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Biomedical subjects

B Hannhart

Publications and source records attributed to B Hannhart.

At least 19 recordsLinked to original sources
PubMed2005

Witnessed breathing pauses during sleep: a study in middle-aged French males.

The aim of the study was to evaluate the prevalence, the covariates and determinants of respiratory pauses during sleep in a sample of French middle-aged males. Study subjects were 850 active males, aged 22-66 years; 88.4% of them answered the question on breathing pauses during sleep from a structured, validated sleep questionnaire. Forty-one (=5.4%) subjects reported breathing pauses at least once a week; these "positive responders" were older, heavier and had larger neck- and waist girths as compared to subjects with negative answers. Loud habitual snoring, various sleep disturbances, excessive daytime sleepiness, a doctor diagnosis of sleep apnoea, history of stroke and hypertension were significantly more frequent among subjects with breathing pauses during sleep. The prevalence found in this survey was close to that reported from the UK (5.2%). However, by logistic regression, we identified novel determinants of breathing pauses i.e. habitual snoring, loud snoring, and excessive sleepiness, factors well known in clinical setting, but never previously reported in epidemiologic studies.

Adult↗
PubMed2004

Marital status and sleep-disordered breathing in a sample of middle-aged French men.

The aim of the present study was to test the hypothesis that unmarried (single) men have more sleep-disordered breathing symptoms due to a higher prevalence of obesity and a less healthy lifestyle than men living with a partner. Men (499) aged 23-66 years completed a structured questionnaire, had standard anthropometric measurements and a simple, noninvasive nose-throat examination. Of the 499,496 subjects answered the question concerning their marital status; 86% of them were married or lived with a partner (reference group) and the other 14% had never been married, divorced, or widowed ("single" group, considered at risk). Single subjects were younger, included slightly more smokers (30 vs. 23%) and more subjects with a history of chronic bronchitis, and less frequently had a large soft palate. The prevalence of sleep-disordered symptoms was not significantly different between the two groups. However, a study involving a larger number of subjects with information regarding alcoholic consumption may be needed to further evaluate this question.

Adult↗
PubMed2001

Occupational status and sleep-disordered breathing in a sample of French males.

Sleep-disordered breathing (SDB) and lower socio-professional status have in common a series of risk factors for ill health such as sedentary lifestyle, weight excess, heavy alcohol and tobacco consumption. We hypothesised that SDB will be more prevalent in lower socio-professional groups. A total of 496 male middle aged subjects (23-66 years) were tested with a protocol including a self-completed structured sleep questionnaire (translation of the Madison sleep cohort study form), anthropometry (including neck, waist and hip girth) and a simple, non-invasive nose-throat examination by a specialist physician. The subjects were classified according to the 10 major groups of the ISCO-88 classification (International Labour Office). Our sampling base did not contain subjects in the major groups 1 (senior officials, legislators), 6 (fishery and agricultural workers), and zero (armed forces), thus these groups were not represented in the analysis. To improve the power of the statistical analysis, groups 3 and 4, 5 and 7, 8 and 9 were merged, the analysis thus including four categories. The differences in demographic data were negligible; as expected, smoking was more prevalent in low socio-occupational groups (difference non-significant). A history of chronic bronchitis was more frequent in low socio-occupational groups, while a low physical job labour was more frequent in higher occupational groups. We did not find any differences in the prevalence of sleep-related respiratory disturbances (snoring, sleep apnoeas). This first study of the possible association between socio-occupational factors and sleep disordered breathing was negative, but we believe further studies, on larger samples, with a more homogeneous distribution of social groups are warranted.

Adult↗
PubMed2001

Breathing pauses during sleep: can a non-invasive ENT examination help identify subjects at risk in epidemiological settings?

In patients with obstructive sleep apnoea (OSA) anatomic and functional upper airway abnormalities are frequent and severe. Invasive methods are used to identify and quantitate the obstruction, to precisely locate its site, etc. as part of pre-treatment or of preoperative evaluations.These methods (lateral skull radiographs, computerized tomography, MRI, fibroscopies, etc) are too expensive and too invasive to be utilized in field surveys. To the classical sleep questionnaires and anthropometric measurements, some simple nose-throat examinations, easily accepted by the volunteers in a population study, could add useful information for the identification of the subjects at risk for sleep-disordered breathing. The present paper is a review of these examinations and of their utility.

Humans↗
PubMed2001

Prevalence of habitual snoring in a sample of French males. Role of "minor" nose-throat abnormalities.

BACKGROUND: No data on snoring prevalence obtained with a standard questionnaire exist for France. Major nose-throat abnormalities have been demonstrated in cases with obstructive sleep apnea; evidence of "minor" abnormalities in community studies is scarce. OBJECTIVES: The first objective of our study was to estimate the prevalence of habitual snoring in a sample of middle-aged active males in France. The second objective was to test the hypothesis that "minor" nose-throat abnormalities could be associated with habitual snoring in a field survey. METHODS: Three hundred thirty-four male employees of a local university volunteered for the study (93.6% of those contacted by mail); 300 returned a sleep questionnaire. The protocol also included anthropometry and a noninvasive nose-throat examination. RESULTS: Complete data were obtained in 299 subjects aged 23-63 years. When "habitual snorers" (= 32%) were compared with never-snorers, significant differences were found for all anthropometric variables, except height. In univariate analysis, habitual snoring was associated with a large number of variables, including a large soft palate, a large uvula, and altered nose patency. A logistic regression model retained 8 factors independently associated with snoring: age, neck circumference, tobacco consumption, breathing pauses during sleep, not feeling rested during the day, need for coffee to stay awake, blocked or running nose at night and a large soft palate. CONCLUSIONS: The prevalence of habitual snoring in this sample of middle-aged French males was 32%. We confirmed the significant association of habitual snoring with age, weight excess, and tobacco smoking, and identified two further factors: blocked nose at night and a large soft palate.

Adolescent↗
PubMed2000

Corticospinal pathway and exercise hyperpnea: lessons from a patient with Arnold Chiari malformation.

The study of a patient with an Arnold Chiari malformation gave us the opportunity to test the hypothesis that the motor cortex contributes significantly to respiratory control during muscular exercise through the corticospinal pathway. The patient was a 25 years old woman who exhibited a severe impairment of the 'automatic' ventilatory control due to a type I Arnold Chiari malformation. Since she never complained of being breathlessness even on exertion, the breath-by-breath ventilatory (VE) and pulmonary gas exchange responses to a three minute bout of constant work rate exercise at 60 W, 90 W and 120 W were studied before then 16 and 23 months after posterior fossa decompression. The VE response to the three different levels of exercise was dramatically blunted so that the expected vertical relationship between PET(CO(2)) and VE during moderate exercise was replaced by an almost horizontal relationship with a slope ranging from 0.15 to 0.17 l/min/Torr. The reduced VE response was associated with a total lack of respiratory sensation during and following the exercise bouts. This abnormal ventilatory response to exercise persisted despite posterior fossa decompression. There was however no evidence of an alteration of the corticospinal pathway. Indeed, not only was there no sign of motor deficit but the patient was able both to mobilize 96% of her expected vital capacity and to voluntarily increase her ventilation to the level expected in a normal subject during exercise. This observation suggests that during exercise, motor control of respiratory muscles via a direct corticospinal pathway does not play a major role in adjusting phrenic motoneuron activity to the magnitude of the motor inputs to the exercising skeletal muscles.

Adult↗
PubMed1999

Validity of transcutaneous oxygen/carbon dioxide pressure measurement in the monitoring of mechanical ventilation in stable chronic respiratory failure.

The accuracy and precision of transcutaneous pressure measurements of oxygen (Ptc,O2) and carbon dioxide (Ptc,CO2) in the monitoring of nocturnal assisted ventilation in adult patients were evaluated. Transcutaneous measurements obtained with two analysers, Radiometer TINATCM3 (R) and Kontron MicroGas-7650 (K), were compared with arterial blood gases analysed in blood samples withdrawn simultaneously in 10 patients. Sensors were heated to 43 degrees C. Measurements of transcutaneous blood gases and arterial blood gases were collected six times at 1-h intervals. The data obtained with both instruments were similar and did not significantly change over the 5 h test period. Measurement of Ptc,O2 underestimated arterial oxygen tension (Pa,O2) and this underestimation increased with the level of Pa,O2 (p<0.01). Measurements of Ptc,CO2 overestimated arterial carbon dioxide tension (Pa,CO2) and this overestimation increased with the level of Pa,CO2 (p<0.05). These errors suggested an instrumental bias. Mathematical correction of this bias neutralized the error in accuracy and improved the precision (SD of the differences transcutaneous blood gases - arterial blood gases). An additional correction, suppressing the between-subject scattering, improved the actual precision: precision was reduced from 1.9 to 0.8 kPa (14.4 to 5.7 mmHg) (R) and from 1.7 to 0.5 kPa (13.1 to 3.7 mmHg) (K) for oxygen, and from 1.0 kPa (7.8 mmHg) (R) and 0.7 kPa (5.6 mmHg) (K) to 0.4 kPa (3.2 mmHg) for carbon dioxide (R and K). In conclusion, with these two successive corrections, transcutaneous oxygen and carbon dioxide provide a reliable estimation of blood gases to monitor nocturnal ventilation in adults with chronic respiratory failure.

Blood Gas Monitoring, Transcutaneous↗
PubMed1994

Comparative effects of laryngeal mask and tracheal tube on total respiratory resistance in anaesthetised patients.

We compared the effects of the laryngeal mask and tracheal tube on total respiratory resistance in 10 anaesthetised, mechanically ventilated patients undergoing otological microsurgery. The subjects were randomly divided into two groups. In the first group, the tracheal tube (Rüsch) was inserted for the first series of measurements. This was then replaced by a laryngeal mask (Intavent) and a second series of measurements was made during the first hour of operation. In the second group, the same protocol was applied with inverse order in the use of the devices. From the measurement of respiratory flow and pressure at the airway opening, total respiratory resistance was calculated by multiple linear regression. The data were corrected to eliminate the previously determined nonlinear resistance of the two devices. Arterial blood pressure, electrocardiogram, oxygen saturation and end-tidal carbon dioxide concentration were continuously monitored. With the laryngeal mask and the tracheal tube, mean (SE) minute ventilation was 9.4(0.9)l.min-1 and 8.1(0.9)l.min-1, respectively for end-tidal carbon dioxide concentrations between 3.6 and 4.1%. Although the glottic resistance was included in the measurement performed with the laryngeal mask but not with the tracheal tube, mean (SE) total respiratory resistance was not significantly different with the two devices (0.61(0.32) and 0.69(0.35) kPa.l-1.s, respectively). Leakage was avoided with the laryngeal mask because the insufflation pressure never exceeded 1.7 kPa except in one patient suffering from severe chronic obstructive pulmonary disease who had a total respiratory resistance of 1.45 kPa.l-1.s. During the first hour of the operation all respiratory variables remained stable irrespective of the device used.

Adult↗
PubMed1994

Effects of haemorrhagic hypotension on carotid chemosensory discharge in the kitten.

Hypotension is known to affect the rate of carotid chemosensory activity in the adult cat, but the relationship between arterial blood pressure and carotid sinus nerve discharge has not been established in the kitten. The purpose of this study was to determine the response of carotid chemosensory afferents to hypotension induced in normoxia and in hyperoxia in eight kittens aged 1 to 25 days. Hypotension was obtained by a gradual decrease in blood volume. The activity of a few chemosensory fibres was recorded from one carotid sinus nerve. Baseline steady-state mean arterial blood pressure and carotid chemosensory activity were, respectively, 70.0 +/- 4.3 mmHg and 7.6 +/- 1.9 impulse/s (mean +/- SEM) in normoxia and 56.3 +/- 6.7 mmHg and 0.58 +/- 0.2 impulse/s in hyperoxia. Lowering arterial blood pressure below 37.5 +/- 3.5 mmHg in normoxia and 26.8 +/- 2.3 mmHg in hyperoxia was associated with a consistent increase in the rate of chemosensory discharge. Above this threshold, blood pressure variations had little effect on carotid chemoreceptor activity. These data are qualitatively similar to those of adult cats and provide evidence that, in newborn kittens, changes in arterial blood pressure will not influence carotid chemosensory discharge unless these changes are out of the physiological range.

Action Potentials↗
PubMed1994

Effect of dopamine on carotid chemoreceptor activity in newborn kittens.

In newborn kittens, intravenous bolus injections of dopamine may be inhibitory or excitatory to the carotid chemosensory activity. In order to further identify the role of dopaminergic mechanisms on the chemosensory activity in the kitten, 10 anesthetized, paralyzed and artificially ventilated kittens aged from 1 to 21 days were studied. The activity of a few chemoafferent fibers from one carotid sinus nerve was recorded at three levels of FiO2 in N2, 21, 8 and 100%, before and during a continuous dopamine infusion at a dose of 10 micrograms/kg/min. The immediate effect of dopamine usually was a transient inhibition of carotid chemosensory discharge. After 2 min of infusion, the activity had consistently increased from 4.5 +/- 0.8 to 8.8 +/- 1.4 impulses/s (mean +/- SEM, p < 0.05) in normoxia. Dopamine also significantly increased the steady state chemosensory response to hypoxia from 24.6 +/- 3.7 to 33.4 +/- 5.3 impulses/s. Hence, continuous infusion of dopamine has a dual effect on carotid chemoreceptor activity: early inhibition followed by excitation. The excitatory effect enhances the response to hypoxia. These data suggest that the dual effect of dopamine on carotid chemosensory discharge may be related to dopamine concentration in the carotid body.

Action Potentials↗
PubMed1994

Effects of testosterone on hypoxic ventilatory and carotid body neural responsiveness.

Hypoxic (HVR) and hypercapnic ventilatory responses (HCVR) are known to be influenced by the administration of testosterone, but whether the hormone acts centrally or peripherally is unknown. To determine whether testosterone alters HVR, HCVR, and carotid sinus nerve (CSN) responsiveness to hypoxia, we compared the ventilatory and CSN responses of neutered male cats treated with testosterone with those of placebo-treated cats. Testosterone treatment increased resting ventilation and CO2 production but did not change end-tidal or arterial PCO2, implying that alveolar ventilation per unit CO2 production was unaltered. Testosterone treatment raised the HVR shape parameter A value 63% in the awake animals (from 16.9 +/- 4.2 to 28 +/- 4, p < 0.05) and 69% in the anesthetized cats (from 22.4 +/- 0.9 to 37.8 +/- 3.7, p < 0.05). Testosterone also augmented the HCVR slope S in awake cats (from 0.17 +/- 0.02 to 0.25 +/- 0.04, p < 0.05). Placebo treatment did not change HVR or HCVR. The CSN response to hypoxia was greater in the testosterone-treated than in the placebo-treated animals (A = 53.6 +/- 7.1 versus 27.1 +/- 5.5 respectively, p < 0.05). The crossplot of the simultaneously measured CSN activity and ventilation during progressive hypoxia showed that the central nervous system translation of CSN output into ventilation was similar in the hormone- and placebo-treated groups. Unilateral, proximal sectioning of the CSN decreased the ventilatory and the CSN responses to hypoxia in the testosterone-treated animals but not in the placebo group. These results indicated that testosterone increased hypoxic and hypercapnic ventilatory responsiveness and increased hypoxic sensitivity of the carotid body.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

[Radioimmunoassay of urinary cotinine: variability of measurements, identification of exposed subjects].

Urinary cotinine was assessed by a radioimmune assay (RIA) in a random subsample of 63 (out of 285) children aged 5 to 6 from 10 kindergartens in Nancy (N-E France). The result was adjusted for urine concentration by expressing cotinine per mg creatinine. The correlation between two successive determinations was excellent (r = 0.989) and the difference between the two mean values was minimal and non-significant (121.4 +/- 25.9 vs 121.0 +/- 25.0). Expressed in percentage of their mean, the difference between two determinations was on average 8.2%. The urinary cotinine determinations allowed a satisfactory separation of children exposed vs unexposed to parental tobacco smoke.

Child↗
PubMed1993

Effects of dopamine on the carotid chemosensory response to hypoxia in newborn kittens.

In a previous study, it has been shown that bolus injections of dopamine could either stimulate or inhibit the carotid chemosensory discharge in the kitten (Marchal et al., 1992a). To further characterize dopaminergic mechanisms in the carotid body during development, the effects of a continuous infusion of dopamine on carotid chemosensory activity in air, hypoxia (8% O2 in N2) and hyperoxia (100% O2) were studied in ten anesthetized, paralyzed and artificially ventilated kittens, aged 1 to 21 days and in three adult cats. One carotid sinus nerve was prepared for recording the activity of a single or a few chemosensory afferents. In the kittens, the immediate effect of dopamine at the onset of infusion (10 micrograms/kg/min) was an inhibition of the discharge in five kittens, a progressive excitation in four and no change in one. Four minutes after the onset of dopamine infusion, there was a significant increase in chemosensory activity both in room air (from 4.5 +/- 0.8 impulse/sec to 8.8 +/- 1.4 impulse/sec, mean +/- SEM, P < 0.05) and in hypoxia (from 24.6 +/- 3.7 impulse/sec to 33.4 +/- 5.3 impulse/sec, P < 0.05) but not in hyperoxia (0.5 +/- 0.2 impulse/sec vs 0.7 +/- 0.3 impulse/sec). The adult cats received four successive dopamine infusions at the rate of 2.5, 5, 7.5 and 10 micrograms/kg/min, in an attempt to establish a dose-response relationship. The effects of dopamine infusions were consistent within, but variable between, cats. The onset of dopamine infusion was associated with an inhibition of the discharge in two cats, at all infusion rates. In one of them, chemosensory activity returned quickly to control and the response to hypoxia was enhanced. In the other cat, the inhibition of the discharge persisted for the duration of the infusion, and the response to hypoxia was inhibited. In the third cat, dopamine had no effect on the chemosensory discharge. The patterns of chemosensory responses evoked by dopamine are qualitatively similar in kittens and cats, but the excitatory type of response appear to be more readily elicited in the kitten.

Action Potentials↗
PubMed1993

[Comparison of bronchodilator effects and site of action of fenoterol and ipratropium in chronic obstructive bronchitis].

There is no lack of data in the literature reporting on the efficacy of different bronchodilators. However, the discussion concerning the superiority of one bronchodilator over another in patients with chronic bronchitis and airflow obstruction is, and remains, a controversial subject. This has been particularly so since the perfection of synthetic anticholinergics delivered by inhalation without any side-effects. The aim of the present work is to compare the bronchodilator effects of a sympathomimetic, fenoterol (Berotec), and of an anticholinergic, ipratropium bromide (Atrovent), compared to a placebo in twelve unselected chronic bronchitics who had airflow obstruction and were in a stable clinical state. The bronchodilator effect of the two drugs was judged at the same time by variations on forced expired volume (FEV1) which was taken as a reference value, and of the maximum mid-expiratory flow (MEF) measured by spirography and also the variations of pulmonary resistance (delta Rrs) measured by the forced oscillatory method. The comparison of these indices enables the site of action of these agents to be specified. The dose response curve and the duration of action over six hours was assessed for each of the three agents. These were administered in succession and at random over three days by inhalation using an inhalation chamber. All the patients who were included were capable of producing a bronchodilator response but two of them responded only to one agent. The change in the FEV1 was comparable with the two active products. The change in MEF (an index of peripheral airways) was significantly greater following ipratropium.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Inhalation↗