Influence of hyperbaric oxygen therapy on thrombus formation ability in humans.

Background: Hyperbaric oxygen (HBO2) therapy was introduced nearly 300 years ago. However, its effect on thrombus formation is unclear. This may be because platelet and coagulation functions are unstable, yielding variable results; hence, accurate measurement is difficult. Our study aimed to analyze changes in thrombus formation before and after HBO2 therapy by using a total thrombus formation analysis system (TTAS). Methods: Six patients were prescribed HBO2 therapy for skin and soft tissue ulcers, and necrotic fasciitis. Blood samples were collected immediately before and after treatment. Then samples were put into a reservoir that connected to AR-chip to assess changes in the thrombus formation ability of both platelets and coagulation factors. We examined the differences in the thrombus formation ability using T-TAS. Time until the onset of white thrombus formation (T10) and complete occlusion of the capillary (T80) were analyzed by a two-way repeated measure analysis of variance (ANOVA). Results: The duration to pressure increase of samples after HBO2 therapy was longer than the duration before HBO2 therapy (p<0.05). This suggests decreased clot adhesiveness to the inner surface of the simulated blood vessel and reduced clot formation ability. Conclusions: The results for T10 and T80 suggest that HBO2 therapy reduced thrombus formation ability in the enrolled patients. We believe that T-TAS is a promising method to predict the efficacy of HBO2 therapy.

Influence of high-dose antithrombin on platelet function and blood coagulation.

AIM: In healthy adults, there are sufficient amounts of antithrombin in the blood to regulate thrombin. However, the effects of high concentrations of antithrombin on dose-dependent anticoagulation and platelet function have not been reported. In this study, we assessed platelet function and blood coagulation following high-dose antithrombin supplementation in vitro. METHODS: Blood samples were collected from 10 healthy volunteers, and samples with different antithrombin concentrations were prepared by adding an antithrombin agent (Neuart). Blood coagulation was assessed by the Thrombus-Formation Analysis System (T-TAS) and Rotational Thromboelastometry (ROTEM) using whole blood samples. RESULTS: The data obtained by the platelet chip, exclusively representing platelet function, revealed that the onset of thrombus formation was significantly delayed in a dose-dependent manner (100%-200%, P = 0.021; 100%-500%, P = 0.011; 200%-500%, P = 0.047). In measurements using the atheroma chip, which enables assessment of blood coagulation, the thrombus formation ability was found to be reduced (100%-200%, P = 0.022; 100%-500%, P = 0.05). In the ROTEM measurements, clotting time was prolonged in a dose-dependent manner (100%-200%: P = 0.203, 200%-500%: P = 0.005, 500%-1000%: P = 0.022), except when comparing with 100% and 200%. Although antithrombin is reportedly saturated in healthy blood, its anticoagulant ability appears to be enhanced depending on its concentration. Furthermore, data obtained from the platelet chip showed that antithrombin might reduce platelet function. CONCLUSIONS: Antithrombin suppressed platelet function and blood coagulation in a dose-dependent manner.

Development of a delirium predictive model for adult trauma patients in an emergency and critical care center: a retrospective study.

BACKGROUND: Delirium has been shown to prolong the length of intensive care unit stay, hospitalization, and duration of ventilatory control, in addition to increasing the use of sedatives and increasing the medical costs. Although there have been a number of reports referring to risk factors for the development of delirium, no model has been developed to predict delirium in trauma patients at the time of admission. This study aimed to create a scoring system that predicts delirium in trauma patients. METHODS: In this single-center, retrospective, observational study, trauma patients aged 18 years and older requiring hospitalization more than 48 hours were included and divided into the development and validation cohorts. Univariate analysis was performed in the development cohort to identify factors significantly associated with prediction of delirium. The final scoring system for predicting delirium was developed using multivariate analysis and internal validation was performed. RESULTS: Of the 308 patients in the development cohort, 91 developed delirium. Clinical Frailty Score, fibrin/fibrinogen degradation products, low body mass index, lactate level, and Glasgow Coma Scale score were independently associated with the development of delirium. We developed a scoring system using these factors and calculated the delirium predictive score, which had an area under the curve of 0.85. In the validation cohort, 46 of 206 patients developed delirium. The area under the curve for the validation cohort was 0.86, and the calibration plot analysis revealed the scoring system was well calibrated in the validation cohort. DISCUSSION: This scoring system for predicting delirium in trauma patients consists of only five risk factors. Delirium prediction at the time of admission may be useful in clinical practice. LEVEL OF EVIDENCE: Prognostic and epidemiological, level III.