CHANGES IN PERMEABILITY OF SHEEPS LUNGS BY OLEIC-ACID ARE DOSE-DEPENDENT

Objective: To evaluate a two-isotope technique to detect graded change s in pulmonary microvascular permeability. Design: Open experimental s tudy. Setting: University hospital, Sweden. Material: Fifty-seven shee p. Interventions: Catherisation of one carotid artery, pulmonary arter y and central vein. Control group 1 (n = 10), control group 2 (n = 12) had an additional pulmonary artery balloon catheter inserted, experim ental group 3 (n = 9) was given oleic acid 0.005 mg kg(-1) BW, experim ental group 4 (n = 12) received oleic acid 0.02 mg kg(-1) BW and exper imental group 5 (n = 11) 0.05 mg kg(-1) BW. Groups 3-5 had all PA cath eters. All animals were intubated and ventilated artificially. Duratio n of experiments was 6 hours. Outcome measures: Transferrin was labell ed in vivo with In-113m chloride and erythrocytes with Tc-99m followin g injection of stannous chloride. External gamma counting was correcte d for background, decay and scatter. Blood activity was used as refere nce. Normalised slope index (NSI) and transferrin leak index (TLI) wer e calculated as measures of pulmonary microvascular permeability. Resu lts: A graded response in both NSI and TLI was found. Insertion of the PA catheter (group 2) significantly increased NSI from (group 1) (1.4 (0.1)) 10(-4) min(-1) to (11 (2)) 10(-4) min(-1) (p < 0.05). TLI incr eased significantly from (9 (2)) 10(-4) min(-1) to (72 (13)) 10(-4) mi n(-1). Oleic acid increased NSI significantly to (13 (1)) 10(-4) min(- 1), (32 (2)) 10(-4) min(-1) and (61 (5)) 10(-4) min(-1) in groups 3-5, respectively. Corresponding values for TLI were (95 (13)) 10(-4) min( -1), (162 (6)) 10(-4) min(-1) and (228 (26)) 10(-4) min(-1), respectiv ely. Conclusion: The double-isotope technique of external monitoring o f permeability changes to protein in the lungs was sensitive to pick u p graded increments in leakage, related in a dose-dependent way to lun g injury.