Thoracic paravertebral block for postoperative pain management in percutaneous nephrolithotomy patients: a randomized controlled clinical trial.

OBJECTIVE: To investigate the effect of thoracic paravertebral block (PVB) on pain control and morphine consumption in percutaneous nephrolithotomy operations. SUBJECTS AND METHODS: This randomized controlled clinical study was performed on 60 American Society of Anesthesiologists (ASA) I-II patients between the ages of 18 and 60 years who underwent percutaneous nephrolithotomy with approval of the ethical committee and written consent of the patients. Patients were randomly allocated into two groups: group P had 4 ml of 0.5% levobupivacaine injected at each of the T10, T11, and T12 paravertebral spaces and a standard PVB, and group C received 4 ml of 0.9% NaCl solution. All patients were given standard general anesthesia. The follow-up of saturation, heart rate, peripheral oxygen, and blood pressure values was recorded before induction, intraoperatively, and postoperatively. At postoperative 1, 2, 6, 12, and 24 h, the visual analog scale (VAS), Ramsey sedation score, respiratory rate, and 24-hour total morphine consumption were recorded. In addition, side effects and satisfaction of patients were recorded. RESULTS: VAS scores and total morphine consumption were lower in group P than in group C: 2.3 vs. 4.3 and 22.3 vs. 43.2 mg, respectively (p < 0.05). The level of satisfaction was higher in group P than group C. Differences between groups in other parameters were not significant. CONCLUSIONS: Thoracic PVB with levobupivacaine provided a good postoperative analgesia and increased patient satisfaction for those who underwent percutaneous nephrolithotomy.

Cerebral arterial air embolism associated with mechanical ventilation and deep tracheal aspiration.

Arterial air embolism associated with pulmonary barotrauma has been considered a rare but a well-known complication of mechanical ventilation. A 65-year-old man, who had subarachnoid hemorrhage with Glasgow coma scale of 8, was admitted to intensive care unit and ventilated with the help of mechanical ventilator. Due to the excessive secretions, deep tracheal aspirations were made frequently. GCS decreased from 8-10 to 4-5, and the patient was reevaluated with cranial CT scan. In CT scan, air embolism was detected in the cerebral arteries. The patient deteriorated and spontaneous respiratory activity lost just after the CT investigation. Thirty minutes later cardiac arrest appeared. Despite the resuscitation, the patient died. We suggest that pneumonia and frequent tracheal aspirations are predisposing factors for cerebral vascular air embolism.

Hypotensive anaesthesia with remifentanil combined with desflurane or isoflurane in tympanoplasty or endoscopic sinus surgery: a randomised, controlled trial.

OBJECTIVE: To compare the effect of remifentanil combined with desflurane or isoflurane on the quality of the operative field and surgical conditions, blood loss, and recovery during tympanoplasty or endoscopic sinus surgery. DESIGN: Randomised, double-blinded clinical study. SUBJECTS: Sixty-four patients were scheduled for elective tympanoplasty or endoscopic sinus surgery. The patients were randomly divided into two groups: desflurane or isoflurane. After anaesthesia induction, all patients received a continuous remifentanil infusion of 0.2-0.5 microg/kg/min until a mean arterial pressure of 65-75 mmHg was achieved. Heart rate and mean arterial pressure were recorded throughout anaesthesia. Blood loss was measured at the end of surgery. Achievement of a bloodless operative field was rated on a 100 mm visual analogue scale. Following completion of surgery, the time to extubation and to achievement of an Aldrete score of nine or more was recorded. RESULTS: Sixty-three patients were evaluated. The total dose of remifentanil and the total blood loss were similar in both groups (p > 0.05). Time to extubation and to an Aldrete score of nine or more for the desflurane group was significantly less than for the isoflurane group (p 0.05). CONCLUSION: Although desflurane and isoflurane both enabled good surgical conditions (in terms of quality of operative field) and convenient induction of hypotension for tympanoplasty and endoscopic sinus surgery, the recovery characteristics of desflurane were better than those of isoflurane. Therefore, desflurane may be preferable to isoflurane in such circumstances.

Investigation of the relaxant effects of propofol on ovalbumin-induced asthma in guinea pigs.

BACKGROUND AND OBJECTIVE: Because the incidence of asthma appears to be increasing, the importance of proper perioperative management of individuals with asthma will also continue to increase. Although its mechanism of smooth muscle relaxation is unknown, propofol has been associated with less bronchoconstriction during anaesthetic induction. The aim of this study was to investigate the possible mechanism of these effects and the effects of propofol on the isolated trachea preparations from control and ovalbumin-sensitized guinea pigs. METHODS: Adult male guinea pigs, weighing 280-330 g, were randomly allocated to two experimental groups, each consisting of 10 animals. Ten guinea pigs were sensitized by intramuscular injections of 0.30 mL of a 5% (w/v) ovalbumin/saline solution into each thigh (0.6 mL total) on days 1 and 4, whereas the remaining 10 served as controls receiving a total of 0.6 mL distilled water on days 1 and 4 as placebo. The isolated trachea preparations were mounted in tissue baths with modified Krebs-Henseleit solution and aerated with 95% oxygen and 5% carbon dioxide. We tested the effects of propofol (10(-7)-10(-3) M) on resting tension and after precontraction with carbachol and histamine on isolated trachea preparations from control and ovalbumin-sensitized guinea pigs. We also tested the effect of propofol on isolated trachea preparations precontracted with carbachol and histamine in the absence and presence of different inhibitors or antagonists. We investigated propofol responses in tracheal smooth muscle precontracted with CaCl2. RESULTS: Propofol (10(-7)-10(-3) M) produced a concentration-dependent relaxation of isolated tracheal preparations precontracted by carbachol (10(-6) M) and histamine (10(-6) M) in both groups. Preincubation with N(w)-nitro L-arginine methyl ester (3x10(-5) M), indomethacin (10(-5) M) or propranolol (10(-4) M) did not produce a significant alteration on propofol-induced relaxation responses (P>0.05), while preincubation with tetraethylammonium (3x10(-4) M) significantly decreased the propofol-induced relaxation responses in both groups (P<0.05). Propofol (10(-7)-10(-3) M) induced concentration-dependently relaxations in isolated trachea rings precontracted with CaCl2 in both the control and ovalbumin-sensitized groups. CONCLUSION: Propofol induced concentration-dependent relaxations in precontracted, isolated trachea smooth muscle of guinea pigs in both the control and ovalbumin-sensitized groups. These relaxations were independent of epithelial function and stimulation of beta adrenergic receptors. Opened Ca2+-sensitive K+ channels and inhibited L-type Ca2+ channels can contribute to these relaxations.

Acute amitraz intoxication: retrospective analysis of 45 cases.

OBJECTIVE: To present special clinical and laboratory features of 45 cases (44 adult cases) who were intoxicated through oral route. DESIGN: Retrospective study. SETTING: Intensive care unit (ICU) of a university hospital. PATIENTS: Forty-five patients admitted to the ICU of Cumhuriyet University Hospital. RESULTS: Forty-five patients between 4 and 97 years of age were evaluated. Intoxication was the result of a suicide attempt in 67% of cases and accidental in 33% of cases. Unconsciousness, nausea and vomiting were the common initial symptoms. The major clinical findings in the ICU were bradycardia, myosis, hypothermia, hyperglycemia, hypotension, coma and respiratory depression. Blood glucose level was increased in 64% of cases. No problem was noted in the patient or the fetus in a pregnant, 27-year-old patient, who was intoxicated with 10 mL of 12.5% amitraz. The length of stay in the ICU was between 2 and 15 days. None of the patients died. All patients were discharged without neurological sequela. CONCLUSION: The prognosis of amitraz intoxications through oral route is benign and results in complete healing; however, we suggest that these cases should be well monitored and followed-up in ICUs.

Effects of propofol on vascular smooth muscle function in isolated rat aorta.

This study was undertaken to determine the direct actions of propofol, and whether propofol exerts any action on basal endothelium-derived relaxing factor release and vasodilator effect of acetylcholine on phenylephrine-induced contractile responses in isolated rat aortic rings. This compound is known to produce a fall in blood pressure in man and animals, and it has been suggested that the hypotension may result from a direct vasodilator action on the veins and arterioles. In this study, propofol did not induce any contractile response in aortic rings at various concentrations (10(-8)-10(-4) M). Propofol did not significantly alter phenylephrine-induced contractions at lower concentrations (10(-8)-10(-6) M) but at higher concentrations (10(-5)-10(-4) M) the depression caused by propofol was significant in both endothelium-intact and -denuded rings. Pretreatment of the endothelium-intact rings with propofol (10(-6) and 10(-5) M) produced a reduction in the relaxant effect of acetylcholine. The results obtained in this study demonstrate that clinically relevant concentrations of propofol (10(-6) M or less) have no direct vasodilator effects and that it reduces endothelium-dependent relaxation to acetylcholine.