How EMS can improve the long term outcomes for resuscitated patients

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Induced Hypothermia

• How EMS can improve the long term outcomes for
  resuscitated patients

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Wake EMS Induced Hypothermia Team

• J. Brent Myers, MD, MPH
• Medical Director
• Paul R. Hinchey, MD, MBA, EMT-P
• Assistant Medical Director
• Joseph Zalkin, EMT-P
• Assistant Chief Professional Development
• Jon Olson, MBA, MHA, EMT-P
• District Chief Operations
• Ryan Lewis, EMT-P
• District Chief Quality Assurance
• Donald Garner, EMT-P
• District Chief Training

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Induced Hypothermia(IH)

• What is Induced Hypothermia?
• Why IH at Wake EMS?
• How does it work?
• When is it indicated?
• How will it be applied?

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What is Hypothermia?

• Mild Hypothermia
• 89.6-95F (32-35C)
• Moderate hypothermia
• 82.4-89.5F (28-32C)
• Severe Hypothermia
• lt82.4F(28C)

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What is Induced Hypothermia?

• Active cooling of the body to below normal levels
  

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So why would you intentionally induce hypothermia?
a little history will help..

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• In March of 2005, nine months prior to the
  November 2005 release of the AHA resuscitation
  guidelines, Wake County EMS System implemented
  new CPR protocols using the latest in
  resuscitation techniques and available technology.

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The Technique

• Changed CPR
• Emphasis on effective uninterrupted compression
• Decreased emphasis on importance of ventilation
• Slower ventilatory rates

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The Technology

• Use of ETCO2
• As confirmation of ETT placement
• Goal directed respiratory rate

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The Technology

• EZ IO drill
• Rapid IV access if initial IV attempt fails

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So. what happened?
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What does that have to do with hypothermia?
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Dramatic Improvement?

• Impact on Pre-hospital ROSC1
• From 22 to 37 of all cardiac arrests
• From 38 to 45 of v-fib arrests
• From 40 to 53 of witnessed v-fib arrests

• Impact on discharge from hospital1
• From 10 to 12

Not really what we expected
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So why the disparity?

• Post Resuscitation Deaths3
• Refractory dysrhythmias (10)
• Low cardiac output states (30)
• Post Resuscitation Encephalopathy (40)

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Post Resuscitation Encephalopathy (PRE) is the
single largest contributor to post resuscitation
deaths and poor neurologic outcomes.
PRE is caused by a series of events that begin
immediately following reperfusion of the brain
with ROSC
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PRE

• Initial hypoperfusion insult followed by period
  of hyperperfusion with ROSC3
• Cell injury8,11
• Oxygen free radical formation
• Inflammatory cascade
• Glutamate mediated cell death
• Loss of Autoregulation3,8,11
• Patchy intracerebral vasoconstriction
• Intravascular sludging and hypoperfusion
• Perfusion/demand mismatch

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Luxuriant Hyperperfusion
ROSC
Unregulated blood flow leads to oxygen free
radical formation and cell injury. It triggers
inflammation, glutamate mediated cell death and
edema.
Initial restoration of blood flow results in
unregulated perfusion of the brain. This period
is referred to as the luxuriant hyperperfusion
period and can last from 10-30 minutes.
The post resuscitation brain develops diffuse,
patchy vasoconstriction and intravascular
sludging.
Vasoconstriction leads to supply demand mismatch
which leads to hypoperfusion and cell damage
which perpetuates the inflamatory response.
Inflammatory Response
Supply Demand Mismatch
Loss of Autoregulation
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Factors in PRE

• Inflammation and Edema
• Vasoconstriction and Sludging
• Supply Demand Mismatch

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Induced hypothermia is part of a multifaceted
approach to optimizing neurologic resuscitation.
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Optimizing Neurologic Resuscitation

• Mild Induced Hypothermia (IH)
• Inhibits inflammatory cascade12,14,15
• IH is time sensitive8,11,14,15
• Animal studies demonstrate time dependent benefit
• Decrease metabolic demand4,5,6,7
• 5-7 decrease in metabolic demand for each degree
  Celsius

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Optimizing Neurologic Resuscitation

• Hypertensive reperfusion12,13,14,15
• Forced perfusion despite vasoconstriction
• Vasopressors to target MAP of 90-100mmHg
• Hemodilution12,13
• Normal saline dilution as part of hypertensive
  reperfusion strategy
• Reduces vascular sludging
• Cold saline as a rapid cooling technique

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There are several landmark studies on the subject
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Holzer completed a metaanalysis of a few of the
studies
Hypothermic Normothermic
Alive at 6 months with favorable neurologic status 55 (75/136) 39 (54/137)
The largest is the HACA study
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Summary of Studies
Neurologic 50 vs 14
Neurologic 23 vs 7
Survival 50 vs 23
Survival 54 vs 33
Neurologic 49 vs 26
Neurologic 55 vs 39
Survival 48 vs 32
Survival 59 vs 45
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Metaanalysis21

• Short-term Benefit Ratio
• 1.6895 CI 1.29-2.07
• 6 Month Benefit Ratio
• 1.44 95 CI 1.11-1.76
• Number needed to treat (NNT)
• 6 patients CI (4-13)

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Some familiar NNT
The analysis of the studies and the limited side
effect profile led to several organizations
making recommendations on post resuscitation
hypothermia
Cath capable facility versus thrombolytics
Aspirin therapy for MI
Beta Blocker therapy for MI
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ILCOR Advisory Statement

• Unconscious adult patients with ROSC after
  out-of-hospital VF cardiac arrest should be
  cooled to 32C - 34C for 12 - 24 hrs.
• Possible benefit for other rhythms or in-hospital
  cardiac arrest

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Aha statement

• Post Resuscitation Treatment
• Induced hypothermia
• Prevention of hyperthermia
• Tight glucose control
• Prevent hypocapnia
• Maintain elevated MAP

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As part of the effort to reduce the disparity
between our resuscitation rates and hospital
discharge rates, Wake County EMS System began
looking at the use of induced hypothermia in
August of 2005.
First we had to look at the effects of
hypothermia..
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Effects of IH

• Holzer Bernard4,21
• No statistically significant difference in
  complication rates in normothermic and
  hypothermic cohorts
• Potassium shifts
• Intracellular shift with induction
• Extracellular shift with warming
• Managed with replacement and gradual rewarming
• Fluid status
• Cooling causes diuresis
• Warming causes hypovolemia
• Requires careful monitoring of urine output and
  fluid status

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Effects of IH

• Respiratory Alkalosis
• Temperature corrected ABG allows changes in
  minute ventilation to support normal PaCO2
• Hyperglycemia
• HACA group and Bernard found that high blood
  glucose after cardiac arrest is associated with
  poor neurologic outcomes but did not find any
  improvement with tight glucose controls. 4,5

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Complications of IH in Other Applications

• Neutropenia
• Neutropenia and increased incidence of pneumonia
  seen in patients exposed to prolonged hypothermia
  (gt24hrs) in other applications
• Coagulopathy18,19,20
• May alter clotting cascade, platelet function
• Cardiac dysrhythmias
• Little risk for clinically significant
  dysrhythmias if temperatures are maintained
  gt30C17

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After finding limited side effects we developed a
comprehensive protocol from field implementation
to hospital discharge.
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Wake County Plan

• Objective is cost effective, prehospital
  initiation of induced hypothermia in patients
  with ROSC.

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Wake County Plan

• Criteria for Induced Hypothermia

Return of Spontaneous Circulation
Remains Comatose
Confirmed Intubation
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Wake County Plan

• Criteria for Induced Hypothermia

Return of Spontaneous Circulation

• Palpable Pulses
• Auscultatable Blood Pressure
• Non-Traumatic Event

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Wake County Plan

• Criteria for Induced Hypothermia

Return of Spontaneous Circulation
Remains Comatose

• No purposeful movements

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Wake County Plan

• Criteria for Induced Hypothermia

Return of Spontaneous Circulation
Remains Comatose
Confirmed Intubation

• Auscultated Breath Sounds

• Tube Check Device

• ETCO2 Reading

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Wake County Plan

• Criteria for Induced Hypothermia

Return of Spontaneous Circulation
Remains Comatose
Confirmed Intubation
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Wake County Plan

• Protocol for Induced Hypothermia

Expose the Patient
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Wake County Plan

• Protocol for Induced Hypothermia

Slowly administer Versed 0.15mg/kg up to 10mg
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Wake County Plan

• Protocol for Induced Hypothermia

Administer Vecuronium 0.1mg/kg to max of 10mg
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Wake County Plan

• Protocol for Induced Hypothermia

Apply Ice Packs Neck Axilla Groin
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Wake County Plan

• Protocol for Induced Hypothermia

Cold Saline Infusion 30ml/kg to max of 2 Liters
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Wake County Plan

• Protocol for Induced Hypothermia

Administer Dopamine 10-20 mcg/kg/min
Attain a MAP of 90-100
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Wake County Plan

• Pearls of Induced Hypothermia

• Be mindful when exposing the patient

• Do not delay transport to cool

• Constantly reassess airway patency

• Do not hyperventilate the patient

• If loss of ROSC, discontinue cooling and treat
  per appropriate protocol

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Protocol Review
NOTE If the patient does not meet criteria for
IH or if the patient can not be intubated with an
endotracheal tube, a LMA is placed and the
patient is managed by standard post-resuscitation
protocols.

• Arrest not due to hemorrhage or trauma
• Age gt 16
• Remains comatose with no purposeful response to
  pain
• Patient is intubated

ROSC
Initial tympanic temperature criteria is used to
avoid potential overshoot of the target range
Criteria for Induced Hypothermia and Initial
Temp of gt34C
Post-Resuscitation Protocol
NO
ETCO2 gt 20mmHg is used both to confirm tube
placement and as an additional measure of
successful ROSC. It is unlikely that an
appropriately ventilated patient with ROSC will
have an ETCO2 lt 20mmHg.
YES
Neuro exam consists of basic evaluation of pupil
response and motor response to pain
ET Tube Placed and ETCO2 gt20mmHg
Intubation Protocol
NO
YES
Perform Neuro Exam and Document Start Hypothermia
Procedure
Intubated
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Protocol Review
Perform Neuro Exam and Document Start Hypothermia
Procedure
Vecuronium is used as a long acting paralytic to
prevent shivering. It is NOT used to facilitate
intubation. If the patient can not be intubated
they are excluded from pre-hospital hypothermia
therapy.
Versed is used as a sedative in conjunction with
the paralytic.
Expose patient Apply Ice Packs to Axilla and Groin
Versed 0.15mg/kg up to 10mg max dose
Chemical ice packs are used for external cooling.
Misting or wetting the patient can be used in
conjunction with ice packs to expedite the
cooling process.
Vecuronium 0.1mg/kg up to 10mg max dose
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Protocol Review
Cold Saline Bolus 30ml/kg up to 2 Liters
Dopamine 10-20mcg/kg/min to achieve MAP of 90 to
100
Cold saline (2-4C) is infused as part of the
internal cooling process. While this may seem
like a large fluid bolus studies have shown that
the core temperature can be reduced 1-2C without
adverse side effects from the fluid. This fluid
volume is also necessary for the hypertensive
reperfusion component of the therapy and to
compensate for the diuresis that occurs with
cooling.
Dopamine is used as needed to maintain mean
arterial pressures (MAP) sufficient to perfuse
the brain. Fortunately most new monitors
calculate the MAP for you. (MAP DBP 1/3SBP
DBP)
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Seem like a lot to remember?
So Ryan Lewis created checklists to reduce errors
and expedite initiation
We thought so
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Managing Cold Saline

• Keeping it cold enough to be effective

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Managing Cold Saline

• 36-39F (2-4 C)
• is the target temperature

The big question was...
how to keep it there?
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Managing Cold Saline

Model 15 Freezer 14qt Capacity 27 pounds 0 40
Degrees Fahrenheit 3.9 Amp Draw on 12V
System Fits neatly in floorboard of SUV Approx
400 retail
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Managing Cold Saline

• Initial Deployment on EMS District
  Chief Vehicles

which respond to all cardiac arrests
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Managing Cold Saline

• Initial Deployment on EMS
  District Chief Vehicles

Reduces initial start up costs
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Managing Cold Saline

• Maintaining stock in refrigerator in Station at
  45 degrees
• 6 Liters in 12V freezer units on select response
  units
• Add 12V freezers to all system ambulances as
  budget permits

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Maintaining Hypothermia
once at the hospital
Thermal regulation with an endovascular cooling
device
reduces workload and maintains tight temperature
control.
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Endovascular Device
Placed directly into the Inferior Vena Cava
Circulates temperature controlled saline through
the catheter module Monitors temperature to
within 0.1-0.3 C of pulmonary artery temp Used
for both cooling and rewarming
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Is this Research?

• Current AHA resuscitation guidelines are based on
  prospective randomized trials
• We felt it was unethical to conduct a randomized
  trial with a treatment that is now recommended
  care
• Current Wake EMS IH protocol represents a change
  in therapy to meet the new standard of care.

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Future Research?

• Will evaluate efficacy with historical case
  control based on prior resuscitation and
  discharge rates.
• Currently there is no data on pre-hospital
  application of IH therapy
• Evaluate effectiveness of saline induced cooling
  process
• Evaluate prehospital application

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How do you track patient outcomes from
pre-hospital care through to discharge without
losing them in follow-up?
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EMS Banding System

• Developed by Joseph Zalkin the system provides
  unique EMS ID
• ID is scanned into EMS electronic call report AND
  hospital electronic chart
• Provides unique tracking number throughout
  admission to discharge

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What other steps are we taking to improve
survival?

• Introduction of endotracheal introducer (Bougie)
• Res-Q-Pod

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Why do we do all this?

• EMS is unique medical practice environment whose
  impact extends beyond arrival at the ED doors
• In cardiac arrest our goal is discharge to home
• Less than 50 of ROSC are sent home
• Hospitals currently utilizing IH
• IH improves long term outcome
• IH is time dependent
• IH is cost effective
• EMS drives hospital implementation

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Summary

• IH is part of multifaceted AHA recommended
  strategy to improve neurologic outcomes in CA
• It requires limited training, minimal cost of
  implementation and has few significant
  complications
• IH is ideally suited to EMS because it
• Impacts outcomes
• Is time sensitive
• Is cost effective

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This Just In!
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• 109 out of hospital cardiac arrest from all
  rhythms
• Retrospective study using historical controls
• 55 induced hypothermia and 54 controls
• Hypothermia to 33deg C with external device for
  24 hrs
• Patients treated with versed, fentanyl and
  vecuronium
• MAP were maintained 90-100mmHg

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• Survey of 2,248 physicians in UK, US and Finland
• Emergency, Cardiology, and Critical Care
  Physicians
• 74 of US and 64 of Non-US never used
  hypothermia
• 16 of US ED physicians and 34 of US
  Intensivists
• Reasons cited
• Not enough data
• Not a part of ACLS guidelines
• Too technically difficult to use

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Citations

1. Wake County EMS Database
2. Edgren, E et al Assessment of neurological
   prognosis of comatose survivors of cardiac
   arrest. Lancet 1994 3431055-59.
3. Myerburg, R et al. Clinical, electrophysiologic
   and hemodynamic profile of patients resuscitated
   from prehospital cardiac arrest. Am J Med. 1980
   68568-76.
4. Hypothermia After Cardiac Arrest (HACA) Study
   Group. Mild therapeutic hypothermia to improve
   the neurologic outcome after cardiac arrest. N
   Engl J Med. 2002 346549-56.
5. Bernard, SA et al. Treatment of comatose
   survivors of out of hospital cardiac arrest with
   induced hypothermia. N Engl J Med. 2002
   346557-63.
6. Yanagawa, Y, et al. Preliminary clinical outcome
   study of mild resuscitative hypothermia after out
   of hospital cardiopulmonary arrest.
   Resuscitation 1998 3661-66.
7. Bernard, SA, et al. Clinical trial of induced
   hypothermia in comatose survivors of out of
   hospital cardiac arrest. Ann Emerg Med.
   199730146-53.
8. Persse, DE et al. Managing the
   post-resuscitation patient in the field. PEC
   20026114-22.
9. Part 7.5 Postresuscitation Support. Circulation
   200511284-88.
10. Kollmar, R. Early effects of acid-base
    management during hypothermia on cerebral infarct
    volume, edema, and cerebral blood flow in acure
    focal cerebral ischemia in rats. Anesthesiology
    200297868-74.
11. Persse, D. Et al. Managing the post
    resuscitation patient in the field. PEC
    20026114-122
12. Leonov Y, et al. Hypertension with hemodilution
    prevents multifocal cerebral hypoperfusion after
    cardiac arrest in dogs. Stroke. 19922345-53.
13. Sterz F, et al. Hypertension with or without
    hemodilution after cardiac arrest in dogs.
    Stroke. 1990211178-84.
14. Kuboyama K, et al. Delay in cooling negates
    beneficial effects of mild resuscitative
    hypothermia after cardiac arrest in dogs. Crit
    Care Med. 1993211348-58.
15. Markarian GZ, et al. Mild hypothermiatherapeutic
    window after experimental cerebral ischemia.
    Neurosurgery 1996, 38542-551.
16. Nolan, JP. Therapeutic hypothermia after cardiac
    arrest An advisory statement by the advanced
    life support task force of the international
    liaison committee on resuscitation. Circulation
    2003108118-121.
17. Danzl DF. Accidental hypothermia. N Engl J Med.
    19943311756-60.
18. Patt, A. Effect of hypothermia induced
    coagulopathies in trauma. Surg Lcin North Am.
    198868775-85.
19. Roher MJ. Effect of hypothermia on the
    coagulation cascade. Crit Care Med. 1992 20
    1402-05.

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For More Information

• Paul Hinchey
• paul.hinchey_at_co.wake.nc.us
• Jonathan Olson
• jolson_at_co.wake.nc.us