[Definition and validation of a comfort index calculation method for office seats]

BACKGROUND

Among its other required features, a highly comfortable chair should adapt its contact surfaces, namely the seat and the back rest, to the shape of the body of the person sitting on it. However, "comfort" is not usually perceived as an absolute value, but is derived from a subjective comparison between two or more chairs.

OBJECTIVES

The purpose of this research was the definition of an objective comfort index (IC), i.e., derived from instrumental measurements, and which would also represent an absolute comfort value.

METHODS

Analytical evaluation of the distribution of body weight, by means of a barometric matrix, shows that a comfortable chair tends to minimize peak and average values of pressure at the level of the contact areas located between the body and the seat and the back of the chair. To define a comparison parameter for determining an absolute comfort value, a reference chair (SDR) was developed. The seat and the back of this chair are rigid, with poor compliance. A comfort value of zero was, by definition, assigned to this chair. Therefore, the Comfort index (IC) was obtained by the mathematical calculation of the ratios of averages, peaks and gradients of pressure, appropriately weighted, and the corresponding values measured on the tested chair and on the SDR.

RESULTS

It is shown that the anthropometric characteristics of each subject are irrelevant to the assessment of the IC, which depends only on the compliance characteristics of the seat and back surfaces of the tested chair

CONCLUSIONS

IC can be improved through analysis of a larger number of seats, which would thus constitute the basis for the use of an objective evaluation of seating comfort.

[Strategies to face the shortage of nurses in 11 health settings: descriptive analysis]

A survey on the perceived severity and criteria for defining the nursing shortage was made by interviewing with a semistructured questionnaire 11 nurses responsible for nursing services of 11 Italian hospitals and districts. The questionnaire was administered by interview. Ten hospitals suffer a medium-severe nursing shortage. The main solutions adopted to overcome the nursing shortage are: the closure of wards, the merge of wards, with comparable patients; the employment of support personnel; the mobility of nursing personnel, whereby nurses change wards and are move where they are most needed; modification of shifts. Interestingly, criteria for defining the nursing shortage vary from hospital to hospital, but they are not based on objective data (c.g. number of "missing" nurses). The payment of overtime hours is also different, ranging from 20 to 35 dollars/hour. Since the shortage of nurses will last for the next 5-8 years, a study of criteria for assessing it, of solutions adopted and of their effectiveness is pivotal for gaining a better understanding of the problem.