We read with great interest the article by Berg et al.1 about the evaluation of diaphragmatic excursion after interscalene nerve block with liposomal bupivacaine versus plain bupivacaine.
In their study, the authors investigated as a primary outcome the effect of liposomal bupivacaine combined with plain bupivacaine versus plain bupivacaine alone on diaphragmatic excursion during sigh (deep) and sniff (shallow) breathing in patients undergoing total shoulder arthroscopy in the immediate postoperative period and after 24 h.1
The study did not detect a difference between the two groups in absolute values of diaphragm excursion during a sigh breath at 24 h (P = 0.112), despite a greater than 1 cm difference observed. In addition, a significant difference between groups was noted in the percentage change with respect to preblock levels: –24% in the liposomal bupivacaine with bupivacaine group compared with +9% in the bupivacaine group.
The authors concluded that...