Neonatal pneumothorax drainage systems: in vitro evaluation.

We studied, in vitro, different commercially available components for pneumothorax drainage, i.e. drainage tubes, Heimlich flutter valve and vacuum control units. The drainage of a pneumothorax by a drainage tube was, as expected, directly dependent on Poiseuille's law and was influenced more by diameter than length. Of practical importance, a size 6 French gauge tube, used for the very small newborn, may not efficiently evacuate a pneumothorax due to a large air leak. The Heimlich flutter valve, though useful clinically, adds to the resistance of the system especially if fluids accumulate in the valve. All vacuum control units, adaptations of the basic three- or four-bottle pleural drainage system, functioned adequately but simple changes in construction may increase the safety of some of these systems.