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Biomedical subjects

A Neidhardt

Publications and source records attributed to A Neidhardt.

At least 37 records · Page 2Linked to original sources
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↗
PubMed1987

[Programmed injection of liquid volatile anesthetics into the system. A plea for a tightly closed circuit].

Severinghaus et Lowe have given us a precise means of knowing what the patient's anaesthetic needs are under volatile anaesthesia. The parameters of the well-known formula for calculating the unit dose, Qan = 2 [Qc (dl).lambda.1.3 MAC], are recorded in the microprocessor of a computerized syringe: 1) the patient's body weight to the power 0.75 and multiplied by 2, i.e. cardiac output (Qc); 2) the nature of the selected volatile, i.e. the product of elements other than the Qc. The microprocessor calculates also the rate per minute according to the information obtained from the clock and the principle that the rate of anaesthetic is inversely proportional to the square root of the time the anaesthesia lasts. A numerical panel gives information on the following: injection time, injected anaesthetic volume per minute, cumulative quantity of liquid anaesthetic injected. The syringe is set in such a manner as to face upwards to prevent the development of bubbles. A rapidly stable alveolar concentration is obtained, proving Lowe right.

Anesthesia, Closed-Circuit↗
PubMed1987

[Propofol and thoracic surgery].

20 patients undergoing thoracic surgery were studied. Before anaesthesia either a catheter was placed in the intercostal space, at the same level as the thoracotomy (16 patients) or an epidural catheter was inserted if there was a contraindication of intercostal blockade (4 patients). Marcaine 0.5--was injected. Anaesthesia was induced with propofol 2.5 mg.kg-1, vecuronium 0.1 mg.kg-1, dextromoramide 50 mcg.kg-1. It was maintained with propofol 9 mg.kg-1.h-1 for 30 mn, then 4.5 mg.kg-1.h-1 for following hours (by a syringe pump) and vecuronium 0.1 mg.kg-1.h-1. Cardio vascular effects were studied only in the 16 patients with intercostal blockade: during induction bradycardia in 3 patients, and systolic arterial pressure (S.A.P.) decrease of 30% in 8 patients were observed. After the incision, heart rate and S.A.P. became steady. The average duration of anaesthesia was 214 min +/- 74. The time from the end of propofol infusion to the moment of extubation was 15.4 min +/- 33 and the time to recover all mental faculties was 46 mn +/- 11. 30 min after the end of anaesthesia the maxima minute ventilation was equal to the post operative value at 48 H. Propofol anaesthesia allows a fast awakening, without cumulative effects.

Anesthesia Recovery Period↗
PubMed1986

[Action of ifenprodil tartrate in obliterative arteriopathies of the lower limbs. Combined studies using proximal blood flow and distal transcutaneous oxygen pressure].

A simultaneous analysis of both the variations of the flow in the stenosis artery and the distal PO2, was carried out during an injection of an alpha-blocker: the Tartrate d'Ifenprodil, on twenty-five patients afflicted with occlusive disease of the lower limbs requiring surgery. The measurements were taken under general anaesthesia, before any surgical operation, the hemodynamic and ventilatory balance being monitored by radial manometry and arterial gas analysis. We observe an increase of proximal arterial flow and at the same time an improvement of the distal TcPO2. Moreover, the variations of microcirculation flow measured by TcPO2 are correlated with proximal flow variations, this relation: delta TcPO2 = K delta Q + A is more true in the first and the second stages of Fontaine. With the same (Tartrate d'Ifenprodil) posology, the distal benefit measured by transcutaneous oximetry is less important in advanced stages compared with other stages (everything else being equal). The transcutaneous measurement of the distal oxygen pressure, allows an objective view of microcirculatory improvement obtained by a vasoactive substance (ifenprodil tartrate) considering the specific nature of each patient arteriopathy.

Adult↗