Impact of Biological Point of Care Devices Implementation on the Length of Stay of Patients in Emergency Room

"SUPOC is a monocentric, prospective, open-label, controlled study, randomized into one-week inclusion periods, with 2 types of period: period POC (biological analysis performed as POC in a dedicated emergency room implemented with POC devices) and period control (analysis performed sent and processed in the central laboratory). Randomisation will be carried out by periods of one week (periods of a whole week 24h/24 from Monday 8am to Sunday 8 pm: control period or POC period, with a wash-out period between Sunday 08 pm and Monday 8am before each change of period (in order to limit the patients overlap on 2 periods). The entire medical care including the clinical examination, the prescriptions for additional radiological or biological examinations, requests for specialist advice, as well as the conclusion of the medical file will be left to the sole discretion of the emergency physician in charge of the patient and dictated solely by the reason for consultation and the patient evolution. The comparability of the POC and control periods will be verified, quantitatively (number of patients, average number of paramedical personnel present, the number of medical personnel being fixed) and qualitatively (triage scale applied by the triage nurses into 5 classes).

Despite the randomization of the two periods, the study type is best described as "Observational" because there is no specific intervention or health outcome at the subject level at all. The fact that blood samples are sent in the central laboratory or in the POC platform are both considered as routine medical care. No investigator assigns a specific intervention to the study participants; it is the emergency department itself which changes its internal organization (the destination of the biologic samples) every week. In conclusion, the purpose of the study is to examine the effect of a health provider intervention (POC vs central laboratory use) on a health provider outcome (mean length of stay according to the study period), and there is no health outcomes at the patient level. According to the ICMJE guidelines, this type of study should not be considered as an interventional clinical trial (http://www.icmje.org/about-icmje/faqs/clinical-trials-registration/).

For organizational reasons, 3 laboratory technicians will be recruited and trained specifically for the study. They will be in charge of biological testing during POC periods.

Primary evaluation criteria: length of stay (LOS) of patients consulting the ED, defined by the time between the administrative registration and the medical decision of discharge or hospitalization of the patient. This LOS for each patient meeting the eligibility criteria will be extracted by the hospital's informatic department from the emergency file database. Secondary endpoints: - -the feasibility of an expanded POC menu in the ED will be assessed by the ""converted"" analysis rate, i.e. the number of analyses sent to the central laboratory in the POC period divided by the total number of analyses performed as POC during the period, the rate of unavailability of each POC device for maintenance or breakdown, i.e. the cumulative number of minutes of unavailability for all the POC equipment compared to the total duration of the POC group's periods.

ED's crowding will be evaluated by: the waiting time in each period (time in minutes between emergency registration and first medical contact), the occupancy rate defined by - at time t- the number of patients present / ED's capacity. The capacity of the service is estimated on the basis of the total number of boxes and beds, including short-term hospitalisation units. An overcrowding is set to an occupancy rate> 150%. In practice,it will be extracted by the informatic department from emergency database every day of the study at 12pm, 6pm, 12am and 8am.

The time to results in each period and by biological parameter will be extracted from the laboratory software.

The health-economic impact of the expanded implementation of POC will be assessed by the average total cost of an ED's visit in each period. The costs and consequences of the implementation of the POC will be estimated in a comparative way in the two periods, taking into account on the one hand the point of view of the establishment and on the other hand that of the healthcare system. The investigators will estimate an average cost per patient and per emergency room visit.

The satisfaction of staff and patients will be evaluated by an anonymous questionnaire including satisfaction scales on the overall quality of care in emergency department and on the results of biological analyses, among patients (on a sample) and all staff (emergency physicians and biologists, ED's nurses).

Sample size calculation: This is a one-week randomized cluster study. A preliminary study of the first 6 months of 2016, using ED's software to extract data from emergency department visits, estimated an average cluster size of 1100 patients, with a size variation coefficient of 0.2, as well as a standard deviation of 2 hours and 20 minutes.

Assuming an average reduction of 20 minutes of the main judgement criterion, and an intraclass correlation coefficient of 0.01, with a bilateral alpha equal to 5%, study will have to include 9 clusters in each period to obtain a power of 80% - 18 weeks total duration of inclusion.

For a monocentric study including all patients consulting in an adult emergency department with a total of 60,000 visits per year, each month will allow the inclusion of at least 4,400 patients.