The Plunger, Fine Tuned
Use of an active compression-decompression device combined with an inspiratory impedance threshold device improved 1-hour and 24-hour survival in 103 patients who received that form of cardiopulmonary resuscitation (CPR) versus 107 who received standard CPR, according to researchers in this week’s issue of the journal Circulation (Circulation. 2003;108:2201–2205OpenUrl).
The active compression-decompression device is handheld, with a suction cup that attaches to the chest and a gauge that helps evaluate the force needed for effective compression and decompression, which creates a vacuum within the chest. The vacuum draws more blood back into the heart, which then results in more blood flowing out during compression. Sometimes, air that is drawn in during decompression can reduce the volume of blood drawn into the heart.
The impedance threshold device is a small, 35-mL device that fits on a face mask or an endotracheal tube. Its pressure-sensitive valves limit the inflow of air during chest decompression, allowing more blood to come into the thorax area, noted the researchers, who were led by Benno B. Wolcke, MD, of the Johannes Gutenberg University Medical School Clinic of Anesthesiology in Mainz, Germany.
Keith G. Lurie, MD, the developer of the active compression-decompression and impedance threshold devices, is a coauthor on the article and developed the technology in collaboration with Advanced Circulatory Systems, Inc, of Eden Prairie, Minn. Dr Lurie is now with the Department of Emergency Medicine at the University of Minnesota and Hennepin County Medical Center in Minneapolis. Also collaborating on the article was the Leopold-Franzens Institute of Innsbruck, Austria.
The study was performed in Mainz, Germany, where emergency response included early defibrillation. The patients were sequentially randomized to the two CPR methods by the advanced life support teams after undergoing intubation. Return of spontaneous circulation was seen in 55% of the patients receiving the active compression-decompression accompanied by the impedance threshold device, compared with 37% of those who received standard CPR. Fifty-one percent of the active compression-decompression group lived at least 1 hour, compared with 32% of the standard CPR group; 37% lived 24 hours in the active compression group, compared with 22% of the standard CPR group. In witness arrests, the 1- and 24-hour survival rates were 55% and 41%, respectively, in the active compression group, compared with 33% and 23% in the standard CPR subjects.
In the active compression group, 18% of patients survived to hospital discharge, compared with 13% in the standard CPR group, but the difference was not statistically significant. The authors concluded that active compression-decompression CPR with an inspiratory impedance threshold device improved short-term survival in patients with an out-of-hospital cardiac arrest but that the long-term benefits required further study.
Statins and Clopidogrel—A Good Mix
Despite earlier concerns, giving statins with clopidogrel does not interfere with antiplatelet activity, especially when clopidogrel is given in a high loading dose of 600 mg, said researchers from the Technische Universität in Munich, Germany, in this week’s issue of the journal Circulation (Circulation. 2003;108:2195–2197OpenUrl).
Led by Iris Müller, MD, of Technische Universität in Munich, Germany, the researchers randomized 77 patients with stable angina scheduled for nonemergency coronary stenting to receive atorvastatin, fluvastatin, lovastatin, pravastatin, simvastatin, cerivastatin, or placebo plus a high loading dose of 600 mg of clopidogrel. Platelet aggregation was measured before and 2 and 4 hours after the clopidogrel was given. All patients were on 100 mg of aspirin per day. The researchers said that measurements showed that none of the statins significantly influenced the inhibition of platelet aggregation by clopidogrel.
The authors noted: “The present study cannot rule out the possibility that long-term administration of statins may interfere with clopidogrel. However, recent data from the Interaction of Atorvastatin and Clopidogrel Trial show that atorvastatin does not affect the antiplatelet properties of clopidogrel in patients treated with statins for 30 days.”
Aspirin Withdrawal More Than a Headache
If patients with coronary artery disease stop taking aspirin, they run the risk of developing coronary events associated with withdrawal of the medicine, said researchers from the University Hospital Pasteur in Nice, France, at the recent meeting of CHEST 2003, the 69th annual international scientific assembly of the American College of Chest Physicians, held in Orlando, Fla, October 25 through 30, 2003.
The French researchers, led by Emile Ferrari, MD, Professor of Cardiology at the French hospital, reviewed cases of 1236 patients hospitalized for coronary syndromes. Of those, 51 patients had acute coronary events, including unstable angina, stent thrombosis, and myocardial infarction, less than a week after stopping their aspirin. None of the patients had had an unstable coronary event before they withdrew from aspirin. They stopped for a variety of reasons, including minor surgery, dental treatment, and simple noncompliance with medication instructions, the authors noted.
“Coronary patients preparing for dental work or surgery are often advised to stop taking aspirin in order to avoid increased bleeding,” said Dr Ferrari. “Our study serves as a reminder for all medical professionals who treat coronary patients that aspirin withdrawal should not be advised, and that alternative recommendations should be considered.”
The study “sends a message to all medical professionals that the decision to discontinue aspirin therapy should not be taken lightly,” said Richard S. Irwin, MD, President of the American College of Chest Physicians, in a released statement.
Unnoticed Heart Disease Associated With Later Poor Health
Heart disease that goes undetected may be associated with poorer health in old age, said researchers from the University of Pittsburgh School of Medicine in a report in the October 27, 2003, issue of the Archives of Internal Medicine (Arch Intern Med. 2003;163:2315–2322OpenUrlCrossRefPubMed).
The researchers, led by Anne B. Newman, MD, MPH, of the University of Pittsburgh School of Medicine, studied 2932 men and women aged 65 and older who were free of cardiovascular disease, cancer, and chronic obstructive pulmonary disease and had intact physical and mental function. All could perform the activities of daily living. The subjects were followed up for 8 years to determine if they maintained their health.
The presence of subclinical heart disease was determined by baseline tests such as ultrasound of the carotid artery and electrocardiograms. Forty-eight percent of the subjects continued to be healthy during the follow-up period. The factors most likely to affect their status were less subclinical heart disease and younger age at the start of the study, the researchers noted. They noted that the presence of subclinical heart disease was associated with 6.5 years of aging for the women and. 5.6 years for the men.