Does remifentanil attenuate renal ischemia-reperfusion injury better than dexmedetomidine in rat kidney?

BACKGROUND: Ischemia-reperfusion (I/R) injury is a common cause of patient morbidity and mortality in the perioperative period. Patients undergoing long-lasting, abdominal, and urogenital surgeries with risk factors such as advanced age, peripheral artery disease, diabetes mellitus, renovascular disease, and congestive heart failure are candidates for acute kidney injury (AKI) due to impaired renal perfusion and decreased functional renal reserve. Pharmacological agents with multiple functions and anti-oxidative and anti-inflammation properties may be promising preventative strategies for AKI. Recently, dexmedetomidine (dex) has been postulated to have renoprotective effects. OBJECTIVES: We aimed to investigate the protective effects of an intravenous anesthetic remifentanil in renal I/R injury in the rat in comparison with dex. MATERIALS AND METHODS: A total of 30 Sprague Dawley adult rats were randomly assigned into five groups: the control group (group C, n=6), the sham group (group Sh, n=6, saline-infused rats without I/R injury), the saline group (group S, n=6, saline-infused rats with I/R injury), the remifentanil-treated group (group REM, n=6), and the dexmedetomidine-treated group (group DEX, n=6). The infusions (saline, remifentanil, and dex) were started after anesthesia induction and right nephrectomy and continued until the end of the surgical procedure. In I/R injury groups, the left renal artery and vein were occluded together by a clamp for 30 minutes and reperfusion lasted for 30 minutes. The rats were sacrificed after reperfusion, and the left kidney tissue was harvested. Blood samples were drawn from all animals to evaluate plasma neutrophil gelatinase-associated lipocalin (NGAL) at the beginning, 15 minutes after ischemia, 15 minutes after reperfusion, and 6 hours after the surgical procedure (T0, T1, T2, and T3, respectively). RESULTS: The plasma NGAL levels exhibited increase at T1, T2, and T3 compared to the levels at T0 in group S (P<0.05). In group REM, there was a significant increase in plasma NGAL levels at T3 in comparison to those at T0, T1, and T2. The plasma NGAL levels at T2 in group S were significantly higher than those at T2 in group DEX (P<0.05). The groups S and REM showed significantly higher plasma NGAL levels at T3 compared to those at T0 (P<0.05). Upon histological examination, there was no difference among the study groups when left kidneys were evaluated (P>0.05). CONCLUSION: The NGAL levels and histopathological findings reflected protection by dex against renal I/R injury. However, the same exact results could not be mentioned for remifentanil depending on our study results.

Comparison of the efficacy of different concentrations and volumes of levobupivacaine in axillary brachial plexus blockade.

BACKGROUND: The aim of this study was to compare the effect of the same dosage but different concentrations and volumes of levobupivacaine used for axillary block on the onset and intensity of the block. METHODS: Sixty-nine patients were randomly allocated into three groups. The patients in Group 5, Group 7.5 and Group 3.75 were administered 45 mL of levobupivacaine (5 mg/mL), 30 mL of levobupivacaine (7.5 mg/mL) and 30 mL of levobupivacaine (7.5 mg/mL) mixed with 30 mL of 0.9% NaCl solution, respectively. The onset and intensity of sensory and motor blocks distributed through 4 nerves, duration of analgesia, and total analgesic consumption within 24 hr were recorded. RESULTS: Onset of sensory block on median and radial nerves in Group 3.75 was found to be significantly longer compared to Group 5 and Group 7.5 (P<0.05). Onset of motor block on radial nerves in cases in Group 3.75 was significantly longer compared to those in Group 7.5 (P<0.01). In Group 3.75 the intensity of sensorial blockade at the median ulnar and radial nerves and the intensity of motor blockade at the radial and musculocutaneous nerves were significantly lower than in the other two groups. The duration of analgesia in the patients of Group 5 was significantly shorter compared to those in Groups 7.5 and 3.75 (P<0.01). CONCLUSION: Decreasing the concentration and increasing the volume of levobupivacaine without changing its dosage prolongs the duration of analgesia, although it delays the onset and decreases the intensity of sensory and motor block in axillary block.

Association between ABCB1 gene polymorphisms and fentanyl's adverse effects in Turkish patients undergoing spinal anesthesia.

The ATP-binding cassette transporter (ABCB1) gene product, P-glycoprotein plays an important role in the prevention of intracellular accumulation of potentially toxic substances and metabolites in various tissues. Single nucleotide polymorphisms in this gene are claimed to be correlated with changes in the function of P-glycoprotein. There is evidence that fentanyl, may be a substrate for P-glycoprotein. The aim of the study was to assess whether an association exists between ABCB1 gene polymorphism and early respiratory and sedative adverse effects of intravenous fentanyl in Turkish patients who underwent spinal anesthesia In all 83 unrelated Turkish patients were enrolled in this study. In this study, spinal anesthesia was provided and a single dose of intravenous fentanyl (2.5µg.kg(-1)) at the beginning of surgery was used as a sedative agent. Bispectral index, respiration rate and peripheral oxygen saturation were measured continuously and recorded throughout the study. The allele and genotype frequencies were similar to previous data from Turkish population. Respiratory rate (RR) and SpO(2) parameters of the patients did not show any significant difference according to the genotype distribution for C1236T and C3435T SNPs. Fentanyl-induced decrease in respiration rate was most remarkable at 15min (23%) in CC genotype of C1236T, whereas in TT genotype of C3435T (18%) polymorphism. SpO(2) parameters in allele distribution were also not significant among the groups (p=0.374, p=0.985, respectively). For the C1236T polymorphism, patients carrying T allele showed a significant decrease in pH, and a significant increase in pCO(2) (p<0.001). ABCB1 polymorphisms did not seem to have a significant effect on sedation and respiratory depression caused by intravenous fentanyl in spinal anesthesia in Turkish patients.

Volatile anesthetics and mucociliary clearance.

BACKGROUND: The aim of this prospective, randomized, double blind study was to evaluate the possible modification of in vivo nasal mucociliary clearance by three different volatile agents: sevoflurane, isoflurane and desflurane, following intravenous induction and tracheal intubation. METHODS: Following institutional approval and informed consent, 60 patients scheduled for ear and neck surgery under general anaesthesia were randomized into three groups. Each group received sevoflurane (Group S), isoflurane (Group I) or desflurane (Group D) at 1 MAC concentrations after anaesthesia induction with propofol, remifentanil and tracheal intubation with cis-atracurium. Mucociliary clearance time was assessed by in vivo saccharin transit time (STT). We recorded the time elapsed until the first recognition of sweet taste, which was taken to represent transport of saccharin to the oropharynx. We noted the time in minutes at two time points, pre- and post-anaesthesia, under the same climatic conditions (room temperature 23 degrees C, relative humidity 60%). RESULTS: The mean STT values after sevoflurane, isoflurane and desflurane anaesthesia were 9.1+/-4.3, 6.7+/-2.8 and 7.1+/-3.1 min respectively (P>0.05). These were not significantly different among volatile anaesthetics in two measurements. CONCLUSION: Anaesthesia with volatile agents does not modify mucociliary clearance of nasal epithelium.

Tramadol does not prolong the effect of ropivacaine 7.5 mg/ml for axillary brachial plexus block.

BACKGROUND: The aim of this prospective, randomized, double-blind study was to evaluate the effect of the addition of tramadol to ropivacaine on the onset and duration of sensory and motor block, and duration of analgesia, for axillary brachial plexus block. METHODS: After institutional approval and informed consent had been obtained, 45 patients scheduled for forearm or hand surgery under axillary brachial plexus block were randomly allocated into two groups. The ropivacaine group received 40 ml of ropivacaine 7.5 mg/ml plus 2 ml of isotonic sodium chloride solution, and the tramadol group received 40 ml of ropivacaine 7.5 mg/ml plus 2 ml (100 mg) of tramadol. The onset and duration of sensory and motor block in the distribution of the musculocutaneous, radial, median and ulnar nerves, the duration of analgesia, the time to first pain medication, hemodynamics and side-effects were recorded. RESULTS: The addition of tramadol did not improve the speed of onset or increase the duration of sensory and motor block. The durations of analgesia were 631 +/- 33 min and 633 +/- 37 min (mean +/- standard deviation) in the ropivacaine and tramadol groups, respectively (P > 0.05). Hemodynamic parameters and side-effects did not differ between the groups. CONCLUSION: The addition of 100 mg of tramadol to 7.5 mg/ml of ropivacaine, for axillary brachial plexus block, does not prolong the duration of motor and sensory block and analgesia.

The role of antioxidant supplementation in occupational exposure to waste anaesthetic gases.

OBJECTIVES: Although the genotoxicity related to waste anaesthetic gases is controversial, a consistent number of observations have provided evidence for an increased level of DNA strand breaks. The goal of the research was to investigate this hypothesis and estimate the genoprotective role of antioxidant supplementation in technical anaesthesiology staff working in operating theatres. METHODS: Heparinized venous blood samples were collected from 17 exposed technical anaesthesiology staff (mean age 34.3 +/- 3.5 years) and non-exposed control group (mean age 32.2 +/- 3.4 years) and examined in the alkaline comet assay for DNA strand breakage. Vitamin E (300 mg/day) plus vitamin C (500 mg/day) were supplemented to the technical anaesthesiology staff for 12 weeks and blood samples were retaken and evaluated by comet assay. RESULTS: The DNA breakage observed in the lymphocytes of the technical anaesthesiology staff was 21.5 +/- 5.0, as calculated by total comet score (TCS). This score was significantly higher (P<0.001) than in the controls (8.6 +/- 4.7) before antioxidant treatment. Supplementation of vitamins E plus C significantly (P<0.01) reduced the mean TCS as 14.2 +/- 6.1. CONCLUSION: The results of our study indicate that occupational exposure to anaesthetic gases induces oxidative DNA damage. Supplementation of the diet for 12 weeks with vitamin C and vitamin E resulted in a significant decrease in the DNA damage.