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). Ifversus shock first, see Part 5: “Electrical Therapies: Auto￾mated 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 informa￾tion 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 imme￾diately 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 compres￾sions 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 qual￾ity 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 compli￾cating 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 se￾quence differs from the one recommended in 200035: it is designed to minimize interruptions in chest compressions. The 2000 recommendations resulted in too many interrup￾tions in chest compressions. In these 2005 recommendations, during treatment of car￾diac 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 adminis￾tering an antiarrhythmic such as amiodarone (Box 8). If IV-60 Circulation December 13, 2005