Perventricular closure of pulmonary stump in a 16-kg child.

Blind pouch formation of the pulmonary artery (PA) in patients having undergone a Fontan operation can present a serious risk for thromboembolic events. Either primary or secondary closure of this stump is necessary to reduce this risk. Unfortunately, secondary closure is oftentimes difficult due to the size and anatomy of the presenting patient. We describe the insertion of a muscular ventricular septal defect (VSD) device via a perventricular approach for successful closure of a pulmonary stump in a 3-year old, 16-kg child. To our knowledge, this is the first report of a perventricular approach for successful closure of a PA stump.

A metering rotary nanopump for microfluidic systems.

We describe the design, fabrication, and testing of a microfabricated metering rotary nanopump for the purpose of driving fluid flow in microfluidic devices. The miniature peristaltic pump is composed of a set of microfluidic channels wrapped in a helix around a central camshaft in which a non-cylindrical cam rotates. The cam compresses the helical channels to induce peristaltic flow as it is rotated. The polydimethylsiloxane (PDMS) nanopump design is able to produce intermittent delivery or removal of several nanolitres of fluid per revolution as well as consistent continuous flow rates ranging from as low as 15 nL min(-1) to above 1.0 µL min(-1). At back pressures encountered in typical microfluidic devices, the pump acts as a high impedance flow source. The durability, biocompatibility, ease of integration with soft-lithographic fabrication, the use of a simple rotary motor instead of multiple synchronized pneumatic or mechanical actuators, and the absence of power consumption or fluidic conductance in the resting state all contribute to a compact pump with a low cost of fabrication and versatile implementation. This suggests that the pump design may be useful for a wide variety of biological experiments and point of care devices.