G. De Vito

Ambulatory blood pressure normality : results from the PAMELA study

Objective To determine ambulatory and home blood pressure means and distributions in relation to clinic blood pressure in a general population. Methods We obtained a random sample of 2400 subjects stratified by sex and 10 year age groups to be representative of residents aged 25–64 years of the city of Monza. Participation rate was 69% (1651 subjects). Blood pressure measurements consisted of clinic blood pressure (average of three measurements, sphygmomanometry), home blood pressure (average of morning and evening measurements, semiautomatic device) and ambulatory blood pressure (automatic readings at 20 min intervals, Space labs 90207). Clinic blood pressure was obtained both before and after home and ambulatory blood pressures. Data analysis did not include 213 subjects receiving antihypertensive drug treatment and was therefore limited to 1438 participants. Results: In the 1438 subjects, clinic, home and ambulatory blood pressure showed a normal-like distribution, with a taller peak and a narrower base for ambulatory than for home and clinic values. Clinic, home and ambulatory blood pressures were significantly related to each other (P always < 0.001). The means of the two clinic blood pressures obtained on consecutive days were superimposable (127.4 ± 17.0/82.3 ± 9.8 and 128.2 ± 16.5/81.9 ± 9.9 mmHg) and both were markedly higher than home and 24 h average blood pressures (8.2 mmHg), which were similar to one another. The differences between clinic and home or 24 h average blood pressure were similar in both sexes but increased with increasing age and clinic blood pressure values. The influence of clinic blood pressure values on the clinic-ambulatory or clinic–home blood pressure differences was more important than age. Although higher than the 24 h average value, daytime average blood pressure was also lower than clinic blood pressure. Night-time blood pressure was markedly lower than the daytime value in both sexes and at all ages. Conclusion Data from a large and unbiased sample of a general population show that home and 24 h or daytime average blood pressures are much lower than clinic blood pressure. The relatively close correlation between blood pressure values measured with the different methods used has allowed calculation of home and ambulatory blood pressure values corresponding to the accepted upper limit of normality of clinic blood pressure (140/90 mmHg). The upper limit of normality for the population was for both home and ambulatory blood pressures in the range 120–130 and 75–81 mmHg for systolic and diastolic values, respectively, with slight differences depending on sex and age. Taking 140/90 mmHg as the upper normal limit of the population is therefore an error that leads to individuals whose home or ambulatory blood pressures are high being considered as normotensive.

Microbiological pollution and ocular infection in CAD operators: an on-site investigation

A large number of workers are currently employed in tasks involving the use of computer based equipment. Much research has been carried out both on prevalence and incidence of ocular and visual disorders as well as on occupational asthenopia. Less attention has been given to investigating the possibility of a microbiological pollution of Video Display Unit (VDU) workstations and to the consequent possible development of work-related ocular infections. The authors investigated the presence of bacteria and fungi on Computer Assisted Design (CAD) workstations and in the conjunctival sac of the operators.

954 Pushing and pulling assessment: how to deal with inter-operator variability

Introduction Snook and Ciriello has been the leading methods to assess pushing and pulling for roughly 30 years. ISO11228-2 integrated it providing useful add-ons. On duties, workers apply excessive amount of force, for reasons either related to organisational, technical or legal issues. Therefore, inter-operator variability still remains a main issue to be addressed. Methods 378 pushing and pulling test sessions were organised. Forces were measured by means of a computerised dynamometer (200 Hz, 120 Kg scale). 3 health operators (OH) and 2 very trained technicians (T) moved 2 types of hospital beds carrying simulated loads of patients weighting 70, 90 and 110 Kg, on a maximum distance of 300 m. To assess the speed limit (1 m/second) compliance, a 20 m pushing test was repeated multiple times by each tester. The same 20 m test provided individual threshold to compute initial and sustained forces. Initial force was defined as value lying above the threshold, the hysteresis curve and only for coherent data. To compare the speed suggested by the methods with the real speed performed by operators, a 2 months analysis of the patient transportation recorded missions was carried out. Then the accumulated delay-times were estimated with reference to the mean travel time measured at the suggest speed. Results Initial forces resulted 43% (32%–112%) and sustained forces 37% (23%–101%) higher and statistically significant for OH compared to T. Increased speed saves only 25% (12%–56%) of the travel time, due to elevators waiting, doors opening etc. Conclusion Rapidly grooving hospitals often show tortuous paths, where patient transportation on bed is allowed. ISO11228-2 assessment method contribute to solve complex measures, particularly when dealing very long distance pushing and pulling tasks. Initial forces might be calculated by measuring the threshold of the initial force of each operator on a 20 m test. Mean delay time shows risk excess often leading to increased speed behaviours.