INSPIRATORY VALVE MALFUNCTION IN THE DRAEGER RESPIRATORY CIRCUIT - ANEXAMPLE OF RISKS DUE TO BORDERLINE DAMAGE TO PARTS OF VENTILATORY EQUIPMENT

Unnoticed, minor damage to the unidirectional respiratory valves of th e Draeger respiratory circuit may lead to intermittent and unpredictab le malfunction, resulting in rebreathing and hypercapnia. The damage m ay be so minor that normal visual and functional test routines may be insufficient to detect it. We report one case of a potential life-thre atening malfunction of the inspiratory valve and also propose economic al solutions utilizing altered construction, modified machine-check pr ocedures, or a simple instrument that adds only one step to the machin e-check procedure. The general problem of minor but functionally impor tant damage to parts of ventilatory equipment - so-called borderline d amage - may not be limited to this particular model or manufacturer. M ost users of ventilatory equipment believe that equipment that goes th rough normal check procedures is either fully functional or nonfunctio nal. In reality, this is not the case. Intermittent malfunctions due t o slightly damaged equipment may be missed with normal machine-check p rocedures. This problem results in a significant but incalculable incr eased in risk to patients. Because of unclear reproduceability of inte rmittent malfunctions caused by borderline damage, there also is an in creased forensic risk for the anaesthesiologist. The risk of mechanica l malfunction might be displaced by software problems in new-generatio n ventilators in the market.