title: Spinal oxygenation, blood supply localization, cooling, and function with aortic clamping.
abstract: Similar to other methods of organ preservation, "spinoplegia" may protect the spinal cord from the effects of oxygen desaturation during aortic cross-clamping. In porcine experiments, spinal cord O2 saturation was studied during intraoperative localization of the blood supply to the spinal cord using hydrogen; division of arteries not supplying the spinal cord; aortic cross-clamping for 60 minutes; and 60 minutes after unclamping. In 5 animals, 120 mL of cold saline solution with lidocaine (100 mg/dL) was infused into the aorta during aortic cross-clamping. During sequential localization, O2 saturation dropped by 40.02% (standard deviation, 20.16%) for T-14 artery testing versus a decrease of 17.27% (standard deviation, 11.88%; p = 0.0075) for L-5 artery segment testing in the control animals and returned to baseline thereafter. During aortic cross-clamping maximal O2 desaturation was 5% of baseline (15.7%; p less than 0.0001), which improved slightly by 30 minutes after clamping (48% of baseline +/- 37.37%; p = 0.048 versus maximum) and then returned to baseline (97.1% of baseline +/- 41%) with unclamping; 5 minutes later, hyperoxygenation occurred with a progressive decline thereafter (68% of baseline +/- 29.3%; p = 0.025, 45 minutes after unclamping versus baseline). The decrease in spinal motor evoked potentials was significantly less (p less than 0.02) in the treated group. Intraoperative hydrogen testing in 8 patients was demonstrated to be safe. It accurately localized reattached arteries, and O2 saturation of the spinal cord fell by 56% (standard deviation, 29%; p = 0.0025) with aortic cross-clamping. We conclude that spinal cord ischemia occurs with aortic cross-clamping in both animals and humans.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Surgery, Baylor College of Medicine, Houston, Texas 77030.
authors.forename: L G
authors.initials: LG
authors.lastname: Svensson
authors.forename: E S
authors.initials: ES
authors.lastname: Crawford
authors.forename: V
authors.initials: V
authors.lastname: Patel
authors.forename: T R
authors.initials: TR
authors.lastname: McLean
authors.forename: J W
authors.initials: JW
authors.lastname: Jones
authors.forename: M E
authors.initials: ME
authors.lastname: DeBakey
mesh_terms: D000818:Animals; D001012:Aorta, Abdominal / Q000601:surgery*; D001013:Aorta, Thoracic / Q000601:surgery*; D003250:Constriction; D006801:Humans; D007511:Ischemia / Q000378:metabolism*; D008012:Lidocaine / Q000627:therapeutic use*; D008297:Male; D010101:Oxygen Consumption; D011183:Postoperative Complications / Q000517:prevention & control*; D013116:Spinal Cord / Q000098:blood supply* / Q000187:drug effects / Q000378:metabolism*; D013552:Swine
chemical_list: D008012:Lidocaine