Motor and somatosensory evoked potentials: their role in predicting spinal cord ischemia in patients undergoing thoracoabdominal aortic aneurysm repair with regional lumbar epidural cooling.
BACKGROUND
Paraplegia is a devastating complication for patients undergoing repair of thoracoabdominal aortic aneurysms. A monitor to detect spinal cord ischemia is necessary if anesthesiologists are to intervene to protect the spinal cord during aortic aneurysm clamping.


METHODS
The medical records of 60 patients who underwent thoracoabdominal aortic aneurysm repair with regional lumbar epidural cooling with evoked potential monitoring were reviewed. The authors analyzed latency and amplitude of motor evoked potentials, somatosensory evoked potentials, and H reflexes before cooling and clamping, after cooling and before clamping, during clamping, and after release of aortic cross clamp.


RESULTS
Twenty minutes after the aortic cross clamp was placed, motor evoked potentials had 88% sensitivity and 65% specificity in predicting spinal cord ischemia. The negative predictive value of motor evoked potentials at 20 min after aortic cross clamping was 96%.


CONCLUSIONS
Rapid loss of motor evoked potentials or H reflexes after application of the aortic cross clamp identifies a subgroup of patients who are at high risk of developing spinal cord ischemia and in whom aggressive anesthetic and surgical interventions may be justified.
Shine
Timothy S J
TS
Department of Anesthesiology, Mayo Clinic, Jacksonville, Florida, USA.
Harrison
Barry A
BA
De Ruyter
Martin L
ML
Crook
Julia E
JE
Heckman
Michael
M
Daube
Jasper R
JR
Stapelfeldt
Wolf H
WH
Cherry
Kenneth J
KJ
Gloviczki
Peter
P
Bower
Thomas C
TC
Murray
Michael J
MJ
D000368:Aged; D017545:Aortic Aneurysm, Thoracic / Q000503:physiopathology / Q000601:surgery*; D004824:Epidural Space / Q000502:physiology*; D019054:Evoked Potentials, Motor / Q000502:physiology*; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D005260:Female; D006801:Humans; D007036:Hypothermia, Induced / Q000295:instrumentation / Q000379:methods*; D008161:Lumbosacral Region / Q000502:physiology; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000295:instrumentation / Q000379:methods; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D020760:Spinal Cord Ischemia / Q000503:physiopathology / Q000517:prevention & control*