Administration Of Atracurium Research Articles

Pharmacokinetics study of atracurium, dexmedetomidine, midazolam and 1-hydroxymidazolam in patients undergoing acute aortic dissection surgery.

An UPLC-MS/MS method was developed and validated for simultaneous determination of atracurium (ATC), dexmedetomidine (DEX), midazolam (MDZ) and 1-hydroxymidazolam (1-OH-MDZ) and the pharmacokinetics of ATC, DEX, MDZ and 1-OH-MDZ in patients undergoing aortic dissection surgery were investigated. The analytes were extracted by acetonitrile precipitation and separated on an Acquity UPLC BEH C18 column (2.1mm × 50mm, 1.7μm) with a mobile phase of acetonitrile-0.1% formic acid and a gradient mode. In the positive ion mode, the following mass transition pairs were monitored by multiple reaction monitoring (MRM) for the four analytes and IS: m/z 385.1→206.2 for ATC, m/z 201.2→95.1 for DEX, m/z 326.1→291.1 for MDZ, m/z 341.9→324.0 for 1-OH-MDZ, and 284.9→153.9 for diazepam (IS). Seven male patients undergoing aortic dissection surgery received general anesthesia and intravenous administration of ATC, DEX, and MDZ during the surgery. Venous blood was collected at different time points at the end of surgery and after surgery. The concentrations of ATC, DEX, MDZ, and 1-OH-MDZ were detected, and the pharmacokinetic parameters were calculated. The method showed good linearity for each analyte. The inter-batch precision ranged from 1.37% to 9.87% and the intra-batch precision ranged from 2.41% to 10.72%; the accuracy ranged from 94.33% to 104.51%. Finally, the matrix effect, extraction recovery and stability data met the FDA recommended acceptance criteria for validation of bioanalytical methods. The t1/2 of ATC, DEX, MDZ and 1-OH-MDZ was (6.74 ± 2.27) h, (9.55 ± 4.93) h, (10.17 ± 5.35) h, and (6.90 ± 2.38) h, the Cmax, of ATC, DEX, MDZ and 1-OH-MDZ was (1054.20 ± 202.37) ng/mL, (1.93 ± 1.07) ng/mL, (1256.57 ± 389.09) ng/mL, and (1034.39 ± 292.92) ng/mL in patients undergoing aortic dissection surgery, respectively. The developed UPLC-MS/MS method for simultaneous determination of ATC, DEX, MDZ and 1-OH-MDZ in patient plasma was accurate, reproducible, specific. After continuous administration of ATC, DEX, and MDZ to patients undergoing surgery for acute aortic dissection, the pharmacokinetics of ATC, DEX, MDZ and 1-OH-MDZ in patients undergoing aortic dissection surgery were studied.

Prolonged Apnoea after Succinylcholine and Atracurium Administration

Prolonged Apnoea after Succinylcholine and Atracurium Administration

Onset and duration of action of escalating doses of atracurium in anesthetized healthy goats

ObjectiveThe aim of this study was to describe the onset and duration of action of escalating doses of atracurium in healthy, anesthetized goats. Study designRandomized, blinded, triple crossover study.Animals A total of eight (five males and three females) healthy goats weighing 42.7–123.5 kg and aged from 11 months to 8 years. MethodsGoats were anesthetized three times with propofol and anesthesia was maintained with isoflurane. One of three doses of atracurium was administered intravenously 30 minutes after induction: 0.25 mg kg–1 (AT25), 0.5 mg kg–1 (AT50) or 0.75 mg kg–1 (AT75). Acceleromyographic train-of-four ratio (TOFR) followed by train-of-four counts (TOFC) were recorded at 30 second intervals after atracurium administration to determine blockade onset (TOFC = 0). The TOFR followed by TOFC were recorded at 5 minute intervals until return to pre-atracurium baseline (TOFR = 1.0). Normally distributed data were analyzed with repeated measures anova and a Tukey multiple comparison test. Data not normally distributed were analyzed with a Friedman test and a Dunn’s multiple comparison test. ResultsFor AT50 and AT75, 100% of goats achieved TOFC = 0 after atracurium administration. For AT25, however, 87.5% of goats achieved TOFC = 0 after atracurium administration. The onset time was shorter for AT75 [1.5 (0.5–1.5) minutes; median (range)] than for AT25 [2 (1–4) minutes] (p = 0.048). The duration of action [from onset time to complete reversal (TOFR = 1.0)] was significantly shorter for AT25 (52 ± 12 minutes, mean ± SD) than for AT50 (77 ± 18 minutes) (p < 0.001) and AT75 (85 ± 16 minutes) (p < 0.001). There was no significant difference in duration between AT50 and AT75 (p = 0.238). Conclusions and clinical relevanceDoses of 0.5 and 0.75 mg kg–1 atracurium may produce complete neuromuscular blockade in healthy, anesthetized goats.

The effect of dexmedetomidine on wake-up test quality when muscle relaxants are not used: A randomized control trial.

Stagnara wake-up test is a simple reproducible neuromonitoring method during spinal surgery which replaces the evoked potential monitoring in the absence of neuromonitoring facilities. Dexmedetomidine (DEX) effect on the intraoperative wake-up test is still unclear. The present study was conducted to evaluate the effectiveness of DEX on the quality of wake-up test during spinal correction surgery. A randomized controlled study was carried out over 62 patients randomized into two equal groups planned for elective minimally invasive corrective spine surgery. Instead of atracurium administration in the control group, patients in the experimental group were administered titrated continuous intravenous infusion of DEX at a dose of 0.2-0.7 μg/kg/hour. Lidocaine 2% spray around the vocal cords was done in both the groups to facilitate toleration of the endotracheal tube. The DEX group showed statistically significant longer duration and better quality of the wake-up test. Statistically significant better haemodynamic state, a lower amount of intraoperative sedatives and higher amount of intraoperative analgesics were also evident in the DEX group. The postoperative Ramsay sedation scale was significantly lower in the DEX group just after extubation. The DEX use has shown an improving effect on the wake-up test quality, with slightly prolonged wake-up time. The present work supports the use of DEX as an adjuvant drug alleviating the need for the neuromuscular blockade, inducing a better haemodynamic profile, exhibiting better sedation and improving the awakening condition.

A suspected non‐allergic anaphylactic reaction to intravenous administration of atracurium in a dog

AbstractHypersensitivity reactions are rare events but have the potential to be life‐threatening. They are relatively more common during general anaesthesia. This is potentially due to multiple drugs being administered concurrently. An 8‐year‐old, female neutered Labrador Retriever with bilateral cataracts was anaesthetised for right phacoemulsification. Soon after atracurium administration, the patient's heart rate (HR) increased, alongside decreases in arterial blood pressure and end tidal carbon dioxide (ETCO2). The dog was treated with clorphenamine and ephedrine intravenously (IV), while receiving a crystalloid fluids bolus. After 20 minutes both HR and blood pressure normalised, and the remainder of anaesthesia and recovery were uneventful. We suspected a non‐allergic anaphylactic reaction to atracurium.

Anaphylactic Shock Due to Atracurium in a Patient Underwent General Anesthesia

BACKGROUND: Anaphylaxis is a systemic hypersensitivity reaction marked by life-threatening, rapid onset of the airway, breathing, and circulation problems. Despite its rare incidence, without proper treatment, it may cause fatality.&#x0D; CASE REPORT: In this report, we present a 19-year-old female with an infected ovarian cyst, who was scheduled for gynecologic laparotomy. In pre-operative assessment, she was classified as an American Society of Anesthesiologist (ASA) one patient without any history of drug or food allergy. Hemodynamic changes occurred on anesthesia induction after the administration ofatracurium, a muscle relaxant agent. Marked clinical signs were wheezed-bronchospasm, dyspnea, hypersalivation, desaturation, tachycardia, hypotension, and systemic erythema. She was diagnosed with anaphylactic shock. We provided 100% oxygenation, fluid resuscitation, epinephrine, and supportive therapy by anaphylaxis guidelines. Respiratory and cardiovascular functions stabilized 2 h post-resuscitation. The surgery was canceled, and she was observed in ICU for 24 h.&#x0D; CONCLUSION: Timely diagnosis and early resuscitation are key factors determining the outcome of an anaphylactic reaction.

Effects of two levels of partial neuromuscular block with atracurium on the ventilatory response to hypercapnia in anesthetized Beagles.

OBJECTIVE To evaluate effects of 2 levels of partial neuromuscular block on the ventilatory response to a hypercapnic challenge in anesthetized dogs and to evaluate effects of edrophonium for reversing partial neuromuscular block. ANIMALS 6 healthy adult Beagles. PROCEDURES Each dog was anesthetized twice with propofol and dexmedetomidine. End-tidal partial pressure of CO2 (Petco2), tidal volume (Vt), and peak inspiratory flow (PIF) were measured during breathing at rest. Maximal Vt and PIF (VtMAX and PIFMAX, respectively) in response to a hypercapnic challenge consisting of 10% CO2 inhaled for 1 minute were measured. Variables were measured before administration of atracurium (baseline), during moderate (train-of-four [TOF] ratio, 0.3 to 0.5) and mild (TOF ratio, 0.6 to 0.8) atracurium-induced neuromuscular block, and after neuromuscular block recovery (TOF ratio, ≥ 0.9) following administration of edrophonium or saline (0.9% NaCl) solution. Dogs for which any variable returned to < 80% of the baseline value were identified. RESULTS Partial neuromuscular block increased Petco2; it impaired Vt at rest and VtMAX but not PIF at rest and PIFMAX. All variables except Petco2 returned to baseline values when the TOF returned to ≥ 0.9. After recovery from neuromuscular block, significantly more dogs had a VtMAX < 80% of the baseline value when edrophonium was not administered. CONCLUSIONS AND CLINICAL RELEVANCE Partial neuromuscular block in anesthetized Beagles decreased spontaneous ventilation at rest and impaired the response to a hypercapnic challenge. Response to hypercapnic challenge might remain partially impaired after recovery of the TOF ratio to ≥ 0.9.

Effect of magnesium sulfate infusion on sevoflurane consumption, hemodynamics, and perioperative opioid consumption in lumbar disc surgery

Magnesium sulphate administration was initially reported to reduce postoperative analgesic requirements. Subsequent reports, though, were inconsistent. Specifically, we tested the hypotheses that intraoperative magnesium sulfate administration reduces postoperative requirement for opioids, secondary outcomes were intraoperative muscle relaxant, sevoflurane consumptions and postoperative pain. Fifty American society of anesthesiology status (ASA) I-II patients who gave a written informed consent were scheduled for elective lumbar disc surgery. The Institutional Review Board approved the study. Patients were randomly assigned to the placebo group (n = 25) or magnesium group (n = 25). Patients assigned to the magnesium group were given an initial infusion of 30 mg/kg (over 10 minutes) starting immediately after anesthesia and completed before intubation. The infusion was then continued at 10 mg/kg/hr throughout surgery. General anesthesia was induced with propofol, 2.5 mg/kg, and maintained with sevoflurane 2 percent in a 50 percent O2/50 percent N2O mixture. The sevoflurane concentration was adjusted to keep bispectral index (BIS) values between 45 and 60. Both groups were given atracurium, 0.6 mg/kg, and a remifentanil infusion at an initial dose of 0.1 mg/kg/h. The remifentanil infusion was adjusted to maintain heart rate and mean arterial pressure (MAP) within 20 percent of baseline values. Atracurium administration was repeated when the train of four (TOF) ratio exceeded 0.30. Intubation conditions were scored. At the end of surgery, the authors assessed recovery using early recovery criteria and Aldrete recovery scores. Postoperative analgesia was maintained with morphine via patient-controlled analgesia. Heart rate, MAP and pulse oximetry (SPO2) values were similar in the groups at all times. Intubating conditions were similar except that the increase in MAP was greater in the placebo group. Neither BIS values nor sevoflurane consumption differed between the groups; however, significantly less atracurium [95% CI = 4.1 (2.8, 5.5)] and remifentanil [95% CI = 0.14 (0.07, 0.20)] was used in the magnesium group. Side effects, Aldrete scores, and early recovery parameters were all similar in the groups. In the first 24 hours, visual analogue scale (VAS) values for pain were greater in the placebo than in the magnesium group. The magnesium group consumed significantly less morphine [95% CI = 11 (6, 16)]. Intraoperative magnesium administration significantly reduced muscle relaxant and opioid requirements; more importantly, it also reduced postoperative pain and opioid use.

Diabetes mellitus does not affect the neuromuscular blocking action of atracurium in dogs

ObjectiveTo compare the duration of action of atracurium in diabetic and nondiabetic dogs. Study designProspective, blinded, clinical study. AnimalsA total of 26 diabetic and 29 nondiabetic dogs. MethodsFollowing preanaesthetic medication and intravenous (IV) propofol induction, anaesthesia was maintained with isoflurane in oxygen. Atracurium 0.2 mg kg−1 IV was administered to provide neuromuscular blockade (NMB) and the responses (twitches; T) to train-of-four nerve stimulation were recorded by palpation and electromyography (EMG). Time to onset of NMB (from atracurium administration to loss of T4 by EMG), duration of NMB (to return of T1 by EMG) and also times to loss and return of T2–T4 were recorded. Heart rate (HR), mean arterial pressure, end-tidal isoflurane (Fe′Iso), end-tidal CO2 concentrations and oesophageal temperature were recorded at onset of NMB and when T1EMG returned. Groups were compared using t tests and Mann–Whitney U tests (p<0.05). ResultsDiabetic dogs were older (9.9±0.3 compared with 6.8±0.7 years, p=0.0003). Group parameters were similar at onset and offset of NMB apart from HR at offset, which was higher for diabetics compared to nondiabetics (114±4 compared with 100±3 beats minute−1, respectively, p=0.004), Fe′Iso was higher in the diabetic group at onset (1.3±0.03% compared with 1.2±0.04%, p=0.026) and offset (1.4±0.03% compared with 1.3±0.03%, p=0.007), and temperature was higher for diabetics at onset (37.5±0.1 °C compared with 37.0±0.2 °C, p=0.012) and offset (37.5±0.1 °C compared with 36.9±0.2 °C, p=0.004). The duration of action of atracurium(tactile) and atracurium(EMG) were similar for both groups. Conclusions and clinical relevanceThe duration of action of atracurium was similar in diabetic and nondiabetic dogs as indicated by tactile and EMG monitoring.

Efficacy of clemastine fumarate in antagonizing atracurium-induced release of histamine in patients undergoing surgery under general anesthesia

Objective To evaluate the efficacy of clemastine fumarate in antagonizing atracurium-induced release of histamine in the patients undergoing surgery under general anesthesia. Methods Eighty American Society of Anesthesiologists physical statusⅠ or Ⅱ patients, aged 21-59 yr, with body mass index of 17-26 kg/m2, scheduled for elective modified radical mastectomy, were divided into 2 groups (n=40 each) using a random number table: control group (group C) and clemastine fumarat group (group CF). Clemastine fumarate 2 mg was injected intramuscularly at 20 min before induction of anesthesia.Anesthesia was induced with iv midazolam 0.1 mg/kg, etomidate 0.3 mg/kg, fentanyl 4-6μg/kg and atracurium 0.8 mg/kg.The patients were mechanically ventilated after insertion of the larygeal mask airway.Anesthesia was maintained with inhalation of 2% sevoflurane.Before administration of clemastine fumarate, at 20 min after administration, immediately before administration of atracurium, and at 2, 5, 10 and 20 min after administration of atracurium, arterial blood samples were taken for determination of plasma histamine concentrations, and the peak airway pressure and degree of cutaneous color were recorded.The development of histaminemia and adverse cardiovascular events was assessed.Steward recovery scores and Ramsay sedation scores were recorded at 10 min after removal of the laryngeal mask airway. Results The incidence of histaminemia was 60% and 8% in C and CF groups, respectively.Compared with group C, the plasma histamine concentrations, incidence of histaminemia, degree of cutaneous color, and incidence of hypotension and tachycardia were significantly decreased (P 0.05). Conclusion For atracurium-induced release of histamine in the patients undergoing surgery under general anesthesia, clemastine fumarate 2 mg injected intramuscularly before operation can not only antagonize histamine at H1 level, but also reduce histamine release, and exerts no influence on recovery from anesthesia and produces good antihistamine efficacy. Key words: Histamine H1 antagonists; Atracurium; Histamine release; Anesthesia, general

Frequency of occurrence of urticaria after the administration of atracurium

&lt;p class="abstract"&gt;&lt;strong&gt;Background:&lt;/strong&gt; Atracurium is a non-depolarizing neuromuscular blocking agent generally used for short and intermediate duration surgical procedures. Atracurium may cause urticaria due to direct, non-immunological release of histamine from mast cells.Though cutaneous changes due to histamine release by atracurium have been reported in various studies these changes were not clinically evaluated by dermatologists. The aim of the study was to assess the frequency of occurrence of urticaria after the administration of atracurium in the conventional dose schedule. Haemodynamic changes in pulse rate and mean arterial pressure (MAP) were also evaluated.&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Methods:&lt;/strong&gt; 60 patients aged 12 years and above, undergoing various elective surgical procedures were enrolled in the study. Atracurium was administered in a dose of 0.6 mg/kg body weight after induction. Cutaneous changes if any including erythema and urticarial weals were observed during the intraoperative phase and images recorded for further evaluation by the investigators including dermatologists. Baseline values of pulse rate and MAP as well as values 1 min, 3 min and 5 min after the administration of atracurium were recorded.&lt;strong&gt;&lt;/strong&gt;&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Results:&lt;/strong&gt; None of the patients developed urticarial weals after the administration of atracurium. Five patients (8.33%) developed erythema during the intraoperative period. Changes in pulse rate and MAP were found to be significant.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Conclusions:&lt;/strong&gt; Atracurium in conventional dosage is not associated with urticaria. Haemodynamic changes after the administration of atracurium are significant. &lt;/p&gt;

Recommendations and Low-Technology Safety Solutions Following Neuromuscular Blocking Agent Incidents

Neuromuscular blocking agents (NMBs) are high-risk medications used to facilitate endotracheal intubation and artificial ventilation. In an incident at a metropolitan tertiary referral and teaching public hospital in Australia, a neurosurgical patient became unresponsive at the start of surgery. It was determined that cisatracurium was administered in error in place of midazolam; the patient was ventilated and the emergency surgery continued. Two additional non-operating room (OR) drug-swap cases involving cisatracurium were reported within 12 months of this event, resulting in a comprehensive review of NMB safety. A root cause analysis (RCA) resulted in multiple interventions to decrease the risk of selection and administration errors: (1) review of NMB packaging and introduction of in-house NMB labeling by pharmacy procurement staff before distribution; (2) implementation of a medication administration in anesthetics guideline with ongoing education; (3) audit of storage with removal of NMBs; (4) review of new products by medication safety pharmacists and a senior anesthetist before distribution; and (5) use of red-barrel syringes for administering NMBs was expanded to all areas using NMBs to minimize syringe-swap incidents. In the four years since full implementation of interventions, there have been no reports of cisatracurum selection errors. An incident of atracurium administration resulted in further recommendations for review of OR cart storage. Ongoing monitoring via medication safety walkrounds, by OR staff, by the perioperative pharmacist, and through the hospital's medication incident monitoring system has not detected any further NMB incidents. Technological solutions have been shown to decrease the risk of NMB errors, yet multifaceted low-technology solutions may be an effective, cheaper alternative.

Influence of atracurium on selected cardiovascular and respiratory variables and surgical times in dogs undergoing laparoscopic ovariectomy with standardized ventilation pattern

Respiratory and cardiovascular changes in normocapnic dogs undergoing laparoscopic ovariectomy are described in this report. To-date, changes during a standardised ventilation pattern, irrespective of end-tidal CO2 (EtCO2) levels, have not been reported. This study was undertaken to describe these changes. Forty bitches undergoing laparoscopic ovariectomy were enrolled in a prospective double-blind randomised clinical trial. They were first anaesthetised with medetomidine-butorphanol-propofol and then maintained with isoflurane in oxygen-air. Ventilation pattern was pressure-controlled, volume-limited. After stabilisation, atracurium 0.4 mg/kg (ATR group, n = 20) or saline 0.04 ml/kg (SAL group, n = 20) was administered intravenously. Capnoperitoneum was then established with an intra-abdominal pressure setting of 10 mmHg. Collected data included heart rate (HR), non-invasive blood pressure, EtCO2, oxygen saturation of haemoglobin, and tidal volume and neuromuscular blockade (train-of-four). Data were recorded before administration of atracurium or saline, and at 2, 5, and 10 min thereafter. Subsequently, insufflation of CO2 was commenced. After capnoperitoneum was established, data were recorded at 2, 5 and 10 min. Time of capnoperitoneum induction and duration, time of ovary searching and excision and total time of capnoperitoneum and surgery were also recorded. For statistical analysis, the Shapiro Wilk test, ANOVA with repeated measures and Student's t-test for independent samples were used (P < 0.05). Significant increases in EtCO2 were observed in patients 5 min after atracurium administration and 5 min after capnoperitoneum was established in the ATR group, when compared to the SAL group. No other differences were found. Administration of atracurium in dogs undergoing laparoscopic ovariectomy with a standardised ventilation pattern did not result in clinically important differences in selected cardiovascular and respiratory variables and surgical times in comparison with non-relaxed dogs. Thus, the use of atracurium in laparoscopic ovariectomy does not result in any benefit for patients or surgeons.

Predictive value of allergy tests for neuromuscular blocking agents: tackling an unmet need.

Neuromuscular blocking agents (NMBAs) are a predominant cause of perioperative anaphylaxis in Europe. Diagnosis of NMBA allergy relies upon the careful review of the anaesthetic report complemented with skin tests. Additional diagnostic tests are quantification of specific IgE antibodies (sIgE) and basophil activation test (BAT). However, data on the predictive value of the skin tests, the BAT and the sIgE assays (drug-specific and substituted ammonium structures) are limited or not available, mainly because such exploration requires dangerous NMBA provocation tests. In this study, the predictive value of skin test, BAT and measurement of sIgE to substituted ammonium structures is gathered from a review of anaesthetic records of subsequent surgical procedures with NMBA administration and/or occurrence of perioperative incidents. We investigated a series of 272 patients with perioperative anaphylaxis, of whom 100 had undergone second general anaesthesia. Negative skin test and negative BAT assisted the selection of alternative NMBA, which were well tolerated in all cases. Five patients with a positive sIgE to rocuronium but with negative skin testing and BAT safely received rocuronium during second anaesthesia. Twelve patients with sIgE reactivity to morphine, but negative skin test and BAT to benzylisoquinolines, tolerated administration of cisatracurium or atracurium. Alternatively, benzylisoquinoline allergy went undetected in the morphine solid-phase assay. Skin test and BAT have an excellent negative predictive value in our series. The uneventful re-exposure of rocuronium in patients with an isolated positive sIgE result to rocuronium calls into question the predictive value of this assay and suggests sIgE serology to be less clinically predictive than the functional investigations relying upon activation of mast cells or basophils. The presence of a positive sIgE to substituted ammonium structures such as morphine does not preclude further use of benzylisoquinolines.

Evaluation of intubation condition following administration of rocuronium in comparison to atracurium in paediatric patients

Background. Optimum intubation condition is paramount important for early and easy passage of endotracheal tube through the glottis and that results from adequate muscle relaxation. Rocuronium and atracurium are muscle relaxants used for short and intermediate duration of surgical processes. Objective: This study, compares the intubation condition and haemodynamic changes in paediatric patients following administration of rocuronium and atracurium to get rid of the side effects of succinylcholine. Method. The study was carried out in 60 patients aged 11/2 to 10 years, ASA I-II, under general anaesthesia. The patients were divided into two groups: rocuronium Gr R and atracurium Gr A. Induction was done with halothane 3.5-4% and for intubation rocuronium 0.6 mg/kg and atracurium 0.46 mg/kg were given to patients of Gr R and Gr A respectively. The intubation condition was assessed and gradded at 60 seconds after neuromuscular blocking agents. At the same time TOF ratios were recorded. Results. Rocuronium produced good to excellent intubation condition (score 3.80 ± 0.07) in all patients at 60 seconds whereas that of atracurium poor intubation condition (score 2 ± 0.00). TOF ratios showed more relaxation of adductor pollicis muscle in Gr R than Gr A (Gr R = 60.43 ± 0.87, Gr A = 78.90 ± 0.72). (p &lt; 0.001). Cardiovascular stability was not significantly difference in both the groups before induction and intubation. Conclusion. Rocuronium produced better intubation condition in comparison to atracurium. DOI: http://dx.doi.org/10.3329/jbsa.v23i1.18150 Journal of BSA, 2010; 23(1): 3-7

Improving cost-efficiency at a hospital by showing the time-saving effect of using different neuromuscular blockers for short operations

Objectives Muscle relaxants are used in anaesthesia to obtain adequate muscle relaxation for intubation and operations. A goal of hospital management is to improve the hospital's budget by selecting adequate neuromuscular blocking agents for short-term operations. Methods A basic investigation was conducted of the time required to reach maximal blocking (MB) with administration of atracurium and rocuronium during anaesthesia induction and recovery time (RT). Patients were divided into random groups. Group R received rocuronium 0.6 mg/kg IV and group A received atracurium 0.5 mg/kg IV. Time required to reach MB and RT was measured with a train-of-four (TOF) device where MB and RT were named TOF0 and TOF75 respectively. Direct expenses were used to evaluate the effect on hospital budget. Key findings Mean times calculated to reach TOF75 in recovery with rocuronium and atracurium were 38 and 51 min respectively. Mean durations of operations where atracurium and rocuronium were used were 47 and 46 min respectively. In group R, patients reached TOF75 before the operation time and eventually extubated safely. In group A, the time to reach TOF75 was 51 min but operation time was 46 min and patients needed an additional 5 min for recovery and safe extubation. Preparation period was determined as 14 min. These results indicate that 60 min in group R and 65 min in group A were needed from the start of one operation to the start of the next. Conclusions This study showed that if a hospital's usage ratio is 100% performance capacity, and there are no other problems, in 1 month by using rocuronium it could perform an extra 15 paediatric surgical operations gaining additional income of US$2436 for one operation room per month.

Comparison of Two Different Induction Doses of Atracurium in Myasthenia Gravis in Patients Undergoing Thymectomy

Introduction:yasthenia gravis is an autoimmune disorder resulting from a decreased number of active acetylcholine receptors at the neuromuscular junction. Thymectomy is one of its current treatments. Due to sensitivity of myasthenic patients to non-depolarizing muscle relaxants and also the interaction of this medication with anti-cholinestrase drugs, determining the dosage of non-depolarizing muscle relaxants for induction of anesthesia is one of the hurdles in thymectomy. Materials and Methods :20 myasthenic patients undergoing transsternal thymectomy were enrolled into the study.They were divided into two groups randomly, and received either 0.25 mg/kg or 0.50 mg/kg of atracurium to facilitate tracheal intubation. Neuromuscular blockade was measured using train of four (TOF) mode of neuromuscular stimulator 15 minutes after administration of atracurium and then each 5 minutes till entered the recovery phase. The time between injection of atracurium and the recovery phase was compared between the two groups. Results:The two groups were similar with respect to age and gender. The time from the onset of myasthenia gravis to surgery, dosage and duration of pyridostegmine used preoperatively were not significantly different between the two groups.The time from administration of atracurium to recovery phase was not significant between the two groups (P=0.24). Conclusion:There was no difference between two different doses of atracurium regarding entering the recovery phase, and as the effects of non-depolarizing muscle relaxants are unpredictable in myasthenic patients, we recommend the lower dose to prevent profound skeletal muscle weakness and postoperative complications

The effects of atracurium on bispectral index (BIS) values in dogs anaesthetized with isoflurane

Balanced anaesthesia techniques employ specific drugs in addition to general anaesthetics. The potential effect of some of these drugs on the bispectral index (BIS) remains unclear. BIS seems to be unaffected by the administration of neuromuscular blockers while opioids may block nociceptive-induced BIS increases in anaesthetized humans. In this study, the effect of a single dose of atracurium on BIS values was assessed in dogs premedicated with morphine and anaesthetized with isoflurane (1 MAC). Fifteen female dogs undergoing elective ovariohysterectomy were employed. BIS values were recorded before and after the administration of atracurium. These values were then recorded again once the animals were surgically stimulated. The end tidal isoflurane concentration, cardiovascular and respiratory parameters were recorded through the study. Results show that the mean (±SD) BIS values decreased slightly, but significantly (P=0.033) from 67±8.42 to 65±5.84 after the administration of atracurium. Despite significant increase in heart rate and arterial pressure during the surgical phase, the mean BIS values were not modified by ovariohysterectomy. Atracurium appeared to have minimal clinical effect on the BIS in anaesthetized dogs.

Twitch potentiation: a potential source of error during neuromuscular monitoring with acceleromyography in anesthetized dogs

ObjectiveTo measure twitch potentiation (the staircase phenomenon) in anesthetized dogs, and assess its relevance during neuromuscular monitoring with acceleromyography (AMG). Study designRandomized, prospective clinical trial. AnimalsSixteen dogs undergoing ovariohysterectomy. MethodsUnder isoflurane anesthesia, neuromuscular function was monitored with train-of-four (TOF) stimuli every 15 seconds and quantified by AMG. Neuromuscular blockade (NMB) was produced with 0.15 mg kg−1 atracurium IV. Dogs were randomly divided into two groups; a potentiation group (PG) in which TOF stimulation was applied for 20 minutes before atracurium was administered; and a control group (CG) where no such time was allowed. In both groups, the AMG was calibrated (at tCAL) just before atracurium was administered. TOF stimulation continued throughout the experiment in all dogs. The height of the first twitch (T1) (expressed as a fraction of T1 at tCAL) and train-of-four ratio (TOFR) were recorded until TOFR returned to ≥90%. ResultsIn PG, T1 increased significantly (p = 0.0078) from a median of 102% (range, 95, 109) at baseline to 118% (100, 142) at 20 minutes. In PG, no difference was found between T1 at tCAL (immediately before atracurium administration) and T1 when neuromuscular transmission returned (p = 0.42). In the CG, T1 increased significantly between tCAL and the time neuromuscular transmission returned (p = 0.027). TOFR did not increase during twitch potentiation (all p = 0.32). Conclusions and clinical relevanceT1 increased significantly during 20 minutes of uninterrupted TOF stimulation in the absence of NMB, establishing that twitch potentiation occurs in anesthetized dogs. With no time for potentiation, T1 increased during the course of recovery from NMB; this phenomenon introduces a bias in T1 measurements and could affect studies reporting potency and duration of NMB based on T1 or single twitches. TOFR was unaltered by potentiation emphasizing its clinical usefulness for excluding post-operative residual NMB.

The effect of circadian rhythm on the duration of neuromuscular blockade produced by atracurium

Objective To investigate the effect of circadian rhythm on the duration of neuromuscular blockade (NMB) elicited by atracurium. Methods Sixty-one ASA Ⅰ or Ⅱ patients aged 18-55 yr with body mass index of 18-24 kg/m2 undergoing general anesthesia were enrolled in this study. Anesthesia was induced with fentanyl 2 μg/kg and propofol 2 mg/kg. Atracurium 0.75 mg/kg was injected iv as soon as the patients lost consciousness . NMB was assessed by TOF-stimulation of ulnar nerve using TOF-Watch(R) SX. Tracheal intubation was performed as soon as the first twitch (T1) disappeared. The patients were mechanically ventilation (VT 6-8 ml/kg, RR 12 bpm, I ∶ E 1.0 ∶1.5). PETCO2 was maintained at 35-45 mm Hg. Anesthesia was maintained with continuous infusion of propofol 6-8 mg·kg-1·-1·-1and remifentanil 0.25-0.50 μg·kg-1·min-1 . Anesthesia was performed at 5 time periods: (1) 8:00-11:00, (2) 11:00-14:00, (3) 14:00-17:00, (4) 17:00-20:00 and (5) 20:00-23:00. The duration of NMB produced by atracurium was defined as the interval between the end of atracurium injection and 3% recovery of T2 . The data were analysed using generalised linear models (GLMs) and cosinor method. Results Fifty-three cases completed the study. GLM analysis showed that the duration of NMB was longest at 20:00-23:00 (53 min (95% confidence interval 50-56 min)) and shortest at 11:00-14:00 (43 min (95% confidence interval 39-46 min)), suggesting that there is a significant diurnal variation in the duration of NMB elicited by atracurium. Cosinor method analysis showed that equation of the duration of NMB and time point of atracurium administration was y = 48.05 + 15cos( 15t + 52.66). Conclusion Circadian rhythm can affect the duration of NMB elicited by atracurium, which shows that the duration of NMB is longest at 20:00-23:00 and shortest at 11:00-14:00. Key words: Circadian rhythm; Atracurium; Neuromuscular blockade