Optimizing Survival Outcomes for Adult Patients with Nontraumatic Cardiac Arrest (Pharmacology CME)

Table of Contents

 

1. Abstract
2. Case Presentations
3. Introduction
4. Critical Appraisal of the Literature
5. Etiology And Pathophysiology
6. Differential Diagnosis
7. Prehospital Care
8. Emergency Department Evaluation
9. Diagnostic Studies
10. Treatment
    1. Basic Life Support
       1. Chest Compression Rate Goal: 100-120 compressions/min
       2. Chest Compression Depth Goal: 2 to 2.4 inches
       3. Chest Compression Fraction Goal: > 60% Of Resuscitation Time
       4. Allow Full Chest Wall Recoil Between Compressions
       5. Avoid Excessive Ventilation
       6. Defibrillation
    2. Airway Management And Ventilation
    3. Vascular Access
    4. Pharmacologic Interventions
       1. Vasopressors
       2. Antiarrhythmics
       3. Other Drugs
    5. Immediate Postarrest Care In The Emergency Department
       1. Pharmacologic Interventions
       2. Hemodynamic Management
       3. Targeted Temperature Management
    6. Prognostic Indicators Of Outcome
       1. End-Tidal Carbon Dioxide
       2. Ultrasound
       3. Termination Of Resuscitation
11. Special Circumstances
    1. Pregnancy
    2. Pulmonary Embolism
    3. Opioid Overdose
    4. Torsades de Pointe
    5. Patients With Other Toxicologic Causes Of Arrest
    6. Hyperkalemia
    7. Accidental Hypothermia
12. Controversies And Cutting Edge
    1. Percutaneous Coronary Interventions
    2. Extracorporeal Cardiopulmonary Resuscitation
    3. Steroids
13. Disposition
14. Summary
15. Risk Management Pitfalls For Cardiac Arrest
16. Time- And Cost-Effective Strategies
17. Case Conclusions
18. Clinical Pathway For Management Of Cardiac Arrest In The Emergency Department
19. Tables and Figures
    1. Table 1. The Hs And Ts In Pulseless Electrical Activity
    2. Table 2. Physical Examination Findings And Possibly Related Causes Of Arrest
    3. Figure 1. Electrocardiogram Of Ventricular Fibrillation
    4. Figure 2. Electrocardiogram Of Ventricular Tachycardia
    5. Figure 3. Electrocardiogram Of Torsades de Pointe
20. References

Abstract

Patient survival after cardiac arrest can be improved significantly with prompt and effective resuscitative care. This systematic review analyzes the basic life support factors that improve survival outcome, including chest compression technique and rapid defibrillation of shockable rhythms. For patients who are successfully resuscitated, comprehensive postresuscitation care is essential. Targeted temperature management is recommended for all patients who remain comatose, in addition to careful monitoring of oxygenation, hemodynamics, and cardiac rhythm. Management of cardiac arrest in circumstances such as pregnancy, pulmonary embolism, opioid overdose and other toxicologic causes, hypothermia, and coronary ischemia are also reviewed.

Case Presentations

Shortly after starting your night shift, you get STAT paged to bed 34. You rush to the room and find the nurses giving chest compressions. You wrack your brain to remember sign-out – wasn’t this the man who came in with chest pain, no ECG changes, but a concerning history? He was stable, just waiting on an inpatient bed! Not anymore, you sigh. You hold compressions to take a look at the monitor, and see V-fib. “Charge to 200 joules,” you say. “Clear!” calls the tech. The patient jumps with the force of the electricity. The nurse resumes compressions, but a few moments later, the patient moans, moving his hand to his chest. As you hold on compressions and continue to stabilize the patient, you wonder if he would be a good candidate to go to the cath lab . . .

Shortly afterward, you get a call from paramedics about a young man who collapsed suddenly while dancing at a nightclub. “He’s in full cardiac arrest,” they say, and you rush back to the critical care bay. You arrive in the resuscitation bay just as EMS arrives. “It’s V-fib,” the paramedic tells you. “He got 1 shock on the way over, and we’re due for a rhythm check now. EMS had them doing CPR at the scene, and they were doing a pretty good job. It’s only been about 10 minutes since the 911 call– the club is right around the corner from here.” You pause CPR and glance at the monitor. It’s still V-fib, so you deliver a shock at 200 joules and one of the nurses takes over CPR. “Great compressions,” you tell him, and you mean it - just the right depth and rate, and no pauses for nonsense. “I’ve got access, Doc,” says the technician. “Perfect,” you respond, “let’s give a milligram of epi.” You sound like you’re in control, but your mind is racing Why V-fib in a seemingly healthy young man?

Introduction

Cardiac arrest refers to the abrupt cessation of effective mechanical function of the heart. It may be caused by a variety of cardiac and noncardiac diseases.¹ There are more than half a million adult cardiac arrests in the United States each year, with approximately 325,000 outside the hospital and 200,000 in the hospital. There is a slight male predominance, with 57% of cases occurring in men.² Cardiac arrest occurs in all age groups, though incidence increases with age.²

Survival to hospital discharge occurs in approximately 10% of out-of-hospital arrest cases overall, though survival rates are more than 30% for bystander-witnessed cases.³ In-hospital arrest survival is approximately 20%,^4,5 though this estimate varies substantially by hospital⁶ and time of arrest.⁷ The presenting cardiac rhythm is an important predictor of outcome in cardiac arrest. The first documented rhythm is ventricular fibrillation (VF) in 17% of cases, ventricular tachycardia (VT) in 7%, pulseless electrical activity (PEA) in 37%, and asystole in 39%.⁸

Survival to hospital discharge is better overall for shockable rhythms, with more than 33% of patients surviving VF/VT arrests compared to approximately 10% for PEA and asystole.^8,9

Critical Appraisal Of The Literature

The body of literature on cardiac arrest is vast, with more than 40,000 articles in PubMed. Fortunately, the International Liaison Committee on Resuscitation (ILCOR) regularly reviews the literature and synthesizes it into practice guidelines for its member organizations, including the American Heart Association (AHA). The AHA publishes guideline updates every 5 years, and these are the “gold standard” in cardiac arrest science. The guidelines summarize clinical resuscitation protocols and their evidentiary basis, as well as noting areas where scientific evidence is lacking. The 2015 updates, published on October 15, 2015 in the journal Circulation, served as the starting point for this review, with additional targeted literature searches performed to address specific clinical questions.

The 2015 AHA guidelines emphasize the importance of immediate, continuous, high-quality cardiopulmonary resuscitation (CPR) and early defibrillation, while recognizing the relative paucity of evidence supporting more “advanced” interventions. Key points from the 2015 guidelines include the following:¹⁰

• Prehospital care
  • Expansion of recommendations for emergency medical services (EMS) dispatchers to instruct bystanders in compression-only CPR for all cases of suspected cardiac arrest
• Basic life support (BLS)
  • Continuation of emphasis on all aspects of CPR quality, especially rate and depth of chest compressions, as these are the most common errors made by CPR providers
  • Addition of an upper limit for chest compression rate (100-120/min)
  • Addition of an upper limit for chest compression depth (2-2.4 in)
  • Emphasis on decreasing preshock pauses in chest compressions
  • Addition of a specific goal for chest compression fraction (> 60% of total resuscitation time)
• Advanced/hospital-based life support
  • Continued recommendation that healthcare workers provide both compressions and breaths for all arrest victims, regardless of etiology
  • Addition of specific respiratory rate after intubation (1 breath/6 sec)
  • Recommendation to maximize inspired oxygen during resuscitation
  • Recognition of the potential utility of ultra sound, with the caveat that it must not interfere with CPR or defibrillation
  • Removal of vasopressin from arrest algorithms
  • Addition of rhythm-specific guidelines for timing of epinephrine
    • Shockable rhythm: after defibrillation, as this is the first priority
• Nonshockable rhythm: as soon as possible
• Postarrest care
  • Recommendation to consider percutaneous coronary interventions (PCI) in all successfully resuscitated arrest patients with suspected coronary syndromes
  • Recommendation for targeted temperature management at 32°C-36°C for at least 24 hours postarrest
  • Recommendation to avoid prognostication of neurologic outcome until 72 hours after return of spontaneous circulation

Risk Management Pitfalls For Cardiac Arrest

1. “I followed the guidelines – how was I supposed to know why he was in PEA?”
   PEA is often caused by noncardiac conditions, and will resolve only when these underlying conditions are treated. Standard resuscitation interventions do not resolve physiologic derangements causing PEA, and should be viewed as a bridge to more definitive care. Know the Hs and the Ts, and hunt for the root cause of PEA in every patient.
    
2. “I was busy intubating – it’s not my fault that chest compressions were too slow.”
   Chest compressions are the single most important intervention in cardiac arrest regardless of etiology, whereas intubation is not necessary in the majority of cases. Physicians must be meticulous about every aspect of compression quality. Compression rate can be monitored using the CPR quality feedback features available on many modern defibrillators, a metronome or timer, or even by singing (“Stayin’ Alive” has just the right tempo).
    
3. “I couldn’t compress any deeper – I was too tired!”
   Achieving adequate compression depth is physically challenging for many rescuers, and as fatigue worsens, compressions suffer. Physicians must monitor their team members for signs of fatigue and change compressors as needed to ensure quality CPR.
    
4. “I had no idea we stopped compressions for so long – I was having trouble getting a decent image on the ultrasound.”
   Low chest compression fraction contributes to poor survival outcomes, and needless pauses in CPR are not to be tolerated. In cardiac arrest, nothing is more important than CPR, and compressions should be halted only for scheduled breaths and rhythm checks/ defibrillation. The guidelines specifically stipulate that ultrasound should not be allowed to interfere with CPR.
    
5. “That monitor tracing was really weird – I didn’t realize it was V-tach.”
   Defibrillation is the only effective treatment for VF/VT arrest, and it is essential for clinicians to recognize these rhythms rapidly and reliably. While manual defibrillation mode is preferred for clinicians, automated mode may be used in the face of uncertainty about the rhythm.
    
6. “I knew it was V-fib, but I couldn’t get the blasted defibrillator hooked up! It’s the tech’s job anyway.”
   It is common practice to delegate defibrillation to nursing staff, and physicians may run dozens of resuscitations without ever touching the defibrillator, leading to skill decay. As leaders, physicians must be the most competent members of the resuscitation team, and should thoroughly understand operation of lifesaving equipment like the defibrillator.
    
7. “Sure, I didn’t ventilate – but everyone knows that chest compressions are the only thing that matters!”
   Emphasis on the importance of CPR and defibrillation has led to a misconception that respiratory support is irrelevant. While “hands-only” CPR is acceptable for lay rescuers, health professionals must provide ventilation along with chest compression in all resuscitations. Advanced airway placement is not mandatory, but effective ventilation is. Every breath should produce visible chest rise, and compressions should be coordinated with ventilations in a 30:2 ratio prior to advanced airway placement.
    
8. “So I gave a few doses of sodium bicarbonate – what’s wrong with that?”
   The only drugs that are included in resuscitation algorithms are epinephrine (all rhythms) and amiodarone (VF/VT – lidocaine is an acceptable alternative). Unless the patient has a specific indication for bicarbonate, such as hyperkalemia or tricyclic antidepressant overdose, this drug is not warranted and may be harmful.
    
9. “I got him back – it’s not my fault that he’s febrile.”
   Targeted temperature management in the range of 32ºC to 36ºC is required for a minimum of 24 hours following successful resuscitation from cardiac arrest. Fever is common in the postresuscitation period, and is known to be deleterious to outcomes, so temperature control must be meticulous.
    
10. “Her ECG looked OK – how was I supposed to know this was a STEMI?”
    Acute coronary syndromes are common among cardiac arrest patients, and the ECG is not reliable for diagnosing coronary ischemia in the postarrest period. Cardiac catheterization should be initiated for all successfully resuscitated patients with a suspected cardiac etiology of arrest.

Tables And Figures

References

Evidence-based medicine requires a critical appraisal of the literature based upon study methodology and number of subjects. Not all references are equally robust. The findings of a large, prospective, randomized, and blinded trial should carry more weight than a case report.

To help the reader judge the strength of each reference, pertinent information about the study is included in bold type following the reference, where available. In addition, the most informative references cited in this paper, as determined by the authors, are noted by an asterisk (*) next to the number of the reference.

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