Kamil Toker

The incidence and risk factors of difficult mask ventilation

PurposeThe ability to ventilate and oxygenate a patient using a bag-mask breathing system may be lifesaving in the case of failure of the initial intubation attempt. In this study, we aimed to determine the incidence of difficult mask ventilation (DMV) and to find preoperative risk factors for this procedure.MethodsBased on methods used for overcoming some difficulties with bag-mask ventilation (MV), classification has been made into four categories: easy MV, awkward MV, difficult MV, and impossible MV. A univariate analysis was performed to identify potential risk factors predicting DMV, followed by a stepwise forward binary logistic regression, and the odds ratio and 95% confidence interval were calculated.ResultsA total of 576 patients were studied. Incidence of easy MV, awkward MV, and difficult MV were found to be 75.5% (n = 435), 16.7% (n = 96), and 7.8% (n = 45), respectively. Height, weight, age, male gender, increased Mallampati class, history of snoring, lack of teeth, and beard were found to be DMV risk factors (P < 0.05). Using a multivariate analysis, Mallampati class 4, male, history of snoring, age, and weight were found to be significantly associated with DMV. Although the incidence of DMV in general was 7.8% (n = 45), the incidence of DMV among patients with difficult intubation (n = 123) was found to be 15.5% (n = 19).ConclusionsMallampati class 4, male patients, history of snoring, increasing age, and increasing weight were found to be risk factors for DMV in our study.

A new supraglottic airway device: LMA‐Supreme™, comparison with LMA‐Proseal™

Background and objective: The LMA‐Supreme™ (S‐LMA™) is a new supraglottic airway device that presents combined features of flexibility, curved structure and single use and a different cuff structure. The purpose of this study was to compare the oropharyngeal leak pressures (OLP) of LMA‐Proseal™ (P‐LMA™) and S‐LMA™.

Propofol-nitrous oxide versus sevoflurane-nitrous oxide for strabismus surgery in children

Vomiting is a common problem following strabismus surgery. We compared the effects of propofol‐N2O and sevoflurane‐N2O on the incidence of oculocardiac reflex and postoperative nausea and vomiting. Forty unpremedicated children, aged 3–15 years were randomly assigned to two groups of 20 patients. In group 1, anaesthesia was induced and maintained with propofol infusion(173 ± 41 μg·kg−1·min−1). In group 2, anaesthesia was induced with N2O (66%) in O2 and incremental sevoflurane via face mask and maintained with sevoflurane. Both groups received 66% N2O in O2 throughout surgery. The overall incidence of vomiting and antiemetic requirement in the first 24 h was significantly higher in sevoflurane‐N2O group than propofol‐N2O group (P< 0.05). The propofol‐N2O group had significantly more episodes of oculocardiac reflex than sevoflurane‐N2O group (P< 0.05). Propofol‐N2O anaesthesia results in a significantly lower incidence of postoperative vomiting, yet a significantly higher incidence of oculocardiac reflex.

Comparison of nerve stimulation vs. ultrasound-guided lateral sagittal infraclavicular block

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.

Prophylactic ondansetron reduces the incidence of intrathecal fentanyl-induced pruritus.

We investigated the effectiveness of prophylactic IV ondansetron in preventing intrathecal fentanyl-induced pruritus. One-hundred-fifty ASA status I–II patients undergoing spinal anesthesia with 7–10 mg of hyperbaric bupivacaine and 25 &mgr;g of fentanyl were randomized to receive ondansetron 8 mg IV or normal saline IV before the commencement of spinal anesthesia. Evaluations were performed every 15 min in the first hour after the injection of study drugs and at 1, 2, 3, 4, 5, and 6 h after the administration of the study drug. Statistical analysis was performed by using &khgr;2 tests and Student’s t-test, as appropriate. The incidence of pruritus was significantly more frequent in the placebo group compared with the ondansetron group (68% versus 39%) (P = 0.001). Time to pruritus was similar in both groups (placebo group, 55 ± 32 min versus ondansetron group, 50 ± 31 min). Duration of pruritus was also similar in both groups (placebo group, 98 ± 60 min versus ondansetron group, 103 ± 58 min). Ondansetron prophylaxis significantly reduced the incidence of intrathecal fentanyl-induced pruritus in patients undergoing surgery under bupivacaine spinal anesthesia.

Clonidine addition prolongs the duration of caudal analgesia.

Background:  In this study, using a dose‐ranging design, we examined the effects of clonidine with 0.125% bupivacaine on the duration of post‐operative analgesia in caudal anaesthesia in children.

Effects of adding magnesium to bupivacaine and fentanyl for spinal anesthesia in knee arthroscopy.

PurposeThe aim of the study was to investigate the effects of adding intrathecal magnesium sulfate 50 mg to low-dose bupivacaine-fentanyl on the spread, duration, regression of spinal block, and postoperative analgesia in patients undergoing knee arthroscopy.MethodsThis study was designed in a prospective, randomized, and double-blinded manner. Sixty American Society of Anesthesiologists (ASA) physical status I or II patients were randomly allocated to receive 50 mg magnesium sulfate (3 ml) or 3 ml of preservative-free 0.9% NaCl following 6 mg bupivacaine 0.5% plus 10 μg fentanyl intrathecally. Date were collected regarding the highest level of dermatomal sensory blockade, the time to reach this level from the time of injection of the spinal anesthetic, Bromage scale of motor blockade at the time of reaching maximum sensory level, time for regression of two segments in the maximum block height, time to L2 regression, time to ambulation, and postoperative analgesic consumption.ResultsThe addition of intrathecal magnesium (50 mg) to spinal anesthesia prolonged the time for regression of two segments in the maximum block height and time to L2 regression, but did not affect maximum sensory level or the time to reach the highest level of sensory block. Even though the mean times to complete recovery of motor function were similar in the two groups, time to ambulation was significantly longer in the magnesium group than in the saline group. Total analgesic consumption in the first 24 h was not decreased significantly with the addition of magnesium to spinal anesthesia, but the time to first analgesic requirement was prolonged significantly.ConclusionEven though the time to first analgesic requirement was prolonged significantly by magnesium, the addition of intrathecal magnesium sulfate to spinal anesthesia is not desirable in patients undergoing knee arthroscopy due to the prolonged time to ambulation and the lack of effect of magnesium on postoperative analgesic consumption.

Lateral sagittal infraclavicular block: clinical experience in 380 patients

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.

Tracheal intubation in patients with rigid collar immobilisation of the cervical spine: a comparison of Airtraq® and LMA CTrach™ devices*

The aim of this study was to evaluate the effectiveness of the Airtraq® and CTrach™ in lean patients with simulated cervical spine injury after application of a rigid cervical collar. Eighty‐six consenting adult patients of ASA physical status 1 or 2, who required elective tracheal intubation were included in this study in a randomised manner. Anaesthesia was induced using 1 μg.kg−1 fentanyl, 3 mg.kg−1 propofol and 0.6 mg.kg−1 rocuronium, following which a rigid cervical collar was applied. Comparison was then made between tracheal intubation techniques using either the AirTraq or CTrach device. The mean (SD) time to see the glottis was shorter with the Airtraq than the CTrach (11.9 (6.8) vs 37.6 (16.7)s, respectively; p < 0.001). The mean (SD) time taken for tracheal intubation was also shorter with the Airtraq than the CTrach (25.6 (13.5) and 66.3 (29.3)s, respectively; p < 0.001). There was less mucosal damage in the Airtraq group (p = 0.008). Our findings demonstrate that use of the Airtraq device shortened the tracheal intubation time and reduced the mucosal damage when compared with the CTrach in patients who require cervical spine immobilisation.

Comparison of laryngeal tube with laryngeal mask airway in anaesthetized and paralysed patients.

BACKGROUND AND OBJECTIVE The laryngeal mask has become a widely accepted alternative to endotracheal intubation and mask ventilation. The laryngeal tube is a relatively new supraglottic airway device for airway management. We compared the new version of the laryngeal tube with the laryngeal mask. METHODS In a randomized design, either a laryngeal tube (n = 66) or a laryngeal mask (n = 66) were inserted. Ease of insertion, oxygenation and ventilation, spirometry data and postoperative airway morbidity were determined. RESULTS After successful insertion, it was possible to maintain oxygenation and ventilation in all the patients. Insertion success rates after the first, second and third attempts were 84.8% (n = 56), 12.1% (n = 8) and 3% (n = 2) for the laryngeal tube compared with 56.1% (n = 37), 25.8% (n = 17) and 18.2% (n = 12) for the laryngeal mask (P = 0.001). There was no significant difference in peak airway pressure, and dynamic compliance between the groups (P > 0.05). Blood on the cuff after removal of the device was noted in one patient with the laryngeal tube and in 10 patients with the laryngeal mask. Six patients in the laryngeal mask group complained of hoarseness (P = 0.012). CONCLUSION With respect to clinical function, the new version of the laryngeal tube and the laryngeal mask are similar and either device can be used to establish a safe and effective airway in paralysed patients.Background and objective: We compared heart rate dynamics during surgical levels of propofol and sevoflurane anaesthesia in a highly standardized setting. Methods: We recorded electrocardiography from 24 anaesthetized healthy male subjects. In the first parallel part of the study, the subjects were anaesthetized either with sevoflurane (n = 8) or propofol (n = 8) targeted to match 1.0, 1.5 and 2.0 minimal alveolar concentration/effective concentration 50. In the second part, a separate group (n = 8) underwent four different anaesthetic regimens targeted to bispectral index 40: sevoflurane alone, sevoflurane + 70% nitrous oxide, propofol alone and propofol + 70% nitrous oxide. The electrocardiography data were analysed using conventional time and frequency domain methods, and the approximate entropy method, which estimates the complexity of the data. Results: The induction of anaesthesia was followed by an overall reduction of heart rate variability, evident in all frequency bands in the spectral analysis, and also in the time domain measures. Approximate entropy decreased at 1 effective concentration 50 with propofol and at 2 minimal alveolar concentration with sevoflurane. In the second part of the study, the time domain variables and high‐frequency spectral power were all similarly reduced by sevoflurane and propofol anaesthesia, with and without nitrous oxide. Approximate entropy tended to decrease during propofol anaesthesia. Conclusions: Hypnotic levels of sevoflurane and propofol anaesthesia suppressed the heart rate variability measured using conventional analysis methods. Deeper surgical levels of anaesthesia also reduce the complexity of heart rate variability.