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Biomedical subjects

R Sergysels

Publications and source records attributed to R Sergysels.

At least 109 records · Page 6Linked to original sources

Effect of oxygen on breathing during exercise in patients with chronic obstructive lung disease.

In 10 exercising patients with chronic obstructive lung disease (COLD) we measured ventilation (VE), end-tidal CO2 (PETCO2), mean inspiratory flow (VT/TI), the ratio of inspiratory time to total time for one cycle (TI/TTOT), and occlusion pressure at 0.1 s measured at the mouth (P O.1), when they breathed room air and 100% oxygen. Oxygen breathing increased the maximal work load achieved. Furthermore, at the same exercise load, P O.1, VT/TI, VE, heart rate, respiratory frequency (f) decreased significantly in hyperoxia as compared with normoxia. Thoraco-pulmonary impedance assessed by P 0.1/VE and P 0.1/(VT/TI) ratios showed a slight but significant decrease to the respiratory centre. Thus in exercising patients affected by COLD, hyperoxia not only decreases the chemical afferent drive but also may slightly reduce the afferent mechanical drive to the respiratory centre. The decrease in the thoraco-pulmonary impedance may be explained either by an increase in efficiency of the respiratory muscles and/or a decrease in airway resistance.

Adult↗

Hemodynamic characteristics in chronic obstructive lung disease as related to cardiac size.

The hemodynamic adaptation during exercise was evaluated in 19 patients suffering from chronic obstructive lung disease. They were divided into two groups according to cardiac size on the X-ray (group 1, small; group 2, normal). A small cardio-thoracic ratio could be correlated with 'emphysema' assessed on the basis of hyperinflation and a low transfer test for CO. No clear-cut difference could be found between the two groups concerning the hemodynamic data at rest or during exercise. However, for all subjects, the cardiac output was found to be slightly related to the cardiac size (smaller cardiac output for smaller cardiac size). During exercise, a low cardiac output was characterized by a low oxygen transport and a high level of lactate. From this, it is suggested that a small cardiac size, a classical feature of hyperinflation and emphysema, may lead to a low cardiac output. The explanation for these results is speculative, but variable hemodynamic profiles in chronic obstructive lung disease with or without hyperinflation may be related to the morphology of the cardiac chambers and to variable intrathoracic pressure regimes during respiration.

Adult↗

Functional evaluation of tracheal stenosis before and after surgical management.

14 patients affected by tracheal stenosis resulting from assisted ventilation underwent a tracheal resection (n = 12) or dilatation (n = 2). Lung function tests were performed before and after surgical treatment. Prior to surgery, we observed a significant increase in airway resistance (Raw) in all subjects and a negative exponential relationship between Raw and FEV1/VC. Expiratory flows were also reduced with an increase in FEV1/PEFR ratios. After surgical correction of the stenosis, Raw normalized in 10 out of 14 subjects. The observed changes were more significant than for the other functional tests. After surgery, the patient's follow-up with Raw allowed the diagnosis of recurrent stenosis in 4 subjects lacking significant clinical symptoms. We conclude that measurement of Raw helps the clinical diagnosis and the appreciation of the possible changes in airway permeability after the surgical procedure.

Forced Expiratory Volume↗

[Use of injectable amiodarone in patients with chronic respiratory insufficiency].

Intravenous amiodarone (5 mg/kg) was administered to 10 patients with chronic obstructive airways disease, hypercapnia and hypoxia, and pulmonary hypertension. Respiratory function tests, arterial blood gases, ECG, blood pressure and subjective tolerance were monitored. Subjective tolerance was excellent. The parameters investigated showed no significant changes either biologically or statistically, excepting a slowing of the cardiac rhythm. The authors conclude that amiodarone has no undesirable cardiopulmonary side effects.

Aged↗

Low frequency breathing at rest and during exercise in severe chronic obstructive bronchitis.

The effect of low frequency breathing compared with spontaneous breathing was examined at rest and during exercise (40 watts) in 12 patients suffering from severe chronic obstructive bronchitis. At rest low frequency breathing improved significantly the alveolar ventilation and the tensions of oxygen and carbon dioxide in the arterial blood. There was no significant change in ventilation minute volume. During exercise low frequency breathing significantly decreased ventilation minute volume, and there was no significant improvement in gas exchange. The decrease in ventilation during low frequency breathing at 40 watts compared with spontaneous breathing at the same lung volume was due to expiratory flow limitation. The findings suggest that this technique may impair exercise tolerance in patients with severe chronic obstructive bronchitis.

Bronchitis↗

Functional evaluation of a physical rehabilitation program including breathing exercises and bicycle training in chronic obstructive lung disease.

20 patients suffering from chronic obstructive lung disease (COLD) were submitted to a 6-month rehabilitation program including breathing exercises only (A) or coupled with bicycle training (B). Functional results obtained at rest were the following: for A: nonsignificant changes in FRC, RV, FEV1, Raw, Pa O2, pH, Pp, VO2 max SL but significant changes (p less than 0.05)for TLC (+ 214 cm3), VC (+ 171 cm3), DL CO (+ 1.79 ml), Pa CO2 (-2.9 mm Hg). For B: similar changes as for A with additional significant changes in PaO2 (+ 7.4 mm Hg) VO2 max SL (+ 250 ml) and Pp (-4 mm Hg). These results, although minimal, are attributed to improved respiratory muscle strength and improved alveolar ventilation. Exercise training adds an increased ability to sustain higher loads.

Breathing Exercises↗

Effect of ventilation with different gas mixtures on experimental lung air embolism.

In six anesthetized, curarized and mechanically ventilated dogs, air was infused via a jugular vein at 0.1 cm3/kg/min for 25 min. This induced a progressive increase in pulmonary artery pressure (Pap) while arterial PO2 (PaO2) and end tidal PCO2 (PETCO2) decreased. Systemic arterial pressure, dynamic lung compliance and total pulmonary resistances were not affected. Changes tended to plateau by 20 min with a peak increase in Pap of 80 +/- 13% and decrease in PaO2 and PETCO2 of 22.2 +/- 2.8% and 14.5 +/- 2.1% respectively. When embolization was stopped these values returned to control levels within 30 min. During air infusion (at 20 min) some dogs were switched from ventilation with air to ventilation with the following gas mixtures: SF680%-O220%, He80%-O220%, N2O80%-O220%. During the final 5 min of air infusion. He and, to a greater extent, N2O breathing results in an immediate and marked further increase in Pap and decrease in PaO2 and PETCO2. In contrast SF6 produced rapid improvement in these parameters with return to near control levels. The recovery time after stopping infusion was greatly shortened with SF6 but was unaffected by He or N2O. These results are explained by different rates of gas transfer between the intravascular bubbles and the various alveolar gases. These findings show that ventilation with SF6 results in marked improvement in the gas exchange abnormalities produced by air embolism.

Animals↗

In vivo gas trapping induced by nitrous oxide.

Repeated vital capacity (VC) breaths in 17 anesthetized and curarized dogs induced a small but significant increase in residual volume (RV). This trapping was greatly enhanced when a mixture of 80% N2O and 20% O2 (N2O-O2) was used instead of air. VC breaths with N2O-O2 also increased closing volume, closing capacity and closing pressure determined with 133Xe. Successive quasi-static pressure volume (PV) curves of the lung showed a shift to the right at high lung volume and to the left at low lung volume. Again these changes were more impressive with N2O-O2). The PV curve of the chest wall was unchanged. Insufflations from RV were necessary to produce the gas trapping. Increase in RV was positively related to the size of the inspired volume, to N2O concentration, and inversely related to the inspiratory flow rate. Vagotomy, intravenous isoproterenol, and intravenous propanolol did not alter the phenomena. We propose that these observations can be explained by the presence of foam in the airways and that N2O leads to an increase of foam by osmotic liquid shift into the bronchioli, and/or to an increase in bubble's size by gas diffusion.

Animals↗

[Exercise retraining].

Among the essential positive facts resulting from the physical training of patients with moderate to severe obstructive bronchopneumopathy, the following should be noted:-- the maximal capacity for work increases on average by 10%;-- physiologically this increment of work maximal capacity corresponds simply to a better extraction of oxygen by the muscles;--no specific central haemodynamic modification is usually observed at maximum or sub-maximum level;-- after training there is a favourable evolution of the PaO2 at rest. In the absence of spirographic modification and diffusion capacity, this increase of PO2 seems to result from an improvement of the ratio ventilation/perfusion.

Carbon Dioxide↗

[Psychological rehabilitation of chronic pulmonary patients].

The readaptation of chronic pulmonary patients must be undertaken on a wide scope and particularly psychologically, considering the anxiety and immaturity of these patients. Whatever the length of the pulmonary disease and its treatment, they should benefit from a physical training together with a social and psychological help.

Anxiety↗

Pulmonary mechanics and diffusion after 'shock lung'.

Pulmonary function studies performed in seven patients who had recovered from 'shock lung' showed a highly significant decrease of diffusing properties of the lung, a slight loss of lung recoil pressure, and a borderline increase of residual volume with normal vital capacity and total lung capacity. Pulmonary compliance was normal. The interpretation of these findings is discussed.

Acute Disease↗