Sinan Gursoy

A comparison of sedation with dexmedetomidine or propofol during shockwave lithotripsy: a randomized controlled trial.

BACKGROUND:Dexmedetomidine, because it has both sedative and analgesic properties, may be suitable for conscious sedation during painful procedures. Extracorporeal shockwave lithotripsy (ESWL) is a minimal to mildly painful procedure that requires conscious sedation. We thus evaluated the utility of dexmedetomidine compared with propofol during an ESWL procedure. METHODS:Forty-six patients were randomly allocated into two groups to receive either dexmedetomidine or propofol for elective ESWL. Dexmedetomidine was infused at 6 &mgr;g · kg−1 · h−1 for 10 min followed by an infusion rate of 0.2 &mgr;g · kg−1 · h−1. Propofol was infused at 6 mg · kg−1 · h−1 for 10 min followed by an infusion of 2.4 mg · kg−1 · h−1. Fentanyl 1 &mgr;g/kg IV was given to all patients 10 min before ESWL. Pain intensity was evaluated with a visual analog scale at 5-min intervals during ESWL (10–35 min). Sedation was determined using the Observers Assessment of Alertness/Sedation. The Observers Assessment of Alertness/ Sedation scores and hemodynamic and respiratory variables were recorded regularly during ESWL (35 min) and up to 85 min after. RESULTS:Forty patients were evaluated. Visual analog scale values with dexmedetomidine were significantly lower than those with propofol only at the 25–35 min assessments (P < 0.05). During sedation, the respiratory rate with dexmedetomidine was significantly slower but Spo2 was significantly higher than with propofol (P < 0.05). Other clinical variables were similar (P > 0.05). CONCLUSION:A combination of dexmedetomidine with fentanyl can be used safely and effectively for sedation and analgesia during ESWL.

Effects of Adding Dexmedetomidine to Levobupivacaine in Axillary Brachial Plexus Block

BACKGROUND Although several studies have described effects of dexmedetomidine on peripheral nerve blocks, to date there is limited knowledge available on the impact of dexmedetomidine adjunct to levobupivacaine in axillary brachial plexus block. OBJECTIVE In this study, we aimed to investigate the effects of adding dexmedetomidine to levobupivacaine for an axillary brachial plexus block. METHODS A total of 64 patients of American Society of Anesthesiologists physical status I/II scheduled to undergo forearm and hand surgery, in which an axillary block was used, were enrolled. The patients were randomly divided into 2 groups: in group L patients (n = 32), an axillary block was performed with 39 mL levobupivacaine 5% plus 1 mL of isotonic sodium chloride. In group D patients (n = 32), an axillary block was performed with 39 mL levobupivacaine 5% and 1 mL dexmedetomidine 1 μg/kg(-1) plus isotonic sodium chloride. Demographic data, mean arterial pressure (MAP), heart rate (HR), peripheral oxygen saturation (Spo2), sensory and motor block onset times and block durations, time to first analgesic use, total analgesic need, intraoperative verbal analog scale, postoperative visual analog scale (VAS) data, and side effects were recorded for each patient. RESULTS There were no significant differences in patient and surgery characteristics between the 2 groups. Sensory block onset time was shorter in group D (P < 0.05). Sensory and motor block duration and time to first analgesic use were significantly longer in group D (P < 0.05), and the total need for analgesics was lower in group D (P < 0.05). Intraoperative 5- and 10-minute verbal analog scale values and postoperative VAS value at 12 hours were significantly lower in group D (P < 0.05). Intraoperative MAP and HR values, except at 5 minutes and postoperatively at 10 and 30 minutes and 1 and 2 hours, were significantly lower in group D (P < 0.01). Bradycardia, hypotension, hypoxemia, nausea, vomiting, and any other side effects were not seen in any patients. CONCLUSIONS It was concluded in our study that adding dexmedetomidine to axillary brachial plexus block shortens sensory block onset time, increases the sensory and motor block duration and time to first analgesic use, and decreases total analgesic use with no side effects. ClinicalTrials.gov identifier ISRCTN67622282.

Acute amitraz intoxication: retrospective analysis of 45 cases.

Objective: To present special clinical and laboratory features of 45 cases (44 adult cases) who were intoxicated through oral route. Design: Retrospective study. Setting: Intensive care unit (ICU) of a university hospital. Patients: Forty-five patients admitted to the ICU of Cumhuriyet University Hospital. Results: Forty-five patients between 4 and 97 years of age were evaluated. Intoxication was the result of a suicide attempt in 67% of cases and accidental in 33% of cases. Unconsciousness, nausea and vomiting were the common initial symptoms. The major clinical findings in the ICU were bradycardia, myosis, hypothermia, hyperglycemia, hypotension, coma and respiratory depression. Blood glucose level was increased in 64% of cases. No problem was noted in the patient or the fetus in a pregnant, 27-year-old patient, who was intoxicated with 10 mL of 12.5% amitraz. The length of stay in the ICU was between 2 and 15 days. None of the patients died. All patients were discharged without neurological sequela. Conclusion: The prognosis of amitraz intoxications through oral route is benign and results in complete healing; however, we suggest that these cases should be well monitored and followed-up in ICUs.

The Effects of Intravenous Ephedrine During Spinal Anesthesia for Cesarean Delivery: A Randomized Controlled Trial

We designed a randomized, double-blinded study to determine the efficacy and safety of 0.5 mg/kg intravenous ephedrine for the prevention of hypotension during spinal anesthesia for cesarean delivery. Patients were randomly allocated into two groups: ephedrine group (n=21) and control group (n=21). Intravenous preload of 15 mL/kg lactated Ringers solution was given. Shortly after the spinal injection, ephedrine 0.5 mg/kg or saline was injected intravenous for 60 sec. The mean of highest and lowest heart rate in the ephedrine group was higher than those of control group (P<0.05). There were significant lower incidences of hypotension and nausea and vomiting in the ephedrine group compared with the control group (8 [38.1%] vs. 18 [85.7%]); (4 [19%] vs. 12 [57.1%], respectively) (P<0.05). The first rescue ephedrine time in the ephedrine group was significantly longer (14.9±7.1 min vs. 7.9±5.4 min) than that of the control group (P<0.05). Neonatal outcome were similar between the study groups. These findings suggest, the prophylactic bolus dose of 0.5 mg/kg intravenous ephedrine given at the time of intrathecal block after a crystalloid fluid preload, plus rescue boluses reduce the incidence of hypotension.

Addition of dexmedetomidine or lornoxicam to prilocaine in intravenous regional anaesthesia for hand or forearm surgery: a randomized controlled study.

AbstractBackground and objectives: Intravenous regional anaesthesia (IVRA) is a simple and cost-effective technique that is ideally suited for surgery involving the distal arm. This study compared the effect of lornoxicam or dexmedetomidine in IVRA with prilocaine in patients who underwent hand or forearm surgery. Methods: This randomized, double-blind study enrolled 75 patients scheduled for hand or forearm surgery. IVRA was achieved with 2% prilocaine 3 mg/kg in the control group (n = 25), 2% prilocaine 3 mg/kg plus dexmedetomidine 0.5 μg/kg in the dexmedetomidine group (n = 25), and 2% prilocaine 3 mg/kg plus lornoxicam 8 mg in the lornoxicam group (n = 25). In all groups, 0.9% NaCl solution was added to make up a total volume of 40 mL. Sensory and motor block onset and recovery times, haemodynamic variables, visual analogue scale (VAS) pain and sedation scores, duration of analgesia, total analgesic consumption over 24 hours, adverse effects and quality of anaesthesia were recorded. Results: Sensory block onset was shorter and sensory block recovery time longer in the dexmedetomidine group compared with the lornoxicam and control groups (p < 0.05). Sensory and motor block recovery times and duration of analgesia for tourniquet were prolonged in the dexmedetomidine and lornoxicam groups compared with the control group (p < 0.05). Median VAS scores for tourniquet pain in the dexmedetomidine and lornoxicam groups were lower than that of the control group at 15 and 30 minutes (p < 0.05). Postoperatively, the duration of analgesia time was longer and median VAS scores were lower during the first 12 hours in the dexmedetomidine and lornoxicam groups compared with the control group (p < 0.05). Total analgesic consumption over 24 hours was lower in the dexmedetomidine and lornoxicam groups compared with the control group (p < 0.05). Anaesthesia quality as determined by the anaesthesiologist was better in the dexmedetomidine and lornoxicam group than in the control group (p < 0.05). Conclusions: Addition of dexmedetomidine or lornoxicam to prilocaine in IVRA decreased VAS pain scores, improved anaesthesia quality and decreased analgesic requirement. We suggest that addition of dexmedetomidine or lornoxicam at the doses used in this study to IVRA with prilocaine in this setting can be useful without causing adverse effects. No hypotension, bradycardia or hypoxia requiring treatment was seen in any of the patients. Addition of dexmedetomidine had a more potent effect, shortening sensory block onset time and prolonging sensory block recovery time more than lornoxicam.

The role of K(+) channels on the inhibitor effect of sevoflurane in pregnant rat myometrium.

UNLABELLED Volatile anesthetics and K(+) channel openers inhibit spontaneous contractions in myometrial smooth muscle. Volatile anesthetics modulate K(+) channel activity. We investigated the role of two K(+) channel blockers on the effect of sevoflurane in pregnant rat myometrium. Term pregnant rat uteri were excised, and cross-sectional myometrial strips were mounted for isometric force recording. Sevoflurane inhibited the amplitude and frequency of spontaneous myometrial contractions in a concentration-dependent manner. The maximal inhibition measured in amplitude and frequency of spontaneous myometrial contractions with sevoflurane (at 3 minimum alveolar anesthetic concentration) was 44.32% and 33.32% of control contractions, respectively. Tetraethylammonium (TEA) and glibenclamide, K(+) channel blockers, increased spontaneous myometrial contractions in a concentration-dependent manner. Sevoflurane responses were repeated at concentrations with no effect on spontaneous contractility of TEA, a Ca(2+)-activated K(+) channel blocker, and glibenclamide, an adenosine triphosphate-sensitive K(+) channel blocker, in myometrial strips. TEA (3.10(-4) M) caused a significant reduction in sevoflurane-induced inhibitor responses, but glibenclamide (10(-6) M) did not. Sevoflurane-induced maximal inhibition (at 3 minimum alveolar anesthetic concentration) on amplitude and frequency of spontaneous myometrial contractions in the presence of TEA (3.10(-4) M) was 31.85% and 22.33% of control contractions, respectively (P < 0.05). These results suggest that the in vitroapplication of sevoflurane inhibited the amplitude and frequency of spontaneous myometrial contractions in pregnant rats in a concentration-dependent manner. Such inhibition was reduced by TEA. The inhibition of myometrial smooth muscle induced by sevoflurane seems to be mediated, at least in part, via activation of Ca(2+)-activated K(+) channels, because inhibition was reduced by TEA. IMPLICATIONS In this study, we found that sevoflurane causes significantly decreased myometrial contractile activity in pregnant rats. The inhibition of myometrial smooth muscle induced by sevoflurane seems to be mediated, at least in part, via activation of Ca(2+)-activated K(+) channels, because inhibition was reduced by tetraethylammonium.

Thoracic paravertebral block for postoperative pain management in percutaneous nephrolithotomy patients: a randomized controlled clinical trial.

Objective: To investigate the effect of thoracic paravertebral block (PVB) on pain control and morphine consumption in percutaneous nephrolithotomy operations. Subjects and Methods: This randomized controlled clinical study was performed on 60 American Society of Anesthesiologists (ASA) I-II patients between the ages of 18 and 60 years who underwent percutaneous nephrolithotomy with approval of the ethical committee and written consent of the patients. Patients were randomly allocated into two groups: group P had 4 ml of 0.5% levobupivacaine injected at each of the T10, T11, and T12 paravertebral spaces and a standard PVB, and group C received 4 ml of 0.9% NaCl solution. All patients were given standard general anesthesia. The follow-up of saturation, heart rate, peripheral oxygen, and blood pressure values was recorded before induction, intraoperatively, and postoperatively. At postoperative 1, 2, 6, 12, and 24 h, the visual analog scale (VAS), Ramsey sedation score, respiratory rate, and 24-hour total morphine consumption were recorded. In addition, side effects and satisfaction of patients were recorded. Results: VAS scores and total morphine consumption were lower in group P than in group C: 2.3 vs. 4.3 and 22.3 vs. 43.2 mg, respectively (p < 0.05). The level of satisfaction was higher in group P than group C. Differences between groups in other parameters were not significant. Conclusions: Thoracic PVB with levobupivacaine provided a good postoperative analgesia and increased patient satisfaction for those who underwent percutaneous nephrolithotomy.

Vasorelaxant effect of opioid analgesics on the isolated human radial artery

Background and objective: Arterial grafts are prone to vasospasm. Opioid analgesics are commonly used in the perioperative course of cardiac surgical procedures. Therefore, we investigated the direct effects of morphine, meperidine, fentanyl and remifentanil on the human radial artery. Methods: Radial artery segments, obtained from 20 patients, were precontracted with phenylephrine. Using the organ bath technique, the endothelium‐independent vasodilatation was tested in vitro by addition of cumulative concentrations of morphine, meperidine, fentanyl and remifentanil in separate organ baths, in the presence or absence of naloxone. Indomethacin and NG‐nitro‐l‐arginine methyl ester was added to all organ bath in order to determine the effects of prostaglandins and nitric oxide, respectively. Results: Morphine (10−8–10−4mol L−1), meperidine (10−10–10−6mol L−1), fentanyl (10−10–10−6mol L−1) and remifentanil (10−8–10−4mol L−1) caused a concentration‐dependent vasorelaxation in the human being artery rings. The relaxations in the presence of naloxane did not change. The maximal relaxant effects of meperidine and fentanyl were significantly greater than those of morphine and remifentanil (P < 0.05). Conclusions: These findings indicate that morphine, meperidine, fentanyl and remifentanil produce concentration‐dependent and endothelium‐independent relaxations in human being radial artery rings. Meperidine and fentanyl are more potent relaxant agents than morphine and remifentanil in the human being radial artery in vitro.

Effects of alpha 2-adrenoceptor agonists dexmedetomidine and guanfacine on morphine analgesia and tolerance in rats

Abstract Background. Alpha 2 (α2)-adrenoceptor agonists may be useful for their potential to increase or prolong opioid analgesia while attenuating the development of opioid tolerance. The purpose of this study was to investigate the effects of dexmedetomidine and guanfacine (α2-adrenoceptor agonists) on morphine analgesia and tolerance in rats. Methods. Adult male Wistar albino rats weighing 195–205 g were used. To constitute morphine tolerance, animals received morphine (50 mg/kg) once daily for 3 days. After the last dose of morphine had been injected on day 4, morphine tolerance was evaluated by analgesia tests. The analgesic effects of dexmedetomidine (20 μg/kg), guanfacine (0.5 mg/kg), MK-467 (0.25 mg/kg), and morphine were estimated at 30-min intervals (0, 30, 60, 90, and 120 min) by tail-flick and hot-plate analgesia tests. Results. Our findings indicate that dexmedetomidine and guanfacine attenuated the expression of morphine tolerance. In addition, administration of dexmedetomidine with morphine increased morphine analgesia. On the contrary, data suggested that MK-467 (an α2-adrenoceptor antagonist) decreased morphine analgesia and increased morphine tolerance in analgesia tests. Conclusion. In conclusion, we observed that co-injection of dexmedetomidine or guanfacine with morphine attenuated the expression of tolerance to the analgesic effect of morphine and that dexmedetomidine enhanced the morphine analgesia.

Hypotensive anaesthesia with remifentanil combined with desflurane or isoflurane in tympanoplasty or endoscopic sinus surgery : a randomised, controlled trial

OBJECTIVE To compare the effect of remifentanil combined with desflurane or isoflurane on the quality of the operative field and surgical conditions, blood loss, and recovery during tympanoplasty or endoscopic sinus surgery. DESIGN Randomised, double-blinded clinical study. SUBJECTS Sixty-four patients were scheduled for elective tympanoplasty or endoscopic sinus surgery. The patients were randomly divided into two groups: desflurane or isoflurane. After anaesthesia induction, all patients received a continuous remifentanil infusion of 0.2-0.5 microg/kg/min until a mean arterial pressure of 65-75 mmHg was achieved. Heart rate and mean arterial pressure were recorded throughout anaesthesia. Blood loss was measured at the end of surgery. Achievement of a bloodless operative field was rated on a 100 mm visual analogue scale. Following completion of surgery, the time to extubation and to achievement of an Aldrete score of nine or more was recorded. RESULTS Sixty-three patients were evaluated. The total dose of remifentanil and the total blood loss were similar in both groups (p > 0.05). Time to extubation and to an Aldrete score of nine or more for the desflurane group was significantly less than for the isoflurane group (p 0.05). CONCLUSION Although desflurane and isoflurane both enabled good surgical conditions (in terms of quality of operative field) and convenient induction of hypotension for tympanoplasty and endoscopic sinus surgery, the recovery characteristics of desflurane were better than those of isoflurane. Therefore, desflurane may be preferable to isoflurane in such circumstances.