Resident Journal Review: Post Resuscitation Care

Daniel Boutsikaris, MD; Michael Scott, MD; Samantha Wood, MD; David Wacker, MD; Ali Farzad, MD; Michael Allison, MD

Disclosures

December 15, 2011

In This Article

This edition of Resident Journal Review starts with a brief review of the current guidelines regarding therapeutic strategies and care of the post cardiac arrest patient. From there, the article reviews several recently published studies relating to this topic. The intent of this format is to provide the reader with both the most current guidelines, as outlined by the American Heart Association (AHA), in addition to a literature update since their publication.

Contemporary Reviews in Cardiovascular Medicine. Post Cardiac Arrest Syndrome: A Review of Therapeutic Strategies. Stub D, Bernard S, Duffy S, Kaye D. Circulation. 2011; 123:1428-1435.

Cardiac arrest affects approximately 325,000 people each year in the U.S. Approximately 24% of persons with cardiac arrest will survive to hospital admission, but nationally, only about 8% will survive to discharge. The majority of morbidity and mortality in these patients is the result of cerebral and cardiac injury. Following return of spontaneous circulation (ROSC ), a complex array of pathophysiologic processes occurs. Collectively, this is referred to as the post-cardiac arrest syndrome (PCAS). This syndrome includes four entities: systemic ischemia/reperfusion response, brain injury, myocardial dysfunction and persistence of the precipitating etiologies of arrest.

Regional Systems of Care

Recent studies, both nationally and internationally, have demonstrated improved outcomes at institutions capable of optimizing all facets of care for the post cardiac arrest patient. Of particular importance is a center’s ability to perform invasive cardiac procedures including, but not limited to, percutaneous coronary intervention (PCI). This data suggests that the development of post cardiac arrest centers, in association with regionalization of care, may provide the best opportunity to maximize survival in these patients. Further, having centers that are well versed in the care of these patients is paramount, especially when considering the acuity of illness and the time sensitivity of needs in this population. For the emergency provider working in systems where they are expected to provide first responders with hospital dispositions, this information may soon weigh heavily in their decisions. A decision that becomes even more difficult when patients may need to endure longer transport times to reach such institutions. Fortunately, recent literature has not found an association between longer transport times and adverse events. Although more work still needs to be done in this area before specific recommendations can be made, it is likely that many systems will resemble those already in place for the stroke, STEMI or trauma patients. Additionally, the majority of study in this area has involved patients who achieved ROSC and not those where CPR remained in progress.

Initial Management

The treatment of these patients should be viewed as similar to other groups of critically ill patients and requires a comprehensive, goal directed approach. In the setting of post cardiac arrest care, interventions should focus on oxygenation/ventilation, circulatory support, institution of mild therapeutic hypothermia (TH) and strong consideration for cardiac catheterization. In addition, overall optimization of care in the critically ill, including glucose control, seizure monitoring and electrolyte replacement, are all extremely important. If seizures are noted, they should be aggressively managed.

Oxygenation & Ventilation

Following ROSC , it has been common practice to place all patients on 100% FiO2. However, there has been mounting evidence to suggest that hyperoxia may be deleterious. Specifically, a recent study by Kilgannon et al. that evaluated more than 6,000 adult patients following ROSC found that hyperoxia was independently associated with worsened outcome when compared to normoxia or hypoxia. Although the data from this study was not available prior to the publication of the AHA guidelines, it does add additional support for the avoidance of hyperoxic exposure in these patients. Therefore, until further data suggests otherwise, it is recommend that supplemental oxygen be titrated as soon as possible to maintain a SpO2 ≥ 94% but < 100% with a PaO2 of approximately 100mm Hg, while maintaining normocarbia.

Hemodynamic Optimization

Early hemodynamic optimization is an essential part of post-cardiac arrest care and focuses on restoring intravascular volume and maintenance of adequate perfusion pressure. Isotonic crystalloid should be administered to restore volume status and optimize rightheart- filling pressures. Mean arterial pressure (MAP), rather than systolic blood pressure (SBP) should be used as an endpoint, as this provides a better physiologic surrogate of perfusion. The ideal MAP following ROSC is not known; however, based on the current literature a MAP of 65-100mm Hg is considered reasonable. If this cannot be done with fluid alone, vasopressor and inotropic agents should be added. If an adequate perfusion pressure is still not achieved despite fluids, vasopressors and inotropes, an intra-aortic balloon pump or ventricular assist device can be considered.

Neuroprotection: Therapeutic Hypothermia

At present, knowledge gaps exist regarding the appropriate patient selection for the initiation of TH. This is primarily due to a paucity of literature regarding its effects on outcome in patients presenting with non-shockable rhythms (i.e., PEA or asystole). However, there appears to be the potential for benefit based on the data that is available. Therefore, current guidelines recommend the use of TH on all patients who remain comatose following ROSC . Patients should be cooled to a target temperature of 32-34°C, though the ideal temperature is still not known. Patients can be cooled in a variety of methods, and no data at present demonstrates a superior technique. This article does cover rewarming, however, given rewarming rarely occurs in the ER it is not discussed further in this review. The complications of TH include bradycardia, increased systemic vascular resistance, decreased cardiac output, induced diuresis resulting electrolyte disturbances, hyperglycemia and coagulopathy.

Management of Acute Coronary Syndrome

Coronary artery disease is a major cause of out-of-hospital cardiac arrest (OOHCA). Cardiac catheterization provides definitive therapy for patients with an acute occlusion and has been independently associated with improved outcome following ROSC . ST-segment elevation on electrocardiogram (ECG) is a poor predictor of acute arterial occlusion in this patient population. Therefore, all patients with a presumed cardiac etiology of arrest should be considered for emergent cardiac catheterization, even in the absence of ST-segment elevation. If PCI is not immediately available and ST-segment elevation is present, thrombolytic therapy should be considered. The potential interaction between thrombolytics and TH has not been established. On the other hand, PCI should not be delayed or withheld because of the use of TH, which has been demonstrated to be safe and effective.

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