Some of the most important developments center around providing real-time feedback to responders performing CPR. For example, Zoll has embedded accelerometers in electrodes that measure the depth of each compression and coach responders to push harder and faster, if necessary. That’s in keeping with revised American Heart Association standards1 from 2010 that emphasize the importance of chest compressions, reordering the CPR mnemonic from A-B-C (airway breathing compression) to C-B-A (compression breathing airway.) In its 2015 revision,2 AHA continued to emphasize high quality CPR and specifically advised minimizing interruptions to chest compressions. Industry advances, like electrocardiograms that a responder can read and assess while working on a patient, have helped implement this goal. Zoll’s See-Through CPR filters out noise and compression artifacts, displaying the underlying rhythm generated by the patient. A clear waveform can help clinicians deliver shocks at the right time.
Technology has advanced to help responders measure not just pulse but also ventilation. Capnography, initially used to monitor patients under anesthesia, is becoming common in emergency medicine and is a feature of most defibrillators and monitors like PhysioControl’s LifePak 20e Debrillator/Monitor with CodeManagement Module. Capnographs measure end tidal carbon dioxide by analyzing the patient’s exhalation with infrared absorption spectroscopy. The results are read on a monitor (capnogram) or by a color change on a strip of material attached to a patient’s breathing device (calorimetric capnography). Mainstream capnography is built into ventilation units for intubated patients, but sidestream capnography siphons off a sample of gas and can be used in patients fitted with a face mask or nasal cannula. If a patient is not respiring or if the intubation tube is in the esophagus rather than the trachea, then the machine will not capture or report carbon dioxide gas. Capnography adds to the clinician’s toolkit for measuring ventilation, which at one time was limited to auscultation and blood gas analysis.3
With the advent of noninvasive near infrared spectroscopy (NIRS), providers can also easily monitor bloodflow in other parts of the body including the brain. NIR beams can penetrate bone,4 making them useful sensors to measure regional oxygenation subcutaneously in parts of the body like the brain. Like capnography, NIRS is also moving from surgical settings to emergency settings as the technology involved advances.
Then there are automatic chest compression systems, which bypass human performers altogether. Patients are placed on a back brace and compressions are deployed automatically by a plunger or band on the chest. The machines allow first responders5 to move patients experiencing out-of-hospital cardiac arrest down flights of stairs without stopping compressions and to continue compressions for long periods of time without fatigue (known to hinder6 quality of CPR performance.) A trial7 of Physio-Control’s Lucas chest compression system, funded in part by the manufacturer, found that patient outcomes were similar whether manual CPR or the machine was used.
Options Improve for Both Amateurs and Experts
As Automatic External Defibrillators (AEDs) have become easier and more commonplace, lay responders are stepping in to keep patients alive in time for emergency personal to connect them to advanced life support. AEDs8 have been simplified, lightened, and equipped with voice commands. That’s good for the general public who come across a person in sudden cardiac arrest (an event that strikes over 300,000 Americans a year.) But it’s also good for trained professionals like hospital staff, said Vinay Nadkarni, MD, medical and research director of the Center for Simulation, Advanced Education and Innovation at The Children’s Hospital of Philadelphia.
“It turns out that the frequency with which healthcare providers taking care of patients on the general ward—not in the ICU and not in the emergency departments, but in the general ward and the clinics—they rarely encountered a cardiac arrest and so they were scared to death of the defibrillators,” he told RT. “So it turns out that if you place these automatic external defibrillators instead of the big fancy monitor defibrillators in these locations, like in clinics, on wards, in hospitals…where people didn’t frequently use the monitor/defibrillators, again you can get a very effective response and better survival through technology.”
Then there are wards where highly trained professionals who resuscitate patients frequently use some of the most cutting-edge technology out there: like extracorporeal membrane oxygenation (ECMO), an artificial heart and lung machine that operates outside the patient’s body.
“That’s a really high tech solution right now and it’s not for everybody, but with highly trained teams and highly trained centers, a lot of cardiac surgery, it’s becoming more and more practical and the survival rates when it’s applied to the right patients is now more than 50%. It used to be 5%,” he said.
On the Horizon
Nadkarni is excited about a couple cutting-edge therapies that go beyond CPR to resuscitate patients.
One is called whole body periodic acceleration. Taking a cue from the ventilatory response of patting an infant on the bottom, researchers are investigating the therapeutic effects of passive exercise on heart health. In pigs, this approach—which rocks the patient back and forth at a specific frequency—helped preserve heart rate variability after eight minutes of ventricular fibrillation.9
What else does Nadkarni look forward to? “Magnets,” he said. Nadkarni thinks the next major innovation in resuscitation will come from finding ways to move blood around the body without the heart, a heart substitute, or even chest compressions.
“Think about magnets. There’s iron in the bloodstream right? Little red blood cells have iron in their nucleus, in the middle of them. So maybe there’s a way that we could move them, attract them by aligning magnets in a certain way that it gets these tiny little iron nanoparticles to align and to move toward that magnet,” he said. On a smaller scale, he said, much of what emergency technicians need comes down to adopting technology from other departments but making it smaller, faster, and more rugged. “Quick, easy, and easy to interpret is really what’s needed. We have pretty much in our own head the most effective tools.” RT
Rose Rimler is associate editor of RT. For further information, contact [email protected]