Focused cardiac ultrasound: uncommon but critical diagnoses made at the point of care.

Cardiovascular and respiratory conditions in acute care require rapid, critical decision making, often with limited clinical information. Focused cardiac ultrasound (FOCUS) can aid in diagnosis by providing information that may not be evident from a patient's medical history, physical examination, and ancillary tests. Eight cases are presented in which FOCUS drastically altered the management of patient care, shortened the differential diagnosis, or allowed for the development of a definitive diagnosis. In 3 cases, diagnoses that were not initially suspected were identified by FOCUS. In the remaining cases, uncommon yet critical diagnoses were established at early stages along the patients' courses of care.