Con : Surgery should not proceed when a bloody tap occurs during spinal drain placement for elective thoracoabdominal aortic surgery

t RAINING SPINAL FLUID to reduce spinal fluid pressure during aortic occlusion has been shown to reduce paralyis after thoracoabdominal aortic repair1,2 and the use of spinal rains has become the standard of care in thoracoabdominal ortic (TAA) surgery. Despite strong evidence supporting the herapeutic benefit of spinal fluid drainage, controversy exists bout the management of spinal drains. Puncture of the intrahecal space with a large-bore needle and placement of an ntrathecal catheter have associated risks, especially in patients ho will be heparinized after catheter placement. Vascular njury resulting in spinal hematoma is one of the most feared omplications in this setting. Currently there are no evidenceased recommendations about how to proceed when bleeding is ncountered during spinal drain placement. However, informaion about bleeding encountered in neuraxial anesthesia techiques and lumbar puncture is relevant to this question. The incidence of bloody tap in lumbar puncture and euraxial anesthetic techniques ranges from 1% to 10%.3-5 leeding can be venous or arterial6 and presents in several ays. Blood-tinged spinal fluid may appear briefly when the eedle enters the intrathecal space, persistent blood tinged fluid ay drain from the catheter, or frank blood may be aspirated rom the needle or catheter during placement. In practice, when lacing spinal drains, it is not unusual to see blood-tinged pinal fluid that clears after the first few drops when the needle nters the intrathecal space. However, fluid that remains bloody ndicates ongoing bleeding, however small, and being able to ithdraw blood during drain placement confirms that a largeore needle is in a vessel of sufficient size to permit free spiration. Spinal hematomas may be epidural, subdural, or subarachoid in location and are thought to be caused by bleeding from adicular arteries that run along the nerve roots or from the pidural venous plexus. These valveless spinal veins commuicate with abdominal and thoracic veins and are susceptible to ongestion caused by increased intra-abdominal or central veous pressure.6,7 Precise data on the etiopathogenesis and incience of spinal hematoma are lacking. A literature survey and eta-analysis of 613 case studies of spinal hematoma pubished between 1926 and 1996 showed that neuraxial anesthetic echnique alone was the tenth most common cause of hemaoma, and lumbar puncture or neuraxial anesthetic technique ombined with anticoagulation represented the fifth most comon cause. Trauma and technical difficulty with needle placeent were associated with spinal hematoma.7 Based on review of case reports, spinal hematoma after euraxial anesthesia is a rare complication, with an estimated ncidence of fewer than 1 in 150,000 epidural and 1 in 220,000 pinal anesthetics.8,9 However, studies that find very low risk of pinal hematoma after neuraxial techniques do not necessarily ean the risk is very low in all populations. A literature search f neuraxial anesthetic techniques between 1906 and 1994 ound 61 cases of spinal hematoma after spinal or epidural nesthetics.10 Sixty-eight percent of the spinal hematomas were ssociated with perioperative coagulopathy and/or anticoaguc