Use of clinical biological tests of haemostasis to evaluate topical haemostatics.

INTRODUCTION: In addition to traditional means, topical haemostatics are currently used to avoid haemorrhage during surgery. Although they have been reported to be effective, there is a low level of proof of their clinical efficacy, which is at odds with their levels of use. This study used two methods to better understand their in vitro mechanism of action. METHODS: Two clinical biology assays were used to measure the action of topical haemostatics on primary and secondary haemostasis. Calibrated samples of collagen sponges and polypropylene non-woven gauze were tested. Platelet aggregation was assessed using a multichannel aggregometer. A thrombin generation assay (TGA) was used with a fluorogenic readout. Tissue factor solutions were used to activate coagulation. RESULTS: In terms of primary haemostasis, collagen sponges stimulated platelet aggregation, in particular between 2 and 5 min after incubation with platelet-rich plasma and with no dose effect. In regard to coagulation, the kinetics of thrombin generation was enhanced. Polypropylene non-woven gauze did not exhibit any effect on platelet aggregation, although it did have a weak effect on the kinetics of thrombin generation. CONCLUSION: Collagen is well known to exert a haemostatic effect due to its action on platelet aggregation. By contrast, polypropylene non-woven gauze has not been shown to have any effect on platelet aggregation other than a minor impact on thrombin generation. The results obtained with the devices tested are in agreement with the literature. Platelet aggregation biological assays and TGA measurements appear to be suitable for evaluation of these medical products.

Pediatric parenteral nutrition and hydroperoxide toxicity: Evaluation of the effectiveness of photoprotection medical devices.

Exposure of parenteral nutrition (PN) to light induces hydroperoxide (HPO) formation whose toxicity, especially in pediatrics, is documented. In this context, we evaluated the efficacy of photoprotection medical devices used in our institution to protect PN from degradation after two different exposures to light. A mixed oil lipid emulsion (Smoflipid®) in standard or opaque syringes and a ternary PN mixture bags (Numetah®) with or without opaque overwrap were exposed for at least 420 min to a xenon lamp. Samples of Smoflipid® in standard or opaque syringes were also exposed for 24 h to conditions reproducing those of a neonatal intensive care unit. The use of opaque syringes for Smoflipid® administration or opaque overwraps for Numetah® administration reduced HPO formation by an average of 14% and 40%, respectively, compared to standard conditions after at least 420 min to a xenon lamp. When Smoflipid® samples were administered with standard or opaque syringes and exposed to a phototherapy lamp, the fold-change in the HPO concentration increased, respectively, by 6.3 or 5.4 at 24 h compared with syringes unexposed to phototherapy lamp. Although the observed differences were non-significant, it nonetheless appears prudent to use photoprotection of PN during administration, particularly in patients with immature or compromised antioxidant capacity.