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《心肺复苏指南》参考资料（英文版）Part 7-2 Management of Cardiac Arrest

Frhythms produce pulseless cardiac arrest: ventricular effective for fluid resuscitation, drug delivery, and blood fibrillation (VF), rapid ventricular tachycardia (VT), sampling for laboratory evaluation, and is attainable in all age useless electrical activity(PEA), and asystole. Surviva

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Part 7.2: Management of Cardiac Arrest F rhythms produce pulseless cardiac arrest: ventricular effective for fluid resuscitation, drug delivery, and blood fibrillation (VF), rapid ventricular tachycardia (VT), sampling for laboratory evaluation, and is attainable in all age useless electrical activity(PEA), and asystole. Surviva groups. Providers may establish I0 access if IV access is from these arrest rhythms requires both basic life support unavailable( Class IIa). Commercially available kits can (BLS) and advanced cardiovascular life support(ACLS) facilitate IO access in adults The foundation of ACLS care is good BLS care, beginning If spontaneous circulation does not return after defibrilla with prompt high-quality bystander CPR and, for VE/pulse- tion and peripheral venous or I0 drug administration, the less VT, attempted defibrillation within minutes of collapse. provider may consider placement of a central line(unless For victims of witnessed VF arrest, prompt bystander CPr there are contraindications ). Note that central venous cathe and early defibrillation can significantly increase the chance terization is a relative (not absolute) contraindication for for survival to hospital discharge. In comparison, typical fibrinolytic therapy in patients with stroke or acute coronary ACLS therapies, such as insertion of advanced airways and syndromes of the circulation have not be If iv and io access cannot be established. some resusci- shown to increase rate of survival to hospital discharge. This tation drugs may be administered by the endotracheal route section details the general care of a patient in cardiac arrest One study in children(LOE 2), 2 5 studies in adults(LOE and provides an overview of the ACLs Pulseless Arrest 213-15; LOE 316.1), as well as multiple animal studies(LOE 6), 8-20 showed that lidocaine, 14,2I epinephrine, 2 atropine, 23 naloxone, and vasopressin20 are absorbed via the trachea. Access for Medications: Correct Priorities dministration of resuscitation drugs into the trachea, how- During cardiac arrest, basic CPR and early defibrillation are ever, results in lower blood concentrations than the same dose of primary importance, and drug administration is of second- given intravascularly. Furthermore, recent animal studies24 ary importance. Few drugs used in the treatment of cardiac suggest that the lower epinephrine concentrations achieved arrest are supported by strong evidence. After beginning CPR when the drug is delivered by the endotracheal route may and attempting defibrillation, rescuers can establish intrave- produce transient B-adrenergic effects. These effects can be nous (Tv) access, consider drug therapy, and insert an detrimental, causing hypotension, lower coronary artery per dvanced airway. fusion pressure and flow, and reduced potential for return of Central Versus Peripheral Infusions spontaneous circulation (ROSC). Thus, although Central line access is not needed in most resuscitation cheal administration of some resuscitation drugs is attempts. If IV access has not been established, the provide IV or Io drug administration is preferred because should insert a large peripheral venous catheter. Although in provide more predictable drug delivery and pharmacologic effect adults peak drug concentrations are lower and circulation times longer when drugs are administered via peripheral sites In one nonrandomized cohort study of out-of-hospital cardiac arrest in adults (loe 4)28 using a randomized control rather than central sites, the establishment of peripheral administration of atropine and epinephrine by the IV route access does not require interruption of CPR. .2 Drugs typi cally require I to 2 minutes to reach the central circulation was associated with a higher rate of rosc and survival to when given via a peripheral vein but require less time when hospital admission than administration of the drugs by the endotracheal route. Five percent of those who received Iv given via central venous access. venous route, administer the drug by bolus injection and in the group receiving drugs by the endotracheal roule ved If a resuscitation drug is administered by a peripheral drugs survived to hospital discharge, but no patient survived The optimal endotracheal dose of most drugs is unknown, follow with a 20-mL bolus of IV fluid Elevate the extremity but typically the dose given by the endotracheal route is 2 to for 10 to 20 seconds to facilitate drug delivery to the central irculation 3 21 times the recommended iv dose. In 2 CPR studies th Intraosseous(1O)cannulation provides access to a noncol- equipotent epinephrine dose given endotracheally was ap- lapsible venous plexus, enabling drug delivery similar to that proximately 3 to 10 times higher than the IV dose(LOE 52 achieved by central venous access. Two prospective(LOE 3) LOE 630). Providers should dilute the recommended dose in trials, in children and adults 5 and 6 other studies(LOE 46, 5 to 10 mL of water or normal saline and inject the drug LOE 57: LOE 710.1)documented that IO access is safe and directly into the endotracheal tube. 22 Studies with epineph- rine3I and lidocaine showed that dilution with water instead of 0.9%o saline may achieve better drug absorption (Circulation. 2005: 112: lV-58-IV-66) o 2005 American Heart Associa Arrest rhythms This special supplement to Circulation is freely available at The management of pulseless arrest is highlighted in the http://www.circulationaha.org ACLS Pulseless Arrest Algorithm(Figure). Box numbers in DOI: 10.1161/CIRCULATIONAHA 105. 166557 the text refer to the numbered boxes in the algorithm IV-58

Part 7.2: Management of Cardiac Arrest Four rhythms produce pulseless cardiac arrest: ventricular fibrillation (VF), rapid ventricular tachycardia (VT), pulseless electrical activity (PEA), and asystole. Survival from these arrest rhythms requires both basic life support (BLS) and advanced cardiovascular life support (ACLS). The foundation of ACLS care is good BLS care, beginning with prompt high-quality bystander CPR and, for VF/pulseless VT, attempted defibrillation within minutes of collapse. For victims of witnessed VF arrest, prompt bystander CPR and early defibrillation can significantly increase the chance for survival to hospital discharge. In comparison, typical ACLS therapies, such as insertion of advanced airways and pharmacologic support of the circulation, have not been shown to increase rate of survival to hospital discharge. This section details the general care of a patient in cardiac arrest and provides an overview of the ACLS Pulseless Arrest Algorithm. Access for Medications: Correct Priorities During cardiac arrest, basic CPR and early defibrillation are of primary importance, and drug administration is of secondary importance. Few drugs used in the treatment of cardiac arrest are supported by strong evidence. After beginning CPR and attempting defibrillation, rescuers can establish intravenous (IV) access, consider drug therapy, and insert an advanced airway. Central Versus Peripheral Infusions Central line access is not needed in most resuscitation attempts. If IV access has not been established, the provider should insert a large peripheral venous catheter. Although in adults peak drug concentrations are lower and circulation times longer when drugs are administered via peripheral sites rather than central sites, the establishment of peripheral access does not require interruption of CPR.1,2 Drugs typically require 1 to 2 minutes to reach the central circulation when given via a peripheral vein but require less time when given via central venous access. If a resuscitation drug is administered by a peripheral venous route, administer the drug by bolus injection and follow with a 20-mL bolus of IV fluid. Elevate the extremity for 10 to 20 seconds to facilitate drug delivery to the central circulation.3 Intraosseous (IO) cannulation provides access to a noncollapsible venous plexus, enabling drug delivery similar to that achieved by central venous access. Two prospective (LOE 3) trials, in children4 and adults,5 and 6 other studies (LOE 46; LOE 57–9; LOE 710,11) documented that IO access is safe and effective for fluid resuscitation, drug delivery, and blood sampling for laboratory evaluation, and is attainable in all age groups. Providers may establish IO access if IV access is unavailable (Class IIa). Commercially available kits can facilitate IO access in adults. If spontaneous circulation does not return after defibrillation and peripheral venous or IO drug administration, the provider may consider placement of a central line (unless there are contraindications). Note that central venous catheterization is a relative (not absolute) contraindication for fibrinolytic therapy in patients with stroke or acute coronary syndromes. If IV and IO access cannot be established, some resuscitation drugs may be administered by the endotracheal route. One study in children (LOE 2),12 5 studies in adults (LOE 213–15; LOE 316,17), as well as multiple animal studies (LOE 6),18–20 showed that lidocaine,14,21 epinephrine,22 atropine,23 naloxone, and vasopressin20 are absorbed via the trachea. Administration of resuscitation drugs into the trachea, however, results in lower blood concentrations than the same dose given intravascularly. Furthermore, recent animal studies24–27 suggest that the lower epinephrine concentrations achieved when the drug is delivered by the endotracheal route may produce transient -adrenergic effects. These effects can be detrimental, causing hypotension, lower coronary artery perfusion pressure and flow, and reduced potential for return of spontaneous circulation (ROSC). Thus, although endotracheal administration of some resuscitation drugs is possible, IV or IO drug administration is preferred because it will provide more predictable drug delivery and pharmacologic effect. In one nonrandomized cohort study of out-of-hospital cardiac arrest in adults (LOE 4)28 using a randomized control, administration of atropine and epinephrine by the IV route was associated with a higher rate of ROSC and survival to hospital admission than administration of the drugs by the endotracheal route. Five percent of those who received IV drugs survived to hospital discharge, but no patient survived in the group receiving drugs by the endotracheal route. The optimal endotracheal dose of most drugs is unknown, but typically the dose given by the endotracheal route is 2 to 21⁄2 times the recommended IV dose. In 2 CPR studies the equipotent epinephrine dose given endotracheally was approximately 3 to 10 times higher than the IV dose (LOE 529; LOE 630). Providers should dilute the recommended dose in 5 to 10 mL of water or normal saline and inject the drug directly into the endotracheal tube.22 Studies with epinephrine31 and lidocaine17 showed that dilution with water instead of 0.9% saline may achieve better drug absorption. Arrest Rhythms The management of pulseless arrest is highlighted in the ACLS Pulseless Arrest Algorithm (Figure). Box numbers in the text refer to the numbered boxes in the algorithm. (Circulation. 2005;112:IV-58-IV-66.) © 2005 American Heart Association. This special supplement to Circulation is freely available at http://www.circulationaha.org DOI: 10.1161/CIRCULATIONAHA.105.166557 IV-58

Part 7.2: Management of cardiac arrest / v-59 PULSELESS ARREST Artach monitordefibrillator when available Check rhythm Shockable rhythm? VE/T Asystole/PEA ve 1 shock Oie s eretes ef CPR May give 1 dose of vasopressin 40 U IAO to replace first or second dose of epin Consider atropine 1 mg Ino Shockable rhythm? Continue CPR while defibrillator is charging ve 1 shock Manual biphasic device specific AED: device specif ressor during CPR (before or after the shock Repeat every 3 to 5 min May give 1 dose of vasopressin 40 U no to replace first or second dose of epinephrine 12 l asystole, go to Box 10 13 e pulse. If no pulse, got Shockable rhythm? Continue CPA while dehbritator is charging nsure full chest recoil 2 minutes wth rhythm checks Manual biphasic: device specific Minimize interruptions in chest A D: device specific One cycle of CPR: 30 compressions Avoid hy it ation Secure airway and confirm placement consider addtional 150 m0 once, then w ANer an airway in placed (1 to 1.5 mg/kg first dose, then doses or 3 mo/ko) af CPR. Give continous ct ium, loading dose Thrombosis (coronary or Give B to 10 breathe/minute Check After 5 cycles of CPR, ' got to Box 5 above rhythm every 2 minutes ACLS Pulseless Arrest Algorithm. Ventricular fibrillation/Pulseless seconds, the provider should turn on the defibrillator, place Ventricular Tachycardia adhesive pads or paddles, and check the rhythm(Box 2) The most critical interventions during the first minutes of VF If the healthcare provider does not witness the arrest in the or pulseless VT are immediate bystander CPR (Box 1)with out-of-hospital setting (eg, the emergency medical services minimal interruption in chest compressions and defibrillation [EMS] provider arrives at the scene of an arrest), the provider as soon as it can be accomplished( Class D). In cases of may give 5 cycles of CPR before attempting defibrillation. In itnessed arrest with a defibrillator on-site, after delivery of adults with a prolonged arrest, shock delivery may be more 2 rescue breaths the healthcare provider should check for a successful after a period of effective chest pulse. If the provider definitely does not feel a pulse within 10 For further information about the sequence of CPR first

lV-60 Circulation December 13, 2005 versus shock first, see Part 5: " Electrical Therapies: Auto- rescuers to deliver shocks as efficiently as possible. Pulse and mated External Defibrillators, Defibrillation, Cardioversion, rhythm checks are limited and are not recommended imme diately after shock delivery; instead healthcare providers give If VF/pulseless VT is present(Box 3), providers shoul 5 cycles(about 2 minutes of CPR) immediately after the deliver I shock(Box 4)and then resume CPR immediately, shock and then check the rhythm. Ideally, compression beginning with chest compressions. If a biphasic defibrillator should be interrupted only for ventilation(until an adva is available, providers should use the dose at which that airway is placed), rhythm check, or shock delivery defibrillator has been shown to be effective for terminating Once an advanced airway (eg, endotracheal tube VF(typically a selected energy of 120 J to 200 D). If the esophageal-tracheal combitube [Combitube], laryngeal mask provider is unaware of the effective dose range of the device, airway [LMAD is placed, 2 rescuers no longer deliver cycles the rescuer may use a dose of 200 J for the first shock and of compressions interrupted with pauses for ventilation equal or higher shock dose for the second and subsequent Instead, the compressing rescuer should deliver 100 compres shocks. If a monophasic defibrillator is used, providers sions per minute continuously, without pauses for ventilation. should deliver an initial shock of 360 j and use that dose fo The rescuer delivering the ventilations should give 8 to 10 subsequent shocks. If VF is initially terminated by a shock breaths per minute and should be careful to avoid delivering but then recurs later in the arrest, deliver subsequent shocks at an excessive number of ventilations. Two or more rescuers the previously successful energy level. should rotate the compressor role approximately every 2 Biphasic defibrillators use a variety of waveforms, and minutes(when the victim's rhythm is checked). This change each waveform has been shown to be effective in terminating should prevent compressor fatigue and deterioration in qual VF over a specific dose range. Manufacturers should this effective waveform dose range on the face of the biphasic Establishing IV access is important(see below ) but it device, and providers should use that dose range to attempt should not interfere with CPR and delivery of shocks. As defibrillation with that device. The 200-J default "energy always, the provider should recall the H's and T's to identify level was selected because it falls within the reported range of a factor that may have caused the arrest or may be compli- selected doses that are effective for first and subsequent cating the resuscitative effort(see the green box, During biphasic shocks and can be provided by every biphasic CPR, "at the bottom of the algorithm) manual defibrillator available in 2005. This is a consensus There is inadequate evidence to identify an optimal number default dose and not a recommended ideal dose If biphasic of CPR cycles and defibrillation shocks that should be given devices are clearly labeled and providers are familiar with the before pharmacologic therapy is initiated. The recommended devices they use in clinical care, there will be no need for the sequence depicted in the algorithm is based on expert default 200-J dose. Ongoing research is necessary to firmly consensus. If VF/VT persists after delivery of I or 2 shocks establish the most appropriate initial settings for both plus CPR, give a vasopressor (epinephrine every 3 to 5 monophasic and biphasic defibrillators minutes during cardiac arrest: one dose of vasopressin may Providers should give I shock rather than the 3 successive replace either the first or second dose of epinephrine-se ("stacked")shocks recommended in previous versions of the Box 6). Do not interrupt CPR to give medications ECC guideliness for the treatment of VF/pulseless VT The drug should be administered during cpr and s Soon because the first-shock success rate for biphasic defibrillators as possible after the rhythm is checked. It can be administered is high 36 and it is important to minimize interruptions in chest before or after shock delivery, in a CPR-RHYTHM compressions. Although the l-shock strategy CHECK-CPR (while drug administered and defibrillator directly studied against a 3-shock strategy, the evidence is charged)SHOCK sequence(repeated as needed). This se compelling that interruption of chest compressions reduces quence differs from the one recommended in 200035:it coronary perfusion pressure. The time required to charge a designed to minimize interruptions in chest compressions. defibrillator, deliver a shock, and check a pulse can interrupt The 2000 recommendations In too many interrup- compressions for 37 seconds or longer 37(for further informa- tions in chest compressions. tion see Part 5:"Electrical Therapies: Automated External In these 2005 recommendations. during treatment of car- Defibrillators, Defibrillation, Cardioversion, and Pacing) diac arrest the drug doses should be prepared before the When a rhythm check reveals VF/VT, rescuers should rhythm check so they can be administered as soon as possible provide CPR while the defibrillator charges(when possible), after the rhythm check, but the timing of drug delivery is less until it is time to "clear"the victim for shock delivery. Give important than the need to minimize interruptions in chest the shock as quickly as possible. Immediately after shock compressions. Rhythm checks should be very brief(see delivery, resume CPR(beginning with chest compressions) below ). If a drug is administered immediately after the without delay and continue for 5 cycles (or about 2 minutes rhythm check(before or after the shock) it will be circulated if an advanced airway is in place), and then check the rhyth by the CPR given before and after the shock. After 5 cycles (Box 5). In in-hospital units with continuous monitoring(eg, (or about 2 minutes)of CPR, analyze the rhythm again(Box electrocardiography, hemodynamics), this sequence may be 7)and be prepared to deliver another shock immediately if modified at the physician's discretion(see Part 5) y. The management strategy depicted in the ACLS Pulseless When VF/pulseless VT persists after 2 to 3 shocks plus rest Algorithm is designed to minimize the number of CPR and administration of a vasopressor, consider adminis- times that chest ce ssions are interrupted and to enable tering an antiarrhythmic such as amiodarone (Box 8). If

versus shock first, see Part 5: “Electrical Therapies: Automated External Defibrillators, Defibrillation, Cardioversion, and Pacing.” If VF/pulseless VT is present (Box 3), providers should deliver 1 shock (Box 4) and then resume CPR immediately, beginning with chest compressions. If a biphasic defibrillator is available, providers should use the dose at which that defibrillator has been shown to be effective for terminating VF (typically a selected energy of 120 J to 200 J). If the provider is unaware of the effective dose range of the device, the rescuer may use a dose of 200 J for the first shock and an equal or higher shock dose for the second and subsequent shocks. If a monophasic defibrillator is used, providers should deliver an initial shock of 360 J and use that dose for subsequent shocks. If VF is initially terminated by a shock but then recurs later in the arrest, deliver subsequent shocks at the previously successful energy level. Biphasic defibrillators use a variety of waveforms, and each waveform has been shown to be effective in terminating VF over a specific dose range. Manufacturers should display this effective waveform dose range on the face of the biphasic device, and providers should use that dose range to attempt defibrillation with that device. The 200-J “default” energy level was selected because it falls within the reported range of selected doses that are effective for first and subsequent biphasic shocks and can be provided by every biphasic manual defibrillator available in 2005. This is a consensus default dose and not a recommended ideal dose. If biphasic devices are clearly labeled and providers are familiar with the devices they use in clinical care, there will be no need for the default 200-J dose. Ongoing research is necessary to firmly establish the most appropriate initial settings for both monophasic and biphasic defibrillators. Providers should give 1 shock rather than the 3 successive (“stacked”) shocks recommended in previous versions of the ECC guidelines35 for the treatment of VF/pulseless VT because the first-shock success rate for biphasic defibrillators is high36 and it is important to minimize interruptions in chest compressions. Although the 1-shock strategy has not been directly studied against a 3-shock strategy, the evidence is compelling that interruption of chest compressions reduces coronary perfusion pressure. The time required to charge a defibrillator, deliver a shock, and check a pulse can interrupt compressions for 37 seconds or longer37 (for further information see Part 5: “Electrical Therapies: Automated External Defibrillators, Defibrillation, Cardioversion, and Pacing”). When a rhythm check reveals VF/VT, rescuers should provide CPR while the defibrillator charges (when possible), until it is time to “clear” the victim for shock delivery. Give the shock as quickly as possible. Immediately after shock delivery, resume CPR (beginning with chest compressions) without delay and continue for 5 cycles (or about 2 minutes if an advanced airway is in place), and then check the rhythm (Box 5). In in-hospital units with continuous monitoring (eg, electrocardiography, hemodynamics), this sequence may be modified at the physician’s discretion (see Part 5). The management strategy depicted in the ACLS Pulseless Arrest Algorithm is designed to minimize the number of times that chest compressions are interrupted and to enable rescuers to deliver shocks as efficiently as possible. Pulse and rhythm checks are limited and are not recommended immediately after shock delivery; instead healthcare providers give 5 cycles (about 2 minutes of CPR) immediately after the shock and then check the rhythm. Ideally, compression should be interrupted only for ventilation (until an advanced airway is placed), rhythm check, or shock delivery. Once an advanced airway (eg, endotracheal tube, esophageal-tracheal combitube [Combitube], laryngeal mask airway [LMA]) is placed, 2 rescuers no longer deliver cycles of compressions interrupted with pauses for ventilation. Instead, the compressing rescuer should deliver 100 compressions per minute continuously, without pauses for ventilation. The rescuer delivering the ventilations should give 8 to 10 breaths per minute and should be careful to avoid delivering an excessive number of ventilations. Two or more rescuers should rotate the compressor role approximately every 2 minutes (when the victim’s rhythm is checked). This change should prevent compressor fatigue and deterioration in quality and rate of chest compressions. Establishing IV access is important (see below), but it should not interfere with CPR and delivery of shocks. As always, the provider should recall the H’s and T’s to identify a factor that may have caused the arrest or may be complicating the resuscitative effort (see the green box, “During CPR,” at the bottom of the algorithm). There is inadequate evidence to identify an optimal number of CPR cycles and defibrillation shocks that should be given before pharmacologic therapy is initiated. The recommended sequence depicted in the algorithm is based on expert consensus. If VF/VT persists after delivery of 1 or 2 shocks plus CPR, give a vasopressor (epinephrine every 3 to 5 minutes during cardiac arrest; one dose of vasopressin may replace either the first or second dose of epinephrine—see Box 6). Do not interrupt CPR to give medications. The drug should be administered during CPR and as soon as possible after the rhythm is checked. It can be administered before or after shock delivery, in a CPR–RHYTHM CHECK–CPR (while drug administered and defibrillator charged)–SHOCK sequence (repeated as needed). This sequence differs from the one recommended in 200035: it is designed to minimize interruptions in chest compressions. The 2000 recommendations resulted in too many interruptions in chest compressions. In these 2005 recommendations, during treatment of cardiac arrest the drug doses should be prepared before the rhythm check so they can be administered as soon as possible after the rhythm check, but the timing of drug delivery is less important than the need to minimize interruptions in chest compressions. Rhythm checks should be very brief (see below). If a drug is administered immediately after the rhythm check (before or after the shock) it will be circulated by the CPR given before and after the shock. After 5 cycles (or about 2 minutes) of CPR, analyze the rhythm again (Box 7) and be prepared to deliver another shock immediately if indicated. When VF/pulseless VT persists after 2 to 3 shocks plus CPR and administration of a vasopressor, consider administering an antiarrhythmic such as amiodarone (Box 8). If IV-60 Circulation December 13, 2005

Part 7.2: Management of Cardiac Arrest V-6I amiodarone available, lidocaine may be considered. should insert an advanced airway (eg, endotracheal tube Consider magnesium for torsades de pointes associated with Combitube, LMA). Once the airway is in place, 2 rescuers a long QT interval(see below). You should administer the should no longer deliver cycles of CPr(ie, compressions drug during CPR, as soon as possible after rhythm analysis. If interrupted by pauses when breaths are delivered). Instead the a nonshockable rhythm is present and the rhythm is organized compressing rescuer should give continuous chest compres- (complexes appear regular or narrow), try to palpate a pulse sions at a rate of 100 per minute without pauses for ventila tion. The rescuer delivering ventilation provides 8 to 10 Rhythm checks should be brief, and pulse checks should breaths per minute. The 2 rescuers should change compressor generally be performed only if an organized rhythm is and ventilator roles approximately every 2 minutes(when the observed. If there is any doubt about the presence of a pulse, rhythm is checked) to prevent compressor fatigue and dete- resume CPR. If the patient has ROSC, begin postresuscitation rioration in quality and rate of chest compressions. When care. If the patient's rhythm changes to asystole or PEA, see multiple rescuers are present, they should rotate the compres- Asystole and Pulseless Electrical Activity "below (Boxes 9 and sor role about every 2 minutes. Rescuers should minimize 10) interruptions in chest compressions while inserting the airway If a perfusing rhythm is transiently restored but not and should not interrupt CPR while establishing I or IO successfully maintained between repeated shocks(recurrent access VF/VT), the patient may be a candidate for early treatment If the rhythm check confirms asystole or PEA, resume CPR with antiarrhythmic medications(see Part 7.3: " Management immediately. A vasopressor (epinephrine or vasopressin) may of Symptomatic Bradycardia and Tachycardia") be administered at this time. Epinephrine can be administered During treatment of VF/pulseless VT, healthcare providers approximately every 3 to 5 minutes during cardiac arrest; or must practice efficient coordination between CPR and shock dose of vasopressin may be substituted for either the first or delivery. When VF is present for more than a few minutes, second epinephrine dose(Box 10). For a patient in asystole the myocardium is depleted of oxygen and metabolic sub- slow PEA, consider atropine(see below). Do not interrupt and energy substrates, increasing the likelihood that a possible after the rhythm check. Give the drug as soon as ng rhythm will return after shock delivery.38 Analyses After drug delivery and approximately 5 cycles(or about 2 waveform characteristics predictive of shock success minutes)of CPR, recheck the rhythm(Box 11). If a shockable have documented that the shorter the time between chest rhythm is present, deliver a shock(go to Box 4). If no rhythm compression and shock delivery, the more likely the shock is present or if there is no change in the appearance of the will be successful. 38,39 Reduction in the interval from com- electrocardiogram, immediately resume CPR(Box 10). If an pression to shock delivery by even a few seconds can increase organized rhythm is present(Box 12), try to palpate a pulse. he probability of shock If no pulse is present (or if there is any doubt about the presence of a pulse), continue CPR(Box 10). If a pulse is Asystole and Pulseless Electrical Activity(Box 9) present the provider should identify the rhythm and treat PEA encompasses a heterogeneous group of pulseless appropriately(see Part 7.3: " Management of Symptomatic rhythms that includes pseudo-electromechanical dissociation Bradycardia and Tachycardia"). If the patient appears to have (pseudo-EMD), idioventricular rhythms, ventricular escape an organized rhythm with a good pulse, begin postresuscita- rhythms, postdefibrillation idioventricular rhythms, and bra- dyasystolic rhythms Research with cardiac ultrasonography and indwelling pressure catheters has confirmed that pulse When Should Resuscitative Efforts Stop? less patients with electrical activity have associated mechan- The resuscitation team must make a conscientious and com- ical contractions, but these contractions are too weak to petent effort to give patients a trial of CPR and ACLS duce a blood detectable by palpation or nonin- provided that the patient has not expressed a decision to vasive blood pressure monitoring. PEA is often caused by forego resuscitative efforts. The final decision to stop efforts reversible conditions and can be treated if those conditions can never be as simple as an isolated time interval. Clinical are identified and corrected judgment and respect for human dignity must enter into al rate from cardiac arrest with asystole is decision making. There is little data to guide this decision. dismal. During a resuscitation attempt, brief periods of an Emergency medical response systems should not re rganized complex may appear on the monitor screen, but field personnel to transport every victim of cardiac arrest to a spontaneous circulation rarely emerges. As with PEA, the hospital or emergency department(ED). Transportation with hope for resuscitation is to identify and treat a reversible continuing CPR is justified if interventions are available in cause the ED that cannot be performed in the field, such as Because of the similarity in causes and management of cardiopulmonary bypass or extracorporeal circulation for these two arrest rhythms, their treatment has been combined victims of severe hypothermia( Class IIb) in the second part of the ACLS Pulseless Arrest Algorithm Unless special situations are present(eg, hypothermia), for Patients who have either asystole or PEA will not benefit nontraumatic and blunt traumatic out-of-hospital cardiac from defibrillation attempts. The focus of resuscitation is to arrest, evidence confirms that ACLS care in the ED offers perform high-quality CPR with minimal interruptions and to advantage over ACLS care in the field Stated succinctly, if identify reversible causes or complicating factors. Providers ACLS care in the field cannot resuscitate the victim, ED care

amiodarone is unavailable, lidocaine may be considered. Consider magnesium for torsades de pointes associated with a long QT interval (see below). You should administer the drug during CPR, as soon as possible after rhythm analysis. If a nonshockable rhythm is present and the rhythm is organized (complexes appear regular or narrow), try to palpate a pulse (see Box 12). Rhythm checks should be brief, and pulse checks should generally be performed only if an organized rhythm is observed. If there is any doubt about the presence of a pulse, resume CPR. If the patient has ROSC, begin postresuscitation care. If the patient’s rhythm changes to asystole or PEA, see “Asystole and Pulseless Electrical Activity” below (Boxes 9 and 10). If a perfusing rhythm is transiently restored but not successfully maintained between repeated shocks (recurrent VF/VT), the patient may be a candidate for early treatment with antiarrhythmic medications (see Part 7.3: “Management of Symptomatic Bradycardia and Tachycardia”). During treatment of VF/pulseless VT, healthcare providers must practice efficient coordination between CPR and shock delivery. When VF is present for more than a few minutes, the myocardium is depleted of oxygen and metabolic substrates. A brief period of chest compressions can deliver oxygen and energy substrates, increasing the likelihood that a perfusing rhythm will return after shock delivery.38 Analyses of VF waveform characteristics predictive of shock success have documented that the shorter the time between chest compression and shock delivery, the more likely the shock will be successful.38,39 Reduction in the interval from compression to shock delivery by even a few seconds can increase the probability of shock success.40 Asystole and Pulseless Electrical Activity (Box 9) PEA encompasses a heterogeneous group of pulseless rhythms that includes pseudo-electromechanical dissociation (pseudo-EMD), idioventricular rhythms, ventricular escape rhythms, postdefibrillation idioventricular rhythms, and bradyasystolic rhythms. Research with cardiac ultrasonography and indwelling pressure catheters has confirmed that pulseless patients with electrical activity have associated mechanical contractions, but these contractions are too weak to produce a blood pressure detectable by palpation or noninvasive blood pressure monitoring. PEA is often caused by reversible conditions and can be treated if those conditions are identified and corrected. The survival rate from cardiac arrest with asystole is dismal. During a resuscitation attempt, brief periods of an organized complex may appear on the monitor screen, but spontaneous circulation rarely emerges. As with PEA, the hope for resuscitation is to identify and treat a reversible cause. Because of the similarity in causes and management of these two arrest rhythms, their treatment has been combined in the second part of the ACLS Pulseless Arrest Algorithm. Patients who have either asystole or PEA will not benefit from defibrillation attempts. The focus of resuscitation is to perform high-quality CPR with minimal interruptions and to identify reversible causes or complicating factors. Providers should insert an advanced airway (eg, endotracheal tube, Combitube, LMA). Once the airway is in place, 2 rescuers should no longer deliver cycles of CPR (ie, compressions interrupted by pauses when breaths are delivered). Instead the compressing rescuer should give continuous chest compressions at a rate of 100 per minute without pauses for ventilation. The rescuer delivering ventilation provides 8 to 10 breaths per minute. The 2 rescuers should change compressor and ventilator roles approximately every 2 minutes (when the rhythm is checked) to prevent compressor fatigue and deterioration in quality and rate of chest compressions. When multiple rescuers are present, they should rotate the compressor role about every 2 minutes. Rescuers should minimize interruptions in chest compressions while inserting the airway and should not interrupt CPR while establishing IV or IO access. If the rhythm check confirms asystole or PEA, resume CPR immediately. A vasopressor (epinephrine or vasopressin) may be administered at this time. Epinephrine can be administered approximately every 3 to 5 minutes during cardiac arrest; one dose of vasopressin may be substituted for either the first or second epinephrine dose (Box 10). For a patient in asystole or slow PEA, consider atropine (see below). Do not interrupt CPR to deliver any medication. Give the drug as soon as possible after the rhythm check. After drug delivery and approximately 5 cycles (or about 2 minutes) of CPR, recheck the rhythm (Box 11). If a shockable rhythm is present, deliver a shock (go to Box 4). If no rhythm is present or if there is no change in the appearance of the electrocardiogram, immediately resume CPR (Box 10). If an organized rhythm is present (Box 12), try to palpate a pulse. If no pulse is present (or if there is any doubt about the presence of a pulse), continue CPR (Box 10). If a pulse is present the provider should identify the rhythm and treat appropriately (see Part 7.3: “Management of Symptomatic Bradycardia and Tachycardia”). If the patient appears to have an organized rhythm with a good pulse, begin postresuscitative care. When Should Resuscitative Efforts Stop? The resuscitation team must make a conscientious and competent effort to give patients a trial of CPR and ACLS, provided that the patient has not expressed a decision to forego resuscitative efforts. The final decision to stop efforts can never be as simple as an isolated time interval. Clinical judgment and respect for human dignity must enter into decision making. There is little data to guide this decision. Emergency medical response systems should not require field personnel to transport every victim of cardiac arrest to a hospital or emergency department (ED). Transportation with continuing CPR is justified if interventions are available in the ED that cannot be performed in the field, such as cardiopulmonary bypass or extracorporeal circulation for victims of severe hypothermia (Class IIb). Unless special situations are present (eg, hypothermia), for nontraumatic and blunt traumatic out-of-hospital cardiac arrest, evidence confirms that ACLS care in the ED offers no advantage over ACLS care in the field. Stated succinctly, if ACLS care in the field cannot resuscitate the victim, ED care Part 7.2: Management of Cardiac Arrest IV-61

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