Hilal Ayoğlu

Effectiveness of dexmedetomidine in reducing bleeding during septoplasty and tympanoplasty operations.

STUDY OBJECTIVE To determine the effect of dexmedetomidine on intraoperative bleeding during septoplasty and tympanoplasty operations. DESIGN Randomized, placebo-controlled study. SETTING Univesity medical center. PATIENTS 80 ASA physical status I and II patients, aged 18 to 65 years, 40 of whom were scheduled for septoplasty and 40 to undergo tympanoplasty operations. INTERVENTIONS Patients undergoing septoplasty (S) and tympanoplasty (T) operations were randomly divided into 4 groups. Dexmedetomidine (D) was administered to Group SD and Group TD first as a bolus dose of one microg kg(-1), then intraoperative maintenance was supplied with dexmedetomidine 0.7 microg kg(-1) hour(-1). Groups S and T (controls) were given identical amounts of saline. If systolic blood pressure measurements are greater than 20% preoperative values, then fentanyl one microg kg(-1) was given. MEASUREMENTS Intraoperative blood loss was determined with suction volumes and gauze counting. Bleeding was rated according to a 6-point scale. Hemodynamic parameters and fentanyl administration were recorded. MAIN RESULTS Group SD had less bleeding and lower bleeding scores (P < 0.05). In addition, this group received less intraoperative fentanyl (P < 0.05). The only significant difference between Groups TD and T was the amount of intraoperative fentanyl given (35.4 +/- 58.8 vs 110.0 +/- 81.0 microg) (P < 0.05). CONCLUSION Dexmedetomidine reduces bleeding, bleeding scores, and intraoperative fentanyl consumption during general anesthesia in septoplasty operations.

Comparison of ephedrine and ketamine in prevention of injection pain and hypotension due to propofol induction.

Background and objective: This prospective, double‐blind, randomized, placebo‐controlled study compares the effects of ephedrine and ketamine on injection pain, and hypotension from propofol. Methods: After obtaining the approval of the Ethics Commitee, 75 patients (ASA I‐II) scheduled for elective operations with general anaesthesia were divided into three groups. Saline 2 mL (Group S, n = 25), ketamine 0.5 mg kg−1 (Group K, n = 25) or ephedrine 70 μg kg−1 (Group E, n = 25) were administered over 5 s after tourniquet application. After releasing the tourniquet, propofol 2 mg kg−1 was injected in 30 s. Pain was evaluated on a numerical scale (0‐10) where 0 represented no pain and 10 the most severe pain possible. Systolic, diastolic blood pressures and heart rates were recorded preoperatively, 1 min after propofol injection, before intubation and 1, 2 and 3 min after intubation in all patients. Results: The incidences of pain in Groups S, E and K were similar (84%, 80% and 72%, respectively). The mean pain score in Group K (2.1, SD 3.1) was significantly lower than those of Groups S and E (4.9, SD 2.6 and 4.6, SD 3.3, respectively) (P < 0.05). The systolic and diastolic blood pressure values in Group K (120 ± 27 mmHg) and Group E (123 ± 21 mmHg) before intubation were significantly higher than that of Group S (104 ± 25 mmHg) (P < 0.05). There was no significant difference between the mean heart rate values of the groups. Conclusions: Low dose ketamine or ephedrine pretreatment may prevent hypotension due to propofol induction. Despite the reduction in injection pain intensity after ketamine, the study drugs were found to be ineffective in lowering the injection pain incidence.

Effects of Fentanyl-lidocaine-propofol and Dexmedetomidine-lidocaine-propofol on Tracheal Intubation Without Use of Muscle Relaxants

The aim of this study was to compare the effects of fentanyl or dexmedetomidine when used in combination with propofol and lidocaine for tracheal intubation without using muscle relaxants. Sixty patients with American Society of Anesthesiologists stage I risk were randomized to receive 1 mg/kg dexmedetomidine (Group D, n = 30) or 2 mg/kg fentanyl (Group F, n = 30), both in combination with 1.5 mg/kg lidocaine and 3 mg/kg propofol. The requirement for intubation was determined based on mask ventilation capability, jaw motility, position of the vocal cords and the patients response to intubation and inflation of the endotracheal tube cuff. Systolic arterial pressure, mean arterial pressure, heart rate and peripheral oxygen saturation values were also recorded. Rate pressure products were calculated. Jaw relaxation, position of the vocal cords and patients response to intubation and inflation of the endotracheal tube cuff were significantly better in Group D than in Group F (p < 0.05). The intubation conditions were significantly more satisfactory in Group D than in Group F (p = 0.01). Heart rate was significantly lower in Group D than in Group F after the administration of the study drugs and intubation (p < 0.05). Mean arterial pressure was significantly lower in Group F than in Group D after propofol injection and at 3 and 5 minutes after intubation (p < 0.05). After intubation, the rate pressure product values were significantly lower in Group D than in Group F (p < 0.05). We conclude that endotracheal intubation was better with the dexmedetomidine–lidocaine–propofol combination than with the fentanyl–lidocaine–propofol combination. However, side effects such as bradycardia should be considered when using dexmedetomidine.

Does dexmedetomidine reduce the injection pain due to propofol and rocuronium

Background and objectives: This prospective, double‐blind, randomized, placebo‐controlled study was designed to determine the efficacy of dexmedetomidine compared with lidocaine in reducing the pain of propofol and rocuronium injection pain. Methods: One hundred and fifty patients, scheduled for elective surgery with general anaesthesia, were divided into five groups: saline (Group 1), dexmedetomidine 0.25 &mgr;g kg−1 (Group 2), lidocaine 0.5 mg kg−1 (Group 3), dexmedetomidine 0.25 &mgr;g kg−1 plus lidocaine 0.25 mg kg−1 (Group 4) or dexmedetomidine 0.25 &mgr;g kg−1 plus lidocaine 0.5 mg kg−1 (Group 5) were administered at a rate of 0.5 mL s−1 after tourniquet application. The occlusion was released after 1 min and 5 mL of propofol was injected over 20 s. Pain was evaluated by use of a 10‐point verbal analogue scale. Then, the rest of the induction dose of propofol, 3 mL of saline bolus and 0.6 mg kg−1 of rocuronium, was injected. The response to injection of rocuronium was assessed with a four‐point scale (0–3). Results: Groups 1 and 2 were found to have higher propofol injection pain scores than Groups 3, 4 and 5 (P < 0.05). When the study groups were compared according to the overall incidence of withdrawal movements due to rocuronium (⩾1 response) in Groups 1, 2, 3, 4 and 5, they were different (86.7%, 60%, 36.7%, 50% and 40%, respectively) (P < 0.05). Except Group 1, there was no significant difference between the groups according to incidence of withdrawal movement after rocuronium injection (P = 0.325). Conclusions: Pretreatment with dexmedetomidine is not effective in reducing injection pain of propofol, but may attenuate the hand withdrawal associated to rocuronium, as lidocaine does.

The effects of dexmedetomidine dosage on cerebral vasospasm in a rat subarachnoid haemorrhage model.

We investigated the effect of two different doses of dexmedetomidine on vasospasm in a rat model of subarachnoid haemorrhage (SAH). SAH was induced by injecting 0.3 mL blood into the cisterna magna in all rat groups except the control (Group C). At 1 hour and 24 hours after SAH, 5 microg/kg dexmedetomidine was given to group D5, and 10 microg/kg dexmedetomidine was given to group D10. No medication was administered to the haemorrhage group (Group H). Malondialdehyde (MDA) and paraoxonase (PON) levels were measured at 48 hours after SAH. Mean wall thickness (MWT), mean luminal diameter (MLD), and proliferating cell nuclear antigen (PCNA) expression of the basilar artery were evaluated. MDA levels and MWT were lower in the dexmedetomidine groups. The lowest MDA levels and MWT were found in Group D10. The MLD was lowest in Group H. PCNA expression was observed only in Group D10. We concluded that dexmedetomidine reduces oxidative stress and vasospasm following SAH in a dose-dependent manner.

The Analgesic Effect of Dexketoprofen When Added to Lidocaine for Intravenous Regional Anaesthesia: A Prospective, Randomized, Placebo-Controlled Study

This prospective, randomized, placebo-controlled study evaluated the effects of dexketoprofen as an adjunct to lidocaine in intravenous regional anaesthesia (IVRA) or as a supplemental intravenous (i.v.) analgesic. Patients scheduled for elective hand or forearm soft-tissue surgery were randomly divided into three groups. All 45 patients received 0.5% lidocaine as IVRA. Dexketoprofen was given either i.v. or added into the IVRA solution and the control group received an equal volume of saline both i.v. and as part of the IVRA. The times of sensory and motor block onset, recovery time and postoperative analgesic consumption were recorded. Compared with controls, the addition of dexketoprofen to the IVRA solution resulted in more rapid onset of sensory and motor block, longer recovery time, decreased intra- and postoperative pain scores and decreased paracetamol use. It is concluded that coadministration of dexketoprofen with lidocaine in IVRA improves anaesthetic block and decreases postoperative analgesic requirements.

Effects of acute carbon monoxide poisoning on the P-wave and QT interval dispersions

OBJECTIVE The aim of our study was to investigate atrial conduction and ventricular repolarization inhomogeneities using P-wave dispersion (Pwd) and QT dispersion (QTd) analyses in acute carbon monoxide (CO) poisoning. METHODS Sixty patients were retrospectively included in this case-controlled study. Thirty acute CO poisoning patients were assigned to the Group with acute CO poisoning (ACOP). Patients who did not have acute CO poisoning were assigned to the control group (Group C, n=30). Anthropometric measurement, body mass index, electrocardiogram (ECG) and serum electrolyte levels were recorded in all patients. Also, carboxyhemoglobin (COHb) levels were recorded in Group ACOP. Pwd, QT interval and QTd durations were measured. Corrected QT (QTc) and QTc dispersion (QTcd) intervals were determined with the Bazett formula. Independent samples t and Chi-square tests were used for statistical analysis. RESULTS No statistically significant difference was found between the age, gender distribution, anthropometric measurement, serum electrolytes, PR and QT durations between the groups. The Pwd (56.33 ± 17.11 msec vs 28.33 ± 11.16 msec, p=0.001) and QTd (63.33 ± 26.69 msec vs 42.16 ± 7.84 msec, p=0.001) were significantly longer in Group ACOP than in Group C. In addition, QTc and QTcd durations of Group ACOP were also found to be significantly longer than in Group C (p=0.001). CONCLUSION In our study, we found in ECG analyses of patients with acute CO poisoning that the Pwd, QTc and QTcd durations were significantly prolonged when compared with control group. For this reason, patients with acute CO poisoning need close attention because of arrhythmias, which can be related to increased QTcd and Pwd durations.

Effect of menstrual cycle on the injection pain due to propofol.

Background This prospective, double-blind and randomized study is designed to determine the effect of menstrual cycle on the injection pain of propofol. Methods Seventy-two patients scheduled for elective surgery under general anaesthesia were divided into two groups according to the phase of the menstrual cycle. Patients were at follicular phase (Pd 8–12) in Group F (n = 36) and luteal phase (Pd 20–24) in Group L (n = 36). Injection pain was evaluated with 10-point numeric rating scale after 25% of the total propofol dose was injected over 20 s. Results There were no significant differences in terms of patient characteristics (P > 0.05). The mean propofol pain score was found 1.81 ± 2.30 in Group F and 4.83 ± 3.09 in Group L. Group L was found to have higher propofol injection pain scores than Group F (P < 0.001). Conclusion We conclude that the menstrual phase changes the perception of pain due to propofol injection, which is higher in the lutheal phase. In clinical practice, the phases of the menstrual cycle may have a significant role on injection pain of propofol in woman.

Anesthesia induction with sevoflurane and propofol: evaluation of P-wave dispersion, QT and corrected QT intervals.

The present study compared the effects of anesthesia induction with sevoflurane and propofol on hemodynamics, P‐wave dispersion (Pwd), QT interval and corrected QT (QTc) interval. A total of 72 adult patients were included in this prospective study. All patients had control electrocardiograms (ECGs) before anesthesia induction. Anesthesia was induced with sevoflurane inhalation or intravenous propofol. Electrocardiography for all patients was performed during the 1st and 3rd minutes of induction, 3 minutes after administration of muscle relaxant, and at 5 minutes and 10 minutes after intubation. Pwd and QT intervals were measured on all ECGs. QTc intervals were determined using the Bazett formula. There was no significant difference in Pwd and QT and QTc intervals on control ECGs. In the sevoflurane group, except for control ECGs, Pwd and QTc interval on all ECGs were significantly longer than those in the propofol group (p < 0.05). We conclude that propofol should be used for anesthesia induction in patients with a predisposition to preoperative arrhythmias, and in those whose Pwd and QTc durations are prolonged on preoperative ECGs.

Dexmedetomidine did not reduce the effects of tourniquet-induced ischemia-reperfusion injury during general anesthesia

Ischemia reperfusion injury causes the release of free oxygen radicals. Free oxygen radicals initiate the production of toxic metabolites, such as malondialdehyde (MDA), through the lipid peroxidation of cellular membranes. Following lipid peroxidation, the antioxidant enzyme system is activated against reactive oxygen species (ROS) and attempts to protect cells from oxidative damage. There is a balance between the scavenging capacity of antioxidant enzymes and ROS. Because of this balance, the total antioxidant capacity (TAC) measurement is a sensitive indicator of the overall protective effects of the antioxidants. Alpha2 receptor agonists are effective in preventing hemodynamic reactions during extremity surgeries by preventing the release of catecholamines secondary to tourniquet application. They have also been shown to possess preventive effects in various ischemia‐reperfusion injury models. In our study, we examined the effects of dexmedetomidine on tourniquet‐induced ischemia‐reperfusion injury in lower extremity surgeries performed under general anesthesia. The effects of dexmedetomidine were measured with serum MDA and TAC levels. We studied 60 adult American Society of Anesthesiologists (ASA) physical status I or II patients undergoing one‐sided lower extremity surgery with tourniquet. The patients were randomly divided into two groups. Group D was administered a dexmedetomidine infusion at a rate of 0.1 μg/kg/minute−1 for 10 minutes prior to induction and then at 0.7 μg/kg/hour−1 until 10 minutes before the end of the operation. The control group (Group C) received a saline infusion of the same amount and for the same period of time. General anesthesia was induced with thiopental, fentanyl, and rocuronium and maintained with nitrous oxide and sevoflurane in both groups. Venous blood samples were obtained before the administration of the study drugs (basal) at 1 minute before tourniquet release and at 5 and 20 minutes after tourniquet release (ATR). In both groups, MDA levels decreased at 5 and 20 minutes ATR when compared with the basal values (p < 0.05). TAC levels decreased at 1 and 5 minutes ATR and then returned to basal values at 20 minutes ATR (p < 0.05). In reference to the prevention of lipid peroxidation in tourniquet‐induced ischemia‐reperfusion injury, the results from the two groups in our study showed that dexmedetomidine did not have an additional protective role during routine general anesthesia.