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.

Jugular Venous Catheterization: A Case of Knotting.

A 79-year-old woman, diagnosed for cancer of the ovary, had a central catheter that was placed with difficulty through the right internal jugular vein intraoperatively. After oophorectomy, it was realized that the catheter was knotted. Thus, the central venous catheter was removed successfully using a traction technique in the operating room. Central venous catheter use may result in various complications, although it has been used as an invasive method for hemodynamic monitoring and fluid and drug infusion. Here, we present catheter knotting in a case with solutions for this complication, under literature review.

Effect of dexmedetomidine on erythrocyte deformability during ischemia-reperfusion injury of liver in diabetic rats.

AIM: The aim of this study is to evaluate the effect of dexmedetomidine on erythrocyte deformability during IR injury of liver in diabetic rats. METHODS: Twenty- eight Wistar Albino rats were included in the study after a 4 week streptozocin (65 mg/kg) treatment to observe the existence of diabetes. The animals were randomly assigned to one of the four experimental groups: GroupC and DC (sham-control group): The abdomen was dissected with a median laparotomy and the liver was collected. GroupDIR: The liver was collected after IR following the abdominal median laparotomy. GroupDIRD: The liver was collected after IR following the abdominal median laparotomy and 30 min of infusion of dexmedetomidine 100 µg/kg ip The deformability measurements were performed in erythrocyte suspensions containing Htc 5% in PBS buffer. RESULTS: The deformability index was significantly increased in diabetic rats, however it was similar in the GroupC and DIRD. It was significantly increased in the GroupDIR when compared to the GroupC, DIRD and DC. The relative resistance was increased in IR models. CONCLUSION: Erythrocyte deformability was damaged in rats having diabetes and IR injury. This injury might lead to further problems in microcirculation. It was shown that dexmedetomidine may be useful in enhancing the adverse effects of this injury (Tab. 1, Fig. 2, Ref. 41).

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.