Common Issues in Therapeutic Hypothermia
1) Bradycardia: may occur during induced hypothermia (even to as low as 35 bpm) and except in rare cases, is NOT a reason to discontinue hypothermia.
If bradycardia is severe, associated with persistent hypotension, and is not responsive to fluid and vasopressor therapy, a decision in conjunction with medical control to discontinue hypothermia may be made.
2) Dysrhythmias: generally does not occur unless temperatures fall < 30*C and hypothermia related ventricular fibrillation is rare unless temperature is < 28*C.
3) Hypotension: often occurs during induced hypothermia. (Also frequently occurs due to the post-arrest state and not necessarily due to the hypothermia) Except in rare cases, hypothermia should NOT be stopped due to hypotension. Continue to support the MAP with fluid boluses, vasopressors, and inotropes as indicated.
4) Bleeding: antiplatelet and antithrombotic effect of hypothermia is minimal at or around 34*C. In addition, most of the bleeding risk associated with hypothermia involves an impaired ability to generate NEW clots (not necessarily in disruption of clots already formed). Thus for minor bleeding (around IV sites etc) do NOT stop hypothermia. Instead correct acidosis and minimize any further trauma to the patient.
5) Shivering: problematic for the post-cardiac arrest patient, as it increase cerebral oxygen consumption, systemic oxygen consumption, and CO2 production etc. Furthermore, it can severely impede achievement and maintenance of target temperature. It should be monitored for and aggressively treated with appropriate sedation. Paralytics are an option in the transport environment but only after aggressive attempts at adequate sedation are made.
*** More information and training to come in future months as ACMC strives to enhance our ability to initiate and maintain therapeutic hypothermia in the transport environment***