The microclimate under dressings applied to intact weight-bearing skin: Infrared thermography studies.

BACKGROUND: When a patient is lying in a hospital bed (e.g. supine or prone), bodyweight forces distort soft tissues by compression, tension and shear, and may lead to the onset of pressure ulcers in those who are stationary and insensate, especially at their pelvic region. Altered localized microclimate conditions, particularly elevated skin temperatures leading to perspiration and resulting in skin moisture or wetness, are known to further increase the risk for pressure ulcers, which is already high in immobile patients. METHODS: We have used infrared thermography to measure local skin temperatures at the buttocks of supine healthy subjects, to quantitatively determine, for the first time in the literature, how skin microclimate conditions associated with a weight-bearing Fowler's position are affected by application of dressings. Our present methodology has been applied to compare a polymeric membrane dressing versus placebo foam, with a no-dressing case used as reference. FINDINGS: One hour of lying in a Fowler's position was already enough to cause considerable heat trapping (~3 °C rise) between the weight-bearing body and the support surface. Analyses of normalized local skin temperatures and entropy of the temperature distributions indicated that the polymeric membrane dressing material allowed better and more homogenous clearance of locally accumulated body-heat with respect to simple foam. INTERPRETATION: Infrared thermography is suitable for characterizing skin microclimate conditions under different dressings, and, accordingly, is effective in developing and evaluating pressure ulcer prevention and treatment strategies - both of which require adequate skin microclimate.

Which endotracheal tube location minimises the device-related pressure ulcer risk: The centre or a corner of the mouth?

The use of an endotracheal tube (ETT), which is required for any mechanical ventilation procedure, involves an inherent risk for facial skin, lip, and mucosal pressure ulcers. The ETT is one of the most common devices associated with medical device-related pressure ulcers (MDRPUs) among surgical and intensive care unit patients. In the present work, we investigated, for the first time in the literature, the biomechanical effects of the presence and positioning of an ETT in the mouth on lip, mucosal and surrounding facial skin loads. Using two anatomically realistic finite element model variants, two ETT locations were simulated and compared, at the centre versus the corner of the mouth. Our study shows that a central location of the ETT inflicted greater lip and mucosal stress values, but a corner location caused a more widespread and diffused lip, mucosal and facial skin stress exposure. Accordingly, we cannot recommend a "safer" location for ETTs in the mouth; additional preventative measures such as dedicated dressing materials or special cushioning pads applied prophylactically, should be developed to protect from MDRPUs associated with ETT usage. The present modelling framework can be used to study the biomechanical efficacy of such protective technologies, and can therefore aid in the prevention of ETT-caused MDRPUs.