Post-Cardiac Arrest: How to Develop and Implement a Standard Therapeutic Hypothermia Protocol?

Abstract

Therapeutic Hypothermia (TH) for post cardiac arrest is becoming standard therapy since it has been shown to improve neurologic and survival outcomes in cardiac arrest survivors. Two ground-breaking prospective trials in 2002 showed that inducing hypothermia in patients who were successfully resuscitated from cardiac arrest due to ventricular fibrillation (VF) resulted in better neurologic recovery and survival of these patients [1, 2]. Following these and subsequent studies which showed promising results with TH in cardiac arrest survivors, the International Liaison Committee on Resuscitation (ILCOR) and the American Heart Association (AHA) issued guidelines that recommend the use of mild therapeutic hypothermia ( 32–34°C) for 12–24 h in all cardiac arrest survivors [3, 4].

Appendix

Hartford Hospital Therapeutic Hypothermia Protocol/Order Set

Inclusion/Exclusion criteria must be completed prior to initiating therapy

• Inclusion criteria:

  • Survivors of cardiac arrest (inpatient or outpatient)

  • Unresponsive (defined as total Glasgow coma scale (GCS) <8 or motor score <4 if intubated)

  • Blood pressure >90 mm of Hg systolic (with our without vasopressors)

  • Intubated

• Exclusion criteria:

  • Patients who are do-not-resuscitate (DNR) status

  • Significant immunologic compromise (e.g. AIDS, Leukemia)

  • Active sepsis

  • Hemodynamic instability

  • Down time >30 min to first responder (a relative contraindication)

  • Active bleeding (a relative contrain­dication)

  • Causes of coma other than cardiac arrest/hypoxic encephalopathy

• 1. Initiate Patient Comfort/Sedation Guidelines. Titrate to maintain RASS −3 to −5

  • (a) Fentanyl (Sublimaze) IV Bolus 1–2mcg/kg/h (Dilute with 5 ml D5W or NS); IV continuous infusion 1mcg/kg/h (10mcg/ml NS)

  • (b) Propofol (Diprivan) IV 10 mg/ml 100 ml; start at 5mcg/kg/min then titrate to SAS 2–3. Use per propofol protocol (not to be used as the sole sedation agent when using a neuromuscular blocker)

  • (c) Midazolam (Versed) IV Bolus 2–4 mg IVPush IV Continuous Infusion (2–4 mg/h)

• 2. Neuro-Muscular blockade (Patient must be ventilated, monitor patient using TOF Micro Stim Device)

  • (a) Cisatracurium (Nimbex) IV Bolus 0.1–0.2 mg/kg (1–5 mg/ml D5W or NS) IV Infusion 0.5–10mcg/kg/min (200 mg/200 ml D5W or NS)

  Remember that patient must have Benzo­diazepine for amnesia and opiate for neuromuscular pain with a paralytic per hospital policy

• 3. Shivering

  • (a) Buspirone (Buspar) 15 mg PO  ×  1 ASAP

  • (b) Meperidine(Demerol) 25–50 mg IV Q4 h PRN shivering (Limit/avoid use in patients with renal impairment)

  Limit/avoid Demerol use in patients with renal impairment. Demerol (Meperidine) may induce seizure activity in some patients

• 4. Electrolyte Replacement

  • (a) K⁺, iCa⁺⁺, Mg⁺⁺, Phos⁻⁻ per protocol

• 5. Hypotension with Normal Ejection Fraction (EF)

  • (a) Norepinephrine(Levophed) 8 mg/500NS titrate to MAP >70 mmHg

  • (b) NaCl 0.9% titrate to maintain MAP >70 mmHg

• 6. Hypotension with EF <30 consider: (consult cardiology for use of these meds)

  • (a) Dobutamine infusion at 2.5 mcg/kg/min titrate to maintain cardiac index >2.0

  • (b) Dopamine at 2.5 mcg/kg/min to maintain MAP >70 mmHG

  Make recommendation for Cardiac output, and SV02 monitoring with therapy

• 7. Nursing (1:1 ratio for 24 h)

  • Initiate Cooling ASAP (Cool/Warm to 32–34°C) and maintain for 24 h

  • Set device to Max Mode Cooling

  • Inform Respiratory Therapist of Therapy

  • Bed Rest with HOB elevated 30°

  • Vitals: Q15 min during initiation of cooling until therapeutic hypothermia achieved

  • Q 1 h during maintenance phase including shivering assessment

  • Q 15 min for 1 h during initiation of re-warming then Q1 h

  • Neuro checks Q2 h

  • Use Bispectral Index (BIS) monitor to titrate sedation if available (BIS reading between 40 and 60)

  • EKG on admission then Q8 h for 24 h

  • Goal temperature 32–34°C. Call MD if temperature <32°C or if 34°C not achieved within 4 h

  • Consider 500 cc boluses of 4°C IVF if target temperature not achieved in 4 h

  • Ice packs to groin and axilla to achieve target temperature in 4 h; also consider paralytic therapy

  • Electrolyte Replacement Protocol

  • Skin integrity checks per Protocol

  • Oral Care Protocol

  • Insert Salem Sump nasogastric tube, attach to low intermittent suction

  • Insert Foley catheter with temperature probe and attach to cooling device if not available

  • Insert Rectal Temperature probe and attach to cooling device

  • Pressure Ulcer prevention protocol

  • Room temperature should be turned OFF during induction phase

  • Room temperature should be turned back on during re-warming phase (if not already on)

  • Intake and Output hourly

  • Assess for Shivering

  • Daily weights

  • Maintain Arterial Line

  • Maintain Central Venous Lines (Zoll Icy® Cath/Quattro®, 72 h)

  • Maintain target temperature (32–34°C) for 24 h then initiate re-warming

  • Set internal cooling device target temp 37°C set rate to 0.35–0.5°C/h

  • Do not exceed 0.5–1°C/h during re-warming phase

• 8. Diet/ Nutrition

  • (a) NPO  ×  48h

  • (b) Level 1 Nutrition Consult

• 9. Laboratory

  • (a) Post arrest

    • i. CBC, Chem 10, Base line nutrition lab panel, PT/PTT/INR, DIC panel, Cardiac enzymes, Troponin, ABG, LFT’s, Lactate, Ammonia, BNP, Type and Screen, Amylase, Lipase, S-P100 and Pan Culture

  Q4 – 6 h (Refer to guidelines for frequency of labs)

• 10. Radiology

  • (a) Chest X-ray post arrest and QD

• 11. Cardiology consult

  • (a) Consult cardiology in all cases. If cardiac catheterization is indicated, hypothermia should not be delayed.

• 12. EKG on admission, then Q8 h for 24 h, then QD

• 13. Echocardiogram

• 14. Neurology consult

• 15. Continuous EEG monitoring preferred

• 16. Respiratory Care

  • (a) Ventilator Pressure Control

  • (b) Triage Respiratory

  • (c) Ventilator Humidifier should be turned OFF and HME should be used during cooling phase

  • (d) Ventilator Humidifier should be turned ON and HME removed during re-warming phase

• 17. Skin

• 18. Please refrain from bathing patients as it may exacerbate shivering. Spot cleaning should be the preferred intervention. Remember shivering causes increased O₂ consumption.

What Data Do I Need?

• 1. Review patient eligibility, any contraindications, advanced directives and overall prognosis

• 2. Discuss related issues with health care proxy (Family meeting).

• 3. Exclude other causes of coma (mass lesions, metabolic coma, seizures etc.)

• 4. Document baseline neurological evaluation

Equipment List (What Do I Need?)

(All equipment available in CCU in outer closet with key available at the nursing station)

• 1. Zoll Femoral Line Kit (Icy^®/Quattro^® Catheter: 4 days, 96 h)

• 2. Zoll Cool Guard^® Machine/XP Thermogard^® & Start Up Kit with 500 cc 0.9%NaCL

• 3. A-line (SVO2) Kit (FloTrac^® sensor and Vigileo® Monitoring device)

• 4. Two 1 l bags of Iced 0.9% NaCL 4°C stored in pharmacy

• 5. Order Nimbex, Versed, and Fentanyl drips with Iced NaCL

• 6. Foley temp probe (Rectal temperature probe)

• 7. Neuromuscular Blockade equipment (TOF Micro Stim Device)

• 8. Two 18″ gauge peripheral IV sites

• 9. Two pressure bags (for arterial line and rapid Iced Saline infusion)

What to Do

Note: Data gathering, Monitoring, and Inter­ventions are all initiated immediately and carried simultaneously when feasible

• Cooling procedure

  • 1. Initiate Sedation with Propofol prior to inducing hypothermia (Versed can be used as alternate to Propofol). Consider paralytic bolus (Nimbex/Vecuronium) to facilitate cooling process. Use Demerol for shivering along with Propofol.

  • 2. Draw Labs as ordered: Chem10, CBC, PT/PTT/INR, D-Dimer, Fibrinogen, CPK-MB, Troponin, Lactate, Ammonia, Amylase, Lipase, Type and Screen, Pan Cultures, Albumin, Pre Albumin, Transferrin, BNP, ABG, S-P100 and LFT’s

  • 3. Infuse Iced 0.9% NaCl 1–2 l (or 40 ml/kg) over 30 min (peripheral catheter preferred but is not mandatory)

  • 4. Insert Line and connect Zoll machine and set to maintain temp at 32–34°C

  • 5. Turn off heat to room and Ventilator (Recommended)

  • 6. Titrate sedation, and consider using Bair Hugger® and Meperidine (Demerol) for signs of mild to moderate shivering in maintenance phase. (Do not use Bair Hugger® (heat) during Induction)

    • Shivering Scale: Mild Shivering (Facial tremors)

    • Moderate Shivering (Extremity tremors)

    • Severe Shivering (Full body tremors)

  • 7. Start antibiotics, Ampicillin-Sulbactam (Unasyn) 1.5 g IV now and Q6 h  ×  3 days then re-assess.

  • 8. Initiate paralysis with Nimbex only if you are not reaching target temperature within 6 h, or patient experiences moderate to severe shivering on sedation with Meperidine (Demerol), Propofol and Bair Hugger®. Paralysis guided by pupil exam, TOF Micro Stim Device monitor

  • 9. Also consult Palliative care, Social Services and Life Choice (for Organ Donation) when time permits.

• When therapeutic hypothermia is reached (32–34°C):

  • 1. Reschedule Unasyn 1.5 g IV Q6 h 72 h from time of first dose (then reassess by chest X-ray for signs of aspiration pneumonia after 72 h)

  • 2. Chem10, ABG

  • 3. Maintain sedation, consider Meperidine­(Demerol) and Bair Hugger^® to control shivering

  • 4. If unable to control shivering consider Nimbex gtt with TOF Micro Stim Device monitor (remember an amnesic and analgesic must be used with a paralytic per hospital policy).

• At 4th hour

  • 1. Chem 10, repeat ABG if needed (treat electrolyte imbalances)

  • 2. CPK-MB Troponin (Oral Care Protocol should be started)

  • 3. Unasyn may need to be given (per scheduled dose)

• At 8th hour

  • 1. Chem 10,

  • 2. Possible repeat ABG (consider sodium bicarbonate gtt for acidosis)

• At 12th hour

  • 1. Chem 10, CPK-MB, Troponin

• At 16th hour

  • 1. Chem 7, ABG if needed

• At 24th hour

  • 1. CBC, PT/PTT/INR, Chem 10, ABG

  • 2. Begin re-warming (After 24 h of therapeutic hypothermia 32–34°C)

  • 3. Set cooling device to 0.35°C/h (controlled rate)

  • 4. When re-warming is complete maintain patient in Max Mode for possible rebound hyperthermia (Icy® Cath/Quattro® is good for 4 days 96 h)

  Note machine will automatically switch to Max Mode after re-warming at no more than 0.5–1°C/h

Basic Maneuvers

• Consider holding paralysis if used and begin sedation holidays as per hospital guidelines

• Other considerations:

  • Resume sedation/paralysis if shivering reoccurs

  • Anticipate relative volume depletion-add fluids as indicated

  • Anticipate possible hypotension

  • Anticipate possible rise in serum K⁺

  • Restart HME on ventilator/Turn heat back on in room (if turned off)

  • Anticipate re-cooling if patient seizure activity occurs

• Refer to Seizure guidelines with any seizure activity

• As patient reaches normal (36–37°C) tem­perature

  • Chem 7, ABG

  • Repeat neurological evaluation while weaning sedation as tolerated

  • CXR – Pneumonia/aspiration is common in this population

  (Note: Icy^®/Quattro^® Catheter is good for 3 days/72 h)

• Daily neurological evaluation, assess for infections/bleeding complications

• Don’t forget Life Choice, Palliative care and Social Services consults