Increased capillary permeability may occur from a number of putative mechanisms in poisoning. These include direct toxic effects on endothelial cells (e.g. salicylates) or pneumocytes (e.g. hydrocarbons), vascular effects (e.g. calcium channel blocking drugs) and platelet activation secondary to any severe generalised illness causing tissue hypoxia. In general, whatever the mechanism, it only occurs in severe poisonings. Thus, if there are specific antidotes or means of elimination enhancement these are indicated (e.g. haemodialysis for salicylate poisoning).
Otherwise the treatment comprises respiratory support. Oxygen is given to maintain arterial oxygen. If 50% oxygen is insufficient to maintain arterial oxygen saturation above 90%, then assisted ventilation is required. Positive end expiratory pressure (PEEP) maximises oxygenation for a given inspired oxygen thus minimising oxygen toxicity. Oxygen toxicity may lead to or exacerbate ARDS and is dependent on both concentration and time of exposure).