Lung Water

Abstract

Newspaper headlines have greeted with circumspection the report from the Government Accountability Office on the United States Food and Drug Administration (FDA) processes to regulate medical devices. They used sentences such as “Left to the FDA’s own devices” 1 and “Is That Device Safe?” 2. Such headlines bring attention to the fact that FDA requirements for approval and clearance of medical devices are markedly different from those for drugs3, 4. Most new devices are cleared, not approved, through the premarket notification (510(k)) pathway. This is a FDA process based on the assumption that the majority of new devices are essentially equivalent to those already approved. Physiological monitors are usually among these, and frequently enter the market due to their substantial equivalence to previous models, with limited scrutiny of efficacy 3, 4. Thus, as new monitors are introduced, it is crucial for good clinical practice to understand their principles, advantages and limitations. In this issue of Anesthesiology, Easley et al.5 apply functional lung imaging techniques to study measurements of extravascular lung water (EVLW) using the single indicator (iced saline) transpulmonary thermodilution method. The device was recently cleared by the FDA (PiCCO, Pulsion Medical Systems, Munich, Germany).