Ismail Kati

Effects of dexmedetomidine on the duration of anaesthesia and wakefulness in bupivacaine epidural block

Background: The purpose of this study was to examine the effects of intravenous dexmedetomidine on the duration of bupivacaine‐induced epidural anaesthesia and level of wakefulness and the respective side‐effects. Methods: Sixty ASA I–II patients were included in the study. Consecutive patients were allocated to groups according to the last digit (odd/even) of their admission numbers. All patients had epidural anaesthesia with bupivacaine 0.5% performed by the same experienced anaesthesiologist. In the first group, the patients were administered intravenous dexmedetomidine infusion just after the epidural block and continued during the operation, while those in the second group were administered physiologic saline infusion at the same amount and duration. Results: The recovery time of sensory block was significantly longer in the first group. The bispectral index values were lower in the first group than in the second. Also, heart rate was significantly lower in Group I than in Group II. Regarding side‐effects, shivering was significantly less frequent in the first group, whereas there was a significant increase in the requirement of atropine in the first group as dexmedetomidine caused bradycardia. Conclusion: Intravenous administration of dexmedetomidine prolonged the duration of epidural anaesthesia, provided sedation and had few side‐effects.

Comparison of the effects of desflurane and sevoflurane on the QTc interval and QT dispersion

Objective — The effects of desflurane and sevoflurane on QT interval and QT dispersion have been investigated in a prospective, double-blind, randomized study of patients undergoing noncardiac surgery. Interventions — Sixty American Society of Anaesthesiologists physical status I-II adult patients were randomly assigned to two groups.Anaesthesia was induced with inhalation of desflurane (desflurane group) or sevoflurane (sevoflurane group) in increasing concentrations to 3 minimal alveolar concentration level. The maintenance of anaesthesia was provided with 2 minimal alveolar concentration agents in both groups until the end of the study. Electrocardiogram, heart rate and blood pressure were recorded as follows: before premedication, before induction, 1 and 3 min after the induction of anaesthesia, after the administration of vecuronium and after the tracheal intubation. The induction times and the complications were recorded. Measurements and results — The QTc interval was significantly more prolonged with desflurane than with sevoflurane at the first and third minute after the induction, and at the third minute after the administration of vecuronium.There were no significant differences in the QT dispersion between the two groups. Heart rate and blood pressure were found to be significantly higher in the desflurane group. Conclusion — The QTc interval was more prolonged with desflurane than sevoflurane, and QT dispersion was normal with both agents.

Does Benzydamine Hydrochloride Applied Preemptively Reduce Sore Throat Due to Laryngeal Mask Airway

Sore throat is a common postoperative complaint. We investigated whether preemptive benzydamine hydrochloride (BH) treatment could prevent sore throat due to a laryngeal mask airway (LMA) cuff inflated with air. One-hundred ASA status I–II patients who underwent general anesthesia were randomly divided into two groups. In the first group, four puffs of BH were applied to the pharynx 30 min before the operation and 5 min before the induction of anesthesia. Distilled water with a similar bottle was applied with the same protocol in the second group. Anesthetic induction was provided with propofol and fentanyl. The pressure of the LMA cuff inflated with room air was measured after the first adjustment and after 30, 60, and 90 min of inflation in both groups. At the end of operation, the LMA was removed after the recovery of spontaneous breathing. After the operation, patients were asked about sore throat symptoms at the first, second, and fourth hours. There were no significant differences between groups for cuff pressures, cuff volumes, analgesic doses, or operation times. However, sore throat symptoms were significantly less severe for the BH group during both resting and swallowing. In conclusion, preemptive topical BH may decrease the incidence of sore throat due to LMA use.

Management of a severe carbamazepine overdose with continuous venovenous hemodiafiltration.

Carbamazepine (CBZ) is a commonly used antiepileptic agent. Common toxic effects include neurological abnormalities; ataxia, seizures, coma, cardiorespiratory problems; dysrhythmias; conduction disorders; respiratory depression; and eye abnormalities, such as nystagmus and ophthalmoplegia. Carbamazepine is highly protein bound. There is no antidote for the medication. Carbamazepine is not removed effectively through conventional hemodialysis. Supportive measures and charcoal hemoperfusion have been regarded as efficient treatment methods. We herein report a 17-year old girl to whom continuous venovenous hemodiafiltration lacking the albumin-enhance after suicidal overdose of CBZ was performed. We suggest continuous venovenous hemodiafiltration lacking the albumin-enhance as an alternative emergency treatment modality for cases who had ingested CBZ in toxic levels.

Effect of Dexmedetomidine IV on the Duration of Spinal Anesthesia with Prilocaine: A Double-Blind, Prospective Study in Adult Surgical Patients

BACKGROUND The duration of spinal anesthesia with prilocaine has been poorly documented and no English-language study has been published regarding the effects of dexmedetomidine on the duration of anesthesia with spinal prilocaine. OBJECTIVE The aim of this study was to assess the effects of dexmedetomidine IV on the duration of action of prilocaine and its associated adverse events (AEs) in spinal anesthesia. METHODS In this double-blind, prospective study, patients classified as American Society of Anesthesiologists grade I to II who were to undergo lower abdominal, anorectal, or extremity surgery with a spinal anesthetic were assigned to 1 of 2 groups. All patients were administered prilocaine 2% for spinal anesthesia. Within 10 minutes after spinal anesthesia was initiated, group 1 received a loading dose of dexmedetomidine 1 μg/kg IV, followed by a maintenance dose of 0.4 μg/kg · h for 50 minutes; group 2 (control) received the same amount of physiologic saline in the same time frame. Mean arterial pressure (MAP), heart rate (HR), duration of sensory and motor blockade, and sedation scores were tracked. Patients were observed for 4.5 hours after surgery, with follow-ups occurring up to 96 hours after surgery. RESULTS Eighty-three patients were assessed for study inclusion, 23 of whom were excluded. Sixty patients (42 men, 18 women; mean [SD] age, 40.56 [16.86] years) were included in the study. MAP was similar in the 2 groups throughout the study. Mean (SD) HR was significantly lower in group 1 compared with group 2 at 20 minutes (70.43 [19.28] vs 77.63 [18.14] beats per minute, respectively; P = 0.02). The mean (SD) duration of the persistence of sensory anesthesia (ie, the time required for the maximal level of anesthesia to regress 2 dermatomes) was significantly longer in group 1 compared with group 2 (148.33 [21.18] vs 122.83 [18.73] minutes; P < 0.001). The mean (SD) time to complete abolishment of motor blockade was also significantly longer in group 1 than in group 2 (215.16 [25.10] vs 190.83 [18.57] minutes; P < 0.001). The average sedation score in group 1 was significantly higher than in group 2 (P < 0.001) during anesthesia. Significantly more patients in group 1 required atropine than those in group 2 (9 vs 2 patients; P < 0.001) to treat bradycardia. There was no significant between-group difference in the number of patients who received ephedrine to treat hypotension. One patient in each group reported waist and back pain; 2 patients in each group reported nausea. Shivering occurred in 0 and 5 patients in groups 1 and 2, respectively; the between-group difference in AEs was not statistically significant. Paresthesia, postdural puncture headache, allergic reactions, total spinal anesthesia, urinary retention, or vomiting-AEs commonly associated with spinal anesthesia-were not observed or reported by either group. CONCLUSIONS The results of this study suggest that dexmedetomidine IV significantly prolonged the duration of spinal anesthesia and provided a significantly higher level of sedation compared to placebo in this group of adult surgical patients. The treatment was generally well tolerated in all patients.

Comparison of the effects of room air and N2O + O2 used for ProSeal LMA cuff inflation on cuff pressure and oropharyngeal structure

This study aimed to evaluate the effects of different inflating gases used for ProSeal LMA (PLMA) cuff inflation on cuff pressure, oropharyngeal structure, and the incidence of sore throat. Eighty patients (American Society of Anesthesiologists; ASA I–II) were randomly divided into two groups. PLMA cuff inflation was achieved with appropriate volumes of 50% N2O + 50% O2 in group I and room air in group II, respectively. When the PLMA was removed, oropharyngeal examination was carried out immediately, using a rigid optical telescope. Patients were asked about sore throat symptoms postoperatively. Cuff pressures were significantly lower in group I, except at the initial pressure measurement. Cuff pressure was positively correlated with the length of the operation in group II, and negatively correlated in group I. PLMA cuff inflation with room air led to increased cuff pressure during the operation, possibly due to the diffusion of N2O into the cuff. We consider that a PLMA cuff inflated with an N2O-O2 mixture is convenient, especially in operations in which N2O has been used.

Alterations in the biochemical markers of renal function after sevoflurane anaesthesia

Aim:  This study has been carried out to see whether renal function is acutely altered in patients undergoing sevoflurane anaesthesia. For this purpose, the urinary levels of markers of renal tubular function, namely leucine amino peptidase (LAP), gamma‐glutamyl transferase (GGT), alkaline phosphatase (ALP), lactate dehydrogenase (LDH) and beta‐2 microglobulin (beta‐2M), and urinary albumin as a predictor of renal glomerular function were measured before and after sevoflurane anaesthesia.

Management of outpatient anesthesia in an unusually case with glutaric aciduria type-1.

SIR—Glutaric aciduria type-1 (GA-1) is an autosomal recessive, uncommon and severe metabolic disorder with a deficiency of glutaryl-CoA dehydrogenase. This disorder mainly detects in early childhood (1). Most children with this disorder have no measurable enzyme activity, but several have had 10–15% residual enzyme activity (2). The population frequency has been estimated at 1 in 30 000 neonates in a Scandinavian study (3). Most patients have a dystonic–dyskinetic syndrome. The patient’s symptoms are psychomotor delay, dystonia, spastic quadriparesis and macrocephaly (1). In the literature only two cases with GA-1, who underwent general anesthesia, were reported (4). Our cases are two sisters with GA-1, who were aged 12 (39 kg) and 16 (51 kg) years, respectively, and presented with macrocephaly and psychomotor delay. Laboratory analysis yielded urinary glutaric acid values of 157 and 153 nmolÆmol creatinine (normal: 0–5.3), respectively. On preanesthetic clinical examination, macrocephaly was observed, with an occipitofrontal circumference of 58 cm and 62 cm (>98%). They were hypotonic, especially in both arms and her reflexes were normal. Their optics discs were pale, and a dystonic posturing of both hands was noted. Father and mother weren’t consanguineous. There required sedation for magnetic resonance imaging during routine follow up. The cases weren’t premedicated before sedation. They were continuously monitored by electrocardiogram, oxygen saturation (SpO2), body temperature, and noninvasive blood pressure. A 22 G intravenous cannula was inserted in the arm and a fluid infusion was started with dextrose in normal saline instead. Sedation was achieved by using bolus of propofol 1 mgÆkg. Sedation was maintained using a bolus of propofol 0.5 mgÆkg in case of necessity and spontaneous breathing was maintained during this time period. Oxygen was administered via facemask. Procedures time were approximately 10 mins. All the monitored parameters remained within normal ranges during the procedures. The procedures were completed uneventfully. They were being treated with a low-protein diet, riboflavin, and carnitine. The patients were discharged home 1 h after the procedure. GA-1 prevails in communities with a high rate of consanguineous marriages or in groups who are ethnically or culturally isolated. The father and mother of our cases were not relatives. The cerebral damage seen in GA-1 is caused by the direct effect of glutaric acid in the brain and Cerebrospinal fluid (4). Acute neurological crises are typically precipitated by the glutaric acid passage through the blood-brain barrier associated with an infection or some physiological stress. The most common presenting symptoms of GA-1 are macrocephaly, hypotonia or diffuse rigidity, consciousness, seizures, and dystonic limb movements (4). Our patient’s symptoms were psychomotor delay, dystonia, spastic quadriparesis and macrocephaly. Metabolic manifestations, such as hypoglycemia and metabolic acidosis, are rarely present except in the acute phases of the disease (5). Our patients didn’t have a metabolic problem. The principles of the treatment of GA1 consist of an initial diet low in lysine and tryptophan to reduce total glutaric acid production, administration of oral L-carnitine supplements as all patients present a secondary carnitine deficiency, and riboflavin, a cofactor of glutaryl-CoA dehydrogenase (4). Our patients were also being treated with a low-protein diet, riboflavin, and carnitine. An emergency protocol is established for preventing encephalopathic crises that consists of a high-calorie dextrose infusion, rapid correction of fluid deficits, ensuring brisk output of alkaline urine, high-dose intravenous carnitine, and anticonvulsants usage (5). To prevent hypoglycemia and metabolic acidosis in our patients during the sedation, we avoided using Ringer’s lactate since it contains lactic acid, and used dextrose in normal saline instead. Joaquin et al., reported that there were no reports on the superiority of one anesthetic drug over another in patients with GA-1 in the literature (4). The following should be taken into consideration in anesthesia management: the possibility of pulmonary aspiration, prolonged responses to nondepolarizing muscle relaxants, and hyperkalemic responses to succinylcholine. The patients with severe dystonia may be at a greater risk for aspiration of gastric contents during general anesthesia. Appropriate measures to avoid aspiration or its complications must be undertaken, including fasting, use of H2 blockers and rapidsequence anesthesia induction with cricoid pressure (4). Before sedation, 25 mg of ranitidine was given intravenous to patients having fasting for 8 h in order to prevent aspiration of gastric content. We used a bolus of propofol to maintain a sedation as protected spontanaous breathing. In concluded that we suggested performing sedation with propofol without any difficulty in these cases. Ugur Goktas Ismail Kati Osman Cagatay Aytekin Department of Anesthesiology, Medical Faculty, Yuzuncu Yil University, Van, Turkey (email: mdugoktas@yahoo.com)

Difficult airway management in Lymphangiomatos Macroglossia

SIR—Lymphangiomas may be congenital or acquired and related to a host of genetically, metabolically, or anatomically defined conditions or lesions. Lymphangioma of the tongue may lead to a dry ⁄ cracked tongue with ulcerating secondary infections, difficulty in swallowing and mastication, speech disturbances, exclusive nasal breathing, airway obstruction, mandibular prognathism and other possible deformities of maxillofacial structures (1,2). Anesthetic concerns include bleeding, difficulty visualizing the airway, extrinsic and intrinsic pressure on the airway causing distortion, and enlarged upper respiratory structures, including the lips, tongue, and epiglottis (3). There seems to be a little information on the anesthetic management for this age group in English literature. We pay attention that huge lymphangioma of the tongue might cause various anesthetic problems especially on airways which we should keep in mind. A 4-year-old male with a clinical presentation of macroglossia is described, which was causing difficulty in eating, speaking, and breathing. The child’s parents were aware of the enlargement since birth and reported that the tongue continued to grow larger as the child aged. The child was otherwise developmentally healthy and of normal height (97 cm) and weight (20 kg). Clinically, the tongue appeared diffusely bulky, dry, and ulcerated but exhibited texture and movement. The child had a severe anterior open bite as a result of tongue thrust, with accompanying malocclusion and short neck. The child’s laboratory values, mental and psychological status, and neurological and other systematical examination findings were normal. The main indications of surgery were to obtain good cosmetic appearance and functional upper airway, thus it was decided to reduce the tongue size. Suggesting that intubation and airway management of the case would be difficult, the necessary preparations for difficult laryngoscopy and intubation were made. His airway was not obstructive even during sleep. Mallampati class was evaluated as one. Inhalation induction of anesthesia was not performed because of preoperative indirect laryngoscopy showed adequate space around the larynx. For 3 min, preoxygenation with 100% oxygen was obtained by the help of a mask which is large enough to cover his mouth, nose, and protruding tongue (Figure 1). Without problem, anesthesia induction was achieved with propofol and fentanyl without muscular relaxant after routine anesthesia monitoring. A laryngoscope blade was used one number bigger than expected. Although the vocal cords were invisible, endotracheal intubation was succeeded at first attempt by the help of a guidewire, and then muscular relaxant was administered. After intubation, tracheostomy was opened. Maintenance of anesthesia was provided by O2 ⁄ dry air, fentanyl, and vecuronium during the operation. After the operation, residual neuromuscular block was reversed after the patient gained ability to open his eyes and to respond to simple verbal command. The postoperative course was uneventful. Upper airway obstruction is a frequent problem in spontaneously breathing children undergoing anesthesia or sedation procedures. Failure to maintain a patent airway can rapidly result in severe hypoxemia, bradycardia, or asystole, as the oxygen demand of children is high and oxygen reserve is low (4). Macroglossia may interfere with normal breathing, particularly during sleep, produce sleep apnea, and in certain instances, producing a life-threatening upper airway compromise (2). The main responsibility of the anesthetist is to keep the airway open safely and to do what is necessary to continue the adequate gas exchange. Both direct laryngoscopy and endotracheal intubation are still the technics of choice in supplying safe airway. In such circumstances, controlling the airway becomes extremely difficult. The incidence of difficult intubation in non-obstetric cases was reported as 0.05–2% (5). Further intubation technics, such as fiber-optic intubation, retrograde intubation, and blunt nasal intubation are taken into consideration in cases whose airway have not been controlled because of anatomic and technical causes. As in our case with protruding macroglossia, it is possible to do endotracheal intubation without employing the alternate method of visualization of the vocal cords by indirect laryngoscopy. Nevertheless, in the presence of macroglossia protruding outwards, preoxygenation should be *Presented in part at the 41st Annual Meeting of the Turkish Society of Anesthesiology and Reanimation, Antalya, October 2007. Figure 1 Lateral view of the huge lymphangioma. CORRESPONDENCE 1127

Analysis of the effect of perioperative magnesium sulphate on minimal alveolar concentration of desflurane using bispectral index monitoring

BACKGROUND In this study we aimed to analyze the effect of perioperative magnesium sulphate (MgSO(4)) on minimal alveolar concentration (MAC) of desflurane using bispectral index (BIS) monitoring. PATIENTS AND METHODS Sixty patients undergoing abdominal surgery under general anesthesia were randomized into two groups: Mg - receiving perioperative MgSO(4) supplementation and C - control. Anesthesia was titrated to maintain the BIS value between 45-55. RESULTS MAC values, tachycardia and hypertension during intubation was found to be lower in group Mg compared to group C (p<0.001). Time to extubation, verbal cooperation and eye opening was longer in patients receiving infusion of MgSO(4) (p<0.001). CONCLUSION We concluded that perioperative MgSO(4) infusion may be used as an adjunct as it decreases MAC of desflurane and suppresses the hemodynamic response to intubation.