PURPOSE:Pleural fluid pH anaerobically measured by a blood gas analyzer (BGA) is the preferred pleural fluid chemistry test to define a pleural space infection as complicated. Recent observations indicate North Carolina pulmonary physicians have inaccurate perceptions concerning the use of BGA in measuring pleural fluid pH by hospital laboratories. It is unknown whether this discordance between physicians’ perceptions versus the reality of pleural fluid pH measurement exists throughout the United States.
METHODS:We surveyed 1500 pulmonary physicians in 49 states and Washington DC via e-mail asking the following: Do you use pleural fluid pH to manage complicated parapneumonic effusions? How does your hospital measure pleural fluid pH (BGA, pH meter, or indicator stick)? We then contacted these physicians’ individual hospital laboratories to determine the actual method of pH measurement and compared physicians’ perceptions with actual laboratory approaches.
RESULTS:Twenty three percent (344) of surveyed pulmonologists responded, and 88% (246) use pleural fluid pH measurement to manage complicated parapneumonic effusions. Of this group 55% (153) perceived that their laboratory was using a BGA to measure pleural fluid pH, but 35% (53) were mistaken. Two hundred and thirteen laboratories were identified based on the responding pulmonologists location of care (126 university and 87 community institutions), and 50% (106) reported using methods other than BGA to measure pleural fluid pH ( 23% (56) pH indicator stick and 26% (50) pH meter). This finding was similar between university and community hospital laboratories.
CONCLUSION:The majority of pulmonologists use pleural fluid pH to manage complicated parapneumonic effusions and believe that their laboratory measures pleural fluid pH via BGA. However, 1/3rd were inaccurate in their perception. Additionally, half of the surveyed laboratories do not utilize BGA to measure pleural fluid pH.
CLINICAL IMPLICATIONS:Clinical decisions concerning the management of complicated parapneumonic effusions is often based, at least partly, on erroneous pH data. Nationally, laboratories and physicians should be aware of this, and obstacles to appropriate pleural fluid pH measurement via BGA should be identified and addressed.
DISCLOSURE:Mark Bowling, No Financial Disclosure Information; No Product/Research Disclosure Information