Background: Post-cardiac arrest patients are among the sickest groups of patients seen in the Emergency Department. They are difficult to study, which leads to endless questions about how to best care for them. Below we address the available evidence on four of these controversies: oxygen therapy, hemodynamic management, cardiac catheterization and head CT. We recognize the limitations to the available data and attempt to offer the best recommendations we can.
- Avoiding both hypoxia and hyperoxia is important. Hyperoxia may lead to cerebral vascoconstriction and production of free radicals.
- Hyperoxia (PaO2 >300) on first ICU blood gas was associated with increased mortality compared to normoxia and hypoxia (OR 1.8 95%CI 1.5-2.2.) (Kilgannon 2010)
- Titration of oxygen in the pre-hospital period following OHCA was found to not be feasible due to concern for hypoxia, however it is feasible to titrate oxygen safely after arrival in hospital. (Young 2014)
- A Systematic Review and Meta-analysis by Wang et. al. found that post-ROSC hyperoxia was significantly associated with in-hosiptal mortality (OR 1.4) but was not significantly associated with poor neurologic status at hospital discharge. (Wang 2014)
- Bottom line: Target a SpO2 of 92-95%. Titrate down fiO2 to the minimum amount required to achieve this goal as hyperoxia has been associated with worse outcomes
- Post-ROSC patients are often hypotensive due to the underlying etiology of cardiac arrest or secondary to ischemia-reperfusion injury
- Blood pressures are likely to drop as the effect of vasoactive substances (most commonly epinephrine) given during cardiac arrest wears off.
- The American Heart Association (AHA) recommends avoiding and immediately correcting hypotension (systolic blood pressure <90 mmHg, MAP <65 mmHg) during postresuscitation care (Class IIb) (Callaway 2015)
- A retrospective study showed that survivors of cardiac arrest had higher MAPs at all time points compared to non-survivors (this is also the case among patients requiring vasoactive agents), suggesting that patients may benefit from a higher goal MAP (>80 mm Hg.) (Beylin 2013)
- There is an ongoing RCT in Belgium (Ameloot 2017) to determine if a target MAP of 85-100 mm Hg in comatose survivors of cardiac arrest has improved outcomes compared to those with a target MAP > 65 mm Hg.
- Bottom line: Avoiding hypotension is important in post-cardiac arrest patients. Although limited, available evidence suggests that a higher goal MAP may improve survival.
- Coronary artery disease is the most common cause of cardiac arrest. However, it remains difficult to predict which patients will benefit from cardiac catheterization after ROSC.
- The AHA recommends emergent coronary angiogram of out of hospital cardiac arrest (OHCA) patients with suspected cardiac etiology of arrest and ST elevation on ECG (Class I). Emergency coronary angiography is reasonable for select (eg, electrically or hemodynamically unstable) adult patients who are comatose after OHCA of suspected cardiac origin but without ST elevation on ECG (Class IIa.) (Callaway 2015)
- >25% of patients without STEMI on their ECG have a coronary occlusion requiring PCI (Hollenbeck 2014)
- Patients who underwent PCI after VF arrest have decreased mortality (OR 0.30.). However more of a benefit was seen in younger patients (Cronier 2011)
- A combination of ECG criteria (ST-elevation and/or depression and/or LBBB and/or non-specific QRS) in post-cardiac arrest patients was 100% sensitive and 45% specific for an ultimate diagnosis of MI (Sideris 2011)
- A Systematic Review and Meta-analysis of non-randomized controlled studies found that cardiac catheterization was associated with increased survival (OR 2.77) and increase survival with good neurologic outcome (OR 2.20) (Camuglia 2014)
- This review did not control for ECG pattern
- A potential confounder is that patients who had coronary angiogram may have received more attentive care
- Post-VF arrest patients with non-ST elevation in ECG have been found to have better outcomes if coronary angiogram was performed (survival 65.6% vs 28.6% also with better neurologic outcomes among survivors in cath group) (Hollenbeck 2014)
- A recent algorithm advocates for taking into account “Unfavorable Factors” that indicate patient is less likely to benefit from cath when deciding whether to obtain coronary angiogram (Rab 2015)
- Bottom Line: Almost all STEMIs should go to the cath lab immediately. Strongly consider cath in non-STEMI post-ROSC patients if patients had an initial shockable rhythm, there is a high suspicion of coronary etiology or no other etiology of arrest is found. Patients who undergo coronary angiogram seem to do better than those who do not but this may be a result of more attentive/aggressive care.
Non-Contrast Head CT (NCHCT)
- Neurologic emergencies are a common cause of OHCA (2.3-16%) (Reynolds 2017)
- Up to 79% of head CTs done in post-ROSC patient had abnormalities (Naples 2009)
- CT scans prompted diagnostic and therapeutic changes in 39% of patients in whom it was performed
- Percentages are likely biased as it is unclear what prompted clinicians to perform a NCHCT or to not perform one
- NCHCT led to changes in management in up to 34% of patients in whom it was performed (Reynolds 2017)
- Changes in management: Triaged to NICU, neurosurgery consult, hyperosmolar therapy, reversal of coagulopathy, prophylactic anti-epileptic therapy, stopping targeted temperature management, placing DNR orders
- However, only 1 out of 20 patients in whom CT changed management survived to discharge (non-neurologically intact patient)
- Bottom Line: NCHCT may change management in post-cardiac arrest patients but it is unclear which patients should have a NCHCT performed.
Take Home Points
- Hyperoxia is associated with worse outcomes, aim for SpO2 92-95% and titrate down fiO2 as soon as possible
- Avoid and correct hypotension. Consider a higher goal MAP such as 80 mm Hg
- Activate the cath lab for STEMIs, patients with an initial shockable rhythm or if you suspect a cardiac etiology of arrest.
- NCHCT may change management in post-cardiac arrest patients but it is unclear which patients should get a NCHCT
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