PURPOSE: Pleural fluid pH anaerobically handled and measured by a blood gas analyzer (BGA) has been reported to define a pleural space infection as complicated and predict the life expectancy of patients with malignant pleural effusions. However, pleural fluid pH can be measured by other methods that have been reported to be less accurate in the measurement of pleural fluid pH. It is unknown if physicians know how their laboratories measure pleural fluid pH thereby affecting the accuracy of their decision making. We evaluated physician's perceptions of pleural fluid pH measurement and the manner in which their local hospitals actually measure pleural fluid pH.
METHODS: We surveyed 90 pulmonary physicians in North Carolina via e-mail, fax, or telephone inquiring about their knowledge of how their hospital laboratory measures pleural fluid pH - via pH paper, meter, or BGA. We then contacted the individual hospital laboratories to determine the actual method of pH measurement.
RESULTS: 31% of pulmonologists in North Carolina (11 hospitals) responded to the survey, and 61% had inaccurate perceptions of how pleural fluid pH was measured. 25% had accurate perceptions, and 14% did not know the method of measurement by their hospital.71% reported their hospital measures pleural fluid pH via BGA (23% were accurate). 3.5% reported their hospital measures pleural fluid pH via pH paper (100% were accurate), and 3.5% reported their hospital measures pleural fluid pH via pH meter (100% were accurate).
CONCLUSION: Most hospitals did not use a BGA as the primary method of pleural fluid pH measurement, and the majority of physicians surveyed had inaccurate perceptions concerning the measurement of pleural fluid pH.
CLINICAL IMPLICATIONS: Clinical decisions are possibly being made based on data not supported by the literature, and physicians should be aware of the method utilized to measure pleural fluid pH by their hospital laboratory. This may represent a problem that extends outside of North Carolina. Further studies are needed and are forthcoming.
DISCLOSURE: Mark Bowling, No Financial Disclosure Information; No Product/Research Disclosure Information