To the Editor:—  I read with great interest the excellent article by Dr. Gelman in which he discusses the function of the human venous system.1Although this review is most comprehensive, it does not detail the role of venous pressure in spinal cord perfusion. This aspect deserves attention because it may influence the management of spinal cord ischemia after thoracoabdominal aortic aneurysm repair.2In a recent review of 858 thoracoabdominal aneurysm repairs (1990–2006), Dr. Etz et al.  2described the association between postoperative paraplegia and higher mean central venous pressures in the first 5 postoperative hours. Conceptually, this observation makes sense given that net spinal cord perfusion pressure depends on the arteriovenous pressure difference.

As a result, the manipulation of central venous pressure may improve spinal cord perfusion pressure and reverse paraplegia after thoracic aortic surgery. This has already been described for cerebrospinal fluid pressure, where its drainage may significantly impact the management of postoperative paraplegia in this setting.3 

I congratulate Dr. Gelman on his excellent article that has highlighted the importance of the venous system. I look forward to his comments about the role of venous pressure in the pathophysiology of spinal cord ischemia after descending thoracic aortic reconstruction.

Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania.

Gelman S: Venous function and central venous pressure: A physiologic story. Anesthesiology 2008; 108:735–48
Etz CD, Luehr M, Kari FA, Bodian CA, Smego D, Plestis K, Griepp RB: Paraplegia after extensive thoracic and thoracoabdominal aortic aneurysm repair: Does critical spinal cord ischemia occur postoperatively? J Thorac Cardiovasc Surg 2008; 135:324–30
Cheung AT, Weiss SJ, McGarvey ML, Stecker MM, Hogan MS, Escherich A, Bavaria JE: Interventions for reversing delayed-onset postoperative paraplegia after thoracic aortic reconstruction. Ann Thorac Surg 2002; 74:413–9