Risk of Hematoma After Epidural Anesthesia and Analgesia for Cardiac Surgery

Abstract

To the Editor: We read Dr. Chaney’s excellent review on neuraxial block for cardiac surgery (1). As he points out, the risk of neuraxial hematoma remains a great concern (1). Unfortunately, the true risk is difficult to precisely quantify (2). To help clinicians decide whether neuraxial block is worthwhile, we should report all successful cases and series, as well as occurrences of neuraxial hematoma and other major complications. To this end, we bring to your attention the following two cases: one reported in a newsletter (3) and the second in a surgical journal (4). In the first case, a 60-yr-old man underwent coronary artery bypass grafting (3). His preoperative platelet count and coagulation were normal (antiplatelet medication status not stated). Prior to surgery, an 18-G epidural catheter was inserted at T12/L1. No bleeding was noted. The patient was heparinized 1 h after induction of anesthesia. Surgery was uneventful, with normal blood loss. Protamine, 4 U of fresh-frozen plasma, and 6 U of platelets were given. An epidural infusion of fentanyl and bupivacaine was given postoperatively. The next morning, the patient’s trachea was extubated. At that time, he was able to move his upper limbs, but his legs had no movement or sensation, a condition that persisted despite discontinuation of the epidural infusion. A magnetic resonance imaging (MRI) scan that afternoon revealed a hematoma from T5 to T10 with cord displacement. Four hours later, he underwent laminectomy. The patient remained paraplegic. In the second case a 65-yr-old patient with diabetes underwent minimally invasive direct coronary artery bypass grafting under combined general-epidural anesthesia (4). Postoperative paraplegia developed after the patient presented with anterior spinal artery syndrome. The risk of catastrophic neurologic complication after neuraxial block is increased by the fact that assessing lower limb functions may be difficult and delayed. Further delay could occur if a patient needs to be kept sedated and tracheally intubated after cardiac surgery because of hemodynamic instability, bleeding, and/or surgical re-exploration. One can also imagine that it would be hazardous to place a patient in the prone position for emergency laminectomy after recent cardiac surgery. In addition, there are two reports of spontaneous epidural hematoma after cardiac surgery without epidural instrumentation (5,6). Thus, there is the possibility that hematoma can spontaneously occur at sites of epidural placement. Two other patients suffered from this complication after epidural catheters were placed before cardiac surgery scheduled for the following day (7,8). Conceivably, if surgery had immediately followed, the consequence could have been worse. There are other considerations. First, inserting an epidural catheter the night before surgery theoretically reduces the risk of hematoma, but it necessitates early admission. Second, if epidural catheterization occurs just before induction of anesthesia, theoretically the risk of hematoma increases for the rare patient who has to be put on cardiopulmonary bypass urgently due to hemodynamic instability. Furthermore, the risks to patients from postponing a case after a bloody tap are significant. Finally, 3% of catheterizations were unsuccessful in one series (9). Multiple attempts put the patient at risk of neuraxial complications, even if no catheter is inserted, and thus the patient is afforded no benefits of neuraxial block. Anthony M.-H. Ho, MS, MD, FRCPC, FCCP Peggy T. Y. Li, MB, ChB Manoj K. Karmakar, MD, FRCA Department of Anaesthesia and Intensive Care The Chinese University of Hong Kong Prince of Wales Hospital, Shatin, NT Hong Kong Special Administrative Region of the People’s Republic of China [email protected]