Evidence for expiratory flow limitation of extrathoracic origin in patients with obstructive sleep apnoea.

Background: A study was undertaken to examine the expiratory flow response to a negative pressure (NEP) applied at the airway in patients with no abnormalities of the intrathoracic airway but suffering from the obstructive sleep apnoea syndrome (OSAS).

Methods: Nineteen patients with OSAS with normal spirometric values were studied. NEP of -5 cm H(2)O and -10 cm H(2)O was applied to the mouth when sitting and when supine.

Heart rate variation after breath hold diving with different underwater swimming velocities.

Background: The aim of this study was to demonstrate the kinetics of heart rate and blood lactate level obtained after repeated short breath holds with muscular effort in a swimming pool.

Experimental Design: each subject had to perform a series of breath hold diving at rest and three series for different underwater swimming velocities. A series corresponded to six dives of a 30 sec duration separated by a recovery period of 30 sec.

Ventilatory responses to hypercapnia in divers and non-divers: effects of posture and immersion.

The aim of this study was to determine the effects on respiratory drive of two factors, one mechanical (lung volume) and one chemical (sensitivity to hypercapnia), that are involved in determining the breath-hold duration (BHD). Functional residual capacity was measured by helium dilution with the subject seated in air, seated in water and in the prone position in water. Hyperoxic hypercapnia rebreathing (Read's method) was carried out under identical environmental conditions to assess the effects of CO2 pressure on respiratory centre output by measuring ventilation, mean inspiratory flow and occlusion pressure.

Comparison between anatomy and resistance of upper airway in normal subjects, snorers and OSAS patients.

Upper airway (UA) anatomical abnormalities are frequently observed in obstructive sleep apnea syndrome (OSAS). The correspondence between UA anatomical modifications and UA resistance (UAR) had not been studied. We aimed to determine if cephalometric characteristics could be related to segmental UAR.

Prevalence of daytime hypercapnia or hypoxia in patients with OSAS and normal lung function.

The purpose of this study was to determine factors increasing daytime PaCO2 or PaO2 in obstructive sleep apnoea syndrome patients (OSAS) with normal pulmonary function tests. Anthropometric, pulmonary function tests, arterial blood gases and sleep polygraphic data were analysed retrospectively in 218 OSAS patients (apnoea-hypopnoea index > 15 h(-1); 18 females, 55 +/- 11 years): 125 patients had abnormal pulmonary function tests, i.e.

Breath-holding time: effects of non-chemical factors in divers and non-divers.

Two main factors (chemical and non-chemical factors) are involved in the determination of breath-holding time (BHT). Earlier studies have shown that chemical factors can be modified by training. The aim of this study was to establish whether BHT can be lengthened or shortened by changes in non-chemical factors according to the degree of training of the divers.

Upper airway resistance during progressive hypercapnia and progressive hypoxia in normal awake subjects.

Ventilatory motor output is known to influence the upper airway. Although inspiratory upper airway resistance decreases during progressive hypoxia or hypercapnia, the effects of hypoxia and hypercapnia on expiratory upper airway resistance remain unknown. In the present study, we attempted to examine whether the expiratory and the inspiratory upper airway resistances were modified in the same way by progressive hyperoxic hypercapnia or by progressive normocapnic hypoxia.

Effects of pressure ramp slope values on the work of breathing during pressure support ventilation in restrictive patients.

Objective: To investigate, in restrictive patients, the influence of pressure ramp slope values on the efficacy of pressure support ventilation.

Design: Prospective study.

Setting: A university hospital medical intensive care unit.

Transvenous versus perinervous stimulation of the phrenic nerve to assess the diaphragmatic strength in rabbits.

Diaphragmatic strength can be measured by transdiaphragmatic pressure during phrenic nerve stimulation. In order to avoid phrenic nerve dissection, a transjugular approach of the phrenic nerve can be performed. The objective of this study was to verify the identity of perinervous and transvenous techniques of phrenic nerve stimulation to assess diaphragmatic force.

Physiological effects and optimisation of nasal assist-control ventilation for patients with chronic obstructive pulmonary disease in respiratory failure.

Background: A study was undertaken to investigate the effects of non-invasive assist-control ventilation (ACV) by nasal mask on respiratory physiological parameters and comfort in acute on chronic respiratory failure (ACRF).

Methods: Fifteen patients with chronic obstructive pulmonary disease (COPD) were prospectively and randomly assigned to two non-invasive ventilation (NIV) sequences in spontaneous breathing (SB) and ACV mode. ACV settings were always optimised and therefore subsequently adjusted according to patient's tolerance and air leaks.

Selective resection of the phrenic nerve roots in rabbits. Part II: Respiratory effects.

This study evaluates the delayed respiratory consequences of selective resection of one or several roots of the right phrenic nerve in rabbits. A total of 50 animals were operated on according to five modalities of root resection. A total of 11 animals served as control.

Comparative physiologic effects of noninvasive assist-control and pressure support ventilation in acute hypercapnic respiratory failure.

Study Objective: To compare the effects of noninvasive assist-control ventilation (ACV) and pressure support ventilation (PSV) by nasal mask on respiratory physiologic parameters and comfort in acute hypercapnic respiratory failure (AHRF).

Design: A prospective randomized study.

Setting: A medical ICU.

Increased initial flow rate reduces inspiratory work of breathing during pressure support ventilation in patients with exacerbation of chronic obstructive pulmonary disease.

Objective: To investigate whether the level of initial flow rate alters the work of breathing in chronic obstructive pulmonary disease (COPD) patients ventilated in pressure support ventilation (PSV).

Design: Prospective study.

Settings: Medical ICU in University hospital.

Spatiotemporal gait parameters measured using the Bessou gait analyzer in 79 healthy subjects. Influence of age, stature, and gender. Study Group on Disabilities due to Musculoskeletal Disorders (Groupe de Recherche sur le Handicap de l'Appareil Locomoteur, GRHAL).

The Bessou gait analyzer provides quantitative measurements of spatiotemporal gait parameters. The purpose of this study was to determine whether and how these parameters are influenced by age, stature, and gender. Seventy-nine normal individuals (38 males aged 20 to 80 years and 41 females aged 20 to 80 years) were divided into ten-year age groups.

Respiratory response to CO2 in patients with chronic obstructive pulmonary disease in acute respiratory failure.

The aim of our study was to determine the importance of chemoreceptor stimulation by carbon dioxide in setting the level of ventilation in patients with chronic obstructive pulmonary disease (COPD) in acute respiratory failure. We studied the ventilatory and mouth occlusion pressure (P0.1) responses to CO2 in 25 COPD patients under treatment for episodes of acute respiratory failure, and in 24 normal subjects.

Surgical treatment of gastroesophageal reflux in ten patients with severe asthma.

The surgical cure of gastroesophageal reflux was investigated in 10 asthmatic adults with a mean post-operative follow-up period of 21 months. The patients had severe asthma, and gastroesophageal reflux confirmed by 3-hour post-prandial pH monitoring. Medical treatment for reflux was effective on the clinical signs of the reflux but ineffective on the respiratory signs.

[Gastroesophageal reflux during++ sleep in obese patients].

Evidence of relationship between gastrooesophageal reflux (GER) and obstructive apneas in some near-miss children, led us to investigate its possibility in adults. Our purpose was to look for 1) sleep stages of GER occurrence, and 2) the possible chronological link between sleep apneas and GER. Eight obese patients were investigated.

Radiopaque markers transit and anorectal manometry in 16 patients with multiple sclerosis and urinary bladder dysfunction.

Fecal incontinence and/or constipation are frequent complaints in multiple sclerosis associated with urinary bladder dysfunction, incontinence, and/or retention. Total and segmental colonic transit were studied by determination of radiopaque markers, and anorectal function by anorectal manometry, in 16 multiple sclerosis patients clinically defined (with urinary bladder dysfunction shown by urodynamic examination). Fifteen multiple sclerosis patients had constipation and 14 had increased colonic transit time; ten multiple sclerosis patients had fecal incontinence and five had spontaneous rectal contractions.

[Gastro-esophageal reflux and nocturnal sleep in the adult: method and results obtained in healthy subjects].

Esophageal pH has been studied at night in six healthy subjects. A pH electrode was placed 5 cm above the low esophageal sphincter and sleep state was monitored. The subjects were connected to the recording devices during two nights, but the recording was performed only during the second night.

[Can diminished bladder compliance favor spontaneous bladder rupture?].

A case of spontaneous rupture of the bladder was observed in a 53-year-old woman. Physical evaluation and diagnostic investigations showed the following findings: initial urinary retention presumed to be psychogenic as the patient had a confusional state and was free of anatomic or neurologic complications; low bladder compliance observed upon urodynamic investigation on the 21st postoperative day and one year later; repeated coughing fits due to chronic bronchitis at the time of the accident. Rupture of the bladder requires the coexistence of an obstacle to urinary outflow and decreased parietal resistance to distension upon filling.

[Exercise training for aged patients with respiratory insufficiency is possible. Apropos of 2 cases].

Two patients aged 69 and 75 respectively and suffering from chronic obstructive lung disease (Par CO2 7.8 and 9.2 kPa at rest) were trained on a treadmill for 6 months.

Nifedipine in chronic bronchial asthma: a randomized double-blind crossover trial against placebo.

Calcium-channel blockers such as verapamil and nifedipine have been shown to inhibit exercise-induced asthma as well as acutely induced bronchoconstriction, but little is known of their chronic effects, if any, on bronchial asthma. Nifedipine, 60 mg/day for 3 weeks, was compared to placebo in a double-blind randomized crossover study, as an addition to the usual treatment of 11 patients with severe chronic bronchial asthma. Nifedipine decreased the weekly duration of the attacks (102 +/- 34 vs 193 +/- 49 min, p less than 0.

[Postoperative gastrointestinal transit. Results of the measurement of segmental transit times].

The postoperative transit times of radioopaque markers through the gastrointestinal tract where measured in 6 patients after gastric surgery, in 13 patients after cholecystectomy, in 10 patients after appendicectomy and in 7 other patients who underwent general anesthesia without laparotomy. After ingestion of 20 markers, overall and segmental transit times were calculated according to their distribution on serial plain films of the abdomen taken 6 and 24 h after the operation, and every 24 h thereafter until complete evacuation of the markers. Overall transit times of the 3 groups of patients with laparotomy (171, 130 and 113 h respectively) were greater than overall transit times of patients without laparotomy (25 h).

Effect of brain-stem lesion on colonic and anorectal motility. Study of three patients.

The supraspinal control of colonic motility and anorectal motility is poorly documented. We had the opportunity to study colonic function, esophageal function, and urinary bladder function in three patients who presented with vascular lesions limited to the anterior (case 1) or the posterior area (cases 2 and 3) of the pons. Esophageal manometry, urodynamic examination, whole and segmental transit time measurements (using radiopaque markers) and anorectal motility were systematically performed.

[Anorectal motility in idiopathic constipation. Study of 200 consecutive patients].

The aim of our work was to study anorectal motility and tension of the rectal wall in 200 constipated adult patients. Anorectal manometry was normal in 88 patients (group A), showed abnormal amplitude of the anorectal inhibitory reflex in 33 patients (group B) and hypertonia and ultraslow waves in 70 patients (group C). These anomalies were: a) reproducible in the 20 patients studied twice; b) observed in patients with enterocolitis, thus not specific of constipation; c) associated with an increased frequency of fecal evacuation difficulties.