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Nateglinide (NAT) is an oral antihyperglycemic agent used for the treatment of noninsulin-dependent diabetes mellitus. We evaluated the NAT stability under various forced degradation tests (acidic, basic) and predicted the degradation mechanism of the NAT molecule in the gaseous phase and aqueous media. A first-order derivative spectrophotometric method was used for the identification of NAT and the products of its degradation. NAT appeared to be stable in acidic but not in basic media. A probable reaction path of the NAT molecule with OH radicals was analyzed. The optimized geometry was calculated with Gauss View 5. Subsequently, the lowest energy status was determined through geometric optimization using Gaussian 09 software. Aiming to determine the intermediates in the photocatalytic degradation mechanism, the geometric optimization of the molecule was realized using the density functional theory method. The activation energy for the probable reaction path was calculated, and their most stable state from the thermodynamic perspective was determined for the gaseous phase and aqueous media. The predicted mechanism was confirmed by comparison with the experimental results on simple structures reported in the literature. [ABSTRACT FROM AUTHOR]

Background: Carbon monoxide (CO) poisoning is associated with direct cardiovascular toxicity. QT dispersion (QTd) of the ECG is an indirect measure of heterogeneity of ventricular repolarization, which may contribute to ventricular arrhythmias. Our aim was to study QTd in patients with acute CO poisoning.Methods: CO intoxication was confirmed by arterial blood gas analysis. A control group consisted of age- and sex-matched individuals admitted to the hospital for unrelated clinical conditions. 12-lead ECG's were recorded on admission and repeated 1 week after discharge from the hospital. QT dispersion was defined as the difference between the greatest and the least QT intervals in any of the 12 leads.Results: Seventeen intoxicated patients, aged 5-46 years, had mean carboxyhemoglobin levels of 22.5 +/- 11.1%. On admission, corrected QT intervals of the intoxicated patients were significantly increased compared to the control group (431 +/- 18 ms vs. 404 +/- 28 ms, P = 0.008), but not the QT interval (358 +/- 25 ms vs. 345 +/- 20 ms, P = 0.17). Mean QTd and cQTd values (46 +/- 15 ms and 62 +/- 13 ms) of the intoxicated patients were significantly increased compared to the control group (17 +/- 4 ms and 33 +/- 15 ms, P < 0.0001 for both). Both QTd and cQTd decreased significantly after discharge from the hospital (P = 0.0001).Conclusion: Although QT dispersion increased in patients with CO poisoning, none of ECG's showed ventricular arrhythmia. Increased QTd in the absence of QT interval prolongation may have a lowered arrhythmogenic potential of CO poisoning. [ABSTRACT FROM AUTHOR]

Background: Depolarizing and non-depolarizing muscle relaxants possess many untoward side effects. In most patients endotracheal intubation may be performed with a propofol and alfentanil combination. The purpose of this study was to compare the effect on intraocular pressure (IOP) and haemodynamics of endotracheal (ET) intubation or laryngeal mask (LMA) insertion during total intravenous anaesthesia (TIVA) without the use of muscle relaxants.Methods: In a randomised study, 20 patients scheduled for elective orthopaedic surgery were assigned to two groups of 10 patients. Anaesthesia was induced with i.v. alfentanil 40 micrograms/kg and propofol 2.5 mg/kg. LMA insertion or ET intubation was achieved by the same anaesthesiologist. Airway score, insertion score, patient response and haemodynamics were recorded. IOP measurements were recorded before and after induction, 1 and 2 min after ET intubation or LMA insertion, and 1 and 2 min after extubation.Results: Mean arterial pressure and heart rate after insertion of the airway management devices was significantly higher than induction values in the ET group (P < 0.05), while during 2-3 min no significant changes were observed in LMA group. In all patients following propofol and alfentanil induction, IOP was significantly lower than preinduction values (P < 0.001). IOP following extubation was significantly higher than preinduction values in the ET group, but not in the LMA group (P < 0.001).Conclusion: During TIVA without the use of muscle relaxants neither LMA insertion nor ET intubation increased the IOP, but ET extubation did. [ABSTRACT FROM AUTHOR]

Background and Objective Supreme laryngeal mask airway ( S- LMA) has been improved in recent years, but comparative studies with a sizeable number of paediatric patients are limited in number. In this study, oropharyngeal leak pressures ( OLPs) were compared between S- LMA and Pro Seal laryngeal mask airway ( P- LMA) in paediatric patients. Methods After obtaining approval from the ethics committee and written informed consent from the relatives of the patients, 60 patients, from 9 months to 5 years of age and 10-20 kg in weight, who were recommended for elective surgery were included in this prospective and randomised study. The patients were assigned to the S- LMA and P- LMA groups. OLP, insertion times, success rates, ease of airway device placement, fibre optical assessment, success rates and insertion times of an orogastric tube ( OGT) were compared. Results P- LMA was placed successfully in all the patients. One patient was intubated in the S- LMA group. The outcomes of a total of 59 patients were analysed. The insertion times of the airway devices were shorter in the S- LMA group than in the P- LMA group ( S- LMA; 12.2 ± 2.9, P- LMA; 15.4 ± 3.7 s) ( P = 0.001). The first insertion attempts of airway device placement were similar. The OLPs were similar ( P- LMA; 17.2 ± 2.3, S- LMA; 16.4 ± 1.7 cm H2O). The fibre-optically determined anatomic position was better in the P- LMA group ( P = 0.02). The insertion time of the OGT was shorter with S- LMA than with P- LMA ( P = 0.01). Conclusion Our findings suggest that S- LMA has OLPs similar to those of P- LMA in paediatric patients and that S- LMA provides successful positive pressure ventilation. [ABSTRACT FROM AUTHOR]

Background: The objective of the study was to evaluate the influence of ultrasound (US) guidance alone vs. neurostimulation (NS) and US (NSUS) guidance techniques on block performance time and block success rate for the lateral sagittal infraclavicular block (LSIB). Methods: In a randomized and prospective manner, 110 adult patients scheduled for distal upper limb surgery were allocated to the US or the NSUS groups. In the US group, a local anesthetic (LA) was administered only with US guidance to produce a ‘U’-shaped distribution around the axillary artery. In the NSUS group, LA was administered under US guidance only after electrolocation of one of the median, ulnar or radial nerve-type responses. A total of 30 ml of LA (10 ml of levobupivacaine 5 mg/ml and 20 ml of lidocaine 20 mg/ml) was administered in both groups. Sensory block was tested at 10 min intervals for 30 min. Successful block was defined as analgesia or anesthesia of all five nerves distal to the elbow. Results: Block success rate was 94.5% in both groups. Block performance time was significantly shorter in the US than the NSUS group (157 ± 50 vs. 230 ± 104 s) ( P=0.000). Block onset time was similar in both groups (12.5 ± 4.8 in the US vs. 12.8 ± 5.4 min in the NSUS groups). There were two arterial punctures in the NSUS group. Conclusions: During LSIB performance US guidance alone produces block success rate identical to both US and NS guidance yet with a shorter block performance time. [ABSTRACT FROM AUTHOR]

Background: The objective of this study was to evaluate the influence of single vs. dual control during an ultrasound-guided lateral sagittal infraclavicular block on the efficacy of sensory block and the time of block onset. Methods: In a prospective manner, 60 adult patients scheduled for distal upper limb surgery were randomly allocated to single (Group S) or double stimulation (Group D) groups. A local anesthetic (LA) mixture of 20 ml of levobupivacaine 5 mg/ml and 20 ml of lidocaine 20 mg/ml with 5 μg/ml epinephrine (total 40 ml) was administered in both groups. In the Group S following a median, an ulnar or a radial nerve response, the entire LA was administered at a single site. In Group D 10 ml of LA was administered following the electrolocation of the musculocutaneous nerve and 30 ml LA was injected following median, ulnar or radial nerves. A successful block was defined as analgesia or anesthesia of all five nerves distal to the elbow. Sensory and motor blocks were tested at 5-min intervals for 30 min. Results: The block was successful in 27 patients in Group S and 28 patients in Group D. The time from starting the block until satisfactory anesthesia was significantly shorter in Group D than in Group S (19.3 vs. 23.2 min) ( P<0.05). Total sensory scores were significantly higher in the double stimulation group at 20 and 30 min after the block performance ( P<0.05). Conclusions: Although the block performance time was longer in the double stimulation group, block onset time and extent of anesthesia were more favorable in the double stimulation group. [ABSTRACT FROM AUTHOR]

A 25-year-old female developed permanent, fluctuating sensorineural hearing loss (SNHL), disabling vertigo, and tinnitus following an uneventful spinal anesthesia for cesarean section. At her first visit to the ear-nose-throat (ENT) department approximately 2 months postoperatively, pure-tone thresholds revealed profound SNHL on the right side whereas thresholds were within normal limits on the left side. The recruitment score (SISI) was 95% at 2000 Hz on the right side. Directional preponderance towards the right and the right canal paresis were evidenced by bithermal caloric testing. At follow ups the pure tone thresholds have shown some improvement, but fluctuating SNHL, disabling vertigo attacks, and tinnitus have remained. These findings imply a cochlear pathology causing endolymphatic hydrops possibly induced by lumbar puncture for spinal anesthesia. [ABSTRACT FROM AUTHOR]

Background: A nerve stimulation-guided lateral sagittal infraclavicular block (LSIB) has been proven to be an effective block. The purpose of this study was to evaluate whether the use of ultrasound (US) guidance would further improve the block quality of LSIB. Methods: In a prospective manner, 80 adult patients scheduled for hand, wrist and forearm surgery were randomly allocated to US or nerve stimulation (NS) groups. A needle was inserted into a sagittal plane, 20° dorsally, until muscle twitches were observed in synchrony with the stimulation. In the US group, the block was performed using the same puncture site but under ultrasonic guidance. The final position of the needle was verified with the use of a nerve stimulator. A local anesthetic mixture of 20 ml of levobupivacaine, 5 mg/ml and 20 ml of lidocaine and 20 mg/ml with 5 μg/ml epinephrine (total 40 ml) was administered in both groups. Results: The block was successful in 37 patients in the NS group and 38 patients in the US group. Block efficacy was better in the US group than the group NS in radial nerve distribution at 20 min ( P<0.05). In the US group, there was a slight tendency toward better block density in other nerve areas also but these differences were not significant. Vascular puncture was noted in three patients in the NS group and none in the US group. Conclusions: The block success rate was high and comparable in both groups. There was a trend toward improved block quality in the US group, although not significant. [ABSTRACT FROM AUTHOR]

Background: The purpose of this study was to evaluate the clinical utility and block success rate of ‘lateral sagittal infraclavicular block (LSIB)’ in a large-scale clinical study. Methods: Adult patients scheduled for hand, wrist and forearm surgery between March 2005 and June 2007 were prospectively included into the study. Using a nerve stimulator LSIB was performed. In the LSIB technique the puncture site is immediately adjacent to the most medial point of the coracoid process and the anterior surface of the clavicula. The needle is inserted caudally in a sagittal plane, 20° dorsally (downwards), until muscle twitches are observed in synchrony with the stimulation. A Local anesthetic mixture of either 20 ml bupivacaine 5 mg/ml or 20 ml of levobupivacaine 5 mg/ml and 20 ml of lidocaine 20 mg/ml with 5 μg/ml epinephrine (total volume 40 ml) was administered following electrolocation of the median, radial or ulnar nerve. Results: Three-hundred and eighty patients were included into the study. Block was successful in 341 (89.7%) patients without any need for local anesthetic supplementation. We had complete failure in 17 (4.5%) patients and these patients received general anesthesia. Twenty-two (5.8%) patients needed either infiltration of local anesthetic at the site of skin incision or supplementation of the block at the axilla. No other complications other than vascular punctures − 25 patients (6.6%) – were observed. Conclusions: LSIB provided a clinically acceptable success rate and our results are in agreement with other studies assessing this approach. [ABSTRACT FROM AUTHOR]

This randomized study was designed to compare discomfort caused by axillary or infraclavicular blocks in ambulatory patients. We identified which of the three block components, needle passes, local anesthetic (LA) injections, and electrical stimulations, is most painful and quantified pain intensity on a visual analog scale (VAS 0–100). We also assessed onset and quality of analgesia, adverse events and patients' acceptance. Eighty patients were studied. In axillary group – A, four LA injections were made after stimulating median, musculocutaneous, ulnar and radial nerves. In infraclavicular group – I, the whole LA volume was injected after stimulating median or ulnar or radial nerves. Patients were ready for surgery when they had analgesia/anesthesia distal to the elbow. Median intensity of block discomfort was 22 in A group and 10 in I group ( P < 0.01). There was no difference in distribution of the most painful block components between the groups. Block performance times were 4 min in I group and 7 min in A group ( P < 0.01). Block onset times were 18 min in A group and 20 min in I group (NS). There was one block failure in I group. Three patients in A group and five in I group required supplementary blocks (NS). Transient adverse events occurred in 14 A-group and two I-group patients ( P<0.01). Thirty-seven I-group and 33 A-group patients were satisfied with the block (NS). Infraclavicular block by single injection caused less discomfort and fewer adverse events than axillary block by multiple injections. Block effectiveness, onset time and patients' acceptance were similar. [ABSTRACT FROM AUTHOR]

The purpose of the study was to compare the effects of adding 50 μg of morphine, 25 μg of fentanyl or saline to 6 mg of hyperbaric bupivacaine on post-operative analgesia and time to urination in patients undergoing arthroscopic knee surgery under spinal anesthesia. In all groups satisfactory anesthesia was provided during the operation. There was a statistically significant difference between all the groups in times to voiding [Group BM 422 ± 161 min; Group BF 244 ± 163 min; Group BS 183 ± 54 min (mean ± SD)]. The incidence of pruritus was significantly greater in Group BM (80%) and BF (65%) in comparison with Group BS (no pruritus) (P < 0.05). The incidence of nausea was significantly increased in Group BM (35%) in comparison with Group BF (10%) and Group BS (P < 0.05). Analgesic consumption was significantly greater in Group BS in comparison with Groups BM and BF (P < 0.01). We conclude that during spinal anesthesia even mini-dose intrathecal morphine is not acceptable for outpatient surgery due to side-effects, especially severely prolonged time to urination. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented is presented in response to an article about effectiveness of infraclavicular block in children.