Intravenous dexmedetomidine, but not midazolam, prolongs bupivacaine spinal anesthesia.
OBJECTIVE
Midazolam has only sedative properties. However, dexmedetomidine has both analgesic and sedative properties that may prolong the duration of sensory and motor block obtained with spinal anesthesia. This study was designed to compare intravenous dexmedetomidine with midazolam and placebo on spinal block duration, analgesia, and sedation in patients undergoing transurethral resection of the prostate.


METHODS
In this double-blind randomized placebo-controlled trial, 75 American Society of Anesthesiologists' I and II patients received dexmedetomidine 0.5 microg . kg(-1), midazolam 0.05 mg . kg(-1), or saline intravenously before spinal anesthesia with bupivacaine 0.5% 15 mg (n = 25 per group). The maximum upper level of sensory block and sensory and motor regression times were recorded. Postoperative analgesic requirements and sedation were also recorded.


RESULTS
Sensory block was higher with dexmedetomidine (T 4.6 +/- 0.6) than with midazolam (T 6.4 +/- 0.9; P < 0.001) or saline (T 6.4 +/- 0.8; P < 0.001). Time for sensory regression of two dermatomes was 145 +/- 26 min in the dexmedetomidine group, longer (P < 0.001) than in the midazolam (106 +/- 39 min) or the saline (97 +/- 27 min) groups. Duration of motor block was similar in all groups. Dexmedetomidine also increased the time to first request for postoperative analgesia (P < 0.01 compared with midazolam and saline) and decreased analgesic requirements (P < 0.05). The maximum Ramsay sedation score was greater in the dexmedetomidine and midazolam groups than in the saline group (P < 0.001).


CONCLUSIONS
Intravenous dexmedetomidine, but not midazolam, prolonged spinal bupivacaine sensory blockade. It also provided sedation and additional analgesia.
Kaya
Fatma Nur
FN
Department of Anesthesiology and Reanimation, Uludag University Medical School, Bursa, Turkey. fnurkaya@gmail.com
Yavascaoglu
Belgin
B
Turker
Gurkan
G
Yildirim
Arzu
A
Gurbet
Alp
A
Mogol
Elif Basagan
EB
Ozcan
Berin
B
D000368:Aged; D000775:Anesthesia, Spinal / Q000379:methods; D019162:Anesthetics, Combined / Q000008:administration & dosage / Q000494:pharmacology; D000779:Anesthetics, Local / Q000008:administration & dosage / Q000494:pharmacology; D002045:Bupivacaine / Q000008:administration & dosage / Q000494:pharmacology*; D020927:Dexmedetomidine / Q000008:administration & dosage / Q000494:pharmacology*; D004311:Double-Blind Method; D004357:Drug Synergism; D006801:Humans; D006993:Hypnotics and Sedatives / Q000008:administration & dosage / Q000494:pharmacology; D008297:Male; D008874:Midazolam / Q000008:administration & dosage / Q000494:pharmacology*; D008875:Middle Aged; D009407:Nerve Block / Q000379:methods; D013997:Time Factors; D020728:Transurethral Resection of Prostate / Q000379:methods*
D019162:Anesthetics, Combined; D000779:Anesthetics, Local; D006993:Hypnotics and Sedatives; D020927:Dexmedetomidine; D008874:Midazolam; D002045:Bupivacaine