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Biomedical subjects

L Brochard

Publications and source records attributed to L Brochard.

123 records · Page 7Linked to original sources
PubMed1990

Reversal of acute exacerbations of chronic obstructive lung disease by inspiratory assistance with a face mask.

BACKGROUND: Patients with acute exacerbations of chronic obstructive pulmonary disease may require endotracheal intubation with mechanical ventilation. We designed, and here report on the efficacy of, a noninvasive ventilatory-assistance apparatus to provide inspiratory-pressure support by means of a face mask. METHODS: We assessed the short-term (45-minute) physiologic effects of the apparatus in 11 patients with acute exacerbations of chronic obstructive pulmonary disease and evaluated its therapeutic efficacy in 13 such patients (including 3 of the 11 in the physiologic study) who were treated for several days and compared with 13 matched historical-control patients. RESULTS: In the physiologic study, after 45 minutes of inspiratory positive airway pressure by face mask, the mean (+/- SD) arterial pH rose from 7.31 +/- 0.08 to 7.38 +/- 0.07 (P less than 0.01), the partial pressure of carbon dioxide fell from 68 +/- 17 mm Hg to 55 +/- 15 mm Hg (P less than 0.01), and the partial pressure of oxygen rose from 52 +/- 12 mm Hg to 69 +/- 16 mm Hg (P less than 0.05). These changes were accompanied by marked reductions in respiratory rate (from 31 +/- 7 to 21 +/- 9 breaths per minute, P less than 0.01). Only 1 of the 13 patients treated with inspiratory positive airway pressure needed tracheal intubation and mechanical ventilation, as compared with 11 of the 13 historical controls (P less than 0.001). Two patients in each group died. As compared with the controls, the treated patients had a more transient need for ventilatory assistance (3 +/- 1 vs. 12 +/- 11 days, P less than 0.01) and a shorter stay in the intensive care unit (7 +/- 3 vs. 19 +/- 13 days, P less than 0.01). CONCLUSIONS: Inspiratory positive airway pressure delivered by a face mask can obviate the need for conventional mechanical ventilation in patients with acute exacerbations of chronic obstructive pulmonary disease.

Acute Disease↗
PubMed1990

[Methods in mixed ventilation: advantages, disadvantages and consequences for work of breathing].

During partial ventilatory support modes both the ventilator and the patient are performing mechanical work. These modes are currently used as mechanical ventilatory support to provide a better synchronism between the patient and the machine and to avoid a complete rest of the respiratory muscles, or as modes of weaning from mechanical ventilation. Assist control ventilation allows the patient to regulate his own respiratory rate by triggering preset ventilatory cycles. Synchronized intermittent mandatory ventilation includes both controlled cycles and spontaneous breathing cycles. Lastly, during inspiratory pressure support, each spontaneous cycle is assisted by pressurization of the circuit. This latter modality alone seems efficiently to decrease the patients' breathing work while allowing complete synchronism between patient and ventilator.

Humans↗
PubMed1990

Cardiac asthma presenting as status asthmaticus: deleterious effect of epinephrine therapy.

Epinephrine is a potent bronchodilator currently used to treat severe asthma, although there is no proven advantage of this drug over beta 2 adrenergic agonists. By contrast, as demonstrated here, the use of such a potent vasoconstrictor can worsen hemodynamic status when left ventricular dysfunction is associated with asthma or is the cause for dyspnea. We describe the case of a 60-year-old man with an history of chronic asthmatic bronchitis admitted for status asthmaticus. Bronchodilator therapy, including high dosages of intravenous epinephrine, failed to improve the patient and he was intubated and mechanically ventilated. Several hours later, a right heart catheterization revealed severe unexpected left heart dysfunction with a capillary wedge pressure of 45 mmHg and a cardiac index of 1.7 l/min/m2. Epinephrine was gradually stopped which resulted in a decrease in mean arterial blood pressure and an improvement of hemodynamic status. He was discharged on home mechanical ventilation. In this patient, ischemic left heart failure was revealed by a clinical picture mimicking status asthmaticus. Epinephrine, given as bronchodilator therapy on an empiric basis precipitated the patient into cardiogenic shock. Therefore this drug should not be recommended in face of the possibility of cardiac asthma or associated cardiac dysfunction.

Diagnosis, Differential↗
PubMed1989

Severe hypokalaemic paralysis from an unusual cause mimicking the Guillain-Barré syndrome.

We report a case of hypokalaemic quadriparesis occurring 37 years after a bilateral ureterosigmoidostomy. The history and physical signs as well as cerebrospinal fluid analysis initially led to a diagnosis of Guillain-Barré syndrome. Acidosis and profound hypokalaemia were present and a dramatic improvement occurred after rapid correction of the potassium depletion. The underlying mechanism of potassium depletion which occurs after this mode of urinary diversion are briefly discussed.

Adult↗
PubMed1989

Inspiratory pressure support prevents diaphragmatic fatigue during weaning from mechanical ventilation.

Persistent inability to tolerate discontinuation from mechanical ventilation is frequently encountered in patients recovering from acute respiratory failure. We studied the ability of inspiratory pressure support, a new mode of ventilatory assistance, to promote a nonfatiguing respiratory muscle activity in eight patients unsuccessful at weaning from mechanical ventilation. During spontaneous breathing, seven of the eight patients demonstrated electromyographic signs of incipient diaphragmatic fatigue. During ventilation with pressure support at increasing levels, the work of breathing gradually decreased (p less than 0.02) as well as the oxygen consumption of the respiratory muscles (p less than 0.01), and electrical signs suggestive of diaphragmatic fatigue were no longer present. In addition, intrinsic positive end-expiratory pressure was progressively reduced. For each patient an optimal level of pressure support was found (as much as 20 cm H2O), identified as the lowest level maintaining diaphragmatic activity without fatigue. Above this level, diaphragmatic activity was further reduced and untoward effects such as hyperinflation and apnea occurred. When electrical diaphragmatic fatigue occurred, the activity of the sternocleidomastoid muscle was markedly increased, whereas it was minimal when the optimal level was reached. We conclude that in patients demonstrating difficulties in weaning from the ventilator: (1) pressure support ventilation can assist spontaneous breathing and avoid diaphragmatic fatigue (pressure support allows adjustment of the work of each breath to provide an optimal muscle load); (2) clinical monitoring of sternocleidomastoid muscle activity allows the required level of pressure support to be determined to prevent fatigue.

Acute Disease↗
PubMed1988

Early neutrophil alveolitis after rechallenge in drug induced alveolitis.

A patient with drug induced alveolitis due to an antidepressant drug, nomifensine, is described. After an inadvertent rechallenge by the patient sequential bronchoalveolar lavage was carried out. Twenty four hours after the rechallenge the lavage fluid contained a high cell count with neutrophils predominating. Seven days after challenge the cells were predominantly lymphocytes.

Alveolitis, Extrinsic Allergic↗
PubMed1987

Improved efficacy of spontaneous breathing with inspiratory pressure support.

During inspiratory pressure support (IPS) ventilation, first a negative airway pressure is produced by the patient to open a demand valve and then a constant positive airway pressure is maintained at a present level while the patient inhales. The aim of this study was to assess the ability of 10 cm H2O IPS to improve the efficacy of spontaneous ventilation. We studied 8 intubated patients recovering from acute respiratory failure, all were breathing spontaneously via 3 different systems: a Servo 900 C ventilator (SCV) without IPS, a Servo 900 C ventilator with 10 cm H2O IPS, and a continuous flow system (CFS). Compared with the CFS, breathing with the SVC without IPS resulted in an increased respiratory rate (RR), increased tidal Volume (VT), increased transdiaphragmatic pressure (Pdi), and no significant change in PaO2 or PaCO2. Ventilation with IPS resulted in significant improvements in VT, PaO2, and PaCO2 with a decreased RR and Pdi when compared with both the other modes of spontaneous ventilation. A significant decrease in the pressure-time index of the diaphragm (i.e., the product of the mean transdiaphragmatic pressure and the inspiratory duty cycle) occurred during IPS. In 2 patients, we recorded diaphragmatic electromyographic activity during both SVC and IPS. In both patients during IPS, an increased VT and a decreased Pdi coincided with a major reduction of electromyographic activity. We conclude that IPS at a level of 10 cm H2O markedly increases the efficacy of spontaneous breathing while reducing the activity of the inspiratory muscles.

Blood Gas Analysis↗
PubMed1987

High frequency chest wall oscillation in patients with chronic air-flow obstruction.

In order to assess high frequency chest wall oscillation (HFCWO) as a way to assist spontaneous breathing in obstructive lung disease, we studied 12 patients with severe and stable COPD. HFCWO at 5 Hz were applied by means of an inflatable vest. In order to avoid any discomfort, oscillations were applied only during the expiratory phase of the spontaneous breathing cycle. We compared gas exchange and pattern of breathing during control and HFCWO periods, each lasting 15 min. Minute ventilation did not change, but the pattern of breathing was markedly altered during HFCWO: breathing frequency decreased (p less than 0.001) from 18 +/- 6/min during control to 14 +/- 5/min, whereas tidal volume increased (p less than 0.01) from 600 +/- 200 ml during control to 860 +/- 400 ml. Secondary to this change in the pattern of breathing, arterial PO2 increased slightly (p less than 0.01) from 54 +/- 7 mm Hg during control to 57 +/- 8 mm Hg during HFCWO, and arterial PCO2 significantly (p less than 0.01) decreased from 46 +/- 6 mm Hg during control to 43 +/- 7 mm Hg during HFCWO. In addition, duty cycle (Ti/Ttot) decreased (p less than 0.001) from 0.37 +/- 0.03 s during control to 0.29 +/- 0.05 s during HFCWO. Such a decrease in duty cycle suggest that inspiratory muscle work was facilitated under HFCWO. In 8 patients, we obtained the tension-time index (TTdi), or the product of duty cycle and Pdi/Pdimax, and found that this index significantly decreased (p less than 0.05) from 0.06 +/- 0.03 during control to 0.04 +/- 0.02 during HFCWO.(ABSTRACT TRUNCATED AT 250 WORDS)

Dyspnea↗
PubMed1987

Density and frequency dependence of resistance in early airway obstruction.

The forced oscillation technique is a noninvasive and effort-independent test used to characterize the mechanical impedance of the respiratory system. The aim of this study was to assess the sensitivity of this method in detecting early airway abnormalities caused by smoking or occupational hazards. Respiratory mechanical parameters by the forced oscillation technique and maximal expiratory flow volume (MEFV) curves were obtained in a group of 82 workers from a gas manufacturing plant. In addition, the variations in the frequency dependence of total respiratory resistance between air breathing and a mixture of helium-oxygen (He-O2) were measured. All parameters were normalized for age, height, and weight. In order to compare the 2 types of testing, multiple linear regressions were performed with smoking or exposure as independent variables on one hand and parameters of the 2 types of testing on the other hand. This statistical procedure showed that 2 parameters of the forced oscillation technique constantly reached higher levels of significance than those of the MEFV parameters in the regression equations describing smoking history and occupational exposure: these were the frequency dependence of resistance and the change in frequency dependence between air and He-O2 breathing. When nonsmokers, ex-smokers, and smokers were considered separately, the degree of frequency dependence of resistance and the change in frequency dependence between air and He-O2 breathing were the only parameters that were significantly different between these 3 groups (one-way analysis of variance).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

[Treatment of uncontrollable hemorrhage caused by esophageal varices in cirrhotics. Transhepatic embolization or emergency portal shunt].

The purpose of this study was to compare the results of two therapeutic methods used in an emergency to control oesophageal variceal bleeding resistant to medical treatment in cirrhotic patients: portal diversion (116 patients) or transhepatic embolization of the varices (84 patients). Portal diversion proved more effective in stopping the haemorrhage than embolization but the overall mortality rate was about the same with the two procedures. An analysis of the results taking into account the patient's condition failed to show any difference in mortality between the two methods. Indeed, the very high mortality rate in the most severely ill patients may oblige to question their usefulness in such cases. In the least severe patients, we prefer portal diversion which is quicker and can be performed at any time. In patients of the intermediate group transhepatic embolization seems to be less hazardous than portal diversion.

Embolization, Therapeutic↗
PubMed1986

[Evaluation of the efficacy of the surgical treatment of panlobular emphysema].

26 patients presenting with panlobular emphysema between 1978 and 1984 were submitted to a thoracotomy for surgical resection of their bullae. Pre-operative and post-operative evaluations of the following were made: The level of dyspnoea in 5 grades. The FEV1 (VEMS) the forced vital capacity (CVF) the functional residual capacity (CRF) measured plethysmographically, the residual volume (VR), the total lung capacity (CPT). Arterial blood gases. The presence of radiological signs of compression on pulmonary angiography and on plain chest radiographs: an index of compression rated 0 to 6 was defined at the outset. The subjects were split into 3 groups based on their post-operative respiratory function: Group 1: no improvement (n = 7). Group 2: moderate improvement of dyspnoea (n = 11). Group 3: a big improvement in dyspnoea (n = 7). These three groups were homogenous as regards their preoperative respiratory function. On the other hand, the compression caused by the bullae based on the pre-operative radiological data was much greater (p 0.01) in the group of patients who improved. In addition when the index of compression was equal or superior to 3 (n = 14) all the patients were improved (n = 6). The comparison of pre- and post-operative values shows the following results: The change in blood gases was very limited in all groups; the ventilatory parameters were unchanged in group 1; on the other hand in group 2 and 3 one notes an overall improvement in pulmonary function. The size of the improvement however, was very variable from one individual to another.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Lithium causing a serious sinus-node dysfunction at therapeutic doses.

The cardiovascular effects of lithium have been indexed in literature since 1900, most frequently in cases of intoxication. We recently studied the exceptional case of a patient showing a serious sinus node dysfunction during lithium treatment. The serum lithium levels were always within the therapeutic range. After two endocardial explorations and withdrawal of lithium, we found that the sinus node dysfunction was due to lithium and reversible after withdrawal of it. Some ignored dysfunctions could exist with a regularly controlled treatment.

Ajmaline↗