We read with expectations the study “Lung Ultrasound Score on Postoperative Day 1 Is Predictive of the Occurrence of Pulmonary Complications after Major Abdominal Surgery: A Multicenter Prospective Observational Study” by Boussier et al.  We congratulate the authors for this very interesting study of a frequent complication that can be predicted by a simple tool: lung ultrasound.

However, we would like to point out that this work is not the first to have investigated the association between lung ultrasound and pulmonary complications after major abdominal surgery. Indeed, we previously published an observational study in which secondary objective was to study the relationship between the final Delta-B-line and the appearance of postoperative pulmonary complications on day 14. This final Delta-B-line was calculated as the number of B-lines at the end of the intervention minus the number of B-lines at baseline. The number of B-lines was counted at four bilateral predefined points (right anterior and lateral, and left anterior and lateral), as previously described.  This anterolateral analysis, as in the case of the publication by Boussier et al., eliminates the need to reposition the patient for posterior image acquisition. The final Delta-B-line was significantly higher for patients with pulmonary complications than those without (median [interquartile range], 7 [5 to 12] vs. 4 [2 to 7]; P < 0.01). The final Delta-B-line was able to predict postoperative pulmonary complications with an area under the curve of 0.74 (95% CI, 0.67 to 0.80; P < 0.01). The best threshold was five for the final Delta-B-line (sensitivity of 0.80, specificity of 0.57, positive likelihood ratio of 1.86, and negative likelihood ratio of 0.35).

The advantages of our method are numerous. Acquiring and counting only B lines at 4 points is simpler than using the lung ultrasound score, although it is not recommended and is not the subject of any consensus.  The fact that we measured the final Delta-B-line directly at the end of the surgery gives us an even earlier indication of the occurrence of postoperative complications. Finally, the predictive capacity of our method is better than the lung ultrasound score on day 1. 

Given the ease of use of ultrasound in operating theaters today, we would suggest combining the two approaches: perform a simple B-line count at the four anterolateral predefined points at the end of the surgery and, if this count is greater than five, complete the analysis with a more detailed lung ultrasound score at postoperative day 1. In the “Editor’s Perspective” section of the Boussier et al. study, we read that the predictive value of the lung ultrasound score on day 1 still needs to be improved, and we think that the combination of these two approaches could help to improve this.

Anesthesiologists must seize the full potential of the ultrasound equipment available to them to prevent postoperative complications now.