One discussion this week involved preoperative epidurals and chemical prophylaxis.
Reference: Manguso N, et al. The impact of epidural analgesia on the rate of thromboembolism without chemical thromboprophylaxis in major oncologic surgery. The American Surgeon. 2018 Jun 1;84(6):851-855.
Summary: General surgery patients are at a particularly high risk of developing deep vein thrombosis (DVT) without prophylaxis and some data suggest their risk increases 2-fold if an underlying malignancy is present. A meta-analysis by Leonardi et al (2007) found that without chemical prophylaxis, the rate of DVT is as high as 35%, which drops to 12% if a patient receives chemical prophylaxis.
Although the use of chemical prophylaxis to reduce the risk of thromboembolic events has been validated in numerous studies, these drugs increase the risk of bleeding. Risk of bleeding in the setting of epidural analgesia may put the patient at risk for the potentially catastrophic complication of epidural hematoma which may lead to long-term paralysis.
Manguso et al (2018) evaluated the rate of thromboembolic events in cancer patients undergoing major oncologic abdominal and/or pelvic surgery who had a preoperative epidural catheter (EC) placed for postoperative pain control.
The aim of this study was to evaluate the need for chemical thromboprophylaxis in patients undergoing major abdominal or pelvic oncologic surgery with preoperative EC placement for postoperative pain control. Of the 285 patients for whom data were collected over this five-year period, the rates of above knee and below-knee DVTs were 3.2 and 5.2%, respectively. These patients were all asymptomatic and had no serious adverse events occur secondary to the identified thromboses.
A secondary finding was that 2.5% of patients had above-knee DVT before undergoing surgery; thus, it is important to consider the patient’s risk factors for DVT and screen preoperatively if there is concern.
Our data suggest that patients undergoing major open operations with epidural analgesia have low rates of DVT and may obviate the need for chemical prophylaxis. However, larger studies are required to determine the overall effects of epidural analgesia on the development of DVTs postoperatively.