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Biomedical subjects

B Gunaydin

Publications and source records attributed to B Gunaydin.

6 recordsLinked to original sources
PubMed2006

Prevention strategy for post dural puncture headache.

We report the anesthetic management of a parturient after an unintentional dural puncture while performing epidural anaesthesia for caesarean section and the strategy to prevent postdural puncture headache (PDPH). We injected the cerebrospinal fluid (CSF) back into the subarachnoid space and then administered intrathecal 1.5 mL 0.5% hyperbaric bupivacaine and fentanyl 20 microg to maintain CSF volume via epidural needle. The epidural catheter was inserted following re-identification of the epidural space for possible epidural top-up requirement and postoperative pain relief. After adding 3 mL of 0.5% isobaric bupivacaine via epidural catheter, sensory block level reached at T4 bilaterally. No PDPH was observed.

Adult↗
PubMed2001

Interaction of lidocaine with reactive oxygen and nitrogen species.

BACKGROUND AND OBJECTIVE: To investigate the ability of lidocaine to inhibit reactive oxygen and/or nitrogen species generation by either human leukocytes or cell-free systems via luminol- and lucigenin-enhanced chemiluminescence. METHODS: Venous blood was obtained from healthy volunteers and leukocytes were isolated, from which chemiluminescence was generated. Also, chemiluminescence, induced by H(2)O(2), HOCl, peroxynitrite or ferrous iron, was generated in cell-free systems. RESULTS: Lidocaine produced a concentration-dependent inhibition in chemiluminescence generated by leukocytes (92 +/- 1%, 1 mM). In cell-free experiments, lidocaine (1 mM) markedly inhibited chemiluminescence of xanthine-xanthine oxidase (24 +/- 3%), while it slightly suppressed hypochlorous acid-induced chemiluminescence (9 +/- 2%). Peroxynitrite-induced luminol- and lucigenin-enhanced chemiluminescence were also inhibited by lidocaine at 1 mM (19 +/- 3% and 48 +/- 8%, respectively). Lidocaine did not affect chemiluminescence generated by FeSO(4). However, lidocaine produced a biphasic effect on H(2)O(2)-induced chemiluminescence (37 +/- 5% inhibition at 0.01 mM and 61 +/- 17% activation at 1 mM). CONCLUSIONS: Lidocaine can elicit direct scavenging activity at high concentrations that might be important at or near the site of injection in local anaesthetic use.

Acridines↗
PubMed2001

Seasonal variation in the effect of a fixed dose of heparin on activated clotting time in patients prepared for open-heart surgery.

We investigated the effect of an injected bolus of 5 mg kg(-1) heparin at one circadian stage (08:30 to 11:00) on blood coagulation during different months of the year. Activated clotting times (ACTs) were assessed before and 5 min after heparin dosing to ensure extracorporeal circulation during open-heart surgery. The ACT data of 1083 presumably day-active Turkish patients (816 men and 267 women, mostly older than 46 years) who underwent coronary bypass surgery between 08:30 and 11:00 in the years from 1994 to 1997 were analyzed for annual rhythmicity. The ACT values obtained just before and 5 min after heparinization were subjected to cosinor analysis using a 365.25-day period to assess seasonality in basal ACT level and heparin effect. A small-amplitude annual rhythm with a wintertime peak was documented in the morning ACT in the group of 1083 patients. Rhythms of similar magnitude and staging were also detected in heparin effect on ACT in the 1083 patients and in subgroups categorized by gender. Circannual rhythmicity in the heparin effect on ACT was also documented in the elderly (> or = 45 years old), but not young (18-45 years old) patients. The annual mean effect of heparin on the ACT was statistically significantly greater in younger than older patients. The relatively low-amplitude circannual rhythm in heparin effect on ACT (approximately 10% of the annual mean) is not viewed as being meaningful in patient preparation for bypass surgery for the 5 mg kg(-1) level of heparin dose.

Adolescent↗
PubMed1998

Cerebral hypoperfusion after cardiac surgery and anesthetic strategies: a comparative study with high dose fentanyl and barbiturate anesthesia.

BACKGROUND: Postoperative delirium is a common sequel of cardiopulmonary bypass that is hard to diagnose correctly, difficult to predict and almost impossible to prevent and to treat. The aim of this study is to evaluate the frequency of postoperative cognitive disorders and cerebral hypoperfusion in patients receiving either high dose fentanyl or thiopentone anesthesia in cardiac surgery. METHODS: 50 unpremedicated patients, Class IIb-NYHA (25 patients in each group suffering from single critical LAD disease) undergoing elective coronary artery bypass grafting surgery were randomly allocated into two groups either to receive fentanyl 50 microg/kg with diazepam 0.1 mg/kg (Group 1) or thiopentone 7 mg/kg (Group 2) for the induction of anesthesia. Anesthesia was maintained with fentanyl 2 microg/kg/hr and diazepam 0.05 mg/kg/hr infusion in Group 1 throughout the procedure. In Group 2, it was maintained with enflurane 0.7-1.5% before and after cardiopulmonary bypass (CPB) and with thiopentone 3 mg/kg/hr infusion during CPB. Neuropsychiatric evaluation (STAI-T, min mental state examination-MMSE and Zung tests), EEG and SPECT rCBF (Single Photon Emission Computed Tomography Regional Cerebral Blood Flow) studies were performed preoperatively, early and late postoperatively. The patients that were diagnosed to have postoperative cerebral hypoperfusion also underwent computed tomography scanning postoperatively. RESULTS: Eleven patients (9 from fentanyl and 2 from thiopentone group) were diagnosed to have cerebral hypoperfusion with respect to SPECT rCBF studies. Seven of these patients (5 from fentanyl and 2 from thiopentone) were diagnosed to be in a state of delirium clinically with MMSE tests. CONCLUSION: High dose fentanyl anesthesia causes significant predisposition to postoperative cerebral hypoperfusion when compared with barbiturate anesthesia in cardiac surgery. Hypoperfusion as demonstrated by SPECT rCBF studies may play an important role in the pathophysiology of mental disorders, i.e., postoperative delirium.

Adult↗
PubMed1997

Pulmonary microvascular injury following general anaesthesia with volatile anaesthetics--halothane and isoflurane: a comparative clinical and experimental study.

Pulmonary microvascular injury has become a recently studied phenomenon that may be responsible for most of the complications associated with the lungs. Thirty patients undergoing partial hemilaminectomy or discectomy due to hernia of nucleus pulposus underwent Tc-99m HMPAO lung clearance as well as Tc-99m pertechnetate lung scintigraphy pre-operatively, and following general anaesthesia with halothane and isoflurane (third, fourth and tenth post-operative days). The results were compared with conventional techniques and haemodynamic parameters during the peri-operative period. In order to demonstrate acute phase changes under general anaesthesia and to perform pathological examinations, 21 New Zealand rabbits underwent radionuclide studies with Tc-99m HMPAO or Tc-99m pertechnetate. Lung biopsies were also performed. Despite no significant differences in any of the conventional diagnostic techniques, Tc-99m pertechnetate lung scintigraphy was performed for both the halothane and isoflurane groups, and Tc-99m HMPAO lung clearance was performed for the isoflurane group pre- or post-operatively. Tc-99m HMPAO lung clearance was impaired significantly in the halothane group on the third post-operative day (half time: 6.4 +/- 1.6 pre-operative and 13.76 +/- 3.3 s, P < 0.001) decreasing to pre-operative levels on the tenth post-operative day. Acute phase exposure to halothane was characterized with extremely abnormal Tc-99m HMPAO lung clearance in rabbits with respect to isoflurane, diminishing to control levels on the third day (half time: 8.7 +/- 86 control and 28.65 +/- 4.6, P < 0.001). Pathological examinations also demonstrated endothelial damage on acute exposure in the halothane group. General anaesthesia with halothane may give rise to alveolar microvascular injury, which generally seems to be underdiagnosed and may lead to serious post-operative complications.

Adult↗