Sevoflurane and Isoflurane-Pharmacokinetics, Hemodynamic Stability, and Cardioprotective Effects During Cardiopulmonary Bypass.

OBJECTIVES: This study aimed to evaluate the pharmacokinetic profiles of sevoflurane and isoflurane during use of minimized extracorporeal circulation to perform coronary artery bypass graft surgery. Furthermore, cardiovascular stability during bypass and the postoperative release of troponins were evaluated. DESIGN: Prospective, randomized study. SETTING: University hospital. PARTICIPANTS: The study comprised 31 adult patients undergoing coronary artery bypass grafting. INTERVENTIONS: The pharmacokinetic measurements of the concentration of the volatile anesthetics in the arterial and venous blood, air inlet, air outlet, and gas exhaust of the extracorporeal circulation were recorded. Secondary end-points were cardiovascular stability during bypass, amount of postoperative release of troponin, time to extubation, time to discharge from the intensive care unit and the hospital, and 30-day mortality. MEASUREMENTS AND MAIN RESULTS: Thirty patients completed the protocol. The pharmacokinetics of isoflurane and sevoflurane were almost identical, with a rapid wash-in (time to reach 50% of arterial steady state) concentration of 0.87±0.97 minutes and 1.14±0.35 minutes for isoflurane and sevoflurane, respectively, and a biphasic venous elimination with a terminal half-life of approximately 10 minutes for both compounds. There was a correlation between the gas inlet and the gas exhaust of the extracorporeal circulation. No difference in cardiovascular stability was found. High-sensitivity troponin concentrations on the first postoperative morning were 0.355±0.312 µg/mL and 0.225±0.111 µg/mL in the isoflurane and sevoflurane groups, respectively (p = 0.147). CONCLUSIONS: The study found similar pharmacokinetics regarding wash-in and wash-out for sevoflurane and isoflurane. In addition, no difference in cardiovascular stability was found. The markers of cardiac damage were not different between the two anesthetics. Based on these data, sevoflurane and isoflurane might be used equivalently in patients undergoing coronary artery bypass graft surgery with extracorporeal circulation.

Correlation of (99m) Tc-DPD SPECT/CT Scan Findings and Diagnostic Blockades of Lumbar Medial Branches in Patients with Unspecific Low Back Pain in a Randomized-Controlled Trial.

OBJECTIVE: Zygapophyseal joints are the origin of pain in up to 30% of those with unspecific chronic low back pain. Until recently, no reliable clinical tests have been found to identify the patients who would benefit from denervation of the zygapophyseal joints by medial branch blockades. DESIGN: We performed a prospective randomized placebo-controlled trial to evaluate the value of high-resolution single-photon emission computed tomography (SPECT)/computed tomography (CT) of the lumbar spine prior to any diagnostic infiltration of the medial branches. METHODS: Patients with suspected zygapophyseal joint-related pain were included in the study. After obtaining a SPECT/CT scan of the lumbar spine a set of infiltrations of the medial branches was done with local anesthetics and placebo on different days. Patients and anesthetists were blinded to the results of SPECT/CT and to the infiltrated agents. RESULTS: In a total of 29 study patients, 7 had positive and 22 negative infiltration tests, and 9 had positive and 20 negative SPECT/CT findings. Sensitivity of SPECT/CT for a positive response after diagnostic infiltration was 0.57 (95% confidence interval [CI] 0.18-0.90); specificity was 0.77 (CI 95% 0.55-0.92); odds ratio was 4.53 (CI 95% 0.75-27.40); and diagnostic accuracy was 0.72. CONCLUSION: Compared with diagnostic infiltrations SPECT/CT scans showed only a moderate sensitivity and specificity and, therefore, may not be recommended as a first line diagnostic tool prior to diagnostic infiltrations.