A standard protocol for all contrast enhanced studies is to ask patients to fast for 4-6 hours prior to the study. Over the years, the fasting is no longer rigorous and reasonable hydration has been recommended to prevent deleterious effects of intravenous contrast on the kidneys (thought that too is debatable).
Nevertheless, it has always been a paradox that while we talk about fasting, we also give 500-1000 cc of oral contrast prior to CT abdomen / pelvis studies.
The reason for people to be fasting has essentially been to reduce the risk of aspiration if there is nausea and vomiting. Given oral contrast in any case makes this reason redundant.
This nice recently published paper examines this issue and compares people who were asked to take a light meal prior to the study versus being asked to come fasting for 4 hours.
It actually finds that those who fast may land up with more problems due to issues with fasting (though their population was an oncology patient population) that those who don’t. Since the incidence of nausea and vomiting in the current era of iso-osmolar intravenous contrast media is low anyway, aspiration was just not an issue.
Perhaps it is time for all of us to examine this practice and to perhaps go easy on fasting instructions.
This is a theme we will keep coming back to again and again. There is yet one more article published this week that discusses how moderate to vigorous physical activity (MVPA) produces substantial health benefits.
This is based on the 2008 Physical Activity Guidelines for Americans that recommends at least 150 minutes per week of moderate of 75 minutes per week of vigorous intensity physical exercise.
This study was done to figure out whether 10 minute bouts of more sustained activity make a difference over and above the usual amount of regular activity. The conclusion the study reached is that it doesn’t matter how the exercise is done, as long as it is done. If these results are correct and replicated, it means that people and trainers can focus on methods of exercise that don’t necessarily include bouts of increased training.
More importantly though, the message again is the same. The more you exercise, the better the mortality benefits are with the benefits tapering off once the exercise levels reach a certain peak (in this case 96 mins / day) for Q3 and 147 mins/day for Q4), though this study measured exercise using an accelerometer and hence also included daily regular activity, rather than a structured activity routine.
In 2012, in the Lancet, Wen CP and Wu H put this in perspective, with this telling graph that shows how physical inactivity is as bad as smoking.
So essentially, we come back to the same refrain. Get off your ass. Do something…anything and it helps.