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Biomedical subjects

G Bonmarchand

Publications and source records attributed to G Bonmarchand.

At least 37 records · Page 2Linked to original sources
PubMed1997

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. RESULTS: ACV significantly decreased all the total inspiratory work of breathing (WOBinsp) parameters, pressure time product, and oesophageal pressure variation in comparison with SB mode. The ACV mode also resulted in a significant reduction in surface diaphragmatic electromyographic activity to 36% of the control values and significantly improved the breathing pattern. SB did not change the arterial blood gas tensions from baseline values whereas ACV significantly improved both the PaO2 from a mean (SD) of 8.45 (2.95) kPa to 13.31 (2.15) kPa, PaCO2 from 9.52 (1.61) kPa to 7.39 (1.39) kPa, and the pH from 7.32 (0.03) to 7.40 (0.07). The respiratory comfort was significantly lower with ACV than with SB. CONCLUSIONS: This study shows that the clinical benefit of non-invasive ACV in the management of ACRF in patients with COPD results in a reduced inspiratory muscle activity providing an improvement in breathing pattern and gas exchange. Despite respiratory discomfort, the muscle rest provided appears sufficient when ACV settings are optimised.

Acute Disease↗
PubMed1997

Gut ischemia and mesenteric synthesis of inflammatory cytokines after hemorrhagic or endotoxic shock.

The intestine plays a major role in the pathophysiology of multiorgan failure. Although the systemic inflammatory response might be induced by endotoxin released through bacterial translocation, other factors such as intestinal ischemia might be implicated. We investigated the relationship between intestinal ischemia-reperfusion and cytokine release in rat models of hemorrhagic or endotoxic shock. Plasma levels of tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), lactate, and endotoxin, as well as macrophage TNF-alpha and IL-6 mRNA expression, were assessed at the end of shock and resuscitation. Hemodynamic changes and lactate levels suggested the presence of intestinal ischemia in both models. Mesenteric levels of TNF-alpha and IL-6 were increased by hemorrhage and further increased after saline resuscitation. Similar results were obtained with mRNA cytokine gene expression in macrophages. Endotoxin was not detectable in the hemorrhagic group. Endotoxic shock also increased production of cytokines, which, in contrast to hemorrhage, was not further increased by resuscitation. These results suggest that intestinal ischemia-reperfusion upon hemorrhage and resuscitation may be a major trigger for cytokine gene expression in the absence of endotoxin.

Animals↗
PubMed1997

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. PATIENTS AND INTERVENTIONS: Fifteen patients with COPD and AHRF were consecutively and randomly assigned to two noninvasive ventilation (NIV) sequences with ACV and PSV mode, spontaneous breathing (SB) via nasal mask being used as control. ACV and PSV settings were always subsequently adjusted according to patient's tolerance and air leaks. Fraction of inspired oxygen did not change between the sequences. MEASUREMENTS AND RESULTS: ACV and PSV mode strongly decreased the inspiratory effort in comparison with SB. The total inspiratory work of breathing (WOBinsp) expressed as WOBinsp/tidal volume (VT) and WOBinsp/respiratory rate (RR), the pressure time product (PTP), and esophageal pressure variations (deltaPes) were the most discriminant parameters (p<0.001). ACV most reduced WOBinsp/VT (p<0.05), deltaPes (p<0.05), and PTP (0.01) compared with PSV mode. The surface diaphragmatic electromyogram activity was also decreased >32% as compared with control values (p<0.01), with no difference between the two modes. Simultaneously, NIV significantly improved breathing pattern (p<0.01) with no difference between ACV and PSV for VT, RR, minute ventilation, and total cycle duration. As compared to SB, respiratory acidosis was similarly improved by both modes. The respiratory comfort assessed by visual analog scale was less with ACV (57.23+/-30.12 mm) than with SB (75.15+/-18.25 mm) (p<0.05) and PSV mode (81.62+/-25.2 mm) (p<0.01) in our patients. CONCLUSIONS: During NIV for AHRF using settings adapted to patient's clinical tolerance and mask air leaks, both ACV and PSV mode provide respiratory muscle rest and similarly improve breathing pattern and gas exchange. However, these physiologic effects are achieved with a lower inspiratory workload but at the expense of a higher respiratory discomfort with ACV than with PSV mode.

Acute Disease↗
PubMed1997

Syndrome of inappropriate secretion of antidiuretic hormone in two elderly women with elevated serum fluoxetine.

OBJECTIVE: Fluoxetine is widely prescribed for depressed patients. Hyponatremia secondary to inappropriate secretion of antidiuretic hormone has been reported in a few cases associated with routine use of fluoxetine, especially in elderly patients. The mechanism has been postulated to be linked to the inappropriate secretion of antidiuretic hormone. Serum concentrations of antidiuretic hormone and fluoxetine have not been reported in previously published reports. CASE REPORT: We report two new cases of severe and reversible hyponatremia associated with routine use of fluoxetine therapy in two elderly women. Fluoxetine-induced inappropriate secretion of antidiuretic hormone was confirmed by elevated serum concentrations of antidiuretic hormone and fluoxetine.

Aged↗
PubMed1996

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. PATIENTS: Eleven intubated COPD patients. METHODS: We modulated the initial flow rate in order to achieve seven different sequences. In each sequence, the plateau pressure was reached within a predetermined time: 0.1, 0.25, 0.50, 0.75, 1, 1.25 or 1.50 s. The more rapidly the pressure plateau was achieved, the higher was the initial flow rate. In each patient, the pressure support level was an invariable parameter. The order of the seven sequences for each patient was determined randomly. MEASUREMENTS AND RESULTS: Ten minutes after application of each initial flow rate, we measured the following parameters: inspiratory work of breathing, electromyogram (EMG) of the diaphragm (EMGdi), breathing pattern, and intrinsic positive end-expiratory pressure (PEEPi). Comparison between the means for each sequence and each variable measured was performed by two-way analysis of variance with internal comparisons between sequences by Duncan's test. The reduction of the initial flow rate induced a progressive increase in the values of the work of breathing, EMGdi, and mouth occlusion pressure (P 0.1). In contrast, the reduction of the initial flow rate did not induce any significant change in tidal volume, respiratory frequency or PEEPi. CONCLUSIONS: As the objective of PSV is to reduce the work of breathing, it seems logical to use the highest initial flow rate to induce the lowest possible work of breathing in COPD ventilated patients.

Aged↗
PubMed1996

Bordetella bronchoseptica pneumonia with shock in an immunocompetent patient.

Bordetella bronchoseptica is a rarely reported cause of human infection, but is a common respiratory tract commensal of mammals. Human infection with B. bronchoseptica is almost always associated with severe underlying disease and contact with an appropriate animal reservoir. We report a case of pneumonia with shock caused by B. bronchoseptica in an immunocompetent patient.

Animals↗
PubMed1995

Impact of cephaloridine on glutathione and related enzymes: comparison of in vivo and in vitro rat models.

The aim of this study was to investigate the early effects of cephaloridine (CPH) on glutathione-dependent phase II detoxification in the rat proximal tubular cell and to find an in vitro alternative to the in vivo model. The in vivo study was conducted in three groups of rats which received CPH at doses of 250, 500 or 750 mg/kg per day for 3 days, while another group received 500 mg/kg as a single dose. For the in vitro study, rat renal proximal tubular cultured cells were exposed to CPH at concentrations of 0.3, 0.6, 1, 1.7 mM for 24, 48 and 72 h. Glutathione-dependent detoxification was evaluated in vivo and in vitro on the basis of total intracellular glutathione (GSH), glutathione S-transferase (GST) and glutathione peroxidase (GPX). Glutathione reductase (GRED) and GST mRNA levels were also determined. Results of in vivo and in vitro models were comparable in terms of the early increase of GSH, GST and GRED. This increase had a bell-shaped dose-response with a maximum at 500 mg/kg in vivo and 1 mM in vitro. Beyond these doses, GSH and its dependent enzyme levels decreased, associated with cytotoxicity in vitro and renal insufficiency in vivo. The increased GST activity was associated with an increased level of GST7 in vivo and a markedly increased level of GST1-2 in vitro. We concluded that the in vitro model can be used as an alternative to animal experimentation to study glutathione-dependent detoxication. Low cytotoxic doses of CPH induced an early increase of glutathione phase II-dependent detoxification enzymes.

Animals↗
PubMed1994

Acute pancreatitis after carbamate insecticide intoxication.

A 29-year-old woman was admitted to the Rouen University Hospital for attempted suicide by ingestion of a carbamate insecticide (Temik G, containing 10% aldicarb). Cardio-respiratory arrest occurred at the second hour and acute necrotic hemorrhagic pancreatitis on the second day. Further evolution was uneventful, and the patient was discharged after 43 days. Carbamate intoxication was confirmed by high urinary aldicarb metabolite concentrations. Pseudocholinesterase levels took 77 days to return to normal. Carbamate pesticides share the same pancreatic risk as organophosphorus pesticides, and should be monitored similarly.

Acute Disease↗
PubMed1993

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. Carbon dioxide rebreathing tests were performed in the spontaneously breathing, intubated patients, after arterial blood gases had been quasi-normalized by mechanical ventilation, which allowed us to compare both groups at similar resting arterial carbon dioxide tension (PaCO2) and acid-base status. The slopes of the ventilatory responses were markedly lower in the patients (mean +/- SEM, 1.28 +/- 0.23 versus 12.53 +/- 1.13 l.min-1.kPa-1). The slopes of the P0.1 responses were lower in the patients (0.27 +/- 0.05 versus 0.45 +/- 0.05 kPa.kPa-1), but the absolute P0.1 values were not significantly different from the normals. Increasing PaCO2 from 5.3 to 8 kPa (40 to 60 mmHg) resulted in a mean increase of 34% in ventilation. These results show that CO2 drive is a major determinant of respiratory stimulation in many COPD patients with acute respiratory failure.

Acute Disease↗
PubMed1989

Motor abnormalities of digestive and urinary tracts in patients on ventilator for acute exacerbation of chronic obstructive pulmonary disease.

The frequency of digestive motor abnormalities was evaluated in 30 consecutive patients ventilated for acute exacerbation of chronic obstructive pulmonary disease. Total and segmental colonic transit times were investigated by radiopaque marker transit time in all patients. Eleven patients also had rectoanal and esophageal manometries, combined with urodynamic study in eight cases. The results show that total radiopaque marker transit time was increased, 201 +/- 14 hr (mean +/- SE), with two main regions of decreased transit rates: the right colon (42% of global transit time) and the rectosigmoid (36%). Delayed transit of radiopaque markers in nine of 11 cases was combined with esophageal motor dysfunction and absence of rectoanal inhibitory reflex. In three of eight cases there was disinhibition of urinary bladder contraction, and micturition was impossible in two of eight cases. We conclude that patients on ventilator for exacerbation of chronic obstructive pulmonary disease always have a delayed colonic transit time with diffuse digestive and bladder motor dysfunction.

Acute Disease↗
PubMed1989

Penetration of pefloxacin into bronchial secretions.

Twelve patients, intubated for acute exacerbation of chronic obstructive pulmonary disease, received six intravenous doses of 400 mg of pefloxacin at 12-h intervals. Samples of blood and bronchial secretions were taken simultaneously, before the injection and at 0.5, 3, 6, 9, and 12 h after the end of the sixth infusion. There was a large variation in pefloxacin levels in both serum and bronchial secretions. The mean concentrations of pefloxacin in bronchial secretions ranged from 6.51 to 11.1 micrograms/ml and were higher than the corresponding concentrations in serum at all times. Of 61 bronchial specimens, 48 (79%) contained more than 8 micrograms of the antibiotic per ml.

Adult↗
PubMed1988

Intrapulmonary haematoma complicating mechanical ventilation in patients with chronic obstructive pulmonary disease.

Intrapulmonary haematomas occurred during mechanical ventilation of two patients with advanced chronic obstructive pulmonary disease and bullous dystrophy. In both cases, the haematomas were revealed by blood-stained aspirates, a fall in haemoglobin level, and the appearance of radiological opacities. Haematoma occurrence in the area of a bulla which recently has rapidly increased in size, suggests that the haematoma is due to the rupture of stretched vessels embedded in the wall of the bulla.

Female↗