Selda Sen

The Analgesic Effect of Nitroglycerin Added to Lidocaine on Intravenous Regional Anesthesia

We evaluated the analgesic effect of nitroglycerine (NTG) when added to lidocaine in IV regional anesthesia. Thirty patients undergoing hand surgery were randomly assigned to two groups. The control group (group C, n = 15) received a total dose of 40 mL with 3 mg/kg of lidocaine diluted with saline, and the NTG group (group NTG, n = 15) received an additional 200 μg NTG. Hemodynamic variables, tourniquet pain measured before and 1, 5, 10, 20, and 30 min after tourniquet inflation, and analgesic requirements were recorded during the operation. After the tourniquet deflation, at 1 and 30 min and 2 and 4 h, visual analog scale (VAS) score, time to first analgesic requirement, total analgesic consumption in the first 24 h after operation, and side effects were noted. Shortened sensory and motor block onset time (3.2 ± 1.1 versus 4.5 ± 1.2 min; P = 0.01 and 3.3 ± 1.6 versus 5.2 ± 1.8; P = 0.009 in group NTG and group C, respectively), prolonged sensory and motor block recovery times (6.8 ± 1.6 versus 3.1 ± 1.2 min P < 0.0001 and 7.3 ± 1.3 versus 3.6 ± 0.8 P < 0.0001 in group NTG and group C, respectively), shortened VAS scores of tourniquet pain (P = 0.023), and improved quality of anesthesia were found in group NTG (P < 0.05). VAS scores were lower in group NTG after tourniquet release and in the postoperative period (P = 0.001). First analgesic requirement time was longer in group NTG (225 ± 74 min versus 39 ± 33 min) than in group C (P < 0.0001). Postoperative analgesic requirements were significantly smaller in group NTG (P < 0.0001) but the side effects were similar in both groups. We conclude that the addition of NTG to lidocaine for IV regional anesthesia improves sensory and motor block, tourniquet pain, and postoperative analgesia without side effects.

The persisting analgesic effect of low-dose intravenous ketamine after spinal anaesthesia for Caesarean section

Background and objectives: To compare the analgesic effects of intrathecal fentanyl and low‐dose intravenous ketamine as adjuvants to intrathecal bupivacaine for Caesarean section. Methods: Ninety elective Caesarean section patients were randomized into three groups. Spinal anaesthesia was performed with 15 mg hyperbaric bupivacaine in all groups. Ketamine (0.15 mg kg−1) or an equal volume of normal saline was given intravenously immediately after initiating spinal anaesthesia in the ketamine and control group, respectively. In the fentanyl group, 10 μg fentanyl was added to the intrathecal bupivacaine. Arterial pressures, heart rate values, adverse effects, the time of first request for postoperative analgesia, visual analogue pain scores, total analgesic consumptions at 24 and 48 h were recorded in all patients. Results: The time to first request for analgesia was significantly longer in the ketamine (197 min) and fentanyl (165 min) groups compared to the control group (144 min). Postoperative pain scores were significantly lower in the ketamine group than in both other groups. Although the analgesic requirements during first 24 h were significantly lower in the ketamine group, there was no significant difference between the groups during the following 24 h. Conclusion: Intravenous low‐dose ketamine combined with intrathecal bupivacaine for Caesarean section provides longer postoperative analgesia and lower postoperative analgesic consumption than bupivacaine alone suggesting a pre‐emptive effect.

The Effects of Spinal Anesthesia on QT Interval in Preeclamptic Patients

In this study, we measured the effects of spinal anesthesia on the corrected QT (QTc) interval in women with severe preeclampsia. Twenty-five preeclamptic (preeclamptic group) and 25 healthy pregnant women with normal arterial blood pressure and QTc interval (control group) were enrolled in this prospective, case-controlled study. Arterial blood pressure, heart rate, and QTc interval values were obtained before (baseline value) and at 5, 10, 20, 30, 60, and 120 min after initiation of spinal anesthesia. Total ephedrine dose, time elapsed until sensory block, and Apgar scores were recorded. Prior to spinal anesthesia, QTc interval values were significantly higher in the preeclamptic group (452 ± 17.5 ms) when compared with that in controls (376 ± 21.4 ms). Although the QTc interval shortened during spinal anesthesia when compared with baseline value in the preeclamptic group (P < 0.05), it showed no significant change in the control group. In conclusion, the QTc interval may be prolonged in severe preeclamptic patients who have hypertension and hypocalcemia. Spinal anesthesia for cesarean delivery may normalize that prolonged QTc interval due to sympathetic blockade.

Topical Heparin: A Promising Agent for the Prevention of Tracheal Stenosis in Airway Surgery

BACKGROUND The protective effects of topical mitomycin-C (MMC) have been well documented for tracheal stenosis; however, to the best of our knowledge, the use of heparin as an anti-inflammatory agent to support wound healing in upper airway surgery was not studied before. The aim of this study was to investigate the efficacy of topical heparin for healing of tracheal re-implants in a rabbits model and its resultant histological changes compared with that of MMC. METHODS In a rabbit model (n = 21), an elliptically shaped portion of the anterior tracheal wall was excised (3-4 tracheal cartilages) under anesthesia and immersed in an isotonic saline solution containing 0.4 mg/mL (0.04%) MMC (n = 7), heparin (liquemine) 5000 U/mL (n = 7), or none (n = 7) for 2 min and then re-implanted. The follow-up period was 2 wk for all animals and then both the larynx and the trachea were excised for histological evaluation. Hematoxylin-eosin (H and E) staining was applied to the excised tissues for microscopic evaluation. RESULTS Compared with controls, the granulation tissue formation score in MMC group (P = 0.03), and epithelial regeneration and inflammation scores in heparin group (P = 0.032 and P = 0.022, respectively) were more favorable. The fibrosis index and tracheal lumen ratio values were also more favorable in both MMC (P = 0.019 and P = 0.0028, respectively) and heparin (P = 0.023 and P = 0.0021, respectively) groups compared with controls on the 15th d. CONCLUSIONS Topical heparin application may have favorable effects on healing of tracheal autografts in a rabbit model. We suggest that heparin therapy should be further researched for the prevention of tracheal stenosis in airway surgery.

Comparison of single-breath vital capacity rapid inhalation with sevoflurane 5% and propofol induction on QT interval and haemodynamics for laparoscopic surgery.

Background and objective: To compare two techniques to achieve induction of anaesthesia for laparoscopic surgery. A single-breath vital capacity rapid inhalation induction with sevoflurane was compared to intravenous propofol. Their effects on haemodynamics and the QT interval of the electrocardiogram were assessed. Methods: Forty-four ASA I-II patients scheduled to undergo elective laparoscopic gynaecological surgery were divided into two groups. In the sevoflurane group (Group S, n = 22), general anaesthesia was induced with a single-breath vital capacity rapid inhalation of sevoflurane 5% with nitrous oxide (N2O) 65% in O2 and then anaesthesia was maintained with sevoflurane 1-1.5% with N2O 65% in O2. In the propofol group (Group P, n = 22), general anaesthesia was induced with propofol 2 mg kg−1 intravenously and maintained with propofol 6 mg kg−1 h−1. Systolic, diastolic and mean arterial pressures, heart rate and end-tidal CO2 values were recorded before anaesthesia (basic value), during the induction period (time X), at 10 min (time Y) and at 30 min (time Z) of CO2 insufflation in all patients. QT intervals were calculated using Bazetts equation. Results: Systolic, diastolic and mean arterial pressure values during the induction period (time X) were lower than the basic value in both groups (P < 0.05). In Group S, QTc intervals were significantly longer during the induction period (time X) and at the tenth min of CO2 insufflation (time Y) than Group P (P < 0.05). Five patients at time X and two patients at time Y developed ventricular dysrhythmias, which improved spontaneously in Group S. In Group P, there was no significant difference in QTc intervals and only one patient developed a ventricular dysrhythmia at time Y. Conclusions: Single-breath vital capacity rapid inhalation induction technique with sevoflurane can cause prolongation of the QT interval and dysrhythmias, compared with induction and maintenance of anaesthesia with propofol in laparoscopic surgery.

Effects of Sevoflurane on QT Dispersion and Heart Rate Variability

The purpose of this study was to use estimates of corrected QT dispersion (QTcd) and heart rate variability (HRV) to assess the effects of sevoflurane, an inhalation agent used frequently in clinical practice, on autonomic cardiac function. This study was conducted prospectively and in a blind manner on 20 women between 38 and 51 y of age who were classified as American Society of Anesthesiologists stage I–II and whose treatment required total abdominal hysterectomy. Electrocardiograms were recorded by 12-lead Holter monitor for 5 min before sevoflurane induction and again for 5 min at 10 min after tracheal intubation. Data on the first recording were considered as baseline; those on the second recording were viewed as final data. The study was terminated at this point, and surgery was allowed to proceed. QTcd and HRV values were assessed by a cardiologist, who was blinded to all data. All parameters were expressed as a mean value ± standard deviation. Wilcoxon’s test was used to compare baseline and final data. Statistical significance was considered asP< .05. No significant changes were observed between baseline and final QTcd values and between low and high-frequency components (LF and HF) of HRV; nor were changes seen in the LF/HF ratio. With the patient under sevoflurane/nitrous oxide anesthesia, no significant changes were detected in QTcd, LF, and HF values, and in the LF/HF ratio, whereas a significant increase (P=.001) was seen in standard deviation of the R-R interval, which was used as a measure of cardiac autonomic tone.

The Antioxidative Property of Nitroglycerin Enhances LornoxicamâÂÂs Antiinflammatory Effect

Background and objectives: The aim of the study is to evaluate the effect of combination of nitroglycerin and lornoxicam on nociception and antioxidative system in rats. Methods: Thirty-nine Wistar male rats were divided into five groups; control group (Group C, n=7), isotonic group (0.09 sodium chloride, Group ISO, n=8 ), lornoxicam group (lornoxicam 1.3 mg kg-1, Group L, n=8), nitroglycerin group (nitroglycerin 1 mg kg-1, Group N, n=8), and lornoxicam-nitroglycerin combination group (1.3 mg kg-1 lornoxicam+1 mg kg-1 nitroglycerin Group L+N, n=8). Hot plate test was applied in all groups before and at 30, 60, 90 minutes after drug injections by intraperitoneal route. Malondialdehyde, nitric oxide, glutathione, and catalase concentrations were measured before and after 90 minutes of drug injection in all blood samples. Results: The latency response of hot plate test was increased in Group L+N at 30 minutes, and Group L and Group L+N at 60 and 90 minutes (p<0.05). Malondialdehyde levels were decreased, while catalase and glutathion levels were increased in N and L+N groups (p<0.05). Conclusion: Nitroglycerin enhances the antioxidative effects of lornoxicam for antinociception but different mechanisms might also play a role on antinociception. Further studies must be carried out with experimental models and different drug doses to reach an ultimate conclusion.

The use of train of four monitoring for clinical evaluation of the axillary brachial plexus block.

Abstract The axillary approach of brachial plexus anesthesia is the most commonly used technique for forearm and hand surgery. Dynamometer is known as objective test for the clinical assessment of motor block of the nerves in brachial plexus block. However, the use of this device may not always be practical in operating room. The train-of-four (TOF) test is a non-invasive peripheral nerve stimulator that shows the level of motor block of muscle relaxants. The aim of the study is to investigate the use of TOF testing as a peripheral nerve stimulator for objective clinical evaluation of motor block at axillary brachial plexus block. 44 patients were randomized according to the development of partial or complete motor in the axillary brachial plexus block. The nerves were selectively localized by nerve stimulation and ultrasound guidance. After obtaining an appropriate peripheral motor response, predetermined volumes of bupivacaine were selectively injected to the 4 nerves. Sensory, motor block levels and TOF values were measured at 10th, 20th, 30th minutes immediately after the axillary brachial plexus block. TOF values were gradually decreased and significant difference was observed between the development of a complete and partial motor block at 30th minute. TOF values were also significantly less in patients of complete sensory block than the patients of partial sensory block at 30th minute. The use of TOF monitoring may be beneficial to assess the objective clinical effect of motor block in the patients with axillary brachial plexus nerve block.

366 THE EFFECTS OF TRAMADOL AND COMBINATION OF NITRIC OXIDE WITH TRAMADOL ON ACUTE INFLAMMATORY PAIN IN RATS

plantar hindpaw to determine a withdrawal force threshold. COX expression in spinal cord was compared among groups of mice using reverse transcriptase polymerase chain reaction (RT-PCR). Results: Before carrageenan injection, there was no difference in withdrawal to von Frey filaments among the 5 mice groups. After injection, mechanical hyperalgesia was greatest (p < 0.05) in COX-2 (−/−) mice compared to any other group, while wild mice had the least mechanical hyperalgesia of any group. RT-PCR analysis of spinal cords did not reveal any compensatory expression of the COX genes. Conclusions: Mechanical withdrawal thresholds following carrageenan injection is decreased in COX-1 or -2 deficient mice compared with control wild mice. This may be due to factors other than reciprocal COX compensation in the spinal cord.

242 THE EFFECTS OF NITROGLYCERIN‐LORNOXICAM COMBINATION ON ANTINOCICEPTION IN RATS

Background and Aims: In behavioural analgesic assays, confounding factors, e.g. decrease in motor activity, may interfere with the readout. Administration of drugs often requires vehicles more complicated than saline but the vehicle effect on motor activity is commonly neglected. The aim was to study possible effects of vehicles on locomotion and on the nociceptive response following formalin injection. Methods: The formalin test was performed by injecting 20 mL of 2.7% formalin (in saline) subcutaneously on the dorsal side of the left hind paw in male NMRI mice (n = 8/group). The nociceptive behaviour as well as motor activity (locomotion, rearing and immobility) was analysed by an automated computer system (LookNT 6.54), based on image analysis, 15 min after administration of different vehicle solutions (10mL/kg). Results: Compared to saline, subcutaneous (SC) administration of a cosolvent vehicle, a glycol derivate vehicle or 0.3 M Gluconic acid or per oral (PO) administration of 15 % DMA or the co-solvent vehicle significantly reduced both motor activity and pain behaviour. No significant effect was seen after SC injection of 5% DMA, 40% PEG or 0.3M Meglumin or after PO administration of 5% or 10% DMA, 0.3M Meglumin or 0.3M Gluconic acid. Conclusion: Several vehicles decreased both nociceptive behaviour and motor activity measures suggesting that these vehicles should be avoided in behavioural tests in mice.