Consider New Mnemonic for the Crashing Patient
By Elizabeth Mechcatie
Elsevier Global Medical News
BOSTON -- A greater emphasis on compressions and defibrillation--and less emphasis on the airway and breathing--are among the important concepts to consider when a medically crashing patient arrives in the emergency department.
This was the message in a presentation last month at the Scientific Assembly of the American College of Emergency Physicians.
Only three approaches have been shown to be effective in reviving the crashing patient in the post-arrest period: good compressions, rapid defibrillation, and therapeutic hypothermia, explained Dr. Amal Mattu, program director of the emergency medicine residency, University of Maryland, Baltimore. By effective, he means survival to hospital discharge with good neurologic recovery.
During his presentation, "The Crashing Patient: Clinical Pearls for Pre- or Post-Cardiac Arrest," Dr. Mattu, who is also associate professor in the department of emergency medicine at the university, presented a mnemonic to supplement the longstanding emergency medicine "A-B-C" mantra for "Airway, Breathing, and Compressions." He illustrated his points using an A-B-C-D-E-F mnemonic, representing the following key considerations in the crashing patient:
Aortic Disasters: A thoracic aortic dissection (TAD) and a ruptured abdominal aortic aneurysm (AAA) should be considered in the medically crashing patient, whether or not "classic" symptoms are present. Studies in the literature "demonstrate the traditional early teaching we all received about how these disastrous presentations present is not completely accurate," Dr. Mattu said in an interview, noting that many patients with one of these two conditions present without the classic chest, abdominal or back pain. "Always think about the aorta, even if the patient has no complaint of abdominal or back pain." He also referred to a study of people who had died of an AAA or TAD, in which the researchers identified pulseless electrical activity (PEA) as the most common presenting cardiac rhythm in those patients.
Acidosis: In the crashing patient, metabolic acidosis should always be considered a possibility, Dr. Mattu advised. That is particularly important for the patient who appears very sick, needs to be intubated, and who should not be put on a ventilator set at the "usual" respiratory rate--which will result in a precipitous drop in systemic pH and can lead to the severely acidotic patient decompensating and dying within minutes. Instead, those patients, if ventilated, should be hyperventilated to maintain systemic pH.
Bagging/Breathing: The traditional approach for a patient who is crashing is to bag the patient or give mouth to mouth resuscitation. However, "we have gone away from emphasizing airway in patients within the first 10 minutes of cardiac arrest, instead focusing on compressions and early defibrillation," Dr. Mattu noted.
Baby: When a crashing female patient of childbearing age arrives in the ED, "you have to always assume the cause is a ruptured ectopic pregnancy until proven otherwise," Dr. Mattu said. For the pregnant woman with a ventricular arrhythmia, amiodarone should be avoided; but cardioversion is considered safe and a patient can be shocked if necessary at any stage of pregnancy, because very little electrical current reaches the uterus.
Compressions: "We need to focus on the basics, because compression does make a difference," Dr. Mattu said at the meeting. The emphasis on compressions includes making the most out of basic techniques, using the proper compression rate of 100 per minute (the rate recommended by the American Heart Association) and minimizing interruptions, with early defibrillation when indicated, he said.
Cooling: "How many people are at hospitals that have hypothermia protocols in place?" Dr. Mattu asked the audience. Although many hands went up, he responded, "We want to see ALL the hands go up." Cooling to 32°-34° C (about 90°-93° F) for unconscious adults with return of spontaneous circulation after out-of-hospital ventricular fibrillation arrest is now recommended by the International Liaison Committee on Resuscitation (ILCOR), based on two studies.
"Decline position" (Trendelenburg): This position, traditionally recommended for patients in shock to increase blood pressure and/or cardiac output, "simply doesn't work ... and may make patients a little worse," he said. It can actually reduce cardiac output in hypotensive patients. In fact, he noted, one study showed that putting a patient into the Trendelenburg position puts only 1.8% of a patient's blood back into general body circulation.
Defibrillation: There is now much less emphasis on drugs during the first part of resuscitation. "The bottom line is that when somebody is in ventricular fibrillation or in asystole, there are no drugs that have been shown to work," Dr. Mattu said. He also pointed out that biphasic defibrillators and the more traditional, less-expensive monophasic defibrillators are now considered equivalent in terms of outcome. In 2005, the AHA published their most recent guidelines stating that neither type had been consistently associated with superior outcomes after cardiac arrest.
Keep an eye out for the emergence of "hands-on defibrillation," Dr. Mattu added; "There's increasing literature about this." Using a biphasic defibrillator with pre-gel-coated pads while wearing normal clothes appears to expose rescuers to only low levels of leakage current--thus potentially allowing uninterrupted chest compressions.
Effusion and Embolus (pericardial effusion and pulmonary embolus): Pericardial effusion and pulmonary embolus have similar presentations, but "treatments are almost polar opposites," he said. Patients with a massive pulmonary embolus and those with a massive pericardial effusion often have similar risk factors and tend to both present with tachycardia, tachypnea, and shortness of breath. But a pulmonary embolus is treated with anticoagulants, or in some cases with thrombolysis, which can induce a hemorrhagic tamponade in a patient with a pericardial effusion, Dr. Mattu pointed out.
"E" can also stand for "echo"--as in bedside ultrasound. Even when an emergency physician only has basic ultrasound skills, Dr. Mattu said, an ultrasound can distinguish between a large pulmonary embolus or large pericardial effusion. "When you've got somebody who looks really, really sick, always get that ultrasound and take a look at the heart and abdomen, which oftentimes, can provide you with lifesaving information," he recommended.
He also offered tips for another "E": ECG. When you see the combination of tachycardia and low voltage on an ECG, "think pericardial effusion," he said. And T-wave inversions should be considered indicative of pulmonary embolism until proven otherwise.
Beware intubation in potential tamponade patients, Dr. Mattu cautioned. "If you intubate a patient with a potential tamponade, the patient will drop their blood pressure significantly."
- "Forget about it!": "In cardiac arrest, there no antiarrhythmics shown to work," Dr. Mattu cautioned. The list of agents to forget about using includes drugs now known not to work in cardiac arrest, such as high-dose epinephrine, vasopressors, and all of the antidysrhythmics, including amiodarone, none of which has been found to be effective in pulseless ventricular tachycardia or ventricular fibrillation, in terms of survival to hospital discharge