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Novel swine influenza A: most frequent ultrasonographic lung patterns


Bedside lung ultrasound is able to identify with high sensibility and sensitivity most pulmonary pathological patterns and is widely adopted in critically ill patients' daily management. It is a feasible and reliable method for the identification of the lung pathological patterns caused by H1N1 influenza infection.


The study took place in the ICU of a regional referral center, with ECMO availability, for respiratory failure (Careggi Teaching Hospital, Florence, Italy). Eight patients admitted for H1N1-induced ARDS (September to October 2009) underwent daily LU examination. The examination was standardized with a procedure ad hoc in order to achieve complete and comparable reports for every patient. Patients were examined supine, taking lateral and anterior views and, if possible, on one side. Intercostal spaces were used as acoustic windows. Every single examination and its finding have been reported in our ICU database.


Pleural thickness was present in 100% of cases, mostly related to little and multiple pleural consolidations. Anyway, pleural gliding was present most of the time (87.5%), even if with a visible decrease of its movement. This was replaced with the lung pulse only in the presence of important lung consolidation. Alveolar interstitial syndrome (AIS) was always present on the whole lung, ranging from moderate to severe (100%), with high positivity at the base, posteriorly (100%). White lung appeared in every patient, most at the lung base and in the middle fields, posteriorly. As far as consolidation is concerned, its presence was confirmed in 100% of the patients, associated with satellite multiple subpleural consolidations in 37.5% of patients. Basal lung was always involved (100%), followed by middle (50%) and apical fields(25%). Bronchogram was present in 100% of patients in bigger consolidations. Their aspect was aerial and only in one patient, with severe consolidations, turned into a fluid one. Anechoic pleural effusions were found in 37.5% of patients. No cases of pneumothorax were detected.


In this group of patients, H1N1 infection shows different lung patterns altogether, where the most frequent seemed to be severe basal posterior AIS, multiple subpleural lung consolidations, and multiple parenchymal consolidation with bronchogram. The presence of spared areas did not seem to belong to H1N1 LU patterns.

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Correspondence to L Tutino.

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Tutino, L., Barbani, F., Cianchi, G. et al. Novel swine influenza A: most frequent ultrasonographic lung patterns. Crit Care 14, P89 (2010).

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  • Influenza
  • Swine Influenza
  • Lung Ultrasound
  • Pathological Pattern
  • Lung Consolidation