[Perioperative management based on kinetics of bleeding during total primary arthroplasty]. / Cinétique du saignement en chirurgie orthopédique majeure : implications pour la prise en charge périopératoire.

INTRODUCTION: Management of the perioperative hemorrhagic risk is of major interest in patients undergoing total arthroplasty of the lower limb. Anemia in the postoperative period of that increasingly performed surgery carries its own morbidity and mortality. Better anticipation of its occurrence could be done with a refined knowledge of bleeding kinetics. PATIENTS AND METHODS: We conducted a retrospective study in a single centre on 451 consecutive patients undergoing elective unilateral primary total hip or knee arthroplasty for osteoarthritis. Volume of total blood loss according to Mercuriali's formula and variations of haemoglobin levels were calculated between day 0 (D0) and postoperative day 8 (D8), and during subdivided periods between D0-D1, D1-D3 and D3-D8. Frequency and volume of autologous and homologous blood transfusions were also analyzed. Comparisons were done taking into account the use of intraoperative tranexemic acid (TA). RESULTS: Seventy to 75% of blood loss occurred between D0 and D1. Bleeding occurred mostly between the end of surgery and morning of D1, and tended to stop at D3. TA significantly reduced blood loss in the first 3days, mostly after knee prosthesis surgery. However, the bleeding kinetics were the same with or without TA. CONCLUSION: Loss of haemoglobin occurred mostly in the early postoperative period. To avoid transfusion delays, haemoglobin levels should be monitored regularly until the third postoperative day after total arthroplasty, especially when D1 haemoglobin is close to the transfusion threshold. Furthermore, our results support the routine use of TA.

Adherence to a new oral anticoagulant treatment prescription: dabigatran etexilate.

The recent development of new oral anticoagulants, of which dabigatran etexilate is currently at the most advanced stage of development, is the greatest advance in the provision of convenient anticoagulation therapy for many years. A new oral anticoagulation treatment, dabigatran etexilate, is already on the market in Europe. The main interest probably will be to improve the prescription and the adherence to an effective thromboprophylaxis in medical conditions such as atrial fibrillation without bleeding side effects, without the need for monitoring coagulation, and without drug and food interactions such as vitamin K anticoagulant (VKA) treatment. Dabigatran is particularly interesting for extended thromboprophylaxis after major orthopedic surgery in order to avoid daily injection for a month. However, oral long-term treatments such as VKA are not systematically associated with a higher compliance level than injected treatments such as low-molecular-weight heparins. Indeed, adherence to an oral treatment, instead of the usual daily injection in major orthopedic surgery, is complex, and based not only on the frequency of dosing but also on patient motivation, understanding, and socio-economic status. New oral anticoagulants may be useful in this way but education and detection of risk factors of nonadherence to treatment are still essential.

[Dabigatran (Pradaxa): efficacy and safety]. / Dabigatran (Pradaxa): efficacité et tolérance.

There is considerable interest in developing new, orally available anticoagulants for the prevention and treatment of thrombotic disorders. In Europe, the low-molecular-weight heparins (LMWHs) are more commonly prescribed for thrombosis prevention, but require parenteral administration, platelets monitoring twice a week during the first month. Furthermore, LMWH are not synthetic. All of these characteristics can be an obstacle to optimal patient care, particularly when outpatient dosing is required after early discharge. New oral anticoagulants that require no monitoring and can be administered in a fixed dose without drug-drug and drug-food interactions would clearly offer practical advantages if shown to be safe and effective. dabigatran étexilate, a new oral, direct thrombin inhibitor, is the prodrug of the active compound dabigatran, which binds reversibly to thrombin with high affinity and specificity. This agent has a rapid onset of action, a predictable and reproducible that permit once-daily dosing. To date, more than 8,000 patients have been studied in clinical trials, and more than 38,000 individuals are enrolled in ongoing trials. Three major prospective, randomized, double-blind non-inferiority trials have compared the efficacy and safety of dabigatran étexilate (150 mg or 220 mg once-daily) starting postoperatively, with subcutaneous enoxaparin, in patients undergoing hip (RE-NOVATE trial) or knee arthroplasty (RE-MOBILIZE and RE-MODEL). Based on these trial results, dabigatran étexilate is approved for use in the European Union and Canada for primary prevention of VTE in patients having undergone elective total hip and knee arthroplasty. Pradaxa is now on the market in France since December 2008.

[Blood conservation approaches in orthopedic surgery]. / Epargne transfusionnelle en chirurgie orthopédique.

In addition to more restrictive "transfusion triggers", presently available allogeneic blood conservation strategies in surgery include preoperative increase in red blood cells (RBC) mass, techniques or pharmaceutical agents that reduce blood loss, and perioperative blood salvage. Because of very important risk reduction in allogeneic blood, benefit/risk of preautologous blood donation (PAD) is quite questionable at this moment. Indeed, at this moment in France, we focus to avoid any transfusion (allogeneic and autologous blood). Therefore the most important techniques used are pharmacological: erythropoietin before surgery with a number of injections related to baseline Hb, and tranexamic acid during and after surgery. Cell saving is used only if bleeding is enough important like arthroplasty revisions. All blood conservation techniques carry their own efficiency limits, constraints and risks that, in addition to institutional considerations and individual patient characteristics are determinant to settle a blood conservation strategy. The choice of a technique should take into account (a) the delay before surgery, (b) the anticipated blood loss for the procedure that varies among institutions, (c) the tolerable blood loss without transfusion for the patient, and (d) the efficacy of the blood conservation technique in the given setting. Nevertheless, at this moment in France, it is quite important to notice that the risk of delay or lack of transfusion induces much more deaths that the transfusion itself during or after anesthesia [Anesthesiology 105, 1087-97].

[Rivaroxaban (Xarelto): efficacy and safety]. / Rivaroxaban (Xarelto): efficacité et tolérance.

The oral direct Xa inhibitor rivaroxaban (Xarelto) shows great promise for prevention of venous thromboembolic events after major elective orthopedic surgery. Its consistent and predictable pharmacokinetics and pharmacodynamics across a wide range of patient populations allow administration with fixed dosing and with no coagulation monitoring. In 4 orthopaedic surgery clinical trials (12,700 patients), 10mg postoperative (6-10 hours after the end of surgery) dose, once daily, of oral rivaroxaban, achieved superior efficacy and similar safety to enoxaparin, whatever the dose of enoxaparin. Indeed, 40 mg once a day in Europe and 30 mg bid in US of enoxaparin were compared to the same dose of 10mg once daily of rivaroxaban. Furthermore, there is no difference according to liver enzymes elevation and cardio-vascular adverse events. Although the risk of spinal haematoma after neuraxial anaesthesia is rare, it is increased by concomitant use of anticoagulants. In orthopedic surgery trials with rivaroxaban to date, complications such as spinal haematoma have not been reported. The pharmacokinetic profile of rivaroxaban suggests that concurrent use with neuraxial anaesthesia should require no further precautions than currently necessary with low-molecular-weight heparin.

[Refractory hypoxemia treated early by HFO in a severe traumatic brain injury patient]. / Hypoxémie réfractaire traitée précocement par HFO chez un patient traumatisé crânien grave.

A 23-year-old man without previous medical history, was transferred to our surgical intensive care unit for management of a traumatic brain injury (Glasgow Coma Score of 3 on admission). He rapidly presented a refractory hypoxaemia essentially due to posterior alveolar collapse. Severe hypoxaemia and hypercarboxaemia didn't respond to conventional ventilation and complicated the management of the brain injury and the control of intracranial pressure. The introduction of high-frequency oscillatory ventilation permitted a respiratory improvement in 48 hours and a good neurological outcome.

Quantitative determination of C-polysaccharide in Streptococcus pneumoniae capsular polysaccharides by use of high-performance anion-exchange chromatography with pulsed amperometric detection.

Capsular polysaccharides of Streptococcus pneumoniae are used to formulate polyvalent pneumococcal vaccines. A sensitive method, using high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD), has been developed to quantify the contamination of pneumococcal capsular polysaccharides (PnPs) with the C-polysaccharide (C-Ps). As this polysaccharide is highly immunogenic, and since anti C-Ps antibodies are not protective, the need to monitor and reduce its level is of uppermost importance. The method is based on the quantification by HPAEC-PAD of ribitol, which is released by a two-step hydrolysis of the PnPs using aqueous hydrofluoric acid (HF) followed by trifluoroacetic acid hydrolysis (TFA). This simple method has been shown to provide both qualitative and quantitative information about the purity of polysaccharide preparations.

Remote access to electronic library services through a campus network.

The Health Science Library at University of Tennessee (UT), Memphis has taken advantage of a campuswide network for the purpose of providing enhanced access to library services. With a terminal or microcomputer, members of the UT Memphis community can use an electronic menu system to complete photocopy, interlibrary loan, and computer literature search request forms; leave messages or sign up for library workshops; use electronic mail to receive citations and abstracts from computer literature searches; use an electronic bulletin board to scan the library's new acquisitions lists, library hours, services, and policies; and use bibliographic retrieval software to search the library's locally mounted databases. Remote access to library services and electronic resources, which is available twenty-four hours a day, could potentially save users time and the institution money. Remote access, however, is intended to supplement, not to supplant or discourage, in-house library use.

Application of a general database manager in a clinical medical librarian program.

The morning report reference file was automated at the Stollerman Library because the manual system was time-intensive to maintain and cumbersome to search. A general database management system (DBMS) was chosen so that it could be used in the future for other data management functions in the library. DBMS features that should be examined before use with a bibliographic application include size limitations, data entry forms, data types, search options, index files, sort options, report generation, query and programming languages, command and/or menu files, file interaction, interface with other software, and documentation. Desired requirements for this application are discussed. It is noted that a general database manager probably will not meet all of the desired requirements. For some bibliographic applications, software specifically designed for bibliographic information management and retrieval should be used. A database for the purposes of searching the morning report reference file and producing a weekly reference list and a yearly index was developed using CONDOR 3. The structure of the database is described, and examples of the reports are given. The system has been in operation since December 1984 and has been well-received by staff and patrons.

Natural transmission of Dirofilaria immitis by Aedes aegypti.

The Liverpool strain of the mosquito Aedes aegypti was infected with microfilariae of the canine heartworm, Dirofilaria immitis, and was used to transmit heartworm larvae to three dogs. Methods of confirming heartworm infection in these dogs included the modified Knott's test, a commercial enzyme-linked-immunosorbent assay (ELISA), an indirect fluorescent antibody (IFA) test, and post-mortem examination.