Department of Emergency Medicine, A, Gemelli University Hospital, Rome, Italy.
Crit Care. 2012 Feb 17;16(1):R30. doi: 10.1186/cc11201.
The clinical picture of the pandemic influenza A (H1N1)v ranges from a self-limiting afebrile infection to a rapidly progressive pneumonia. Prompt diagnosis and well-timed treatment are recommended. Chest radiography (CRx) often fails to detect the early interstitial stage. The aim of this study was to evaluate the role of bedside chest ultrasonography (US) in the early management of the 2009 influenza A (H1N1)v infection.
98 patients who arrived in the Emergency Department complaining of influenza-like symptoms were enrolled in the study. Patients not displaying symptoms of acute respiratory distress were discharged without further investigations. Among patients with clinical suggestion of a community-acquired pneumonia, cases encountering other diagnoses or comorbidities were excluded from the study. Clinical history, laboratory tests, CRx, and computed tomography (CT) scan, if indicated, contributed to define the diagnosis of pneumonia in the remaining patients. Chest US was performed by an emergency physician, looking for presence of interstitial syndrome, alveolar consolidation, pleural line abnormalities, and pleural effusion, in 34 patients with a final diagnosis of pneumonia, in 16 having normal initial CRx, and in 33 without pneumonia, as controls.
Chest US was carried out without discomfort in all subjects, requiring a relatively short time (9 minutes; range, 7 to 13 minutes). An abnormal US pattern was detected in 32 of 34 patients with pneumonia (94.1%). A prevalent US pattern of interstitial syndrome was depicted in 15 of 16 patients with normal initial CRx, of whom 10 (62.5%) had a final diagnosis of viral (H1N1) pneumonia. Patients with pneumonia and abnormal initial CRx, of whom only four had a final diagnosis of viral (H1N1) pneumonia (22.2%; P<0.05), mainly displayed an US pattern of alveolar consolidation. Finally, a positive US pattern of interstitial syndrome was found in five of 33 controls (15.1%). False negatives were found in two (5.9%) of 34 cases, and false positives, in five (15.1%) of 33 cases, with sensitivity of 94.1%, specificity of 84.8%, positive predictive value of 86.5%, and negative predictive value of 93.3%.
Bedside chest US represents an effective tool for diagnosing pneumonia in the Emergency Department. It can accurately provide early-stage detection of patients with (H1N1)v pneumonia having an initial normal CRx. Its routine integration into their clinical management is proposed.
大流行性甲型流感（H1N1）v 的临床特征从自限性无热感染到快速进展性肺炎不等。建议及时诊断和治疗。胸部 X 线摄影（CRx）常不能发现早期间质期。本研究旨在评估床边胸部超声（US）在 2009 年甲型流感（H1N1）v 感染早期管理中的作用。
98 例因流感样症状到急诊科就诊的患者入组本研究。无急性呼吸窘迫症状的患者出院，无需进一步检查。对于有社区获得性肺炎临床提示的患者，排除伴有其他诊断或合并症的病例。临床病史、实验室检查、CRx 和计算机断层扫描（CT），如果需要，有助于确定其余患者肺炎的诊断。由一名急诊医生进行胸部 US，在 34 例最终诊断为肺炎的患者、16 例初始 CRx 正常的患者和 33 例无肺炎的患者中，寻找间质综合征、肺泡实变、胸膜线异常和胸腔积液的存在。
所有患者均能舒适地进行胸部 US，耗时相对较短（9 分钟；范围 7 至 13 分钟）。34 例肺炎患者中有 32 例（94.1%）出现异常 US 模式。16 例初始 CRx 正常的患者中，有 15 例（62.5%）表现出弥漫性间质综合征，其中 10 例（62.5%）最终诊断为病毒性（H1N1）肺炎。初始 CRx 异常的肺炎患者中，仅有 4 例（22.2%）最终诊断为病毒性（H1N1）肺炎（P<0.05），主要表现为肺泡实变的 US 模式。最后，33 例对照组中有 5 例（15.1%）出现弥漫性间质综合征的阳性 US 模式。34 例中有 2 例（5.9%）出现假阴性，33 例中有 5 例（15.1%）出现假阳性，敏感性为 94.1%，特异性为 84.8%，阳性预测值为 86.5%，阴性预测值为 93.3%。
床边胸部 US 是急诊科诊断肺炎的有效工具。它可以准确地提供初始 CRx 正常的（H1N1）v 肺炎患者的早期检测。建议将其常规纳入临床管理中。
