Papers by Jean-Francois Bertholon
Tobacco Control, 2010
Contributors GW reviewed the literature, determined the methods, did the analysis and wrote up th... more Contributors GW reviewed the literature, determined the methods, did the analysis and wrote up the research letter.
Respiratory Care, 2011
BACKGROUND: A simple method for effective bronchodilator aerosol delivery while administering con... more BACKGROUND: A simple method for effective bronchodilator aerosol delivery while administering continuing continuous positive airway pressure (CPAP) would be useful in patients with severe bronchial obstruction. OBJECTIVE: To assess the effectiveness of bronchodilator aerosol delivery during CPAP generated by the Boussignac CPAP system and its optimal humidification system. METHODS: First we assessed the relationship between flow and pressure generated in the mask with the Boussignac CPAP system. Next we measured the inspired-gas humidity during CPAP, with several humidification strategies, in 9 healthy volunteers. We then measured the bronchodilator aerosol particle size during CPAP, with and without heat-and-moisture exchanger, in a bench study. Finally, in 7 patients with acute respiratory failure and airway obstruction, we measured work of breathing and gas exchange after a  2-agonist bronchodilator aerosol (terbutaline) delivered during CPAP or via standard nebulization. RESULTS: Optimal humidity was obtained only with the heat-and-moisture exchanger or heated humidifier. The heat-and-moisture exchanger had no influence on bronchodilator aerosol particle size. Work of breathing decreased similarly after bronchodilator via either standard nebulization or CPAP, but P aO 2 increased significantly only after CPAP aerosol delivery. CONCLUSIONS: CPAP bronchodilator delivery decreases the work of breathing as effectively as does standard nebulization, but produces a greater oxygenation improvement in patients with airway obstruction. To optimize airway humidification, a heat-and-moisture exchanger could be used with the Boussignac CPAP system, without modifying aerosol delivery.
Radiation Protection Dosimetry, 1999
ABSTRACT An accurate estimate of aerosol deposition in children as well as in adults is of specia... more ABSTRACT An accurate estimate of aerosol deposition in children as well as in adults is of special importance for dosimetry after inhalation of radionuclides. The breathing mode, oral, nasal or oronasal, influences total deposition and relative fractions of the inhaled aerosols that will deposit in the extrathoracic and thoracic airways. Human models of airway deposition rely on standard values based on experimental data. In the absence of specific information, the pattern of airflow partitioning between the two routes is assumed to be similar in adults and in children. In order to better assess breathing modes in healthy subjects of various ages, for who specific data are needed, the oronasal partitioning of ventilation during graded exercise was studied in 10 adults, aged 35 to 56 and 10 children, aged 8 to 16. During the test, oral and nasal flow rates were separately recorded, using a mouthpiece and a nasal mask. For all the subjects, the exercise test was symptom limited while for adults a safety limit was added to either cardiac frequency (CF > 160 min-1) or systolic blood pressure (SBP > 210 mm Hg or 28 kPa). Increments of power output were 25 W for adults and 10 W in children, each minute. It was observed that 6 adults out of 10 had a exclusively nasal ventilation at rest and switched abruptly to oronasal breathing during exercise when total ventilatory rate reached 38 to 65 1.min-1. Nine out of the 10 children already had oronasal ventilation at rest and merely increased their oral fraction from 20 to 84% of the total airflow at rest, up to 32 to 99% for the highest power output during the exercise test. The highest oral fractions were seen in the youngest children. The airflow partition between nose and mouth varied greatly among subjects, and this variability seems partly explained by airway resistances. From these results and from those of the relevant literature, the conclusion is that the ventilatory behaviour, both at rest and during exercise tends to be age-dependent. To assess the possible effects of these observations on the reliability of the radiological doses recommended by ICRP, deposition was calculated for 1 and 5 �m particles in adults and for 1 �m in children according to these data and compared with the model's defaults.
Intensive Care Medicine, 1998
Conclusion: These data, performed in vitro, should be assessed also by further clinical studies.
Respiration, 2013
in water) and a vaporization chamber, which produce an aerosol that simulates the smoke of a ciga... more in water) and a vaporization chamber, which produce an aerosol that simulates the smoke of a cigarette (fig. 1). Nicotine and other additives like flavorings and glycerol (purified vegetable glycerine) may be added in various concentrations to the liquid. No combustion is involved in the process and the 'smoke' produced is an aerosol of liquid particles, a 'mist' [1]. Advertised as a valid way to quit smoking real cigarettes, the e-cigarette has been the subject of much controversy but little experimental study. This review provides a brief overview of the current evidence on the ecigarette. Aerosol Generation Besides water, the main ingredient of the e-liquid is usually propylene glycol (PG) in water. A mechanical sensor detects when the user inhales and it then triggers the microchip controlling the heater which raises the temperature in the vaporization chamber. As specified by the manufacturers, the temperatures in the vaporization chamber range from 40 to 65 ° C [1]. Recently, however, variable voltage devices gained popularity as they can increase the temperature of operation and the heater surface area in order to tune the vapor to the user's satisfaction. No reliable data could be found on the range of temperatures in these recent devices. The same uncertainty exists about the operating temperature in
The Journal of antimicrobial chemotherapy, 2018
Nebulized colistimethate sodium (CMS) can be used to treat ventilator-associated pneumonia caused... more Nebulized colistimethate sodium (CMS) can be used to treat ventilator-associated pneumonia caused by MDR bacteria. The influence of the diluent volume of CMS on aerosol delivery has never been studied. The main objectives of the study were to compare aerosol particle characteristics and plasma and urine pharmacokinetics between two diluent volumes in patients treated with nebulized CMS. A crossover study was conducted in eight patients receiving nebulized CMS every 8 h. After inclusion, nebulization started with 4 million international units (MIU) of CMS diluted either in 6 mL (experimental dilution) or in 12 mL (recommended dilution) of normal saline in a random order. For each diluent volume, CMS aerosol particle sizes were measured and plasma and urine samples were collected every 2 h. Nebulization time and stability of colistin in normal saline were assessed. The mass median aerodynamic diameters were 1.4 ± 0.2 versus 0.9 ± 0.2 μm (P < 0.001) for 6 and 12 mL diluent volumes, ...
Radiation Protection Dosimetry
ABSTRACT Human models of airway deposition require standard values derived from experimental data... more ABSTRACT Human models of airway deposition require standard values derived from experimental data. An experimental device was designed to measure partitioning of airflow between nose and mouth in response to incrementally graded exercise on an ergometer bicycle. Oral and nasal flow rates were recorded separately by two Fleisch pneumotachographs; cardiac frequency and arterial blood pressure were also recorded. Posterior rhinomanometry and flow rates during maximal vital capacity manoeuvre were simultaneously measured. Airflow fractions by mouth breathing were dependent upon the total ventilation required: at the maximal work load completed by ten subjects, they ranged from 30 to 67%. In six of them, breathing became abruptly oronasal at ventilation levels from 38 to 65 l.min-1. In the other four, oral breathing was already considerable at rest; and it increased regularly towards maximal ventilation. In these subjects, the oral to nasal airflow ratios, measured by the flow-volume curve method, were higher than in the other six.
The objective of this paper is to address one of the primary reasons that manuscripts are rejecte... more The objective of this paper is to address one of the primary reasons that manuscripts are rejected for publication in the Journal of the International Association of Medical Science Educators (JIAMSE), poor manuscript writing. One of the primary goals of the International Association of Medical Science Educators (IAMSE) annual meeting is to improve the way we teach medical science students. The information that IAMSE members share in their poster presentations represents cutting-edge medical education research. The impact of these presentations is limited if the results are not disseminated beyond the annual IAMSE meeting to a larger audience. It remains a goal of the JIAMSE Editorial Board to encourage IAMSE members to share their medical education research with the community of medical educators by publishing the results of their work in JIAMSE. The journal is the peer-reviewed, biannual (June and December) electronic journal of IAMSE that is published in three languages (i.e., En...
Revue des maladies respiratoires, 2010
Second hand cigarette smoke consists predominantly of nanoparticles (with two dimensions less tha... more Second hand cigarette smoke consists predominantly of nanoparticles (with two dimensions less than 100 nanometres). The aim of this study was to examine the aerosol of cigarette smoke suspended in the air of a smoking room, its disappearance over the course of time, and its retention in the airways of passive smokers, as these processes remain poorly characterised. A smoking machine produced cigarette smoke in a room. A low pressure electrostatic impactor with 13 plates, measured the size distribution and the concentration of the smallest particle sizes in the room air. Healthy adult volunteers (n=14) inhaled and exhaled this air through a nasal mask, allowing calculation of the retention of nanometric particles. The tobacco smoke aerosol was composed of 75% of nanometric particles. The half-life of these particles in the air was 18min. After 2h, 3% of the tobacco smoke particles remained suspended in the air. In passive smokers, the measured airway retention was on average 20%. Thi...
Revue des maladies respiratoires, 2008
It is a popular perception that narghile (water pipe) smoking is less harmful to the lungs than c... more It is a popular perception that narghile (water pipe) smoking is less harmful to the lungs than cigarettes in both active and passive smokers. Using a sinusoidal pump we simulated water pipe smoking in conditions close to users' habits. The particle sizes and concentrations in the smoke streams were measured with an electrical low pressure impactor (ELPI), sorting particle numbers and size into 12 classes ranging from 0.028 to 10 microm in diameter. Water pipe smoke contains microparticles and nanoparticles. The main inhaled smoke stream (C1) contains particles in a concentration of 3.55 x 10(6) ml(-1) with a median particle diameter (D50) of 0.34microm before bubbling through water. After bubbling, it retains 1.20 x 10(6) ml(-1) particles with a D50 of 0.27 mm, indicating that 2/3 of the particles are retained in the water, the smallest being trapped the less. Compared with C1, the D50 of the side stream smoke (C2) is smaller (0.11mm) while the D50 of the expired stream (C3) is...
Revue des maladies respiratoires, 2007
For several decades a more peripheral distribution of the broncho-pulmonary pathologies related t... more For several decades a more peripheral distribution of the broncho-pulmonary pathologies related to tobacco has been observed. The aim of this study is to examine whether changes in the particle size of cigarette smoke as the result of new manufacturing technologies could play a part in the observed epidemiologic changes through a more distal disposition of smoke particles in the airways. Using a smoking machine and a low pressure electrostatic impactor we measured the particle size of the smoke from six different types of cigarette, representing old and new manufacturing techniques. The effect of a filter was assessed by a size analyser measuring the electrical mobility of the particles. The results show a difference in particle size between the primary smoke inhaled by the smoker, S1 (0.27 +/- 0.03 microm.) and the secondary smoke, S2 inhaled by passive smokers (0.09 +/- 0.01 microm). There is no difference in particle size between the 6 different types of cigarette. Filters dilute...
Annales d'oto-laryngologie et de chirurgie cervico faciale : bulletin de la Société d'oto-laryngologie des hôpitaux de Paris, 2001
Nebulization of solutions associating gomenol, dexamethasone and framycetin is very widespread in... more Nebulization of solutions associating gomenol, dexamethasone and framycetin is very widespread in otorhinolaryngology (particularly for the treatment of actue laryngitis and post-traumatic laryngitis and rhinitis and for the tracheotomy care). A rigorous clinical evaluation is however lacking. The aim of this work was to evaluate use of such solutions in comparison with the recommendations issuing from the National Session in April 1997 on good practices for aerosol therapeutics. Stability and granulometry were studied in order to optimize processing. A new formulation and new technical methods of administration are proposed in relation to the results of this study and the national recommendations.
Revue de pneumologie clinique, 1994
We measured with a laser velocimeter granulometric deposit of an aerosol anti-infectious agent, f... more We measured with a laser velocimeter granulometric deposit of an aerosol anti-infectious agent, fusafungin, administered with a controlled inhalator. Total drug deposit was determined on the basis of a granulometric spectrum of the polydispered aerosol (mass mean aerodynamic diameter (MMAD) = 2.8 +/- 1.7 microns) and dispersion in the airways was estimated using the Stahlhofen model. We first compared deposits obtained with oral inhalation in 19 normal subjects and 20 patients with chronic obstructive lung disease. Total deposit in the airways of patients with chronic obstructive lung disease (82%) was not significantly different from that in normal subjects (85%). Estimated dispersion in normal airways was 27% in the alveoles, 8.4% in the tracheobronchic region and 23.5% in the extrathoracic regions. We then compared deposits after nasal inhalation in 22 normal subjects and 21 patients with rhinitis: nasal deposit was significantly greater in patients with rhinitis (54.5%) than in ...
Journal de physiologie
The arterial pulse wave velocity is determined to a large extent by the arterial elastic modulus.... more The arterial pulse wave velocity is determined to a large extent by the arterial elastic modulus. We tried to assess the importance of this parameter in cardio-vascular adaptation to exercise by measuring pulse wave velocity (c) in 45 sedentary subjects and 28 competitive cyclists whose ages ranged from 14 to 47 years. The measurements were performed at rest and during the recovery phase after ergometric exercise. At constant diastolic pressure, a positive linear relationship was demonstrated between c and age in both the sedentary and trained subjects. The slope of this relation was significantly different in the two groups. During the recovery phase, at constant diastolic pressure, a linear relationship was also established between c and the relative increase in systolic pressure in the sedentary group classified into six age subgroups. The slope of this relation increased with age. The part taken by diastolic flow velocity during exercise in the increase in c was demonstrated in ...
Biomedicine & pharmacotherapy = Biomédecine & pharmacothérapie, 1982
Journal of applied physiology (Bethesda, Md. : 1985), 1986
We have tested the hypothesis that there is a positive relation between arterial elasticity and p... more We have tested the hypothesis that there is a positive relation between arterial elasticity and physical working capacity (PWC) at a given age. The subjects were 28 young men, 16-18 yr old. Arterial elasticity was evaluated by measuring the carotid to femoral pulse-wave velocity (c) at rest. The slope, S(c) of the relation between c and the diastolic blood pressure was studied during a cold pressor test to test vascular reactivity. The relationship between heart rate (HR) and work load was determined using a cycle ergometer; the variables measured were the slope of this relation S(PWC) and the power output at a HR of 170 min-1 (PWC170). The PWC170 ranged from 1.8 to 4.6 W/kg, and values of c ranged from 3.9 to 6.8 m/s. A strong inverse linear relation was found between c and PWC170 (r = -0.76), whereas the HR at rest was positively related to both c (r = 0.68) and PWC170 (r = 0.74). There was no relationship between HR at rest and the slopes S(c) and S(PWC); the latter two variables...
Revue des Maladies Respiratoires, 2013
par le fumeur dans son environnement, le D50 était de 0,34 m et 0,29 m avec et sans nicotine. La ... more par le fumeur dans son environnement, le D50 était de 0,34 m et 0,29 m avec et sans nicotine. La demi-vie dans l'air du courant principal C1 était de 11 secondes car il disparaît en s'évaporant rapidement passant sous forme gazeuse. Par comparaison avec les cigarettes ordinaires et la chicha qui produisent un aérosol dont les particules ont une demi-vie de 19 à 20 minutes, il ne présente pas de risque réel de « tabagisme passif ».
The Journal of Physiology, 1988
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Papers by Jean-Francois Bertholon