Tissue oxygenation and blood flow on specialized and conventional hospital beds

Despite the widespread use of specialty bed products, the physiological mechanism of their benefit has not been evaluated. In this study, healthy subjects were used to study transcutaneous oxygen tension (TcPo2) and laser Doppler blood flow in pressure sore-prone areas on air-fluidized, low-air-loss, and adjustable air-mattress beds relative to a standard hospital mattress with and without an egg-crate mattress overlay. Measurements were obtained over the sacrum with the subject in the prone and supine positions, and over a greater trochanter with the subject in the prone and 90-degree lateral positions. Our results on healthy volunteers suggest that the specialty bed products maintain TcPo2 better than a standard bed when tissue is weighted. Further, the Clinitron had significantly higher TcPo2 when weighted than each of the other beds. Laser Doppler blood flow was much more variable. The weighted trochanter on the standard bed had the lowest blood flow, which is consistent with the TcPo2 readings. However, the variability made the laser Doppler flow data less valuable than the TcPo2. In conclusion, these data indicate that several products, particularly the Clinitron, maintain TcPo2 of weight-bearing tissue, which may be an important mechanism in protecting against pressure sores.