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Biomedical subjects

A Neidhardt

Publications and source records attributed to A Neidhardt.

16 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↗
PubMed1976

[Prevention of tracheal lesions by rhythmic insufflation of the intubation catheter ballone].

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.

Humans↗
PubMedDate not supplied

Effect of cytidine diphosphate choline on anoxia tolerance of cultured myocardial cells.

Three series of cultured Wistar rat heart cells (10 treated and 10 controls x 3) were examined with a laser contraction-meter in a special chamber for anoxia to determine whether cytidine diphosphate choline (CDPC), a membrane phospholipid precursor, can protect against total oxygen deprivation. Heart rate and force of contraction (inotropism) were monitored during a 40-minute period of hypoxia. CDPC in a concentration of 142 micrograms/ml-1 was added to the culture medium only during the anoxia period in series I, during the 3 days of culture in series II, and during the 3 days of culture and the 40-minute hypoxia period in series III. In series I, inotropism decreased by 21% versus 55% in control group (P less than 0.05). In series II, inotropism decreased by 25% versus 43% in control group (P less than 0.05). In series III, inotropism decreased by 22% versus 44% in control group (P less than 0.05). Compared with control cells, cells treated with CDPC during anoxia maintained a significantly greater inotropic state. The effect is greatest if the cells are weak, as in series I. CDPC may be a useful component of the cardioplegic mixture during cardiopulmonary bypass and in the treatment of myocardial ischemia.

Animals↗
PubMedDate not supplied

[Supra-umbilical laparotomies and perturbed pulmonary blood oxygenation (author's transl)].

Pulmonary blood flow and ventilation were studied in twenty three patients after supra-umbilical laparotomy by means of samplings of blood gases and expiratory air content, spirometry, and pneumotachography. Although ventilatory perturbations predominate (notably, a lessened tidal volume and an amputation of the residual functional capacity they are found in conjunction with perfusion anomalies, an shown by the study of O2 and CO2 ductances). The PCO2/PO2 diagram of Rahn and Fenn further illustrates these perfusion alterations; in addition, it gives an impression of the metabolic orientation of the patients in the early post-operative period. Several physiopathological notions are derived from the study, as well as some therapeutic proposals.

Adult↗