Due to aging characteristics such as dry, loose and inelastic skin, and decreased skin tolerance, the elderly are more vulnerable to injuries caused by pressure. An appropriate decompression mattress is the key to preventing pressure injury.

To compare the decompression effects of two types of mattresses by analyzing the pressures and temperatures of sacrococcygeal skin in bedridden elderly patients in the supine position.

By convenience sampling, 45 bedridden elderly patients who were admitted to Cadre Internal Medicine Ward, General Hospital of Eastern Theater Command from January 2021 to March 2022 were selected as the participants (all of them were male since most of the patients in the ward were male) . They were assigned to group A (n=23, use of gel mattress, repositioned every two hours for seven days) or group B (n=22, use of air mattress, repositioned every two hours for seven days) according to their willingness. The maximal sacrococcygeal pressure and skin temperature were measured at three fixed defined time points every day during supine position〔at the beginning (baseline) , and at one and two hours in the position〕. Maximal sacrococcygeal pressure was measured using a continuous bedside pressure mapping system, and the skin temperature in the same location was measured using a hand-held thermometer. The linear mixed-effects model was used to analyse the changes in sacrococcygeal pressure and skin temperature of the elderly bedridden patients and compare the decompression effects of the two mattresses.

There were no pressure injuries in both groups during the intervention. The interaction effect between group and day was not statistically significant on the changes in sacrococcygeal pressure (F_group*day=0.07, P_group*day=0.999) , while the interaction effect between group and time on them was statistically significant (F_group*time =6.45, P_group*time=0.012) . Therefore, the mixed-effects model analysis was conducted again after removing the interaction between the group and day. The results indicated that the sacrococcygeal pressures in the gel mattress group were lower than those in the air mattress group after one and two hours after the supine position (P<0.05) . For the changes in skin temperature, the interaction effect between group and day was not statistically significant (F_group*day=0.12, P_group*day=0.994) , while the interaction effect between group and time was statistically significant (F_group*time =16.90, P_group*time<0.001) . Therefore, the mixed-effects model analysis for temperature was conducted again after removing the interaction between the group and day. The results demonstrated that the sacrococcygeal pressure changes in the gel mattress group were lower than those in the air mattress group after one and two hours in the supine position (P<0.05) .

Both the sacrococcygeal pressures and skin temperatures of bedridden hospitalized elderly male patients were increased after using the gel mattress or air mattress for one or two hours in supine position. The pressure and skin temperature increments were less from the gel mattress than from the air mattress, indicating that gel mattress was superior to air mattress in mitigating sacrococcygeal pressure and skin temperature.