Objectives: Estimating blood loss is an important factor in several surgical procedures. The accuracy of blood loss measurements in situations where blood is mixed with saliva and saline is however uncertain. The purpose of this laboratory study was to ascertain if blood loss measurements in mixtures of blood, saline, and saliva are reliable and could be applicable in a clinical setting.

Material and Methods: Venous blood and resting saliva were collected from six volunteers. Saliva, saline, and combinations thereof were mixed with blood to obtain different concentrations. A portable spectrophotometer was first used to measure the haemoglobin concentration in undiluted venous blood followed by measurements of the haemoglobin concentration after each dilution. To examine the strength of linear relationships, linear regression and Pearson correlations were used.

Results: The measurements of haemoglobin concentrations in mixtures of blood, saline, and saliva were proven to be accurate for haemoglobin measurements > 0.3 g/dl (correlation = 0.986 to 1). For haemoglobin measurements < 0.3 g/dl, a small increase in haemoglobin values were reported, which was directly associated to the saliva concentration in the solution (correlation = 0.983 to 1). This interference of saliva was significantly eliminated by diluting the samples with saline, mimicking the clinical situation.

Conclusions: The results suggest that a portable spectrophotometer can be used clinically to preoperatively measure the haemoglobin value of a venous blood sample and postoperatively measure the haemoglobin value of the collected liquids, including shed blood, thereby achieving a highly accurate method of measuring blood loss during oral and maxillofacial surgery.

OBJECTIVE: The recommendations for the management of direct oral anticoagulants (DOACs) in oral surgery are inconsistent. The present review evaluated whether DOACs increase the risk of bleeding during oral surgery and postoperative complications.

STUDY DESIGN: The patients undergoing oral surgery and receiving a DOAC were compared with the patients receiving a DOAC different from the exposure, a vitamin K antagonist (VKA), or no anticoagulant. Three electronic databases were searched for eligible clinical trials and systematic reviews. The risk of bias was assessed, data were extracted, a meta-analysis was done, and the Grading of Recommendations, Assessment, Development and Evaluations certainty-of-evidence ratings were determined.

RESULTS: Three clinical trials comparing patients receiving DOAC medication with patients on a VKA were eligible. A meta-analysis of bleeding 7 days postoperatively detected no significant differences between patients continuing DOAC or VKA medication during and after surgery. All of the point estimates favored uninterrupted DOAC over VKA therapy. Tranexamic acid was topically administered to some patients.

CONCLUSIONS: Based on an interpreted trend among 3 studies with mixed patient populations, the risk of bleeding during the first 7 postoperative days may be lower for patients on uninterrupted DOAC than VKA therapy (⨁⨁⭘⭘), but the effect size of the risk is unclear. 80 of 274 included patients experienced postoperative bleeding.

BACKGROUND: No consistent approach to the management of direct oral anticoagulants (DOACs) during and after oral surgery has been established. Thus, DOACs may be unnecessarily discontinued, raising the potential risk of life-threatening thromboembolism. To address the inconsistency in this approach, our study assessed the risk of bleeding and other complications in patients who continue to use DOACs during and after simple and surgical tooth extractions.

METHODS: Between May 2016 and December 2023, this prospective study recruited patients aged 18 years or older who were receiving a DOAC or warfarin and were in need of simple or surgical extractions of one or more teeth. Local haemostatic agents were being used to control bleeding. Patients were instructed to manage minor postoperative bleeding at home by biting down on gauze soaked in tranexamic acid for at least 30 min. After surgery, all patients were followed for 7 days. The chi-squared test compared dichotomous variables; the two-sample t-test, continuous variables; logistic regressions, dichotomous outcomes; and linear regressions, continuous outcomes.

RESULTS: In all, 354 teeth were extracted from 160 patients receiving DOACs and 56 patients receiving warfarin. The incidence of any type of postoperative bleeding was 27% in patients receiving DOACs and 37% in those receiving warfarin (OR 0.66, 95% CI: 0.28-1.57; p = 0.35). Most patients were able to manage any bleeding at home themselves. Clinically relevant bleeding necessitating prompt evaluation or a secondary surgical intervention by a dentist or healthcare professional occurred in 3% of patients receiving DOACs and 11% of patients receiving warfarin (OR 0.30, 95% CI: 0.08-1.06; p = 0.06). No reports of major bleeding requiring hospitalization or blood transfusion were found. Perioperative bleeding volume was comparable between the two groups.

CONCLUSIONS: Patients receiving DOACs without interruption during surgery may have a lower risk of bleeding than those on warfarin. Patients may safely continue to use DOACs during and after simple and surgical extractions. This eliminates the potentially higher risk of serious thromboembolic events that are associated with a pause in anticoagulant therapy.

CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov (ID: NCT04662515). Retrospectively registered 4 December 2020.