Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Simple formula predicts blood needs in heart surgery

02.05.2006


Duke University Medical Center researchers have developed a simple formula that will enable anesthesiologists to predict, based on individual patient characteristics, how much blood to have on hand in the operating room prior to coronary artery bypass surgery.



The new formula not only can save hospital resources and staff time, but also can lead to a more rational allocation of banked blood, according to the researchers.

Before a bypass procedure, blood typically is delivered to the operating room in case it will be needed to replace blood lost during surgery. But not just any blood will do. The reserve blood must be matched with the patient’s blood type, and it also must be "cross-matched." In cross-matching, a small amount of the patient’s blood is mixed with a small portion of banked blood to test for adverse immunological reactions.


In their study, the Duke researchers found that the patients who are most likely to need the most blood during or immediately following their surgery are those who are over the age of 75, those who have impaired kidney function and those who weigh less than 121 pounds.

"At most U.S. hospitals, four units of typed and cross-matched blood are routinely sent to the operating room at the time of surgery," said George Lappas, M.D., a cardiovascular anesthesiology fellow who presented the Duke team’s results on May 1, 2006, at the annual scientific sessions of the Society of Cardiovascular Anesthesiologists. "This is the arbitrary amount that has been used for many years in operating rooms nationwide."

"We thought there needed to be a better way to estimate blood needs, since blood is a scarce commodity that takes staff times and resources to prepare," Lappas said. "Also, with blood being held in operating rooms ’just in case,’ it is not available for other patients who might need it."

The savings to hospitals and blood banks would be realized primarily in the reduced costs and manpower involved in the cross-matching process, Lappas said. On average, it costs about $55 to cross-match each unit of blood, meaning that $220 is typically spent for every surgery, whether the blood is used or not, he said.

The team’s research was supported by Duke’s Department of Anesthesiology.

In their study, the researchers analyzed the charts of 5,402 consecutive patients who received a bypass procedure at Duke University Hospital between 1993 and 2002. They correlated blood use during the first 24 hours after surgery with 13 different patient characteristics, such as anemia before surgery, age, gender, weight, heart and kidney function, tobacco use and other accompanying illnesses.

For the first two-thirds of the patients, they determined which characteristics led to greater blood use. They then developed the formula based on those findings and tested its predictive abilities on the last third of patients.

"We confirmed our hypothesis that a model based on a patient’s characteristics prior to surgery could predict how much blood would need to be cross-matched prior to surgery," Lappas said. "This approach would appear to be a more rational and scientifically based approach for predicting blood needs."

The simplified scoring system devised by the team would identify risk factors for transfusion. For example, 1.5 units of cross-matched blood would be made available for patients older than 75, weighing less than 121 pounds or having a creatinine level of more than 1.4. Creatinine is a normal byproduct of metabolism; higher-than-normal levels in the blood indicate an impairment of the kidney’s filtering ability, because kidneys normally filter creatinine out of the blood and excrete it in the urine.

Other factors, such as age older than 65, female sex or anemia (a hematocrit of less than 36 percent), would need one additional unit of cross-matched blood. Hematocrit is a measurement of the percentage of oxygen-carrying red blood cells in the blood; normal hematocrit ranges between 36 percent and 40 percent. An additional half unit of blood would be supplied for patients who have creatinine levels of greater than 1.2, who weigh less than 187 pounds, or whose heart function is moderately impaired.

To determine how many units of blood to set aside for an individual about to undergo surgery, physicians would add up all of the amounts for that person’s applicable characteristics.

"We believe this model could easily be used by any hospital’s blood bank to allocate blood in a more safe and cost-effective manner," Lappas said. "The formula is simple and easy to use."

Other members of the Duke team were Barbara Phillips-Bute and Mark Stafford-Smith.

Richard Merritt | EurekAlert!
Further information:
http://www.mc.duke.edu

More articles from Health and Medicine:

nachricht New malaria analysis method reveals disease severity in minutes
14.08.2017 | University of British Columbia

nachricht New type of blood cells work as indicators of autoimmunity
14.08.2017 | Instituto de Medicina Molecular

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

Gold shines through properties of nano biosensors

17.08.2017 | Physics and Astronomy

Greenland ice flow likely to speed up: New data assert glaciers move over sediment, which gets more slippery as it gets wetter

17.08.2017 | Earth Sciences

Mars 2020 mission to use smart methods to seek signs of past life

17.08.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>