Monday, January 10, 2011

Does Fluid Resuscitation Harm Trauma Patients?

A study published on line ahead of print in Annals of Surgery has attracted attention as it purportedly shows that trauma victims who received intravenous [IV] fluids in the pre-hospital setting fared worse than those who did not. Media outlets such as USA Today, the LA Times and Bloomberg Business Week all reported the findings uncritically. In fact, one version of the HealthDay story quoted the conclusion of the paper’s abstract which definitively states that IV fluids should not be used. That is why reading only abstracts can be misleading.

While I tend to agree with the premise that IV fluid administration might raise the blood pressure and actually promote further bleeding, the paper’s conclusion that the routine use of IV fluid resuscitation for all trauma patients should be discouraged is not supported by its data.

Here are some of the problems with the paper:

1. The paper is based on data from the National Trauma Data Bank, a voluntary database contributed to by over 600 trauma centers. The data may not be entirely reliable. For example, the paper reviewed data from the years 2001-2005. Of 1,466,887 possible patients, only 776,734 (53%) had pre-hospital data to review.
2. The only mention of an IV in the raw data is whether or not an intravenous catheter was inserted. The database contained no information on the amount of IV fluid given at the scene of the trauma, during transport to the hospital or even in the emergency department. This renders the title of the paper “Prehospital Intravenous Fluid Administration is Associated With Higher Mortality in Trauma Patients: A National Trauma Data Bank Analysis” somewhat suspect.
3. During the years studied, scene and transport times were not collected. It is possible that the problem leading to the poorer outcomes in the patients who had IV lines placed is increased time wasted at the scene and not necessarily the IV fluid itself.
4. According to the database, more than half of the patients who had an IV started also had Military Anti-Shock Trousers [MAST] placed. This is hard to believe since the use of MAST was discredited years ago. And of the patients who did not have an IV inserted, only 0.19% had MAST applied. Perhaps the MAST is doing the damage and not the IV.

I asked the lead author of the study, Dr. Elliott R. Haut, to comment on my criticisms and he said, “I agree that our study is not perfect for some of the reasons you cite and others as well. Retrospective data studies like this are fraught with potential problems and cannot truly define causality. However, I do continue to feel strongly that our study, along with all of the other data on the subject, suggest [sic]that IV fluids are not all benefit without harm. More research needs to occur to figure out the best practices.” This is a much softer statement that that of the abstract of the paper which concluded “The harm associated with prehospital IV fluid administration is significant for victims of trauma. The routine use of prehospital IV fluid administration for all trauma patients should be discouraged."

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