Comparison of different doses of atracurium for quality of muscle relaxation during modified rapid sequence induction in emergency laparotomy: A prospective randomised double blind study

Background and Aims

In emergency and non-fasting patients posted for laparotomy under general anaesthesia, rapid sequence induction (RSI) is preferred, and it is routinely done by using succinylcholine or rocuronium. Using higher doses of atracurium [i.e. 3-4 times the 95% effective dose (ED95)] can provide acceptable intubating conditions in a short time. The primary objective of our study was to compare two different higher doses of atracurium to achieve good intubating conditions for RSI without using a priming dose. The secondary objective was to compare the duration of muscle relaxation using neuromuscular monitoring and haemodynamic responses during and after intubation.

Methods

Sixty patients were enroled and randomly assigned into two groups:-, group A1 (atracurium: 0.75 mg/kg) and group A2 (atracurium: 1 mg/kg). After premedication, anaesthesia was induced with propofol 2-2.5 mg/kg and atracurium injections, followed by intubation within a minute by trained anaesthesiologists. Meanwhile, intubating conditions, neuromuscular monitoring using train-of-four (TOF) measurements and post-tetanic-count and haemodynamics were recorded. Data were analysed statistically by using the Chi-square test and Student's t-test.

Results

Excellent intubation conditions (without coughing or bucking) were attained in 56.7% of cases in group A2 and in 13.3% in group A1 (P < 0.001). Duration of muscle relaxation, measured by time until TOF is two, was more prolonged in group A2 (79.2 ± 9.2 min) than in group A1 (60.13 ± 8.7 min, P < 0.001).

Conclusion

Acceptable intubating conditions can be achieved in a minute with the use of a high dose of atracurium (1 mg/kg) during RSI. Hence, atracurium can be used as an alternative drug for RSI.

Sample size considerations for studies comparing intubating conditions using quantitative monitoring versus a fixed interval during onset of neuromuscular blockade

INTRODUCTION

Data in the literature are still scarce to establish any recommendations on the use of quantitative monitoring during tracheal intubation.

PATIENTS AND METHODS

In this monocentric study, non-morbidly obese adult female patients without risk factors for difficult tracheal intubation were prospectively included. After 0.5 mg.kg^-1 atracurium during propofol-sufentanil anaesthesia, intubation conditions were evaluated using the Copenhague and Cormack-Lehane classification at the complete twitch suppression at the TOF to the AP (monitor group) or after a fixed 3 min waiting time after atracurium injection (3-min group). We also examined sample size for future studies.

RESULTS

We included 102 (monitor group) and 97 (3-min group) adult non-obese female patients without different characteristics. Intubation conditions were acceptable in 96/102 (94%) in the monitor group vs. 84/97 (87%) in the 3-min group, p = 0.07. The presence of a Cormack and Lehane view of 1 was marginally better in the monitor group as compared to the 3-min group, p = 0.041. We propose two possibility of sample size based on a difference of observed events based on acceptable intubation conditions, n = 602, or on excellent intubation conditions, n = 550.

DISCUSSION

This observational study shows that the use of a neuromuscular TOF monitoring of the ulnar nerve as compared to a fixed 3-min waiting time after atracurium injection could improve laryngoscopic view and show a tendency to better intubation conditions without conclusive statistical significance. We suggest that researchers consider our recommendations in terms of the sample size to include in their future research, keeping in mind the limitations of our study.

Application of Mivacurium in Fast-Track Anesthesia for Transthoracic Device Closure of Ventricular Septal Defects in Children

INTRODUCTION

The objective of this study was to investigate the effect of mivacurium in the application of fast-track anesthesia for transthoracic device closure of ventricular septal defects (VSDs) in children.

METHODS

The data of 108 children who underwent transthoracic device closure of VSDs from December 2018 to June 2020 were recorded and analyzed. All children were divided into group M (mivacurium group, n=55) and group C (cisatracurium group, n=53) according to the different muscle relaxant drug used.

RESULTS

No statistically significant differences in general preoperative data, intraoperative hemodynamic changes, or the incidence of adverse reactions were noted between the two groups (P>0.05). However, the intubation condition rating of children in group M was better than that in group C. The onset time, duration of clinical action and recovery index of the muscle relaxant, postoperative mechanical ventilation duration, and length of intensive care unit stay in group M were significantly lower than those in group C (P<0.05).

CONCLUSION

It is safe and feasible to use mivacurium as a muscle relaxant in children undergoing fast-track cardiac anesthesia during transthoracic device closure of VSDs.

Comparing the safety and efficacy of three different doses of atracurium in facilitating the insertion of laryngeal mask airway in patients undergoing phacoemulsification cataract surgery: A randomized clinical trial

Background

In this study, we aimed to evaluate the safety and efficacy of three different doses of atracurium on conditions of laryngeal mask airway (LMA) insertion, first-try success rate, and possible complications.

Materials and Methods

A total of 120 patient's ≥18 years old were randomly divided into three groups of 40. The study groups received fentanyl 2 μg/kg thiopental 5 mg/kg and atracurium in doses 0.2 mg/kg, 0.4 mg/kg, and 0.6 mg/kg, respectively, based on the patient group. The conditions of LMA insertion, hemodynamic responses, and complications were evaluated and compared in the groups.

Results

In the study groups, the LMA placement was difficult in 15%, 7.5%, and 2.5%, respectively (P = 0.13). There was no statistically significant difference among the groups regarding the success rate in the first attempt to the insertion of LMA. Of the three groups, 5%, 2.5%, and 2.5% had bleeding at the place of mask insertion (P = 0.77). 17.5%, 7.5%, and12.5% had sore throat, respectively (P = 0.4). No patient experienced laryngospasm during the study. Furthermore, changes in blood pressure, heart rate, and oxygen saturation were not significant in the three groups.

Conclusion

All three doses of atracurium have similar effects on the condition of LMA insertion. Atracurium 0.4 mg/kg accompanied by higher success on LMA insertion in the first attempt and lower airway complications (bleeding and sore throat), increasing this dose had no significant effect on the success rate of LMA insertion.

[Influence of different local anesthetics on atracurium neuromuscular blockade on rats]

INTRODUCTION

The association between Local Anesthetics (LAs) and Neuromuscular Blocking (NMB) drugs in clinical practice, and the possibility of interaction between these drugs has been investigated. LAs act on neuromuscular transmission in a dose-dependent manner and may potentiate the effects of NMB drugs.

OBJECTIVE

The aim of this study was to evaluate, in an experimental model, the effect of lidocaine and racemic bupivacaine on neuromuscular transmission and the influence on neuromuscular blockade produced by atracurium.

METHODS

Male Wistar rats, weighing from 250 g to 300g were used. The preparation was set up based on a technique proposed by Bülbring. Groups were formed (n = 5) according to the drug studied: lidocaine 20 μg.mL^-1 (Group I); racemic bupivacaine 5 μg.mL^-1 (Group II); atracurium 20 μg.mL^-1 (Group III); atracurium 20 μg.mL^-1 in a preparation previously exposed to lidocaine 20 μg.mL^-1 and racemic bupivacaine 5 μg.mL^-1, Groups IV and V, respectively. The following parameters were assessed: 1) Amplitude of hemi diaphragmatic response to indirect stimulation before and 60 minutes after addition of the drugs; 2) Membrane Potentials (MP) and Miniature Endplate Potentials (MEPPs).

RESULTS

Lidocaine and racemic bupivacaine alone did not alter the amplitude of muscle response. With previous use of lidocaine and racemic bupivacaine, the neuromuscular blockade (%) induced by atracurium was 86.66 ± 12.48 and 100, respectively, with a significant difference (p = 0.003), in comparison to the blockade produced by atracurium alone (55.7 ± 11.22). These drugs did not alter membrane potential. Lidocaine initially increased the frequency of MEPPs, followed by blockade. With the use of bupivacaine, the blockade was progressive.

CONCLUSIONS

Lidocaine and racemic bupivacaine had a presynaptic effect expressed by alterations in MEPPs, which may explain the interaction and potentiation of NMB produced by atracurium.

Determination of dose and efficacy of atracurium for rapid sequence induction of anesthesia: A randomised prospective study

Background and Aims:

Succinylcholine and high dose rocuronium are neuromuscular blocking agents commonly used for rapid sequence induction of anesthesia. Their usage is limited or contraindicated in some circumstances. The aim of this study is to determine the dosage and efficacy of atracurium without priming for rapid sequence induction of anesthesia.

Material and Methods:

One hundred fifteen surgical patients under general anesthesia were randomised into three groups. All patients were given 2-3 mg/kg propofol and 1 μg/kg fentanyl intravenously for the induction of anesthesia followed by different doses of atracurium (0.6 mg/kg, 0.75 mg/kg or 1 mg/kg) without a priming dose. Tracheal intubation was performed within one minute after the administration of the study drugs. The intubating conditions, vocal cord movement and diaphragm movement were graded as the primary endpoints. Statistical analysis was done using one-way analysis of variance (ANOVA) and Post Hoc tests.

Results:

Atracurium doses of 1 mg/kg, 0.75 mg/kg, and 0.6 mg/kg provided 51.4%, 43.6% and 26.3% success rates of intubation without coughing or bucking, respectively (P = 0.03). The intubating conditions were graded as excellent or good in 86.5% of the 1 mg/kg atracurium group patients and in 84.6% of the 0.75 mg/kg group patients (P < 0.05). An atracurium dose of 1 mg/kg facilitated significant differences in vocal cord and diaphragm paralysis compared with the dose of 0.6 mg/kg (P = 0.03).

Conclusion:

The administration of a relatively high dose of atracurium without priming can be used as an alternative neuromuscular blocking agent for rapid sequence induction of anesthesia in some circumstances.

[Effect of intraoperative warming on muscle relaxation recovery of cisatracurium in patients undergoing gastrointestinal surgery]

Objective: To investigate the effect of intraoperative warming on the postoperative relaxation recovery of cisatracurium in patients undergoing gastrointestinal surgery. Methods: Sixty ASA Ⅰ-Ⅱ patients, aged 20 to 60, undergoing elective gastrointestinal surgery in Cancer Hospital Chinese Academy of Medical Sciences from October, 2016 to March, 2019 were selected and they were randomly divided into two groups (n=30), N group and H group by random number table. N group was non-heat preserving group, and H group was heat preserving group. Tracheal intubation was induced by general anesthesia with cisatracurium 0.15 mg/kg, and the nasopharyngeal temperature were continuously monitored and recorded. Cisatracurium were infused 1-3 μg·kg(-1)·min(-1) by venous pump during operation with T1 at 1%-10% and stopped infusion 30 minutes before the end of surgery. The time when T1 recovered from 25% to 75%(muscle relaxation recovery index), and the time of T1 recovered to 25% to TOF ratios (TOFR, the ratio of the fourth muscle twitch height to T1 in TOF) recovery to 90% (full recovery time), cumulative drug use and surgery time were recorded. Results: There was no significant difference between the two groups in the cumulative drug dosage and operation time (P>0.05).The body temperature N group (35.7±0.2) ℃ was significantly lower than the H group (36.2±0.1) ℃ (t=13.940, P<0.01). The recovery index of N group (16.5±1.8) min was significantlyhigher than H group (10.5±2.1) min (t=12.094, P<0.01) and complete recovery time in N group (26.9±4.1) min was obviously longer than those in H group (15.0±2.9) (t=13.082, P<0.01). Conclusions: Patients with open gastrointestinal surgery are prone to hypothermia during surgery and heat protection is helpful to muscle relaxation recovery of cisatracurium.

ANESTHESIA OF AQUARIUM-HOUSED WALRUS ( ODOBENUS ROSMARUS): A CASE SERIES

  Walruses are a challenging species to anesthetize as a result of their large mass, limited access for drug delivery, unique physiology, and small number of reports describing anesthetic procedures. Three aquarium-housed walruses ( Odobenus rosmarus) ranging in age from 3 to 11 yr old (344-1,000 kg) were anesthetized for dental or ophthalmic surgical procedures, with one animal anesthetized twice and one anesthetized three times. Preanesthetic medication was with intramuscular midazolam (0.1-0.2 mg/kg) and meperidine (2-3 mg/kg). A catheter was placed in the extradural intravertebral vein, and anesthesia was induced with propofol to effect. Orotracheal intubation was performed and anesthesia maintained with isoflurane in oxygen using a circle breathing system connected to a ventilator. Intermittent positive pressure ventilation was used in all procedures. For the ophthalmic surgery, the neuromuscular blocking agent, cisatracurium, was given intravenously to provide a central eye and optimal surgical conditions. The neuromuscular block was antagonized with edrophonium. Total anesthesia times ranged from 1.5 to 6 hr. Midazolam and meperidine were antagonized with flumazenil and naltrexone, respectively, in five of six cases. Nonsteroidal anti-inflammatory agents were provided for analgesia. Recoveries were calm and uneventful. The described anesthetic protocols and case management were successful under the conditions encountered.

A Comparison Between the Hemodynamic Effects of Cisatracurium and Atracurium in Patient with Low Function of Left Ventricle who are Candidate for Open Heart Surgery

Background:

The need for muscle relaxants in general anesthesia in different surgeries including cardiac surgeries, and the type of relaxant to be used considering its different hemodynamic effects on patients with heart disease can be of considerable importance. In this study, the hemodynamic effects of two muscle relaxants, Cisatracurium and Atracurium in patients whit low function of left ventricle who are candidate for open heart surgery have been considered.

Method:

This study has been designed as a randomized prospective double-blind clinical trial. The target population included all adult patients with heart disease whose ejection fraction reported by echocardiography or cardiac catheterization was 35% or less before the surgery, and were candidate for open heart surgery in Shahid Rajaei Heart Center. Taking into account the inclusion and exclusion criteria, the patients were randomly placed in two groups of 30 people each. In the induction stage, all the patients received midazolam, etomidate, and one of the considered muscle relaxant, either 0.2 mg/kg of cisatracurium or 0.5mg/kg of Atracurium within one minute. In the maintenance stage of anesthesia, the patients were administered by infusion of midazolam, sufentanil and the same muscle relaxant used in the induction stage. The hemodynamic indexes were recorded and evaluated in different stages of anesthesia and surgery as well as prior to transfer to ICU.

Results:

In regard with descriptive indexes (age and sex distributions, premedication with cardiac drugs, ejection fraction before surgery, basic disease) there was no statistically significant difference between the groups.

Conclusions:

The significant difference of hemodynamic indexes between the two groups of this study, and the need for hemodynamic stability in all stages of surgery for patients with low function of left ventricle who are candidate for open heart surgery, proves that administering Cisatracurium as the muscle relaxant is advantageous and better.

Indolent Systemic Mastocytosis Manifesting as Protracted Anaphylactic Shock

Systemic mastocytosis is a rare disease due to abnormal proliferation of mast cells (MCs). A case of indolent systemic mastocytosis is presented here. After anesthetic induction for elective thyroid swelling with propofol and atracurium followed by endotracheal intubation, a 57-year-old female patient developed acute hypotension, sinus tachycardia, red rashes, increased airway pressure along with difficult ventilation, and desaturation. She developed multiorgan failure subsequently. MC tryptase level was persistently high. Bone marrow study revealed mastocytosis. She required antihistaminic, steroid, and organ support. With treatment, organ functions recovered gradually. Atracurium precipitated anaphylactic shock causing severe morbidity in this patient.

Effect of Low-dose Atracurium on Laryngeal Mask Airway Insertion Conditions: A Randomized Double-blind Clinical Trial

Background:

The amount of sedation and muscle relaxation of the jaw may have an impact on complications caused by laryngeal mask airway (LMA). The aim of this study is to evaluate the effect of low-dose Atracurium on conditions of insertion, complications, and hemodynamic responses to LMA insertion following induction of anesthesia with propofol, in patients undergoing cataract surgery.

Patients and Methods:

In this double-blind randomized clinical trial study, 60 patients were randomly divided into two groups. Initially, the patients in the study group received 0.15 mg/kg intravenous injection of atracurium, and the patients in the control group received 2 ml of intravenous injection of normal saline, after which anesthesia in both groups were induced with midazolam, fentanyl, lidocaine, and propofol. The amount of jaw relaxation, ease of insertion, and the time needed for insertion, hemodynamic responses and complications of LMA insertion were evaluated.

Results:

Jaw relaxation and ease of LMA insertion in the study group was significantly better than that of the control group (P = 0.02). Average time needed for LMA placement in the study group (5/06 ± 0.52 second) was significantly lower than the control group (5/76 ± 0.67 second) (P = 0.001). Hemodynamic response to LMA insertion was similar in both groups. Sore throat at recovery and 24 h after surgery in the control group was significantly higher than that of the study group (3/30 vs. 10/30) (P = 0.01).

Conclusions:

Using low doses of atracurium decreases the time needed for LMA insertion and sore throat after the operation. Atracurium also increases jaw relaxation and facilitates the placement of LMA.

[Effect of cisatracurium on entropy index of children undergoing sevoflurane anesthesia]

Objective: To investigate the effect of cisatracurium on entropy index of children undergoing sevoflurane anesthesia. Methods: Forty-five child patients (ASAⅠ-Ⅱ) who underwent cleft lip and palate repair surgery in Beijing Stomatological Hospital were selected from June to November in 2015. They aged from 8 to 24 months and were randomly divided into 3 groups, as well as maintained at different end-tidal sevoflurane concentrations (C(ET)Sev), respectively. The C(ET)Sev in Group Ⅰ was 2.5%, with a total number of 15 cases. The C(ET)Sev in Group Ⅱ was 3.0%, with a total number of 16 cases. The C(ET)Sev in Group Ⅲ was 3.5%, with a total number of 14 cases. After the child patients were sent into operating room, their ulnar nerves underwent train-of-four stimulation (TOF) inspection using Datex-Ohmeda anesthesia workstation. The four muscle twitches orderly occurring on abductor pollicis muscle were recorded as T(1,)T(2,)T(3) and T(4,)respectively. The level of state entropy (SE) and reactive entropy (RE) was monitored by the entropy index module. 6% of sevoflurane high-flow inhalation was used to induce children's sleep, and the oxygen flow was adjusted to 2 L/min. Also, the C(ET)Sev in 3 groups maintained at 2.5%, 3.0% and 3.5%, respectively, which lasted for more than 10 min. Then, they were administered with 0.15 mg/kg cisatracurium, and the level of SE and RE in 3 groups was recorded when they were before the drug delivery of cisatracurium (t(1)), 50% inhibition of T(1) (t(2)), 75% inhibition of T(1) (t(3)) and 100% inhibition of T(1) (t(4)), respectively. Results: At the time of t(1,)t(2,)t(3) and t(4,)the SE values in Group Ⅰ were (55±19), (53±20), (48±18) and (43±16), respectively, and the differences were statistically significant (F=3.881, P<0.05). The SE values in Group Ⅱ were (42±19), (41±21), (39±18), (31±13), and the differences were statistically significant (F=3.463, P<0.05). The SE values in Group Ⅲ were (34±11), (33±16), (33±14) and (32±13), respectively. The differences were not statistically significant (F=0.162, P>0.05). At the time of t(1,)t(2,)t(3) and t(4,)the RE values in Group Ⅰ were (54±13), (48±11), (34±13) and (30±13) respectively, and the differences were statistically significant (F=36.975, P<0.01). The RE values in Group Ⅱ were (43±13), (38±13), (33±12) and (28±11) respectively, the differences were statistically significant (F=12.438, P<0.01). The RE values in Group Ⅲ were (34±10), (33±11), (31±12) and (25±11) respectively, and the differences were statistically significant (F=6.019, P<0.01). The RE values of child patients in Group Ⅰ, Ⅱ and Ⅲ decreased after the drug delivery of cisatracurium. Conclusion: The muscle relaxants (cisatracurium) will decrease the entropy index of children undergoing sevoflurane anesthesia, but will not affect their SE values under deep anesthesia.

Comparison of atracurium and methocarbamol for preventing succinylcholine-induced muscle fasciculation: A randomized controlled trial

Fasciculation is a minor adverse effect of succinylcholine and may be an unpleasant experience for patient. The aim of this study was to compare the use of atracurium and methocarbamol to decrease the occurrence and severity of succinylcholine-induced muscle fasciculation. Fifty-nine adults with American Society of Anesthesiologists I or II hospitalized for elective surgery were randomly assigned to two groups: Group A (n = 29) who received succinylcholine 1 mg/kg body weight (BW) intravenously followed by 0.2–0.5 mg/kg BW atracurium and patients in Group B (n= 29) who received succinylcholine 1 mg/kg BW intravenously followed by methocarbamol 0.2–0.5 mg/kg BW. Anesthesia was induced in all patients with thiopental sodium 3–5 mg/kg. Fasciculation was scored on a four-point (0–4) Likert scale. There were no statistically significant differences in demographic variables between two groups, whereas in Group A, 27 patients (93.1%) suffered from mild fasciculation and two (6.9%) from moderate fasciculation. In Group B, twenty patients (68.9%) suffered from mild fasciculation, five (17.2%) from moderate fasciculation, and four (13.9%) from severe fasciculation. The difference between the groups was statistically significant (P < 0.05). Atracurium is more effective than methocarbamol in decreasing the occurrence and severity of succinylcholine-induced fasciculations. In addition, the use of methocarbamol before succinylcholine administration can decrease the incidence of severe fasciculation.

Effects of avoiding neuromuscular blocking agents during maintenance of anaesthesia on recovery characteristics in patients undergoing craniotomy for supratentorial lesions: A randomised controlled study

Background and Aims:

Neuromuscular blocking agents have been one of the cornerstones of anaesthesia. With the advent of newer surgical, anaesthetic and neurological monitoring techniques, their utility in neuroanaesthesia practice seems dispensable. The aim of this prospective, comparative, randomised study was to determine whether neuromuscular blocking agents are required in patients undergoing supratentorial surgery when balanced anaesthesia with desflurane, dexmedetomidine and scalp block is used.

Methods:

Sixty patients with the American Society of Anesthesiologists physical status I or II, aged between 18 and 60 years were included in the study. All patients received anaesthesia including desflurane, dexmedetomidine and scalp block. The patients were randomly allocated to receive no neuromuscular blocking agent (Group A) or atracurium infusion to keep train-of-four count 2 (Group B). The two groups were compared with respect to haemodynamic stability, brain relaxation scores and recovery characteristics. Haemodynamic parameters and time taken to achieve Aldrete score >9 and other secondary outcomes were analysed using Student's t-test. Non-parametric data were analysed using the Mann–Whitney test.

Results:

The mean arterial pressure was comparable between the groups. The intraoperative heart rate was comparable; however, in the post-operative period, it remained higher in Group B for 30 min after extubation (P = 0.02). The brain relaxation scores were comparable among the two groups (P = 0.27). Tracheal extubation time, time taken for orientation and time required to reach Aldrete score ≥9 were comparable among the two groups.

Conclusion:

The present study suggests that balanced anaesthesia using desflurane, dexmedetomidine and scalp block can preclude the use of neuromuscular blocking agents in patients undergoing supratentorial surgery under intense haemodynamic monitoring.

The effect of defasciculating doses of pancuronium and atracurium on succinylcholine neuromuscular blockade

Background:

A defasciculating dose of non-depolarizing muscle relaxant administered prior succinylcholine decrease its side effects including fasciculations and postoperative myalgias; however it is believed that the dosage of succinylcholine should be increased when such a pre-treatment is used.

Objectives:

We hypothesized that a defasciculating dose of pancuronium as a pre-treatment could prolong its duration of effect.

Patients and Methods:

Forty patients scheduled for elective orthopaedic surgery were consecutively assigned into 5 groups, a first group without pre-treatment (succinylcholine 1 mg/kg) and 4 subsequent groups of pretreatment with atracurium 0.05 mg/kg + succinylcholine 1 or 1.5 mg/kg and pancuronium 7.5 µg /kg + succinylcholine 1 and 1.5 mg/kg. The muscle relaxant effect of succinylcholine was assessed with a force transducer using train of four stimulations every 12 seconds. Kruskall Wallis Anova test was used to compare results.

Results:

The duration of succinylcholine induced paralysis (1 and 1.5 mg/kg) was significantly prolonged with pre-treatment with pancuronium but succinylcholine 1mg/kg did not reached maximum blockade after pre-treatment with atracurium. After pancuronium, full recovery after succinylcholine 1.5 and 1 mg/kg occurred respectively after 18 and 15 minutes. P < 0.05 vs. 12 minutes for succinylcholine 1mg/kg alone.

Conclusions:

This study highlights potentiation effect of a defasciculating dose of pancuronium on succinylcholine paralysis suggesting the lack of justification to increase succinylcholine dosage.

Effects of pretreatment with different neuromuscular blocking agents on facilitation of intubation with rocuronium: A prospective randomized comparative study

BACKGROUND AND AIMS

Priming principle refers to administration of a small dose of non-depolarising blocker, which when followed by a large intubating dose produces a relatively rapid and profound blockade to ensure suitable conditions for endotracheal intubation. We aimed to compare the effects of rocuronium, vecuronium, and atracurium as "pretreatment" drugs on intubating conditions with rocuronium facilitated endotracheal intubation.

METHODS

This double-blinded, randomised controlled prospective study was carried out at a tertiary health care hospital on patients undergoing surgical procedures under general anaesthesia. They were randomly allocated into three groups (n = 35) by computer generated randomisation chart to receive either rocuronium (0.06 mg/kg body weight) (Group A); vecuronium (0.01 mg/kg body weight) (Group B) or, atracurium (0.05 mg/kg body weight) (Group C), followed by intubating dose (0.6 mg/kg body weight) of rocuronium. The haemodynamic parameters and intubating conditions were studied and statistically analysed by ANOVA test and Student's t-test as applicable using statistical package for the social sciences 16.0 for windows (SPSS Inc., Chicago, IL, USA).

RESULTS

Excellent intubating conditions were noted in maximum number of patients in Group C (97.41%). No significant differences were observed in the systolic blood pressure in all the three groups at all-time intervals. The mean arterial pressure rose significantly from baseline value to maximum, at '0' min in all the groups; however, no significant difference was observed amongst the groups (P > 0.05).

CONCLUSION

Pretreatment with rocuronium bromide can facilitate endotracheal intubation in 60 s irrespective of non-depolarising muscle relaxants used for priming; however, it cannot attenuate haemodynamic changes associated with laryngoscopy and intubation.

Gender determines the effect of atracurium priming technique in a randomized study

Objective: To evaluate the effect of priming atracurium over onset time and intubating time of general anesthesia between different genders.

Methodology: Sixty-six male and sixty-four female patients, ASA I-II, aged 18-65 years, were randomly divided into four groups: group M₁: male patients with saline priming; group M₂: male patients with priming atracurium dose of 0.05 mg/kg; group F₁: female patients with saline priming; group F₂: female patients with priming atracurium dose of 0.05 mg/kg. General anesthesia was induced with midazolam(0.1 mg*kg^-1) propofol(0.75 mg*kg^-1), intubation dose of atracurium (0.5 mg*kg^-1), fentanyl (3 μg*kg^-1). The incidences of dizziness, diplopia, heavy eyelids and dyspnea were observed. Neuromuscular tension was quantified by using TOF-Guard neuromuscular monitor, and intubating time was defined as the duration from the infusion of intubation dose of atracurium to the time when T4/T1=0.

Results: The intubating time of group F2 was shorter than that of group F1. There was no significant difference between group M1 and group M2. The incidences of dizziness, diplopia and heavy eyelids in group F2 were higher than those in group M2.

Conclusion: Atracurium priming technique could shorten the intubation time of female patients, but not for male patients, and the gender plays a key role in affecting the clinical outcome of atracurium priming.

Anesthetic experience using total intravenous anesthesia in a patient with Isaacs' syndrome -A case report-

We report on an anesthetic experience with a 74-year-old female with Isaacs' syndrome, who underwent elective surgery for open rotator cuff repair. Isaacs' syndrome is a rare peripheral motor neuron disorder with clinical manifestations such as involuntary muscle twitching, cramps, mild weakness and increased sweating. To avoid prolonged neuromuscular blockade, the patient was observed with neuromuscular monitoring during total intravenous anesthesia with propofol, remifentanil, and atracurium. No adverse events were observed during the anesthetic management, and the patient recovered smoothly from the neuromuscular blockade. We describe the clinical characteristics of Isaacs' syndrome and its specific considerations in anesthesia.

Postoperative residual block in postanesthesia care unit more than two hours after the administration of a single intubating dose of atracurium

BACKGROUND

Residual neuromuscular blockade continues to be a clinical problem after surgical procedures. The purpose of this study was to determine the incidence of residual paralysis in the postanesthesia care unit (PACU) after a single intubating dose of twice of the 95% estimated dose (ED95) of a nondepolarizing muscle relaxant with an intermediate duration of action.

METHODS

Two hundred and sixteen patients scheduled for elective surgery under general anaesthesia requiring tracheal intubation were included in the study. They received a single intubating dose of intravenous atracurium (0.5 mg/kg) to facilitate tracheal intubation. At the end of surgery, if train of four (TOF)-ratio was ≤ 0.9, neostigmine 40 μg/kg intravenously was given. If TOF-ratio was ≥ 0.9, no neostigmine was given. Also, in awake patients with TOF > 0.9, residual neuromuscular paralysis was evaluated by using clinical tests such as head lift test and tongue depressor test.

RESULTS

TOF was less than 0.9 in 48 (22.2%) patients while after 120 minutes, no patients had TOF less than 0.9. Of 33 patients whose operation lasted less than 120 minutes, 4 patients had TOF less than 0.9 at the end of surgery. There was no case of hypoventilation or hypoxia at PACU. The incidence of negative value in clinical tests was high.

CONCLUSIONS

Our study gave the impression that more than two hours between the administration of a single intubating dose of an intermediate-acting nondepolarizing muscle relaxant (atracurium) and arrival to the PACU can probably guarantee the lack of a residual paralysis.

Effect of cisatracurium versus atracurium on intraocular pressure in patients undergoing tracheal intubation for general anesthesia

BACKGROUND

Increase in intraocular pressure (IOP) following tracheal intubation during general anesthesia can be troublesome. We compared the influence of two muscle relaxants, cisatracurium and atracurium, on IOP in patients undergoing general anesthesia.

METHODS

This randomized, double-blind, comparative trial was conducted on 90 candidates for elective non-ophthalmic surgery under general anesthesia. Patients were 18 to 60 years old with the American Society of Anesthesiologists (ASA) class of I or II. Anesthesia was induced with fentanyl (1.5 mg/kg) and sodium thiopental (5 mg/kg). Patients received atracurium (0.5 mg/kg) or cisatracurium (0.15 mg/kg) two minutes prior to tracheal intubation. IOP, systolic (SBP) and diastolic blood pressure (DBP), and heart rate (HR) were measured at baseline (before medication), after medication (before intubation), and 2, 5, and 10 minutes after intubation.

RESULTS

In both groups IOP decreased after administration of muscle relaxants (-3.3 ± 3.6 mmHg), then increased 2 minutes after intubation (5.5 ± 4.4 mmHg), but decreased 5 (-3.3 ± 3.3 mmHg) and 10 (-0.5 ± 2.6 mmHg) minutes after intubation. IOP and SBP were significantly higher in the atracurium compared with the cisatracurium group after 2 (p < 0.001 and 0.002, respectively), 5 (p < 0.001 and 0.012, respectively), and 10 (p = 0.02 and 0.048, respectively) minutes after intubation.

CONCLUSIONS

Compared with atracurium, administration of cisatracurium can better prevent the increase of IOP following tracheal intubation in general anesthesia. The observed difference might be related to different effects on hemodynamic variables. Application of these results in patients under ophthalmic surgery is warranted.

Total intravenous anesthesia with propofol and remifentanil in a patient with MELAS syndrome -A case report-

A 23-year-old woman with MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes) underwent a laparoscopy-assisted appendectomy. MELAS syndrome is a multisystemic disease caused by mitochondrial dysfunction. General anesthesia has several potential hazards to patients with MELAS syndrome, such as malignant hyperthermia, hypothermia, and metabolic acidosis. In this case, anesthesia was performed with propofol, remifentanil TCI, and atracurium without any surgical or anesthetic complications. We discuss the anesthetic effects of MELAS syndrome.

Sub-tenon atracurium injection in rabbit eyes;a histopathologic study

PURPOSE

To evaluate early and late histopathologic changes following posterior sub-Tenon injection of atracurium in the rabbit eye.

METHODS

This study was performed on 39 healthy white New Zealand rabbits which received sub-Tenon injection of 0.05-0.08 mg/kg atracurium diluted in 0.5 ml normal saline (N/S) in the left and 0.5 ml N/S in the right eyes. Bilateral enuclation was performed one hour after the injection to evaluate early changes in 19 rabbits and one week later to determine late changes in the remaining 20 animals. After enucleation, the rabbits were euthanized. Enucleated eyes were sent in 10% formalin solution for histopathologic examination. After processing, the specimens were evaluated by light microscopy following staining with hematoxylin and eosin, and trichrome.

RESULTS

Congestion was more common in the control group 1 hour after injection.Liquifaction necrosis was seen in both groups but was significantly increased one week after the injection in the atracurium group.

CONCLUSION

Congestion is a transient complication related to injection which disappears after one week, but necrosis seems to be an important late complication of atracurium injection.