The neuroprotective effect of mesenchymal stem cells in colistin-induced neurotoxicity.

Colistin is an effective antibiotic against multidrug-resistant gram-negative bacterial infections; however, neurotoxic effects are fundamental dose-limiting factors for this treatment. Stem cell therapy is a promising method for treating neuronal diseases. Multipotent mesenchymal stromal cells (MSC) represent a promising source for regenerative medicine. Identification of neuroprotective agents that can be co-administered with colistin has the potential to allow the clinical application of this essential drug. This study was conducted to assess the potential protective effects of MSC, against colistin-induced neurotoxicity, and the possible mechanisms underlying any effect. Forty adult female albino rats were randomly classified into four equal groups; the control group, the MSC-treated group (A single dose of 1 × 106/mL MSCs through the tail vein), the colistin-treated group (36 mg/kg/d colistin was given for 7 d) and the colistin and MSC treated group (36 mg/kg/d colistin was administered for 7 d, and 1 × 106/mL MSCs). Colistin administration significantly increased GFAP, NGF, Beclin-1, IL-6, and TNF-α immunreactivity intensity. MSC administration in colistin-treated rats partially restored each of these markers. Histopathological changes in brain tissues were also alleviated by MSC co-treatment. Our study reveals a critical role of inflammation, autophagy, and apoptosis in colistin-induced neurotoxicity and showed that they were markedly ameliorated by MSC co-administration. Therefore, MSC could represent a promising agent for prevention of colistin-induced neurotoxicity.

The effect of pulsed radiofrequency application on nerve healing after sciatic nerve anastomosis in rats.

The Effect of Pulsed Radiofrequency Application on Nerve Healing After Sciatic Nerve Anastomosis in Rats. In this study, we aimed to evaluate the histomorphological and functional effect of Pulsed Radiofrequency (PRF) application on regeneration after experimental nerve damage in rats. Forty Sprague-Dawley male rats were used in the study. Sciatic nerve incision was applied to all rats and then anastomosis was performed. Twenty rats were separated as the control group, and the remaining 20 rats underwent PRF every day at 42oC, for 120 seconds. The groups were divided into two further subgroups to be sacrificed on the 15th and 30th days. Tissue samples were obtained from all groups at 24 hours and 72 hours after the injury. Sections of sciatic nerve samples were stained with hematoxylin-eosin for light microscopic investigation and prepared for evaluation of ultrastructural changes with transmission electron microscopy. In the evaluation of axon numbers and diameters were seen that the 30th-day RF group had an increase compared to the control group. In the electron microscopic examination, it was observed that myelinated and unmyelinated nerve fiber sheaths had borders that are more regular in the RF group, the nucleus structures of schwann cells were better preserved, mitochondrial damage was less, and the extensions of fibroblast and collagen fibers were smoother than the control group. The findings suggested that PRF application has a positive contribution histologically on nerve healing in the early period after full-layer incision nerve injury anastomosis surgery.

Effects of dexmedetomidine and esmolol on otoacoustic emissions during controlled hypotensive anesthesia: randomized clinical trial.

PURPOSE: The aim of this study was to investigate the ability of esmolol and dexmedetomidine to achieve controlled hypotension on cochlea by measuring otoacoustic emission and stapedius reflex. METHODS: In this prospective, double-blind pilot study, patients scheduled for elective tympanoplasty, rhinoplasty and endoscopic sinus surgery operation were randomly assigned to two groups, and received either dexmedetomidine (n=23) or esmolol (n=24) during surgery to maintain a mean arterial blood pressure between 55 and 65 mmHg. Distortion product otoacoustic emission tests (DPOAE) were performed 24 hours before and after the operation and during surgery (in the 20th and 40th minutes of the operation). RESULTS: In the intra-group comparison, a statistically significant decrease was present at t20 (2,000 and 4,000 Hz frequency band) and t40 (1,000 and 1,500 Hz) according to the baseline value in the dexmedetomidine group (n=23); in the esmolol group (n=24), a statistically significant decrease (relative to the baseline value) was also detected at t20 and t40 for the 1,000 Hz frequency band. No damage was found on stapes reflexes with the infusion of these drugs. CONCLUSIONS: Infusion of dexmedetomidine and esmolol decreased DPOAE levels during the operations, but DPOAE levels returned to normal in the postoperative period, and had no effect on stapes reflexes. Studies with larger groups of patients are needed to confirm these results in tympanoplasty and other surgeries.

Addition of dexmedetomidine to bupivacaine in supraclavicular brachial plexus block.

PURPOSE: Research is ongoing to determine the lowest dose of local anesthetics in brachial plexus block that provides adequate anesthesia and postoperative analgesia and reduces complications related to local anesthetics. METHODS: Patients 18-65 years of age who underwent upper limb surgery and who received ultrasound-guided supraclavicular brachial plexus block at the Erciyes University Faculty of Medicine Hospital between February 2014 and January 2015 were included in the study (n=50). Supraclavicular brachial plexus blocks were performed on Group B cases by adding 30 ml 0.33% bupivacaine and on Group BD cases by adding 15 ml 0.33% bupivacaine and 1 µg / kg dexmedetomidine. Block success was evaluated by the onset and block duration of motor and sensory block and the duration of analgesia. RESULTS: The block success of Group B and Group BD was 92.6% and 89.3%, respectively (P = 1.000). Onset time of sensory block, degree of sensory block, duration of sensory block, onset time of motor block, degree of motor block and duration of motor block were similar in both groups in the intergroup comparison (P > 0.05). Duration of analgesia and the operative conditions of groups were similar (P > 0.05). CONCLUSIONS: In the implementation of ultrasound-guided supraclavicular brachial plexus block, block success, sensory and motor block and analgesia duration were similar for patients anaesthetized with 30 ml of bupivacaine in comparison with dexmedetomidine+bupivacaine (when the bupivacaine dose was reduced by 50% by the addition of the adjuvant).

Comparison of the myotoxic effects of levobupivacaine, bupivacaine, and ropivacaine: an electron microscopic study.

The aim of this study was to investigate the myotoxic effects of bupivacaine, ropivacaine, and levobupivacaine which were applied intramuscularly to rat skeletal muscle. Forty Wistar-Albino rats were divided into four groups. In the study, .5% bupivacaine (Group B), .5% ropivacaine (Group R), .5% levobupivacaine (Group L), or .9% normal saline (Group SF) was applied intramuscularly to the right gastrocnemius muscle of rats. The rats in each group were sacrificed on the second day after injection. Sections of muscle samples were stained with hematoxylin-eosin for light microscopic investigation and prepared for the evaluation of ultrastructural changes in the subcellular level with transmission electron microscopy. All three local anesthetic agents caused qualitatively similar skeletal muscle damage. The most observed muscle damage was in Group B, muscle damage of Group R was less than that of Group B, and the least damage was seen in Group L quantitatively. Electron microscopic examination of each group that caused cellular damage was qualitatively similar. The most subcellular damage was observed in the group receiving bupivacaine, less was seen in the ropivacaine group, and the least was observed in the levobupivacaine group. The results indicated that bupivacaine caused more myotoxic damage than the other two agents in the skeletal muscle of rats and that levobupivacaine caused less myotoxic damage than both bupivacaine and ropivacaine at the cell and tissue levels.

Sedation for paediatric transcatheter atrial septal defect closure: comparison of two sedation protocols.

AIM: This study aimed to compare the effects of dexmedetomidine-propofol and ketamine-propofol sedation on haemodynamic stability, immobility, and recovery time in children who underwent transcatheter closure of atrial septal defects. METHODS: In all, 46 children scheduled for transcatheter closure of atrial septal defects (n = 46) were included. The dexmedetomidine-propofol group (n = 23) received dexmedetomidine (1 µg/kg) and propofol (1 mg/kg) for induction, followed by dexmedetomidine (0.5 µg/kg/hour) and propofol (100 µg/kg/minute) for maintenance. The ketamine-propofol group (n = 23) received ketamine (1 mg/kg) and propofol (1 mg/kg) for induction, followed by ketamine (1 mg/kg) and propofol (100 µg/kg/minute) for maintenance. RESULTS: In all, 11 patients in the dexmedetomidine group (47.8%) and one patient (4.3%) in the ketamine group demonstrated a decrease ≥20% from the baseline in mean arterial pressure (p = 0.01). Heart rates decreased ≥20% from the baseline value in 10 patients (43.4%) in the dexmedetomidine group and three patients (13%) in the ketamine group (p = 0.047). Heart rate values were observed to be lower in the dexmedetomidine group throughout the procedure after the first 10 minutes. The number of patients requiring additional propofol was higher in the dexmedetomidine group (p = 0.01). The recovery times were similar in the two groups--15.86 ± 6.50 minutes in the dexmedetomidine group and 19.65 ± 8.19 minutes in the ketamine group; p = 0.09. CONCLUSION: The ketamine-propofol combination was less likely to induce haemodynamic instability, with no significant change in recovery times, compared with the dexmedetomidine-propofol combination. The ketamine-propofol combination provided good conditions for the intervention.

The effect of playing music and mother's voice to children on sedation level and requirement during pediatric magnetic resonance imaging.

BACKGROUND: Magnetic resonance imaging examinations frequently cause anxiety and fear in children. The objective of this study was to investigate the effects of listening to music sound, the mother's voice, and sound isolation on the depth of sedation and need for sedatives in pediatric patients who would undergo MRI. METHODS: Ninety pediatric patients aged 3 to 12 years who were planned for imaging in the MRI unit were randomly assigned to isolation group (Group I), musical sound group (Group II), and mother's voice group (Group III). We evaluated patients' anxiety and sedation levels via the Observer's Assessment of Alertness/Sedation (OAA/S) RESULTS: Heart rate, oxygen saturation, OAA/S, and Ramsey scores during the procedure were not significantly different among the groups (p>0.05). The mean amount of propofol and total propofol consumption was statistically lower in the mother's voice group than in the isolation and music sound groups (p<0.001). Mean propofol amount and total propofol consumption were not significantly different in isolation and music sound groups (p>0.05). No difference was found between the groups regarding the time it took for the patients' Modified Aldrete score to reach 9 (p>0.05). CONCLUSIONS: In pediatric patients, listening to the mother's voice during MRI decreased the total sedative requirement consumed without increasing the depth of sedation.

Is the addition of dexmedetomidine to a ketamine-propofol combination in pediatric cardiac catheterization sedation useful?

Pediatric patients undergoing cardiac catheterization usually need deep sedation. In this study, 60 children were randomly allocated to receive sedation with either a ketamine-propofol combination (KP group, n = 30) or a ketamine-propofol-dexmedetomidine combination (KPD group, n = 30). Both groups received 1 mg/kg of ketamine and 1 mg/kg of propofol for induction of sedation, and the KPD group received an additional 1 µg/kg of dexmedetomidine infusion during 5 min for induction of sedation and a maintenance infusion of 0.5 µg/kg/h. In both groups, 0.2 mg/kg of propofol was administered as a bolus to maintain a Ramsey sedation score (RSS) greater than 4 throughout the procedure. None of the patients in either group required intubation. In the KP group, one patient required mask ventilation. The chin-lift maneuver needed to be performed for eight patients in the KP group and one patient in the KPD group (p < 0.05). Adding dexmedetomidine to the ketamine-propofol combination decreased movement during the procedures. The heart rate in the KPD group was significantly lower after induction of sedation and throughout the procedure (p < 0.05). No significant differences in systolic blood pressure, diastolic blood pressure, or respiration rates were found between the two groups (p > 0.05). The mean recovery time was longer in the KP group (5.86 vs 3.13 min; p < 0.05). Adding dexmedetomidine to a ketamine-propofol combination led to a reduced need for airway intervention and to decreased movement during local anesthetic infiltration and throughout the procedure. The recovery time was shorter and hemodynamic stability good in the KPD group.

The effect of passive smoking on the laryngospasm rate in children sedated during the esophagogastroduodenoscopy.

OBJECTIVES: To investigate the rate of laryngospasm with sedation during the esophagogastroduodenoscopy (EGD) procedure in children exposed to passive smoking and to examine the frequency of complications due to laryngospasm. METHODS: A single-blind, prospective, observational study with a total of 518 patients evaluated according to the American Society of Anesthesiologists (ASA) physical status as classification I-II, aged between 1-18 years, and planned to undergo an EGD procedure, were included. Age, gender, weight, ASA assessment, exposure to smoking (the mother, the father, both parents were smokers, or not exposed to smoking), drug doses used in sedation, and anesthesia-related complications, such as cough, decrease in oxygen saturation, and laryngospasm were recorded. RESULTS: Of the 518 patients included in the study, 213 had no smoking exposure history. Oxygen saturation did not decrease below 90% in patients who did not have any smoking exposure. In addition, no laryngospasm was observed in this group. However, 4 (11.4%) of 31 patients whose mother only smoked, 10 (5.1%) of 187 child patients whose father only smoked, and 12 (16.4%) of 61 patients whose mother and father both smoked experienced laryngospasm during the procedure. CONCLUSION: The rate of cough, laryngospasm, and hypoxia development increased during the sedation carried out in the EGD procedure in children who were exposed to passive smoke.Clinicaltrial.gov ID: NCT03920046.

Clinical efficacy of ultrasound guided erector spinae plane block in patients undergoing microwave ablation.

OBJECTIVES: To compare the effect of pre-emptive erector spinae plane block (ESPB) applied before the procedure on opioid consumption during the procedure and analgesic demand and opioid consumption after the procedure. METHODS: American Society of Anesthesiologists Physical Status Classification (ASA) I-II, 30 patients, with liver tumor and planned for microwave ablation (MWA) treatment were included in the interventional radiology clinic, Erciyes University, Kayseri, Turkey, Turkey between 2021 and 2022. Patients were randomized either to the ESPB or control group. Ultrasound-guided ESPB block with 20 mL of 0.25% bupivacaine was performed preoperatively in the ESPB group patients, and the patients who was not performed the ESPB the control group. All the patients were administered 1 µg/kg fentanyl, 1-2 mg/kg propofol, and 1 mg/kg ketamine for sedation during the MWA procedure after standard monitoring. Total opioid consumption and numeric rating scale (NRS) scores for pain were recorded at 0, 20, 40, and 60 minutes, and at 2, 4, 6, 12, and 24 hours after the procedure. RESULTS: Total opioid consumption and total opioid amount during the procedure were statistically significantly lower in the ESPB group (p<0.001). Although all of the patients in the control group needed additional fentanyl throughout the procedure, only 5 patients in the ESPB group needed additional fentanyl (p<0.001). Post-procedure NRS score values were significantly lower in the ESPB group at 40 minutes, 60 minutes and 4 hours (p<0.05). Numeric rating scale values at other times were statistically similar (p>0.05) CONCLUSION: This study showed that ESPB provided effective preemptive analgesia during MWA procedures.

Efficacy of stem cell-based therapies for colistin-induced nephrotoxicity.

The increase in infections with multidrug resistant bacteria has forced to return to the use of colistin, antibiotic with known nephrotoxicity. Mesenchymal stem cells (MSCs) are being extensively investigated for their potential in regenerative medicine. This study aimed to investigate the possible protective mechanisms of the MSCs against kidney injury induced by colistin. Forty adult female albino rats were randomly classified into 4 equal groups; the control group, the MSC-treated group (a single dose of 1 ×106 /ml MSCs through the tail vein), the colistin-treated group (36 mg/kg/day colistin was given for 7 days), and the both colistin and MSC group (36 mg/kg/day colistin and 1 ×106 /ml MSCs). Main outcome measures were histopathological alterations, kidney malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT) and immunohistological autophagy evaluation. MSC repressed the progression of colistin-induced kidney injury as evidenced by the improvement of histopathological alterations and the substantial increase MDA, and decrease SOD and CAT in serum levels. Moreover, MSC resulted in a profound reduction in oxidative stress as manifested by decreased MDA and increased SOD in serum. Notably, MSC suppressed colistin-induced autophagy; it reduced renal levels of Beclin-1, P62 and LC3A/B. Furthermore, MSC decreased renal levels of eNOS. Lastly, MSC efficiently decreased expression of the TUNEL positive cell number. MSC confers protection against colistin-induced kidney injury by alleviating oxidative stress, nitric oxide synthase besides modulating reducing autophagy and apoptosis.

Myotoxic effects of levobupivacaine, bupivacaine and ropivacaine in a rat model.

AIM: The aim of this study is to histopathalogically compare the myotoxic effects of a single injection of levobupivacaine, bupivacaine and ropivacaine in rat skeletal muscle. MATERIALS AND METHODS: Rats received intramuscular injections of 0.5% bupivacaine (Group B), 0.5% ropivacaine (Group R), 0.5% levobupivacaine (Group L), or 0.9% normal saline (Group SF) (30 rats/group). At two, 10 and 20 days, 10 rats from each group were sacrificed and muscle samples were examined for myotoxic effects using hematoxylin-eosin staining under a light microscope. RESULTS: Muscle damage in Groups B, L and R was similar qualitatively. In samples taken two days after injection, the muscle damage in Group B was maximal [Damage score: 3.0 (2.0-3.0)], Group R had less damage than Group B [damage score: 2.0 (2.0-3.0)] and the damage in Group L was minimal [Damage score: 1.0 (1.0-2.0)]. In muscle samples taken 10 days after injection, there was no significant difference in muscle damage scores among Groups B, R and L. In muscle samples taken 20 days after injection, regeneration was complete, and muscle mass was histologically normal for each of the three groups (B, L and R). CONCLUSION: Levobupivacaine's myotoxic effect is qualitatively similar to that seen (and previously reported) with bupivacaine and ropivacaine. Levobupivacaine was found to be quantitatively less myotoxic than bupivacaine and ropivacaine after a single intramuscular injection, only two days after injection. Myonecrosis developed after a single intramuscular injection of local anesthetic but was completely regenerated by the 20th day after injection.

The comparison of the effects of dexmedetomidine and midazolam sedation on electroencephalography in pediatric patients with febrile convulsion.

BACKGROUND: When electroencephalogram (EEG) activity is recorded for diagnostic purposes, the effects of sedative drugs on EEG activity should be minimal. This study compares the sedative efficacy and EEG effects of dexmedetomidine and midazolam. SUBJECTS AND METHODS: EEG recordings of 60 pediatric subjects with a history of simple febrile convulsions were performed during physiologic sleep. All of these patients required sedation to obtain follow-up (control) EEGs. Subjects in Group D received 0.5 µg·kg(-1) of dexmedetomidine, and those in Group M received 0.1 mg·kg(-1) of midazolam. For rescue sedation, the same doses were repeated to maintain a Ramsey sedation score level of between 4 and 6. RESULTS: The mean doses that were required for sedation were 0.76 µg·kg(-1) of dexmedetomidine and 0.38 mg·kg(-1) of midazolam. Diastolic blood pressure and HR were lower in Group D than in Group M (P < 0.05). Hypoxia was observed in 11 (36.7%) subjects in Group M and none in Group D; this was statistically significant (P < 0.001). Frontal and parieto-occipital (PO) EEG frequencies were similar during physiologic sleep and dexmedetomidine sedation. However, EEG frequencies in these areas (P < 0.001) and PO EEG amplitude (P = 0.030) were greater during midazolam sedation than during physiologic sleep. CONCLUSIONS: Dexmedetomidine is a suitable agent to provide sedation for EEG recording in children. There is less change in EEG peak frequency and amplitude after dexmedetomidine than after midazolam sedation.

Comparison of preincisional infiltrated levobupivacaine and ropivacaine for acute postoperative pain relief after septorhinoplasty.

BACKGROUND: To maintain a high standard of patient care, it is essential to provide adequate pain management in patients who undergo nasal surgery. Levobupivacaine and ropivacaine are relatively new long-acting local anesthetics. OBJECTIVE: The aim of this study was to compare the analgesic effect and blood loss of preincisional levobupivacaine HCl 0.25% and ropivacaine HCl 0.375% in patients undergoing septorhinoplasty. METHODS: Sixty American Society of Anesthesiologists (ASA) I and II patients (18-55 years old) who were scheduled for elective open technique septorhinoplasty under general anesthesia were recruited for this study. The anesthetic technique was standardized for both groups. Preoperative and postoperative hemoglobin levels were recorded for all patients. Patients were assigned randomly to 1 of 2 study groups, and preincisional surgical field infiltration with 5 mL of 0.5% levobupivacaine plus 5 mL of 0.9% saline (group L; n = 30) or 5 mL of 0.75% ropivacaine plus 5 mL of 0.9% saline (group R; n = 30) was performed by the same surgeon. The degree of pain was measured by visual analogue scale (VAS) for pain and recorded at multiple time points in all patients after surgery. RESULTS: The analgesic effect at 2 hours in the postanesthesia care unit (PACU) and at 24 hours postoperatively did not differ significantly between the 2 local anesthetics (P > 0.05). Pain scores of patients decreased after the 24 hours in levobupivacaine group and ropivacaine group when compared with 0-minute VAS values, and this was statistically significant (P < 0.05). No significant difference was observed between groups with respect to the preoperative and postoperative hemoglobin (P = 0.767 and 0.824, respectively) values. CONCLUSIONS: Local tissue infiltration with 0.25% levobupivacaine or 0.375% ropivacaine is similarly effective in reducing the postoperative pain associated with septorhinoplasty.

A comparison of 1 minimum alveolar concentration desflurane and 1 minimum alveolar concentration isoflurane anesthesia in patients undergoing craniotomy for supratentorial lesions.

BACKGROUND: A critical point in craniotomy is during opening of the dura and the subsequent potential for cerebral edema. Use of desflurane in neurosurgery may be beneficial because it facilitates early postoperative neurologic evaluation; however, data on the effect of desflurane on intracranial pressure in humans are limited. Isoflurane has been used extensively in neurosurgical patients. OBJECTIVE: This study compared 1 minimum alveolar concentration (MAC) desflurane with 1 MAC isoflurane in facilitating hemodynamic stability, brain relaxation, and postoperative recovery characteristics in patients who underwent craniotomy for supratentorial lesions. METHODS: A total of 70 patients (aged 18-65 years), with American Society of Anesthesiologists (ASA) 1 or 2 physical status, who underwent craniotomy for supratentorial lesions, were enrolled in the study. For induction of anesthesia, fentanyl (2 µg/kg IV) and propofol (2 mg/kg IV) were administered. Endotracheal intubation was performed after administration of vecuronium (0.1 mg/kg IV) for total muscle relaxation. Before insertion of the skull pins, additional fentanyl (2 µg/kg IV) was administered. Patients were randomly allocated to 1 of 2 anesthetic regimens. For maintenance of anesthesia, 35 patients received 1 MAC of desflurane (group 1) and 35 patients received 1 MAC of isoflurane (group 2) within 50% oxygen in nitrous oxide. Intraoperatively, heart rate (HR) and mean arterial pressure (MAP) were measured and recorded before induction and 1 minute after induction, after endotracheal intubation, before skull pin insertion and 1 minute after skull pin insertion, before incision and 1 minute after incision, and before extubation and 1 minute after extubation. Also, HR and MAP were recorded at 30-minute intervals. Postoperatively, extubation time, eye opening time to verbal stimuli, orientation time, and time to reach an Aldrete postanesthetic recovery score of ≥8 were recorded. In addition, opioid consumption was calculated and recorded. Brain relaxation was evaluated according to a 4-step brain relaxation scoring scale. All outcomes of the study were assessed and recorded by an anesthesiologist blinded to the volatile anesthetic gases studied. RESULTS: No significant difference in HR was observed between the 2 groups. Intraoperative MAP values in group 1 were higher than in group 2 (P < 0.05). No significant difference was found between these groups in brain relaxation and opioid consumption. Extubation time, eye opening time to verbal stimuli, and time to reach an Aldrete score of ≥8 were found to be significantly shorter in patients in group 1 compared with patients in group 2 (P < 0.05). CONCLUSIONS: In patients who underwent craniotomy for supratentorial lesions, patients who received 1 MAC desflurane-based anesthesia had earlier postoperative cognitive recovery and postoperative neurologic examination compared with patients who received 1 MAC isoflurane-based anesthesia. The observed benefits of early recovery from anesthesia, however, should be considered with risks such as higher MAP in patients administered 1 MAC desflurane.

Comparison of the effects of ketamine or lidocaine on fentanyl-induced cough in patients undergoing surgery: A prospective, double-blind, randomized, placebo-controlled study.

BACKGROUND: Fentanyl-induced cough is common but has not been viewed as a serious anesthetic problem. However, the cough may be explosive at times, may require immediate intervention, and may be associated with undesirable increases in intracranial, intraocular, and intra-abdominal pressures. Prevention of fentanylinduced cough in such situations is of paramount importance. Ketamine, at concentrations achieved with standard clinical doses, has a direct relaxant effect on airway smooth muscle. OBJECTIVE: This study was designed to assess the effects of ketamine or lidocaine on fentanyl-induced cough. METHODS: This double-blind, randomized, placebo-controlled study was conducted at the Erciyes University Medical School, Kayseri, Turkey. Consecutive adult patients aged 18 to 65 years and classified as American Society of Anesthesiologists physical status I or II who were undergoing elective surgery with general anesthesia were enrolled. Patients were randomly allocated equally into 3 groups to receive lidocaine 1 mg/kg, ketamine 0.5 µg/kg, or placebo intravenously 1 minute before fentanyl administration. Following intravenous fentanyl (1.5 µg/kg over 2 seconds) injection, an observer, unaware of the type of medication given to the patients, recorded the number of episodes of coughing, if any. Any episode of cough was classified as coughing and graded by investigators blinded to treatment as mild (1-2 coughs), moderate (3-4), or severe (≥5). Blood pressure, heart rate, pulse oximetry oxygen saturation (SpO2), and adverse effects (AEs) were recorded. RESULTS: A total of 368 patients were approached for inclusion; 300 patients met the inclusion criteria and were enrolled in the study. No patients in the ketamine group had cough. The frequency of cough was significantly lower in the lidocaine (11/100 [11%]; P = 0.024) and ketamine (0/100; P = 0.001) groups compared with the placebo group (23/100 [23%]). The intensity of cough was significantly lower in the lidocaine (mild, 7/100 [7%]; moderate, 4/100 [4%]; P = 0.037) and ketamine (0/100; P < 0.001) groups compared with the placebo group (mild, 10/100 [10%]; moderate, 12/100 [12%]; severe, 1/100 [1%]). Severe cough (≥5) was observed in 1 patient in the placebo group. Incidence and intensity of cough were significantly decreased in the ketamine group compared with the lidocaine group (incidence, P = 0.001; intensity, P = 0.003). There were no significant differences between groups with respect to systolic blood pressure, diastolic blood pressure, heart rate, SpO2, and AEs. CONCLUSION: Intravenous ketamine (0.5 mg/kg) significantly reduced the reflex cough induced by fentanyl compared with lidocaine and placebo, and was well tolerated.

Effects of naloxone and flumazenil on antinociceptive action of acetaminophen in rats.

BACKGROUND: Studies of acetaminophen suggest that multiple nociceptive pathways are involved in the drug's analgesic action. OBJECTIVE: The purpose of this study was to determine whether naloxone and flumazenil were able to modify or antagonize the antinociceptive effect of acetaminophen in rats. METHODS: Adult albino Wistar rats were used in the study and randomly allocated to 1 of 4 groups. The acetaminophen group (A group) was administered IP saline and then 300 mg/kg IP acetaminophen 5 minutes thereafter. The acetaminophen + naloxone group (AN group) was pretreated with 1 mg/kg IP naloxone, followed by 300 mg/kg IP acetaminophen 5 minutes later. The acetaminophen + flumazenil group (AF group) was pretreated with 1 mg/kg IP flumazenil, followed by 300 mg/kg IP acetaminophen 5 minutes later. The control group received 2.5 mL IP saline, followed by an additional 2.5 mL IP injection of saline 5 minutes later. The paw-withdrawal latency period of the rats was assessed by an investigator blinded to treatment using the hot-plate test at 30, 45, 60, and 90 minutes after administration of acetaminophen. RESULTS: Thirty-two rats were evenly randomized by envelope method into 4 groups of 8 rats each. Baseline values for the A, AN, AF, and control groups were not significantly different (9.1 [2.3], 10.5 [2.7], 9.8 [3.0], and 8.9 [1.4] sec, respectively). In the AF group, flumazenil appeared to antagonize the analgesic effect exerted by the acetaminophen in the hot-plate test (30 min, 10.3 [3.7] sec; 45 min, 11.7 [5.1] sec; 60 min, 12.1 [5.1] sec; and 90 min, 12.2 [4.9] sec) and values were not significantly different from those obtained in the control group (30 min, 9.8 [2.2] sec; 45 min, 9.0 [1.6] sec; 60 min, 9.2 [1.6] sec; and 90 min, 8.5 [2.0] sec). In the AN group, naloxone did not significantly affect the values observed in the hot-plate test (30 min, 18.0 [4.5] sec; 45 min, 21.5 [7.8] sec; 60 min, 20.5 [5.9] sec; and 90 min, 22.3 [7.4] sec) and values at all time points were not significantly different from those obtained in the A group (30 min, 17.8 [7.6] sec; 45 min, 20.9 [6.9] sec; 60 min, 21.5 [7.3] sec; and 90 min, 23.8 [8.6] sec). All postbaseline values in the A and AN groups were significantly increased versus baseline and versus the control group values (all, P < 0.05). All postbaseline values in the A group were significantly greater than those in the AF group (all, P < 0.05). CONCLUSION: Flumazenil antagonized the analgesic effect exerted by acetaminophen, while naloxone had no significant effect on acetaminophen's antinociceptive action in this pain model in rats.

Comparison of 0.5% levobupivacaine, 0.5% bupivacaine, and 2% lidocaine for retrobulbar anesthesia in vitreoretinal surgery.

PURPOSE: The authors compared the efficacy of local anesthetics levobupivacaine, bupivacaine, and lidocaine for retrobulbar anesthesia in vitreoretinal surgery. METHODS: A total of 135 patients presenting for vitreoretinal surgery under local anesthesia were included in the study. Patients were randomly allocated to one of three groups. Group LB patients received 5 mL of 0.5% levobupivacaine, Group L patients received 5 mL of 2% lidocaine, and Group B patients received 5 mL of 0.5% bupivacaine for retrobulbar anesthesia via inferotemporal injection. Sensory and motor block durations were recorded. Intraoperative and postoperative pain was assessed by using verbal pain scala. Anesthesia efficiency, patient and surgeon satisfaction, and akinesia were assessed by using point scales. Hemodynamic data and adverse events were recorded. RESULTS: The demographic characteristics of patients, duration of surgery, and hemodynamic data in both groups were similar. The duration of motor and sensory block was longer in levobupivacaine and bupivacaine groups than lidocaine group. Pain on injection was found more frequent in Group L and Group B than Group LB and the difference between the Groups LB and B was significant (p<0.05). Surgeon and patient satisfaction were also higher and intraoperative pain was less in levobupivacaine group than lidocaine and bupivacaine groups. CONCLUSIONS: Levobupivacaine provides longer motor and sensory block duration and higher surgeon and patient satisfaction than lidocaine and bupivacaine when used for retrobulbar anesthesia in vitreoretinal surgery.

Comparison of the effects of dexmedetomidine versus fentanyl on airway reflexes and hemodynamic responses to tracheal extubation during rhinoplasty: A double-blind, randomized, controlled study.

BACKGROUND: Stimulation of various sites, from the nasal mucosa to the diaphragm, can evoke laryngospasm. To reduce airway reflexes, tracheal extubation should be performed while the patient is deeply anesthetized or with drugs that do not depress ventilation. However, tracheal extubation during rhinoplasty may be difficult because of the aspiration of blood and the possibility of laryngospasm. Dexmedetomidine and fentanyl both have sedative and analgesic effects, but dexmedetomidine has been reported to induce sedation without affecting respiratory status. OBJECTIVE: The aim of this study was to compare the effects of dexmedetomidine and fentanyl on airway reflexes and hemodynamic responses to tracheal extubation in patients undergoing rhinoplasty. METHODS: This double-blind, randomized, controlled study was conducted at the Erciyes University Medical Center, Kayseri, Turkey. Patients classified as American Society of Anesthesiologists physical status I or II who were undergoing elective rhinoplasty between January 2007 and June 2007 with general anesthesia were eligible for study entry. Using a sealed-envelope method, the patients were randomly divided into 2 groups (20 patients per group). Five minutes before extubation, patients received either dexmedetomidine 0.5 µg/kg in 100 mL of isotonic saline or fentanyl 1 µg/kg in 100 mL of isotonic saline intravenously. All patients were extubated by anesthesiologists who were blinded to the study drugs, and all were continuously monitored for 15 minutes after extubation. Heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), and oxygen saturation using pulse oximetry (SpO2) were recorded before anesthesia, after drug administration, after skin incision, at the completion of surgery, and 1, 5, and 10 minutes before and after tracheal extubation. Any prevalence of laryngospasm, bronchospasm, or desaturation was recorded. RESULTS: Forty patients (25 men, 15 women; mean [SD] age, 24.86 [7.43] years) were included in the study. Dexmedetomidine was associated with a significant increase in extubation quality compared with fentanyl, reflected in the prevalence of cough after extubation (85% [17/20] vs 30% [6/20] of patients, respectively; P = 0.001). There were no clinically significant decreases in HR, SBP, DBP, or SpO2 after extubation with dexmedetomidine or fentanyl. In the dexmedetomidine group, HR was not significantly increased after extubation; however, in the fentanyl group, HR was significantly increased compared with the preextubation values (all, P = 0.007). HR was significantly higher in the fentanyl group compared with the dexmedetomidine group at 1, 5, and 10 minutes after extubation (all, P = 0.003). Compared with preextubation values, SBP was significantly increased at 1 and 5 minutes after extubation in the dexmedetomidine group (both, P = 0.033) and at 1, 5, and 10 minutes after extubation in the fentanyl group (all, P = 0.033). The postoperative sedation scores and the extubation, awakening, and orientation times were not significantly different between the 2 groups. In the dexmedetomidine group, bradycardia (HR <45 beats/min) was observed in 2 patients and emesis was observed in 2 patients. In the fentanyl group, emesis was observed in 3 patients, bradycardia in 2 patients, vomiting in 1 patient, and shivering in 1 patient; vertigo was reported in 1 patient. There were no significant differences in the prevalence of adverse events between the 2 groups. CONCLUSION: The findings in the present study suggest that dexmedetomidine 0.5 µg/kg IV, administered before extubation, was more effective in attenuating airway reflex responses to tracheal extubation and maintaining hemodynamic stability without prolonging recovery compared with fentanyl 1 µg/kg IV in these patients undergoing rhinoplasty.

[Addition of dexmedetomidine to bupivacaine in ultrasonography-guided paravertebral blockade potentiates postoperative pain relief among patients undergoing thoracotomy]. / Adição de dexmedetomidina à bupivacaína em bloqueio paravertebral guiado por ultrassom potencializa o alívio da dor pós­operatória em pacientes submetidos à toracotomia.

BACKGROUND AND OBJECTIVE: Thoracic paravertebral blockade is an alternative regional technique for comforting post-thoracotomy pain, thereby decreasing opioid consumption, postoperative nausea and vomiting, dizziness, respiratory depression and health care costs. The objective of this study was to investigate the effects of bupivacaine and bupivacaine plus dexmedetomidine on postoperative pain score and analgesic consumption in thoracotomy patients who had undergone ultrasonography-guided paravertebral blockade. MATERIAL AND METHOD: 93 ASA I-II patients aged 18-65 years were included in the study and scheduled for thoracic surgery. Prior to anesthesia induction, the paravertebral blockade procedure was performed by an anesthetist with ultrasonography. Cases were randomly stratified into three groups. The paravertebral blockade procedure was performed with 20mL 0.5% bupivacaine injection in Group B (n=31) and 20mL 0.5% bupivacaine+1mL dexmedetomidine (100µg) injection in Group BD. Group C received postoperative i.v. morphine via patient-controlled analgesia without paravertebral blockade. Post-operative pain scores were recorded in the recovery room and post-operatively using a VAS. Hemodynamic parameters, adverse effects and morphine consumption were also recorded. RESULTS: No significant difference was determined between Group B and Group C regarding intra-operative adverse effects such as bradicardia and hypotension, while these adverse effects were significantly higher in Group BD (p=0.04). VAS scores with rest and upon movement were significantly lower in Group BD compared to Group C (p<0.001). Total morphine consumption was significantly lower in both Group B and Group BD in comparison with Group C (p<0.001). In Group BD, HR and MAP were lower, but this was not clinically significant (p<0.05). CONCLUSION: The addition of dexmedetomidine to bupivacaine lowers postoperative pain scores and morphine consumption in thoracotomy patients who receive ultrasonography guided paravertebral blockade.