Clevidipine compared with nitroglycerin for blood pressure control in coronary artery bypass grafting: a randomized double-blind study.

PURPOSE: We tested the hypothesis that clevidipine, a rapidly acting dihydropyridine calcium channel blocker, is not inferior to nitroglycerin (NTG) in controlling blood pressure before cardiopulmonary bypass (CPB) during coronary artery bypass grafting (CABG). METHODS: In this double-blind study from October 4, 2003 to April 26, 2004, 100 patients undergoing CABG with CPB were randomized at four centres to receive intravenous infusions of clevidipine (0.2-8 µg·kg(-1)·min(-1)) or NTG (0.4 µg·kg(-1)·min(-1) to a clinician-determined maximum dose rate) from induction of anesthesia through 12 hr postoperatively. The study drug was titrated in the pre-CPB period with the aim of maintaining mean arterial pressure (MAP) within ± 5 mmHg of a clinician-predetermined target. The primary endpoint was the area under the curve (AUC) for the total time each patient's MAP was outside the target range from drug initiation to the start of CPB, normalized per hour (AUCMAP-D). The predefined non-inferiority criterion for the primary endpoint was a 95% confidence interval (CI) upper limit no greater than 1.50 for the geometric means ratio between clevidipine and NTG. RESULTS: Total mean [standard deviation (SD)] dose pre-bypass was 4.5 (4.7) mg for clevidipine and 6.9 (5.4) mg for NTG (P < 0.05). The geometric mean AUCMAP-D for clevidipine was 283 mmHg·min·hr(-1) (n = 45) and for NTG was 292 mmHg·min·hr(-1) (n = 48); the geometric means ratio was 0.97 (95% CI 0.74 to 1.27). The geometric mean AUCMAP-D during aortic cannulation was 357.7 mmHg·min·hr(-1) for clevidipine compared with 190.5 mmHg·min·hr(-1) for NTG. Mean (SD) heart rate with clevidipine was 76.0 (13.8) beats·min(-1) compared with 81.5 (14.4) beats·min(-1) for NTG. There were no clinically important differences between groups in adverse events. CONCLUSION: During CABG, clevidipine was not inferior to NTG for blood pressure control pre-bypass.

The Surgical Procedure Assessment (SPA) score predicts intensive care unit length of stay after cardiac surgery.

OBJECTIVE: The ability to predict intensive care unit length of stay greatly facilitates triage and resource allocation for postoperative cardiac surgical patients in the intensive care unit. We developed a simple, intuitive Surgical Procedure Assessment score that integrates surgical complexity (1, low; 2, intermediate; 3, high) with patient comorbidity (A, minimal; B, substantial). We hypothesized that the Surgical Procedure Assessment score would predict intensive care unit length of stay, discriminate preoperatively between fast-track and prolonged-stay patients, and compare favorably with more complex risk scores. METHODS: After institutional review board approval, 1201 cardiac surgical patients were preoperatively assigned a Surgical Procedure Assessment score, as well as a Parsonnet, Tuman, Tu, and Cardiac Anesthesia Risk Evaluation score. We compared these scores with regard to prediction of intensive care unit length of stay, as well as their concordance in predicting intensive care unit length of stay of less than 48 hours (fast track) and more than 7 days (prolonged stay). RESULTS: Intensive care unit length of stay increased significantly with increasing Surgical Procedure Assessment scores (P < .01, Cuzick's test for trend). The lowest Surgical Procedure Assessment score (1A) predicted intensive care unit length of stay of less than 48 hours, and the higher Surgical Procedure Assessment scores (2B or 3) predicted intensive care unit length of stay of more than 7 days more accurately than the Parsonnet, Tuman, Tu and Cardiac Anesthesia Risk Evaluation scores. CONCLUSIONS: The Surgical Procedure Assessment score predicts intensive care unit length of stay better than other comparable scores. It is simple, intuitive, and easily understood by all caregivers and can preoperatively discriminate fast-track from prolonged-stay patients. It is a useful tool to facilitate intensive care unit triage.

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.

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.