Therapeutic Hypothermia for Therapeutic Hypothermia for Post-Cardiac Arrest PatientsPost-Cardiac Arrest Patients

Lois K. Andrews, RN-BC, MS, CCRNApril 3, 2011

1.1. Review the historical background of hypothermia use in Review the historical background of hypothermia use in medicine.medicine.

2.2. Describe the physiologic effects of hypothermia. Describe the physiologic effects of hypothermia.

3.3. Identify the indications for hypothermia after cardiac arrest.Identify the indications for hypothermia after cardiac arrest.

4.4. Identify the contraindications for instituting the hypothermia Identify the contraindications for instituting the hypothermia protocol.protocol.

5.5. Describe the patient care required during cooling and Describe the patient care required during cooling and rewarming.rewarming.

ObjectivesObjectives

The ProblemThe Problem

310,000 experience sudden cardiac death 310,000 experience sudden cardiac death in the US yearlyin the US yearly

265,100 EMS-treated out of hospital 265,100 EMS-treated out of hospital cardiac arrests in the UScardiac arrests in the US

40% of those resuscitated have ROSC40% of those resuscitated have ROSC Survival to discharge of OHCA 25 - 40%Survival to discharge of OHCA 25 - 40% Less than 10% of survivors regain former Less than 10% of survivors regain former

lifestyleslifestyles

Historical Background Historical Background InformationInformation

2002 Studies2002 Studies

Stringent inclusion criteria – VF/VTStringent inclusion criteria – VF/VT Fewer deaths & disability in both studiesFewer deaths & disability in both studies 6 month mortality decreased from 55% to 6 month mortality decreased from 55% to

41% in European study, NNT = 641% in European study, NNT = 6 In Australian study, mortality decreased In Australian study, mortality decreased

from 68% to 51% and 49% of survivors from 68% to 51% and 49% of survivors were reported to have a favorable were reported to have a favorable neurological outcomeneurological outcome

2005 Recommendation2005 RecommendationAHA & ILCORAHA & ILCOR

Recommended inducing & maintaining for Recommended inducing & maintaining for 12 to 24 hours, Therapeutic hypothermia 12 to 24 hours, Therapeutic hypothermia (33°C) after ROSC in patients (33°C) after ROSC in patients experiencing OHCA who remain comatose experiencing OHCA who remain comatose hours of after resuscitation & in whom the hours of after resuscitation & in whom the initial cardiac rhythm is VF.initial cardiac rhythm is VF.

2010 International Consensus2010 International Consensus

Therapeutic hypothermia: Adult patients who are Therapeutic hypothermia: Adult patients who are comatose (not responding in a meaningful way comatose (not responding in a meaningful way to verbal commands) with spontaneous to verbal commands) with spontaneous circulation after out-of-hospital VF cardiac arrest circulation after out-of-hospital VF cardiac arrest should be cooled to 32–34°C for 12–24 h. should be cooled to 32–34°C for 12–24 h.

Induced hypothermia might also benefit comatose Induced hypothermia might also benefit comatose adult patients with spontaneous circulation after adult patients with spontaneous circulation after OHCA from a non-shockable rhythm or in-OHCA from a non-shockable rhythm or in-hospital cardiac arrest.hospital cardiac arrest.

Brain ischemia during cardiac arrest

(Global vs Focal)

Inflammation and injury

Increased ICP

Poor neurological outcome

Pathophysiology of Pathophysiology of Post-Cardiac ArrestPost-Cardiac Arrest

Physiologic Effects of Physiologic Effects of HypothermiaHypothermia

Desired effects:Desired effects: Decreases the cerebral Decreases the cerebral

metabolic rate (1°C = 5-7%)metabolic rate (1°C = 5-7%) Inhibits influx of Ca & Inhibits influx of Ca &

glutamate accumulationglutamate accumulation Suppresses ischemia-induced Suppresses ischemia-induced

inflammatory cytokinesinflammatory cytokines Reduces disruptions in BBB & Reduces disruptions in BBB &

vascular permeabilityvascular permeability

Physiologic Effects of Physiologic Effects of Hypothermia Hypothermia (cont.)(cont.)

Potential adverse effects:Potential adverse effects: Decreases heart rateDecreases heart rate Decreases phosphate and Decreases phosphate and

potassium concentrationspotassium concentrations Decreases gut motilityDecreases gut motility Increases blood glucose concentrationsIncreases blood glucose concentrations Increases systemic vascular resistanceIncreases systemic vascular resistance Prolongs clotting timesProlongs clotting times May cause diuresisMay cause diuresis May decrease the number and function of May decrease the number and function of

WBCs and plateletsWBCs and platelets

Hypothermia ProtocolHypothermia Protocol

IS THE PATIENT A CANDIDATE IS THE PATIENT A CANDIDATE FOR THERAPEUTIC FOR THERAPEUTIC

HYPOTHERMIA?HYPOTHERMIA?

Inclusion Criteria for Therapeutic Inclusion Criteria for Therapeutic HypothermiaHypothermia

Patient must meet Patient must meet BOTHBOTH criteria: criteria:

Cardiac arrest patient, post resuscitation with Cardiac arrest patient, post resuscitation with return of spontaneous circulation and return of spontaneous circulation and persistent coma (GCS < 6)*persistent coma (GCS < 6)*

Resuscitation time (time of collapse to return of Resuscitation time (time of collapse to return of spontaneous circulation) should be < 1 hourspontaneous circulation) should be < 1 hour

Time from resuscitation to initiation of hypothermia < 6 Time from resuscitation to initiation of hypothermia < 6 hours (Optimally, but up to 12 can be considered)hours (Optimally, but up to 12 can be considered)

Patient is intubatedPatient is intubated

**no level of coma short of brain death precludes cooling.no level of coma short of brain death precludes cooling.

Exclusion Criteria for Therapeutic Exclusion Criteria for Therapeutic HypothermiaHypothermia

AbsoluteAbsolute: (If the patient meets any of the below, : (If the patient meets any of the below, he/she is he/she is NOTNOT a candidate) a candidate) DNR code statusDNR code status Metastatic cancer or other terminal illnessMetastatic cancer or other terminal illness Responds to verbal commandsResponds to verbal commands PregnancyPregnancy Comatose baseline due to CNS depressing Comatose baseline due to CNS depressing

drugs or other possible causedrugs or other possible cause Temperature < 30ºC (86ºF)Temperature < 30ºC (86ºF) Glascow Coma Scale (GCS) GREATER than 6Glascow Coma Scale (GCS) GREATER than 6

RelativeRelative Exclusion Criteria Exclusion Criteria

Hemodynamic instability (MAP < 60mmHg) for more than 30 Hemodynamic instability (MAP < 60mmHg) for more than 30 minutes post resuscitationminutes post resuscitation

Uncontrolled cardiac arrhythmias, multiple arrests/ pulseless periodsUncontrolled cardiac arrhythmias, multiple arrests/ pulseless periods Significant pre-existing neurological ImpairmentSignificant pre-existing neurological Impairment Extremes of ageExtremes of age Prolonged QT interval (> 0.45)Prolonged QT interval (> 0.45) Prolonged hypoxemia (SaO2 < 85%) for greater than 15 minutes Prolonged hypoxemia (SaO2 < 85%) for greater than 15 minutes

after return of spontaneous circulationafter return of spontaneous circulation Delay of greater than 15 minutes to initiation of BLSDelay of greater than 15 minutes to initiation of BLS Patients with known bleeding diathesis or with active ongoing Patients with known bleeding diathesis or with active ongoing

bleedingbleeding Platelet count < 50,000/mLPlatelet count < 50,000/mL Recent surgery (within 14 days)Recent surgery (within 14 days) Active sepsisActive sepsis Etiology of cardiac arrest thought to be caused by trauma or severe Etiology of cardiac arrest thought to be caused by trauma or severe

bleedingbleeding Initial rhythm = asystoleInitial rhythm = asystole

The patient must be managed in three The patient must be managed in three phases:phases:

CoolingCooling MaintenanceMaintenance RewarmingRewarming

Process of Therapeutic Process of Therapeutic HypothermiaHypothermia

Hypothermia DefinedHypothermia Defined

Mild hypothermia = 32-35Mild hypothermia = 32-35◦◦CC Moderate = 28- 32Moderate = 28- 32◦◦CC Severe = 20-28Severe = 20-28◦◦CC

LET’S GET STARTED!LET’S GET STARTED!

Consider inclusion & exclusion criteria Consider inclusion & exclusion criteria

As soon as decision is made to start hypothermia, begin As soon as decision is made to start hypothermia, begin sedation. NO SEDATION VACATION DURING COOLING sedation. NO SEDATION VACATION DURING COOLING PHASE.PHASE.

Induction of hypothermia should begin as soon as possible after Induction of hypothermia should begin as soon as possible after ROSCROSC

Rapid infusion of cold (48°C) IV fluid – 30mL/kg or up to 2 LRapid infusion of cold (48°C) IV fluid – 30mL/kg or up to 2 L

LIFEFLIGHT OF MAINELIFEFLIGHT OF MAINEINDUCED HYPOTHERMIA AFTER INDUCED HYPOTHERMIA AFTER

CARDIAC ARRESTCARDIAC ARREST

Institute cooling as early as possible. Temp goal is 33°C.Institute cooling as early as possible. Temp goal is 33°C. Sedate and paralyze the patient as per Protocol 2.3.; Veccuronium Sedate and paralyze the patient as per Protocol 2.3.; Veccuronium

is preferred. Suppress shivering with neuromuscular blockade.is preferred. Suppress shivering with neuromuscular blockade. Rapid IV infusion of ice cold (4°C). LR. Administer 30 ml/kg IVx1 Rapid IV infusion of ice cold (4°C). LR. Administer 30 ml/kg IVx1

dose over a period of 30 minutes immediately after neuromuscular dose over a period of 30 minutes immediately after neuromuscular blocking agent administered. Maximum of 2 liters LR during blocking agent administered. Maximum of 2 liters LR during transport.transport.

Apply ice packs to patient’s neck, axilla, and inguinal area after Apply ice packs to patient’s neck, axilla, and inguinal area after patient is sedated and paralyzed and iced LR is administered IV.patient is sedated and paralyzed and iced LR is administered IV.

If patient shivering increase sedative and/or analgesia dose prior to If patient shivering increase sedative and/or analgesia dose prior to increasing paralyticincreasing paralytic

Monitor temperature via esophageal temperature probe –as time Monitor temperature via esophageal temperature probe –as time and mission allow.and mission allow.

Consider turning on aircraft AC to assist with cooling enroute.Consider turning on aircraft AC to assist with cooling enroute. Report to receiving tertiary care center.Report to receiving tertiary care center.

In the ICUIn the ICU Draw initial labs Draw initial labs

Correct potassium (goal of 3.5) PRIOR to onset of cooling therapyCorrect potassium (goal of 3.5) PRIOR to onset of cooling therapy

Patients will be on the following protocols:Patients will be on the following protocols: Electrolyte replacementsElectrolyte replacements Glycemic Control/Intensive insulinGlycemic Control/Intensive insulin Neuromuscular blockadeNeuromuscular blockade

Obtain Obtain one setone set of blood cultures of blood cultures 12 hours12 hours after onset of cooling (Hypothermia may mask after onset of cooling (Hypothermia may mask infection)infection)

During warming – BMP q 4 hrsDuring warming – BMP q 4 hrs Perform a thorough skin assessmentPerform a thorough skin assessment

Place temperature probe: PA, Foley or esophageal & rectalPlace temperature probe: PA, Foley or esophageal & rectal

Turn room thermostat to lowest setting during cooling and maintenance phaseTurn room thermostat to lowest setting during cooling and maintenance phase

Prepare for A-line and CVP line insertion.Prepare for A-line and CVP line insertion.

Ventilator circuit – no heatingVentilator circuit – no heating

COOLING PHASECOOLING PHASE

Cool patient to a target temperature of 32º - 34º C (89.6º Cool patient to a target temperature of 32º - 34º C (89.6º - 93.2º F) within 6-12 hours of onset of arrest. Maintain - 93.2º F) within 6-12 hours of onset of arrest. Maintain at target temperature for 24 hours.at target temperature for 24 hours.

Monitor and record VS, CVP, cardiac rhythm and Monitor and record VS, CVP, cardiac rhythm and primary temperature q 30 min. until goal temp is primary temperature q 30 min. until goal temp is achieved.achieved.

Correlate and record secondary temperature source q Correlate and record secondary temperature source q 2hours.2hours.

If unable to achieve target core temperature, consult MDIf unable to achieve target core temperature, consult MD

COOLING PHASECOOLING PHASEShiveringShivering

Thermoregulatory reflex to hypothalmic set pointThermoregulatory reflex to hypothalmic set point

Perform shivering assessment Perform shivering assessment hourlyhourly throughout throughout cooling phase (Palpate mandible to assess for shivering)cooling phase (Palpate mandible to assess for shivering)

If shivering occurs during cooling phase, implement If shivering occurs during cooling phase, implement Critical Care Neuromuscular Blocker orders. Critical Care Neuromuscular Blocker orders. (NO (NO neuromuscular drug holiday during the cooling neuromuscular drug holiday during the cooling phase!)phase!)

Cutaneous warming can be used (anterior surface)Cutaneous warming can be used (anterior surface)

Administration of MagnesiumAdministration of Magnesium

PATIENT SHOULD REMAIN AT PATIENT SHOULD REMAIN AT TARGET TEMPERATURE FOR 24 TARGET TEMPERATURE FOR 24 HOURS.HOURS.

MAINTENANCE PHASEMAINTENANCE PHASE

Once target temp is achieved, monitor and record VS, Once target temp is achieved, monitor and record VS, CVP, cardiac rhythm and primary temperature hourly CVP, cardiac rhythm and primary temperature hourly and PRN during maintenance.and PRN during maintenance.

Assess skin under pads & record every 2 hoursAssess skin under pads & record every 2 hours Correlate and record secondary temperature every 2 Correlate and record secondary temperature every 2

hourshours Monitor and record water temperature in cooling deviceMonitor and record water temperature in cooling device Assess skin every 2 hours for any signs of breakdownAssess skin every 2 hours for any signs of breakdown If patient has recurring malignant dysrhythmias If patient has recurring malignant dysrhythmias

discontinue cooling, begin rewarming and notify MD.discontinue cooling, begin rewarming and notify MD.

REWARMING PHASEREWARMING PHASEActive vs PassiveActive vs Passive

Should begin 24 hours after target temperature achievedShould begin 24 hours after target temperature achieved Proceed with rewarming slowly (0.5° - 1° C per hour) over 6-Proceed with rewarming slowly (0.5° - 1° C per hour) over 6-

8 hours to prevent vasodilation, hypotension and rapid fluid 8 hours to prevent vasodilation, hypotension and rapid fluid & electrolyte shifts.& electrolyte shifts.

Draw BMP q 4 hrs, but DO NOT replace potassium during Draw BMP q 4 hrs, but DO NOT replace potassium during rewarming phase (shifts back into serum from cells)rewarming phase (shifts back into serum from cells)

Discontinue neuromuscular blockers once patient’s Discontinue neuromuscular blockers once patient’s temperature >36ºC, but continue sedation until TOF = 4.temperature >36ºC, but continue sedation until TOF = 4.

If shivering occurs, apply warm blankets or use DemerolIf shivering occurs, apply warm blankets or use Demerol Do not permit hyperthermia in the first 24 hours after Do not permit hyperthermia in the first 24 hours after

cooling.cooling. Administer acetominophen for temp >37ºC (98.6ºF)Administer acetominophen for temp >37ºC (98.6ºF)

SNGH’s ExperienceSNGH’s Experience

Sentara Norfolk General Hospital

Level I Trauma Center

Sentara’s Background Sentara’s Background InformationInformation

VBEMS

SNGH TH PatientsSNGH TH Patients

Sentara Hospitals Combined Sentara Hospitals Combined ExperienceExperience

SHH Combined Experience: SHH Combined Experience: Patients TreatedPatients Treated

SHH Combined Experience:SHH Combined Experience:SurvivorsSurvivors

CONCLUSIONCONCLUSION

Cardiac arrest with widespread Cardiac arrest with widespread cerebral ischemia frequently leads to cerebral ischemia frequently leads to severe neurologic impairment. Induced severe neurologic impairment. Induced hypothermia is a promising method that hypothermia is a promising method that increases the rate of favorable neurologic increases the rate of favorable neurologic outcome and reduces mortality. outcome and reduces mortality.

http://www2.providence.org/phs/news/Pages/Coldtherapy.aspx