Comprehensive preoperative evaluation of platelet function in total knee arthroplasty patients taking diclofenac

The effectiveness of low-dose desmopressin in improving hypothermia-induced impairment of primary haemostasis under influence of aspirin - a randomized controlled trial

BACKGROUND

Mild hypothermia (34-35 °C) increases perioperative blood loss. Our previous studies showed that desmopressin could have in vitro beneficial effects on hypothermia-induced primary haemostasis impairment. In this study, we investigate the in vitro effects of desmopressin on hypothermia-induced primary haemostasis impairment under the influence of aspirin in healthy volunteers.

METHODS

Sixty healthy volunteers were randomly allocated to taking aspirin 100 mg or placebo for three days. On the sixth day blood samples were taken before and after the injection of desmopressin (1.5 microgram or 5 microgram) or normal saline subcutaneously. Measurements including Platelet Function Analyzer (PFA-100®) closure times, plasma von Willebrand Factor antigen, haemoglobin and platelet levels were made at 32 °C and 37 °C respectively.

RESULTS

Collagen/epinephrine closure time (EPICT) was significantly prolonged by 21.13 % (95 %CI 2.34-39.74 %, p = 0.021) in aspirin group at 37 °C. While hypothermia alone prolonged both collagen/adenosine diphosphate (ADPCT) and EPICT by 17.63 % (95 %CI 13.5-20.85 %, p < 0.001) and 8.0 % (95 %CI 6.38-10.04 %, p = 0.024) respectively, addition of aspirin only further prolonged EPICT by 19.9 % (95 %CI 3.32-36.49 %, p = 0.013). In aspirin group, desmopressin 1.5 microgram and 5 microgram significantly reduced ADPCT to below baseline levels at 37 °C (p = 0.025 and <0.001 respectively), whereas reduction in EPICT was seen with desmopressin 5 microgram (p =0.008). The effect was less pronounced at 32 °C, with a significant reduction in EPICT obtained with a dosage of 5 microgram only (p = 0.011).

CONCLUSION

It was shown that aspirin could further potentiate the hypothermia-induced closure time prolongations. Low dose desmopressin (1.5 microgram) reduced PFA-100® closure times towards baseline. A higher dosage (5 microgram) further reduced the closure times below baseline. Therefore low dose desmopressin (1.5 microgram) might have the potential to correct hypothermia-induced primary haemostasis impairment under the influence of aspirin during the perioperative period.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01382134.

COX-2 inhibition: what we learned--a controversial update on safety data

IMPORTANCE

Cyclooxygenase type 2 (COX-2)-selective nonsteroidal anti-inflammatory drugs (NSAIDs) (c2sNSAIDs) have been scrutinized relative to the less costly nonselective NSAIDs (nsNSAIDs). The conclusions reached were not always consistent with the data, and best treatment choices for patients were not always recommended.

OBJECTIVE

The data that were used to criticize the c2sNSAIDs are reexamined in a controversial light, demonstrating that the presence of reverse bias was often, but not always, present.

EVIDENCE REVIEW

A review of both Pubmed and news media articles relating to nsNSAIDs and c2sNSAIDs was conducted. References were selected on the basis of relevance to the controversies.

FINDINGS

The initial claims for the c2sNSAIDs of reduced gastrointestinal (GI) injury and preservation of platelet function were soon dwarfed by concerns regarding increased cardiovascular (CV) risk with publication of the Vioxx Gastrointestinal Outcomes Research trial for rofecoxib. Initial prothrombotic theories had a poor basis for explaining these concerns and have since largely been replaced with more credible explanations, including blood pressure elevations known to occur with all NSAIDs. Between data suggesting increased CV risk and under political pressure and public outcry, rofecoxib was withdrawn from the market in 2004. Soon, all c2sNSAIDs were under scrutiny. The Food and Drug Administration has since grouped all NSAIDs, whether c2sNSAID or nsNSAID, into one class with similar warnings regarding skin, CV, renal, and GI side effects.

CONCLUSIONS AND RELEVANCE

The entire "COX-2 debacle" is reminiscent of past events with NSAIDs. Amid this public, media, and political hysteria, it is not clear if we will see any more NSAIDs (selective or otherwise) approved in the near future.