of up to 50% because of loss of autoregulation. Meanwhile cerebral oxygen consumption returns to baseline or above baseline values leading to mismatch of oxygen delivery and uptake. 4. late resolution is the return to normal ccbf and consumption or in the case of brain death the abnormal flow and consumption persist. Note sludging of the blood contributes to the no-reflow phenomenon. Hemodilution has been shown to be effective in increasing cerebral blood flow.After initial period of hyperemia the dysregulation results in CBF as low as 50% of normal while cerebral metabolic ocygen consumption returns to or above baseline creating a mismatch of ocygen delivery and uptake(persse)
142 ObjectiveTo determine the impact on survival of a standard post-resuscitation care protocol that includes prehospital initiation of therapeutic hypothermia in patients with return of spontaneous circulation (ROSC) in the field.
143 Methods Observational cohort “Before and after” – Introduction of Therapeutic Hypothermia for patients with prehospital ROSCPost-resuscitation patients are selectively transported to one of 2 high volume PCI centersWake County NC - pop. 897,000April 2005 through December 2008
144 Cardiac Arrest Response All calls receive EMD from a single, high-volume centerFire first response with AED and compressionsParamedic response with transport ambulances (2)Supervisory response at paramedic level
146 Criteria for Induced Hypothermia ROSC after cardiac arrest not related to trauma or hemorrhageAge 16 years or greaterFemale without obviously gravid uterusInitial temperature >34 CPatient with advanced airway (no RSI)Patient remains comatose without purposeful response to pain
147 Data CollectionAll EMS records are maintained in an electronic databaseRecords with any of the following characteristics are reviewed to determine if cardiac arrest occurred:EMS Patient Disposition = cardiac arrestCPR procedure is recordedDefibrillation is recordedInduced Hypothermia Procedure
148 Inclusion CriteriaAll adult patients resuscitated from out of hospital cardiac arrest (OHCA) prior to hospital arrival, regardless of initial rhythm, were included if they had ROSC in the field.
149 Exclusion Criteria Age less than 16 Obvious traumatic origin of arrest EMS witnessed arrestArrest not in EMS controlPrison facilitiesOut-of-system interceptArrests under direction of non-EMS physician
150 Outcome Measures Discharge from hospital (primary) Neurologically intact survival was defined as CPC 1 or 2 at time of hospital discharge.2 blinded physician reviewers from each hospital independently assigned CPC scores based on patient discharge records
151 Included Patients / Phase All PhasesN=640Before (17 Months)227After (26 Months)413
152 Patient and EMS Characteristics Before After(n=227) (n=413)Mean age (yrs)6664Male sex62%60%Bystander witnessed arrest45%32%Bystander CPR38%39%Mean Response (mins)5.6Initial rhythm VF/VT35%NOTE: no statistically significant difference between study periods
153 Survival to Hospital Discharge for All Rhythms NOTE: statistically significant difference p value <0.0163
154 Survival to Hospital Discharge for All Rhythms *Difference in overall survival was significant with a p-value of
155 Percent of Survivors Neurologically Intact NOTE: no statistically significant difference between study periods
156 LimitationsProtocol-driven pre- and post-resuscitation cardiac arrest careHawthorne effectIntention-to-treat analysis
157 ConclusionOut-of-hospital standard post-resuscitation care protocol that includes induced hypothermia for all patients with ROSC significantly improved survival to hospital discharge in this EMS system
158 Optimizing Neurologic Resuscitation Mild Induced Hypothermia (IH)Decrease metabolic demand4,5,6,7Inhibits inflammatory cascade12,14,15IH is time sensitive8,11,14,15Hemodilution12,13Normal saline dilution as part of hypertensive reperfusion strategyHypertensive reperfusionUse of vasopressors to target MAP of 90Key characteristic of the post resuscitation syndrome is loss of cerebral autoregulaion. Healthy brain maintains global CBF of 50 mL per 100g of brain tissue per minute within a cerebral perfusion pressure range of mmHg. When cerebral perfusion pressure drops below 50 mmHg there is reduced flow. Brain may be able to tolerate CBF of as low as 10% of normal but trickle flow <10% may be worse than no flow.(see persse for description.)Induced hypothermia appears to be time sensitive. In rat studies delays > 45 min resulted in loss of benefit. (Markarian GZ, et al. Mild hypothermia:therapeutic window after experimental cerebral ischemia. Neurosurgery 1996, 38: ) In dogs delaying hypothermia by 15 minutes obscured the benefit in functional outcome as compared with that with immediate hypothermia. (Kuboyama)
159 Is Earlier Better?? Nordmark 2005 20 Pigs Subjected to 8 minutes of V-fib followed by CPRRandomized into 2 groups (hypothermia/control)Hypothermic group received cold saline after 1 min in CPRConclusion: “Inducing Therapeutic Hypothermia with a cold infusion seems to be an effective method that can be started during ongoing CPR”
160 Is Earlier Better?? Bernard 2008 Resuscitation 60 year-old female in cardiac arrest (37 minutes) due to pericardial tamponadeD/H Alert and OrientedConclusion: “Treatment with a rapid Intravenous Infusion of large volume (40ml/kg), Ice-cold (4˚C) fluid during CPR induces mild hypothermia and may provide neurological protection”
161 Is Pre-Hospital Cooling Safe?? Bruel2008The study was aimed to determine the safety and effectiveness of cooling patients while in ALS SupportThe Median time to reach mil hypothermia (<34˚C) after ROSC was 16 minutesConclusion: “The infusion of 2 liters of Normal Saline at 4˚C in the field during ALS to induce mild hypothermia in resuscitated OHCA patients is safe, feasible and effective”
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