Evaluating Extravascular Lung Water in Sepsis: Three Lung-Ultrasound Techniques Compared against Transpulmonary Thermodilution

This is the authors' abstract. We don't add key points for this paper.

Following sepsis, defined as life-threatening organ dysfunction caused by a dysregulated host response to infection, fluid resuscitation can be acutely lifesaving. However, excessive extravascular lung water (EVLW) is associated with subsequent organ dysfunction and increased mortality. ccordingly, clinicians need to be able to detect excessive EVLW if they are to achieve clinical balance in order to maximize the likelihood of patient rescue. Several techniques exist, but all have limitations. For example, chest X-ray and physical examination are limited by their inability to detect EVLW during early stages Transpulmonary thermodilution (TPTD), We compared three lung-ultrasound (L-US) techniques against the reference-standard transpulmonary thermodilution (TPTD) technique to access EVLW. Materials and Methods: This was a prospective, single-blind, cross-sectional study. Forty-four septic patients were enrolled. EVLW index was measured by the TPTD method, and an index of 10 mL/kg was considered diagnostic of pulmonary edema. EVLW index was then compared to three established bedside L-US protocols that evaluate sonographic B-lines: (1) a 28-zone protocol (total B-line score [TBS]) (2) a scanning 8-region examination, and (3) a 4-point examination. Results: Eighty-nine comparisons were obtained. A statistically significant positive correlation was found between L-US TBS and an EVLW index 10 mL/kg (r = 0.668, P < 0.001). The 28-zone protocol score 39 has a sensitivity of 81.6% and a specificity of 76.5% to define EVLW index 10 mL/kg. In contrast, the positive 4-point examination and scanning 8-regions showed low sensitivity (23.7% and 50.0%, respectively) but high specificity (96.1% and 88.2%, respectively). Ten patients with a total of 21 comparisons met criteria for acute respiratory distress syndrome (ARDS). In this subgroup, only the TBS had statistically significant positive correlation to EVLW (r = 0.488, P = 0.025). Conclusion: L-US is feasible in patients with severe sepsis. In addition, L-US 28-zone protocol demonstrated high specificity and better sensitivity than abbreviated 4-and 8-zone protocols. In ARDS, the L-US 28-zone protocol was more accurate than the 4-and 8-zone protocols in predicting EVLW. Consideration of limitations of the latter protocols may prevent clinicians from reaching premature conclusions regarding the prediction of EVLW. Trial Registration: ISRCTN11419081.