Certain devices have been developed to increase the effectiveness of CPR:

• Automatic transport ventilators
• Manually initiated, oxygen-sourced flow-limiting resuscitators
• Circulatory devices supporting CPR 
• Mechanical assist devices for cardiogenic shock

Automatic Transport Ventilators

These devices are powered pneumatically and provide time and pressure-cycled respirations during transport in EMS vehicles. This type of device is beneficial as it allows EMS providers to complete other necessary tasks. Oxygen and power are required for their use, and consequently, providers must always carry backup devices, such as a bag-mask, available.

Automatic transport ventilator inside an EMS vehicle.⁸

Manually-Initiated, Oxygen-Sourced Flow-Limiting Resuscitators

The use of these devices reduces the amount of gastric distension compared to that generated while using bag-mask devices. When in use, providers must avoid automatic mode as this can elevate positive end-expiratory pressures, leading to decreased venous return and cardiac output during compressions. 

Circulatory Devices Supporting CPR

Some devices are designed specifically to improve chest compressions.

Active Compression-Decompression CPR (ACD-CPR)

ACD-CPR is achieved with a device that uses suction to lift the chest in the middle part of the sternum between compressions. This causes negative intrathoracic pressure, which may increase venous return. The research is unclear as to the benefits of the device. Although there is some evidence for benefit in ROSC, short-term survival, and neurologic recovery, other data show no difference in these outcomes. 

Phasing Thoracic-Abdominal Compressive-Decompressive CPR

This technique combines ACD-CPR and IAC-CPR by using a hand-held device that performs chest compressions and abdominal recoil, followed by chest recoil and abdominal compression. There is no evidence as of yet for its benefits for OHCAs.

Impedance Threshold Devices (ITD)

This device senses pressure at the entry of an airway device such as an endotracheal tube or face mask. It minimizes air entering the lung during chest recoil, which improves venous return by causing negative intrathoracic pressure. It does not alter positive pressure ventilations or exhalation. Used with ACD-CPR, it can enhance venous return further. Research is unclear as to its benefits, but it may be useful to combine ITD and ACD-CPR in resuscitation efforts with well-trained staff. 

Mechanical Piston Device

This device uses electric power or compressed gas to control a piston that then compresses the sternum. It may have a suction cup. While it improves physiological parameters such as MAP and ETCO₂, it has not been proven to improve survival rates. Further, it can cause interruptions in CPR, especially while it is being attached or removed. Consequently, traditional chest compressions remain more effective in routine cases.

Related Video: One Quick Question: What is a LUCAS Device?

Load-Distributing Band (Vest) CPR

This device wraps around the chest and uses electric power or compressed gas to provide chest compressions. Studies showed that, while it improved hemodynamic parameters, ROSC, and hospital discharge survival rates, it worsened the odds of survival at 30 days. Consequently, the device may cause harm, and its use should only be considered with highly trained providers in very controlled situations. 

Extracorporeal and Invasive Perfusion Techniques

Extracorporeal membrane oxygenation (ECMO) and cardiopulmonary bypass can be combined to treat cardiac arrest. These are highly specialized techniques requiring considerable medical skills and resources. Studies reveal that these therapies can increase survival rates for OHCA and IHCA patients under 75 years with potentially reversible conditions. While it is not recommended for routine care, it may be beneficial when available and used in patients who qualify, such as those requiring transplantation or revascularization.

The ECMO machine acts as the heart and lungs.

Related Video: ECMO Explained

Intra-Aortic Balloon Pump (IABP)

This mechanic assist device is used for cardiogenic shock and increases cardiac and systemic circulation while improving cardiac output. Inflation and deflation of an intra-aortic catheter are timed with the phases of the cardiac cycle to increase blood pressure and coronary and brain perfusion as well as reduce cardiac afterload. It increases cardiac output between 10 and 20% while slowing the heart rate and increasing perfusion. 

The device is primarily used in conjunction with cardiac surgeries during which the patient has cardiogenic shock. It is contraindicated for patients with certain aortic valvular dysfunctions and irreversible cardiac disease. The 2013 AHA STEMI guidelines suggest it is of benefit in cardiogenic shock patients after STEMIs that do not respond to pharmaceutical therapy.  

Ventricular Assist Devices

These devices are used to mechanically assist the heart pump function temporarily following cardiac surgery or damage after a heart attack. It can be combined with ECMO to improve oxygenation. These devices can be implanted and even permanent for patients awaiting transplants or those who do not qualify for transplantation.