• Incidence of PU grade ≥ II [ Time Frame: ICU length of stay ] [ Designated as safety issue: Yes ]
  

• Incidence of major and minor events Time to development of PU grade ≥ II Percentage of implementation by caregivers of scheduled turning Time consumed in repositioning Length of mechanical ventilation Length of ICU stay ICU mortality [ Time Frame: ICU length of stay ] [ Designated as safety issue: Yes ]
  

Pressure ulcers (PUs) pose a major healthcare challenge and are associated with an increased risk of infection and sepsis, longer hospital stay, and higher hospitalization costs. Their reported incidence in critical care patients varies widely from 1% to 56%. Therefore it is important to take appropriate preventive measures, which can often be successful and less costly than the treatment of established ulcers. Among these measures are the use of pressure-reducing surfaces and repositioning strategies in a protocolized way. Though there is general agreement that critical care patients, including those under mechanical ventilation must use pressure-reducing surfaces, there is no enough evidence in the literature about what is the best repositioning schedule when new, high technology mattresses are used. The use of this new technology has lead to propose that repositioning can be less frequent. In the only clinical trial where this subject (time interval turning) has been addressed (Vanderwee et al, Journal of Advanced Nursing), it is concluded that a turning regimen every 4 hours is equally effective than a 2-hour turning, using this kind of mattresses. Nonetheless this study is not made in critically ill patients, that have more risk factors for developing PUs, the reason we don´t share this findings and recommendations cannot be generalized. The study hypothesis is that in patients using APAMs, a turning regimen every 2 hour compared to a 4-hour is most effective in the prevention of PUs and could be equally safe. The objective of this study is to investigate the effect of postural turnings every 2 hours compared to every 4 hours on the incidence of grade > II pressure ulcers (PU) in patients in ICU on mechanical ventilation ≥ 24h that use alternating-pressure air mattresses (APAMs) The study is an open label, randomized, controlled clinical trial. The main variable is the incidence of Pus grade ≥ II. As secondary variables measures of efficacy and safety of patients will be registered. The study will take place in a 26 bed medical-surgical ICU with APAMs. Randomization will be done between 24h-48h from the beginning of MV. The final analysis will be by intention to treat.