Can vital signs predict cardiac arrest on the wards? Yes, but...
Researchers at the University of Chicago Medical Center attempting to identify the vital signs that best predict those hospitalized patients at greatest risk for cardiac arrest found that a composite index used in some hospitals to activate a rapid response team and by emergency room physicians to assess the likelihood of a patient dying was a better predictor of cardiac arrest than any single vital sign.
However, because the composite index known as Modified Early Warning Score (MEWS) included vital signs that are poor predictors of cardiac arrest, while excluding others, the researchers called for the development of a tool specifically to predict cardiac arrest risk.
"Rapid response teams have not demonstrated the improvements in patient outcomes that we hoped for, in part because some of the patients who may benefit the most are not identified," said the principal investigator of the study, Matthew Churpek, MD, MPH, a pulmonary and critical care fellow at the University of Chicago. "An objective, evidence-based tool would provide the best way to accurately detect these patients and potentially improve their outcomes."
Dr. Churpek and his colleagues will present the results of their study, "Can Vital Signs Predict Cardiac Arrest on the Wards?" during the ATS 2011 International Conference, in Denver.
The researchers performed a nested case-control study over the course of two years, matching each cardiac arrest patient to four randomly selected controls who were patients in the same unit at the same time. Among the 83 cardiac patients and 332 matched controls approximately 75 percent were medical admissions, the rest surgical.
Case patients were significantly older (mean age 64 ± 17 vs. 60 ± 16; p= 0.03), hospitalized longer prior to suffering cardiac arrest (median 8 vs. 4 days; p=0.02) and more likely to have had a prior rapid response call (13 percent vs. 1 percent, p< 0.001) or icu admission (43 percent vs. 26 percent, p=0.001).
On admission, the case patients and the controls had similar mean vital signs and MEWS, with two significant exceptions: case patients had lower diastolic blood pressure (70 ±19 vs. 75 ± 17) and higher respiratory rates (20 ±3 vs. 19 ±3, p=0.02).
The mean MEWS was significantly higher in patients who would suffer a cardiac arrest within 48 hours than it was for the study's controls, and the difference increased leading up to the event. Although the best predictor in this study, MEWS included variables that were not statistically significant, including temperature, minimum heart rate and systolic blood pressure.
Individual vital signs, including maximum respiratory rate, maximum heart rate, maximum pulse pressure and minimum diastolic blood pressure, were also found to be statistically significant predictors of cardiac arrest. None, though, correlated as highly as MEWS.
The predictive ability of the maximum and minimum vital signs and of MEWS was tested by receiver operating characteristic (ROC) curves, an analysis especially useful in comparing the accuracy of different diagnostic tests.
Although the MEWS performed better than any single vital sign, Dr. Churpek and his colleagues do not believe it is the optimal tool.
"Because current activation systems don't utilize the best vital sign predictors, they often suffer from poor sensitivity and high false-positive rates," explained Dr. Churpek. "This limits the effectiveness of the rapid response team, and the high false-positive rates can lead to 'alarm fatigue' and the wasting of hospital resources."
The creation of an evidence-based cardiac arrest prediction tool, he said, would decrease the false-positive rate and lead to a response system with a better chance of improving patient outcomes. Hospitals would no longer need to choose from the over 50 different published criteria, or make up their own, to determine cardiac arrest risk.
Dr. Churpek and his colleagues believe their study provides important direction to the future creation of an evidence-based system. Several variables, including diastolic blood pressure and pulse pressure, that they investigated are not included in most published rapid response team activation criteria but proved to have predictive ability.
He also noted that the MEWS was similar among patients upon admission but was significantly different 48-hours prior to the event, indicating that there is a window of opportunity for the healthcare team to intervene and improve patient outcomes.
"Rapid response teams are a complex and resource-intensive intervention, so providing evidence-based criteria for their activation is crucial," he concluded "Our patients will do better if we can detect who is at high risk early enough to intervene and prevent a cardiac arrest."
Provided by American Thoracic Society
- In-hospital cardiac arrest occurring during night, weekends may lower patient survival rate Feb 19, 2008 | not rated yet | 0
- Pneumonia patients at risk for in-hospital cardiac arrest May 15, 2011 | not rated yet | 0
- For hospital patients, defibrillation delays mean lower survival Jan 02, 2008 | not rated yet | 0
- Black cardiac arrest patients more likely to be admitted to hospitals with lowest survival rates Apr 29, 2011 | not rated yet | 0
- Cardiac death patients often show symptoms Sep 11, 2006 | not rated yet | 0
- Motion perception revisited: High Phi effect challenges established motion perception assumptions Apr 23, 2013 | 3 / 5 (2) | 2
- Anything you can do I can do better: Neuromolecular foundations of the superiority illusion (Update) Apr 02, 2013 | 4.5 / 5 (11) | 5
- The visual system as economist: Neural resource allocation in visual adaptation Mar 30, 2013 | 5 / 5 (2) | 9
- Separate lives: Neuronal and organismal lifespans decoupled Mar 27, 2013 | 4.9 / 5 (8) | 0
- Sizing things up: The evolutionary neurobiology of scale invariance Feb 28, 2013 | 4.8 / 5 (10) | 14
gravity is std. therefore can we rate a 'mass at height' by watts?
1 hour ago For example.... wind turbines are primarily listed by their wattage (1.5MW etc.) Presumably their output is varied according to rotational speed, so...
Calculating on-axis elements of a solenoid
13 hours ago I wanted to mention that this solenoid has many winds over many layers. The thickness of the windings is 2.4 inches coming off of the engineering...
latitude & longitude & air pressure
15 hours ago Hi there, I have a peculiar question. Imagine that you are in a earth position, obtained by google, that gives you the latitude and longitude....
Differences of Classical Mechanics when learned with Calc vs algebra?
18 hours ago what are the differences? Every example I find usually has a derivative or integral or some kind of calculus defined concept that seems to make it...
what is the distance traveled
22 hours ago A rough sketch of experiment. Image: http://i43.tinypic.com/14t4sk5.png the red dots represent a side view of path traveled, F is downward force...
Image of a Convex Lens Cut in Half Horizontally
May 22, 2013 Hello everyone, A friend of mine came up with this question in class and I really do not have a good answer. Suppose you have a convex lens...
- More from Physics Forums - Classical Physics
More news stories
22 May 2013, Paris, France: The Lotus Valve, a second-generation transcatheter aortic valve implantation (TAVI) device, was successfully implanted in all of the first 60 patients in results from REPRISE II reported at EuroPCR ...
Cardiology 12 minutes ago | not rated yet | 0
Costs to treat stroke are projected to more than double and the number of people having strokes may increase 20 percent by 2030, according to the American Heart Association/American Stroke Association.
Cardiology 23 hours ago | not rated yet | 0
Blood thinners are the preferred treatment option to prevent heart attacks, blood clots and stroke, but they are not without risk, and not just because of their side effects. These high-risk drugs, known as anticoagulants, ...
Cardiology May 22, 2013 | not rated yet | 0
Results from a large observational study reported at EuroPCR 2013 today question whether bivalirudin is superior to heparin in the absence of GPIIb/IIIa blockade, showing similar 30-day mortality in patients with non-ST segment ...
Cardiology May 22, 2013 | 5 / 5 (1) | 0
The DESolve bioresorbable coronary scaffold system achieves good efficacy and safety with low rates of late lumen loss and major coronary adverse events at six months, show first results from the pivotal DESolve Nx trial ...
Cardiology May 22, 2013 | not rated yet | 0
A known difficulty in fighting influenza (flu) is the ability of the flu viruses to mutate and thus evade various medications that were previously found to be effective. Researchers at the Hebrew University of Jerusalem have ...
9 minutes ago | not rated yet | 0 |
A potentially ground-breaking human drug trial is currently underway, which aims to discover whether blood pressure medication can slow or halt the progression of Alzheimer's Disease (AD). This is the latest ...
20 minutes ago | not rated yet | 0
Scientists at Newcastle University have shed new light on how the brain tunes in to relevant information.
1 hour ago | 5 / 5 (1) | 0 |
Professor Michael Jennings, Deputy Director of the Institute for Glycomics at Griffith University, was part of an international team that discovered the previously unknown pathway of how the bacterium colonizes people.
1 hour ago | 5 / 5 (1) | 0 |
(Medical Xpress)—Research by U of T Mississauga psychology professor Glenn Schellenberg reveals that two key personality traits – openness-to-experience and conscientiousness—predict better than IQ ...
1 hour ago | not rated yet | 0 |
(Medical Xpress)—Scientists from the Joint Center for Structural Genomics (JCSG) at SLAC National Accelerator Laboratory have determined the 3-D structure of the chemically active part of an enzyme involved ...
2 hours ago | 5 / 5 (1) | 0 |