Although there is a paucity of data to support this, it would be logical to include other patients with organic brain disease, such as Acute Respiratory Illness in Immunocompetent Patients stroke and delirium, in addition to dementia, as also having a high pretest probability of PNA despite otherwise negative physical examination findings and normal vital signs. CT Chest Our literature search failed to identify any data that suggest that CT serves any significant role in the initial imaging of immunocompetent patients with a high pretest probability of PNA. The role of CT for patients with a negative or equivocal initial chest radiograph is discussed in Variant 3. US Chest One prospective multicenter study performed by Reissig et al [11] enrolled 362 patients with abnormal vital signs or physical examination findings in addition to ARI symptoms. Patients received a two-view chest radiograph and a US. In cases in which the chest radiograph was negative or inconclusive and the US was positive, a chest CT was performed. This study demonstrated US sensitivity and specificity of 93.4% and 97.7%, respectively; however, these values are almost certainly overestimated because of the fact that a chest radiograph, rather than CT, was used as the reference standard in all cases except those in which there was discordance between an inconclusive or negative chest radiograph and a positive US. Bourcier et al [8] studied US and chest radiographs in a similar patient population. The final diagnosis was based on a chart review made by an independent expert and included clinical findings, labs, chest radiographs, and CT, if available. US in this study again demonstrated superior sensitivity for PNA relative to chest radiographs. Like Reissig et al, this study was limited by the lack of a consistent end point. Even with these limitations, the results of these studies suggest bedside US can be a useful tool for evaluating certain patients with a high pretest probability of PNA.
Acute Respiratory Illness in Immunocompetent Patients. Although there is a paucity of data to support this, it would be logical to include other patients with organic brain disease, such as Acute Respiratory Illness in Immunocompetent Patients stroke and delirium, in addition to dementia, as also having a high pretest probability of PNA despite otherwise negative physical examination findings and normal vital signs. CT Chest Our literature search failed to identify any data that suggest that CT serves any significant role in the initial imaging of immunocompetent patients with a high pretest probability of PNA. The role of CT for patients with a negative or equivocal initial chest radiograph is discussed in Variant 3. US Chest One prospective multicenter study performed by Reissig et al [11] enrolled 362 patients with abnormal vital signs or physical examination findings in addition to ARI symptoms. Patients received a two-view chest radiograph and a US. In cases in which the chest radiograph was negative or inconclusive and the US was positive, a chest CT was performed. This study demonstrated US sensitivity and specificity of 93.4% and 97.7%, respectively; however, these values are almost certainly overestimated because of the fact that a chest radiograph, rather than CT, was used as the reference standard in all cases except those in which there was discordance between an inconclusive or negative chest radiograph and a positive US. Bourcier et al [8] studied US and chest radiographs in a similar patient population. The final diagnosis was based on a chart review made by an independent expert and included clinical findings, labs, chest radiographs, and CT, if available. US in this study again demonstrated superior sensitivity for PNA relative to chest radiographs. Like Reissig et al, this study was limited by the lack of a consistent end point. Even with these limitations, the results of these studies suggest bedside US can be a useful tool for evaluating certain patients with a high pretest probability of PNA.