A computerised real-time measurement system to locate the position of the urine stream in designing urine collection devices for women

A computerised real-time measurement system has been developed and tested for locating the position of the urine stream into a handheld urinal and onto a body-worn pad using arrays of resistive or optical sensors. Experimental data indicates that urine streams were usually scattered over quite a large cross-sectional area (typically 30mm in the anterior/posterior direction) at the point of entry into handheld urinals. However, a correctly placed aperture of length 90mm would have successfully received all the urine from the total of 36 clinical experiments run with seven women. Similarly, experiments to determine the initial position of the urine stream onto body-worn pads indicated that a target area of length 120mm would have received the initial stream of urine from all 54 clinical experiments with 18 women. These data have been used to help with the design of a handheld urinal and a body-worn urine collection interface (the latter using the body-worn pad data) to be used in two variants of a new urine collection device for women (NICMS). Although both resistive and optical sensors provided useful data, the reliability of optical sensors was often compromised by droplets of urine splashing onto light sources or detectors. Future work should focus on protecting them from splashing.

A critical investigation of ISO 11948-2 and ISO 11948-1 for predicting the leakage performance of small disposable incontinence pads for lightly incontinent women

ISO 11948-2--an international standard laboratory method developed to predict the leakage performance of small disposable pads for lightly incontinent women--was investigated. The repeatability and reproducibility (precision within and between laboratories, respectively) of two variants on the method were found to be poor. The coefficient of variation for each method variant in each laboratory (two laboratories ran each variant) was higher than 40% for about half the 12 products evaluated. Results differed by up to 94% between laboratories for a given product. The ability of the method to predict the leakage performance of pads was investigated by measuring correlations between the clinical evaluations of the 12 products, and technical evaluations using ISO 11948-2. Correlations were very weak (r < or= 0.487). Accordingly, it is recommended that 11948-2 is withdrawn. A second international standard method (ISO 11948-1)--developed for evaluating large pads, but sometimes used on small ones--was also investigated. Correlations between the clinical evaluations of the 12 products and technical evaluations using ISO 11948-1 were weak (r < or = 0.560). Accordingly, it is recommended that ISO 11948-1 is not used for evaluating small disposable bodyworn pads for women.

How well does ISO 11948-1 (the Rothwell method) for measuring the absorption capacity of incontinence pads in the laboratory correlate with clinical pad performance

The ability of ISO 11948-1 (the Rothwell method) to predict the leakage performance of disposable bodyworn pads for heavy urinary incontinence was investigated by measuring correlations between models based on clinical evaluations of 138 diapers and inserts (the two major design categories), and technical models based on their Rothwell absorption capacities and design features. Correlations were poorer than in the original 1993 study for the standard (r < or =0.87 compared with r < or =0.95), but still strong enough to help with purchasing choices. For a given Rothwell capacity, the leakage performance of diapers was far superior to inserts; for example, diapers containing 450 and 300 g of urine performed, as well as inserts containing 300 and 100 g, respectively. No evidence was found for any other design feature having a significant impact on leakage performance. The coefficient of variation for Rothwell capacity (a measure of product consistency) had significant impact on the leakage performance of diapers, but not inserts. The probability of diapers with the poorest consistency leaking exceeded that for the best by about 10 percentage points. Similarly, diapers were about 10 percentage points more likely to leak when used at night than during the day. Differences between day-time and night-time use of inserts were not studied.

Is there a risk of cross-infection from laundered reusable bedpads?

The risk of cross-infection from reusable incontinence bedpads was assessed by determining their microbial content after one night's use by incontinent adults and after laundering using the standard foul wash procedure specified by the NHS Executive (NHS E, 1995) (which includes heat disinfection at 71 degrees C for 3 minutes). Measurements were made on a total of 145 bedpads from five different product designs. It was found that effective laundering destroyed all known pathogenic organisms, although some commensal flora were isolated in small numbers (mean 12.2 colony forming units/ml). It is concluded that laundering reusable incontinence pads using the foul wash procedure leaves pads safe for multiple patient reuse with no demonstrable risk of cross-infection.