Aerosolized surfactant and dextran for experimental acute respiratory distress syndrome caused by acidified milk in rats.
BACKGROUND
Inhibition of pulmonary surfactant by plasma-derived proteins is an important pathogenetic factor of acute respiratory distress syndrome (ARDS). Inhalation of aerosolized surfactant may be suitable for early treatment of ARDS. However, requirement of a high dose is a drawback. Because dextran reverses surfactant inhibition, we examined whether dextran improves the therapeutic effects of aerosolized surfactant in rats with experimental ARDS.


METHODS
Acidified milk (pH 1.8, 1.5 ml kg(-1)) was injected into the trachea of the rats ventilated with pure oxygen using 2.45 kPa peak inspiratory pressure and 0.74 kPa positive end-expiratory pressure. When PaO2 decreased to <13 kPa, the rats were assigned to four groups: control group (n = 8), receiving no material; D-only group (n = 6), receiving aerosolized dextran for 45 min; S-only group (n = 8), receiving aerosolized modified natural surfactant (MNS) for 30 min; and S-plus-D group (n = 9), receiving aerosolized MNS for 30 min followed by aerosolized dextran for 15 min.


RESULTS
In the control group and D-only groups, the mean PaO2 remained at <10 kPa for 180 min. In the S-only and S-plus-D groups, the PaO2 increased to 50 kPa (P < 0.01 vs. untreated). The PaO2 of the surfactant-only group gradually decreased to <17 kPa at 180 min, whereas the PaO2 of the S-plus-D group was maintained at >38 kPa for 180 min (P < 0.01 vs. S-only group).


CONCLUSIONS
Inhalation of aerosolized dextran potentiates the effects of aerosolized surfactant by prolonging the therapeutic response.
Cui
X G
XG
Department of Anesthesiology and Intensive Care Medicine, Graduate School of Medical Science, Kanazawa University, Kanazawa, Japan.
Tashiro
K
K
Matsumoto
H
H
Tsubokawa
Y
Y
Kobayashi
T
T
D000336:Aerosols; D000704:Analysis of Variance; D000818:Animals; D000925:Anticoagulants / Q000627:therapeutic use*; D003911:Dextrans / Q000627:therapeutic use*; D004195:Disease Models, Animal; D019570:Inhalation Exposure / Q000009:adverse effects; D008297:Male; D008892:Milk / Q000009:adverse effects / Q000737:chemistry; D010100:Oxygen / Q000008:administration & dosage; D011663:Pulmonary Surfactants / Q000008:administration & dosage / Q000627:therapeutic use*; D051381:Rats; D017208:Rats, Wistar; D012121:Respiration, Artificial; D012128:Respiratory Distress Syndrome / Q000139:chemically induced / Q000188:drug therapy* / Q000473:pathology; D012129:Respiratory Function Tests; D013997:Time Factors
D000336:Aerosols; D000925:Anticoagulants; D003911:Dextrans; D011663:Pulmonary Surfactants; D010100:Oxygen