Background Malnutrition is one of the most common problems found in critically ill patients. It is often associated with increased mortality rate and other complications in an intensive care unit (ICU). Previous studies indicated that 40%–50% of critically ill patients are malnourished and an average of 5 kilogram body weight is lost when they are discharged.

Methods This prospective study was conducted to survey the nutritional status of critically ill patients in the Trauma surgical Intensive Care Unit (ICU Trauma) in Khon Kaen Hospital, Thailand, and identify potential outcomes of malnutrition among these patients. From October 2012 to July 2013, 282 patients were screened with the Nutrition Alert Form (NAF) in the second day of their admission. Higher NAF scores signify poorer nutritional status. The patients were then followed until they were discharged from ICU Trauma.

Results Revealed that, 2 days after admission, over a half of the patients (n = 180, 63.8%) were withheld from oral intake of food and fluids. Moreover, most patients were severely malnourished (n = 240, 85.1%). When considering the success of endotracheal tube (ETT) removal as an outcome of care, it was found that those with successful ETT removal had significantly lower NAF score ( = 13.61, S.D. = 4.4) compared to those who failed ETT extubation ( = 17.08, S.D. = 9.7, t = −3.345, p = 0.001). NAF scores were not different between patients who survived and those who died in this study. These results indicated that critically ill patients are at high risk for malnutrition. Proper nutritional management may lead to improved care outcome such as successful ETT removal.

Conclusions Critical care settings should develop a nutritional management protocol for critically ill patients.