OSIRIS-REx Contamination Control Strategy and Implementation.

OSIRIS-REx will return pristine samples of carbonaceous asteroid Bennu. This article describes how pristine was defined based on expectations of Bennu and on a realistic understanding of what is achievable with a constrained schedule and budget, and how that definition flowed to requirements and implementation. To return a pristine sample, the OSIRIS-REx spacecraft sampling hardware was maintained at level 100 A/2 and <180 ng/cm of amino acids and hydrazine on the sampler head through precision cleaning, control of materials, and vigilance.

Mechanical ventilation of the postoperative patient.

This article explains the operating characteristics of the most commonly used modes of mechanical ventilation and provides descriptions of how mechanical breaths are delivered. Also included are simple guidelines for choosing tidal volume, respiratory and flow rate, and alarm settings. The article concludes with a brief overview of weaning techniques and commonly used criteria to determine when patients are ready to be weaned from ventilating support.

Ventilatory support during magnetic resonance imaging.

Ventilatory support during magnetic resonance imaging is difficult because metallic objects on ventilatory support devices can interfere with the imaging field and/or become magnetized and move inside the patient or become flying projectiles. We report the successful MRI examination of an intubated respirator-dependent pediatric patient. Ventilatory support was carried out with a plastic ambu bag, exhalation valve circuit, and tubing.