Oral decontamination: Chlorhexidine is the oral antiseptic most rigorously studied with regards to Ventilator-associated pneumonia ; its use has been associated with a reduction in the rates of Ventilator-associated pneumonia in recent systematic reviews and meta-analysis. This effect was most pronounced in patients undergoing cardiac surgery and is highly dependent upon both frequency of administration and the concentration of chlorhexidine (2% is more effective than 0.12 or 0.2%). Unfortunately, the results in non cardiac patients were not as clear and there was no benefit in terms of mortality, number of mechanical ventilation days, or other outcomes.