Mehmet Ozcan Ersoy

Effect of dexmedetomidine on bleeding during tympanoplasty or septorhinoplasty

Background and objective: The aim of this study was to evaluate the efficacy of dexmedetomidine, an &agr;2‐adrenoceptor agonist, on intraoperative bleeding, anaesthetic drug requirement and postoperative pain. Methods: Forty patients scheduled for elective tympanoplasty and septorhinoplasty operations under general anaesthesia were included in the study. The patients were randomly assigned to receive either a dexmedetomidine 1 &mgr;g kg−1 bolus 10 min before induction of anaesthesia plus 0.5 &mgr;g kg−1 h−1 infusions during maintenance or placebo. Mean arterial pressure was maintained between 60 and 80 mmHg. Perioperative mean arterial pressure, heart rate, time to extubation and time to awakening were recorded. Bleeding during surgery was assessed by the surgeon, blinded to the study drugs, both intraoperatively and postoperatively as a final personal opinion about the whole surgical process. Results: The heart rate and mean arterial pressure were significantly lower during induction, operation and extubation in the dexmedetomidine group (P < 0.05). Blood losses were lower in the dexmedetomidine group (P < 0.05). Propofol dose required for induction, and fentanyl and isoflurane consumption were significantly reduced in the dexmedetomidine group (P < 0.05). The total amounts of nitroglycerin and meperidine used were higher in the control group (P < 0.05). Conclusions: Dexmedetomidine decreased bleeding, postoperative analgesic requirements and intraoperative anaesthetic requirements and was associated with more stable haemodynamic responses to anaesthesia. We conclude that dexmedetomidine is a useful adjuvant to decrease bleeding when a bloodless surgical field is requested.

Effects of fentanyl on the incidence of emergence agitation in children receiving desflurane or sevoflurane anaesthesia.

Background and objective: In children, emergence agitation frequently complicates sevoflurane and desflurane anaesthesia. The effect of intravenous fentanyl 2.5 μg kg−1 was examined on the incidence of emergence agitation in children who received desflurane or sevoflurane after midazolam premedication and intravenous thiopental induction. Methods: One hundred and twenty children (2-7 yr) undergoing adenoidectomy or tonsillectomy, or both, were studied. All children were premedicated orally with midazolam 0.5 mg kg−1. After intravenous induction with thiopental and atracurium to facilitate endotracheal intubation, patients were randomly assigned to one of four groups: Patients in Groups 1 and 3 received physiological saline solution, whereas patients in Groups 2 and 4 received intravenous fentanyl 2.5 μg kg−1 during induction. Anaesthesia was maintained with sevoflurane in Groups 1 and 2 and with desflurane in Groups 3 and 4. After discontinuation of the volatile anaesthetic, the times to tracheal extubation and response to verbal stimuli (emergence time), and emergence behaviours were recorded. Results: The time to tracheal extubation was significantly shorter in Groups 3 (5.2 ± 1.7 min) and 4 (6.4 ± 2.1 min) than in Groups 1 (8.1 ± 2.1 min) (P = 0.0001 and 0.006, respectively) and 2 (8.8 ± 1.9 min) (P = 0.0001). The emergence time was significantly shorter in Group 3 (10.0 ± 3.9 min) than in Groups 1 (13.8 ± 4.9 min) (P = 0.017) and 2 (14.9 ± 4.1 min) (P = 0.003). The incidence rate of severe agitation was 13% in Groups 1 and 3, and 7 and 10% in Groups 2 and 4, respectively (P > 0.05). Conclusions: After midazolam premedication and intravenous induction of anaesthesia with thiopental, administration of intravenous fentanyl 2.5 μg kg−1 did not provide any clinically significant benefit on emergence agitation in children who receive sevoflurane or desflurane anaesthesia.

Propofol and erythropoietin antioxidant properties in rat brain injured tissue

So far, several treatment modalities have been attempted to brain protection in cases such as brain trauma, stroke or brain hemorrhage. However, a treatment method that the effect begins immediately and definitely helpful has not been discovered yet. In this study, we aimed to compare the effects of propofol and erythropoietin (Epo) on brain injury caused by oxidative stress and antioxidant properties of these agents after closed head injury (CHI) in rats. For this study, female Wistar Albino rats were divided into five groups: non-traumatic control group, trauma performed group CHI, trauma with propofol (100 mg/kg) intraperitoneally (i.p.), trauma with Epo (5000 U/kg) i.p. and trauma with propofol and Epo performed study groups. Twenty-four hours after CHI, rats were sacrificed and the brains were removed. Superoxide dismutase (SOD), catalase (CAT), xanthine oxidase (XO), nitric oxide (NO), and malondialdehyde (MDA) levels were measured in brain tissue. MDA and NO levels were decreased significantly in Groups Epo, Propofol and Epo+Propofol than Group CHI (p<0.01). XO activity was significantly lower in Group Epo than Group CHI (p<0.05). Epo and propofol decreased oxidative stress by decreasing MDA and NO level in brain tissue after CHI. However, combination of Epo and propofol has no significant beneficial advantage than Epo or propofol alone.

The effects of pre-operative dexmedetomidine infusion on hemodynamics in patients with pulmonary hypertension undergoing mitral valve replacement surgery

Background:  The aim of this study was to investigate the effects of pre‐operative dexmedetomidine infusion on hemodynamics in patients with pulmonary hypertension undergoing mitral valve replacement surgery.

The effects of intrathecal levobupivacaine and bupivacaine in the elderly

The objective of this study was to compare the block durations and haemodynamic effects associated with intrathecal levobupivacaine or bupivacaine in elderly patients undergoing transurethral prostate surgery. Eighty patients were prospectively randomised to receive plain 1.5 ml levobupivacaine 0.5% (group levobupivacaine) or 1.5 ml plain bupivacaine 0.5% (group bupivacaine) in combination with fentanyl 0.3 ml (15 μg) for spinal anaesthesia. The time to reach T10 and peak sensory block level, and to maximum motor block were significantly shorter in group bupivacaine compared to group levobupivacaine (p < 0.05). Peak sensory block level was also significantly higher in group bupivacaine. In group bupivacaine, mean arterial pressure was significantly lower than group levobupivacaine, starting from 10 min until 30 min after injection (p < 0.05). Hypotension and nausea were less common in group levobupivacaine than group bupivacaine (p < 0.05). Because of the better haemodynamic stability and fewer side‐effects associated with levobupivacaine, it may be preferred for spinal anaesthesia in elderly patients.

The effects of dexmedetomidine on liver ischemia–reperfusion injury in rats

BACKGROUND Ischemia-reperfusion (IR) injury of the liver may cause various types of damage to hepatic tissues. It can affect the prognosis of patients and the success of an operation. Dexmedetomidine is a selective α2 receptor agonist. We investigated whether dexmedetomidine provides protection against IR-induced liver injury in rats. METHODS Forty rats were divided equally into four groups. In group 1, the liver was manipulated after the laparotomy, and no occlusion of the vessels of the liver was performed. In group 2, once the abdomen was opened, 60 min of ischemia and 60 min of reperfusion were applied according to the segmental hepatic ischemia model. In group 3, 10 μg/kg of dexmedetomidine was injected into the peritoneal cavity 30 min before ischemia. In group 4, 100 μg/kg of dexmedetomidine was injected into the peritoneal cavity 30 min before ischemia. Further procedures in groups 3 and 4 were the same as those of group 2. After the experiment was completed, the rats were killed. Liver tissues were removed and stored until biochemical and histologic assessments were performed. RESULTS The malondialdehyde level in group 2 was higher than that of groups 1, 3, and 4 (P = 0.001, P = 0.000, and P = 0.000, respectively). Superoxide dismutase, catalase, and glutathione levels in group 2 were lower than those in group 1 (P = 0.001, P = 0.027, and P = 0.014, respectively). Superoxide dismutase and catalase levels in group 4 were higher than those in group 2 (P = 0.002 and P = 0.000, respectively). GSH levels in groups 3 and 4 were higher than those in group 2 (P = 0.049 and P = 0.006, respectively). A lower glutathione peroxidase level was detected in groups 2 and 3 than that in group 1 (P = 000). Group 4 demonstrated an increase in glutathione peroxidase levels compared with group 3 (P = 0.014). The histologic injury scores in groups 2-4 were higher than those in group 1 (P = 0.003, P = 0.002, and P = 0.001, respectively). However, the histologic injury scores were lower in groups 3 and 4 than those in group 2 (P = 0.003 and P = 0.002, respectively). CONCLUSIONS This study showed that dexmedetomidine may protect the liver against IR injury in rats.

Oral clonidine premedication does not reduce postoperative vomiting in children undergoing strabismus surgery

Background: We evaluated the effect of oral clonidine on postoperative vomiting (POV) in children undergoing strabismus surgery.

Comparison of propofol–alfentanil and propofol–remifentanil anaesthesia in percutaneous nephrolithotripsy

Background and objective: Percutaneous nephrolithotripsy (PCNL) is used for the fragmentation and removal of stones from the renal pelvis and renal calyceal systems. We compared the effects of propofol‐alfentanil or propofol‐remifentanil anaesthesia on haemodynamics, recovery characteristics and postoperative analgesic requirements during percutaneous nephrolithotripsy. Methods: Thirty non‐premedicated patients were randomly allocated to receive either propofol‐alfentanil (Group A) or propofol‐remifentanil (Group R). The loading dose of the study drug was administered over 60 s (alfentanil 10 μg kg−1 or remifentanil 1 μg kg−1) followed by a continuous infusion (alfentanil 15 μg kg−1 h−1 or remifentanil 0.15 μg kg−1 min−1). Propofol was administered until loss of consciousness and maintained with a continuous infusion of 75 μg kg−1 min−1 in both groups. Atracurium was given for endotracheal intubation at a dose of 0.5 mg kg−1 and maintained with a continuous infusion of 0.4 mg kg−1 h−1. Mean arterial pressure heart rate, the total amount of propofol, time of recovery of spontaneous ventilation, extubation and eye opening in response to verbal stimulus and analgesic requirement were recorded. Results: In Group A, mean arterial pressure was higher at the first minute in the prone position, and during skin incision and lithotripsy, and heart rate was higher during skin incision and lithotripsy when compared with Group R (P < 0.05). The total amount of propofol did not differ between groups. Time of recovery of spontaneous ventilation, extubation and eye opening were significantly shorter in Group R than Group A (P < 0.05). Conclusions: Both propofol‐remifentanil and propofol‐alfentanil anaesthesia provided stable haemodynamics during percutaneous nephrolithotripsy, whereas propofol‐remifentanil allowed earlier extubation.

The effects of cognitive impairment on anaesthetic requirement in the elderly.

Context Patients with dementia have a lower bispectral index score (BIS) when awake than age-matched healthy controls. Objectives The primary aim was to compare the BIS and the dose of propofol required for induction in patients suffering from cognitive impairment with that in those who had normal cognitive function. This study also evaluated the effects of cognitive impairment in the elderly on anaesthetic agent consumption during surgery and on emergence from anaesthesia. Design and setting This randomised controlled study was carried out in a university hospital. Patients over 65 years of age, ASA I-II and scheduled for elective orthopaedic procedures were allocated to one of two groups. Interventions Patients (n = 92) were allocated according to their Mini Mental State Examination score: 25 or higher (group 1) or 21 or less (group 2). All patients received propofol 0.5 mg kg−1 following the commencement of a remifentanil infusion at 0.5 &mgr;g kg−1 min−1. After incremental doses of propofol up to loss of consciousness, a propofol infusion was started at 75 &mgr;g kg−1 min−1. Propofol and remifentanil infusion doses were adjusted to keep the BIS value between 45 and 60 during surgery. Main outcome measure MMSE score was evaluated 24 h before and after surgery. The anaesthetic consumption, mean arterial pressure, HR and BIS values of the patients were recorded. Results Before surgery, mean Mini Mental State Examination scores were 26.8 ± 1.6 and 16.6 ± 4.2 in group 1 and 2, respectively. These returned to baseline value 24 h after surgery in group 1 (26.6 ± 1.5) and group 2 (15.6 ± 4.3). Before induction, four of 45 patients (8.9%) in group 1 had a BIS value less than 93 compared with 13 of 47 (27.7%) in group 2 (P = 0.02). The mean BIS value was significantly lower in group 2 than in group 1 before induction, during loss of consciousness, 3 and 5 min after discontinuation of the anaesthetic agents and before extubation (P < 0.05). The induction dose of propofol was lower in group 2 than in group 1 (P = 0.02). The eye opening time was significantly longer in group 2 than in group 1 (P = 0.03). Conclusion The baseline BIS value was lower in patients with cognitive impairment than in those with normal cognitive function. The former received less propofol during induction and eye opening time was longer. On the basis of our findings from the recovery period, we suggest that the recommended target BIS value for adequate anaesthesia in the general population is inappropriate for patients with cognitive impairment.

Dexmedetomidine blunts acute hyperdynamic responses to electroconvulsive therapy without altering seizure duration

Background: This study was designed to evaluate the effect of dexmedetomidine on the acute hyperdynamic response, duration of seizure activity and recovery times in patients undergoing electroconvulsive therapy (ECT).