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Biomedical subjects

A Neidhardt

Publications and source records attributed to A Neidhardt.

At least 19 recordsLinked to original sources
PubMed1992

[Choice of respirators for anesthesia].

Criteria of quality of gases and vapours supply, ventilator, patient's circle circuit and monitoring devices are recalled to help the anesthetist to choose his anesthesia machine. Advantages of compact or modular apparatus are discussed. Four, now wellknown, anesthesia machines (modulus II+, Siemens 900 D+SAC985, Roche Kontron 4300 and Engstrom Elsa) were analysed in clinical controlled ventilation and in simulated spontaneous ventilation to study the imposed work of breathing. Results are discussed with regard to safety rules and to ergonomics, bearing in mind their respective prices. Comparison is made with an original "bisontin" prototype.

Anesthesia, Inhalation↗
PubMed1992

[Automatic measurement of blood pressure: limits of oscillometric technique].

Non invasive blood pressure (NBP) measures are currently used in anesthesiology. The accuracy of this oscillometric technic has been tested with healthy patients, but not often with a wide pattern of pathology. The aim of this study is to point out the reliability of NBP during vascular surgery with patients suffering from arterial disease and atherosclerosis. It compares outcome with simultaneous catheter arterial blood pressure measurement (template technic). In this conditions, oscillometric method underestimates the systolic pressure value, and overestimates the diastolic one. The higher the level of arterial pressure is, the larger is the difference between this methods. It is clear that the automatic oscillometric technic is not so reliable if hypertension or atherosclerosis disease occurs. In order to improve this technic, automatic measures must take in account the degrees of arterial rigidity in its outcome.

Automation↗
PubMed1992

[Considerations on the monitoring of soda lime. Consideration technique].

The choice of ethyl violet as a pH indicator in soda lime is not the best. Color change happens too late because pH alteration of the surface of soda lime is slower than in the core of the canister. Clinical and comparative measurement of wall temperature of two in series canisters is a good precaution. If the down stream canister is warmer than the upstream one, you must change the latter.

Anesthesia, Closed-Circuit↗
PubMed1992

[High frequency jet ventilation in heated gas saturated in water vapor without a reserve of medical gas under pressure. An original method].

A prototype of high frequency jet ventilator is compared with a classic device: Gambro Soxijet ventilator. The advantages of the prototype are: no need of pressured medical gas; warming and saturated moisture of the gas. A powerful compressor (2 M3.H-1 flow--3 bar pressure) draws up the moistened and warmed gases and injects them into a double pneumatic capacity. The first capacity is pressure limited by a relief valve (3 bar). Exhausted gases flow back to the pump. A miniature pressure regulator, placed between the two capacities, rules the driving pressure. Gas mixture is injected through a solenoid valve controlled by an electronic twin-timer. Results of both devices are similar. However, our prototype seems to be very convenient for developing countries where medical gases under high pressure are not often available.

Developing Countries↗
PubMed1992

[An analgesic strategy for tympanoplasties].

UNLABELLED: After induction with vecuronium, etomidate and then isoflurane or enflurane, nitrous oxide, useful at the beginning of tympanoplasty is washed out before the end of operation. So barotrauma on the graft is avoided. In the expectation of analgesia insufficiency, alfentanil is infused intravenously all over the operation period following two modes: constant flow mode (1.25 micrograms.kg-1.min-1) after a bolus (25 micrograms.kg-1): 33 patients; decreasing hyperbolic flow mode (H): cumulative dose = 10.8 x t0.5 (where t = minutes of infusion) = 47 patients. In this mode, plasma concentration is measured by 12 patients. RESULTS: the mean plasmatic level of alfentanil is steady during the 120 minutes duration of anaesthesia: standard deviation is higher than 30%. After high quality anaesthesia in both technics, recovery time was shorter with H mode than with constant flow one (extubation time = 46 +/- 31 min. versus 92 +/- 54 min). H. mode seems to be safer. Though, individual reactivity, drug interaction and genetic polymorphism must make us cautious! Two patients presented apnea 20 and 60 minutes after an efficient awakening.

Adult↗
PubMed1992

[The reliability of slow flow isoflurane vaporizers].

Two new vaporizers for isoflurane were tested and verified with very low flows: Ohmeda Tec 5 and Penlon PPV Sigma vaporizers. This work completes a previous one [1]. The Ohmeda Tec 5 appeared to be quite reliable. The Penlon vaporizer gave pretty good results too. However a gas flow with vibratory component can affect the result by decreasing dramatically the concentration of inhaled isoflurane.

Anesthesia, Inhalation↗
PubMed1991

Structural dynamics in F1ATPase during the first reaction cycle of ATP hydrolysis.

The velocity of ATP hydrolysis, catalyzed by purified F1ATPase from Micrococcus luteus, was decelerated on decreasing the temperature. At 13 degrees C one reaction cycle is completed after 20 s. Hydrolysis was triggered upon rapid mixing of the enzyme with ATP. During the first reaction cycle, succeeding structural alterations of the F1ATPase were traced by time resolved X-ray scattering. The scattering spectra obtained from consecutive intervals of 1 s, revealed the F1ATPase to pass a conformational state exhibiting an expanded (6%) molecular shape. The expanded state was observed between 45% and 65% of the time required to complete the reaction cycle. This points out a conformational pulsation during ATP hydrolysis.

Adenosine Triphosphate↗
PubMed1991

[Emergency anesthesia with halothane-air. Techniques; indications; limits].

A new apparatus for anaesthesia has been developed for disaster situations. A turbine pushes room air through a halothane vaporizer to a modified D. Mapleson system. A battery provides an autonomy of two hours with an air flow of 5 liters per minute. Electrical current used is 220 volts external or 12 volts. Oxygen can be added during inductions and when there is imbalance in the hemodynamic or respiratory function. One series of 20 patients successfully underwent this procedure. Oxygen monitoring was performed with percutaneous PO2, SaO2, FiO2. Only one patient with cardiac disease needed oxygen adjonction (2 l.min-1) to raise his SaO2 level above 95%. Thus it is possible to have the optimum FiO2 with the lowest amount of halothane and oxygen.

Air↗
PubMed1991

[Arrhythmia in anesthesia and intensive care].

There is a high incidence of dysrhytmias in the operating room and I.C.U. Calling again diagnosis criteria using common leads of the E.E.G. leads to suggest a treatment approach taking the main effect of non cardiac factors in account, before the use of antiarrhythmic drugs. The Puech classification takes many data into consideration: electrophysiological properties, cardiac disease and trigger mechanism of dysrythmias. So, it is a better practice in a dysrythmia therapy to examine all these characteristics in order to choose an adjusted treatment.

Anesthesia, General↗
PubMed1990

[Closed-circuit anesthesia in children].

The aim of this study is to demonstrate how easy and suitable is the closed system in infants and children. An original circuit, adapted from the Bain-Spoerel system, is used. Its principle is to draw-up the expired gas through a soda lime canister by a pump, whose flow is 14 l.min-1. ("Circuit Bisontin"). For this study, 20 infants and children underwent anesthesia with isoflurane, in spontaneous or mechanical ventilation (with a "bag in the bag" principle ventilator). The lowest body weight was 2.7 kg. The advantages are a minimal dead space and no expenditure of energy during spontaneous ventilation thanks to an internal high flow and the absence of internal one-way valve. Gas monitoring is achieved by a four gas analyser (Capbomac Datex).

Adolescent↗
PubMed1990

[Value of the radionetwork of the transportation company in Besançon for alarm forwarding].

The C.B. users offered for a few years a way for putting-out the distress on the highway. There were 2,000 in Besançon and surroundings in 1982. Today they are becoming no existent. Since then a new system of alarm run is born with 150 buses, 178 kilometers of net-travel and a sweep frequency of 10 min from 6h30 a.m., to 8h p.m, and of 30 min until 12h p.m. The 250 "C.T.B." drivers assume a regular surveillance of the urban and suburban highways. A standard message in used between the C.T.B. (Besançon Company of Buses.) regulation and Samu 25, regulation which allows to fix circumstances, place of road accident and inventory of casualties: 27 emergency calls are received in 1987, 50 in 1988. It might be possible to use other private or public radiotelephonic network.

Communication↗
PubMed1990

[Repetitive inhalation anesthesia in rats].

Inhalational anesthesia in the rat seems a good process, by a rapid induction and awakening if a steady state ventilation-perfusion ratio and no pollution are obtained. Animals are cooped up in an "induction-box" which is joined to a scavenger system. Anesthesia maintenance is assumed with a Bain circuit and allows short and frequent anesthesia. Isoflurane does not markedly decrease circulatory and respiratory factors at low concentration (2%). So any anaesthetist can do himself such a practical system.

Anesthesia, Inhalation↗
PubMed1990

[Flumazenil and volatile anesthetics. Study of possible interferences in rats].

Many works suggest contradictory experimental or clinical results of flumazenil effects during inhalation anaesthesia. In ten rats anaesthesia was induced with 5% isoflurane or halothane during one minute and maintained during 5 minutes with 1% the same halogene anaesthetic in 50% N2O and O2. Then 0.2 mg of flumazenil or a same volume of placebo were administered intraperitoneally and during the last 5 minutes, the rats were exposed in 1% volatile anesthetic gas flow. Sleep times were measured in terms of reestablishment of the righting reflex. Each rat was anesthetized four time: halothane and isoflurane, with flumazenil or placebo. In those conditions, there were no significant changes in sleep times either the anaesthesia were associated, with flumazenil or with placebo.

Anesthesia Recovery Period↗
PubMed1990

[The indirect calorimeter, "do it yourself"].

An original metabolic calculator is realized with common and fiable transducers: a "microgaz Roche Kontron 7640" gives the PiO2-PeO2 and PeCO2 (Clark and Stow Severinghaus electrods), a pneumotachograph Gould 17212 (or the reliable integrated flow meter of the respirator) gives the expiratory minute volume. These values are inserted in an micro computer (Sharp PC 1261). The soft is wrote so that results are not altered when high FiO2 are used. Consumption of lipids and glucids is displayed in percentage when diuresis and urea values are entered. This device is compared with a well known expenditure monitor: Deltatrac (Datex): simultaneous measures are carried out in patients with miscellaneous diseases (15 series of 10 measures). Regression curves appear to be very reliable, as well for VO2(r = 0.98), VCO2 (r = 0.94) energy expenditure (0.97) as for R.Q (r = 0.77).

Calorimetry↗
PubMed1989

[Monitoring of gases and vapors in the anesthesia system].

By now inhalation anesthesia makes anesthetic gaz and vapours analysis compulsory. This paper give an account of numerous gaz analyzers which are available today. Different kinds of oximeters (galvanic, polarographic, paramagnetic) carbon dioxide analysers, halothane, enflurane or isoflurane-meters are reviewed. Advantage/cost ratio of mass spectrometer is discussed too. Practical advices on use and site of slow and fast analysers are recalled.

Anesthesiology↗
PubMed1989

[Flowmeters and safety rotametric mixers].

Rules and principles in choice of flowmeter take in account the advices of French National Approval Committee. Several and more frequently used and modern flowmeters are discussed, authors wishing an European harmonization of the safety guidelines in anaesthesia for 1993.

Anesthesiology↗