Transcutaneous oximetry and skin surface temperature as objective measures of pressure ulcer risk

To determine if transcutaneous oximetry and skin surface temperature could measure differences in skin perfusion between 2 groups of hospitalized patients: (1) those who made gross or subtle movements in bed, and (2) those who could not move.

A quasi-experimental design was used.

A convenience sample of 38 subjects (17 males, 21 females) was selected from patients admitted to a neurological/neurosurgical critical care and step-down unit in a university health sciences center hospital.

Prepressure and postpressure oximetry and temperature readings were taken over the sacrum and recorded every minute for 15 minutes. Pressure was applied by positioning subjects on their backs for 2 hours; subjects were observed for gross or subtle movement. Oximetry measurements were taken and recorded every minute.

Paired t tests showed subjects who moved (n = 24) had a statistically significant difference between prepressure and postpressure temperature means over subjects who could not move (n = 14). Postpressure transcutaneous carbon dioxide (TcPCO2) mean levels were lower at all time-points and transcutaneous oxygen (TcPO2) mean levels were higher at most time-points in subjects who moved. Analysis of variance between the 2 groups during pressure showed a statistically significant difference in TcPCO2 levels, but not TcPO2 levels.

Both methods identified statistically significant differences in moving and nonmoving patients and may prove to be useful tools in assessing pressure ulcer risk. Further research with both methods across various patient populations is needed.