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Biomedical subjects

J Chalon

Publications and source records attributed to J Chalon.

At least 37 records · Page 2Linked to original sources
PubMed1981

Routine cytodiagnosis of pulmonary malignancies.

Anesthesiologists normally discard the material routinely suctioned from the tracheal tube of patients under general endotracheal anesthesia. We preserved, and later examined microscopically, specimens from 10,621 patients. We found 11 cytologically abnormal smears from subjects with unsuspected pulmonary involvement, an incidence slightly more than 1:1,000. The accuracy of our method was assessed by calculation of the percent of abnormal smears obtained from patients with prediagnosed bronchogenic carcinomas: 40% when suctioned material was immediately spread on slides, and 67% when cellular concentration was achieved by mucolysis followed by filtration or centrifugation. Secretions normally discarded can reveal much information that would otherwise be missed. Our method may be useful if applied to patients at risk (heavy smokers, workers with asbestos, nitrosamine, or benzopyrine, miners of radioactive material, etc) who undergo general anesthesia for incidental surgery.

Adolescent↗
PubMed1981

Exposure to halothane and enflurane affects learning function of murine progeny.

This study was conducted to assess the learning function of murine progeny born of mothers that had received either 1% or 2% halothane or 2% or 4% enflurane, on days 6 and 10 or days 14 and 17 or gestation. Their timed performance at the age of 6 to 7 weeks was compared in a maze with that of control mice of similar ages that had not been exposed to anesthetics prenatally. All mice exposed to halothane in utero performed poorly at first, especially the group with mothers exposed to 2% halothane on days 14 and 17 of pregnancy. By the 10th training period, the performance of all mice improved but remained significantly slower than control mice. The offsprings of mice exposed to enflurane also performed poorly on the first training period, but between the fifth and seventh training periods, made statistically significant progress. However, they too remained slower in maze performance than control mice. Although blood pressure and arterial blood gas studies were only performed on two pregnant mice, data obtained suggest that the anesthetics did not have sufficient effect on respiration to affect our results. Second generation offspring, born to dams exposed to 2% halothane in utero late in pregnancy and sired by normal unexposed males, were also consistently slower than control mice, indicating a possible genetic effect induced by the anesthetic.

Animals↗
PubMed1980

A microprocessor computer program. An aid to the International System of Units.

The transition from the scientific system of measurements used in the United States to the Système International creates difficulties for Americans who consult European or Canadian journals. Similar difficulties occur when they want to publish abroad. We have developed a program for the portable microcalculator, which may be coupled selectively to a recorder. Two types of programs are used on 7.5 X 1.5-cm electromagnetic cards. Program P1 is used with the recorder and program P2 with the calculator only.

Abbreviations as Topic↗
PubMed1980

Considerations on impedance cardiography.

Impedance cardiography is an electronic plethysmographic technique which provides information on cardiac stroke index, myocardial performance, thoracic fluid content and peripheral circulation. The method has gained popularity in recent years because it is not invasive. While less precise in absolute terms than invasive methods the results are reproducible, and the technique accurately assesses variations in measurements. It may be used in most anaesthetized patients without the possibility of any of the complications which sometime accompany the use of more precise invasive methods. This paper describes impedance cardiography and methods for its use.

Cardiography, Impedance↗
PubMed1980

Effects of minute volume increases on the rebreathing characteristics of the Bain anaesthesia circuit during controlled ventilation.

In the course of a study on the carbon dioxide rebreathing characteristics of the Bain anaesthesia circuit, it was noted that raising the minute volume without changing the fresh gas inflow invariably led to increased rebreathing of expired gases. Altering tidal volume and rate in order to reproduce a given minute volume had the same effect on rebreathing. A nomogram constructed to quantitate increases in rebreathing in function of carbon dioxide production per minute, fresh gas flow from the anaesthesia machine, and minute volume is produced. It can be used to assess the amount of fresh gas flow necessary to mantain a steady and inspired gas composition.

Anesthesiology↗
PubMed1980

Bronchofiberscopic jet ventilation.

The suction-biopsy channel of a flexible bronchofiberscope was used to provide subglottic jet ventilation in six dogs and eight adult human subjects. In dogs, after 75 minutes of ventilation at a driving pressure of 2580 torr/cm2 (50 lb/in2) the PaO2 was 412 +/- 18 torr and the PaCO2 32 +/- 3 torr with a peak airway pressure of 6 torr. In patients, after 30 minutes of jet ventilation, the PaO2 varied from 347 to 480 torr, the PaCO2 from 17 to 36 torr, and peak tracheal pressure from 6 to 8 torr. The method is convenient, simple and applicable in a variety of clinical situations.

Adult↗
PubMed1980

Tracheobronchial cytologic changes during prolonged cannulation.

The tracheobronchial cytology of eighteen patients undergoing prolonged mechanical ventilation were examined for the type of cell population present, together with the morphologic integrity of the ciliated epithelial cells 1, 3, 5,10, and 20 days after tracheal cannulation. Smears obtained from patients recovering from cardiac surgery were different from all others in that: (1) they contained fewer epithelial cells (ciliated and squamous) which disappeared earlier; (2) they initially had more pus cells which appeared earlier; (3) they originally contained more histocytes but these were not found after the 5th day after cannulation; and (4) their ciliated epithelial cells displayed more cytomorphologic changes. Differences in cytology were attributed to impaired cardiac output in these patients. The reduced perfusion pressure of the vasculature of their tracheobronchial tree was presumably unable to sustain the lateral wall pressure of tube cuffs pressure, which further impaired tracheal perfusion. Less reparative processes (squamous metaplasia and early appearance of histiocytes) were also found in patients following cardiac surgery, together with early invasion of smears by pus cells indicating premature lowered resistance to bacterial infection.

Adolescent↗
PubMed1979

Humidity and the anesthetized patient.

Damage to the ciliated cells of the tracheobronchial tree and incidence of postoperative pulmonary complications were measured by point-scoring systems in 202 patients who breathed dry and humidified anesthetic gases for 225 +/- 78 min. The incidence of postoperative pulmonary complications decreased as the humidity of administered anesthetic gases increased from 0 to 32.5 mg H2O/l. A similar relationship was found between the amount of inhaled moisture and the damage to the ciliated epithelium of the tracheobronchial tree. These results appear to indicate that a high inspired humidity is beneficial for operations on normothermic patients, and that cellular damage caused by dryness is a possible contributory factor in the production of the pulmonary atelectasis that follows stoppage of the mucociliary transport system in the immmediate postoperative period.

Adolescent↗
PubMed1979

An improved program to calculate intrapulmonary shunting.

A computer program was developed to calculate intrapulmonary venous admixture on a Texas Instruments TI 59 programmable calculator. The program incorporates the following characteristics: 1) a correction for saturated water vapor pressure which varies with body temperature; 2) a mathematical model of the standard oxyhemoglobin dissociation curve; and 3) correction factors for shifts of the dissociation curve due to variations in pH and carbon dioxide tension. It also corrects oxygen tensions obtained at electrode temperature to those at patient temperature, and calculates variations of the Bunsen solubility coefficient of oxygen in blood with body temperature.

Bionics↗