Circulation December 13. 2005 In both the out-of-hospital and in-hospital settings, ATVs increased incidence of sternal fractures in the ACD-CPR re useful for ventilation of adult patients with a pulse who group have an advanced airway (eg, endotracheal tube, esophageal ACD-CPR may be considered for use in the in-hospital tracheal combitube [Combitube], or laryngeal mask airway etting when providers are adequately trained(Class llb). [LMA)in place(Class Ila). For the adult cardiac arrest There is insufficient evidence to recommend for or against patient who does not ha ve an advan the use of ACD-CPR in the prehospital setting(Class ATV may be useful if tidal volumes are delivered by a Indeterminate) flow-controlled, time-cycled ventilator without positive end- Impedance Threshold Device expiratory pressure(PEEP). If the ATV has adjustable output The impedance threshold device(ITD) is a valve that limits control valves, tidal volume should be adjusted to make the chest rise(approximately 6 to 7 mL/kg or 500 to 600 mL), air entry into the lungs during chest recoil between chest with breaths delivered over I second. Until an advanced compressions. It is designed to reduce intrathoracic pressure airway is in place, an additional rescuer should provide and enhance venous return to the heart in initial studies the cricoid pressure to reduce the risk of gastric inflation. Once ITD was used with a cuffed endotracheal tube during bas an advanced airway is in place, the ventilation rate should be tube ventilation and acd-cPr 42-44 The itd and acd 8 to 10 breaths per minute during CPR device are thought to act synergistically to enhance venous Manually triggered, oxygen-powered, flow-limited resus- return during active decompression. In recent reports the ItD has been used during conven citator. In a study of 104 anesthetized nonarrest patients tional CPR4546 with an endotracheal tube or face mask without an advanced airway in place (ie, no endotracheal tube; patients were ventilated through a mask), patients Studies suggest that when the ItD is used with a face mask, it may create the same negative intratracheal pressure as use ventilated by firefighters with manually triggered, oxygen- of the Itd with an endotracheal tube if rescuers can maintain powered, flow-limited resuscitators had less gastric inflation than those ventilated with a bag-mask device (LOE 5). 26 a tight face mask seal. 43, 45, 46 In 2 randomized studies(LOE 1)4447 of 610 adults in Manually triggered, oxygen-powered, flow-limited resuscita cardiac arrest in the out-of-hospital setting, use of ACD-CPR tors may be considered for the management of patients who plus the ITD was associated with improved ROSC and do not have an advanced airway in place and for whom a 24-hour survival rates when compared with use of standard mask is being used for ventilation during CPR. Rescuers CPR alone. A randomized study of 230 adults documented should avoid using the automatic mode of the oxygen- increased admission to the intensive care unit and 24-hour powered, flow-limited resuscitator because it applies contin- survival(LOE 2)45 when an ITD was used during standard uous PEEP that is likely to impede cardiac output during CPR in patients in cardiac arrest (pulseless electrical activity chest compressions( Class In) only) in the out-of-hospital setting. The addition of the ITD Devices to Support Circulation was associated with improved hemodynamics during stan- dard CPR in I clinical study(LOE 2) Active Compression-Decompression CPR Although increased long-term survival rates have not been to actively lift the anterior chest during decompression. It is can improve nemo o tubule s used by trained personnel as an Active compression-decompression CPR(ACD-CPR)is per- documented, when the ITD formed with a hand-held device equipped with a suction cup adjunct to CPR in int adult cardiac arrest patients, it parameters and rosC(Class lla) thought that decreasing intrathoracic pressure during the of 2onmpression phase enhances venous return to the heart. As Mechanical Piston Device The mechanical piston device depresses the sternum via a and Drug Administration for sale in the United States. compressed gas-powered plunger mounted on a backboard. In Results from the use of acd-cpr have been mixed. in 4 I prospective randomized study and 2 prospective random- randomized studies(LOE 127.2, LOE 229. 30) ACD-CPR ized crossover studies in adults(LOE 2), mechanical improved long-term survival rates when it was used by piston CPR used by medical and paramedical personnel adequately trained providers for patients with cardiac arrest in improved end-tidal CO, and mean arterial pressure in patients the out-of-hospital272 and in- hospital,30 settings. In 5 other in cardiac arrest in both the out-of-hospital and in-hospital randomized studies (LOE 131-: LOE 235),however, ne settings. effects were observed. In 4 clinical Mechanical piston CPR may be considered for patients in studies(LOE 3)0.,36-38 ACD-CPR improved hemodynamics cardiac arrest in circumstances that make manual resuscita- over standard CPR, and in I clinical study(Loe 3)39 did not tion difficult(Class Ib). The device should be programmed Frequent training seems to be a significant factor in achie to deliver standard CPR with adequate compression depth at icac. 28 the rate of 100 compressions per minute with a compression ventilation ratio of 30: 2(until an advanced airway is in place) A meta-analysis of 10 trials involving 4162 patients in the and a compression duration that is 50% of the compression- out-of-hospital setting (LOE 1)o and a meta-analysis of 2 decompression cycle length. The device should allow co trials in the in-hospital setting(826 patients) o failed document any early or late survival benefit of ACD- CPR over plete chest wall recoil conventional CPR. The out-of-hospital meta-analysis found Load-Distributing Band CPR or Vest CPR large but nonsignificant worsening in neurologic outcome The load-distributing band (LDB) is a circumferential chest survivors in the ACD-CPR group, and I small study showed compression device composed of a pneumatically or electri-In both the out-of-hospital and in-hospital settings, ATVs are useful for ventilation of adult patients with a pulse who have an advanced airway (eg, endotracheal tube, esophageal￾tracheal combitube [Combitube], or laryngeal mask airway [LMA]) in place (Class IIa). For the adult cardiac arrest patient who does not have an advanced airway in place, the ATV may be useful if tidal volumes are delivered by a flow-controlled, time-cycled ventilator without positive end￾expiratory pressure (PEEP). If the ATV has adjustable output control valves, tidal volume should be adjusted to make the chest rise (approximately 6 to 7 mL/kg or 500 to 600 mL), with breaths delivered over 1 second. Until an advanced airway is in place, an additional rescuer should provide cricoid pressure to reduce the risk of gastric inflation. Once an advanced airway is in place, the ventilation rate should be 8 to 10 breaths per minute during CPR. Manually triggered, oxygen-powered, flow-limited resus￾citators. In a study of 104 anesthetized nonarrest patients without an advanced airway in place (ie, no endotracheal tube; patients were ventilated through a mask), patients ventilated by firefighters with manually triggered, oxygen￾powered, flow-limited resuscitators had less gastric inflation than those ventilated with a bag-mask device (LOE 5).26 Manually triggered, oxygen-powered, flow-limited resuscita￾tors may be considered for the management of patients who do not have an advanced airway in place and for whom a mask is being used for ventilation during CPR. Rescuers should avoid using the automatic mode of the oxygen￾powered, flow-limited resuscitator because it applies contin￾uous PEEP that is likely to impede cardiac output during chest compressions (Class III). Devices to Support Circulation Active Compression-Decompression CPR Active compression-decompression CPR (ACD-CPR) is per￾formed with a hand-held device equipped with a suction cup to actively lift the anterior chest during decompression. It is thought that decreasing intrathoracic pressure during the decompression phase enhances venous return to the heart. As of 2005 no ACD-CPR devices have been cleared by the Food and Drug Administration for sale in the United States. Results from the use of ACD-CPR have been mixed. In 4 randomized studies (LOE 127,28; LOE 229,30) ACD-CPR improved long-term survival rates when it was used by adequately trained providers for patients with cardiac arrest in the out-of-hospital27,28 and in-hospital29,30 settings. In 5 other randomized studies (LOE 131–34; LOE 235), however, no positive or negative effects were observed. In 4 clinical studies (LOE 3)30,36 –38 ACD-CPR improved hemodynamics over standard CPR, and in 1 clinical study (LOE 3)39 did not. Frequent training seems to be a significant factor in achieving efficacy.28 A meta-analysis of 10 trials involving 4162 patients in the out-of-hospital setting (LOE 1)40 and a meta-analysis of 2 trials in the in-hospital setting (826 patients)40 failed to document any early or late survival benefit of ACD-CPR over conventional CPR. The out-of-hospital meta-analysis found a large but nonsignificant worsening in neurologic outcome in survivors in the ACD-CPR group, and 1 small study41 showed increased incidence of sternal fractures in the ACD-CPR group. ACD-CPR may be considered for use in the in-hospital setting when providers are adequately trained (Class IIb). There is insufficient evidence to recommend for or against the use of ACD-CPR in the prehospital setting (Class Indeterminate). Impedance Threshold Device The impedance threshold device (ITD) is a valve that limits air entry into the lungs during chest recoil between chest compressions. It is designed to reduce intrathoracic pressure and enhance venous return to the heart. In initial studies the ITD was used with a cuffed endotracheal tube during bag￾tube ventilation and ACD-CPR.42– 44 The ITD and ACD device are thought to act synergistically to enhance venous return during active decompression. In recent reports the ITD has been used during conven￾tional CPR45,46 with an endotracheal tube or face mask. Studies suggest that when the ITD is used with a face mask, it may create the same negative intratracheal pressure as use of the ITD with an endotracheal tube if rescuers can maintain a tight face mask seal.43,45,46 In 2 randomized studies (LOE 1)44,47 of 610 adults in cardiac arrest in the out-of-hospital setting, use of ACD-CPR plus the ITD was associated with improved ROSC and 24-hour survival rates when compared with use of standard CPR alone. A randomized study of 230 adults documented increased admission to the intensive care unit and 24-hour survival (LOE 2)45 when an ITD was used during standard CPR in patients in cardiac arrest (pulseless electrical activity only) in the out-of-hospital setting. The addition of the ITD was associated with improved hemodynamics during stan￾dard CPR in 1 clinical study (LOE 2).46 Although increased long-term survival rates have not been documented, when the ITD is used by trained personnel as an adjunct to CPR in intubated adult cardiac arrest patients, it can improve hemodynamic parameters and ROSC (Class IIa). Mechanical Piston Device The mechanical piston device depresses the sternum via a compressed gas-powered plunger mounted on a backboard. In 1 prospective randomized study and 2 prospective random￾ized crossover studies in adults (LOE 2),48 –50 mechanical piston CPR used by medical and paramedical personnel improved end-tidal CO2 and mean arterial pressure in patients in cardiac arrest in both the out-of-hospital and in-hospital settings. Mechanical piston CPR may be considered for patients in cardiac arrest in circumstances that make manual resuscita￾tion difficult (Class IIb). The device should be programmed to deliver standard CPR with adequate compression depth at the rate of 100 compressions per minute with a compression￾ventilation ratio of 30:2 (until an advanced airway is in place) and a compression duration that is 50% of the compression￾decompression cycle length. The device should allow com￾plete chest wall recoil. Load-Distributing Band CPR or Vest CPR The load-distributing band (LDB) is a circumferential chest compression device composed of a pneumatically or electri￾IV-48 Circulation December 13, 2005