The relationship between dermal pressure ulcers, oxygenation and perfusion in mechanically ventilated patients

More than 1.5 million hospitalized patients develop dermal pressure ulcers (DPUs) annually, which increases cost and prolongs length of stay. Mechanically ventilated patients may be at a high risk for DPU development, but research has not focused on the prevalence of dermal pressure ulcers in this population or the factors associated with dermal pressure ulcer development.

To determine the prevalence of dermal pressure ulcers in subjects receiving mechanical ventilation and to describe the relationship between systemic oxygenation, tissue perfusion, and the prevalence of dermal pressure ulcers.

Subjects from an Intensive Care Unit in a Midwestern hospital in the United States were recruited into this descriptive, correlational study following intubation. Variables included: demographics, general subject status (weight, serum albumin), ventilatory status, oxygenation status (arterial blood gas analysis including concentration of hydrogen ions, partial pressure of carbon dioxide, partial pressure of oxygen, and amount of oxygen carried by hemoglobin), perfusion status (mean arterial pressure, heart rate, urine output), and skin condition. The Braden Scale was used to measure the risk of skin breakdown, with any skin breakdown being classified in stages ranging from I to IV (I having minimal breakdown, IV having maximal breakdown). Braden Scores range from 6 to 23, with a score of 6 indicating high risk and a score of 23 indicating low risk. Data were collected every other day after admission to the Medical Intensive Care Unit until extubation, transfer, or death.

Subjects (n = 40) were primarily Caucasian (77.5%), having a mean age of 56.4 years (+/-14.6 years). Half of the sample was male (50%). Twenty percent of the sample developed DPUs. A Pearson's correlation identified the significant associations between the Braden Score and MAP, PaCO(2), largest weight fluctuation in a 3-day period, and change in weight from admission to discharge. Surprisingly, the lowest Braden Score was not significantly associated with the development of DPUs.

Mechanically ventilated patients are vulnerable to developing dermal pressure ulcers as evidence by 20% of the subject population developing a dermal pressure ulcer. The most significant factors related to a low Braden Score in this group are fluid shifts and fluid weight gain. This may be an important predictor of dermal pressure ulcers not currently assessed clinically.