As the nurse checked in on the elderly female patient awaiting a consultation in the Houma, La., office of oral and maxillofacial surgeon Christopher Saal, MD, DDS, she saw the patient slumped over in the chair.
"Sleeping on me in there?" asked the nurse.
When the patient didn't respond, the nurse investigated and found a woman in cardiac arrest, specifically ventricular fibrillation. Even by emergency-response standards, the situation was dire. "Not that there's ever a good day for a patient emergency, but ours happened minutes after a power outage," recalls Dr. Saal. While assistants called for emergency crews on cell phones, Dr. Saal laid the patient on the floor and began mouth-to-mouth resuscitation. A nurse retrieved an automated external defibrillator (AED) and attached the leads to the patient. Dr. Saal administered two shocks. The second restored the patient's heartbeat. Paramedics arrived and transferred the patient to the hospital.
Equipment you never want to use
Defibrillators, of course, are a necessary capital equipment expense in every surgical setting. Even facilities that primarily do conscious sedation procedures or minimally invasive surgery with healthy patients are required to have emergency equipment available for their patients.
The ASA's Guidelines for Sedation and Analgesia by Non-Anesthesiologists say that a defibrillator should be available immediately for all patients during deep sedation procedures. During moderate sedation, a defibrillator should be available immediately even for patients with mild cardiovascular disease (hypertension, for example) as well as those with more severe conditions, such as ischemia or congestive failure.
You should "approach buying and maintaining the defibrillator the same as any other piece of equipment, taking into account clinical efficacy, user-friendliness, features and cost-efficiency for your practice's needs," says Dr. Saal. The one big difference, adds Harold Finkel, MD, a pediatric neurologist at the Michigan Institute for Neurological Disorders, is that "you hope you'll never actually have to use your defibrillator."
AED, manual or both?
Increasingly, outpatient surgical facilities find themselves deciding between AEDs, manual biphasic defibrillators or combinations thereof. Many manufacturers, such as Philips, offer both types as well as hybrid devices that are either AEDs with certain manual features or manual defibrillators with AED modes. Zoll, for instance, offers both an AED (the AED ) and M-Series, a combination manual and automated defibrillator, monitor and pacing device.
From a pure pricing standpoint, AEDs are the clear favorite over manual defibrillators, listing anywhere from about $1,500 for a no-frills automated shock box to about $4,000 for models designed to provide more substantial clinical information and allow greater user control of the waveform and energy delivered.
Manual defibrillators - most of which include an AED mode - typically have ECG monitoring capabilities and are designed for personnel comfortable with ACLS-level patient rescue. They list anywhere from about $7,500 to $30,000. The less expensive models incorporate ECG monitoring and display. The higher-end models incorporate many monitoring functions, including pulse oximetry, end-tidal CO2, invasive and non-invasive blood pressure, ECG and manual and automated defibrillation capabilities.
Mayo clinic anesthesiologist John Abenstein, MD, says AEDs are a strong option in settings manned primarily by staff with BLS training but "do not necessarily produce a better diagnosis" than an advanced practitioner controlling a manual model. The trained clinician, he says, can recognize and treat types of arrhythmia other than ventricular fibrillation or asystole.
Ultimately, it comes down to the types of procedures a facility does and clinician preference, emergency-response experience and comfort. Dr. Finkel would prefer to hold to the "first do no harm" dictum and use an AED designed to help deliver the patient to more experienced rescuers. Dr. Saal prefers a higher-end AED that "takes away some of the decision-making pressure" but still lets him at least control the energy of the shock. He replaced a device at his facility that only let him administer a shock when and how the machine decided to deliver energy. Jay Klarsfeld, MD, an ENT surgeon and the president of Advanced Specialty Care in Danbury, Conn., still maintains a manual device in his center because "our anesthesiologist prefers it, and it feels more comfortable" taking full control in case of rescuing a patient in cardiac arrest.
Evaluating energy delivery
The waveform or clinical delivery of energy is one way defibrillator manufacturers differentiate themselves. Some point to studies showing the superiority of their waveform over competitors. "We now have a rather confused marketplace because energy protocols differ widely now, unlike in the past," says Jim Casella of Philips Medical. Not long ago, all devices delivered 200 Joules at the first shock, 300J on the second and 360J on the third.
When evaluating a device's energy delivery, keep several factors in mind, says David Barash, MD, the vice president and medical director of Access Cardio Solutions. These include elapsed time to first shock, impedance compensation performance (does the shock compensate for chest resistance?) and progressive energy on repeat shocks that limit the peak current. Buyers and manufacturers we talked to pointed to several other major decision-making factors.
- Early response. This entails not only the time elapsed to analyze the patient and deliver the first shock, but also the ease of attaching the electrodes (which replace paddles in AEDs), convenience of storage (such as wall-mounting or portable, so you can place it on a crash cart), weight and portability and ease of use. For example, how many buttons does the device have? How easy is it to read the displays?
- Ease of routine maintenance. Most devices perform an automatic self-test, eliminating the need for daily tests before the first case. Companies can help troubleshoot the devices, but the user's still responsible for battery upkeep and replacing the electrodes. Some devices offer a rechargeable battery. Another includes a tag that informs staff of the due date for changing the pad.
- Customizability. Some facilities want more extensive memory cards to be able to review the event. Some want to upgrade the device software piece by piece, adding monitoring functions as they go along. Still others merely want the physician to be able to re-program the AED waveform or alarm functions.