Vocal Cord Position Research Articles

Comparative evaluation of different doses of propofol preceded by fentanyl on intubating conditions and pressor response during tracheal intubation without muscle relaxants

The aim of our study was to determine the optimal dose of propofol preceded by fentanyl for successful tracheal intubation and to see its effectiveness in blunting pressor response in children aged 3-10 years. This prospective, double blind, randomized study was conducted on 60 ASA grade I and II children, between 3 and 10 years undergoing elective surgery who were divided into three groups of 20 each. The children received different doses of propofol (group I, 2.5 mg x kg(-1); group II, 3.0 mg x kg(-1); group III, 3.5 mg x kg(-1)) preceded by a fixed dose of fentanyl (3.0 microg x kg(-1)) 3 min earlier. The tracheal intubating conditions were graded based on scoring system devised by Helbo-Hensen et al. with Steyn modification which includes five criteria; ease of laryngoscopy, degree of coughing, position of vocal cords, jaw relaxation, and limb movement and graded on a 4-point scale. Heart rate (HR), mean arterial pressure (MAP), and oxygen saturation changes were also noted. Tracheal intubating conditions were acceptable in 25% of the patients in group I, while significantly higher (P < 0.001) in group II (80%) and in group III (90%). The pressor response was not effectively blunted in group I (17% increase in HR), while effectively blunted in groups II and III. A fall in cardiac output was seen in group III indicated by a decrease in MAP (16%) and HR (11%). No airway complications were noted. Propofol 3 mg x kg(-1) (group II) preceded by fentanyl 3 microg x kg(-1) is the optimal dose combination in our study. It provides acceptable intubating conditions in 80% patients, blunts pressor response to intubation without significant cardiovascular depression.

Adequate Dose of Remifentanil for Endotracheal Intubation with Propofol without Muscle Relaxants

Background: Many studies have shown that tracheal intubation could be facilitated after induction with propofol and opioids without muscle relaxants. Remifentanil, which has a rapid onset and ultra-short duration of action, is a useful estrase-metabolized opioid (EMO) for tracheal intubation. This study was designed to evaluate the adequate induction dose of remifentanil with propofol 1.5 mg/kg for tracheal intubation without muscle relaxants. Methods: We have assessed intubating conditions in five groups of 57 female patients, ASA PS I or II. Each group was administerd intravenous propofol 1.5 mg/kg with remifentanil 1.0/kg, 2.0/kg, 3.0/kg, 4.0/kg and 5.0/kg, respectively. Intubation was attempted, and the intubating condition was scored by the degrees of relaxation of jaw (0-2), position of vocal cords (0-2) and the patient response (0-2). Mean arterial pressure (MAP) and heart rate (HR) were observed at each group. Results: The relationship between the concentration of remifentanil and the possibility of endotracheal intubation was as following: Probit (P) = - 1.38 (S.E.: 0.58) + 0.087 (S.E.: 0.23) . The of remifentanil for endotracheal intubation without muscle relaxants was 2.12 (95% confidence interval: 1.42-2.62)/kg and the was 4.01 (95% confidence interval: 3.31-5.92)/kg. Conclusions: We concluded that adequate dose of remifentanil which make possible to endotracheal intubation without muscle relaxants after induction of general anesthesia with 1.5 mg/kg of propofol is 4.01/kg in 95% of female patients and 2.12/kg in 50% of female patients.

Effects of ephedrine on intubating conditions following priming with rocuronium

Onset of action of muscle relaxants is influenced by cardiac output and muscle blood flow. Ephedrine reduces the onset time of rocuronium. Onset is also shortened by priming. Accordingly, we hypothesized that priming combined with ephedrine is superior to either technique used separately. Four groups of randomly allocated patients (n = 31), ASA I - II, were induced with propofol 2.5 mg kg(-1). In groups I and II, 0.04 mg kg(-1) of rocuronium was followed by a 3-min priming interval. Induction was followed by an intubation dose of 0.04 mg kg(-1). Then a 30-s intubation was attempted. In groups III and IV the same sequence was repeated except for sham priming and an intubation dose of 0.44 mg kg(-1). In groups I and II, ephedrine (210 microg kg(-1)) was injected before propofol. In groups II and V, an equivalent volume of normal saline was injected. Jaw relaxation, vocal cord position, and diaphragmatic response were used to assess intubating conditions. All patients of group I were intubated 30 s after the intubating dose and within a 20-s interval compared with 74% of patients in groups II and III, and 84% of patients in group IV. Intubating conditions were graded good to excellent in all patients in group I compared with 42% of those in group II, 35% in group III and 52% in group IV (P < 0.01 vs. group I). During the priming interval, no adverse effects were observed or reported. Ephedrine in combination with propofol significantly improved clinical intubating conditions at 30 s following priming with rocuronium compared with priming with ephedrine without priming.

Comparative study of intubating conditions at the first minute with suxamethonium, rocuronium and different priming techniques of rocuronium

To evaluate orotracheal intubation conditions after 1 min. A prospective randomized study with 376 adult American Society of Anesthesiologists (ASA) Grade I-III patients. Each patient received propofol, fentanyl and either suxamethonium (1 mg kg(-1)) or rocuronium. The intubating dose of rocuronium (2 x ED95) was preceded 4 min earlier by saline, or a 0.1 x ED95 priming dose of rocuronium, atracurium, cis-atracurium, vecuronium or mivacurium. Intubating conditions were graded as excellent, good or poor with respect to laryngoscopy, vocal cord position and movement and reaction to intubation and/or cuff inflation. There were significant differences (P < 0.05) in laryngoscopy between suxamethonium and rocuronium primed with saline, atracurium or cis-atracurium. With respect to vocal cord position and movement during intubation, rocuronium without priming differed significantly from all other groups and for reaction to insertion of tracheal tube and/or cuff inflation. Rocuronium without priming differed significantly from all other groups except for rocuronium primed with itself. The mivacurium group showed more signs of pre-curarization than other groups (P < 0.05). There were significant differences between rocuronium alone and the other groups when final intubating conditions were compared. Priming rocuronium with 0.1 x ED95 of vecuronium, rocuronium, atracurium or cis-atracurium is a safe technique and did not increase risk of pre-curarization in healthy patients.

Intubating Conditions and Hemodynamic Changes during Tracheal Intubation with Propofol Followed by Remifentanil without the Use of Muscle Relaxant

Background: Studies have shown that tracheal intubation can be facilitated safely and effectively after induction of anesthesia with hypnotic and opioid without employing any muscle relaxants. Remifentanil is a new, ultra-short acting, selective mu-receptor agonist. The goal of our present study was to evaluate the appropriate induction dose of remifentanil with propofol for tracheal intubation without employing any muscle relaxants. Methods: We have assessed intubating conditions in three groups of 45 ASA I or II Patients. Each group received intravenous dosage of 2 mg/kg of propofol with remifentanil 1/kg (Group I), 2/kg (Group II) or 3/kg (Group III), respectively. No muscle relaxant was administered. Intubating conditions were assessed based on jaw relaxation, vocal cord position, vocal cord movement, airway reaction, and movement of limbs. Intubating conditions, mean arterial blood pressure and heart rate were measured just before induction (T00, baseline), before intubation (T0), 1 minute after intubation (T1), 2 minutes after intubation (T2) and 3 minutes after intubation (T3). Results: Intubating conditions were clinically acceptable in 26.7, 86.7 and 93.3% of patients, after 1, 2 or 3/kg administration of remifentanil, respectively. Clinically acceptable intubating conditions were significantly more in Group II and III when compared with Group I (P ＜ 0.05). Both HR (heart rate) and MAP (mean arterial pressure) were significantly lower in Group III when compared with Group I before intubation (T0), 1 minute after intubation (T1), 2 minutes after intubation (T2) and 3 minutes after intubation (T3) (P ＜ 0.05). Conclusions: We conclude that 2-3/kg of remifentanil may reliably provide 'good' to 'excellent' conditions for tracheal intubation when administered after administration of 2 mg/kg propofol. The conditions for intubation were significantly better in patients receiving 2 mg/kg of propofol followed by 2-3/kg of remifentanil than those receiving 1/kg of remifentanil.

Effects of Lidocaine Spray or Lidocaine IV on Endotracheal Intubation during Sevoflurane Inhalation Induction without Muscle Relaxants

Background: This study was designed to assess tracheal intubation without muscle relaxants, especially using 8 vol% sevoflurane. The study was designed to compare heart rate and blood pressure changes induced by a 10% lidocaine spray with that of 1% lidocaine IV and a control. Methods: Sixty patients, ASA I or II, undergoing various surgical procedures, were randomly assigned into three anesthetic pretreatment groups: Group I received routine vital capacity rapid induction with sevoflurane; Group II, inhalation induction with a 10% lidocaine spray 5 minutes before intubation; and Group III, inhalation induction with 1% lidocaine IV injection 2 minute before intubation. Intubating conditions were assessed as acceptable or unacceptable on the basis of a scoring system that depended on the ease of laryngoscopy, vocal cord position, and coughing after endotracheal tube insertion. Heart rate and blood pressure changes in each group were assessed before and after intubation. Results: The overall assessments of the intubating conditions were acceptable in 90%, 95%, and in 95% of patients in groups I, II, and III, respectively. Statistically, supplementing with a lidocaine intravenous injection or a pharyngolaryngeal lidocaine spray did not improve intubating conditions. Moreover, no differences in coughing after intubation, and no improvement in heart rate or in blood pressure changes were observed among the three groups. Conclusions: Sevoflurane inhalation induction without muscle relaxants offers satisfactory intubation, and heart rate and blood pressure changes without the use of lidocaine IV injection, or lidocaine.

The Effects of the Induction of Anesthesia and Tracheal Intubation with Sevoflurane on Blood Pressure, Heart Rate and BIS Value in Adults

Background: Sevoflurane permits the rapid induction and control of anesthetic depth, and its lack of pungency permits anesthesia to be induced by administering ti using a face mask. The goal of this study was to evaluate the possibility of induction and tracheal intubation without neuromuscular blocking drugs in adult patients given high inspired concentrations of sevoflurane (8 %). Methods: Fifty adult patients received 8% sevoflurane with nitrous oxide (2 L/min) and oxygen (2 L/min) by face mask until tracheal intubation. Patients exhaled to residual volume and deeply inspired the gas mixture following introduction. The time of response loss from introduction was noted as the induction time. The change of blood pressure, heart rate and bispectral index (BIS) value during induction and tracheal intubation were also determinated. Jaw relaxation, vocal cords position, and intubating response were used to assess intubation condition. Results: Mean time for induction of anesthesia was 42.4 4.7 seconds and mean time to acceptable intubating conditions was 300.5 32.7 seconds. The average BIS values at the time of induction and at the time of intubation were 79.3 22.0 and 23.8 10.6 respectively. The average time for a BIS value under 40 was 105.5 30.8 seconds. Systolic blood pressure, heart rate and BIS value were decrease significantly during the induction of anesthesia (P

外側輪状披裂筋牽引術 (岩村法)

Iwamura first reported Lateral cricoarytenoid muscle-Pull (LCA-Pull) for unilateral vocal cord paralysis in 1996. The lateral cricoarytenoid muscle is most important for vocal cord adduction. Treatment aims at reproducing natural adduction by pulling the lateral cricoarytenoid muscle. This result in the vocal fold being shifted medially and the difference in the vertical position being corrected. For surgical treatment of unilateral vocal cord paralysis, thyroplasty type I or fat injection has been indicated when the vertical vocal cord position is about the same and when distance between the vocal processes is short. Arytenoid adduction was employed when the vertical position is different. Both types of patient can be managed by LCA-pull, since the procedure leads to the reproduction of natural adduction. Another advantage is the simplicity of the surgical method, in which a small opening is made in the thyroid cartilage for traction and fixation of the lateral cricoarytenoid muscle. Consequently, the incidence of airway complications due to postoperative edema is low. Because the operation is done through the lamina of the thyroid cartilage, scarring due to previous cervical surgery won't be an additional factor in the level of surgical complication.

"Early" vocal cord laterofixation for the treatment of bilateral vocal cord immobility.

Vocal cord immobility (VCI) is commonly caused by a nonlaryngeal malignancy, thyroid surgery, or a presumed viral insult etc. The paralysis is often transient or temporary, thus the care of the patient should be optimized to avoid unnecessary diagnostic and therapeutic endeavours. This article reports on the result of the concept of early vocal cord laterofixation, which provides a minimally invasive solution to dyspnea in the critical early, potentially reversible, period of bilateral VCI. A prospective study of 25 consecutive patients (ages 33 to 81 years) who were diagnosed with a bilateral VCI. This condition had developed after thyroid surgery in 22 of the patients and after a blunt trauma of the neck in one case. In another case, a cricoarytenoid joint fixation was revealed, and aetiology remained unknown in one further patient. The surgical procedure was performed endoscopically with a modification of Lichtenberger's endo-extralaryngeal suture lateralization technique. The abducted vocal cord position was achieved by inserting a non-resorbable thread around the vocal process and tying on to the prelaryngeal muscles. Regular spirometric measurements and radiological aspiration tests were conducted on the patients. Adequate postoperative airway was achieved in all patients except one. Significant spontaneous vocal cord medialization was observed in two cases within a year and in three patients in the second and the third year. Partial or complete vocal cord recovery was observed in 17 cases. Further voice improvement followed in 9 patients when the threads were removed, due to vocal cord medialization or recovery. The mild postoperative aspirations ceased in the first postoperative days in all cases except one. The concept of "early" laterofixation satisfies the important criteria: it can provide an immediate and long-lasting adequate airway, and it can be considered potentially reversible from the point of view of laryngeal functions. Thus the procedure is a reliable primary treatment for bilateral VCI.

Endotracheal Intubation with Thiopental/Succinylcholine or Sevoflurane-Nitrous Oxide Anesthesia in Adults: A Comparative Study

Implications The three vital capacity inhaled anesthetic techniques with 8% sevoflurane and 66% N2O in O2 to receive 6% end-tidal sevoflurane may be an alternative for endotracheal intubation in adults who are at high risk from succinylcholine. We performed a double-blinded, prospective, randomized controlled trial to compare intubating conditions facilitated by succinylcholine or sevoflurane. One hundred twenty patients were randomized to receive either succinylcholine or sevoflurane for tracheal intubation. For the Succinylcholine group, patients were induced with thiopental 5 mg · kg−1 and tracheally intubated after administration of succinylcholine 1.5 mg · kg−1 IV. Patients receiving sevoflurane took three vital capacity breaths of 8% sevoflurane and 66% N2O in O2. At the loss of eyelash reflex, ventilation was assisted to establish end-tidal CO2 between 25–30 mm Hg, and intubation was performed when end-tidal sevoflurane was approximately 6%. Criteria of jaw relaxation, vocal cords position, and intubating response were used to assess intubation condition. If the intubation score was ≤6 of 12, it was described as acceptable, otherwise it was described as an unacceptable intubation condition. Tracheal intubation was successful in all patients. Intubator and observer blinded as to patient group judged that four patients (6.7%) in the Sevoflurane group and only one patient (1.7%) in the Succinylcholine group had an unacceptable intubation condition. However, there was no significant difference between groups (P > 0.05). Therefore, the three vital capacity breaths inhalation technique with sevoflurane may be an alternative for endotracheal intubation in adults.

Tracheal intubation of outpatients with and without muscle relaxants.

To compare intubating conditions and postoperative myalgias in outpatients after intubation with propofol/alfentanil compared with propofol/alfentanil/succinylcholine with and without precurarisation with d-tubocurarine. 144 ASA I-II ambulatory patients for dental extraction under anesthesia were studied. Subjects received either 3 mg d-tubocurarine (Group II) or saline (Groups I, III) i.v. prior to induction of anesthesia with 20 microg x kg(-1) alfentanil and 2.5 mg x kg(-1) propofol followed by 1.5 mg x kg(-1) succinylcholine (II and III) or saline 0.9% (I) for muscle relaxation. The ease of airway management and the postoperative incidence, severity and distribution of muscle pains were examined. Intubation was successful in all patients and there were no differences in jaw mobility, ease of bag-mask ventilation, visualization of the vocal cords or cord position. Limb movement was more common during intubation in Group I (37.5%) than in Group III (8.3%) or Group II (2%), P < 0.05. At home, VAS scores for myalgia were higher in Group III than in Group I and II. Neck myalgia was more common in Group II (72%) than in Groups II (44%) and I (41%), P < 0.05. Myalgias were also more common in Group III patients (P < 0.05). Acceptable intubating conditions were achieved with propofol and alfentanil alone. Succinylcholine reduced limb movement during intubation but was associated with postoperative myalgias for up to five days. Precurarisation with tubocurarine reduced the severity of succinylcholine myalgia.

Air swallowing in Rett syndrome

The possible causes of excessive swallowing of air leading to bloating, which is common in Rett syndrome (RS), were investigated during feeding and at rest. Seven individuals with RS aged between 4 and 33 years (three with air bloat) underwent feeding videoflouroscopy and concurrent respiration monitoring. The results were compared with a randomly selected group of 11 individuals, aged between 2 and 16 years, with quadriplegic cerebral palsy and feeding problems, some of whom had mild air bloat. All individuals from both groups had isolated pharyngeal swallows and several mouth breathed; this may account for some air swallowing but not the severe air bloat characteristic of RS. Thirty‐three individuals with RS aged between 3 and 44 years were monitored for nasal respiration, chest movements, swallowing, and vocal cord position at rest (between feeding). Twenty had air bloat, 17 of whom swallowed air during breath‐holding in the same way, and three gulped air during hyperventilation. Of the 13 without air bloat, eight did not have recurrent breath‐holding and five did, but without concurrent air swallowing. Several methods for reducing air swallowing in apnoea were investigated. The most successful was a dummy with an air leak, but this was poorly tolerated and could only be used for short periods of time. Apnoeas and air bloat are often worse when individuals are distressed and may in some individuals be reduced by anxiolytic medications.

Air swallowing in Rett syndrome

The possible causes of excessive swallowing of air leading to bloating, which is common in Rett syndrome (RS), were investigated during feeding and at rest. Seven individuals with RS aged between 4 and 33 years (three with air bloat) underwent feeding videoflouroscopy and concurrent respiration monitoring. The results were compared with a randomly selected group of 11 individuals, aged between 2 and 16 years, with quadriplegic cerebral palsy and feeding problems, some of whom had mild air bloat. All individuals from both groups had isolated pharyngeal swallows and several mouth breathed; this may account for some air swallowing but not the severe air bloat characteristic of RS. Thirty-three individuals with RS aged between 3 and 44 years were monitored for nasal respiration, chest movements, swallowing, and vocal cord position at rest (between feeding). Twenty had air bloat, 17 of whom swallowed air during breath-holding in the same way, and three gulped air during hyperventilation. Of the 13 without air bloat, eight did not have recurrent breath-holding and five did, but without concurrent air swallowing. Several methods for reducing air swallowing in apnoea were investigated. The most successful was a dummy with an air leak, but this was poorly tolerated and could only be used for short periods of time. Apnoeas and air bloat are often worse when individuals are distressed and may in some individuals be reduced by anxiolytic medications.

Airway complication after thyroid surgery: minimally invasive management of bilateral recurrent nerve injury.

After bilateral vocal cord paralysis, the consequent paramedian position usually necessitates tracheostomy for at least 6 months, when the paralysis is potentially reversible. In the present study a reversible endoscopic vocal cord laterofixation procedure was used instead of tracheotomy. Prospective study of 15 consecutive patients aged 33 to 73 years who suffered bilateral recurrent laryngeal nerve paralysis after thyroid surgery. The operation was performed endoscopically with a special endo-extralaryngeal needle carrier instrument. Two ends of a monofilament nonresorbable thread were passed above and under the posterior third of the vocal cord and knotted on the prelaryngeal muscles, permitting the creation of an abducted vocal cord position. If movement of one or both vocal cords recovered, the suture was removed. Regular spirometric measurements and radiological aspiration tests were conducted on the patients. During the follow-up period of 3 to 40 months, airway stability was demonstrated in all but one patient. After the repeated lateralization procedure, this patient's breathing improved. Partial or complete vocal cord recovery was observed in eight patients. In six patients further voice improvement was achieved when the threads were removed after vocal cord medialization or recovery. Mild postoperative aspirations ceased in the first postoperative days. This management approach offers an alternative to tracheostomy in the early period of paralysis, avoids terminal loss of voice quality, and provides a "one-stage" solution for permanent bilateral recurrent nerve injuries.

The complexity of tracheal intubation using rigid fiberoptic laryngoscopy (WuScope).

The complexity of tracheal intubation using rigid fiberoptic laryngoscopy (WuScope).

The Complexity of Tracheal Intubation Using Rigid Fiberoptic Laryngoscopy (WuScope)

The Complexity of Tracheal Intubation Using Rigid Fiberoptic Laryngoscopy (WuScope)

An external landmark for the anterior commissure.

The ability to predict the level of the true vocal cords based on external landmarks is crucial to the success of many laryngeal surgical procedures. This study examines the reliability of one such landmark on the thyroid cartilage. Twenty-four cadaver larynges were examined. A pin was placed through the landmark, best described as a small diamond shaped area of color change and surface depression along the anterior midline of each thyroid cartilage through which travels a very small unnamed artery. The endolaryngeal position of the pin was checked with a flexible nasopharyngoscope. In all 24 cadavers, the pin entered the larynx at the anterior commissure, just above or at the level of the true vocal cords. This external landmark reliably predicts the position of the true vocal cords. It serves as a useful adjunct to existing external landmarks used to direct thyroid cartilage cuts in laryngeal procedures.

Induction characteristics of thiopentone/suxamethonium, propofol/alfentanil or halothane alone in children aged 1-3 years

The aim of this study was to compare the effect of three different induction techniques, with or without neuromuscular block, on tracheal intubation, haemodynamic responses and cardiac rhythm. Ninety children, aged 1-3 years, undergoing day-case adenoidectomy were randomly allocated to three groups: group TS received thiopentone 5 mg kg−1 and suxamethonium 1.5 mg kg−1, group H 5 Vol.% halothane and group PA alfentanil 10 μg kg−1 and propofol 3 mg kg−1 for induction of anaesthesia. No anticholinergics were used. Holter-monitoring of the heart rate and rhythm was started at least 15 min before induction of anaesthesia and continued until 3 min after intubation. Tracheal intubation was performed by an anaesthetist blinded to the induction method and judged as excellent, moderate or poor according to ease of laryngoscopy, position of vocal cords and incidence of coughing after intubation. Tracheal intubation was successful at the first attempt in all children in groups TS and H and but only in 80% in group PA (P = 0.001). Intubating conditions were excellent in 22 (73%), 22 (73%) and one (3%) of the patients in groups TS, H and PA, respectively (P = 0.001). Cardiac dysrhythmias (supraventricular extrasystole or junctional rhythm) occurred in two (7%) patients in groups PA and H each (NS). Bradycardia occurred in 0 (0%), four (14%) and six (21%) children in groups TS, H and PA, respectively (P = 0.007 PA vs. TS, P = 0.03 H vs. TS). In conclusion, induction of anaesthesia with propofol 3 mg kg−1 and alfentanil 10 μg kg−1 without neuromuscular block did not provide acceptable intubating conditions in children 1-3 years, although it preserved arterial pressure better than thiopentone/suxamethonium or halothane. Cardiac dysrhythmias were few regardless of the induction method.

COMPARISON OF REMIFENTANIL WITH ALFENTANIL FOR INTUBATION IN ADULTS

S1 Alfentanil 50 mcg kg-1 has been shown to provide similar conditions for intubation compared with succinylcholine 1mg kg-1. Remifentanil is a new, potent opioid which has a rapid onset and due to rapid metabolism by plasma cholinesterase has a half life of only eight minutes. The aim of this study was to determine if an equipotent dose of remifentanil would provide the same intubating conditions as alfentanil 50mcg kg-1 compared with succinylcholine 1mg kg-1. METHODS: With IRB approval and informed written consent, 40 ASA 1 or 2 patients undergoing general anesthesia and elective orotracheal intubation were studied. All patients were premedicated with midazolam 0.03mg kg-1 iv. Routine monitoring was instituted and the patient preoxygented. Anesthesia was induced with propofol 2mg kg-1 and each patient was randomly allocated to one of three groups. Group S received succinylcholine 1mg kg-1, group A received alfentanil 50mcg kg-1 and group R remifentanil 2mcg kg-1. One minute after administering the preprepared study drug, a blinded anesthesiologist intubated the patient and scored the technique using a three point scale for the following criteria: jaw opening, ease of laryngoscopy, vocal cord position, vocal cord movement, ease of intubation, airway reaction and movement of limbs. Intubation conditions were scored overall as: 0) unable to intubate, 1) poor, 2) fair, 3) good and 4) excellent. Succinylcholine was given if intubation was not possible. Once the intubation had been scored the code was broken to allow the anesthetist to administer drugs appropriate for the remainder of the anesthetic. RESULTS: There was no difference in the demographic data between the three groups. More patients coughed in Group R (n=13), compared with group S (n=14), and A (n=13) (10, 1 and 3 respectively, P=0.0003, Fisher's exact test) and had vocal cord movement (6, 0 and 1 respectively, P=0.003). The number of patients who had intubating scores 3 and 4 in each group were; group S: 14, group A: 12, and group R: 3 (P=0.002,). CONCLUSIONS: Intubation conditions using remifentanil 2mcg kg-1 were significantly worse compared with alfentanil or succinyl choline. This was probably due to a rapid decrease in plasma concentration as a result of the rapid metabolism of remifentanil compared with alfentanil.

TRACHEAL INTUBATION WITHOUT NEUROMUSCULAR BLOCK IN PATIENTS WITH MYASTHENIA GRAVIS

S44 A wide range of sensitivities has been reported for patients with Myasthenia Gravis (MG) to neuromuscular blocking agents. It is difficult to estimate its proper induction dose and use antagonist. It has been reported that propofol may provide adequate conditions for intubation without the need for neuromuscular relaxants. This study was designed to assess intubating conditions with propofol and fentanyl without neuromuscular relaxant in patients with MG. PATIENTS AND METHODS: Hospital ethics committee approval was obtained to study 6 patients with MG aged 24-68 yr, scheduled for extended thymectomy. All patients were premedicated with midazolam 1.5-2.5 mg [center dot] kg-1 i.m. and atropine 0.5 mg [center dot] kg-1 i.m. 30min before anesthesia. Three minutes after administration of fentanyl 2 [micro sign]g [center dot] kg-1, a standard induction dose of propofol 2-3 mg [center dot] kg-1 was given over 30sec and Train-of-four-ratio (TOFR) of the adductor pollicis muscle by ulner nerve stimulation was measured (Table 2). Tracheal intubation was attempted 60sec after administration of propofol and three aspects of intubating conditions were assessed on a four-point scale (Table 1): ease of intubation, vocal cord position and degree of coughing on insertion of the tracheal tube.Table 2Table 1: Intubating condition scoreRESULTS: (Table 2) We found satisfactory intubating conditions in all patients. CONCLUSIONS: It was concluded that anesthesia induction with propofol 2-3 mg [center dot] kg-1 and fentanyl 2 [micro sign]g [center dot] kg-1 provided a satisfactory condition for tracheal intubation without neuromuscular relaxant in patients with MG.