Enhanced CPR May Improve Survival to Discharge

It may be time to reevaluate the use of standard cardiopulmonary resuscitation for out-of-hospital cardiac arrest, now that results from a large prospective, randomized trial show better outcomes with a more advanced form of CPR.

Treatment with active compression-decompression CPR with enhanced negative intrathoracic pressure during the decompression phase significantly increased survival to hospital discharge with favorable neurologic function, compared with standard CPR, after an out-of-hospital cardiac arrest of presumed cardiac cause. The findings come from a study of 1,653 patients treated for cardiac arrest by emergency medical service professionals in seven geographic regions; patients were randomized to receive standard or enhanced CPR (Lancet 2011;377:301-11).

Treatment with the enhanced CPR method led to a 53% relative increase in survival to hospital discharge with a modified Rankin Scale score of no more than 3 – the study’s primary end point – compared with standard CPR. Consistent survival differences between study groups were noted throughout the study, independent of age, study site, sex, and date of treatment.

In addition, overall survival increased by nearly 50% at 1 year in the intervention group, compared with those who received standard CPR. Neurologic function was similar between the two groups at 90 days and 365 days after the out-of-hospital cardiac arrest, reported Dr. Tom P. Aufderheide, professor of emergency medicine at the Medical College of Wisconsin in Milwaukee, and his coinvestigators.

The study was sponsored by Advanced Circulatory Systems, which makes two of the devices used in the intervention arm of the study. The company helped investigators to obtain government funding, design the study, interpret the data, and write the report for publication.

Improvements in out-of-hospital CPR are needed given the poor overall survival rates, which average about 5% in North America and Europe. "Poor survival rates persist, in part, because manual chest compression and ventilation ... is inherently inefficient, providing less than 25% of healthy blood flow to the heart and brain," they wrote.

Research has shown that decreased intrathoracic pressure is associated with a simultaneous decrease in intracranial pressure and increased blood flow to the heart and brain. Clinical studies have also shown substantial improvement in 24-hour survival with the use of increased negative intrathoracic pressure during the decompression phase of CPR. Active compression-decompression CPR increases ventilation to 13.5 L/min, compared with 7.8 L/min with standard CPR, the researchers noted.

Adults with out-of-hospital cardiac arrest were eligible for the study. Patients were initially excluded for obvious or likely traumatic injuries causing cardiac arrest, a preexisting do-not-resuscitate order, signs of obvious clinical death, conditions that precluded the use of CPR, an in-hospital cardiac arrest, or recent sternotomy. The final exclusion criteria included all initial criteria plus receiving less than 1 minute of CPR by EMS personnel and a complete airway obstruction; intubation with a leaky or uncuffed advanced airway device; noncardiac cause of arrest; and presence of a stoma, tracheotomy, or tracheostomy.

Rescuers performed active compression-decompression CPR with a handheld CPR device (ResQPump/CardioPump) that consists of a suction cup attached to the chest, a handle, an audible metronome set to 80 beats per minute, and a force gauge to guide compression depth and chest wall recoil. This technique requires compression to the same depth as standard CPR and then upward lifting to fully decompress the chest. In addition, an impedance-threshold device (ResQPOD), with an inspiratory resistance of 16 cm H2O and less than 5 cm H2O expiratory impedance, was connected to a face mask or advanced airway.

The first EMS provider to arrive at the site started chest compressions as soon as possible for patients in both study groups. Standard CPR, defibrillation, and advanced life support treatment were performed in accordance with local policy and the American Heart Association guidelines. A compression-to-ventilation ratio of 30:2 was used during basic life support for both techniques; however, for the intervention protocol, rescuers provided CPR at 80 compressions per minute as soon as possible. The active compression-decompression device force gauge was used to help achieve the recommended compression depth and complete chest recoil.

The seven study sites had 46 EMS agencies in urban, suburban, and rural areas, and served 2.3 million people. In all, 4,940 EMS personnel underwent didactic and hands-on training before the study started and every 6 months thereafter.

Nearly all survivors had no or mild long-term neurologic deficits, which did not differ between groups. Disabilities rating scale scores, which are a key functional assessment of patients with severe disability, did not differ between groups.

"We suggest that improved cerebral perfusion during CPR in the intervention group resulted in reduced cerebral ischemia but that recovery and restoration of brain function might take more time than does the recovery of cardiac function," the investigators wrote.

"These findings also support the idea that improved perfusion outside the hospital in the intervention group could result in more stable candidates for cardiac catheterization than were found in the standard CPR group, resulting in more patients in the intervention group being provided cardiac catheterization," they added.

While there were no differences in overall major adverse event rates between groups, the "occurrence of pulmonary edema was increased by 50% in the device group, which was coexistent with the increase in survival with favorable neurologic function. The clinical relevance of this finding is unclear: the percentage increase in pulmonary edema (46%) was proportional to the increase in survival in the intervention group (53%)," the researchers observed.

Dr. Aufderheide has been a consultant to Jolife Medical and Medtronic Foundation. One of the listed authors is coinventor of the two devices used in the study and founded Advanced Circulatory Systems. Another author has received lecture fees from Advanced Circulatory Systems, and another has significant financial relationships with Baxter, Vita Care Medical Products, and Cook Medical.

It may be time to reevaluate the use of standard cardiopulmonary resuscitation for out-of-hospital cardiac arrest, now that results from a large prospective, randomized trial show better outcomes with a more advanced form of CPR.

Treatment with active compression-decompression CPR with enhanced negative intrathoracic pressure during the decompression phase significantly increased survival to hospital discharge with favorable neurologic function, compared with standard CPR, after an out-of-hospital cardiac arrest of presumed cardiac cause. The findings come from a study of 1,653 patients treated for cardiac arrest by emergency medical service professionals in seven geographic regions; patients were randomized to receive standard or enhanced CPR (Lancet 2011;377:301-11).

Treatment with the enhanced CPR method led to a 53% relative increase in survival to hospital discharge with a modified Rankin Scale score of no more than 3 – the study’s primary end point – compared with standard CPR. Consistent survival differences between study groups were noted throughout the study, independent of age, study site, sex, and date of treatment.

In addition, overall survival increased by nearly 50% at 1 year in the intervention group, compared with those who received standard CPR. Neurologic function was similar between the two groups at 90 days and 365 days after the out-of-hospital cardiac arrest, reported Dr. Tom P. Aufderheide, professor of emergency medicine at the Medical College of Wisconsin in Milwaukee, and his coinvestigators.

The study was sponsored by Advanced Circulatory Systems, which makes two of the devices used in the intervention arm of the study. The company helped investigators to obtain government funding, design the study, interpret the data, and write the report for publication.

Improvements in out-of-hospital CPR are needed given the poor overall survival rates, which average about 5% in North America and Europe. "Poor survival rates persist, in part, because manual chest compression and ventilation ... is inherently inefficient, providing less than 25% of healthy blood flow to the heart and brain," they wrote.

Research has shown that decreased intrathoracic pressure is associated with a simultaneous decrease in intracranial pressure and increased blood flow to the heart and brain. Clinical studies have also shown substantial improvement in 24-hour survival with the use of increased negative intrathoracic pressure during the decompression phase of CPR. Active compression-decompression CPR increases ventilation to 13.5 L/min, compared with 7.8 L/min with standard CPR, the researchers noted.

Adults with out-of-hospital cardiac arrest were eligible for the study. Patients were initially excluded for obvious or likely traumatic injuries causing cardiac arrest, a preexisting do-not-resuscitate order, signs of obvious clinical death, conditions that precluded the use of CPR, an in-hospital cardiac arrest, or recent sternotomy. The final exclusion criteria included all initial criteria plus receiving less than 1 minute of CPR by EMS personnel and a complete airway obstruction; intubation with a leaky or uncuffed advanced airway device; noncardiac cause of arrest; and presence of a stoma, tracheotomy, or tracheostomy.

Rescuers performed active compression-decompression CPR with a handheld CPR device (ResQPump/CardioPump) that consists of a suction cup attached to the chest, a handle, an audible metronome set to 80 beats per minute, and a force gauge to guide compression depth and chest wall recoil. This technique requires compression to the same depth as standard CPR and then upward lifting to fully decompress the chest. In addition, an impedance-threshold device (ResQPOD), with an inspiratory resistance of 16 cm H2O and less than 5 cm H2O expiratory impedance, was connected to a face mask or advanced airway.

The first EMS provider to arrive at the site started chest compressions as soon as possible for patients in both study groups. Standard CPR, defibrillation, and advanced life support treatment were performed in accordance with local policy and the American Heart Association guidelines. A compression-to-ventilation ratio of 30:2 was used during basic life support for both techniques; however, for the intervention protocol, rescuers provided CPR at 80 compressions per minute as soon as possible. The active compression-decompression device force gauge was used to help achieve the recommended compression depth and complete chest recoil.

The seven study sites had 46 EMS agencies in urban, suburban, and rural areas, and served 2.3 million people. In all, 4,940 EMS personnel underwent didactic and hands-on training before the study started and every 6 months thereafter.

Nearly all survivors had no or mild long-term neurologic deficits, which did not differ between groups. Disabilities rating scale scores, which are a key functional assessment of patients with severe disability, did not differ between groups.

"We suggest that improved cerebral perfusion during CPR in the intervention group resulted in reduced cerebral ischemia but that recovery and restoration of brain function might take more time than does the recovery of cardiac function," the investigators wrote.

"These findings also support the idea that improved perfusion outside the hospital in the intervention group could result in more stable candidates for cardiac catheterization than were found in the standard CPR group, resulting in more patients in the intervention group being provided cardiac catheterization," they added.

While there were no differences in overall major adverse event rates between groups, the "occurrence of pulmonary edema was increased by 50% in the device group, which was coexistent with the increase in survival with favorable neurologic function. The clinical relevance of this finding is unclear: the percentage increase in pulmonary edema (46%) was proportional to the increase in survival in the intervention group (53%)," the researchers observed.

Dr. Aufderheide has been a consultant to Jolife Medical and Medtronic Foundation. One of the listed authors is coinventor of the two devices used in the study and founded Advanced Circulatory Systems. Another author has received lecture fees from Advanced Circulatory Systems, and another has significant financial relationships with Baxter, Vita Care Medical Products, and Cook Medical.

It may be time to reevaluate the use of standard cardiopulmonary resuscitation for out-of-hospital cardiac arrest, now that results from a large prospective, randomized trial show better outcomes with a more advanced form of CPR.

Treatment with active compression-decompression CPR with enhanced negative intrathoracic pressure during the decompression phase significantly increased survival to hospital discharge with favorable neurologic function, compared with standard CPR, after an out-of-hospital cardiac arrest of presumed cardiac cause. The findings come from a study of 1,653 patients treated for cardiac arrest by emergency medical service professionals in seven geographic regions; patients were randomized to receive standard or enhanced CPR (Lancet 2011;377:301-11).

Treatment with the enhanced CPR method led to a 53% relative increase in survival to hospital discharge with a modified Rankin Scale score of no more than 3 – the study’s primary end point – compared with standard CPR. Consistent survival differences between study groups were noted throughout the study, independent of age, study site, sex, and date of treatment.

In addition, overall survival increased by nearly 50% at 1 year in the intervention group, compared with those who received standard CPR. Neurologic function was similar between the two groups at 90 days and 365 days after the out-of-hospital cardiac arrest, reported Dr. Tom P. Aufderheide, professor of emergency medicine at the Medical College of Wisconsin in Milwaukee, and his coinvestigators.

The study was sponsored by Advanced Circulatory Systems, which makes two of the devices used in the intervention arm of the study. The company helped investigators to obtain government funding, design the study, interpret the data, and write the report for publication.

Improvements in out-of-hospital CPR are needed given the poor overall survival rates, which average about 5% in North America and Europe. "Poor survival rates persist, in part, because manual chest compression and ventilation ... is inherently inefficient, providing less than 25% of healthy blood flow to the heart and brain," they wrote.

Research has shown that decreased intrathoracic pressure is associated with a simultaneous decrease in intracranial pressure and increased blood flow to the heart and brain. Clinical studies have also shown substantial improvement in 24-hour survival with the use of increased negative intrathoracic pressure during the decompression phase of CPR. Active compression-decompression CPR increases ventilation to 13.5 L/min, compared with 7.8 L/min with standard CPR, the researchers noted.

Adults with out-of-hospital cardiac arrest were eligible for the study. Patients were initially excluded for obvious or likely traumatic injuries causing cardiac arrest, a preexisting do-not-resuscitate order, signs of obvious clinical death, conditions that precluded the use of CPR, an in-hospital cardiac arrest, or recent sternotomy. The final exclusion criteria included all initial criteria plus receiving less than 1 minute of CPR by EMS personnel and a complete airway obstruction; intubation with a leaky or uncuffed advanced airway device; noncardiac cause of arrest; and presence of a stoma, tracheotomy, or tracheostomy.

Rescuers performed active compression-decompression CPR with a handheld CPR device (ResQPump/CardioPump) that consists of a suction cup attached to the chest, a handle, an audible metronome set to 80 beats per minute, and a force gauge to guide compression depth and chest wall recoil. This technique requires compression to the same depth as standard CPR and then upward lifting to fully decompress the chest. In addition, an impedance-threshold device (ResQPOD), with an inspiratory resistance of 16 cm H2O and less than 5 cm H2O expiratory impedance, was connected to a face mask or advanced airway.

The first EMS provider to arrive at the site started chest compressions as soon as possible for patients in both study groups. Standard CPR, defibrillation, and advanced life support treatment were performed in accordance with local policy and the American Heart Association guidelines. A compression-to-ventilation ratio of 30:2 was used during basic life support for both techniques; however, for the intervention protocol, rescuers provided CPR at 80 compressions per minute as soon as possible. The active compression-decompression device force gauge was used to help achieve the recommended compression depth and complete chest recoil.

The seven study sites had 46 EMS agencies in urban, suburban, and rural areas, and served 2.3 million people. In all, 4,940 EMS personnel underwent didactic and hands-on training before the study started and every 6 months thereafter.

Nearly all survivors had no or mild long-term neurologic deficits, which did not differ between groups. Disabilities rating scale scores, which are a key functional assessment of patients with severe disability, did not differ between groups.

"We suggest that improved cerebral perfusion during CPR in the intervention group resulted in reduced cerebral ischemia but that recovery and restoration of brain function might take more time than does the recovery of cardiac function," the investigators wrote.

"These findings also support the idea that improved perfusion outside the hospital in the intervention group could result in more stable candidates for cardiac catheterization than were found in the standard CPR group, resulting in more patients in the intervention group being provided cardiac catheterization," they added.

While there were no differences in overall major adverse event rates between groups, the "occurrence of pulmonary edema was increased by 50% in the device group, which was coexistent with the increase in survival with favorable neurologic function. The clinical relevance of this finding is unclear: the percentage increase in pulmonary edema (46%) was proportional to the increase in survival in the intervention group (53%)," the researchers observed.

Dr. Aufderheide has been a consultant to Jolife Medical and Medtronic Foundation. One of the listed authors is coinventor of the two devices used in the study and founded Advanced Circulatory Systems. Another author has received lecture fees from Advanced Circulatory Systems, and another has significant financial relationships with Baxter, Vita Care Medical Products, and Cook Medical.