Effectiveness and safety of a management protocol to correct over-anticoagulation with oral vitamin K: a retrospective study of 1,043 cases.

BACKGROUND: Timely reversal of excessive anticoagulation is important in preventing bleeding complications. The use of vitamin K in correcting over-anticoagulation is widely accepted to be superior to discontinuation of therapy but its effectiveness and safety in large scale cohort studies has not been assessed. METHODS: According to our protocol, 2 mg of oral vitamin K in addition to omitting the day's dose of warfarin, were administered to all patients presenting INR levels >or=5.0 and below 10.0; the INR values were checked 20 h after vitamin K administration. The rate of decay of INR, bleeding and thromboembolic complications at presentation and the following 30 days, as well as resistance to warfarin were assessed. RESULTS: Of the 1,611 events, 1,043 (878 patients) met the selection criteria. The median (interquartile range) INR was 6.64 (6.12-7.52) at presentation (day zero) and fell to a median (interquartile range) INR of 2.72 (2.18-3.52, P < 0.0001) after the vitamin K administration (day one) and 90.6% of the INRs were below 4.5. In 98 (9.4%) instances the INR values did not fall below the safe limit of 4.5 and in 173 (17%) instances the INR values were overcorrected to below 2.0. Median INR value on day zero in these two groups was higher (7.3 vs. 6.6, P < 0.0001) and lower (6.5 vs. 6.7, P = 0.049) than that of the remaining cases, respectively. Overcorrection occurred more frequently in women (P = 0.0002). Female gender was an independent factor associated with INR overcorrection (P = 0.001; OR = 1.7, 95% CI 1.3-2.3). The INRs on day one were inside, above and below the therapeutic range in 44%, 36% and 20% respectively. Warfarin resistance was observed in six cases (0.6%). Major bleeding was reported in one case (1.1 per 100 patient-years), minor bleeding in 14 cases (16.1 per 100 patient-years) and thromboembolic events in six high risk patients (6.9 per 100 patient-years) during the one month period following vitamin K administration. CONCLUSIONS: This adopted protocol for the reversal of excessive anticoagulation in asymptomatic or minor symptom presenting patients is easily applied, effective in lowering the INR and preventing complications. Its use in high risk thromboembolic patients warrants caution.

Motorcycle riders' perception of helmet use: complaints and dissatisfaction.

In accidents which involve two-wheeled vehicles the helmet plays a life-saving role, but very little is known about the motorcycle rider's perception of the helmet. We evaluated the relationships between having been involved in an accident and dissatisfaction with the helmet, and between the perception of motorcycle riders and the objective features of the helmet. This was a case-control study: riders of motorized two-wheelers who had been involved in accidents (accident cases) were compared against a similarly interviewed sample of riders that had not been in accidents (control cases). Information about the driver, the vehicle and the helmet was collected in all interviews. To evaluate the relationships, logistic regressions were carried out. The majority of drivers were dissatisfied with their helmets, but no evidence was found to link this dissatisfaction with having been involved in an accident. The two most common complaints related to noisiness, followed by the helmet visor. Complaints did not seem to be statistically associated with physical features of the helmet.