Cardiac monitor may aid critical burn patients
Necessary data obtained at reduced risk
A new cardiac monitoring system seems to improve the care of critically ill burn victims while minimizing the risk, according to early anecdotal data gathered at the University of North Carolina School of Medicine in Chapel Hill. Doctors and nurses at the N.C. Jaycee Burn Center are among the first in the country to use the PiCCO system in treating burn patients. The monitoring system, manufactured by Pulsion Medical Systems AG, of Munich, Germany, was approved by the Food and Drug Administration (FDA) in May 2001.
"This is not a study," asserts Bruce A. Cairns, MD, an assistant professor of surgery specializing in trauma, critical care, and burns at the UNC School of Medicine. "We would like to eventually do a study, but the whole impetus was the fact that we were able to introduce the catheter and immediately recognize benefits, particularly among the nursing staff, that without analysis seemed fairly evident."
According to Loree Farber, RN, nurse education clinician for the burn center, using older cardiac function monitoring technology calls for many more steps, including insertion of a wire through the pulmonary artery across the right side of the heart with the subsequent risk of artery damage and bloodstream infection. Risk of the latter is increased in the critically ill; burn patients typically have a high bloodstream infection risk from catheterization.
"It also means bringing another box and more equipment into the room vs. having one little module to stick into our monitor, which is less invasive and calls for less complicated steps," Farber says. "The information is integrated on the screen and all you have is one wire and one box. With the PiCCO and its continuous numbers, physicians can just look at the monitor and get as much information as they need."
How the monitor works
The PiCCO involves the insertion of a very thin catheter into the femoral artery. The catheter is thin enough to use in children, and as light as 4.4 pounds. The system makes calculations of cardiac output function based on information obtained from within the artery rather than having to float a catheter through the heart, as is done with the widely used Swann-Ganz catheter.
With standard cardiac monitoring systems, cool saline fluid is injected through the Swann-Ganz catheter. Temperature changes are calculated and entered into a formula, from which a representation of cardiac function is derived. "In combination with the blood pressure measurement, other calculations can be made to come up with a picture of the blood profusion in the body," Cairns explains. Thus, when doctors need more data, nurses must inject more fluid and derive new calculations.
"This newer arterial catheter is not floated through the heart and into the lung, the pulmonary venous system," says Cairns. "It can measure temperature differences at the level of the artery rather than at the pulmonary arterial level. Therefore, with PiCCO, we can place an arterial catheter that functions almost identically as the Swann-Ganz catheter but without the risks. And the PiCCO module can let us observe real-time cardiac output changes, real-time cardiovascular and volumetric monitoring that’s never been available before."
Despite the positive first impressions, Cairns emphasizes that he is interested in better defining the effectiveness of this new device. "There are a whole lot of things that need to be answered before we jump in on this," he cautions.
A number of validation studies have been conducted in Europe, he notes, which have shown that this monitoring system would be equivalent to the Swann-Ganz parameters. "We wanted to confirm for ourselves that this was the case," says Cairns, "And our analysis was that the Swann-Ganz parameters were equivalent. At least that was the original assessment."
The main advantage Cairns sees so far is the ability to get the same amount of information while minimizing the amount of effort required and minimizing the risk to the patient. "That was really the purpose of looking at this device," he explains. "In addition, while we are still in the process of reviewing our information, we believe there will be a substantial cost advantage."
Most burn patients do not require the highest levels of cardiac monitoring, Cairns notes, but the high-risk patients are precisely the cases that represent the greatest potential value if you can obtain the same information with less intervention. "The inherent attractiveness of this alternative is if all we do is put in the same catheter and central lines and get similar information without having to put in the Swann-Ganz, you would have an impetus to consider that alternative," Cairns says.
The device has been approved by the FDA because it is safe and accurate for what it proposes to do, Cairns explains. "Whether or not others will find it as useful and as cost-effective as we appear to is what we are trying to evaluate," he observes. "There is a great deal of enthusiasm on the part of our nursing staff, and when you talk about the ICU staff for treating burn victims, they are the critical element."
The PiCCO can be used in virtually any facility, says Cairns. "One of the things I find so interesting is how easy it was to introduce to the nurses," he notes. "It has been one of the few introductions of technology here that have been universally accepted by both the nursing staff and the physician staff."
Need more information?
For more information, contact: Bruce A. Cairns, MD, Campus Box 7210, Department of Surgery, UNC School of Medicine, Chapel Hill, NC 27599-7210. Telephone: (919) 966-0078.
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