Ayse Mizrak

Ultrasound-guided infraclavicular brachial plexus block enhances postoperative blood flow in arteriovenous fistulas

OBJECTIVE Brachial plexus block offers several advantages when creating vascular access for hemodialysis. However, no controlled studies have directly evaluated arteriovenous fistula (AVF) blood flow in patients anesthetized by this method. We compared the effects of ultrasound-guided, infraclavicular brachial plexus block and local infiltration anesthesia on blood flow in the radial artery and AVF during the early and late postoperative periods. METHODS Sixty patients were randomly assigned to an experimental group, which received infraclavicular brachial plexus block (IB), or to a control (C) group that received local infiltration anesthesia. Blood flow in the distal radial artery was measured before and after IB or infiltration anesthesia. AVF flow during the early and late postoperative period was evaluated using duplex ultrasound imaging. The rates of primary fistula failure were also compared. RESULTS After anesthesia, preoperative radial arterial flow was 56 ± 8.6 mL/min in group IB vs 40.7 ± 6.11 mL/min in group C (P < .0001). Blood flow in the fistula, measured in mL/min at 3 hours, 7 days, and 8 weeks postoperatively, was also greater in group 1B vs group C, respectively, at 69.6 ± 7.9 vs 44.8 ± 13.8 (P < .001), 210.6 ± 30.9 vs 129 ± 36.1 (P < .001), and 680.6 ± 96.7 vs 405.3 ± 76.2 (P < 0.001). CONCLUSION When used for AVF access surgery, infraclavicular brachial plexus block provides higher blood flow in the radial artery and AVF than is achieved with infiltration anesthesia.

Propofol/Dexmedetomidine and Propofol/Ketamine Combinations for Anesthesia in Pediatric Patients Undergoing Transcatheter Atrial Septal Defect Closure: A Prospective Randomized Study

BACKGROUND Children undergoing cardiac catheterization usually need general anesthesia or deep sedation. OBJECTIVE This study was performed to compare the effects of propofol/dexmedetomidine and propofol/ketamine combinations on recovery time and hemodynamic parameters in pediatric patients undergoing transcatheter atrial septal defect (ASD) closure. METHODS This was a prospective randomized study. Pediatric patients with ASD were randomly assigned into 2 groups to receive propofol/dexmedetomidine or propofol/ketamine. The dexmedetomidine group received an infusion over 10 minutes of dexmedetomidine 1 microg/kg and propofol 2.0 to 2.5 mg/kg bolus for induction, then an infusion of dexmedetomidine 0.5 microg/kg/h and propofol 4 to 6 mg/kg/h for maintenance. In the ketamine group, patients received the same dose of propofol and ketamine 1 mg/kg for induction and 0.5 mg/kg/h by infusion for maintenance. The procedure was performed using both fluoroscopy and transesophageal echocardiography. Hemodynamic data, respiratory rate, and oxygen saturation were recorded before and after induction, 1 and 5 minutes after intubation, every 10 minutes thereafter during the procedure, and after extubation by researchers blinded to the study drugs. Recovery time, the primary outcome, was evaluated by a modified Steward score; a score of >or=6 means that the patient is awake or responds to verbal stimuli, has purposeful motor activity, and coughs on command. The time to reach a modified Steward score of >or=6 was recorded. The secondary outcome was the effects on the hemodynamic variables. Creatine kinase muscle-brain subunit, myoglobin, cardiac troponin I, and brain natriuretic peptide were the biochemical variables measured. Patients were monitored for respiratory (changes in oxygen status) and hemodynamic adverse effects (heart rate changes, blood pressure changes) until the second hour in the intensive care unit after the operation was concluded. RESULTS Nine patients each were randomly assigned to propofol/dexmedetomidine and propofol/ketamine. The demographic and clinical parameters were not significantly different between groups. In the dexmedetomidine group, 5 of the patients were male, mean (SD) age was 12.5 (10.4) years, and mean weight was 40.8 (27.8) kg. In the ketamine group, 3 patients were male, mean age was 10.1 (4.5) years, and mean weight was 30.0 (15.2) kg. The recovery time was significantly longer in the ketamine group than in the dexmedetomidine group (10.5 [3.4] vs 5.7 [0.8] minutes; P = 0.01). Systolic and diastolic blood pressure values were not significantly different between groups in any study period. Heart rate values were significantly higher in the ketamine group at 5 minutes after intubation (106.6 vs 84.2 beats/min), 10 minutes (111.8 vs 87.4 beats/min) and 30 minutes (110.0 vs 89.6 beats/min) perioperatively, and after extubation (126.8 vs 92.2 beats/min) (all, P < 0.05). In the dexmedetomidine group, one patient experienced shivering and one reported nausea; in the ketamine group, one patient reported nausea. Neither respiratory depression nor severe hypotension (ie, >20% change over baseline or requiring intervention) was observed in any patient. One patient developed agitation in the ketamine group. CONCLUSIONS In this small study, both dexmedetomidine and ketamine in combination with propofol were well tolerated in these pediatric patients who required ASD closure. The recovery period was significantly shorter in the dexmedetomidine group.

Pretreatment with Dexmedetomidine or Thiopental Decreases Myoclonus after Etomidate: A Randomized, Double-Blind Controlled Trial

BACKGROUND Myoclonic movements are common problems during induction of anesthesia with etomidate. The aim of this study was to compare the effect of pretreatment with dexmedetomidine (0.5 microg/kg) and thiopental (1 mg/kg) on the incidence of etomidate-induced myoclonus and postoperative pain. MATERIALS AND METHODS A prospective double-blind study was conducted at a university hospital. Ninety patients (ASA physical status I-II) were randomly assigned to one of three groups: patients were pretreated with either dexmedetomidine (0.5 microg/kg), thiopental (1 mg/kg), or saline before induction of anesthesia with etomidate. One minute after the injection of study drugs, etomidate, 0.3 mg/kg was given. Myoclonus was assessed on a scale of 0 to 3. Recovery time, postoperative pain score, and hemodynamic variables were recorded during the intraoperative and postoperative period. Headache, nausea, vomiting, and coughing were noted during the study. RESULTS The incidence and the intensity of myoclonus was significantly lower in the dexmedetomidine and thiopental groups (34%, 36%) than in the control group (64%) (P<0.05). The postoperative pain score at 30 min in the thiopental group was significantly higher than in the dexmedetomidine and control groups (63%) (P<0.05). CONCLUSIONS We concluded that pretreatment with dexmedetomidine or thiopental is effective in reducing the incidence and severity of etomidate-induced myoclonic muscle movements and pretreatment with thiopental increases the postoperative pain.

Tramadol use for axillary brachial plexus blockade.

BACKGROUND We investigated the effects of tramadol added to the mixture of local anesthetic for axillary brachial plexus blockade (ABB) in patients to have undergone hand and forearm surgery. MATERIALS AND METHODS Forty patients from the ASA classification I and II, between 18 and 60 y of age, were included in this randomized double-blind study. Group C: levobupivacaine (150 mg) + lidocaine (200 mg) (n = 20), Group T: levobupivacaine (150 mg), + lidocaine (200 mg) + tramadol (100 mg) (n = 20). Intravenous midazolam of 0.02 mg/kg was given for premedication. ABB was performed with 42 mL mixture of local anesthetic, using peripheral nerve stimulator. The duration of onset of motor and sensory blockades was recorded. The postoperative first analgesic need, sedation, and satisfaction score and side effects were recorded. RESULTS There was no significant difference between the groups regarding intraoperative visual analog scale (VAS), hemodynamics, adverse effects, sedative and analgesic requirement, and the patient satisfaction. The development of motor block at the median nerve on the 5th min (P = 0.03) and at the ulnar nerve on 10th and 15th min in Group T were (P = 0.01, P = 0.03, respectively) considerably longer than that in Group C. CONCLUSIONS Adding 100 mg of tramadol to the combination of levobupivacaine and lidocaine during ABB could not provide an important clinical effect in patients undergoing hand and forearm surgery.

Dexmedetomidine use during strabismus surgery in agitated children.

Objective: We aimed to investigate the effects of dexmedetomidine premedication before intravenous infusion of ketamine in agitated children undergoing strabismus surgery. Subjects and Methods: We enrolled 60 agitated pediatric patients, aged 4.5–11 years. The patients were randomly allocated to one of two anesthesia regimens. Group D patients were premedicated with a single dose of intravenous dexmedetomidine 0.5 µg/kg whereas group P patients received a placebo. Patients in both groups were administered intravenous ketamine 1 mg/kg i.v. over 1 min followed by a continuous infusion of ketamine 1–3 mg/kg/h i.v. (n = 30). Patients were intubated after receiving fentanyl 1 µg/kg and rocuronium bromide 0.5 mg/kg. Results: 21 (70%) patients in group D did not show the oculocardiac reflex (OCR) versus 7 (23%) in group P (p = 0.0006). The preoperative and postoperative agitation scores (p = 0.0001 and p = 0.03, respectively), the score on the Faces Pain Scale during awakening [3.0 (interquartile range, IQR 2.0–4.0) in group D and 0.0 (IQR 1.0–2.25) in group P] (p = 0.001) and at the 60th postoperative minute [IQR 2.0 (1.5–3.0) in group D and 2.0 (IQR 1.5–3.0) in group P] (p = 0.004), sore throat (26.6% in group D and 60% in group P) (p = 0.01) and analgesic requirement (20% in group D and 53% in group P) (p = 0.01) in group P were significantly higher than in group D. The Ramsay Sedation Score (RSS) in group D was significantly higher than in group P during awakening [2.0 (2.0–2.0) in group D and 4.5 (4.0–5.0) in group P] (p = 0.0001). Conclusion: Dexmedetomidine premedication followed by intravenous infusion of ketamine was effective in decreasing OCR, agitation, pain, analgesic requirement in agitated children undergoing strabismus surgery.

Premedication with dexmedetomidine and midazolam attenuates agitation after electroconvulsive therapy.

PurposeThis study was designed to compare the effects of premedication with dexmedetomidine and midazolam on post-electroconvulsive therapy (ECT) agitation (which patients had experienced previously and had been resistant to treatment). In addition, we aimed to evaluate the duration of convulsion, the propofol requirement, the recovery time, and patients’ satisfaction during and after ECT.MethodsFifteen patients with depressive episodes of bipolar disorder and nonbipolar recurrent depression and patients who underwent a series of three consecutive ECT treatments were studied as a crossover design. In this double-blind and placebo-controlled study, patients were randomly allocated to receive either dexmedetomidine, 0.5 μg·kg−1 (group Dex), midazolam, 0.025 mg·kg−1 (group Dor), or saline (group C) in a total volume of 20 ml given intravenously 10 min before the induction of anesthesia. Propofol was administered until the patients did not respond to a verbal command.ResultsThe mean duration of convulsive activity was longer in group Dex than in group C and group Dor (P < 0.05). The total dose of propofol requirement in group Dor and group Dex was lower than that in group C (P < 0.05). Agitation scores in both groups Dor and Dex were significantly lower than scores in group C (P < 0.05) at 10 and 15 min after ECT.ConclusionPremedication with low-dose intravenous dexmedetomidine, 0.5 μg·kg−1 or midazolam, 0.025 mg·kg−1 before ECT may be useful in managing treatment-resistant agitation after ECT, without adverse effects.

The Effects of Preemptive Tramadol and Dexmedetomidine on Shivering During Arthroscopy

Background: Shivering, the rate of which in regional anesthesia is 39% is an undesired complication seen postoperatively. Aims: This study aims to compare the ability of preventing the shivering of preemptive tramadol and dexmedetomidine during the spinal anesthesia (SA). Methods: A total of 90 patients with American Society of Anesthesiologists physical status I-II, aged 18-60 years and undergoing elective arthroscopic surgery with SA were divided into three groups randomly. After spinal block, 100 mg tramadol in 100 ml saline was applied in group T- (n = 30) and 0.5 μg/kg dexmedetomidine in 100 ml saline was applied in group D- (n = 30) and 100 ml saline was administered in group P- (n = 30) in 10 min. The hemodynamics, oxygen saturation, tympanic temperature, shivering and sedation scores were evaluated and recorded intraoperatively and 45 min after a postoperative period. Results: In group T and D, shivering scores were significantly lower when compared with group P in the intraoperative 20th min (P = 0.01). Sedation scores in group D were significantly higher than the baseline values (P = 0.03) and values in group T and P (P = 0.04). Conclusions: Preemptive tramadol and dexmedetomidine are effective in preventing the shivering under SA. In addition, dexmedetomidine was superior in increasing the level of sedation which is sufficient to prevent the anxiety without any adverse effects.

Premedication With Dexmedetomidine Alone or Together With 0.5% Lidocaine for IVRA

BACKGROUND This study aimed to compare the effects of low and same dose of dexmedetomidine when added to lidocaine for intravenous regional anesthesia (IVRA) and when administered for premedication before IVRA. MATERIAL AND METHODS In this double blind study, 45 patients with ASA physical status I-II were scheduled to undergo carpal tunnel release as an outpatient procedure and were randomly divided into three groups. IVRA was performed with 40 mL of 0.5% lidocaine in the operating room. A single dose of dexmedetomidine 0.5 μg/kg and placebo (saline) solution in a total volume of 20 mL were administered intravenously to group P (n=15) and group S (n=15), respectively, before IVRA. 0.5 μg/kg of dexmedetomidine was added to lidocaine in group A (n=15) during IVRA. The onset and recovery time of sensory and motor block, intraoperative-postoperative visual analog scale (VAS) and Ramsay sedation scores (RSS), analgesic requirement, hemodynamic variables, and side effects were noted. RESULTS Significantly shortened sensory block onset and recovery time in group P and A, shortened motor block onset time in group P, and decreased intra-postoperative VAS scores and analgesic requirement in groups P and A were found. Intraoperative RSS in group P and postoperative RSS in groups P and A were higher than in group S. Intraoperative and postoperative heart rate and postoperative mean arterial blood pressure (MAP) of group P was significantly lower than groups A and group S, respectively. CONCLUSION Both addition of dexmedetomidine to lidocaine and premedication with dexmedetomidine for IVRA similarly improve quality of anesthesia and perioperative analgesia without important side effects.

Ketamine versus propofol for strabismus surgery in children

Purpose: To compare the effects of intravenous infusion of ketamine and propofol anesthesia in children undergoing strabismus surgery. Methods: Sixty pediatric patients aged 4–11 years were enrolled for the study. Patients in Group K were infused ketamine 1–3 mg/kg/hr (n = 30) and patients in Group P were infused with propofol 6–9 mg/kg/hr (n = 30). After giving fentanyl 1 μg/kg and rocuronium bromide 0.5 mg/kg, patients were intubated. Results: The consumption of anesthetics (P = 0.0001) and antiemetics (P = 0.004), the incidence of oculocardiac reflex (P = 0.02) in Group K were significantly lower than in Group P. The recovery time (P = 0.008), postoperative agitation score (P = 0.005), Face Pain Scale (P = 0.001), Ramsay Sedation Score (P = 0.01) during awakening and at postoperative 30th min (P = 0.02) in Group K were significantly lower than in Group P. The postoperative agitation score during awakening was significantly lower than the preoperative values in Group K (P = 0.0001). Conclusions: The infusion of ketamine is more advantageous than the infusion of propofol in children for use in strabismus surgery.

The Effects of Dexmedetomidine on Ischemia Reperfusion Injury in Patients Undergoing Arthroscopy Under Spinal Anesthesia

OBJECTIVE Ischemia and reperfusion injury due to tourniquet application during arthroscopy is a well known problem. This study aimed to compare the effects of dexmedetomidine and ketamine on hemodynamic and respiratory variables and on total anti-oxidant status (TAS), total oxidant status (TOS) and malondialdehyde (MDA) as markers of ischemia-reperfusion injury. MATERIALS AND METHODS This study was approved by a local ethics committee. The study was performed on patients undergoing arthroscopic operation under spinal anesthesia. Thirty patients were randomized into two groups: Group D (dexmedetomidine; n=15) and Group K (Ketamine; n=15). Spinal anesthesia at the L2-4 level was achieved using a 25G spinal needle with hyperbaric bupivacaine at a dose of 12-15 mg in all patients. In Group D, patients were sedated with dexmedetomidine at a dose of 0.3-0.5 μg/kg/h, while Group K received ketamine at a dose of 1-1.5 mg/kg/h. Hemodynamic parameters, oxygen saturation, Ramsey sedation scale (RSS), and TAS, TOS, and MDA levels were recorded. RESULTS Demographic parameters, TAS, TOS and MDA levels were similar between groups. In Group K, the TOS levels after tourniquet removal were significantly lower than at baseline and during the use of the tourniquet. Preoperative hemodynamic and respiratory variables were similar in both groups. Blood pressure values were decreased compared to baseline but these decreases were not statistically significant. CONCLUSION In patients undergoing arthroscopy under spinal anesthesia, dexmedetomidine had effects similar to ketamine, led to insignificant alterations in hemodynamic and respiratory variables during surgery and had comparable effects on ischemia-reperfusion injury. Thus, we think that dexmedetomidine can be a safe alternative to ketamine as an intraoperative sedative.