A randomized controlled trial evaluated the impact of different methods of water agitation on clinical and microbiological outcomes in 31 nursing home residents. Four conditions were tested: a) whirlpool tub, jets on, using standard soap products; b) ultrasound tub, ultrasound on, using the standard soap products; c) ultrasound tub, ultrasound on, using specialized soap and skin conditioner; and d) either tub (randomized), water circulation off, using standard soap products (the control condition). Outcomes of interest included skin microbial flora, water microbial flora, skin condition, time spent bathing, and staff satisfaction.

Resident skin condition and skin microbial flora did not differ between the four treatments. The tubs also did not differ in terms of bacterial colonization; however, there was a non-statistically significant trend for the highest counts to occur in whirlpool tubs after being idle overnight. The ultrasound and whirlpool tubs were preferred by staff over the control treatment (still water) in terms of sound and overall suitability. In addition, staff reported that the ultrasound tub using enhanced skin cleansers made bathing residents easier and faster than the same tub using standard cleansers.