Mitigating on-call symptoms through organizational justice and job control: a cross-sectional study among Finnish anesthesiologists.

BACKGROUND: On-call duty has been shown to be associated with health problems among physicians. However, it cannot be abolished, as patient safety has to be assured. Thus, we need to find factors that could mitigate the negative health effects of on-call duty. METHODS: The cross-sectional questionnaire of the buffering effects of organizational justice, job control, and social support on on-call stress symptoms was sent to all working Finnish anesthesiologists (n=550). RESULTS: The response rate was 60% (n=328, 53% men). High organizational justice, job control, and social support were associated with a low number of symptoms while on call or the day after in crude analysis and when adjusted for age, gender, and place of work. Only the association between justice and symptoms was robust to additional adjustments for on-call burden and self-rated health. In the interaction analysis among those being on call at the hospital, we found that the higher the levels of job control or organizational justice, the lower the number of symptoms. CONCLUSIONS: Job control and organizational justice successfully mitigated stress symptoms among those who had on-call hospital duties. It would be worth enhancing decision-making procedures, interpersonal treatment, and job control routines when aiming to prevent on-call stress and related symptoms.

Suicidality among Finnish anaesthesiologists.

BACKGROUND: Suicide rates among physicians have constantly been reported to be higher than in the general population and anaesthesiologists appear to lead the suicide statistics among physicians. METHODS: A cross-sectional questionnaire study was sent to all working Finnish anaesthesiologists (n=550) investigating their suicidality (ideation and/or planning and/or attempt). The response rate was 60%. RESULTS: One in four had at some time seriously been thinking about suicide. Respondents with poor health (crude odds ratios 11.2 and 95% confidence interval 3.8-33.0), low social support (10.5, 4.0-27.9), and family problems (6.5, 3.4-12.5) had the highest risk of suicidality. The highest risks at work were conflicts with co-workers (4.1, 2.3-7.1) and superiors (2.1, 1.2-3.6), on-call-related stress symptoms (3.9, 1.9-8.3) and low organizational justice (1.9, 1.1-3.2). If a respondent had several risk factors, the risk of suicidality doubled with each cumulating factor. CONCLUSIONS: The reported level of suicidal ideation among Finnish anaesthesiologists is worth concern. It should be of utmost importance to screen the risk factors and recognize suicidal physicians in order to help them. Interpersonal relationships, decision-making procedures, and on-call-burden should be focused on when aiming to prevent suicidality among physicians.

Attitudes to job turnover among Finnish anaesthetists.

BACKGROUND: Structural changes have led to higher workload and more frequent conflicts among hospital staff, which in turn has been shown to be associated with increased employee turnover. AIMS: To study the willingness of anaesthetists to change their employment and factors associated with it. Work-related, individual and family-related factors were investigated as potential influences on such willingness. METHOD: A postal questionnaire was sent to all working Finnish anaesthetists (N = 550). RESULTS: The response rate was 60%; 175 (53% of responders) were men. Of the respondents, 31% were willing to consider changing to another physician's job and 43% to a profession other than medicine. The most important correlates for these views were conflicts with superiors (odds ratio 6.1; 95% confidence interval 2.1-17.7) and co-workers (4.2; 1.4-12.2), low job control (2.6; 1.4-4.9), a sense of organizational injustice (2.4; 1.3-4.6), stress (6.5; 2.6-16.3) and job dissatisfaction (4.6; 2.4-8.8). CONCLUSIONS: The establishment of respect, trust and genuine dialogue between co-workers and superiors is needed to minimize the risk of loss of members of this occupational group.

We should work less at night.

There is growing amount of evidence that doctors' performance is poorer if they work for over-prolonged duties or at night. These working patterns decrease the standard of care and increase the health care expenses. Furthermore, night workers have serious health risks due to their non-physiological work shifts. Effective ways to reduce the overall consequences of fatigue and night work include minimising the amount of work carried out at nighttime and setting up rules for maximal hours for each work shift.

Stable plasma concentrations of unbound ropivacaine during postoperative epidural infusion for 24-72 hours in children.

BACKGROUND AND OBJECTIVES: The aim of this open, non-controlled, multi-centre study was to evaluate the pharmacokinetics and safety of a 24-72 h continuous epidural ropivacaine infusion in children aged 1-9 yr. METHODS: After induction of general anaesthesia, 29 ASA I-II children, scheduled for major surgery in dermatomes below T10 had lumbar epidural catheters placed. A bolus of ropivacaine, 2 mg kg(-1), was given over 4 min, followed immediately by an infusion of 2 mg mL(-1) ropivacaine 0.4 mg kg(-1) h(-1) for the next 24-72 h. RESULTS: Plasma concentrations of total ropivacaine (mean 0.83 and 1.06 mg L(-1) at 16-31 and 59-72 h, respectively) and alpha1-acid-glucoprotein (mean 13 and 25 micromol L(-1) at baseline and 59-72 h) increased over the course of the infusion. Plasma concentrations of unbound ropivacaine were stable throughout the epidural infusion (mean 0.021 range 0.011-0.068 and mean 0.016 range 0.009-0.023 mg L(-1) at 16-31 and 59-72 h, respectively) and were well below threshold levels associated with central nervous system toxicity in adults (0.35 mg L(-1)). Apparent unbound clearance (mean 346, range 86-555 mL min(-1) kg(-1)) showed no age-dependency. No signs of systemic toxicity or cardiovascular effects were observed. All patients received additional analgesics with morphine. CONCLUSION: Following a 24-72 h epidural infusion of ropivacaine 0.4 mg kg(-1) h(-1) in 1-9-yr-old children, the plasma concentrations of unbound ropivacaine were stable over time with no age-dependency.

Job satisfaction, work ability and life satisfaction among Finnish anaesthesiologists.

BACKGROUND: Organizational changes and relative growth of the ageing population together with related health problems seem to have increased stressfulness in the work of anaesthesiologists. However, little is known about their work-related well-being and the factors through which their situation could be improved. METHODS: A cross-sectional questionnaire study of the level and the determinants of job satisfaction, work ability and life satisfaction among female and male anaesthesiologists involved 258 Finnish anaesthesiologists working full time (53% men). RESULTS: The respondents had fairly high job satisfaction, work ability and life satisfaction. No gender differences appeared in these well-being indicators, but their determinants differed by gender. Job satisfaction was only associated with work-related factors in both genders: with job control in women and with job control and organizational justice in men. Work ability correlated with job control and health in both genders and with family life in women. Life satisfaction correlated with individual- and family related factors such as social support and family problems in both genders. Life satisfaction correlated with physical workload in men and health in women. Women had less job control, fewer permanent job contracts and more domestic workload than men. CONCLUSIONS: Job control and organizational justice were the most important determinants in work-related well-being. Work-related factors were slightly more important correlates of well-being in males, and family life seems to play a larger role in the well-being of female anaesthesiologists. Organizational and gender issues need to be addressed in order to maintain a high level of well-being among anaesthesiologists.

Oral naproxen but not oral paracetamol reduces the need for rescue analgesic after adenoidectomy in children.

BACKGROUND: Our aim was to show the efficacy of naproxen and paracetamol with and without pethidine on pain and nausea and vomiting after adenoidectomy. The primary outcome was the requirement of rescue analgesic for post-operative pain and the secondary outcome was post-operative nausea and vomiting (PONV). METHODS: A randomized, double-blind, placebo-controlled study design was used. Thirty minutes before anaesthesia induction, patients (n= 180) received either a single oral dose analgesic (naproxen 10 mg/kg or paracetamol 20 mg/kg) or a placebo. Half of the children received pethidine 1 mg/kg intravenously (i.v.) at the induction of anaesthesia. Post-operative pain was evaluated using an objective behavioural pain scale (OPS 0-9) and rescue medication, i.v. fentanyl 1 mug/kg, was administered if the child suffered from moderate or severe pain (OPS > or = 4). RESULTS: When pethidine was not used, 83% of the children in the naproxen group vs. 97% in the other two groups required rescue fentanyl (P < 0.05). The use of pethidine reduced the incidence of fentanyl requirement by 30% and the number of fentanyl doses by 50% (P < 0.001). It also equalized the effects of naproxen, paracetamol and the placebo making the pain model invalid for this kind of study. The drawback associated with better analgesia was a doubling of the incidence of PONV (P < 0.001). CONCLUSIONS: Oral naproxen (10 mg/kg), but not oral paracetamol (20 mg/kg), reduces the need for rescue analgesic after adenoidectomy in children. The sensitivity of the pain model is crucial for these types of studies.

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.

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.

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.

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.

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.

Advantages of fentanyl over morphine in analgesia for ventilated newborn infants after birth: A randomized trial.

OBJECTIVE: To compare the efficacy and adverse effects of fentanyl or morphine analgesia during the first 2 days of life in newborn infants who underwent mechanical ventilation. STUDY DESIGN: In a randomized double-blind trial, 163 infants were allocated to receive a continuous infusion of fentanyl (10.5 microg/kg over a 1-hour period followed by 1.5 microg/kg/hr) or morphine (140 microg/kg over a 1-hour period followed by 20 microg/kg/hr) for at least 24 hours. The severity of pain was assessed with physiological parameters, a behavioral pain scale, and stress hormone concentrations before and 2 and 24 hours after the start of treatment. RESULTS: The analgesic effect was similar in both groups, as judged by the pain scale. Plasma adrenaline and noradrenaline concentrations decreased significantly from 0 to 24 hours in both groups. Median adrenaline decrease was 0.5 nmol/L (interquartile range [IQR] 1.1;0.0) in the fentanyl and 0.7 nmol/L (IQR 1.3;0.1) in the morphine group, noradrenaline 2.1 nmol/L (IQR 9.0;0.2), and 3.0 nmol/L (IQR 7. 5;0.3), respectively. beta-endorphin decreased significantly only in the fentanyl group ( 14 pmol/L (IQR 28; 7), P <.05). Decreased gastrointestinal motility was less frequent in the fentanyl group (23% vs 47%, P <.01). CONCLUSIONS: With at least as effective analgesia as with morphine, fentanyl had fewer side effects. Fentanyl may be superior to morphine for short-term postnatal analgesia in newborn infants.

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.

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.

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.

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.

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.

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.