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Biomedical subjects

O A Meretoja

Publications and source records attributed to O A Meretoja.

At least 19 recordsLinked to original sources

On-call stress among Finnish anaesthetists.

We investigated on-call stress and its consequences among anaesthetists. A questionnaire was sent to all working Finnish anaesthetists (n = 550), with a response rate of 60%. Four categories of on-call workload and a sum variable of stress symptoms were formed. The anaesthetists had the greatest on-call workload among Finnish physicians. In our sample, 68% felt stressed during the study. The most important causes of stress were work and combining work with family. The study showed a positive correlation between stress symptoms and on-call workload (p = 0.009). Moderate burnout was present in 18%vs 45% (p = 0.008) and exhaustion in 32% and 68% (p = 0.015), in the lowest vs highest workload category, respectively. The symptoms were significantly associated with stress, gender, perceived sleep deprivation, suicidal tendencies and sick leave. Being frequently on call correlates with severe stress symptoms and these symptoms are associated with sick leave.

Adult↗

Allocation of tasks between anesthesiologists and anesthesia nurses in Finland.

BACKGROUND: The shortage of anesthesiologists in Finland is worsening. A survey was carried out in 2003 among head anesthesiologists and head nurses to clarify current practice and the potentials for reorganizing tasks between anesthesiologists and anesthesia nurses. A national working group analyzed the results. METHODS: A questionnaire concerning doctor and nurse resources in anesthesiology, current allocation of tasks, and opinions on how these tasks could be reallocated was sent to 87 head anesthesiologists and 32 head nurses in 45 different hospitals. The answers from the doctors and nurses were compared. RESULTS: The response rate of doctors and nurses was 87% and 100%, respectively. In the enrolled hospitals there were 64 unoccupied positions for specialists in anesthesiology. The ratio of anesthesiologists to operation rooms (OR) they attended varied between 0.3 and 1.5. Doctors and nurses reported the allocation of tasks quite similarly. The great majority of respondents considered spinal, epidural, and interscalene brachial plexus blocks, and the induction of general anesthesia to be tasks that should be performed by an anesthesiologist. Very few respondents of either profession were willing to reallocate tasks so that nurses could deliver general anesthesia, including endotracheal intubation, even in low-risk patients. CONCLUSION: Nurses could be trained nationwide to perform procedures already performed by locally trained nurses in some hospitals. To cope with the shortage of anesthesiologists, other strategies must be adopted in addition to transferring part of their work load to nurses.

Anesthesia, General↗

The safety and efficacy of cisatracurium 0.15 mg.kg(-1) during nitrous oxide-opioid anaesthesia in infants and children.

We studied the neuromuscular and cardiovascular effects of a single, rapidly administered intravenous dose of cisatracurium 0.15 mg.kg(-1) in 27 infants (aged 1-23 months) and 24 children (aged 2-12.5 years). After midazolam premedication, anaesthesia was induced and maintained with thiopental and alfentanil in addition to nitrous oxide in oxygen. Neuromuscular function was monitored by evoked adductor pollicis electromyography. At least 15 min after intubation, each patient received cisatracurium 0.15 mg.kg(-1) over 5 s. Complete neuromuscular blockade was produced by this dose in all but one infant. The mean (SD) onset time of maximal blockade was more rapid in infants [2.0 (0.8) min] than in children [3.0 (1.2) min], p = 0. 0011. The clinical duration of action of cisatracurium (recovery of evoked response to 25% of control) was significantly longer in infants [43.3 (6.2) min] than in children [36.0 (5.4) min], p < 0.0001. Once neuromuscular function started to recover, the rate of recovery was similar in both age groups. Changes in blood pressure and heart rate after the administration of cisatracurium were negligible in both age groups. Cisatracurium, at a dose of 0.15 mg. kg(-1), was effective and well tolerated in infants and children.

Anesthesia, General↗

A dose-ranging study of rapacuronium in pediatric patients.

BACKGROUND: The aim of this study was to determine the dose or doses of the new rapid-onset, short-acting, neuromuscular blocking drug rapacuronium that would provide satisfactory conditions for tracheal intubation at 60 s in infants and children. METHODS: Sixty-five infants (< 1 yr), 51 younger children (1-6 yr), and 49 older children (7-12 yr) were studied. Anesthesia was induced with thiopental-nitrous oxide-oxygen. Tracheal intubation was attempted 60 s after administration of one of five doses of rapacuronium (0.5, 1.0, 1.5, 2.0, or 2.5 mg/kg) and intubating conditions were assessed using a four-point scale. Following tracheal intubation, anesthesia was maintained with nitrous oxide-oxygen and alfentanil (12.5-50 microg/kg) as necessary. Neuromuscular transmission was monitored in an uncalibrated fashion using an acceleromyograph. RESULTS: Intubating conditions were good or excellent at 60 s in all infants after doses of 1.5 mg/kg or more and in all younger and older children after doses of 2.0 mg/kg or more. The duration of action of rapacuronium was dose- and age-dependent. Mean times to reappearance of the third twitch of the train-of-four (TOF; T3) were less than 10 min in infants at doses of 1.5 mg/kg or less and in younger and older children at doses of 2.0 mg/kg or less. Recovery of T3 after 1.0-2.0 mg/kg rapacuronium was significantly slower in infants compared with younger (P = 0.001) and older (P = 0.02) children. Five adverse experiences were related to rapacuronium administration: Bronchospasm (two instances), tachycardia (one instance), and increased salivation (two instances). None were serious. CONCLUSIONS: Doses of 1.5 and 2.0 mg/kg rapacuronium can produce satisfactory intubating conditions at 60 s in anesthetized infants and children, respectively, and are associated with a short duration of action.

Age Factors↗

Morphine-sparing effect of acetaminophen in pediatric day-case surgery.

BACKGROUND: Postoperative pain is a major problem in day-case surgery in children. Nonsteroidal antiinflammatory drugs have gained popularity in management of pediatric surgical patients to reduce the need for opioids. The aim of this study was to evaluate the efficacy of different doses of rectal acetaminophen in day-case surgery in children. METHODS: A randomized, double-blinded, placebo-controlled study design was used. Patients (n = 120) were randomized to receive a single dose of 0, 20, 40, or 60 mg/kg of rectal acetaminophen after induction of anesthesia. General anesthesia was induced by mask ventilation with sevoflurane (7%) in nitrous oxide and oxygen and maintained with 2.5-4.0% end-tidal sevoflurane. Opioids or local anesthetics were not used. Postoperative pain was evaluated by behavioral assessment and physiologic measurements every 10 min after arrival at the postanesthesia care unit. The pain intensity was scored using a 0-100 visual analog scale used in the authors' clinic. The need for rescue medication, intravenous morphine 0.1 mg/kg, was decided by the nurse, who was unaware of the rectal acetaminophen dose. The parents were interviewed by phone after 24 h regarding pain and its treatment, nausea, and vomiting. Rescue analgesia at home was rectal ibuprofen, 10 mg/kg. RESULTS: In the postanesthesia care unit pain scores were significantly lower in the 40- and 60-mg/kg groups compared with placebo and 20-mg/kg groups. Acetaminophen resulted in a dose-related reduction in the number of children who required postoperative rescue opioid, with significance reached with 40 or 60 mg/kg doses. Calculated dose of acetaminophen at which 50% of the children not requiring a rescue opioid was 35 mg/kg. The need for rescue analgesia at home during the first 24 h after surgery was also significantly less in patients in the 40- or 60-mg/kg groups than in the 0- or 20-mg/kg groups (20-17 vs. 80-63%). Thirty-three percent of patients receiving placebo had postoperative nausea and vomiting, compared with 0-3% in groups receiving 40 or 60 mg/kg acetaminophen. CONCLUSIONS: A single dose of 40 or 60 mg/kg of rectal acetaminophen has a clear morphine-sparing effect in day-case surgery in children if administered at the induction of anesthesia. Moreover, children with adequate analgesia with acetaminophen have less postoperative nausea and vomiting.

Acetaminophen↗

Age related variability in the effects of mivacurium in paediatric surgical patients.

PURPOSE: This study describes the effects of 0.3 mg.kg-1 mivacurium in 180 paediatric patients between the ages of one month and 13 yr. METHODS: Alternate patients at each of two geographic sites received nitrous oxide-halothane or nitrous oxide-opioid anaesthesia. Neuromuscular blockade was monitored by electromyography (Datex NMT). Blood pressure and heart rate were recorded from an automated oscillometer. Tracheal intubation was performed 90 sec after administration of mivacurium and conditions were judged by the Krieg scale. RESULTS: There was no difference in the time course of block between anaesthetics or geographic sites. The average time to 90% block and 25% recovery was 1.0 min and 8.0 min at one month vs 2.3 min and 9.8 min at 12.5 yr of age. Intubation conditions were better during opioid (excellent in 92%) than during halothane anaesthesia (excellent in 78%) (P = 0.03). Diaphragmatic movement was less frequent in younger patients (P < 0.001). Intubation conditions did not differ between the two geographic sites. In the first minute after mivacurium, systolic and diastolic blood pressures decreased (P < 0.001) to similar extents in all patients. A transient increase in the redness of the skin of the face, trunk, and/or arms was noted during both anaesthetics (28% of infants, and 61% of children over five yr of age). CONCLUSION: The time course of block produced by mivacurium is more rapid in younger paediatric patients. The time course of mivacurium does not have the transatlantic variation which has been observed for vecuronium. Physiological changes suggestive of histamine release were frequent. Intubation conditions were very likely to be acceptable 90 sec after 0.3 mg.kg-1 mivacurium.

Adolescent↗

Potency and hourly maintenance requirement of combinations of mivacurium and pancuronium in adults.

PURPOSE: To evaluate the dose-response and maintenance requirements of a combination of mivacurium and pancuronium (cMP) in clinical practice. METHODS: In a randomised, open clinical study, 70 patients, 17-50 yr of age, were anaesthetised with propofol, alfentanil and nitrous oxide in oxygen. Thirty patients received mivacurium and 20 patients received pancuronium to establish dose-response curves for these agents. Hourly maintenance requirements of mivacurium and pancuronium to maintain 90-95% neuromuscular blockade (NMB) were determined. Thereafter, 20 additional patients received cMP in incremental doses to establish a cumulative dose-response curve for cMP followed by maintenance doses of cMP. NMB was recorded by adductor pollicis electromyography. RESULTS: The ED95 values for mivacurium and pancuronium were 100 and 66 micrograms.kg-1, respectively; and for the cMP 2:1 (in mg:mg basis), 32 micrograms.kg-1 mivacurium together with 16 micrograms.kg-1 pancuronium. This cMP was 1.8 times more potent than one parent agent (P < 0.0001). When cMP 2:1 was used, 60% of normal maintenance requirement of pancuronium reduced the requirement of mivacurium by > 90%. If cMP 20:1 was used, then 20% of normal maintenance requirement of pancuronium reduced the requirement of mivacurium by > 70%. Neostigmine 35 micrograms.kg-1 given at T1 10% recovery following cMP reversed the NMB to a TOF ratio of 0.70 in 9.5 +/- 3.9 min. CONCLUSION: These results reflect considerable synergism between mivacurium and pancuronium. The cMP is near intermediate-acting and the NMB is easily reversed with neostigmine. By using cMP, it may be possible to save some pharmacological costs during maintenance of anaesthesia.

Adolescent↗

The pharmacodynamics of mivacurium preceded by atracurium or cisatracurium in children.

UNLABELLED: We evaluated whether mivacurium maintains its short duration of effect when preceded by atracurium or cisatracurium in 45 children during propofol/alfentanil/N2O/O2 anesthesia. Neuromuscular response was recorded by using an adductor pollicis electromyogram (EMG). Children were randomized to receive two doses of atracurium (350 micrograms/kg and 70 micrograms/kg in Group AM), cisatracurium (64 micrograms/kg and 10 micrograms/kg in Group CM), or mivacurium (200 micrograms/kg and 100 micrograms/kg in Group MM), followed by a final dose of mivacurium 100 micrograms/kg. The second and third doses of the muscle relaxants were administered at 25% EMG recovery. After the final dose of mivacurium, the times to 95% of EMG recovery in groups AM, CM, and MM were (median with 10-90 percentile range) 33.0 (28.0-40.0) min, 30.7 (26.0-40.3) min, and 10.3 (8.0-14.0) min, respectively (P < 0.0001). The recovery times to a train-of-four ratio of 0.70 were 30.3 (24.7-37.0) min, 28.0 (24.7-37.7) min, and 10.3 (8.0-13.7) min for groups AM, CM, and MM, respectively (P < 0.0001). Thus, the duration of effect of mivacurium was prolonged by 200% if preceded by either atracurium or cisatracurium. IMPLICATIONS: We compared the pharmacodynamics of mivacurium given alone or preceded by atracurium or cisatracurium in children. The duration of effects of mivacurium was prolonged by 200% if preceded by either atracurium or cisatracurium. This implies that mivacurium has a short duration of effect only when given as a single relaxant.

Adolescent↗

Pipecuronium revisited: dose-response and maintenance requirement in infants, children, and adults.

STUDY OBJECTIVE: To compare dose-response relationship and maintenance requirement of pipecuronium in anesthetized infants, children, and adults. DESIGN: Prospective, consecutive sample trial. SETTING: Operating room at a university hospital. PATIENTS: 15 infants (1-11 months), 15 children (3-10 years), and 15 adults (35-50 years) of ASA physical status I and II. INTERVENTIONS: Anesthesia was induced and maintained with N2O:O2 2:1 and 1 minimum alveolar concentration end-tidal halothane. The neuromuscular function was recorded by adductor pollicis electromyogram evoked by a train-of-four ulnar nerve stimulation at 20 second intervals. An individual cumulative log-probit dose-response curve was established and maintenance requirement of pipecuronium determined. Between-group comparisons were made by analysis of variance and Scheffe F-test. MEASUREMENTS AND MAIN RESULTS: Dose-response curves were parallel with a dose-requirement of pipecuronium similar in infants and adults (ED95 of 40-42 micrograms/kg) and greater in children (ED95 of 52 micrograms/kg). After 30 minutes of surgical neuromuscular block, pipecuronium was required in each age group at a rate of 0.6 to 0.7 individual ED95 doses per hour to maintain an 85% to 95% neuromuscular block. CONCLUSIONS: Bolus dose requirement of pipecuronium is greatest in children. Maintenance requirement is related to potency in each age group studied.

Adult↗

Orotracheal fibreoptic intubation in children under general anaesthesia.

Orotracheal fibreoptic intubation under general anaesthesia in children was studied in eleven consecutive patients of three months to eight-years-of-age without anticipated intubation difficulties. One case report is also included. Three fibrescopes with a different diameter were used in the study. The fibrescope used was chosen so that it fitted snugly in the tracheal tube. The fibreoscopy was prolonged in one patient due to mucus and two tries were needed. Resistance to the tracheal tube upon intubation was encountered in five patients, only one of these patients was older than two years. Fibreoptic intubation succeeded in nine patients. Two patients were intubated with the Macintosh laryngoscope. The problems encountered in children during orotracheal fibreoptic intubation under general anaesthesia are the same as with adults: easy fibreoscopy is not always followed by easy tracheal intubation, there may be prolonged fibreoscopy and failed intubations. Manipulation of the tracheal tube can lead to successful tracheal intubation and resistance to the tube is more common in smaller children.

Anesthesia, General↗

Pharmacokinetics and pharmacokinetic-dynamic modelling of rocuronium in infants and children.

We have determined the pharmacokinetics and pharmacokinetic-pharmacodynamic relationship of rocuronium in infants and children. We studied infants (n = 5, 0.1-0.8 yr) and children (n = 5, 2.3-8 yr), ASA II, in the ICU while undergoing artificial ventilation under i.v. anaesthesia with an arterial cannula in situ and the EMG of the adductor pollicis muscle was monitored. Rocuronium 0.06 (infants) and 0.09 (children) mg kg-1 min-1 was given i.v. over +/- 5 min until 85% neuromuscular block was obtained. Arterial blood samples were obtained over 240 min. Plasma concentrations were measured by HPLC. Pharmacokinetic-dynamic variables were calculated using the Sheiner model and the Hill equation. Statistical analysis was performed using the Mann-Whitney U test (P < 0.05). The mean administered dose was 0.32 (SD 0.08) mg kg-1 and 0.4 (0.1) mg kg-1 for infants and children, respectively. Infants differed from children in plasma clearance (4.2 (0.4) vs 6.7 (1.1) ml min-1 kg-1), distribution volume at steady state (231 (32) vs 165 (44) ml kg-1), mean residence time (56 (10) vs 26 (9) min), concentration in the effect compartment at 50% block (1.2 (0.4) vs 1.7 (0.4) mg litre-1) and the slope of the concentration-effect relationship (5.7 (1.3) vs 3.9 (0.5)). Calculated mean ED90 values were 0.26 and 0.34 mg kg-1 for infants and children, respectively. The time course of neuromuscular block after equipotent doses did not differ.

Aging↗

The influence of the duration of isoflurane anaesthesia on neuromuscular effects of mivacurium.

BACKGROUND: The pharmacodynamic profile of muscle relaxants is usually changed by volatile anaesthetics. These changes seem to be time-dependent, even though few data are available to substantiate this. METHODS: We studied neuromuscular effects of a single dose of mivacurium (0.2 mg.kg-1) during short and intermediate duration of isoflurane anaesthesia. Forty-five children 1-10 years of age were randomized to receive 1.5% end-tidal concentration of isoflurane in N2O/O2 for 10 or 30 min (groups Iso-10 and Iso-30, respectively) or to receive nitrous oxide in oxygen for 10 min (Group N2O) before 0.2 mg.kg-1 of mivacurium was given. Neuromuscular response was recorded by adductor pollicis electromyogram. RESULTS: The onset time of mivacurium was shorter in Group Iso-30, 1.7 (1.0-2.3) min than in Group Iso-10, 2.3 (1.7-3.3) min or Group N2O, 2.3 (1.7-3.3) min (median with 10-90% percentiles) (P < 0.05). In Group Iso-30 the recovery time of the first EMG response was significantly longer than in groups Iso-10 and N2O (P < 0.0001). Groups Iso-10 and N2O did not differ from each other. CONCLUSION: Our results indicate that the duration of a constant concentration of isoflurane anaesthesia influences significantly the pharmacodynamics of mivacurium. The duration of a volatile anaesthesia is critical when potentiation of NMB is evaluated or compared in neuromuscular studies.

Anesthesia↗

Can final EMG baseline be used as a reference to calculate neuromuscular recovery?

BACKGROUND: Investigations recording recovery times of muscle relaxants have used initial or final baseline of a neuromuscular trace, or both, as a reference for data analysis. We evaluated the use of final baseline of EMG traces as a reliable reference to calculate recovery times. METHODS: We analyzed EMG traces from 82 children who had full spontaneous neuromuscular recovery following a single dose of mivacurium. Times from administration of mivacurium to 25, 50, 75, and 90% EMG recoveries were measured using both initial and final baselines as a reference. EMG traces with final baseline of 100 +/- 10% of the initial baseline were regarded as optimal. Recovery times from all other traces were compared to the times obtained from these optimal traces. Poor final baseline was defined as that of < 80% of initial baseline. Inter-group comparisons were made using Kruskal-Wallis test followed by Mann-Whitney U tests. RESULTS: EMG recovery times were similar for optimal traces whether the reference was the initial or the final baseline of the EMG trace. If the final baseline was used as the reference, then traces with poor final EMG baseline also showed similar neuromuscular recovery times. If the initial baseline was used as the reference for EMG traces with poor final baseline, then neuromuscular recovery times became 24-55% longer (P < 0.05). CONCLUSIONS: We conclude that the final baseline of an EMG trace can be used as a reference for calculations of neuromuscular recovery times following a bolus injection of mivacurium.

Child↗

Potency of doxacurium in infants, children, and adolescents during N2O-O2-alfentanil anesthesia.

STUDY OBJECTIVE: To evaluate neuromuscular potency of doxacurium during balanced anesthesia in pediatric patients. DESIGN: Prospective, consecutive sample trial. SETTING: Operating room at a university hospital. PATIENTS: 15 infants (1 to 11 months), 20 children (3 to 10 years), and 20 adolescents (13 to 19 years). INTERVENTIONS: Anesthesia was induced and maintained with thiopental, alfentanil, and nitrous oxide in oxygen. No volatile drugs were used at any time during the study. The neuromuscular function was recorded as adductor pollicis electromyography evoked by a train-of-four stimulation at 20-second intervals. A cumulative log-dose probit-response curve of doxacurium was established for every patient. MEASUREMENTS AND MAIN RESULTS: ED50 and ED95 doses of doxacurium (14 micrograms/kg and 25 micrograms/kg in infants, 26 micrograms/kg and 53 micrograms/kg in children, and 20 micrograms/kg and 41 micrograms/kg in adolescents, respectively) were smallest in infants and greatest in children (p < 0.05 between each pair of groups by analysis of variance and Scheffe's F-test). CONCLUSIONS: Potency of doxacurium was greatest in infants and least in children. We suggest that doxacurium can be administered safely in infants, and with dosages close to those reported in adults. Children's dose requirement was almost 50% greater than that of infants.

Adolescent↗

Cisatracurium during halothane and balanced anaesthesia in children.

Cisatracurium, 51W89, is one of the ten stereoisomers of Tracrium which, unlike atracurium, has been reported to have a lack of histamine mediated cardiovascular effects at doses as high as 8 x ED95 in adults. We compared the time-course of neuromuscular effects of 80 micrograms.kg-1 or 100 micrograms.kg-1 cisatracurium during N2O-O2-halothane or N2O-O2-opioid anaesthesia, respectively, in 32 children 2-12 years old. Neuromuscular function was monitored by evoked adductor pollicis EMG. Even-numbered patients (n = 16) were allowed to obtain full spontaneous recovery of neuromuscular function and odd-numbered patients (n = 16) received neostigmine 45 micrograms.kg-1 together with glycopyrrolate at the time of 25% EMG recovery. Data are expressed as median with 10th to 90th percentile range. Cisatracurium had an onset time (time from administration to maximal effect) of 2.2 (1.7-3.8) or 2.3 (1.8-4.9) min, a clinical duration (time to 25% EMG recovery) of 34 (22-40) or 27 (24-33) min, and a spontaneous 25-75% recovery time (time from 25 to 75% EMG recovery) of 11 (9-13) or 11 (7-12) min during halothane or balanced anaesthesia, respectively (NS). Train-of-four ratio recovered to 0.70 in 2.5 (1.8-3.0) or 3.2 (2.1-4.3) min following neostigmine during halothane or balanced anaesthesia, respectively (NS). Changes in blood pressure or heart rate following cisatracurium were negligible. We regard cisatracurium as a safe and promising intermediate duration muscle relaxant the effects of which can easily be reversed with neostigmine.

Anesthesia↗

Time course of potentiation of mivacurium by halothane and isoflurane in children.

We studied 40 children, aged 1-15 yr, to analyse the time course of potentiation of mivacurium produced by halothane and isoflurane. A steady infusion requirement of mivacurium to maintain 90% neuromuscular block was established during thiopentone-alfentanil-nitrous oxide-oxygen anaesthesia. Patients were then allocated randomly to receive 1 MAC end-tidal concentration of either halothane (group Hal) or isoflurane (group Iso) while neuromuscular block was maintained at 90%. Both volatile agents decreased the infusion requirements of mivacurium in an exponential manner in that maximal potentiation occurred only after 30-80 min. Maximal reduction in infusion rate (32% in group Hal and 70% in group Iso; P < 0.0001) did not depend on the age of the child but became established sooner the younger the child in the case of isoflurane (P = 0.002).

Adolescent↗

Sevoflurane-nitrous oxide or halothane-nitrous oxide for paediatric bronchoscopy and gastroscopy.

We have studied 120 infants and children, in three age groups (3-11 months, 1-5 yr and 6-15 yr), to compare anaesthesia with sevoflurane or halothane for bronchoscopy or gastroscopy, or both. Premedication or i.v. anaesthetic agents were not used. Patients were allocated randomly to receive either 7% sevoflurane or 3% halothane in 66% nitrous oxide in oxygen for induction of anaesthesia. The same inspired mixture was continued during bronchoscopy while the concentration of the inhalation agent was reduced by 50% during gastroscopy. Induction times were shorter for infants than for children and shorter for sevoflurane than for halothane. Cardiac arrhythmias were significantly more frequent during halothane than during sevoflurane anaesthesia. Physiological and psychomotor recovery were more rapid after sevoflurane than after halothane. At 24-h follow-up, children who received sevoflurane had significantly less nausea and vomiting. We conclude that sevoflurane was superior to halothane for paediatric bronchoscopy and gastroscopy.

Adolescent↗

Mivacurium when preceded by pancuronium becomes a long-acting muscle relaxant.

BACKGROUND: To ensure rapid recovery of neuromuscular block, it might be useful to administer a short-acting relaxant after a long-acting one. Therefore, the interaction between pancuronium and mivacurium was investigated when mivacurium was administered during the recovery from pancuronium block. METHODS: After written informed consent, 41 adult patients were studied during propofol/alfentanil/nitrous oxide/oxygen anesthesia. Neuromuscular function was monitored using an electromyographic (EMG) method. AFter a stable EMG calibration response, cumulative doses of pancuronium were given to establish a 95% neuromuscular block. In the control group, and ED95 dose of 100 microg/kg mivacurium was administered instead of pancuronium. When the EMG response after pancuronium or mivacurium had recovered to 25% of the baseline, a single randomized intravenous bolus dose of 10 or 70 microg/kg mivacurium was given. Thereafter, spontaneous recovery of the neuromuscular function was recorded. RESULTS: The time from pancuronium until T1 25% EMG recovery was 38 +/- 12 min (mean +/- SD). The respective times after 10 or 70 microg/kg mivacurium were 28 +/- 8 and 54 +/- 7 min in the pancuronium group or 3 +/- 1 (n=3) and 10 +/- 4 min in the mivacurium group (P=0.0001). Times to 95% EMG recovery after 10 or 70 microgm/kg mivacurium were 77 +/- 14 and 97 +/- 16 min in the pancuronium group and 11 +/- 3 and 20 +/- 7 min in the mivacurium group, respectively (P<0.0001). Recovery indexes after 10 or 70 microg/kg mivacurium group, respectively (P<0.0001). Recovery indexes after 10 or 70 microg/kg mivacurium wre 26 +/- 4 and 22 +/- 6 min in the pancuronium group or 7 +/- 3 (n=3) and 5+/- 2 min in the mivacurium group, respectively (P<0.0001). Times from the administration of 10 or 70 microg/kg mivacurium until train-of-four ration 0.7 were 94 +/- 16 and 111 +/- 14 min in the pancuronium group and 12 +/- 4 and 22 +/- 8 min in the mivacurium group, respectively (P<0.0001). CONCLUSIONS: After pancuronium, mivacurium is not a short acting neuromusclar blocking agent.

Adult↗