Preventing thromboembolism after surgery using a patient and procedure specific approach to thromboembolism risk assessment and prevention, in cancer surgery patients.

The multi-staged Surgical Thrombo-Embolism Prevention quality improvement program (STEP-QIP) established a protocol that stratified patients into low, intermediate, and high risk profiles according to surgical procedure and patient baseline medical risk. Expert-endorsed risk-specific thromboprophylaxis strategies were then applied. The Surgical Thrombo-Embolism Prevention protocol (STEP-P) consisted of a risk-assessment tool and decision-making algorithm, based on evidence-based risk-category specific recommendations for thromboprophylaxis (TP) – including type (mechanical-TP, pharmacological-TP), time of initiation, and duration of application of interventions. The risk assessment model defined the risk profile for the specific patient interaction. The initial step assessed the procedural thromboembolism (TE) risk to determine the surgical risk profile - low, intermediate or high – which was then combined with the patient’s medical TE risk profile to generate an overall TE risk profile. The surgical risk profile considered the duration of surgery and the extent of tissue injury. Surgery under 45 minutes was considered as low TE risk and included endoscopic procedures and excisions of cutaneous lesions. Non-major surgery and major surgery equal or greater than 45 minutes was classified as intermediate and high TE risk, respectively. Intermediate TE surgeries included procedures on connective tissue, non-complex orthopaedic, head and neck (e.g. parotidectomy, thyroidectomy), breast, non-complex abdominal (e.g. appendectomy), laparoscopic/robotic partial nephrectomy or simple prostatectomy that did not include pelvic lymph node dissection. High TE surgery included major intracavity (thoracic/abdominal/pelvic), sarcoma, pelvic lymph node dissection, obstetric, microvascular free flap reconstruction, vascular, complex orthopaedic, cardiothoracic/oesophagectomy and cranial/spinal procedures. The medical risk was simplified to a TE risk score based on 13 validated risk factors. Each risk factor was given a weighted risk score from 0.5 to 2 according to published odds ratio. A score of 2 or more escalated the surgical risk profile from low to intermediate or from intermediate to high. Factors that received a TE risk score of 0.5 included: age greater than 60, body mass index (BMI) between 35 and 40 Kg/m^2, heart failure or recent acute myocardial infarction (within 6 weeks), oestrogen hormone therapy, platelet count > 350 x 10^9/L, and Fibrinogen > 4 g/L. Factors that received a TE risk score of 1 included active cancer (excludes localised non-melanomatous skin lesions), severe obesity BMI > 40 Kg/m^2, prolonged (> 4 days) or severe immobility prior to surgery, and the oral contraceptive pill. Factors that received a TE risk score of 2 included prior Thromboembolism, known inherited thrombophilia, and pregnancy or puerperium. The surgical and medical risk profiles together determined the overall TE risk classification as low, intermediate or high-risk profiles. Intermediate and high-risk profiles received sequential compression devices (SCDs) (Covidien - Kendal SCD express sleeves, thigh length) for the duration of the surgery (intraoperative SCD). Covidien Kendal SCDs were the compression device standard at our institution and were used during this study. Intermediate risk profiles also received Thromboembolic Deterrent Stockings (TEDs) for at least 7 days. High risk patients received TEDS for the duration of their inpatient stay only. Low risk and intermediate risk patient that required admission after their surgery received P-TP for the duration of their inpatient stay only. For high risk patients P-TP was added, which was started intraoperatively or within six hours postoperatively. P-TP was continued for at least 28 days for patients having major abdominopelvic surgery and at least 7 days for all other major surgery. Procedures meeting inclusion into the major abdominopelvic surgery risk group included colectomies, anterior resection, abdominoperineal resection, pelvic exenteration, major debulking surgery including hyperthermic intraperitoneal chemotherapy (HIPEC), and liver resections. Low and intermediate risk profile patients that were admitted to hospital received P-TP only for the duration of their hospital admission (inpatient P-TP). The Low Molecular Weight Heparin enoxaparin was used for P-TP, with a dosing regimen of 40 mg for patients between 50 and 120 kg, 20 mg for under 50 kg, and 60 mg for over 120 kg. This was prescribed as a once daily dose, subcutaneously. The dose was halved if the patient’s creatinine clearance was below 30 ml/min. Contraindications to TP were also defined. SCDs were continued postoperatively if a contraindication to P-TP administration existed or if P-TP was prescribed later than 6 hours after completion of surgery. SCD use was ceased once P-TP was re-initiated. All thromboprophylaxis decisions were made by senior clinicians (surgeons and anaesthetists) in theatre. All ongoing thromboprophylaxis orders were charted by the treating anaesthetist prior to leaving the theatre complex. The STEP risk profile was handed over to recovery nursing staff. Nursing staff ensured that mechanical measures were applied prior to leaving the anaesthetic recovery room and that ward orders were completed on the inpatient drug chart. Patient awareness of postoperative TE was improved on the ward through targeted educational brochures and risk assessment questionnaires provided at the time of surgical booking. Daily postoperative rounds were conducted by clinical pharmacists to assess and enhance compliance with STEP-P. Thromboprophylaxis orders were checked against the STEP protocol by clinical pharmacists on the ward and fed back to treating unit staff. Post-discharge TP prescriptions were signed off by clinical pharmacists and prescribed according to the minimal recommended durations. Patients were provided with education with regards to the risk of postoperative TE and self-administration techniques for enoxaparin. Discharge bundles consisting of educational material and sharps disposal bin were also provided. Prospective compliance audits were also conducted.