tailieunhanh - Core Topics in Operating Department Practice Anaesthesia and Critical Care – Part 9

Nó cũng hiểu rằng áp lực đường thở trong thông khí áp lực dương có thể gây tổn thương phổi do distenstion hơn và vỡ của các phế nang. Điều này có thể dẫn đến tràn khí màng phổi hoặc khí phế thũng phẫu thuật là không khí có thể theo dõi của các phế nang bị vỡ và vào các mô kẽ. | Mechanical ventilation of the patient 169 Barotrauma It is well understood that high airway pressures during positive pressure ventilation may cause lung injury due to over-distenstion and rupture of the alveoli. This can result in pneumothorax or surgical emphysema as the air can track out of the ruptured alveoli and into the interstitial tissues. This can be a result of peak inspiratory pressures or PEEP. The use of certain methods of ventilation for example BIPAP can reduce the incidence if not prevent barotraumas as the pressure exerted on the alveoli is set at a predetermined limit. Volutrauma Volume-controlled ventilation where tidal volumes are set can cause the patient to be at risk of volutrauma. Large volumes of air can cause over-expansion of the lungs causing injury. The ensuing lung injury manifests itself as pulmonary oedema due to increased alveolar-capillary permeability possibly due to stress failure and or inflammatory mediators causing epithelial and endothelial breaks Cooper 2004 . Atelectrauma Atelectrauma has been described as a consequence of continuous alveolar collapse and reexpansion. Slutsky and Tremblay 1999 examined this theory and reported that larger forces are needed to re-open a closed airway and the resultant shear forces at the boundary between aerated and collapsed alveoli could cause stress failure of the alveolar membrane and epithelial disruption . Steinberg et al. 2004 suggested that the application of PEEP may prevent atelec-trauma as it reduces end-expiratory alveolar collapse. Ventilator-associated pneumonia VAP Ventilator-associated pneumonia has been shown to cause both excess mortality and prolongation of hospital and ICU stay. Reduction in the use or duration of mechanical ventilation if possible would reduce the incident of ventilator-associated infection. This reduction in episodes of pneumonia is one of the arguments for increased use of non-invasive techniques for respiratory support in acute respiratory failure .