Figure 2. Pulmonary first-pass retention of rocuronium, vecuronium, Org 9487, Org 7617, and d-tubocurarine. Retention is the percentage of the administered dose of the muscle relaxant that is retained in the lungs. Time zero is the time of first appearance of indocyanin green in arterial plasma. Time 13.2 s is the average time at which 95% of indocyanin green had passed (median [range]).