Flow resistance of endotracheal tubes during kinking and compression. An experimental study.

Kinking and compression of endotracheal tubes may lead to serious problems. Such complications are assumed to occur more often for smaller endotracheal tubes used in adult practise in order to reduce to trauma of intubation. The effect of kinking and compression on the air-flow through PVC endotracheal tubes of various dimensions (inner diameter 6, 7, 8 and 9 mm) and types (manufactured by National Catheters, Portex and Shiley) has been studied in an experimental model. All tubes could be kinked surprisingly much before a measurable flow hindrance occurred. Only small differences were measured between different dimensions and types. In contrast smaller endotracheal tubes were considerable less resistant to edge compression than larger dimensions.