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We begin with a detailed study of a delayed SI model of disease transmission with immigration into both classes. The incidence function allows for a nonlinear dependence on the infected population, including mass action and saturating incidence as special cases. Due to the immigration of infectives, there is no disease-free equilibrium and hence no basic reproduction number. We show there is a unique endemic equilibrium and that this equilibrium is globally asymptotically stable for all parameter values. The results include vector-style delay and latency-style delay. Next, we show that previous global stability results for an SEI model and an SVI model that include immigration of infectives and non-linear incidence but not delay can be extended to systems with vector-style delay and latency-style delay. [ABSTRACT FROM AUTHOR]

Background: An important cause of coagulopathy in cardiac surgery is impaired thrombin generation. While plasma is often used to correct this element of the coagulopathy, studies in vitro suggest that prothrombin complex concentrates (PCCs) might be more effective. Comparative data, however, are scant.Methods: We compared the outcomes of those who received only plasma with those who received PCCs (with or without plasma) for management of coagulopathy in patients who underwent cardiac surgery with cardiopulmonary bypass at a single institution from 2012 to 2016. Propensity score matching was used to obtain between-group balance. Primary outcome was avoidance of perioperative red cell transfusions. Other outcomes were incidence of massive transfusion (more than nine red cell units), refractory bleeding (requiring factor VIIa), and adverse events.Results: Of 6362 patients, 1151 (18.2%) received plasma without any PCCs, and 204 (3.2%) received PCCs, either with (n=125) or without plasma (n=79). Overall, patient risk-profile was higher in the PCCs group. In a well-balanced propensity score match that included 117 patients per group, the odds ratio (OR) for red cell avoidance was 2.4-fold [95% confidence interval (CI) 1.2-4.8] higher in the PCCs group. Massive transfusion (OR 0.58; 95% CI 0.33-1.0) and refractory bleeding (OR 0.49; 95% CI 0.24-1.03) incidences were almost significantly lower in the PCCs group. The adverse event profiles were similar.Conclusions: Our exploratory study suggests that the use of PCCs as part of a multifaceted coagulation management strategy may have blood-sparing effects. Their incorporation into clinical practice, however, must await determination of their risk-benefit profile via multicentre randomised trials. [ABSTRACT FROM AUTHOR]