Clonidine Reduced Blood Loss, Transfusions in Pelvic/Acetabular Fracture Surgery

SAN DIEGO — Preoperative clonidine reduced intraoperative blood loss and postoperative transfusions among patients undergoing pelvic and acetabular fracture surgery, a randomized trial showed.

Intraoperative bleeding volume was 1,088.7 cc in the clonidine group compared with 1,420.9 cc in the placebo group (P<0.001), and 6.8% of patients required blood transfusion compared with 22.7%, respectively (P=0.03), reported Alireza Mirahmadi, MD, MPH, of Beth Israel Deaconess Medical Center and Harvard Medical School in Boston, at the American Academy of Orthopaedic Surgeons annual meeting.

Patients in the clonidine group also had lower pain scores based on the Visual Analogue Scale versus the placebo group (4.5 vs 6.2, P<0.001), as well as a lower mean surgical field quality score, which indicated better surgical field visibility and less bleeding (3.7 vs 5.1, respectively, P<0.001).

Post-surgery, the difference in hemoglobin level between the groups increased and became significant by day 3: 9.8 in the intervention arm versus 8.4 in the placebo arm (P=0.02).

“Preoperative oral clonidine is a simple, low-cost intervention,” Mirahmadi told MedPage Today. “Given its dual benefit on bleeding and pain, clonidine could be considered as a valuable addition to perioperative management in pelvic and acetabular fracture surgeries.”

According to Mirahmadi, high blood loss is a significant risk of surgeries for pelvic and acetabular fractures, which often result from trauma such as car accidents and falls from height. “Since the pelvis is highly vascularized, the potential for significant hemorrhage is substantial,” he said, and tourniquets can’t be used.

Current strategies to reduce bleeding include hydration, controlled hypotension, antifibrinolytics, and surgical techniques, but these approaches have limitations, he added. “A better strategy is needed to reduce bleeding without compromising hemodynamic stability or increasing thrombotic risk.”

“Clonidine has been studied in other types of surgery, particularly otologic surgeries, neurosurgery, and spine surgery, where it has shown promising results in reducing intraoperative blood loss and improving surgical field clarity,” Mirahmadi said, noting that it hasn’t been studied in trauma surgery until now.

The researchers were most surprised by the drug’s effect on the surgeon’s visual field, he said. “The clarity of the surgical field improved significantly in the clonidine group, which likely contributed to a more efficient and safer surgical process.”

The drug appears to work by decreasing bleeding from small vessels during surgery, and reducing catecholamine release and stress-induced vasoconstriction, he explained.

Clonidine is inexpensive, Mirahmadi said. While he noted that it can cause bradycardia, hypotension, and sedation, no significant adverse effects were reported in the study.

Reza Firoozabadi, MD, MA, of the University of Washington in Seattle, told MedPage Today that “this treatment effect is particularly valuable in elderly patients with acetabular fractures who require an anterior-based open reduction and internal fixation approach, where managing blood loss is critical.”

However, he cautioned that “the relatively long half-life of clonidine raises concerns regarding potential intraoperative complications, such as resistant hypotension and even the risk of stroke. Notably, the study has yet to specifically report on intraoperative blood pressure measurements between the two groups. It is essential that this aspect is thoroughly evaluated before any changes to current clinical practice are considered.”

For this study, the researchers included 88 patients referred to a tertiary hospital from March 2022 to December 2023. Patients were diagnosed with a pelvic or acetabular fracture using plain radiographs and were randomly divided into two groups. The patient, surgeon, nurses, care providers, and analyzer were blinded throughout the study. Patients with certain comorbid conditions and those already taking hypertension drugs were excluded.

Of the patients, 59.1% had acetabular fractures, and the remainder had pelvic fractures. The most common types of fractures were column fractures (34.1%) and lateral compression type 2 fractures (28.5%). Mean patient age was 38, 89.8% were men, and mean BMI was 26.4.

The intervention group received 200 mcg of oral clonidine 75 to 90 minutes before anesthesia. The control group received a placebo with a similar color and shape to clonidine.

There were no statistically significant differences between the groups for postoperative bleeding volume and duration of operation.

Limitations included an imbalance of men, a lack of simultaneous pelvic/acetabular fractures, and short-term follow-up, the researchers said.

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