12 May 2004

Patients in intensive care may have undiagnosed deep vein thrombosis

Patients in intensive care units are particularly vulnerable to deep vein thrombosis (DVT) and the potentially fatal pulmonary embolism that can ensue from DVT, yet intensivists frequently fail to spot these conditions. An article published this week in Critical Care explores how clinicians think about DVT in the ICU setting, where the diagnostic criteria typically used in mobile patients may not apply.

Generally, DVT is diagnosed in mobile patients after they report leg pain or a swelling in one leg, and a radiological examination shows a blockage in a blood vessel. As critically ill patients are less able to report symptoms, and as they often have swollen legs as a result of their critical illness, DVT may go unnoticed.

To help devise a new strategy for assessing the importance of DVT in intensive care patients, researchers from McMaster University and the University of Toronto asked 71 physicians to rate different factors according to their importance in deciding whether DVT was likely to lead to short- or long-term illness, or death in critically ill patients.

The physicians, from the Canadian Critical Care Trials Group, reported that they were most likely to take DVT seriously if the patient showed leg signs that were suggestive of a blood clot, if the patient already had acute or chronic cardiopulmonary problems, or if they had a suspicion that the patient was suffering from pulmonary embolism. The physicians concern was likely to be heightened if an ultrasound scan showed the patient to have a large thrombosis in the thigh region that completely blocked the blood vessel.

Deep vein thrombosis, especially in the thigh, frequently leads to pulmonary embolism. According to the authors of the study, "in critically ill patients [...], a small pulmonary embolism, which might be of minimal clinical importance in less ill patients, might have severe or fatal consequences."

The low tolerance of even small pulmonary embolisms in these patients lead the authors to wonder whether there is a role for routine ultrasound screening for DVT in intensive care units. Similar programmes that screen less ill patients upon discharge from hospital were abandoned after being shown to be ineffective, but the researchers urge that caution is needed in extrapolating these negative results to schemes for critically ill patients.

Meanwhile, physicians need to maintain a high level of suspicion of blood clots in seriously ill patients, and effective preventive strategies are needed.

Patients in intensive care are highly susceptible to DVT as they are immobile for long periods of time, and frequently have catheters and/or need surgery - three major risk factors for the condition.

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This press release is based on the following article:

Clinically important deep vein thrombosis in the ICU: A survey of intensivists
Deborah Cook, Maureen Meade, Gordon Guyatt, Lauren Griffith, John Granton, William Geerts and Mark Crowther
Critical Care 2004, 8:R145-R152

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For further information about this study, contact Deborah Cook by e-mail at debcook@mcmaster.ca or by phone on +1 905 525 9140 x 22900

Alternatively, or for more information about the journal or Open Access publishing, contact Gemma Bradley by phone on +44 207 323 0323

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Critical Care (http://ccforum.com/) is published by BioMed Central (http://www.biomedcentral.com), an independent online publishing house committed to providing Open Access to peer-reviewed biological and medical research. This commitment is based on the view that immediate free access to research and the ability to freely archive and reuse published information is essential to the rapid and efficient communication of science. BioMed Central currently publishes over 100 journals across biology and medicine. In addition to open-access original research, BioMed Central also publishes reviews, commentaries and other non-original-research content. Depending on the policies of the individual journal, this content may be open access or provided only to subscribers.