(Click here to return to the Pediatric Surgery @ Brown Home Page)

HYPOTHERMIA

These pages are excerpted from the Trauma Resident Handbook, Rhode Island Hospital Department of Surgery, Division of Trauma - updated 2001. The policies herein are intended to serve as guidelines only. Individual circumstances need to be considered as there may be times when it is appropriate or desirable to deviate from these guidelines. These educational guidelines will be reviewed and updated routinely.

Definitions of Hypothermia

mild	> 32 - 35° C	> 90 - 95° F
moderate	> 28 - 32° C	> 82 - 90 ° F
severe	25-28° C	77-82° F
extreme	< 25° C	< 77° F

INDICATIONS FOR CORE REWARMING (No bypass)

• Moderate hypothermia (> 28 - 32° C) with any perfusing cardiac rhythm
• Severe hypothermia, 25 - 28° C with stable cardiac rhythm¨

INDICATIONS FOR CARDIOPULMONARY BYPASS

• Moderate hypothermia, > 28 - 32° C (> 82 - 90° F) with cardiac arrest (or non-perfusion despite electric cardiac activity)
• evere hypothermia, < 25 - 28° C (77 - 82° F) with cardiac arrest or unstable cardiac rhythm*
• extreme hypothermia < 25° C (77° F) with or without cardiac arrest
• Moderate or severe hypothermia, managed with core rewarming, who develops cardiac arrest
• Moderate hypothermia managed with core rewarming who remains hypothermic and fails to regain stable cardiac rhythm¨ and adequate perfusion after 30 minutes of active rewarming

*Bradycardia alone does not constitute unstable cardiac rhythm in the hypothermic patient.

EXCLUSION FROM CARDIOPULMONARY BYPASS

• Only at the discretion of the ED/Trauma team and Bypass team
• Severe injury not compatible with life
• Immobile frozen body

TYPES OF CARDIOPULMONARY BYPASS

• Femoro-femoral bypass in all patients
• Addition of atrial-aortic bypass (median sternotomy) if:
  • Cardiac arrest
  • Inadequate flow rates/slow rewarming (< 0.5° C/min)
  • Small children (< 20 kg)
  • At the discretion of the cardiopulmonary bypass team

PROTOCOL
1. Determination of hypothermia

• Moderate, severe or extreme hypothermia (= 32° C, or 90° F) rectal, vesical (thermistor bladder catheter), and confirmed esophageally (core temperature); or any hypothermia with cardiac arrest:
  • Notify Trauma Team/Pediatric Surgery Service (Level I Trauma)
  • ED physician notifies O.R. desk to activate bypass protocol: operating room set-up, cardiac anesthesiologist, perfusion team and cardiac/bypass surgeon

2. Initial management

• Patients with temp between 25 and 28° C (77 - 82° F) and stable cardiac rhythm, or between 28 and 32° C (82 - 90° F) and any perfusing cardiac rhythm
  • Ambient temperature at 32° C (90° F)
  • Contact rewarming (Bair Hugger® )
  • Warmed humidified oxygen by mask (40° C) or ET tube (40 - 50° C)
  • Intravenous fluids: 40° C by Level l rewarmer
  • CBC, serum glucose + electrolytes + BUN/Crea + Ammonia, PT/PTT, Fibrinogen, ABG, T&C for 2 U of PRBC
  • Nasogastric tube; lavage with NS at 40° C
  • Bladder catheter; lavage with NS at 40° C
  • Temperature monitoring by esophageal and bladder thermometers
  • If rewarming < 1° C/15 minutes: add (choice and order at discretion of ED/Trauma team)
    • Peritoneal lavage with NS at 40° C
    • (Bilateral) (double) tube thoracostomy and pleural lavage with NS at 40° C
• All patients with temp <32° C (90° F) in cardiopulmonary arrest, 25 - 28° C (77 - 82° F) and unstable cardiac rhythm, or < 25° C (77° F) regardless of cardiac rhythm
  • CPR
  • No attempts at core rewarming in E.D.
  • Full volume resuscitation
  • CBC, serum glucose + electrolytes + BUN/Crea + Ammonia, PT/PTT, Fibrinogen, ABG, T&C for 2 U of PRBC
  • Nasogastric tube, bladder catheter
  • Arterial line
  • Temperature monitoring by esophageal and bladder thermometers
  • Transfer to OR/bypass ASAP

3. Cardiopulmonary bypass

• Performed in the operating room only
• Full cardiopulmonary bypass circuit set-up by the perfusion team
• Full systemic anticoagulation to maintain activated clotting time at 450-480 sec, unless absolute contraindication (severe associated trauma) - at discretion of the bypass team
• Intravenous antibiotics: e.g., Cefazolin
• Patient < 20 kg: consider immediate median sternotomy and central (atrial-aortic) bypass
• Patient > 20 kg: Cannulation of femoral artery and vein - cannulas appropriate for patient size
• Median sternotomy and atrial-aortic bypass if inadequate rewarming or flow, cardiac arrest, or at discretion of bypass team
• Rewarming rate: 0.5-1.0° C/minute

4. Bypass termination

• Consider ultrafiltration or hemodialysis using a hemoconcentrater before decannulation
• Bypass termination when:
  • Core temp > 37° C and spontaneous-stable cardiac rhythm and weanable to mechanical respirator
  • Severe injury incompatible with life (pronounce dead)
  • Failure to wean from bypass (pronounce dead)
• Based on the available literature and our own experience, we do not believe that extracorporeal membrane oxygenation (ECMO) should be utilized to sustain hypothermia victims who, once rewarmed, do not regain sufficient cardiorespiratory function to be weaned from extracorporeal bypass, even after optimal conditions have been met (including the active treatment of acute pulmonary edema). Therefore, these patients will be declared dead.

5. Bypass team

• Perfusionist on call
• Cardiac anesthesiologist
• For pediatric patients: pediatric anesthesiologist
• Surgeon qualified to perform cardiopulmonary bypass
• Cardiac surgeon
• Pediatric surgeon with special privileges in cardiopulmonary bypass
  

Click here to return to Hasbro Children's Hospital Surgery Handbook Home page

.