title: Transthoracic ultrasound assessment of B-lines for identifying the increment of extravascular lung water in shock patients requiring fluid resuscitation.
abstract: BACKGROUND
  Several studies have shown that the number of B-lines was related to the amount of extravascular lung water (EVLW). In our study, we aimed to demonstrate the magnitude of the incremental B-lines in shock patients with positive net fluid balance and the association with gas exchange impairment.
  
  
  METHODS
  We performed trans-thoracic ultrasound at admission (T0) and at follow-up period (TFL) to demonstrate the change of B lines (ΔB-lines) after fluid therapy. We compared the total B-line score (TBS) at T0 and TFL and calculated the Pearson's correlation coefficient between the ΔB-lines and PaO2/FiO2 ratio.
  
  
  RESULTS
  A total of 20 patients were analyzed. All patients had septic shock. Net fluid balance was + 2228.05 ± 1982.15 ml. The TBS at T0 and TFL were 36.6 ± 23.73 and 63.80 ± 29.25 (P < 0.01). The ΔB-lines along anterior axillary line (AAL) correlated to the ΔTBS (r = 0.90, P < 0.01). The ΔB-lines along AAL had inverse correlation to PaO2/FiO2 ratio (r = -0.704, P < 0.05). The increase of B-lines ≥ 10 was related to the decrease of PaO2/FiO2 ratio. The inter-observer reliability between two ultrasound readers was high (r = 0.92, P < 0.01).
  
  
  CONCLUSIONS
  The number of B-lines increased in shock patients with positive net fluid balance and correlated to impaired oxygenation. These data supported the benefit of ultrasound for assessing the EVLW.
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Pongdhep
authors.initials: P
authors.lastname: Theerawit
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Nutchanart
authors.initials: N
authors.lastname: Touman
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Yuda
authors.initials: Y
authors.lastname: Sutherasan
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Sumalee
authors.initials: S
authors.lastname: Kiatboonsri
keywords: extravascular lung water; lung comet; lung leakage; lung ultrasound; sonographic B-line