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BACKGROUND: In the healthcare domain, different analytic tools focused on accidents appeared to be poorly adapted to sub-accidental issues. Improving local management and intra-institutional communication with simpler methods, allowing rapid and uncomplicated meta-reporting, could be an attractive alternative. METHODS: A process-centered structure derived from the industrial domain - DEPOSE(E) - was selected and modified for its use in the healthcare domain. The seven exclusive meta-categories defined - Patient, Equipment, Process, Actor, Supplies, work Room and Organization- constitute 7CARECAT™. A collection of 536 "improvement" reports from a tertiary hospital Post anesthesia care unit (PACU) was used and four meta-categorization rules edited prior to the analysis. Both the relevance of the metacategories and of the rules were tested to build a meta-reporting methodology. The distribution of these categories was analyzed with a χ 2 test. RESULTS: Five hundred and ninety independent facts were collected out of the 536 reports. The frequencies of the categories are: Organization 44%, Actor 37%, Patient 11%, Process 3%, work Room 3%, Equipment 1% and Supplies 1%, with a p-value <0.005 (χ 2). During the analysis, three more rules were edited. The reproducibility, tested randomly on 200 reports, showed a <2% error rate. CONCLUSION: This meta-reporting methodology, developed with the 7CARECAT™ structure and using a reduced number of operational rules, has successfully produced a stable and consistent classification of sub-accidental events voluntarily reported. This model represents a relevant tool to exchange meta-informations important for local and transversal communication in healthcare institutions. It could be used as a promising tool to improve quality and risk management.

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BACKGROUND: Neuromuscular blocking agents have always shown wide inter-individual variability when it comes to their duration of action. This prevents clinicians from anticipating the evolution of the neuromuscular block for any given patient. With this study, we aimed to assess the nature of the relationships existing between different time course parameters used to describe paralysis onset and offset. METHODS: Sixty American Society of Anesthesiologists (ASA) score III-IV anaesthetised patients were randomised to receive a single equipotent dose (2ED95) of either rocuronium, mivacurium or atracurium. We used acceleromyography to monitor neuromuscular transmission. We described the relationships between the time-interval measurements of: onset, the first response (T1) reappearance, T1 25% of control, train-of-four ratio 0.25 and 0.75. Pearson correlation coefficients were calculated. RESULTS: We found no significant relationships between onset and any of the four parameters used to describe the offset. On the other hand, we showed strong and highly significant linear relationships between all the parameters describing the offset for each of the muscle relaxants studied (correlation coefficients ranging from 0.850 to 0.992). CONCLUSIONS: We evidenced strong linear correlations between the four offset time course parameters of spontaneous recovery after a single neuromuscular blocking agents (NMBAs) bolus. Such relationships open up new clinical perspectives concerning quantitative neuromuscular transmission monitoring: the scope of individual valuable anticipation of the patient's recovery.

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OBJECTIVES: To report any item documenting the peroperative muscle relaxant effects management in anaesthesia files issued from visceral surgery processes. TYPE OF STUDY: Prospective, observational and multicenter. PATIENTS AND METHODS: A single operator analysed 1453 files proposed by nine anaesthetists' teams. The items selected concerned three periods: induction/tracheal intubation, paralysis maintenance, tracheal extubation. Reporting of 40 categories of items was studied. RESULTS: Items related to laryngoscopy and intubation conditions were observed in 43% (0-95) [general average (intercentres min-max)] and in 11% (0-97) of the files, respectively. At least one level of paralysis was reported in 23% (0-96) of the files. For the paralysis maintenance, documentation of an effect appeared in 53% (4-96) of the documents. Neuromuscular assessments preceding the tracheal extubation were retrieved in 43% (12-89) of the notes. Adductor pollicis was concerned for 30% (1-89) of these observations. Detection of level of spontaneous paralysis offset, satisfying to the local standard, appeared in 14% (3-19) of the documents. Pharmacological reversal was noted for 25% (4-67) of the patients; the assessment of the effects so produced was reported in 8% (0-58). CONCLUSION: In the studied collection, the traceability of the peranaesthetic curarization management appears variable on both qualitative and quantitative levels. The emergence of a dedicated guideline - defining the criteria for producing a good documentation of the muscle relaxant use - becomes necessary to secure these practices for all physicians using muscle relaxants.

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BACKGROUND: The role of gravity in the redistribution of pulmonary blood flow during one-lung ventilation (OLV) has been questioned recently. To address this controversial but clinically important issue, we used an experimental approach that allowed us to differentiate the effects of gravity from the effects of hypoxic pulmonary vasoconstriction (HPV) on arterial oxygenation during OLV in patients scheduled for thoracic surgery. METHODS: Forty patients with chronic obstructive pulmonary disease scheduled for right lung tumour resection were randomized to undergo dependent (left) one-lung ventilation (D-OLV; n=20) or non-dependent (right) one-lung ventilation (ND-OLV; n=20) in the supine and left lateral positions. Partial pressure of arterial oxygen (PaO2) was measured as a surrogate for ventilation/perfusion matching. Patients were studied before surgery under closed chest conditions. RESULTS: When compared with bilateral lung ventilation, both D-OLV and ND-OLV caused a significant and equal decrease in PaO(2) in the supine position. However, D-OLV in the lateral position was associated with a higher PaO2 as compared with the supine position [274.2 (77.6) vs. 181.9 (68.3) mmHg, P<0.01, analysis of variance (ANOVA)]. In contrast, in patients undergoing ND-OLV, PaO2 was always lower in the lateral as compared with the supine position [105.3 (63.2) vs. 187 (63.1) mmHg, P<0.01, ANOVA]. CONCLUSION: The relative position of the ventilated vs. the non-ventilated lung markedly affects arterial oxygenation during OLV. These data suggest that gravity affects ventilation-perfusion matching independent of HPV.

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The different concepts treating of "residual curarization" were presented according to two directions: the analysis of their contents--epidemiologic, clinical, instrumental--and the description of the pharyngeal striated muscles functions in these contexts. It appears that certain, too marked, "residual curarization" levels remain a well-evidenced factor increasing some morbidities in numerous clinical situations. All the methods of instrumental monitoring of the level of curarization--mecanography, electromyography, accelerometry--appeared useful to document the levels of "residual curarization" before patient's extubation or awakening. Today, for our speciality, it became particularly clear that: neither the selected muscle-- adductor pollicis--, neither the test currently privileged--train-of-four 2Hz--, nor the thresholds currently selected--0.90 or 1.00--did not constitute the unavoidable proof of a "residual curarization" complete absence. For the healthy volunteer receiving a curare, a train of four of the adductor pollicis greater than 0.90 can exist in presence of spirometric alterations evidencing the lack of adequate pharyngeal dilatation. In daily routine, the pharyngeal control is already disturbed by numerous molecules including: benzodiazepines, halogenated vapours, propofol, i.e. even under non-hypnotic concentrations. Faced to such evidences, our medical speciality will, undoubtedly, have to acquire new knowledge to develop muscle relaxant management control processes eliminating the surmorbidities related to "residual curarization". These tests must be validated also to exclude morbidity-prone dysfunctions of the pharyngeal striated muscles. Considering this new paradigm would be a major safety evolution for our speciality.

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BACKGROUND: As very strong agreement has been reported between bispectral index (BIS) values measured from the occipital and frontal skull areas, we compared BIS values measured from central and parietal areas with those from frontal area to investigate whether BIS is really a topographically dependent or topographically independent variable. METHODS: Twenty patients, ASA I-II, non-obese, aged 18-62 yr and with no neurological disorders were enrolled. Based on the 10-20 international landmarks, five silver dome electrodes were positioned: F7, C3, P7, Cz (common reference) and Fp1 (ground). Using frontal (F7-Cz), central (C3-Cz) and parietal (P7-Cz) electrode montages, the corresponding BIS values were simultaneously recorded with an Aspect A-1000 monitor (software v3.12). The BIS values were recorded at the propofol concentration allowing laryngeal mask insertion, which was maintained during the 10 min data collection period in absence of additional external stimuli. Data were analysed using the Kruskall-Wallis, Wilcoxon paired sign with Bonferroni correction, Bland-Altman and linear correlation tests. RESULTS: At the predicted effect target propofol concentration 4-8 microg ml(-1), the 10 min mean BIS (median [min-max]) were 32 [20-44], 46 [28-68] and 58 [41-72] for the frontal, central and parietal leads, respectively. Differences between these BIS recordings were statistically significant (P<0.0001, Kruskall-Wallis; P<0.005, Wilcoxon paired sign test). CONCLUSIONS: The present results provide evidence that BIS index is a topographically dependent variable in patients receiving propofol anaesthesia.

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BACKGROUND AND OBJECTIVE: The aim of this prospective study was to compare the effect of the administration of desflurane or sevoflurane to a fixed neuromuscular block. METHODS: After written consent, 12 patients were anaesthetized with propofol and sufentanil. Atracurium was administered via a continuous infusion in order to obtain 85% twitch depression of the control value assessed by repeated accelerometric stimulation at the adductor pollicis. Once stabilized over the course of 30 min, propofol was discontinued and either desflurane (n = 6) or sevoflurane (n = 6) was delivered at 1 MAC in a mixture of 50% O(2) in air. Study parameters were the magnitude and the time of twitch height variations. Results are presented in mean +/- SD. RESULT: Exposure to halogenated agents led to a significant reduction in twitch height with similar magnitude between the two agents. However, interaction with desflurane showed an initial and transient rise (35 +/- 22%) in twitch height before subsequent depression occurred. The time to reach 50% of the signal depression in the desflurane group was significantly delayed (25 +/- 7 vs. 11 +/- 4 min in the sevoflurane group; P < 0.01). CONCLUSIONS: On a stable neuromuscular block elicited by continuous infusion of atracurium, the abrupt administration of desflurane or sevoflurane reduces the accelerometric responses of the adductor pollicis in a similar way. This potentiating effect is produced faster after sevoflurane than after desflurane. With desflurane, a biphasic effect (of a transient and moderate increase followed by depression of the signal) was recorded.

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In this study we quantitatively evaluated, by a stable paralysis/stable infusion rate method, the difference between two standardized paralysis levels--train-of-four (TOF) count of 2 responses and posttetanic count (PTC) of 2. Ten ASA physical status I-II consenting adult patients scheduled for elective surgery were anesthetized (sufentanil/propofol), tracheally intubated, mechanically normoventilated with a fixed O(2)/air mixture, and normothermic; oropharynx and thenar temperatures were maintained above 36 degrees and 32.5 degrees C, respectively. After partial recovery from 200 microg/kg mivacurium (MIV), stable tactile TOF and PTC counts of 2 paralysis levels were induced on the adductor pollicis muscle by manual adjustments of an infusion pump containing MIV. The paralysis levels and the infusion rates were considered as stable once they remained constant at 4 consecutive time points separated by 5 min each. Infusion rates observed were: TOF count 2-6 (2-11) and PTC 2-17 (3-18) microg . kg(-1) . min(-1) (P < 0.001; Wilcoxon's paired comparison test). Under the present conditions, obtaining and maintaining a PTC of 2 requires MIV infusion rates far in excess of the "standard" recommendations mentioned in the literature for MIV infusion management.

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BACKGROUND: We measured lung mechanics and gas exchange during one-lung ventilation (OLV) of patients with chronic obstructive pulmonary disease, using three respiratory rates (RR) and unchanged minute volume. METHODS: We studied 15 patients about to undergo lung surgery, during anaesthesia, and placed in the lateral position. Ventilation was with constant minute volume, inspiratory flow and FIO2. For periods of 15 min, RR of 5, 10, and 15 bpm were applied in a random sequence and recordings were made of lung mechanics and an arterial blood gas sample was taken. Data were analysed with the repeated measures ANOVA and paired t-test with Bonferroni correction. RESULTS: PaO2 changes were not significant. At the lowest RR, PaCO2 decreased (from 42 (SD 4) mm Hg at RR 15-41 (4) mm Hg at RR 10 and 39 (4) mm Hg at RR 5, P<0.01), and end-tidal carbon dioxide increased (from 33 (5) mm Hg at RR 15 to 35 (5) mm Hg at RR 10 and 36 (6) mm Hg at RR 5, P<0.01). Intrinsic positive end-expiratory pressure (PEEPi) was reduced even with larger tidal volumes (from 6 (4) cm H2O at RR 15-5 (4) cm H2O at RR 10, and 3 (3) cm H2O at RR 5, P<0.01), most probably caused by increased expiratory time at the lowest RR. CONCLUSION: A reduction in RR reduces PEEPi and hypercapnia during OLV in anaesthetized patients with chronic obstructive lung disease.

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BACKGROUND: The predictive accuracy of target concentration infusions of propofol has been documented only for less than 4 h, and no prospective study of sufentanil target controlled infusion is available. The authors investigated the predictive accuracy of pharmacokinetic models for propofol and sufentanil coadministered during long-lasting surgery. METHODS: Ten patients, American Society of Anesthesiologists physical status I and II, were studied during extended cervicofacial surgery. Target controlled infusion of propofol and sufentanil was administered during surgery using decisional algorithms, taking into consideration pain assessment, hemodynamic changes, and peroperative blood losses. Intrasubject data analysis included calculation of performance error, median performance error, median absolute performance error, divergence, and wobble. RESULTS: The range of plasma target concentrations was 2-5 microgram/ml for propofol and 0.2-1 ng/ml for sufentanil. Median performance error was -12.1% for propofol and -10% for sufentanil. The wobble values were 11.6% and 22.3% for propofol and sufentanil, respectively. The pharmacokinetic sets used slightly overpredicted the concentrations, with negative values of divergence of 2.92% and 0.22% units/h for propofol and sufentanil, for a mean infusion period of 762 min. CONCLUSIONS: This prospective study demonstrates the predictive accuracy of the pharmacokinetic model for sufentanil infusion and confirms that for propofol during long-lasting surgery using standardized rules for the management of target controlled infusion and blood loss replacement.

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OBJECTIVE: To evaluate the prospective predictive accuracy and the quality of anesthesia of pharmacokinetic model-driven infusion of sufentanil and midazolam designed to establish and maintain a plasma level of drug during cardiac surgery. DESIGN: Prospective analysis. SETTING: Operating room at a university hospital. PARTICIPANTS: Twenty adult patients younger than 75 years old scheduled for valvular or coronary artery bypass graft surgery. INTERVENTIONS: Patients were anesthetized using a variable predicted concentration of sufentanil (1 to 10 ng/mL) combined with a stable predicted concentration of midazolam (100 ng/mL). MEASUREMENTS AND MAIN RESULTS: For each patient, arterial samples were taken before (6 samples), during (2 samples), and after (2 samples) cardiopulmonary bypass (CPB). Plasma sufentanil and midazolam concentrations were measured by specific radioimmunoassay and high-performance liquid chromatography techniques. Predicted sufentanil and midazolam concentrations were derived using the data sets of Gepts et al and Maitre et al. The predictive performance, the percentage prediction error (PE), and the absolute percentage error were calculated for each sample. The bias, inaccuracy, and dispersion were assessed by determining the median of the individual medians of the prediction errors (MDPE), the median of the individual median of the absolute prediction errors (MDAPE), and the 10th and 90th percentiles of PE. For midazolam, the inaccuracy was low (MDAPE < 21%), but CPB was associated with a dilution of the measured concentration associated with a negative bias. For sufentanil, the inaccuracy was also low before CPB (MDAPE = 18%) but increased during and after CPB (MDAPE > 40%). During the whole procedure, the hemodynamic control necessitated only a few interventions. CONCLUSIONS: Pharmacokinetic model-driven infusion of sufentanil and midazolam using the pharmacokinetic sets of Gepts et al and Maitre et al is a safe and accurate anesthetic technique before CPB in adult patients undergoing cardiac surgery when high sufentanil (1 to 10 ng/mL) and low midazolam (100 ng/mL) predicted plasma concentrations are targeted.

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UNLABELLED: We compared the effects of position and fraction of inspired oxygen (F(IO)2) on oxygenation during thoracic surgery in 24 consenting patients randomly assigned to receive an F(IO)2 of 0.4 (eight patients, Group 0.4), 0.6 (eight patients, Group 0.6), or 1.0 (eight patients, Group 1.0) during the periods of two-lung (TLV) and one-lung ventilation (OLV) in the supine and lateral positions. TLV and OLV were maintained while the patients were first in the supine and then in the lateral position for 15 min each. Thereafter, respiratory mechanical data were obtained, and arterial blood gas samples were drawn. Pao2 decreased during OLV compared with TLV in both the supine and lateral positions. In all three groups, Pao2 was significantly higher during OLV in the lateral than in the supine position: 101 (72-201) vs 63 (57-144) mm Hg in Group 0.4; 268 (162-311) vs 155 (114-235) mm Hg in Group 0.6; and 486 (288-563) vs 301 (216-422) mm Hg in Group 1.0, respectively (P < 0.02, Wilcoxon's signed rank test). We conclude that, compared with the supine position, gravity augments the redistribution of perfusion as a result of hypoxic pulmonary vasoconstriction, when patients are in the lateral position, which explains the higher Pao2 during OLV. IMPLICATIONS: This study compares oxygenation during thoracic surgery during periods of two-lung and one-lung ventilation with patients in the supine and lateral positions when using three different fraction of inspired oxygen values. Arterial oxygen tension was decreased in all three groups during one-lung ventilation in comparison with the two-lung ventilation values, but the decrease was significantly less in the lateral, compared with the supine position.

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The aim of this study was to measure the incidence of patients with train of four ratio < 0.9 in the immediate postoperative period using acceleromyography. At arrival in recovery room, 257 patients were enrolled. Train of four ratio was assessed at the adductor pollicis using TOF-GUARD INMT apparatus. Patients were divided in two groups according to TOF ratio < (group 1) or > (group 2) to 0.9. Demographic variables, dose (mg), dose/weight ratio (mg.kg-1) of atracurium and surgery duration (min) were registered. There was no difference in demographic variables, duration of surgery (100.90 +/- 67.38/94.83 +/- 62.42 min), number of incidence reversal of neuromuscular block. Patients in group 1 (n = 72) received a higher dose (54.58 +/- 38.03/41.43 +/- 19.47 mg) of atracurium compared to group 2 (n = 176). Thirty percent of patients presented a train of four ratio < 0.7 and 13% < 0.9. TOF-GUARD INMT was easy to use.

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UNLABELLED: We were looking for a clinical test to indicate a train-of-four (TOF) ratio of approximately 0.9. We compared the adductor pollicis muscle (AP) visually evaluated response to ulnar nerve 100-Hz, 5-s tetanus (RF100 Hz) with the measured AP TOF ratio in 30 ASA physical status I or II adult anesthetized (propofol, sufentanil, N2O/O2) patients. After the induction of anesthesia, the left ulnar nerve was stimulated at the wrist (single twitch and TOF) and the resultant isometric force was measured. When TOF was assessed, the independent investigators, unaware of the left AP-measured TOF ratios, visually evaluated the presence or absence of AP fading elicited by right ulnar nerve 100-Hz, 5-s tetanus. The 30 patients were randomly allocated to receive either 0.5 mg/kg atracurium (n = 15) or 0.1 mg/kg vecuronium (n = 15). The neuromuscular blockade was allowed to resolve spontaneously. A multiple logistic regression analysis was performed by computing the 771 visual observations. The probabilities of success of 100-Hz, 5-s tetanus to detect TOF ratios of 0.8, 0.85, and 0.9 were 99%, 96%, and 67%, respectively. The sensitivity and specificity of 100-Hz, 5-s tetanus as an indicator of TOF ratios of 0.85 and 0.9 are 100% and 75%, 54% and 67%, respectively. We conclude that RF100 Hz visual assessment seems to be highly sensitive in evaluating residual paralysis, as the absence of RF100 Hz visual fading at the AP is compatible with a TOF ratio > 0.85. IMPLICATIONS: After the administration of muscle relaxants, the absence of visual fading at the adductor pollicis, elicited in anesthetized patients by 100-Hz, 5-s tetanus, is compatible with a train-of four ratio > 0.85. Therefore, clinical observation of fading after 100-Hz, 5-s tetanus seems to be a highly sensitive test in evaluating residual paralysis.

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OBJECTIVE: To examine the effects of end-inspiratory pause (EIP) of different durations on pulmonary mechanics and gas exchange during one-lung ventilation (OLV) for thoracic surgery. DESIGN: A prospective clinical study. SETTING: A university hospital. PARTICIPANTS: Eleven patients undergoing elective pulmonary resection with pulmonary hyperinflation on their preoperative pulmonary function studies. INTERVENTIONS: Patients were anesthetized, paralyzed, and intubated with a double-lumen endotracheal tube. Their lungs were ventilated with a Siemens 900C ventilator (Siemens; Solna, Sweden), with constant inspiratory flow. Tidal volume, respiratory rate, and inspiratory time were kept constant during the study. MEASUREMENTS AND RESULTS: During one-lung ventilation in the lateral decubitus position, three levels of EIP (0%, 10%, and 30%) were applied to the dependent lung in random order. After 15 minutes on the given ventilatory pattern, end-inspiratory and end-expiratory occlusions of at least 5 seconds were performed to obtain respiratory mechanics data. Arterial blood gas samples were drawn to assess gas exchange. Altering the duration of end-inspiratory pause from 0% to 30% resulted in a significant increase in intrinsic positive end-expiratory pressure (PEEPi) from 4.1 cm H2O to 7.0 cm H2O. Arterial oxygenation was significantly decreased from 109.7 to 80.5 mmHg and there was a significant negative correlation between the value of partial pressure of arterial oxygen (PaO2) and PEEPi by altering the duration of end-inspiratory pause. From the preoperative pulmonary function studies, the value of functional residual capacity (FRC) (% predicted) showed a significant negative correlation with the PaO2 changes. Partial pressure of arterial carbon dioxide (PaCO2) was not altered significantly by increasing the duration of end-inspiratory pause. CONCLUSION: During the period of OLV in the lateral position of patients with preexisting pulmonary hyperinflation, the magnitude of PEEPi increased and oxygenation decreased significantly, whereas the efficacy of ventilation was not changed by the addition of an end-inspiratory pause to the ventilatory pattern. Because arterial oxygenation is affected by the presence of pulmonary hyperinflation, the method of ventilation should take into account the magnitude of preoperative pulmonary hyperinflation.

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UNLABELLED: We studied patients undergoing elective pulmonary surgery to establish whether observing interrupted expiratory flow (IEF) on the flow-volume curves constructed by the Ultima SV respiratory monitor is a reliable way to identify patients with dynamic pulmonary hyperinflation and intrinsic positive end-expiratory pressure (PEEPi). Patients' tracheas were intubated with a double-lumen endotracheal tube and ventilated with a Siemens 900C constant flow ventilator. In 30 patients, PEEPi was determined by the end-expiratory occlusion (EEO) method during the periods of two-lung and one-lung ventilation in the lateral position. Sensitivity, specificity, positive and negative predictive values, and diagnostic accuracy of the IEF method were calculated. From the 122 measurement pairs, PEEPi was identified with the EEO method in 65 occasions. The mean level of PEEPi was 4.4 cm H2O. During one-lung ventilation, the level of PEEPi and the number of true-positive findings was significantly higher (PEEPi = 4.7 cm H2O and 32 episodes) than during two-lung ventilation (2.9 cm H2O and 19 episodes). When the level of PEEPi was higher than 5 cm H2O, the predictive value of IEF was 100%. The overall sensitivity of the IEF method was 0.78, its specificity was 0.91, and its predictive value was 0.92. In conclusion, examination of the flow-volume curves displayed on the respiratory monitor may identify patients with dynamic hyperinflation and PEEPi during anesthesia for thoracic surgery. IMPLICATIONS: To identify patients with intrinsic positive end-expiratory pressure during anesthesia without the need to interrupt mechanical ventilation, the flow-volume curves of an online respiratory monitor may be examined. The presence of an interrupted expiratory flow may suggest the presence of intrinsic positive end-expiratory pressure with a reasonable accuracy.

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We have investigated the pharmacokinetics and pharmacodynamics of propofol in 11 patients with end-stage renal disease (ESRD) compared with nine healthy patients during and after a manually controlled three-stage infusion of propofol 21, 12 and 6 mg kg-1 h-1 lasting a minimum of 2 h. Mean total body clearance was not reduced significantly in the ESRD group (30.66 (SD 8.47) ml kg-1 min-1) compared with the control group (33.75 (7.8) ml kg-1 min-1). ESRD patients exhibited a greater, but not statistically significant, volume of distribution at steady state compared with patients in the control group (11.25 (8.86) vs 5.79 (2.14) litre kg-1, respectively). Elimination half-life values were unchanged by renal failure. Mean times to induction of anaesthesia were similar in both groups: 177 (SD 57) and 167 (58) s for the ESRD and control groups, respectively. Waking time after cessation of propofol infusion was significantly shorter in the ESRD group (474 (156) s) compared with the control group (714 (240) s) (P < 0.05). Mean plasma concentrations on waking were similar. We conclude that the pharmacokinetic and pharmacodynamic profiles of propofol after infusion were not markedly affected by renal failure.

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STUDY OBJECTIVE: To evaluate a range of doses of intravenous (i.v.) dolasetron mesilate, in preventing postoperative nausea and vomiting (PONV). DESIGN: Double-blind, placebo-controlled, randomized, multicenter trial. SETTING: Ten hospitals and/or surgical centers. PATIENTS: 281 women undergoing gynecologic surgery with general anesthesia. INTERVENTIONS: Patients received one of four single, i.v. doses of dolasetron mesilate (12.5 mg, 25 mg, 50 mg, and 100 mg) or placebo administered following cessation of anesthesia. MEASUREMENTS AND MAIN RESULTS: Patients were monitored for 24 hours following study drug administration. The antiemetic efficacy of each dolasetron mesilate dose was evaluated by recording the number and timing of emetic episodes, and the effects on nausea were assessed by use of visual analog scales (VAS). Safety was assessed by adverse event reports, clinical laboratory tests, electrocardiographic (ECG) measurements, and monitoring vital signs. Complete responses (patients with no emetic episodes and no escape antiemetic medication requirements in 24 hours) were achieved by 54% in the 12.5-mg, 67% in the 25-mg, and 59% in both the 50-mg and 100-mg dolasetron mesilate dose groups, and by 43% in the placebo group. Nausea VAS assessments demonstrated that dolasetron-treated patients were significantly (p = 0.048) more likely to report no nausea (VAS score < 5 mm) than those in the placebo group. Adverse events reported generally were mild in intensity, and there were no clinically significant changes in laboratory tests, vital signs, or ECG parameters. CONCLUSIONS: Dolasetron was effective and well tolerated for the prevention of PONV in female patients undergoing gynecologic surgery with general anesthesia.

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OBJECTIVE: During surgery, computers can be of great use to support the anesthesiologist in providing task automation. In this paper we describe a closed loop blood pressure controller and show the results of its clinical evaluation. METHODS: The controller is based on a simple and robust Proportional-Integral controller and a supervising, rule based, expert system. Adaptive control is necessary because the sensitivity of the patients to sodium nitroprusside varies over a wide range. Thirty-three clinical tests during cardiac surgery, including the cardiopulmonary bypass phase, were performed. RESULTS: On average the controller was in automatic mode for 90.6 +/- 9.6% of the time. The performance during automatic control showed the mean arterial pressure to be within 10 mmHg of the setpoint for 71.4 +/- 15.5% of the time. The average absolute distance to the setpoint was 8.1 +/- 7.2 mmHg. CONCLUSIONS: The overall performance of the controller was noted as very satisfactory by the anesthesiologists.

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