Aspects of the spinal cord circulation as assessed by intrathecal oxygen tension monitoring during various arterial interruptions in the pig.
OBJECTIVE
We sought to study the effect of various modes of interruption of the spinal cord blood supply on intrathecal oxygenation.


METHODS
In 24 pigs intrathecal PO (2), PCO (2), and pH were continuously monitored with a multiparameter catheter (Paratrend 7, Biomedical Sensors; Diametrics Medical, Inc, St Paul, Minn) during and after aortic crossclamping or selective interruption of segmental arteries and proximal collateral circulation.


RESULTS
Proximal aortic clamping (n = 6) produced complete ischemia, whereas a second clamp close to the celiac trunk (n = 4) partly protected against spinal cord ischemia. This is explained by prevention of the steal phenomenon in the excluded part of the aorta. Adding clamps to the subclavian arteries (n = 6) created complete spinal ischemia as the collateral circulation was interrupted. In another group (n = 4) all segmental arteries below T5 were occluded with no reaction in the intrathecal variables. Additional selective clamping of supreme intercostal arteries (n = 4) showed the relative importance of the subclavian and vertebral collateral pathways.


CONCLUSIONS
Continuous intrathecal PO (2) was monitored during various modes of interruption of the spinal cord blood supply. This provided insight into the ischemia mechanisms and relative importance of the segmental contribution and proximal collateral pathways of the spinal cord circulation in pigs. A short literature review is given, and aspects of comparative anatomy are discussed.
Departments of Anesthesiology and Surgery, University Hospital, Uppsala, SE-751 85 Sweden. lennart.christiansson@anestesi.uu.se
L
L
Christiansson
A T
AT
Ulus
A
A
Hellberg
D
D
Bergqvist
L
L
Wiklund
S
S
Karacagil
D000818:Animals; D001783:Blood Flow Velocity; D003097:Collateral Circulation; D005260:Female; D008297:Male; D010092:Oximetry / Q000379:methods*; D010100:Oxygen / Q000032:analysis*; D013116:Spinal Cord / Q000098:blood supply* / Q000000981:diagnostic imaging; D020760:Spinal Cord Ischemia / Q000000981:diagnostic imaging / Q000378:metabolism / Q000503:physiopathology / Q000517:prevention & control; D013129:Spinal Puncture; D013348:Subclavian Artery / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D013552:Swine; D018608:Ultrasonography, Doppler; D014711:Vertebral Artery / Q000033:anatomy & histology / Q000000981:diagnostic imaging
D010100:Oxygen