1. Management of Fever
There are basically two methods for treating patients with fever
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Administration of an antipyretic drug. |
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Physical cooling. |
2. Targeted temperature management
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Targeted temperature management (TTM) refers to strict temperature control following Cardiac Arrest (CA). |
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Continue therapeutic hypothermia of between 33-36oC for 24 hours, and normothermia for at least 72 hours after return to spontaneous circulation (ROSC). |
2.1. Inclusion criteria for targeted temperature management includes the following
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Post cardiac arrest in or out of hospital where there has been a return to spontaneous circulation (ROSC) and the patient is unresponsive. |
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Comatose adult patients (i.e., Lack of meaningful response to verbal commands) with ROSC after cardiac arrest. |
2.2. Exclusion criteria for targeted temperature management includes the following
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Absolute contraindication: Advanced directive that proscribes aggressive care or a medical scenario in which such care is not appropriate. |
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Relative contraindications ● Active bleeding or blood dyscrasia. ● Hemodynamic instability despite vasoactive medication. ● Arrhythmic storms, in relation to extreme bradycardia. ● Severe prior neurological disease. ● Life expectancy < 6months in relation to co morbidities. ● Pulseless for >60 minutes. ● >12 hours since Return of Spontaneous Circulation. ● Coma due to cause other than cardiac arrest i.e., drug overdose, stroke, pre-existing coma, status epilepticus. |
2.3. Steps of Targeted temperature management
● Initiation
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Cooling should begin as soon as possible after ROSC preferably within 4 hours. |
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Do not delay cooling for routine diagnostics, or to monitor for neurological improvement. Exceptions to early initiation of cooling include the following: ● Patients with resuscitated cardiac arrest who have evidence of ST segment elevation myocardial infarction (STEMI) on electrocardiogram (ECG). In such patients, urgent revascularization takes priority. ● In patients who have documented intracranial hemorrhage, neurology and neurosurgery evaluation takes priority. |
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To initiate cooling, confirm that the patients have been sedated. |
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Neuromuscular blockade may be used to prevent shivering during induction of hypothermia. |
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Aim for a temperature drop of 1° C or more per hour. |
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Hold cooling if temperature is less than 33°C. |
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Wrap hands and feet with dry towels to prevent frostbite and to decrease shivering during period of therapeutic hypothermia. |
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Do not turn off sedation or paralytic agents. |
● Cooling Technique
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Infuse 30 ml/kg bolus of ICE-COLD 0.9% Normal Saline over 30-60 minutes through a peripheral or femoral venous line. |
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Apply ice packs to sides of Neck, bilateral axilla and groin as needed. |
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Flush NG/OG tube with 500 ml ice-cold water; keep it over 15-30 minutes and aspirate it out. |
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Flush Foleys Catheter with 500 ml of ice-cold water, keep it over 15-30 mins and drain it out. |
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Repeat these steps again every 30 mins till the target temperature is met or repeat again during maintenance. |
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Patients with a history of heart failure or severely compromised kidney function, or signs of acute pulmonary edema, should not receive rapid infusions of fluid to induce hypothermia. Surface cooling measures or an IV cooling device should be used instead. |
● Assessment / Monitoring/ sedation during Targeted temperature management
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Continuous temperature monitoring (esophageal, bladder, and rectal temperature) should be done and documented every hour. |
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Core temperatures are more accurate than the peripheral temperature. |
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Invasive blood pressure monitoring with an arterial catheter and the maintenance of mean arterial pressure (MAP) of 80-100 mmHg ensuring a cerebral perfusion pressure of at least 60 mmHg. |
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Pulse oximetry: A value of 94-98% should be maintained. |
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Continuous ECG monitoring to ensure early detection of any alteration. |
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Continuous EEG monitoring, recommended especially inpatients subjected to neuromuscular block, in order to detect possible myoclonus. |
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Assess skin for signs of frostbite q 2 hours. |
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Obtain baseline CBC, electrolytes, Troponin, CPK, CPK-MB, Lactate, Glucose, Magnesium, ionized Calcium, ABG and PT/PTT. |
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Monitor Electrolytes every 6 hours; monitor ABG, PT/PTT, Mg2+, and ionized Ca 2+ at least every 12 hours. |
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Monitor blood glucose every hour. |
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Continue standard supportive care for mechanically ventilated, paralyzed patients, including DVT prophylaxis, head of bed elevated >30 Degree and attentive skin care. |
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Monitor for potential complications which includes coagulopathy, sepsis, bradyarrhythmia, hyperglycemia, hypokalemia etc. |
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Administer sedation during TTM to suppress shivering and common approaches to sedation in post-cardiac arrest patients include the following ● Continuous infusions of propofol (25 mcg/kg/minute to a maximum dose of 50 mcg/kg/minute) and fentanyl (25 mcg/hour to 100 mcg/hour). ● Propofol infusion with intermittent fentanyl boluses. ● Continuous infusion of midazolam (2 to 10 mg/hour) in hypotensive patients. ● In patients who are refractory to escalated sedation, dexmedetomidine, neuromuscular blocking agents (NMBAs), and meperidine are options but have their own limitations. |
● Process of Rewarming after Targeted temperature management
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Discontinue all sedative and analgesic infusions and NMBAs simultaneously at the end of the 24-hour cooling period. |
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Slow rewarming targeting a rise in temperature at a rate of 0.25 to 0.5°C per hour until normothermic. |
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Watch for shivering, electrolytes, vitals and features of cerebral edema during the process of rewarming. |
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Avoid fever during the rewarming phase and for 72 hours. |
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If desired temperature is not achieved, rate of rewarming can be increased by raising the room temperature, applying a convective heating device, using heating lamps, or warming the inspired air via the ventilator heating circuit on the humidifier. |
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Once target temperature is achieved continuously monitor temperature over next 72 hours and maintain the target temperature of 36-37°C. |
Further Readings:
1. Bernard, S. A., Gray, T. W., Buist, M. D., Jones, B. M., Silvester, W., Gutteridge, G., & Smith, K. (2002). Treatment of comatose survivors of out-of-hospital cardiac arrest with induced hypothermia. New England journal of medicine, 346(8), 557-563.
2. Dankiewicz, J., Cronberg, T., Lilja, G., Jakobsen, J. C., Levin, H., Ullén, S., ... & Nielsen, N. (2021). Hypothermia versus normothermia after out-of-hospital cardiac arrest. New England Journal of Medicine, 384(24), 2283-2294.
3. Hypothermia after Cardiac Arrest Study Group. (2002). Mild therapeutic hypothermia to improve the neurologic outcome after cardiac arrest. New England Journal of Medicine, 346(8), 549-556.
4. Nielsen, N., Friberg, H., Gluud, C., Herlitz, J., & Wetterslev, J. (2011). Hypothermia after cardiac arrest should be further evaluated—a systematic review of randomised trials with meta-analysis and trial sequential analysis. International journal of cardiology, 151(3), 333-341.
5. Nolan, J. P., Sandroni, C., Böttiger, B. W., Cariou, A., Cronberg, T., Friberg, H., ... & Soar, J. (2021). European resuscitation council and European society of intensive care medicine guidelines 2021: post-resuscitation care. Resuscitation, 161, 220-269.
