BACKGROUND: The concept of the effect-site concentration of anesthetic agents is important. The effect compartment model can be explained using the concepts of effect-site concentration and effect-site equilibration rate constant (k e0). This study confirms that the time-to-peak effect (tpe ) can be measured easily in clinical practice by applying a priming dose and train-of-four (TOF) during general anesthesia induction, and k e0 can be calculated from the tpe of the four muscle relaxants that are commonly used in general anesthesia. METHODS: Eighty patients who received general anesthesia were divided into the succinylcholine, rocuronium, atracurium, or vecuronium groups. Priming doses of muscle relaxants were administered. The effects of muscle relaxants were quantified by recording the twitch response of the adductor pollicis muscle after stimulating the ulnar nerve. The tpe was measured at the lowest TOF value. k e0 was calculated from the measured tpe . RESULTS: The k e0 values of the succinylcholine, rocuronium, atracurium, and vecuronium groups were 0.076 (0.030)/min, 0.228 (0.122)/min, 0.062 (0.011)/min, and 0.077 (0.019)/min, respectively. CONCLUSIONS: It is possible to estimate k e0 from the tpe of muscle relaxants using a priming dose and TOF during general anesthesia induction.
Anesthesia, General* ; Anesthetics ; Atracurium ; Humans ; Succinylcholine ; Ulnar Nerve ; Vecuronium Bromide

OBJECTIVETo compare the pharmacokinetics of cisatracurium between normal weight patients and morbidly obese patients.

METHODSTwelve obese ASA I-II patients (BMI≥35 kg/m) undergoing laparoscopic Roux-en-Y gastric bypass and 12 normal weight ASA I-II patients (BMI of 18.5-24 kg/m) undergoing laparoscopic surgery were enrolled. The obese patients were given a cisatracurium dose of 0.15 mg/kg according to the fat-free mass (FFM), and the non-obese patients received a dose of 0.15 mg/kg according to the total body weight. Plasma concentrations of cisatracurium was monitored in the patients with high-performance liquid chromatography (HPLC) before anesthetic induction and at 1, 2, 4, 6, 8, 10, 12, 15, and 20 min after cisatracurium administration and the pharmacokinetic parameters were computed. SBP, DBP, HR, MAP, SpOand PetCOwere recorded before anesthetic induction (T) and at 1 min (T), 2 min (T), 4 min (T) after cisatracurium administration.

RESULTSCompared with those measured at T, SBP, DBP and MAP in the 2 groups were significantly decreased at the time points of T(P<0.05). Compared with the non-obese patients, the obese patients showed significantly increased Hct level (P<0.05). The total clearance, apparent volume of distribution, and distribution and elimination half-life of the drug were similar between the 2 groups (P>0.05). The plasma concentration of cisatracurium at Twas significantly decreased in the obese patients compared with that in the non-obese patients (P<0.05).

CONCLUSIONCisatracurium doses according to fat-free mass is clinically reasonable for inducing anesthesia in morbidly obese patients, but due to a prolonged muscle relax onset time, the timing of tracheal intubation should be delayed by 1-2 min.

Anesthesia ; Atracurium ; analogs & derivatives ; pharmacokinetics ; Gastric Bypass ; Half-Life ; Humans ; Laparoscopy ; Obesity, Morbid ; blood ; Time Factors

BACKGROUND: Although cisatracurium has many advantages in anesthetic practices, the best choice of a nondepolarizing neuromuscular blocking agent that can replace succinylcholine is rocuronium. However, it is reported that remifentanil with propofol might provide reliable intubating condition, even without a neuromuscular blocking agent; therefore, it might improve the intubating condition with cisatracurium. This study examined intubating conditions after administering rocuronium or cisatracurium in a rapid sequence induction with remifentanil-propofol. METHODS: Fifty two ASA physical status 1 or 2 adult patients scheduled for an elective surgery were enrolled in a randomized double-blinded trial. Anesthesia was induced in all patients with propofol 2.0 mg/kg and remifentanil 0.5 microgram/kg, administered over 60 seconds. Rocuronium 0.9 mg/kg (3 x ED95, R group, n = 23) or cisatracurium 0.15 mg/kg (3 x ED95, C group, n = 29) was administered after the induction sequence. Laryngoscopy was attempted when the anesthesiologist thought it was 90 seconds after drug administration and appropriate time for intubation. The examiner, another anesthesiologist, recorded the exact time to intubation and suppression of maximal T1 on TOF. The intubating condition was assessed by the first anesthesiologist, as excellent, good, poor or not possible. RESULTS: The best time to laryngoscopy was predicted by measuring TOF and was found to be significantly longer in the C group (197 +/- 53 s) than in the R group (102 +/- 49 s) (P value < 0.05). However, time to larygoscopy, intubating condition during the laryngoscopy, and hemodynamic changes after intubation was similar in both groups. CONCLUSIONS: Despite fundamentally slower onset time, cisatracurium can provide quite good intubating conditions, which were comparable to those achieved with equipotent doses of rocuronium, which is more expensive in anesthesia inducted with remifentanil and propofol.
Adult ; Androstanols ; Anesthesia ; Atracurium ; Hemodynamics ; Humans ; Intubation ; Laryngoscopy ; Neuromuscular Blockade ; Piperidines ; Propofol ; Succinylcholine

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.
Anesthesia ; Anesthesia, Intravenous ; Atracurium ; Female ; Humans ; Isaacs Syndrome ; Motor Neurons ; Muscle Cramp ; Muscle, Smooth ; Neuromuscular Blockade ; Neuromuscular Monitoring ; Piperidines ; Propofol ; Rotator Cuff ; Sweat ; Sweating

Cisatracurium was initially characterized to have no evident histamine-releasing potential with excellent cardiovascular stability. However, severe anaphylactic reactions to cisatracurium that resulted in bronchospasms and cardiovascular collapse have been reported worldwide. Two cases of severe anaphylactic reactions after the administration of cisatracurium are presented. The anesthetics used in both cases were lidocaine, midazolam, propofol (microemulsion propofol in the second case), remifentanil and cisatracurium. After the administration of these drugs, bronchospasm and hypotension manifested, leading to the diagnosis of anaphylaxis and appropriate treatment. Skin intradermal testing confirmed that both cases were due to immune-mediated anaphylaxis to cisatracurium, despite the fact that neither of the patients had been exposed to the allergen previously. The anaphylaxis may be due to cross-reactivity between neuromuscular blocking agents and substances with quaternary ammonium ions. Anesthesiologists should be aware that cisatracurium has the potential to trigger severe anaphylactic reactions via an immune-mediated mechanism.
Anaphylaxis ; Anesthesia, General ; Anesthetics ; Atracurium ; Bronchial Spasm ; Humans ; Hypotension ; Intradermal Tests ; Ions ; Lidocaine ; Midazolam ; Neuromuscular Blocking Agents ; Piperidines ; Propofol ; Quaternary Ammonium Compounds ; Skin

BACKGROUND: Dexmedetomidine is an alpha2-adrenoreceptor agonist with sedative, analgesic and anxiolytic effects, and it has more selective alpha2-adrenergic effect than clonidine. We evaluate the effect of preansethetic dexmedetomidine 1 microg/kg single infusion on sedation, hemodynamics, anesthetic consumption, and recovery profiles during anesthesia. METHODS: Forty-two female patients with American Society of Anesthesiologists physical status I or II undergoing gynecologic surgery with anticipated operation time of 2 h, were randomly assigned to receive dexmedetomidine 1 microg/kg (Dex group) or saline (control group) iv over 10 min before anesthetic induction. After tracheal intubation with propofol 2 mg/kg, cisatracurium 0.15 mg/kg iv, anesthesia was maintained with sevoflurane, O2 50%, N2O 50% around a BIS value of 40. RESULTS: After study drug infusion, BIS of Dex group was lower than that of control group (93.9 +/- 3.1 vs 51.5 +/- 5.2, P < 0.05). Mean arterial pressure (MAP) and heart rate (HR) after intubation were increased in control group, but did not change in Dex group. During maintenance, there was no difference in MAP between groups, but HR of Dex group was lower compared to that of control group. End-tidal concentration (2.0 +/- 0.5 vol% vs 1.4 +/- 0.3 vol%, P < 0.05) and total cumulative consumption of sevoflurane (34.6 +/- 3.8 ml vs 26.5 +/- 5.3 ml, P < 0.05) were lower in Dex group than in control group. Recovery profiles, modified Aldrete score, postoperative nausea vomiting, and visual analogue pain score were not significantly different between groups. CONCLUSIONS: Preanesthetic dexmetomidine 1 microg/kg single infusion is a simple, easy, and economic general anesthetic adjuvant that maintains stable hemodynamics and decrease anesthetic consumption without the change of recovery profiles.
Anesthesia ; Anesthesia, General ; Anti-Anxiety Agents ; Arterial Pressure ; Atracurium ; Clonidine ; Dexmedetomidine ; Female ; Gynecologic Surgical Procedures ; Heart Rate ; Hemodynamics ; Humans ; Intubation ; Methyl Ethers ; Postoperative Nausea and Vomiting ; Propofol ; Recovery of Function ; Vomiting

Vagal reflex during manipulation with a curved-blade laryngoscope and tracheal intubation may result in severe bradycardia and even, asystole. Manipulation with laryngoscope and tracheal intubation leaded to bradycardia and asystole at a 47-year-old woman during induction of anesthesia with propofol, remifentanil and cisatracurium and sevoflurane inhalation. Withdrawal of laryngoscope and atropine 0.5 mg injection, her heart rate was recovered to normal sinus rhythm. Intubation at secondary trial was done with bradycardia and heart rate was returned to normal sinus rhythm soon. She had a history of syncope in interview after surgery and was examined tilt test to find of cause of syncope. Although the result of the test was negative, the bradycardia and asystole seemed to be caused by vagal reflex.
Anesthesia ; Atracurium ; Atropine ; Bradycardia ; Female ; Heart Arrest ; Heart Rate ; Humans ; Inhalation ; Intubation ; Laryngoscopes ; Methyl Ethers ; Middle Aged ; Piperidines ; Propofol ; Reflex ; Syncope

BACKGROUND: Both ketamine and priming may accelerate the onset time of neuromuscular blocking agents. We investigate the effect of low dose ketamine and cisatracurium priming on the intubating condition and onset time of cisatracurium. METHODS: After Institutional Review Board approval, 120 consecutive patients undergoing general anesthesia were randomly assigned to one of 4 groups. All patients were injected one of normal saline (group C), cisatracurium 0.01 mg/kg (group P), ketamine 0.5 mg/kg (group K) and combination of cisatracurium 0.01 mg/kg, and ketamine 0.5 mg/kg (group PK) diluted into a 5 ml solution, followed 3 minutes later by cisatracurium 0.15 mg/kg in group C and K, and 0.14 mg/kg cisatracurium in priming group. Onset time was recorded the electromyographical responses using single twitch and intubating conditions were evaluated at 60 seconds after cisatracurium administration. RESULTS: The mean onset time was most significantly accelerated in Group PK and was also significantly more accelerated in Group P and K compared with Group C (P < 0.008). It was 112.7 +/- 13.2, 91.4 +/- 17.9, 84.9 +/- 12.7 and 76.4 +/- 8.3 seconds in Group C, P, K, and PK, respectively. Intubating conditions were significantly improved in Group P, K and PK than Group C (P < 0.008). Especially, Group PK showed most significant improvement of intubating conditions. CONCLUSIONS: The combination of the low dose ketamine and cisatracurium priming accelerated the onset time and was improved the intubating conditions.
Anesthesia, General ; Atracurium ; Ethics Committees, Research ; Humans ; Intubation ; Ketamine ; Neuromuscular Blocking Agents

BACKGROUND: To determine how pretreatment with magnesium sulfate (MgSO4) potentiates neuromuscular blocking agents. We investigated how the onset and recovery characteristics of cisatracurium are changed by pretreatment with MgSO4. METHODS: After Institutional Review Board approval, a total of 48 ASA I and II patients were devided into 2 groups. Patients in each group received either the MgSO4 30 mg/kg (group M) in 0.9% normal saline (total volume 100 ml) or 0.9% normal saline (control group C) alone intravenously for 15 min before induction of anesthesia with propofol, remifentanil and cisatracurium 0.15 mg/kg. Anesthesia was maintained with propofol and remifentanil. Electromyographical responses were measured by train-of-four. Lag time, onset time, total recovery time, clinical duration, recovery index, and recovery time were measured. The mean arterial blood pressure, heart rate, and ionized magnesium were also measured. RESULTS: The lag time and onset time were significantly shorter in the MgSO4 group than the control group (P < 0.05). Recovery index, recovery time, clinical duration, and total recovery time showed no significant differences in the MgSO4 group compared to the control group (P > 0.05). Mean arterial pressure was more significantly increased in the MgSO4 group than in the control group at the time point immediately after the administration of MgSO4. Heart rate showed no significant changes in both groups. The concentrations of ionized magnesium were significantly more increased at the all time point (P < 0.05). CONCLUSIONS: MgSO4 results in about 29% shortening of onset time of cisatracurium (0.15 mg/kg) without prolongation on the recovery of neuromuscular block.
Anesthesia ; Arterial Pressure ; Atracurium ; Ethics Committees, Research ; Heart Rate ; Humans ; Magnesium ; Magnesium Sulfate ; Neuromuscular Blockade ; Neuromuscular Blocking Agents ; Piperidines ; Propofol

BACKGROUND: To determine how pretreatment with magnesium sulfate (MgSO4) potentiates neuromuscular blocking agents. We investigated how the onset and recovery characteristics of cisatracurium are changed by pretreatment with MgSO4. METHODS: After Institutional Review Board approval, a total of 48 ASA I and II patients were devided into 2 groups. Patients in each group received either the MgSO4 30 mg/kg (group M) in 0.9% normal saline (total volume 100 ml) or 0.9% normal saline (control group C) alone intravenously for 15 min before induction of anesthesia with propofol, remifentanil and cisatracurium 0.15 mg/kg. Anesthesia was maintained with propofol and remifentanil. Electromyographical responses were measured by train-of-four. Lag time, onset time, total recovery time, clinical duration, recovery index, and recovery time were measured. The mean arterial blood pressure, heart rate, and ionized magnesium were also measured. RESULTS: The lag time and onset time were significantly shorter in the MgSO4 group than the control group (P < 0.05). Recovery index, recovery time, clinical duration, and total recovery time showed no significant differences in the MgSO4 group compared to the control group (P > 0.05). Mean arterial pressure was more significantly increased in the MgSO4 group than in the control group at the time point immediately after the administration of MgSO4. Heart rate showed no significant changes in both groups. The concentrations of ionized magnesium were significantly more increased at the all time point (P < 0.05). CONCLUSIONS: MgSO4 results in about 29% shortening of onset time of cisatracurium (0.15 mg/kg) without prolongation on the recovery of neuromuscular block.
Anesthesia ; Arterial Pressure ; Atracurium ; Ethics Committees, Research ; Heart Rate ; Humans ; Magnesium ; Magnesium Sulfate ; Neuromuscular Blockade ; Neuromuscular Blocking Agents ; Piperidines ; Propofol