A Michigan study states that all those severely down with the H1N1 influenza, swine flu, are at a higher risk of developing blood clots in their lungs.

A blood clot in lungs is usually called pulmonary [pertains to lungs and respiratory system] embolism, a condition that occurs when one or more arteries in the lungs gets blocked.

The findings of the study suggested that in the wake of H1N1 virus's potential complications, medical practitioners, especially the radiologists, will have to be more aware to look closely for the risks of pulmonary embolism in severely sick patients.

Experts say that a blood clot in lung can also cause low oxygen levels in the blood and damage vital organs in the body because of lack of oxygen. The patient can feel light headed or chest pain and can also die as a result. However, they say that blood-thinning drugs can reduce the risk of death in such conditions.

Study and its findings
Researchers based at the University of Michigan, U.S., examined the medical condition
of 66 patients diagnosed with the H1N1 swine flu. Of these, 14 patients were severely ill with the H1N1 infection. Due to their severe medical condition, they had to be admitted to the intensive-care unit.

In order to identify the risk caused by the lethal H1N1 virus, all 66 patients underwent CT [a non-invasive procedure that takes cross-sectional images of the brain or other internal organs; to detect any abnormalities that may not show up on an ordinary x-ray.] scans--medical imaging method using computer processing--to look for any complications caused by the pandemic flu.

Reports of the CT scans detected pulmonary embolisms in five of the 14 intensive-care unit patients. However, the researchers maintained that initial standard chest X-rays were normal in more than half of the patients with H1N1 infections.

"These findings indicate that imaging studies would have to be repeated in severely ill patients to monitor disease progression," said study co-author Dr. Ella Kazerooni, director of the University of Michigan's division of cardiothoracic radiology. "It's important to heighten awareness not only among the radiologists, but also among the referring clinicians."

The researchers noted that more sophisticated CT scans are needed to diagnose the potentially fatal condition since the standard chest X-rays cannot effectively scan the lungs.

A report by World Health Organisation (WHO) also warns that the H1N1 might return for a second strike in winters in a more mutated form, infecting the lungs deeper this time.