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Biomedical subjects

S Launois

Publications and source records attributed to S Launois.

11 recordsLinked to original sources
PubMed1995

[Hiccups in adults].

Hiccoughs are an involuntary spasmodic and coordinated contractions of the inspiratory muscles associated with a delayed and sudden closure of the glottis which is responsible for the characteristic noise. The pathophysiology of hiccoughs have not been elucidated. There have only been a few observations describing the sequence of inspiratory muscle activation and these suggest that the control of hiccoughs is within the central nervous system. The clinical circumstances associated with acute benign hiccoughs are both numerous and disparate. In these cases, when they stop spontaneously or as a result of simple physical manoeuvres hiccoughs do not require any particular medical attention. Chronic hiccoughs, defined as hiccoughs persisting for more than 24 hours or recurring as repetitive attacks are a rare phenomenon. The causes cover the whole of organic pathology. Systematic protocols of complementary examinations most often enable an underlying organic cause to be found. Amongst these, particular attention should be paid to oesophageal causes by the reason of their being the most frequent. An important place should be reserved for the aetiological treatment as is frequently enables a remission of chronic hiccough.

Acute Disease↗
PubMed1993

Hiccup in adults: an overview.

Hiccup is a forceful, involuntary inspiration commonly experienced by fetuses, children and adults. Its purpose is unknown and its pathophysiology still poorly understood. Short hiccup bouts are mostly associated with gastric distention or alcohol intake, resolve spontaneously or with simple folk remedies and do not require medical attention. In contrast, prolonged hiccup is a rare but disabling condition which can induce depression, weight loss and sleep deprivation. A wide variety of pathological conditions can cause chronic hiccup: myocardial infarction, brain tumour, renal failure, prostate cancer, abdominal surgery etc. Detailed medical history and physical examinations will often guide diagnostic investigations (abdominal ultrasound, chest or brain CT scan...). Gastric and duodenal ulcers, gastritis, oesophageal reflux and oesophagitis are commonly observed in chronic hiccup patients and upper gastrointestinal investigations (endoscopy, pH monitoring and manometry) should be included in the diagnostic evaluation systematically. Etiological treatment is not always available and chronic hiccup treatment has classically relied on metoclopramide and chlorpromazine. Recently, baclofen (LIORESAL) has emerged as a safe and often effective treatment.

Adult↗
PubMed1992

[Chronic hiccups].

We report 18 cases of chronic hiccup (defined as lasting for more than 48 hours) in adults. Among the numerous possible causes, reflux esophagitis proved to be by far the most frequent (50% of the cases). However, hiccup often initiated a self-perpetuating vicious circle. This is possibly because hiccup per se can give esophageal dyskinesia, which in turn leads to gastro-esophageal reflux. The treatment was difficult and whenever possible has been directed chiefly towards the cause. However hiccup remained intractable in many cases even after a possible cause had been adequately cured (e.g., successful Nissen procedure in reflux cases). Central nervous system depressants and myorelaxing drugs were not very helpful, except for baclofen (initial response rate = 60%).

Adult↗
PubMed1991

[The control of respiration in pulmonary fibrosis. The effect of O2 and CO2].

We have studied the mode of ventilation and chemosentivity in 10 patients suffering from pulmonary fibrosis. The total lung capacity was on average 63.5 +/- 8% of the predicted. Their static compliance was 0.078 +/- 0.05 l.cm of water. The patients were studied in the prone position breathing ambient air then on hyperoxia. The response to CO2 was assessed according to the rebreathing method of Read. The results of these patients were compared with those of 11 normal subjects. The ventilation at rest was normal, with a shortened respiratory time and a Ti/Ttot ratio which was lowered. The occlusion pressure (P0.1) was very much higher than that in normal subjects. This rise was correlated with an increase in pulmonary elastance and a reduction in vital capacity. The correction of hypoxia was without effect on the respiratory parameters. In relation to normal subjects the ventilatory response to carbon dioxide in fibrotics was decreased whilst the response of the P0.1 was increased expressing central hyperactivity. In conclusion, fibrotic patients have normal ventilation in spite of an increase in inspiratory work. This normal ventilation results from hyperactivity of the respiratory centre, as in the hyperventilation induced by carbon dioxide when at rest.

Adult↗
PubMed1990

The respiratory response to CO2 and O2 in patients with coma due to voluntary intoxication with barbiturates and carbamates.

We have investigated the respiratory response to CO2 and to O2 in comatose subjects self intoxicated with barbiturates and carbamates. The chemical drive of 12 such patients with coma was compared with that of comparable normal subjects. The ventilatory response to CO2 was depressed but the P0.1 response was of the same order of magnitude as in normals. O2 had little effect on the ventilatory parameters and occlusion pressure. There was no difference between the two groups of patients, indicating that the respiratory changes observed were more dependent on the intensity of the intoxication than on the nature of the drugs. In addition, mechanical factors seem mainly responsible for the depressed ventilatory response to CO2.

Adult↗
PubMed1990

The transition between apnoea and spontaneous ventilation in patients with coma due to voluntary intoxication with barbiturates and carbamates.

We have investigated the transition from apnoea to spontaneous breathing in five comatose patients self intoxicated with barbiturates and carbamates. All patients were apnoeic on admission, and were studied throughout the course of recovery. The transition between the first respiratory movements and a stable and nearly normal ventilation (stable respiratory activity) ranged from 15 to 105 min, a very short time compared to the duration of the apnoeic state that lasted 6 to 72 h from admission. Minute ventilation and occlusion pressure during the first respiratory movements were 6.3 +/- 2.7 l.min-1 and 1.35 +/- 0.45 kPa, respectively. These values increased by roughly 50 and 100% by the time stable respiratory activity was achieved. The increase in minute ventilation was entirely due to an increased inspiratory flow, in relation to a proportionate increase in occlusion pressure, and without significant changes in the respiratory times or in the effective elastance. We conclude that the transition between apnoea and stable respiratory activity is characterized by its rapidity, by the fact that respiratory times are fixed throughout the recovery process, and by the fact that effective elastance is high.

Adult↗
PubMed1990

Mechanics of the pharynx in patients with obstructive sleep apnea.

We describe a novel method for evaluating the location, closing pressure and compliance of collapsing segments in the passive pharyngeal airway of patients with OSA. Observation on 16 patients with obstructive sleep apnea, revealed that the site of collapse in 6 patients was exclusively in the nasopharynx, whereas oro- and hypo-pharyngeal sites were localized in others. We speculate that a segment with a high closing pressure predisposes to airway narrowing during normal breathing during sleep. We also speculate that compliance of the segment interacts with regional muscle force and intra-luminal pressure to determine airway size.

Air Pressure↗
PubMed1989

Cervical magnetic stimulation: a new painless method for bilateral phrenic nerve stimulation in conscious humans.

Assessing diaphragmatic contractility is a common goal in various situations. This assessment is mainly based on static or dynamic maximal voluntary maneuvers and twitch transdiaphragmatic pressures (Pdi) obtained by stimulation of the phrenic nerves (PS). PS eliminates the central components of diaphragmatic activation, but the available techniques of PS remain subject to some limitations. Transcutaneous PS is painful, and needle PS is potentially dangerous. Time-varying magnetic fields can stimulate nervous structures without pain and without adverse effects. In six subjects, we have studied cervical magnetic stimulation (CMS) as a method of PS. We have compared the stimulated Pdi (Pdistim) with the maximal Pdi obtained during static combined expulsive-Mueller maneuver (Pdimax) and with the Pdi generated during a sniff test (Pdisniff). CMS produced twitch Pdi averaging 33.4 +/- 9.7 cmH2O. Pdistim/Pdimax and Pdistim/Pdisniff were 24 +/- 6 and 41 +/- 14%, respectively. These values are comparable to those obtained in other studies with transcutaneous PS. They were highly reproducible in all the subjects. Electromyographic data provided evidence of bilateral maximal stimulation. CMS is a nonspecific method and may stimulate various nervous structures. However, diaphragmatic contraction was elicited by stimulation of the phrenic trunk, since the phrenicodiaphragmatic latencies (less than 7 ms) were in the range of values reported with direct stimulation of the trunk. Cocontraction of neck muscles, including the sternomastoid, was present, but its influence in the CMS-induced Pdi seems minimal. We conclude that magnetic stimulation is an easy, well-tolerated, reproducible safe, and valuable method to assess phrenic conduction and diaphragmatic twitch response.

Action Potentials↗
PubMed1989

[Effects after 3 months of uvulopalatopharyngoplasty in the treatment of obstructive sleep apnea syndromes in adults].

The results at three months of uvulopalatopharyngoplasty (UPPP) have been evaluated in thirty adult patients with an obstructive sleep apnoea syndrome (SAOS). For the group overall the mean apnoea index (IA) decreased from 57 apnoeas per hour and the mean maximal desaturation decreased to 60% post operatively. However in the overall results different individual facts overlap. 20 of the 30 patients, or 67%, have an IA post operatively of less than 50% of the pre-operative value (responders). 14 of these or 47% have a post operative IA of less than 10 apnoeas per hour, a value considered as non pathological. Finally 33% of the patients have no improvement in their post operative IA (non responders). A stricking diminution of nocturnal desaturation and of the disorganisation of sleep was seen in responders to UPPP. No predictive factor for the results of UPPP could be determined. This study shows that UPPP is an effective treatment in a large number of patients having SAOS at the price of minor and transitory complications.

Adult↗
PubMed1988

[Cervical magnetic stimulation. A new method of bilateral phrenic nerve stimulation for use in clinical practice].

The stimulation of the phrenic nerves in the neck is one of the techniques for the examination of diaphragmatic contractility. Current methods are restricted by their painful (transcutaneous stimulation) or even potentially dangerous nature (needle stimulation). We have tested both the feasibility and the validity of using magnetic stimulation (SMC) to stimulate the phrenic nerves. This method is painless and devoid of any side effects. Three healthy subjects have been studied using an EMG and transdiaphragmatic pressure measurements (Pdi.) Pdi values obtained by SMC (36.5 +/- 13.5 cm H2O) and their relation to maximal Pdi (22.6 +/- 7%) and to the Pdi at the time of maximal sniff-Pdi sniff (34.7 +/- 8%) were comparable to those values obtained using other methods and were reproducible. The preliminary results show that SMC is a technique for the study of the phrenic nerve and diaphragm which has the advantage of simplicity in use, is repeatable and is completely innocuous.

Adult↗