Outline the important management principles in treating a patient who has been admitted to your ICU intubated and ventilated immediately following successful resuscitation from an out of hospital cardiac arrest.
Post-resuscitation care has an impact on overall outcome and consists of ongoing resuscitation and organ support, neuroprotection, treatment of the cause of the cardiac arrest and management of underlying co-morbidities.
- Check adequacy of airway, ETT position, ventilation and circulatory status
- Appropriate monitoring and intravenous access
- Control CO2
- Avoid hypoxia and hyperoxia
- Stabilise circulation with fluid therapy and vasoactive drugs
- Consider early echo
- Diagnosis / treatment of acute coronary syndrome with angiography/PTCA or thrombolysis
- Evaluation for pacemaker or ICD if primary dysrhythmia
- Mechanical support - use of IABP for cardiogenic shock in acute MI has recently been questioned.
- Some centres may consider use of ECMO
- Therapeutic hypothermia at 32-34oC for 12-24 hr appears to be neuroprotective with improved neurological outcome although the optimal method and timing of cooling is still to be determined.
- Treatment of seizures
- Diagnosis and management of precipitating event
Let us deconstruct this answer. This question interrogates the candidate's ability to approach a post-arrest patient in a systematic manner. Of course, the natural tendency of any ICU trainee would be to immediately start ranting about therapeutic hypothermia (hard to blame them, of course - it is indeed an exciting topic). And then to strat ranting about family discussions. The savvy candidate will note that there is no mention of family discussions in the model answer.
The answer is organised in a familiar A-B-C-D of resuscitation. I have both a brief summary of post-resuscitation care, and a prolonged elaboration of this topic. In brief, a structured answer would resemble the following:
- The comatose patient should be intubated, and the ETT secured.
- Mechanical ventilation (mandatory mode) should be commenced
- No unique recommendation - standard ventilation
- Aim for normoxia and normocapnea.
- Avoid hyperoxia.
- Anticipate aspiration pneumonia, pneumothorax, pulmonary oedema, pulmonary contusions, and ARDS.
- Anticipate distributive shock, potentially with cardiogenic shock
- Vasopressor support, inotropes and fluids as required to maintain a MAP >65
- Urgent coronary angiogram, if there is no obvious non-cardiac cause of arrest.
- Urgent TTE
- Watch for QTc prolongation
Disability (.. or prevention thereof)
- Therapeutic hypothermia to 32-24° if the patient remains comatose;
- Targeted temperature management is a valid alternative, and may be preferred
- Avoid hyperthermia
- Sedation and neuromuscular blockade; avoid benzodiazepines.
- Watch for hypokalemia
- Replace electrolytes to prevent arrhythmias
Fluids and renal function
- Renal function may deteriorate due to hypoxic injury
- Hypothermia may result in hyperviscosity; use crystalloid
- Anticipate a vigorous diuresis with hypothermia
Gastrointestinal and nutritional support
- Normoglycaemia maintained with an insulin-dextrose infusion
- No need to start feeds until after rewarming
- Avoid invasive procedures while hypothermic
- Platelet dysfunction coagulopathy and thrombocytopenia of hypothermia are reversible.
- If the patient has ongoing uncontrolled bleeding, therapeutic hypothermia is contraindicated.
- Most common complication is pneumonia (staphylococcal)
- Most common bacteraemia is gram negative (bacterial translocation from the gut)
- In hypothermia, leucocyte migration and phagocytosis are impaired, predisposing to infection.
First, the college wants you to acknowledge that the patient is intubated, and that you are concerned about their ETT position. This, as a matter of general principle, is never wrong.
Secondly, the college wants you to acknowledge that you would pursue normoxia and normocapnea.
TTE, angiography, fluids and vasopressors are mentioned - again, this is consistent with the AHA guidelines.
Therapeutic hypothermia is mentioned, and it would be amiss to write an answer to this question without discussing this.
Overall, the model answer expects nothing suprising or inventive from the candidate. The only unusual feature is the mention of ECMO, which (unlike the rest of the answer) does not have strong evidence behind it in post-resuscitation care.
Kilgannon, J. Hope, et al. "Association between arterial hyperoxia following resuscitation from cardiac arrest and in-hospital mortality." JAMA: The Journal of the American Medical Association 303.21 (2010): 2165-2171.
Peberdy, Mary Ann, et al. "Part 9: Post–Cardiac Arrest Care 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care." Circulation 122.18 suppl 3 (2010): S768-S786.
Stub, Dion, et al. "Post Cardiac Arrest Syndrome A Review of Therapeutic Strategies." Circulation 123.13 (2011): 1428-1435.