Mechanical CPR Helps Save Cardiac Patient

Whatcom County (Wash.) Medic One EMTs respond to a 9-1-1 call from a local motel at 2:43 a.m. and find a 63-year-old woman in distress, short of breath and suffering from chest pain and dizziness. While the EMS providers record vital signs and start supplying oxygen, the patient slumps over in bed. She begins to seize and lapse into cardiac arrest just as the paramedic team arrives.

Prehospital Treatment
The patient is moved to the floor. CPR is started, and she is hooked up to the cardiac monitor, which indicates she’s in ventricular fibrillation (v fib). Medics deliver a shock, followed by additional CPR.

The team identifies hypoxia related to her cardiac rhythm as the likely cause of the seizure, using the MADHEADS mnemonic (meningitis, alcohol, diabetes, hypoxia/hyperthermia/head trauma/hydrogen ion, epilepsy/eclampsia, arrhythmia, drugs and/or stroke).

Epinephrine is administered by intraosseous infusion, which has been found to be faster than inserting an IV line in cases like this. CPR is ongoing during these interventions. The paramedics check the patient’s rhythm and administer two additional shocks for v fib.

The team opts to use their portable CPR-assist device, the LUCAS Chest Compression System, to mechanically provide consistent, effective chest compressions. In less than 30 seconds, the device is in place and continuously performing compressions to the 2010 American Heart Association (AHA) specifications, circulating the patient’s blood and helping maintain coronary perfusion pressure. After a few minutes with the mechanical CPR device, the patient shows purposeful movement.

Her clenched jaw interferes with efforts to insert an endotracheal tube (ETT). So the team administers succinylcholine and Versed and inserts the ET tube to protect her airway and monitor her end-tidal CO2 (EtCO2). To improve blood return to the heart, a ResQPOD impedance threshold device was connected to her bag-valve mask and then ETT.

The team is able to get a sustainable pulse back thanks to the cascade of interventions–including airway management; consistent, high-quality, mechanized CPR; and administration of the anti-dysrhythmic drug amiodarone hydrochloride. They transport the patient to PeaceHealth St. Joseph Medical Center, the local Level 1 percutaneous coronary intervention (PCI) capable hospital.

Although the crews switched off the mechanical compressions after return of spontaneous circulation (ROSC), they kept the LUCAS in place as the patient was put onto the stretcher, moved into the narrow hallway, carried down a set of stairs, loaded into the ambulance, driven to the hospital and transferred to the emergency department (ED).

Patient Outcome
Medics started transport at 3:16 a.m.–33 minutes after the BLS crew’s initial arrival on scene. Patient movement time from the motel to the medic unit accounted for approximately 10 of these minutes. Then, just as the medic unit arrived at the hospital, the patient lost blood pressure and experienced pulseless electrical activity.

The crew reactivated the LUCAS device to resume high-quality compressions and mechanically free the team to focus on other cardiac care. The use of a device like this also negates the need for the crew to stand and perform CPR while moving from the ambulance into the emergency department (ED) and during the patient transfer to the hospital.

The patient again regains ROSC, and therapeutic hypothermia is started inside the ED. She’s triaged to the cardiac catheterization lab. With the CPR-assist device still in place, cardiologists clear a blockage in her left anterior descending coronary artery and insert a stent.

Although therapeutic hypothermia is standard policy for such patients, this patient begins to wake before she’s fully cooled. So hypothermia is discontinued, and the patient is extubated after 24 hours. Cardiologists stent her right coronary artery, and she’s subsequently discharged. She has a complete neurologic recovery despite 15 minutes of out-of-hospital cardiac arrest. In less than a month, she’s back home living a normal life.

Teaching Points
Many EMS agencies are experiencing what this Washington state crew experienced. Consistent, effective chest compressions are critical to increasing patient survival rates and avoiding neurological damage.

High-quality chest compressions have been increasingly emphasized in the 2010 AHA Guidelines for CPR & ECC. This includes compressions delivered at the defined rate (at least 100/minute) at adequate depth (2 inches/5 cm for adults) and have complete chest recoil after each compression, minimized interruptions in compressions and avoidance of excessive ventilation.

Effective compressions circulate blood and oxygenate the brain and other vital organs, thus reducing the risk for permanent neurological damage. Chest compressions increase coronary artery perfusion pressure, keeping the heart muscle from suffering ischemia. Consistent, forceful compressions prevent the pooling of blood in the heart, helping to prepare it for delivery of a defibrillating shock. Any lapse in chest compressions causes perfusion pressure to drop dramatically, stopping the flow of blood. In those brief interruptions, providers may lose any ground they’ve gained.

As most responders know, it’s extremely difficult to provide textbook CPR in real life. EMTs and paramedics perform manual CPR based on their size, physical capabilities and often their surge of adrenaline. For example, people who are physically smaller may have less ability to perform deep compressions, and people who are physically larger may over compress. In either case, as the person performing CPR grows fatigued, the effectiveness of CPR suffers. Thus, chest compressions are commonly done ineffectively despite good training and the best intentions.

Mechanical chest compression devices eliminate those issues. Mechanical CPR devices never need a break. They do effective compressions designed to meet the AHA standards. They help patients maintain good circulation despite significant ongoing cardiac events. This allows providers the time and opportunity to apply other therapies, make clinical decisions and safely get to the hospital while performing CPR.

When it comes to patient survival, many factors contribute to high go-home survival rates. Whatcom Medic One has a comprehensive process for responding to cardiac arrests: CPR, airway management, dysrhythmia management, therapeutic hypothermia, mechanical CPR and EtCO2 monitoring. Patient care is improved if these tasks can be performed consistently and effectively. Mechanical CPR significantly contributes to improved patient care.

Any system considering new technology has to balance costs compared with improved patient care and safety for its providers. All devices have advantages and disadvantages.

This case illustrates how Whatcom Medic One is overcoming some challenges EMS faces in delivering optimal CPR, which is essential to patient survival. These challenges include tight quarters; competing demands for paramedic attention to assess patients and provide other interventions; interruptions in hands-only CPR for defibrillation; tight choreography, as rescuers swap places to alternate ventilation and compression; performing CPR during transport while protecting rescuer safety; and the difficulty of delivering forceful chest compressions timed to AHA standards over a sustained period.

The bottom line in moving ahead with LUCAS is that it provides better patient care and an opportunity for EMS providers to provide a high standard of patient care, and hopefully, better patient outcomes. JEMS

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This article originally appeared in November 2011 JEMS as “Mechanical Matters: Consistent chest compressions help save patient.”

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