Bulletin européen de physiopathologie respiratoire
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Bull Eur Physiopathol Respir · May 1985
Complement activation in the adult respiratory distress syndrome following cardiopulmonary bypass.
We investigated complement fractions in patients after extracorporeal circulation for coronary bypass operations or cardiac valve replacement, and in two cases developing an adult respiratory distress syndrome (ARDS) after this type of intervention. The patients presenting an ARDS had significantly increased levels of C3d (p less than 0.001), the small molecular breakdown product of C3, associated with decreased levels of total classic haemolytic activity (p less than 0.05) and of the complement component C1q (p less than 0.001) when compared to a group of 10 patients who had uneventful evolution after bypass. However, all patients undergoing cardiopulmonary bypass had significantly increased levels of C3d (p less than 0.005 or less) associated with significant decrease of various complement components within 24 h after bypass, when compared to a control group of 5 patients investigated after aorto-iliac bypass graft surgery. We conclude that significant complement activation can persist in patients 24 h after bypass and--at higher levels--be a pathogenic and biological marker of ARDS after extracorporeal circulation.
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Bull Eur Physiopathol Respir · May 1985
[Effect of artificial ventilation with an end-expiratory plateau on gas exchange amd hemodynamics in chronic respiratory failure].
Previous studies of pulmonary models and with animals have shown that in obstructive disease of the airways, ventilation with an end-expiratory plateau improves ventilation distribution. Paradoxically, there has been no data published on patients with obstructive disease. For this reason, we examined the effects of mechanical ventilation with an end-expiratory plateau on gas exchange and haemodynamics in 12 patients presenting acute exacerbations of chronic respiratory failure. ⋯ However, no matter which plateau is used, cardiac output decreases by more than 10% in six patients, probably due to a drop in systemic venous return. PaCO2 increase is too slight to hinder a decrease in arterial oxygen transport. The variability of these results accounts for patient diversity and restricts the indication of end-expiratory plateau to patients with severe ventilatory distribution disturbances who can benefit from close cardiorespiratory monitoring.
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Bull Eur Physiopathol Respir · May 1985
ReviewVentilatory support for pulmonary failure of the head trauma patient.
Severe head trauma patients frequently develop pulmonary failure. The aetiology of this respiratory distress may be central (neurogenic pulmonary oedema, delayed neurogenic pulmonary dysfunction, abnormal respiratory patterns) or peripheral, due to chest trauma, multiple trauma or lung infection. Hypoxia and hypercarbia alter cerebral haemodynamics, increase intracranial pressure and cause secondary deterioration of neurological function. ⋯ The effects of PEEP on cerebral perfusion pressure and on intracranial pressure depend on the interaction of pulmonary compliance, cerebral pressure/volume relationship and cerebral vascular autoregulation. High levels of PEEP may be deleterious in patients with altered cerebral autoregulation. High frequency ventilation theoretically has less influence on intrathoracic pressures and on cerebral haemodynamics but has not been shown superior in the respiratory support of severe head trauma patients.
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Bull Eur Physiopathol Respir · May 1985
Comparative StudyConstant mean airway pressure with different patterns of positive pressure breathing during the adult respiratory distress syndrome.
Twenty-one ARDS patients were divided into two groups of severity according to FIO2 and PEEP required to maintain an adequate gas exchange. The 10 most severe patients (group A) underwent continuous positive pressure ventilation (CPPV) (I/E 3:1) with the mean airway pressure maintained at 21 +/- 6.2 cmH2O. The PEEP values were 12.6 +/- 4.3 cmH2O during CPPV and 6.5 +/- 3.7 cmH2O during IRV (p less than 0.01). ⋯ In five patients of each group, the SF6 shunt was measured as representative of true shunt. The results showed that gas exchange, including true shunt, and haemodynamics did not change between CPPV and IRV and between CPPV and CPAP tests. Taken with previous work on mean airway pressure, our results further support the concept that the main determinant of oxygenation and haemodynamics is the mean airway pressure, irrespective of the PEEP level and of the mode of ventilation.