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C M Derks

Publications and source records attributed to C M Derks.

17 recordsLinked to original sources
PubMed1980

Distribution of ventilation-perfusion ratios in pneumonectomized dogs.

In this paper, the distribution of ventilation (VA) and of pulmonary perfusion (Q), gas exchanges, and the single breath CO diffusing capacity are measured in 8 dogs before and after left pneumonectomy. During surgery 4 dogs, in which the left pulmonary artery is clamped, and 4 other dogs in which the left mainstem bronchus is clamped, are studied. A minute ventilation (VE) is adjusted during the initial stage in each dog but it is kept constant for the other stages. For the entire group of dogs, the overall VE/Q varies from 0.8 to 3.0 in the baseline study. In the initial study, the perfusion distribution is unimodal and the ventilation distribution is unimodal or bimodal. The percentage of ventilation of the second mode correlates approximately with the overall VA/Q. After clamping the left pulmonary artery, the correlation between overall VA/Q, capillary shunt, and blood gases data is excellent and the ventilation and perfusion distributions are both bimodal. One perfusion mode is situated in the low VA/Q ratios while one ventilation mode is situated in the high VA/Q ratios. After clamping the left mainstem bronchus, the average anatomical shunt is 27%, the ventilation and perfusion are both bimodal, and the mean PaO2 is 55 mm Hg. Ultimately the ventilation and perfusion distributions tend to return to normal after pneumonectomy.

Animals↗
PubMed1980

Effect of body position and of respiratory frequency on distribution of pulmonary ventilation and perfusion in dogs.

Ventilation (VA) perfusion (Q) ratios distribution measured by the inert gases method is studied in 7 anesthetized dogs in supine position, in prone position at a respiratory frequency of 15 cpm, and in prone position at a respiratory frequency of 10 cpm so as to test the sensitivity of this VA/Q method. Despite the fact that the precise height-width characteristics of the distribution modes are unknown, our results show coherent changes and sensitivity of the log standard deviation of the perfusion curve, of the shunt, and of the dead space obtained with the inert gas method. After the change from supine to prone position, cardiac output increases, shunt, if it exists, diminishes, VA/Q ratios distribution becomes more uniform, and PaO2 increases and (A-a)DO2 decreases. When respiratory frequency changes from 15 to 10 cpm, cardiac output, shunt, and dead space decrease, VA/Q ratios distribution curves are slightly less homogeneous. PaO2 and PaCO2 show no significant variation. This study shows that distribution mode's characteristics can be considered as good and coherent approximations.

Animals↗
PubMed1979

Pulmonary neutral fat embolism in dogs.

Twenty-two adult dogs were each given a single, 30-minute injection of 1.5 ml/kg body weight of pure triolein, and their pulmonary, hepatic, renal, and cerebral morphology was observed for 1, 2, 3, 4, 5, 6, 15, 24, and 48 hours; 3,4, and 5 days; 1 and 2 weeks; and 1 month after the injection. A picture of massive capillary occlusion by lipid droplets was followed by rapidly resolvable inflammatory pneumopathy of granulomatous type, leaving a normal lung at the end of the experiment. The cleaning of the capillaries may be attributed to the mechanical action of the blood flow and to the inflammatory reaction with evacuation of necrotic cells via the bronchial route. Transient pulmonary edema is attributed to increased pulmonary arterial pressure. There was no intravacular coagulation. The few pulmonary lesions observed after the triolein injection suggest that the chemical theory of neutral fat hydrolysis by pulmonary lipase and the toxicity of free fatty acids that are released should be reconsidered.

Animals↗
PubMed1977

Respiratory mechanics measured by a simple device.

A simple and inexpensive apparatus is described which permits the semi-automatic measurements of pulmonary dynamic compliance (Cdyn) and airway resistance (Raw) while rapid changes of these factors during the experimental induction of pneumopathies can be followed. A diaphragm is used as a pneumotachograph because it was found to be quite sensitive and pulmonary secretions did not disturb the measurements. Volume base line drift is prevented.

Airway Resistance↗
PubMed1977

An automatic device for single-breath CO diffusing capacity in dogs.

We describe a very simply operated system by which single-breath CO diffusing capacity (DLCO) can be measured in anesthetized dogs. All controls and the automatic system are operated pneumatically. Cams forming an integral part of the pistons of the inspiratory and expiratory syringes activate push buttons which control the valves, enabling dead spaces to be flushed, a specific volume of air to be injected into the dog's lungs, and expiratory samples to be taken. Our results, due account being taken of the dogs' weight, are in the upper range of normal values published in earlier studies; the reproducibility of the method is good.

Animals↗
PubMed1977

Embolic pneumopathy induced by oleic acid. A systematic morphologic study.

This paper presents a systematic study of acute and chronic pulmonary lesions resulting from a single intravenous injection of oleic acid and a new fibrosis lung model is proposed: pulmonary interstitial fibrosis is obtained by means of a number of oleic acid intravenous injections. Nineteen adult dogs received 0.045 g/kg or 0.09 g/kg of oleic acid. A systematic morphologic study was carried out after 1, 2, 3, 4, 6, 12, 24, and 48 hours and 1, 2 and 4 weeks. Eleven other adult dogs received weekly one injection of 0.09 g/kg of pure oleic acid over a period of 1 to 3 months. Examination of the lung was carried out by means of light and electron microscopy and morphometry. An early stage characterized by the formation of thrombosis and cellular necrosis was followed by a repair stage with the proliferation of Type 2 cells and fibrotic foci in the subpleural areas. Lipid staining with Sudan IV allowed the onset and disappearance of lipid-laden macrophages to be ascertained. The late stage showed pulmonary fibrosis. The extent of the lesions is related to the number of oleic acid injections. Since interstitial pulmonary fibrosis invariably appeared, and only 2 dogs out of 11 died, the model is satisfactory for pathologist and physiologist.

Animals↗
PubMed1976

Extracorporeal oxygenation with various experimental venoarterial bypasses during prolonged apnea.

This work compares various conventional venoarterial closed-chest circuits where satisfactory oxygenation of myocardium and brain in total apnea with extracorporeal circulation is concerned. Eleven dogs were studied during 3 hours of curare-induced apnea. We used single and double vena caval drainages connected to an oxygenator. A single-vein drainage yielded approximately 50 per cent and a double-vein drainage 75 per cent bypass. Two separate roller pumps fed arterialized blood variously into carotid and femoral arteries. In single-vein drainage, the oxygen partial pressure in the coronary artery was consistently poor and carotid oxygen partial pressure was poor for 100 per cent femoral infusion while more and more arterialized blood reached the carotid arteries in the other single-vein drainage circuits. In double-vein drainage, the coronary oxygen partial pressure for 100 per cent femoral infusion remained poor while, for the other circuit types, the coronary arteries received arterialized blood except where 100 per cent carotid infusion was concerned. The carotid oxygen partial pressure was sound for all groups in the double-vein drainage except for some obtained in 100 per cent femoral infusion. Consequently, where the bypass was large and the carotid and femoral arteries received a share of arterialized blood, both heart and brain received sound oxygenation.

Animals↗
PubMedDate not supplied

Pathophysiology and morphometry of the early pulmonary fibrosis in dogs.

A physiological (hemodynamics, gas exchange and respiratory mechanics) and morphometric evaluation has been undertaken on six normal dogs (N) and seven dogs (F) whose lungs showed variable degrees of fibrosis produced by successive injections of oleic acid. The correlation between the degree of fibrosis and the ratio of measured to predicted alveolar surface was --0.97 (alpha < 0.01). Moderate pulmonary hypertension was present in group F. The greater the fibrosis, the more the volume/pressure curve was displaced downward and to the right. There was a good (positive or negative) correlation between the degree of fibrosis and the following data: expired quasi-static compliance, DLCO, PAO2, (A--a)Do2 and the intrapulmonary shunt. Except for the increase in shunt, the VA/Q distribution was not disturbed.

Animals↗