PulmCrit: Pulmonary Intensivist´s Blog
Pulm Crit: Pulmonary Intensivist´s Blog - February 1, 2015
"Recently point-of-care ultrasonography (POCUS) has risen in prominence within acute care medicine. It has been shown to provide immediate and critical information about a variety of conditions ranging from nephrolithiasis to pulmonary edema. However, POCUS is not without its critics, who point out weaknesses including detection of incidental findings (i.e., small post-traumatic pneumothorax or pleural effusions leading to unnecessary procedures). There has been much debate about which test is best for any given condition, for example chest X-ray (CXR) versus POCUS for the diagnosis of pneumonia.
When approaching a crashing patient with unclear diagnosis, these considerations are largely moot. First, it should be recognized that most crashing patients are suffering from some form of cardiopulmonary failure. Tamponade may manifest initially with dyspnea and tachypnea. Pulmonary embolism may cause hypotension without causing hypoxemia. Tension pneumothorax can present with simultaneous pulmonary and cardiac failure. Regardless, most crashing patients are suffering from some form of cardiac failure, pulmonary failure, or both. Until a definite diagnosis has been reached it may be best to conceptualize these patients as havingcardiopulmonary failure. Prematurely focusing on the wrong organ is a common pitfall."
Conclusions
- Most crashing patients are suffering from some form of cardiopulmonary failure (cardiac failure, pulmonary failure, or both). When in doubt it is safest to maintain a broad differential and evaluate both organs simultaneously.
- EKG, CXR, and POCUS can each reveal a wealth of information immediately at the bedside. For a patient with undifferentiated cardiopulmonary failure, immediately obtaining all three tests may be a safe approach to avoid missing anything.
- EKG, CXR, and POCUS should not be thought of as competitive with one another, but rather as synergistic and complementary. Integrating data from all three studies at the bedside is a very powerful approach.
- ABG may be useful to answer a specific clinical question. However, when applied without a specific indication to a patient with an unknown diagnosis, it usually adds little useful information.
- The diagnostic power of ABG is minimal compared to studies such as POCUS. There is no evidence supporting the use of ABG for a patient with undifferentiated respiratory failure, compared to impressive evidence supporting POCUS (e.g. Lichtenstein's Blue Protocol). A diagnostic approach to cardiopulmonary failure incorporating ABG without POCUS is outdated.
http://www.pulmcrit.org/2015/02/approaching-undifferentiated.html