Making safer preoperative arrangements for patients using vitamin K antagonists

Use of vitamin K antagonists creates a risk for patient health and safety. The Dutch framework "Nationwide Standard Integrated Care of Anticoagulation" propagates a shared plan and responsibility by surgeon and anesthesiologist together in the preoperative setting. In our institution, this framework had not been implemented. Therefore, a quality-improvement project was started at the Anesthesia Department to improve perioperative safety. After exploration of barriers, multiple interventions were carried out to encourage co-workers at the preoperative screening department to take shared responsibility: distribution of prints, adjustments in electronic patient records, introduction of a protocol and education sessions. Efficacy was measured retrospectively performing a before-after study collecting perioperative data of patients using vitamin K antagonists. The primary outcome measure was the percentage of predefined safe preoperative plans. Secondary outcome measures were (1) incidence of postoperative bleeding and thrombo-embolic events within the first 24 hours after intervention and (2) necessity to preoperative correction of anticoagulation. Before intervention 72 (29%) safe, 93 (38%) partially unsafe and 83 (33%) unsafe arrangements were made. After the intervention these numbers were 105 (80%), 23 (17%) en 4 (3%), respectively: a significant 51% increase in safe preoperative plans (P<0.001). We observed no significant difference (P=0.369) regarding bleeding and thrombo-embolic events: pre-intervention 12 (5%) cases of postoperative bleeding were documented, vs. 6 (5%) post intervention and the number of thrombo-embolic events was 5 (2%) vs. 0. Also, no significant differences concerning preoperative correction of anticoagulation were observed: 11 (4%) vs. 8 (6%) (P=0.489). This quality improvement project demonstrates a major improvement in safer preoperative arrangements in our institution regarding vitamin K antagonists, using the described interventions. A significant effect on bleeding or thrombo-embolic events or necessity to correction of anticoagulation could not be demonstrated.