Biomedical subjects
Publications and source records attributed to A Neidhardt.
The contamination of air of a 50 m3 operating room has been analyzed after three and half hours of halothane enaesthesia with a closed circle system and an opened system. The analysis has been made by gaz chromatography. Concentrations of Halothane found during the use of an opened system are 100 to 120 times the allowable norms in U.S.A. After using the closed circle system, the analysis of air does not reveale any trace of Halothane.
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The purpose of this study was to verify the statements of Blackburn concerning the positive effects of strict nitrogen hypocaloric diets. Three groups of 10 postoperative patients received hypocaloric diets. A carbohydrate diet of 200 grams was given to the first series of patients, a nitrogen diet of 12.4 to the second and finally a carbohydrate-protein diet consisting of 200 grams Sorbitol and 12.4 grams nitrogen to the third. Patients were followed for five days. The existence of post-aggression reactions was determined through measurements of GH, Cortisol, glycemia, insulinemia, fatty acids and ketone bodies. Patients under the strict nitrogen diet presented a less elevated hyperglycemia than the other groups. Insulinemia was also lower with values returning to normal by the second day. This same group showed a significant rise of free fatty acids with ketonemia, an obvious sign of lipolysis. The respiratory quotient, near 0.7, was also indicative of lipolysis. The cumulative nitrogen balance over five days was much less negative than for patients under a strictly carbohydrate diet: the nitrogen balance closest to zero was however obtained for patients under the carbohydrate-protein diet. The combined analysis of the respiratory quotient and the nitrogen balance allowed an evaluation of the respective participation of lipid and carbohydrate nutriments to the energy supply in function of the three types of diet. Lipid participation was of 36% under the carbohydrate diet, 48% under the carbohydrate-protein diet and 84% under the strictly protein diet.
A microcomputer type 6502 is the central unity of a volatile anaesthetic injector for use in a closed circuit breathing system. Estimated calculations for quantity of anaesthetic liquid are done in agreement with the formula of J.W. Severinghaus and H. Lowe. Clinical assay is realised with enflurane. The syringe efficacy is controlled by permanent recorder of halogenate concentration in upper airways Fi-FA: infrared analysor cosma Rubis 3000).
Independent lung controlled ventilation by a double lumen tube has a beneficial effect in oesophagus surgery. Use of a tidal volume and an end-expiratory pressure different for each lung produces a drastic reduction of chest-X-ray abnormalities. In an homogen group of ten patients studied before and treated with conventional respiratory support, chest-X-ray abnormalities were seen in 80% cases. In this group of 34 patients treated with independent lung ventilation the rate of abnormalities is only of 20%. Independent lung ventilation decreases early pulmonary complications in dependent regions of the lungs, and late pulmonary complications in non dependent regions. This form of mechanical ventilation is performed with a "prototype" ventilator of small size, which permits synchronized or independent ventilation of the lungs.
The object of Halothane Meter (HM) study is to estimate its reliability (accuracy and stability) and its possible effect on the degradation of the molecule by the action of the UV (254 nm). The zero instability of the apparatus, clinically evident, is due to the constructor who undertakes to modify it. The molecule analysis, treated in vivo (4 hours of anesthesia) and in vitro by irradiation respectively by the HM (cathodeon 254 nm) and a source of some wavelength UV is realised by UV spectrophotometry, IR spectrophotometry, RMN spectrometry. The results of all analysis allow to exclude the molecule degradation which could impede the recirculation of treated gas in a closed circle.
The ventilatory effects of tramadol (T) and nefopam (N) are evaluated in anesthetized patients with enflurane in a closed circuit breathing system and compared with the effects of pentazocine (P). The following parameters tidal volume (VT), minute ventilation (V), CO2 (capnometry) occlusion pressure (OP), ventilatory response to hypercarbia are recorded after 30 minutes of anaesthesia, before and after repeated injections of the analgesics, P: 15 mg, N: 40 mg, T: 100 mg are injected I.V., and analgesics administration is repeated at 30 minutes interval, so that the patients receive a total P dose of 30 mg, a total N dose of 60 mg and a total T dose of 200 mg. The administration of 15 mg of P induces a change in VT (-24%), ventilatory frequency (-40%), OP (-18) OP only returns to basal values after a second dose. The ventilatory response to hypercarbie is indeed satisfying (increase of 61% in V). After N and T, ventilatory frequency is not disturbed. V increases of 16% and 11% respectively after the first injection, and of 31% and 2% after the second injection. OP increases by 39% and 56% respectively after the first injection and gets better over time with nefopam (+ 58%), 30 mg of P. 20 mg of N and 100 mg of T are equivalent for analgesia.(ABSTRACT TRUNCATED AT 250 WORDS)
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A pump is used to reinsert the expiratory gas of a Bain Spoerel system into the circuit. It delivers a 14 l.min-1 flow. The expiratory gas is drawn across a CO2 absorber and fresh gas flow is reduced to the patient's VO2. The technic cumulates the advantages of the closed system to the Bain Spoerel system: practical design for head surgery, no valve, then less energetic loss by the patient in spontaneous ventilation, convenient gas flow, adapted to the small child, because of small dead space, economy of drugs, ecology: no more pollution ! humidification and warming of inspired gas. A hundred patients have been so anaesthetized in head surgery without any problem.
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The peroperative pulmonary compliance in spontaneous ventilation is studied in two series of ten anesthetized patients with halothane and enflurane, in closed system. The tidal volumes (inspiratory and expiratory at noflow point) are recorded by pneumotachograph (Godard 17212). The intrathoracic to mouth differential pressure is recorded by pressograph (Godard 17300). The measurements are simultaneously realized by linear recorder (Brush gould 2500) or by XY recorder (Bryans 26000 A4). At the second hour of anaesthesia with enflurane pulmonary compliance is not modified (non significant increase to 11,5 p. cent: 0,3 less than P less than 0,2) while with halothane it shows a very significant 25 p. cent decrease (0,001 less than P less than 0,01). The authors relate this difference to the specific feature of breathing in the course of such an anaesthesia with enflurane.
This adaptation presents the following advantages over and above those already acknowledged for continuous IPP ventilation: conservation of respiratory muscle functions, autoregulation of ventilatory frequence, reduction of mean endothoracic pressure, thus dispensing with the necessity for negative-end-expiratory pressure. In addition: easy, effortless assembly, abolishes the defects of the Bennett PR2, gives the machine a good volumetric performance.
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The prevention of tracheal lesions due to the ballons of the intubation catheters depends on the correction of several factors concerning: -the material used (polyvinyl is better tolerated than rubber); -the shape (the sleeve-shape balloons are less traumatic); -the pressure of use, which should remain moderate; -the permanence of the compression (one should use intermittent filling of the ballon). A device designed by the authors and which is described here, permits intermittent insufflation of the ballons of the endotracheal catheters, by adaptation of certain apparatus of artificial ventilation, type LOGIC and SF4, has given excellent results.
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