Dexmedetomidine infusion is associated with enhanced renal function after thoracic surgery.

STUDY 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. DESIGN: Post hoc analysis of a randomized, placebo-controlled, double-blind clinical trial. SETTING: Tertiary-care university medical center. PATIENTS: 28 patients undergoing elective thoracotomy. INTERVENTIONS: 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). MEASUREMENTS: 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. MAIN 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). CONCLUSION: 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.

Mandatory ethics consultation policy.

OBJECTIVE: To describe ethics consultations at a single institution that has a mandatory ethics consultation policy. PATIENTS AND METHODS: We retrospectively reviewed the medical records of all adult patients who were admitted to the intensive care unit at Columbia University Medical Center and had an ethics consultation between August 1, 2006, and July 31, 2007. All mandatory and nonmandatory ethics consultations were reviewed. Patient diagnosis, prognosis, presence of do-not-resuscitate order, presence of written advance directives, reason for the ethics consultation, and survival data were collected. The number of ethics consultations hospital-wide from January 1, 2000, to December 31, 2007, was collected. RESULTS: The total number of mandatory and nonmandatory ethics consultations requested was 168. Of these consultations, 108 (64%) were considered mandatory, and 60 (36%) were considered nonmandatory. Between January 1, 2000, and December 31, 2007, the total number of ethics consultations increased 84%. CONCLUSION: The increase in the total number of ethics consultations is interpreted as a positive outcome of the mandatory policy. The mandatory ethics consultation policy has possibly increased exposure to ethics consultant-physician interactions, increased learning for physicians, and raised awareness among physicians and nurses of potential ethics assistance.

A prospective, double-blind, randomized, placebo-controlled study of dexmedetomidine as an adjunct to epidural analgesia after thoracic surgery.

OBJECTIVE: The purpose of this study was to test the hypothesis that after thoracic surgery, the supplementation of a low-dose thoracic epidural (ED) bupivacaine (0.125%) infusion by intravenous (IV) dexmedetomidine decreases analgesic requirement without causing respiratory depression. The primary endpoint was the need for additional ED bupivacaine administered through patient-controlled epidural analgesia (PCEA). Secondary endpoints included the requirement for supplemental opioids and the impact of dexmedetomidine on CO2 retention. DESIGN: A prospective, randomized, double-blinded study. SETTING: A major US tertiary care university hospital. PATIENTS: Twenty-eight patients scheduled to undergo elective thoracotomy for wedge resection, lobectomy, or pneumonectomy. INTERVENTIONS: On intensive care unit arrival, the thoracic ED catheter was loaded with 0.125% bupivacaine to a T4 sensory level and a continuous infusion of 0.125% bupivacaine without opioid was commenced at 4 mL/h. Patients were then randomized into 1 of 2 groups. The dexmedetomidine group received an IV loading dose of dexmedetomidine of 0.5 microg/kg over 20 minutes, followed by continuous IV infusion at 0.4 microg/kg/h. The placebo group received IV saline at the same calculated loading and infusion rates by volume. If necessary, supplemental analgesia (increased ED rate, ED fentanyl, ketorolac [IV]) was provided to ensure a visual analog scale (VAS) score of < or =3. MEASUREMENTS: The analgesic effect was monitored by the VAS, and the requirement for PCEA dosing and additional analgesics was recorded. Heart rate, blood pressure, and blood gases were also monitored. MAIN RESULTS: There was no significant difference in PCEA use and VAS score between the 2 groups, but requirement for supplemental ED fentanyl analgesia was significantly greater in the placebo group (66.1 +/- 95.6 v 5.3 +/- 17.1 microg, p = 0.039). Mean PaCO2 was also significantly greater in the placebo group (40.3 +/- 4.1 v 43.9 +/- 4.3 mmHg, p = 0.04). Patients in the dexmedetomidine group exhibited significantly decreased heart rate (1 patient required and responded to atropine) and blood pressure (4 patients required and readily responded to IV fluid) compared with the placebo group. CONCLUSION: The authors conclude that in postthoracotomy patients, IV dexmedetomidine is a potentially effective analgesic adjunct to thoracic ED bupivacaine infusion and may decrease the requirement for opioids and potential for respiratory depression.