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Lies, damned lies, and bloody lies.
Jul. 2nd, 2008 12:55 pmI caught last night's file on four. It was an interesting discussion on recent theories involving the use of stored red blood cells.
IIRC They tend to be stored for between 10 to 30 days before being given to someone. Scientist know the cells change slightly with storage. For instance they become less flexible, so cannot fit down the smallest capillaries as easily. They can take up to a day to recover.
A lot of blood goes to people who've lost red cells through traumatic accidents, surgery, complications in birth, and haematology (leukaemia, chemotherapy, bone marrow transfers, etc.), and no-one disputes this saves lives. But some goes to people who read as anaemic on charts, or as a precaution during elective surgery, and the debate was around the benefits to this group, and the length of storage of blood.
Ben Goldacre would have liked it, as there was lots of discussions of methodology, and statistical evidence.
Both main participants were in favour of funding a proper randomized controlled trial, but disagreed on the validity of the retrospective study that had already been taken place. This study had found that people who receive older blood are more likely to have complications than people who hadn't
Participant 1 said that the retrospective study wasn't valid as the patients weren't randomised, and generally sicker people who receive blood in the first place. This would only affect the 10% who didn't fall trauma/surgery/birth/haematology group. So we should continue current practice while further evidence is gathered.
Participant 2 said that 30% of blood goes to people who haven't lost it in trauma/surgery/birth. And that they had taken account of the effects of the level of illness properly in their study, so we should stop storing blood for as long.
I don't have time to go through all the literature myself, but I know who I trust more at the moment. The scientist who didn't spin the statistics by leaving out haematology patients, and deflecting the question ("Yes, but the research is important because...") when confronted on it.
IIRC They tend to be stored for between 10 to 30 days before being given to someone. Scientist know the cells change slightly with storage. For instance they become less flexible, so cannot fit down the smallest capillaries as easily. They can take up to a day to recover.
A lot of blood goes to people who've lost red cells through traumatic accidents, surgery, complications in birth, and haematology (leukaemia, chemotherapy, bone marrow transfers, etc.), and no-one disputes this saves lives. But some goes to people who read as anaemic on charts, or as a precaution during elective surgery, and the debate was around the benefits to this group, and the length of storage of blood.
Ben Goldacre would have liked it, as there was lots of discussions of methodology, and statistical evidence.
Both main participants were in favour of funding a proper randomized controlled trial, but disagreed on the validity of the retrospective study that had already been taken place. This study had found that people who receive older blood are more likely to have complications than people who hadn't
Participant 1 said that the retrospective study wasn't valid as the patients weren't randomised, and generally sicker people who receive blood in the first place. This would only affect the 10% who didn't fall trauma/surgery/birth/haematology group. So we should continue current practice while further evidence is gathered.
Participant 2 said that 30% of blood goes to people who haven't lost it in trauma/surgery/birth. And that they had taken account of the effects of the level of illness properly in their study, so we should stop storing blood for as long.
I don't have time to go through all the literature myself, but I know who I trust more at the moment. The scientist who didn't spin the statistics by leaving out haematology patients, and deflecting the question ("Yes, but the research is important because...") when confronted on it.
