Slope effect on pushing forces.

In some occupations pushing forces are frequent when performed on horizontal ground and are standardized (ISO 2002). In special cases employees are obliged to grow container on slopes and the strains are poorly investigated. The objective of this work is to measure forces required to push garbage container on horizontal and inclined at 0, 4, 11 and 16 % grounds. Sudden and significant increases in heart rate reflect the possible risk of heart overload in long displacements. This study proposes realistic limits and provides a simple and protective tool for a group of employees without distinction of age or gender. These limits can even be reduced to a quasi-linear model where push 200 kg is the maximum for 0% slope and 60 kg for 10% slope.

Comparison of physiological and subjective strains of two protective coveralls in two short physically simulated demanding tasks.

A total of 15 physically active male students carried out a normalised task (T(N)) and a task of access by ladder and scaffolding (T(L)) in two impermeable protective coveralls and a reference sports wear to compare the physiological and subjective strains. Heart rate (HR) was recorded and sweat loss was checked. Subjective evaluations of comfort parameters, acceptable exposure durations and physical exhaustion were recorded at the end of the tasks. Results show that both protective clothing, compared to the sport wear, increase significantly HR, RPE and CR10 in both tasks. However the strains of both protective clothing are not significantly different except in sweat loss and cumbersomeness.

Comparison of physiological and subjective strain in workers wearing two different protective coveralls for asbestos abatement tasks.

The aim of this study was to compare the physiological and subjective strain in workers wearing a disposable "Tyvek" (TYV) and a ventilated "Mururoa" (MUR) coverall in a real working situation. Eleven men performing normal abatement tasks volunteered to participate. Physiological measurements included oral temperature, heart rate and sweat loss. Subjective evaluations of clothing comfort, cooling, robustness, cumbersomness, acceptable exposure duration and physical exertion were carried out at the end of the task. The ventilated MUR reduced heat strain. Indeed, it allowed significantly higher sweat loss than TYV and showed a tendency to reduce the increase in oral temperature. Subjective ratings reveal that MUR was considered better than TYV in terms of clothing comfort, coolness and robustness. On the other hand, MUR is more cumbersome to wear. In this study, where workload and heat stress were moderate, there were few differences between the two coveralls in terms of physiological strains, but far more significant differences in the subjective ratings.

Fluoride excretion in children after sevoflurane anaesthesia.

BACKGROUND: Defluorination of sevoflurane is catalysed by the hepatic enzyme cytochrome P450 2E1 (CYP2E1). Data about the ontogenesis (developmental variations in activity) of this enzyme suggest a low metabolism of sevoflurane during the first months of life. METHODS: To test this hypothesis, 45 children less than 48 months of age undergoing sevoflurane anaesthesia were enrolled in a prospective open clinical trial. The 24 h urine fluoride excretion was measured in five groups of children (A, <4 months; B, 4 to <8 months; C, 8-12 months; D, >12-24 months; and E, >24-48 months old). An index of sevoflurane metabolism (ISM) was calculated as the ratio of fluoride excretion, cumulative expiratory sevoflurane concentrations measured every minute during anaesthesia, and body surface area. ISM values were median (IQ 25-75%). RESULTS: ISM was lower in group A (n=9, 18.9 (11.2-29.5) than group C (n=11, 44.2 (37.5-53.5), P<0.05), group D (n=7, 52.6 (45.8-68.4), P<0.01) and group E (n=9, 53.6 (50.7-85), P<0.001). Median ISM expressed as a function of median age, exponentially increased with a rapid increase during the first months of life, followed by a slower increase after 10 months of age. CONCLUSION: These results suggest that, in children less than 48 months, sevoflurane metabolism parallels postnatal development of CYP2E1.

[Anesthesia for cesarean section in a patient with McArdle disease and hereditary dilated cardiomyopathy]. / Anesthésie pour césarienne chez une patiente atteinte d'une maladie de McArdle et d'une cardiomyopathie dilatée familiale.

A caesarean section was indicated in a 29-year-old parturient affected by a muscular deficit in myophosphorylase responsible for a type V glycogen storage disease (McArdle disease). This metabolic myopathy had been diagnosed two years previously, whereas the patient already suffered from a hereditary form of dilated cardiomyopathy. The muscular disease was invalidating on the functional level with exercise intolerance. The cardiopathy was little symptomatic but the dysfunction of the left ventricle worsened during the pregnancy with an ejection fraction calculated to 43%. In this case, we report the realization of a general anaesthesia in a patient who had epidural anaesthesia for a previous caesarean section.

Does sevoflurane inhibit serum cholinesterase in children?

Serum cholinesterase activity was measured at induction, and following anaesthesia in 41 children aged between 4 and 30 months. The median exposure to sevoflurane was 273%.min. The results did not demonstrate any significant difference in cholinesterase activity, when expressed by gram of serum proteins following inhalation anaesthesia using sevoflurane or intravenous anaesthesia using propofol. The values (SD) obtained were 175 (42) UI.g(-1) before anaesthesia and 177 (43) UI.g(-1) following anaesthesia. The only change in cholinesterase activity detected was related to heamodilution. We conclude that plasma fluoride concentration following sevoflurane administration [13.8 (4.2) microm x l(-1)] is too low to exert an inhibiting effect on in vivo cholinesterase activity and that the previously reported decrease in mivacurium requirements during sevoflurane anaesthesia is unlikely to be due to inhibition by fluoride ions.

[Diaphragmatic excursion after inter-sternocleidomastoid block depending on the site of the injection]. / Course diaphragmatique après bloc inter-sterno-cléido-mastoïdien, en fonction du site d'injection.

OBJECTIVE: To evaluate the incidence of the hemidiaphragmatic paresis after inter Sterno-Cleido-Mastoid (inter-SCM) block. STUDY DESIGN: Prospective, comparative, single blind study. PATIENTS: 16 patients ASA I-II. METHODS: The diaphragmatic paresis was measured by a radiologist unaware of the technique used and operated side. It was determined by the diaphragmatic excursion (DE) on double-exposure chest radiography, obtained preoperatively and postoperatively (DE-pre, DE-post) for the ipsilateral and controlateral side of the inter-SCM block. All the patients were given 20 mL 0.5% bupivacaine plus 20 mL 2% lidocaine both with epinephrine. These anesthetics were injected via the stimuling needle or via the catheter after opacified radiological control of the catheter position. The patients were divided into 2 groups. Group 1: injection via the needle after eliciting flexion of fingers, or via a catheter into infraclavicular position; group 2: injection via the needle after eliciting contraction of deltoid, or elbow flexion, or via a supraclavicular catheter. RESULTS: All the patients had satisfactory block. The ipsilateral DE was decreased after injection of anesthetics in group 2 (P < 0.001) while it remained unchanged in group 1. CONCLUSION: The diaphragmatic paresis is avoidable with the inter-SCM block if and only if the anesthetic solution is injected via the needle after stimulating flexion of fingers or via a catheter into infraclavicular position.

[The use of propofol does not increase the cost of the management of patients in heart surgery with extracorporeal circulation]. / L'utilisation du propofol n'augmente pas le coût de la prise en charge des patients lors de chirurgie cardiaque avec circulation extracorporelle.

OBJECTIVES: Evaluation of the cost of propofol used for fast-track in cardiac surgery and its impact on global cost of management for anaesthesia and intensive care. STUDY DESIGN: Case-control study, prospective (1998) and retrospective (1994). PATIENTS: Twenty patients operated for cardiac surgery in 1998 and scheduled for fast-track anaesthesia. Twenty patients in 1994 matched for different criteria to the patient of 1998. METHODS: In 1998, all drugs, materials used and X-rays, biochemical assays performed were prospectively collected and their cost calculated. In 1994, similar calculations were done retrospectively. Comparison of duration of mechanical ventilation, hospitalization in intensive care and in the hospital were performed. RESULTS: Cost of anaesthesia was similar in 1994 and 1998 (2,646 FF versus 2,294 FF). Global cost of management was significantly lower in 1998 in comparison to 1994 (5,439 FF versus 8,558 FF). Duration of mechanical ventilation, hospitalization in intensive care and in the hospital were shorter in 1998 than in 1994. CONCLUSION: Despite a higher cost of propofol for anaesthesia and postoperative sedation in comparison to midazolam, the global cost of management decreased significantly in relation to a one day decrease in hospitalization in the intensive care unit.

Affinity of mouse immunoglobulin G subclasses for sialic acid derivatives immobilized on dextran-coated supports.

High-performance liquid affinity chromatography is a powerful method for the purification of biological compounds owing to its specificity, rapidity and high resolution. In our laboratory, we develop chromatographic supports based on porous silica beads. However, in order to minimize non-specific interactions between the inorganic surface and proteins in aqueous solution, the silica beads are coated with modified dextran. As previously reported, many affinity ligands can be covalently grafted onto dextran-coated silica. In this study, N-acetylneuramic acid, which belongs to the sialic acid family and is present in immunoglobulin G (IgG) epitopes, is used as an active ligand. The interactions of this affinity support and IgG subclasses are analyzed. This immobilized ligand enables purification of IgG3 antibodies.

High-performance affinity chromatography of insulin on coated silica grafted with sialic acid.

High-performance liquid affinity chromatography (HPLAC) is a powerful method for the purification of biological compounds, owing to its specificity, speed and high resolution. We developed new chromatographic supports based on porous silica beads. In order to minimize non-specific interaction between the silanol groups at the silica surface and biological molecules, the beads are coated with dextran carrying a calculated amount of positively charged functions. Such supports have the mechanical properties of the starting inorganic material. Moreover, they can be easily activated and functionalized by active ligands using conventional coupling methods. In the present study, N-acetylneuraminic acid (NANA), a member of the sialic acid family, is coupled to dextran coated silica beads to obtain affinity supports. This class of compounds seems to play an important role in the cell recognition mechanism. In particular, sialic acids are present in the structure of the cellular receptors for insulin. By HPLAC, we can study the interactions between coated silica grafted with NANA and insulin. It is also possible to use these active supports to purify the compounds by affinity chromatography. However, it is important to determine and optimize the conditions for adsorption and desorption of insulin on supports grafted with sialic acid and to estimate the chromatographic performances of these active phases.