ABSTRACT
BACKGROUND: Haemorrhage is associated with haemostatic dysfunction. Previous studies have focused on coagulation factors, but platelet function plays an equally important role. The time course of alterations in platelet function in relation to injurious stimuli is not known. AIM: To evaluate short-term, intra-operative changes in platelet function, by whole blood impedance aggregometry in patients undergoing hip arthroplasty. The primary outcome was platelet aggregation in response to adenosine diphosphate (ADP) stimulation. We also evaluated other agonists, and the feasibility of conducting platelet aggregometry measurement in the operating theatre. METHODS: Patients undergoing primary cemented hip arthroplasty had six peri-operative arterial blood samples analysed at pre-set stages of the operation, using the Multiplate Impedance Aggregometer. Four agonists were used: ADP, TRAP, Collagen and Arachidonic Acid. RESULTS: There was a statistically significant change (p<0.05, ANOVA) in platelet response to ADP over the course of the operations. The trend demonstrated an initial decrease in responsiveness, followed by increased platelet responsiveness in the later stages. Other agonists (TRAP, COL, ASPItest) demonstrated a similar pattern of changes. Of 360 tests conducted, 12 (3.3%) had to be re-run due to poor intra-assay variability. Satisfactory values were obtained on the second attempt in all 12 samples. CONCLUSION: Platelet function, as measured by impedance aggregometry, changes in response to a surgical stimulus involving blood loss. The clinical significance of these changes, and the potential of manipulating them for therapeutic purposes, remains to be elucidated.
Subject(s)
Hemorrhage/blood , Platelet Function Tests/methods , Adenosine Diphosphate/chemistry , Aged , Anticoagulants/therapeutic use , Arachidonic Acid/chemistry , Arthroplasty, Replacement, Hip , Blood Coagulation Tests , Blood Platelets/immunology , Collagen/chemistry , Female , Hemorrhage/drug therapy , Humans , Intraoperative Period , Male , Middle Aged , Peptide Fragments/chemistry , Platelet Activation/drug effects , Platelet Aggregation , Platelet Aggregation Inhibitors/chemistry , Prospective StudiesABSTRACT
A previous audit conducted in the West of Scotland (WoS) suggested that anatomical factors accounted for a substantial proportion of invaded surgical margins after resection of an oral or oropharyngeal squamous cell carcinoma (SCC). Since then a number of technical improvements have taken place, the most important of which has been advanced digital imaging that has enabled better surgical planning. In this study we compare the incidence of involved surgical margins in a recent group with those found in the earlier audit. The earlier (WoS) group comprised a consecutive series of patient operated on for a primary SCC of the oral cavity or oropharynx between November 1999 and November 2001 (n=296). The later series comprised 178 patients operated on for oral or oropharyngeal SCC at the Southern General Hospital (SGH), Glasgow, between 2006 and 2009. A total of 245 patients in the WoS cohort had information available on the invasion of the margins of whom 68 (28%) had an invaded margin. Of 177 patients in the SGH group, 9 (5%) had an invaded margin (p=0.001). An anatomical approach to the resection of oral and oropharyngeal SCC is appropriate, as it results in a rate of invaded margins of less than 10% irrespective of size and site of the primary lesion.
