Dexmedetomidine infusion is associated with enhanced renal function after thoracic surgery.
OBJECTIVE
To test the hypothesis that dexmedetomidine, a selective alpha-2 agonist, enhances urine flow rate and perioperative renal function, a post hoc analysis was conducted on a recently completed study of dexmedetomidine used as an adjunct to epidural analgesia after thoracotomy.


METHODS
Post hoc analysis of a randomized, placebo-controlled, double-blind clinical trial.


METHODS
Tertiary-care university medical center.


METHODS
28 patients undergoing elective thoracotomy.


METHODS
Patients were prospectively randomized to receive a supplemental 24-hour intravenous infusion of either dexmedetomidine (0.4 microg kg(-1) h(-1), n = 14) or saline placebo (equivalent infusion rate, n = 14).


METHODS
Available renal parameters including urine output, calculated creatinine clearance (cCl(Cr)), daily serum creatinine level (S(Cr)), and the fractional change in S(Cr) level (DeltaS(Cr)%, [peak postoperative S(Cr) - baseline S(Cr)] / baseline S(Cr)) x 100) were recorded.


RESULTS
Values are expressed as means +/- SD. There were no significant differences in baseline values between the groups. The dexmedetomidine group had significantly greater cumulative urine output at postoperative hour 4 (473 +/- 35 vs 290 +/- 122 mL, P = 0.001) and 12 (1033 +/- 240 vs 822 +/- 234 mL, P = 0.02), although only 14% of the group received diuretic agents, compared with 43% in the control group. The dexmedetomidine group had significantly better preserved perioperative renal function compared with the control group, as assessed by DeltaS(Cr)% (0.04% decrease vs 21% increase, P = 0.0007) and cCl(Cr) (75.3 +/- 13.2 vs 62.5 +/- 15.5 mL/min, P = 0.02).


CONCLUSIONS
Dexmedetomidine infusion administered as a supplement to epidural analgesia induced diuresis in postthoracotomy patients with normal preoperative renal function and undergoing fluid restriction. Although this finding may represent simple reversal of a tubular antidiuresis, the lower DeltaS(Cr)% and preservation of cCl(Cr) suggest a beneficial effect on glomerular filtration compared with controls.
Frumento
Robert J
RJ
Department of Anesthesiology, College of Physicians and Surgeons of Columbia University, New York, NY 10032-3784, USA.
Logginidou
Helene G
HG
Wahlander
Staffan
S
Wagener
Gebhard
G
Playford
Hugh R
HR
Sladen
Robert N
RN
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D000328:Adult; D000368:Aged; D015360:Analgesia, Epidural; D020927:Dexmedetomidine / Q000008:administration & dosage / Q000494:pharmacology*; D004311:Double-Blind Method; D005260:Female; D005919:Glomerular Filtration Rate / Q000187:drug effects; D006801:Humans; D007668:Kidney / Q000187:drug effects* / Q000502:physiology; D007677:Kidney Function Tests; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D013908:Thoracotomy
D000316:Adrenergic alpha-Agonists; D020927:Dexmedetomidine