7/6/23, 11:24 AM Advanced cardiac life support (ACLS) in adults - UpToDate Official reprint from UpToDate www.uptodate.com 2023 UpToDate, Inc. and/or its affiliates. All Rights Reserved. Advanced cardiac life support (ACLS) in adults : Jonathan Elmer, MD, MS, FNCS : Ron M Walls, MD, FRCPC, FAAEM, Richard L Page, MD : Jonathan Grayzel, MD, FAAEM All topics are updated as new evidence becomes available and our peer review process is complete. Literature review current through: Jun 2023. This topic last updated: Mar 27, 2023. INTRODUCTION The field of resuscitation has advanced over more than two centuries [1]. The Paris Academy of Science recommended mouth-to-mouth ventilation for drowning victims in 1740 [2]. In 1891, Dr. Friedrich Maass performed the first documented chest compressions on humans [3]. The American Heart Association (AHA) formally endorsed cardiopulmonary resuscitation (CPR) in 1963, and by 1966 they had adopted standardized CPR guidelines for instruction to lay rescuers [2]. Advanced cardiac life support (ACLS) guidelines have evolved over the past several decades based on a combination of scientific evidence of variable strength and expert consensus. The AHA and European Resuscitation Council developed the most recent ACLS Guidelines in 2020 and 2021, respectively, using the comprehensive review of resuscitation literature performed by the International Liaison Committee on Resuscitation (ILCOR) [4-6]. Guidelines are reviewed continually, with formal updates published periodically in the journals Circulation and Resuscitation. This topic will discuss the management of cardiac arrhythmias in adults as generally described in the most recent iteration of the ACLS Guidelines. Where our suggestions differ or expand upon the published guidelines, we state this explicitly. The evidence supporting the published guidelines is presented separately, as are issues related to basic life support (BLS), airway management, post-cardiac arrest management, pediatric resuscitation, and controversial treatments for cardiac arrest patients. https://www.uptodate.com/contents/advanced-cardiac-life-support-acls-in-adults/print 1/52 7/6/23, 11:24 AM Advanced cardiac life support (ACLS) in adults - UpToDate Basic resuscitation (see "Adult basic life support (BLS) for health care providers" and "Basic airway management in adults") Airway management (see "Overview of advanced airway management in adults for emergency medicine and critical care" and "Extraglottic devices for emergency airway management in adults" and "Rapid sequence intubation in adults for emergency medicine and critical care" and "Emergency cricothyrotomy (cricothyroidotomy)") Post-resuscitation care (see "Initial assessment and management of the adult post-cardiac arrest patient" and "Intensive care unit management of the intubated post-cardiac arrest adult patient") Resuscitation in specific settings (see "Accidental hypothermia in adults" and "Drowning (submersion injuries)" and "Electrical injuries and lightning strikes: Evaluation and management" and "Initial management of the critically ill adult with an unknown overdose" and "Anaphylaxis: Emergency treatment") Pediatric resuscitation (see "Pediatric basic life support (BLS) for health care providers" and "Pediatric advanced life support (PALS)" and "Basic airway management in children") Evidence and non-standard treatments (see "Supportive data for advanced cardiac life support in adults with sudden cardiac arrest" and "Therapies of uncertain benefit in basic and advanced cardiac life support") RESUSCITATION OF PATIENTS WITH COVID-19 Interim guidance for the performance of cardiopulmonary resuscitation (CPR) in patients with suspected or confirmed coronavirus disease 2019 (COVID-19)-related illness was first published by the American Heart Association (AHA) in 2020 and updated in 2021 [7,8]. This guidance and associated algorithms for basic life support (BLS) and ACLS can be accessed using the following graphic and reference ( algorithm 1) [8]. Original and updated guidance emphasizes several key points: Vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) offers significant protection to health care providers, including those involved in resuscitation of patients with suspected or confirmed COVID-19. Don personal protective equipment (PPE) according to local guidelines and availability. https://www.uptodate.com/contents/advanced-cardiac-life-support-acls-in-adults/print 2/52 7/6/23, 11:24 AM Advanced cardiac life support (ACLS) in adults - UpToDate Providers must follow local guidelines for use of PPE to protect against SARS-CoV-2 infection. We prefer rescuers use an N95 mask or its equivalent and eye protection because of the risk of aerosolization of virus from chest compressions, positive-pressure ventilation, and intubation. Because providers with surgical or procedural masks may initiate chest compressions, these providers should be relieved as soon as possible by personnel with higher-level PPE. Airway management, including bag-valve-mask (BVM) ventilation, should be delayed until all providers have donned appropriate PPE [9]. Minimize the number of clinicians performing resuscitation; use a negative-pressure room whenever possible; keep the door to the resuscitation room closed if possible. May use a mechanical device, if resources and expertise are available, to perform chest compressions on adults and on adolescents who meet minimum height and weight requirements. Use a high-efficiency particulate air (HEPA) filter for BVM and mechanical ventilation as soon as it is available. A single responder can perform defibrillation or initiate chest compressions while a patient is prone. Provided the patient is intubated, chest compressions can be accomplished by pushing on the chest wall behind the heart with the hands centered over the T7-T10 vertebral bodies. This approach is likely to be less effective than chest compressions in a supine patient with a compression board in place. We recommend patients be repositioned in a supine position and placed on a compression board as soon as sufficient personnel with appropriate PPE are available. EVIDENCE-BASED GUIDELINES Because of the nature of resuscitation research, few randomized controlled trials have been completed in humans. Many of the recommendations in the Guidelines for ACLS and subsequent updates published jointly by the American Heart Association (AHA) and the International Liaison Committee on Resuscitation (ILCOR), hereafter referred to as the ACLS Guidelines, are made based upon observational studies, animal studies, and expert consensus [4-6]. Guideline recommendations are classified according to the GRADE system [10]. The evidence supporting the ACLS Guidelines is reviewed in detail separately. (See "Supportive data for advanced cardiac life support in adults with sudden cardiac arrest".) PRINCIPLES OF MANAGEMENT https://www.uptodate.com/contents/advanced-cardiac-life-support-acls-in-adults/print 3/52 7/6/23, 11:24 AM Advanced cardiac life support (ACLS) in adults - UpToDate Excellent basic life support and its importance Excellent cardiopulmonary resuscitation (CPR) and early defibrillation for appropriately shockable arrhythmias remain the cornerstones of basic life support (BLS) and ACLS [4,5,11-14]. Although iterative updates for the ACLS Guidelines have suggested a number of revisions, including medications and monitoring, the emphasis on timely, excellent CPR and its critical role in resuscitative efforts remains unchanged ( algorithm 2 and algorithm 3) [15,16]. The most recent versions of the ACLS algorithms can be accessed online here. We emphasize the term "excellent CPR" because anything short of this standard does not achieve adequate cerebral and coronary perfusion, thereby compromising a patient's chances for neurologically intact survival. CPR is discussed in detail separately; key principles in the performance of ACLS are summarized in the following table ( table 1). (See "Adult basic life support (BLS) for health care providers".) Studies in both the in-hospital and prehospital settings demonstrate that chest compressions are often performed incorrectly, inconsistently, and with excessive interruption [17-21]. To be effective, chest compressions must be of sufficient depth (5 to 6 cm, or 2 to 2.5 inches) and rate (between 100 and 120 per minute) and must allow for complete recoil of the chest between compressions. Chest compression fraction, the proportion of total CPR time during which chest compressions are delivered, should be above 80 percent. In the past, clinicians frequently interrupted CPR to check for pulses, perform tracheal intubation, or obtain venous access. Current ACLS Guidelines strongly recommend that every effort be made not to interrupt CPR; interventions that have not been shown to improve outcomes, including tracheal intubation, venous access, and administration of medications to treat arrhythmias are carried out while CPR is performed. If the airway is obstructed, immediate management must be initiated and may necessitate interruption of compressions. (See "Airway foreign bodies in adults", section on 'Life-threatening asphyxiation' and "Emergency cricothyrotomy (cricothyroidotomy)".) A single biphasic defibrillation shock remains the recommended treatment for ventricular fibrillation (VF) or pulseless ventricular tachycardia (VT). CPR should be performed until the defibrillator is charged and resumed immediately after the shock is given, without pausing to recheck a pulse [22,23]. Assessment of waveform end-tidal carbon dioxide (EtCO ) may be used 2 as an adjunct to pulse checks if the patient is intubated (receiving asynchronous ventilation); however, further study of its reliability is needed. Interruptions in CPR (eg, for subsequent attempts at defibrillation) should occur no more frequently than every two minutes and for the shortest possible duration. Compressions are paused briefly for ventilation when using a bag- https://www.uptodate.com/contents/advanced-cardiac-life-support-acls-in-adults/print 4/52 7/6/23, 11:24 AM Advanced cardiac life support (ACLS) in adults - UpToDate valve-mask (BVM) ventilation device at a ratio of 30:2. (See "Carbon dioxide monitoring (capnography)", section on 'Effectiveness of CPR'.) There is a delay between the return of an organized electrical rhythm and effective myocardial contractions [24]. Thus, post-defibrillation pulse and rhythm checks are performed after two minutes of additional CPR or potentially in the brief pause while ventilations are being administered. Key elements in the performance of manual defibrillation are described in the following table ( table 2). Patients are often overventilated during resuscitation, resulting in excessive intrathoracic pressure, which can compromise venous return and result in reduced cardiac output and inadequate cerebral and cardiac perfusion. Delivery of 30 compressions followed by two rescue breaths is recommended in patients without an advanced airway in place. ACLS Guidelines advise asynchronous ventilations at 8 to 10 per minute if an endotracheal tube or extraglottic airway is in place, while continuous chest compressions are performed simultaneously [25]. In contrast to ACLS, we believe 6 to 8 appropriate tidal volume ventilations per minute by bag with supplemental oxygen are likely sufficient in the low-flow state of cardiac arrest and prevent excessive intrathoracic pressure [26]. Resuscitation team management A growing body of literature demonstrates that employing the principles of Crisis Resource Management (CRM), adapted from the aviation industry and introduced into medical care by anesthesiologists, decreases disorganization during resuscitation and improves patient care [27-30]. A primary goal of CRM is to access the collective knowledge and experience of the team in order to provide the best care possible and to compensate for oversights or other challenges that any individual is likely to experience during such stressful events. Training in these principles to improve the quality of ACLS performed by health care clinicians is feasible and recommended [31,32]. Two principles provide the foundation for CRM: leadership and communication [29]. Resuscitations usually involve health care providers from different disciplines, sometimes from different areas of an institution, who may not have worked together previously. Under these circumstances, role clarity can be difficult to establish. In CRM, it is imperative that one person assumes the role of team leader [29]. This person is responsible for the global management of the resuscitation, including ensuring that all required tasks are carried out competently, assigning specific team members their responsibilities, incorporating new information and coordinating communication among all team members, developing and implementing management strategies that will maximize patient outcome, and reassessing performance throughout the resuscitation. Many clinical systems pre-determine the leader for hospital resuscitation ( code ) teams. https://www.uptodate.com/contents/advanced-cardiac-life-support-acls-in-adults/print 5/52 7/6/23, 11:24 AM Advanced cardiac life support (ACLS) in adults - UpToDate The team leader must avoid performing technical procedures, as performance of a task inevitably shifts attention from the primary leadership responsibilities. In circumstances where staff expertise is limited, the team leader may be required to perform certain critical procedures. In these situations, leadership is specifically transferred to another clinician, if possible, or the team leader may be forced temporarily to perform both roles, although this compromises the ability to provide proficient leadership and assimilate new information. In CRM, communication is organized to provide effective and efficient care. All pertinent communication goes through the team leader, and the team leader shares important information with the team. When the team leader determines the need to perform a task, the request is directed to a specific team member, ideally by name. That team member verbally acknowledges the request and performs the task or, if unable to do so, informs the team leader that someone else should be assigned. Team members must be comfortable providing such feedback to the team leader. Specific emphasis is placed on the assigned team member repeating back medication doses and defibrillator energy settings to the team leader. This "closed-loop" communication leads to a more orderly transfer of information and is the appropriate standard for all communication during resuscitations. Though most decisions emanate from the team leader, a good team leader enlists the collective wisdom and experience of the entire team as needed. Team members must be encouraged to speak up if they have an observation, concern, or a feasible suggestion. Efforts should be made to overcome the tendency to withhold potentially lifesaving suggestions due to the fear of being incorrect or the nature of hierarchies that exist in many health care institutions. Extraneous personnel not directly involved with patient care are asked to leave to reduce noise and to ensure that orders from the leader and feedback from the resuscitation team can be heard clearly, and all non-critical verbalization must stop to ensure team harmony and clear communication. INITIAL MANAGEMENT AND ECG INTERPRETATION In the 2010 ACLS Guidelines, circulation assumed a more prominent role in the initial management of cardiac arrest, and this approach continues in subsequent iterations and updates. The "mantra" remains: circulation, airway, breathing (C-A-B). Once unresponsiveness is recognized, resuscitation begins by addressing circulation (excellent chest compressions), followed by airway opening, and then rescue breathing. In parallel, additional resources are mobilized by calling for help. Identifying a specific individual to call for help is more effective than a vague, general instruction for someone to do so. The ACLS Guidelines emphasize the importance of excellent, uninterrupted chest compressions and early defibrillation. Rescue https://www.uptodate.com/contents/advanced-cardiac-life-support-acls-in-adults/print 6/52 7/6/23, 11:24 AM Advanced cardiac life support (ACLS) in adults - UpToDate breathing is performed after the initiation of excellent chest compressions. Advanced airway management may be delayed if there is adequate rescue breathing without an advanced airway in place. (See 'Excellent basic life support and its importance' above and "Adult basic life support (BLS) for health care providers", section on 'Recognition of cardiac arrest'.) In the non-cardiac arrest situation, the other initial interventions for ACLS include administering oxygen (if the patient's oxygen saturation is measurable and below 94 percent), establishing vascular access, placing the patient on a cardiac and oxygen saturation monitor, and obtaining an electrocardiogram (ECG) [15,16,33]. Unstable patients must receive immediate care, even when data are incomplete or presumptive ( algorithm 2 and algorithm 3). The most recent versions of the ACLS algorithms can be accessed online here. Patients with ST elevation myocardial infarction (STEMI) on ECG should be prepared for rapid transfer to the catheterization laboratory, receive a thrombolytic (if not contraindicated), or be transferred to a center with percutaneous coronary intervention (PCI) capabilities. These decisions are made based on local resources and protocols. Stable patients require an assessment of their ECG to provide appropriate treatment consistent with ACLS Guidelines. Although it is best to make a definitive interpretation of the ECG prior to making management decisions, the settings in which ACLS Guidelines are commonly employed require a modified, empirical approach. Such an approach is guided by the following questions: Is the rhythm fast or slow? Are the QRS complexes wide or narrow? Is the rhythm regular or irregular? The answers to these questions often enable the clinician to make a provisional diagnosis and initiate appropriate therapy. AIRWAY MANAGEMENT In the minutes following sudden cardiac arrest, oxygen delivery is limited primarily by reduced blood flow, leading to the recommendation that excellent chest compressions take priority over ventilation during the initial resuscitation [4,6,11]. (See 'Principles of management' above.) Suggested approach to airway management while performing ACLS ACLS Guidelines support the use of a bag-valve-mask (BVM) device or placement of a supraglottic airway for ventilation during the initial management of sudden cardiac arrest unless one cannot ventilate the patient by these means or there is high certainty of rapid, successful placement of the https://www.uptodate.com/contents/advanced-cardiac-life-support-acls-in-adults/print 7/52 7/6/23, 11:24 AM Advanced cardiac life support (ACLS) in adults - UpToDate tracheal tube without interruption of chest compressions [34]. Generally, endotracheal intubation can be deferred until after return of spontaneous circulation (ROSC). The performance of BVM ventilation is described in detail separately. (See "Basic airway management in adults".) The ventilation rate is determined by whether the patient is intubated. If the patient is not intubated but ventilated using a BVM, the compression to ventilation ratio is 30:2. Although rescuers may be tempted to deliver non-synchronized BVM ventilations during cardiopulmonary resuscitation (CPR) to minimize interruptions in compressions, the mechanics of mask ventilations make it impossible to deliver adequate tidal volume during an active compression. If the patient is intubated, we suggest performing no more than 6 to 8 non-synchronized ventilations per minute (the ACLS Guidelines recommend 10 breaths per minute with an advanced airway in place; we believe fewer breaths are adequate). Tidal volumes of approximately 600 mL delivered in a controlled fashion such that chest rise occurs over no more than one second is recommended in the ACLS Guidelines. (See "Adult basic life support (BLS) for health care providers", section on 'Ventilations'.) Overzealous ventilation (excess volume and/or frequency) elevates intrathoracic pressure, thereby decreasing venous return, ventricular filling, and stroke volume with compressions; all of which result in inadequate cerebral perfusion. In addition, overventilation can cause gastric inflation, which increases the risk of regurgitation and aspiration. As a standard bag-valve-mask for adults has a volume of 1000 to 1500 mL, even if some air is lost to the environment, a full squeeze of the bag during ventilation is unnecessary to deliver 600 mL. Techniques and technical considerations A blindly inserted extraglottic airway (eg, laryngeal mask airway, laryngeal tube, Combitube) can be placed without interrupting excellent chest compressions, provides adequate ventilation in most cases, and may reduce the risk of aspiration compared with BVM ventilation [35]. We believe that this is a reasonable approach, equal or superior to BVM ventilation. Extraglottic airways can be placed by basic providers, and are considered alternatives to BVM ventilation, whereas tracheal intubation is an advanced technique for providers with the requisite training. Extraglottic airways and tracheal intubation are discussed separately. (See "Extraglottic devices for emergency airway management in adults", section on 'Extraglottic airway devices' and "Direct laryngoscopy and endotracheal intubation in adults".) https://www.uptodate.com/contents/advanced-cardiac-life-support-acls-in-adults/print 8/52 7/6/23, 11:24 AM Advanced cardiac life support (ACLS) in adults - UpToDate If intubation is to be performed during cardiac arrest, it must be done by a trained provider, ideally require less than 10 seconds to complete, be performed without interruption of chest compressions, and occur only after all other essential resuscitative maneuvers have been initiated. Once performed, rescuers must avoid hyperventilation. If ventilation is inadequate using a BVM or an extraglottic airway (eg, upper airway obstruction), intubation can be attempted during ongoing chest compressions or deferred to the two-minute interval (after a complete cycle of CPR) when the resuscitator is already committed to stopping CPR for a rhythm check and possible defibrillation. If ventilation cannot be provided by BVM or an extraglottic airway because of apparent obstruction, the clinician must determine immediately whether arrest is due to upper airway obstruction and intervene as necessary. The ACLS Guidelines include the following additional recommendations about airway management during the performance of ACLS [36]: It is reasonable to provide 100 percent oxygen during CPR. In patients with ROSC, oxygen concentration is adjusted to maintain oxygen saturation above 94 percent. Hyperoxia may be harmful to patients and should be avoided. (See "Initial assessment and management of the adult post-cardiac arrest patient", section on 'Mechanical ventilation' and "Overview of the acute management of ST-elevation myocardial infarction", section on 'Therapies of unclear benefit'.) Cricoid pressure should not be applied during intubation. It may be useful for preventing gastric insufflation during BVM ventilation. These issues are discussed separately. (See "Rapid sequence intubation in adults for emergency medicine and critical care", section on 'Positioning and protection'.) Oropharyngeal and nasopharyngeal airways can improve the quality of BVM ventilation and should be used whenever possible. (See "Basic airway management in adults", section on 'Airway adjuncts'.) Continuous waveform capnography (performed in addition to clinical assessment) is recommended for both confirming and monitoring correct tracheal tube placement and for monitoring the quality of CPR and ROSC. If waveform capnography is not available, a non-waveform carbon dioxide (CO ) detector may be used in addition to clinical 2 assessment. (See "Carbon dioxide monitoring (capnography)", section on 'Clinical applications for intubated patients'.) Evidence concerning airway management https://www.uptodate.com/contents/advanced-cardiac-life-support-acls-in-adults/print 9/52 7/6/23, 11:24 AM Advanced cardiac life support (ACLS) in adults - UpToDate Randomized trials The optimal approach to airway management for victims of sudden cardiac arrest remains uncertain, but it is likely BVM ventilation or an extraglottic airway, which are equally effective as tracheal intubation, more rapidly placed, and require less training. In a randomized trial of BVM ventilation (1020 patients) versus tracheal intubation (1023 patients) for pre-hospital management of out-of-hospital cardiac arrest in France or Belgium between 2015 and 2017, the primary outcome (survival with favorable neurologic outcome at 28 days) was similar in the two groups (4.3 percent for BVM compared with 4.2 percent for tracheal intubation) [37]. The trial failed to meet the prespecified criteria for noninferiority. Ambulance teams in these countries include physicians with training in intubation, which is not common in many countries. In a multicenter cluster randomized trial of a supraglottic airway device (4886 patients) versus tracheal intubation (4410 patients) for pre-hospital airway management of out-of- hospital cardiac arrest in England between 2015 and 2017, the primary outcome (favorable neurologic outcome at hospital discharge or 30 days, or at three- or six-month follow-up) was similar between the two groups [38,39]. There were no differences in survival at 72 hours or at 30 days. However, initial ventilation success occurred more commonly in the supraglottic airway group (87 versus 79 percent). In a multicenter cluster-crossover trial of a laryngeal tube (1505 patients) versus tracheal intubation (1499 patients) for pre-hospital airway management of out-of-hospital cardiac arrest in the United States between 2015 and 2017, the primary outcome (72-hour survival) occurred significantly more often in patients randomized to receive the laryngeal tube (18 versus 15 percent) [40]. Survival to discharge and functionally favorable survival were also greater in the laryngeal tube group. In a network meta-analysis of eight randomized and three quasi-randomized trials involving just under 16,000 patients, no difference in survival or neurologic outcome was found among the three approaches to prehospital airway management: supraglottic airway, BVM ventilation, and tracheal intubation [35]. Supraglottic airway placement was associated with a higher rate of ROSC. Until additional data are available suggesting a clear improvement in patient-important outcomes from a particular ventilatory technique, BVM ventilation or placement of a supraglottic device (with close attention to avoiding overventilation) remains the preferred approach to airway management for cardiac arrest patients. (See 'Suggested approach to airway management while performing ACLS' above.) https://www.uptodate.com/contents/advanced-cardiac-life-support-acls-in-adults/print 10/52 7/6/23, 11:24 AM Advanced cardiac life support (ACLS) in adults - UpToDate Observational studies The results of two large observational studies suggest that endotracheal intubation is not the best approach for managing patients with sudden cardiac arrest: In a prospective nationwide Japanese study involving 649,359 patients with sudden out-of- hospital cardiac arrest, the rate of survival with a favorable neurologic outcome was significantly lower among those managed with advanced airway techniques compared with BVM (1.1 versus 2.9 percent; odds ratio [OR] 0.38, 95% CI 0.36-0.39) [41]. Higher rates of survival with a favorable neurologic outcome when using BVM persisted across all analyzed subgroups, including adjustments for initial rhythm, ROSC, bystander CPR, and additional treatments. A study drawing on data collected between 2000 and 2014 from the Get With the Guidelines - Resuscitation multicenter registry used a propensity-matched cohort to compare outcomes among intubated and non-intubated patients who sustained in- hospital cardiac arrest [42]. In this study, each of 43,314 patients intubated during the first 15 minutes of presentation following sudden cardiac arrest were matched with patients not intubated in the same minute. Rates of ROSC (57.8 versus 59.3 percent), survival (16.3 versus 19.4 percent), and survival with good functional outcome (10.6 versus 13.6 percent) were all lower among intubated patients, and this held true across all prespecified subgroup analyses. Although both of these studies have limitations due to their observational nature and may not be generalizable to all settings, their size and consistent findings across all subgroup analyses support their conclusions. MEDICATIONS USED DURING CPR Epinephrine Epinephrine is the only medication indicated in sudden cardiac arrest regardless of arrest rhythm. Epinephrine is a sympathomimetic catecholamine that binds alpha-1, alpha-2, beta-1, and beta-2 receptors. During cardiopulmonary resuscitation (CPR), epinephrine is administered to increase systemic vasomotor tone via alpha-1 agonism, thereby increasing diastolic blood pressure and coronary perfusion pressure. The ACLS Guidelines recommend epinephrine (1 mg intravenous [IV] or intraosseous [IO] every three to five minutes) be administered after two minutes of CPR in shockable rhythms after the first rescue shock is delivered. Some study results have raised doubts about the benefit of epinephrine [43-45]. In a randomized trial of 8014 patients who suffered out-of-hospital cardiac arrest, IV epinephrine https://www.uptodate.com/contents/advanced-cardiac-life-support-acls-in-adults/print 11/52 7/6/23, 11:24 AM Advanced cardiac life support (ACLS) in adults - UpToDate increased the rate of return of spontaneous circulation (ROSC) compared with placebo (36 versus 12 percent) but did not improve survival at 30 days (3.2 versus 2.4 percent) [43]. This trial did not standardize or measure post-arrest care, potentially attenuating the benefit from improved ROSC in the epinephrine group. Pending formal change to ACLS protocols, we suggest giving epinephrine in accordance with existing guidelines. Atropine Atropine is not recommended for the treatment of asystole or pulseless electrical activity. For symptomatic bradycardia, the initial dose of atropine is 1 mg IV. This dose may be repeated every three to five minutes to a total dose of 3 mg. (See 'Approach to bradycardia' below.). Amiodarone and lidocaine Evidence suggests that antiarrhythmic drugs provide little survival benefit in refractory ventricular tachycardia (VT) or ventricular fibrillation (VF) [4-6]. A randomized trial of 3026 patients with out-of-hospital VT/VF refractory to initial defibrillation compared IV or IO amiodarone, lidocaine, and placebo and found no differences in survival to hospital discharge or functionally favorable survival in the overall study population [46]. In patients with witnessed collapse, amiodarone or lidocaine resulted in improved survival compared with placebo (28 versus 28 versus 23 percent). The ACLS Guidelines state that antiarrhythmic drugs may be used in certain situations, but the recommended timing of administration is not specified. We suggest that antiarrhythmic drugs may be administered after a second unsuccessful defibrillation attempt in anticipation of a third shock, particularly among patients with witnessed arrest in whom time to administration may be shorter [47]. (See 'Refractory pulseless ventricular tachycardia or ventricular fibrillation' below.) When used, amiodarone (300 mg IV/IO bolus with a repeat dose of 150 mg IV as indicated) or lidocaine (1 to 1.5 mg/kg IV/IO bolus, then 0.5 to 0.75 mg/kg every 5 to 10 minutes) may be administered in VT/VF unresponsive to defibrillation, CPR, and epinephrine. Magnesium Magnesium sulfate (2 to 4 g IV/IO bolus followed by a maintenance infusion) is used to treat polymorphic VT consistent with torsade de pointes but is not recommended for routine use in adult cardiac arrest patients. (See 'Irregular wide complex' below and "Acquired long QT syndrome: Clinical manifestations, diagnosis, and management", section on 'Initial management'.) Other medications Vasopressin Outcomes of patients who receive vasopressin during CPR are not superior to those who receive epinephrine alone, so vasopressin administration is not recommended in the ACLS Guidelines [48]. Among patients who have suffered in-hospital https://www.uptodate.com/contents/advanced-cardiac-life-support-acls-in-adults/print 12/52 7/6/23, 11:24 AM Advanced cardiac life support (ACLS) in adults - UpToDate cardiac arrest, three randomized controlled trials support administration of vasopressin (20 IU IV with each dose of epinephrine) together with glucocorticoids (methylprednisolone 40 mg IV once) as an adjunct to standard CPR [49-51]. Across trials, addition of vasopressin and glucocorticoid to standard care increased the rate of ROSC but did not consistently result in improved survival or functionally favorable recovery. Vasopressin and glucocorticoid administration are not currently recommended by ACLS Guidelines but may be reasonable during resuscitation of in-hospital cardiac arrest. Calcium Calcium chloride has both vasopressor and inotropic effects but has not shown benefit when used to treat cardiac arrest. A randomized trial of calcium chloride versus placebo during resuscitation of out-of-hospital cardiac arrest was terminated early because of a trend towards reduced rates of ROSC in patients receiving calcium [52]. Calcium chloride (1g IV) should not be routinely administered during CPR but may be indicated in some special circumstances (eg, hyperkalemia, calcium-channel blocker toxicity). (See "Treatment and prevention of hyperkalemia in adults" and "Calcium channel blocker poisoning".) Sodium bicarbonate Sodium bicarbonate can mitigate acidosis and hyperkalemia that may incite or worsen during cardiac arrest. However, according to a meta-analysis of four randomized trials and 10 observational studies, routine sodium bicarbonate administration during CPR did not provide a benefit [53]. Selective use of sodium bicarbonate (50 to 100 mEq IV) may be reasonable when there is clinical suspicion or laboratory evidence of significant pre-existing metabolic acidosis or hyperkalemia. (See "Approach to the adult with metabolic acidosis", section on 'Overview of therapy' and "Bicarbonate therapy in lactic acidosis".) MANAGEMENT OF SPECIFIC ARRHYTHMIAS Immediate patient management is algorithmic and does not depend on cardiac rhythm, as detailed above. (See 'Initial management and ECG interpretation' above.) The potential sudden cardiac arrest victim is assessed for responsiveness, breathing, and presence of a pulse. For patients with effective respiration and a palpable pulse, treatment is determined by the ventricular rate (tachycardiac or bradycardia) and clinical assessment of overall stability. (See 'Arrhythmias with a pulse' below.) Pulseless patients are managed initially with cardiopulmonary resuscitation. Patients with pulseless ventricular tachycardia (VT) and ventricular fibrillation (VF) are defibrillated as https://www.uptodate.com/contents/advanced-cardiac-life-support-acls-in-adults/print 13/52 7/6/23, 11:24 AM Advanced cardiac life support (ACLS) in adults - UpToDate rapidly as possible. Additional clinical considerations are discussed in greater detail below. (See 'Pulseless patient in sudden cardiac arrest' below.) Pulseless patient in sudden cardiac arrest Pulseless ventricular tachycardia and ventricular fibrillation Pulseless VT and VF are non-perfusing rhythms emanating from the ventricles for which early identification is critical. Successful resuscitation of patients with VT/VF requires excellent cardiopulmonary resuscitation (CPR) and rapid defibrillation. The American Heart Association (AHA) algorithm for the management of cardiac arrest can be accessed here ( algorithm 3). The most recent versions of the ACLS algorithms can be accessed online here. Excellent CPR is performed without interruption until the rescuer is ready to perform early defibrillation and is continued until return of spontaneous circulation (ROSC) is achieved. Treatable underlying causes should be identified and managed as quickly as possible ( table 3) [36,54,55]. Agonal breathing or transient convulsive activity may accompany these dysrhythmias, and responders should not delay initiating CPR by misinterpreting these signs. Begin performing excellent chest compressions as soon as cardiac arrest is recognized and continue while the defibrillator is being attached. If a defibrillator is not immediately available, continue CPR until one is obtained. As soon as a defibrillator is available, attach it to the patient ( figure 1) and charge it while continuing CPR, then stop compressions to assess the rhythm and defibrillate if appropriate (eg, VT/VF is present). If asystole or pulseless electrical activity is present, continue CPR. If defibrillation is performed, resume CPR immediately and continue compressions until the next pulse and rhythm check two minutes later. (See "Supportive data for advanced cardiac life support in adults with sudden cardiac arrest", section on 'VF and pulseless VT'.) Decreased time to defibrillation improves the likelihood of successful conversion to a perfusing rhythm and patient survival. For the monitored patient who sustains a witnessed VT/VF arrest, if a defibrillator is immediately available and defibrillator pads are in place, immediately charge the defibrillator and deliver a shock. The 10 seconds or fewer of CPR that might have been applied prior to the shock are unlikely to have generated any meaningful perfusion. Biphasic defibrillators are recommended because of their increased efficacy at lower energy levels [56-58]. The ACLS Guidelines recommend that when employing a biphasic defibrillator clinicians use the initial dose of energy recommended by the manufacturer (120 to 200 J). If this dose is not known, the maximal dose may be used. We suggest a first defibrillation at maximal energy for VT/VF. If a monophasic defibrillator is used, 360 J is the appropriate energy dose for initial and subsequent shocks. https://www.uptodate.com/contents/advanced-cardiac-life-support-acls-in-adults/print 14/52 7/6/23, 11:24 AM Advanced cardiac life support (ACLS) in adults - UpToDate ACLS Guidelines recommend the resumption of CPR immediately after defibrillation without checking for a pulse. This recommendation is made because effective cardiac contractility lags restoration of an organized electrical rhythm. Clinicians should stop compressions to perform a rhythm check only after two minutes of CPR, and not before the defibrillator is fully charged if the rhythm is VT/VF. (See "Adult basic life support (BLS) for health care providers", section on 'Phases of resuscitation' and "Adult basic life support (BLS) for health care providers", section on 'Defibrillation'.)