Near-infrared spectrophotometry is useful to detect the beneficial pharmacological effects of alprostadil on spinal cord deoxygenation.
OBJECTIVE
The purpose of this study is to confirm our previous studies that near-infrared spectrophotometry (NIRS) can detect spinal cord ischemia earlier than evoked spinal cord potential (ESP), and to determine whether it can detect the pharmacological effect of prostaglandin E1 (PGE1) incorporated in lipid microspheres (alprostadil) on the spinal cord.


METHODS
NIRS probes were placed on the posterior side of the lower lumbar vertebrae, and oxygenated hemoglobin (oxy-Hb) of the spinal cord was monitored continuously in 14 male New Zealand white rabbits. The amplitude of ESP was recorded every minute. All rabbits underwent a normothermic infrarenal aortic cross-clamping (AXC) for 20 min, and all were pretreated with either an intravenous 3 microg/kg/10 min alprostadil (group A; n=4) or the same volume saline (group C; n=10).


RESULTS
ESP amplitude started to show a linear decrease 6 min after the onset of AXC and was comparable between groups (P=.839). Oxy-Hb decreased rapidly just after the onset of AXC, followed by monoexponential decline. It reached a plateau at 10 min after the onset of AXC. Oxy-Hb of group A was significantly higher than that of group C (P=.014).


CONCLUSIONS
NIRS can detect spinal cord ischemia earlier than ESP. It can detect the beneficial pharmacological effect of alprostadil on the spinal cord.
Kunihara
Takashi
T
Department of Cardiovascular Surgery, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
Shiiya
Norihiko
N
Matsuzaki
Kenji
K
Sata
Fumihiro
F
Matsui
Yoshiro
Y
D000527:Alprostadil / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D001831:Body Temperature / Q000187:drug effects; D004195:Disease Models, Animal; D005071:Evoked Potentials / Q000187:drug effects; D006339:Heart Rate / Q000187:drug effects; D007262:Infusions, Intravenous; D008297:Male; D008991:Monitoring, Physiologic / Q000379:methods*; D010108:Oxyhemoglobins / Q000378:metabolism*; D010865:Pilot Projects; D011817:Rabbits; D015203:Reproducibility of Results; D019265:Spectroscopy, Near-Infrared; D020760:Spinal Cord Ischemia / Q000175:diagnosis* / Q000188:drug therapy* / Q000378:metabolism; D013997:Time Factors; D014665:Vasodilator Agents / Q000008:administration & dosage / Q000494:pharmacology*
D010108:Oxyhemoglobins; D014665:Vasodilator Agents; D000527:Alprostadil