Nitric oxide donors attenuate increase in pressure drop across membrane oxygenators

We have evaluated the effect of nitric oxide (NO) on the pressure drop acro ss a membrane oxygenator in one in vitro model and two in vivo models (usin g four dogs and five pigs). In all the experiments sodium nitroprusside (SN P) was used as a NO source, whereas gaseous NO was only used in the in vitr o model. The drugs were given when the pressure drop or resistance across t he device increased to at least twice the baseline values. in the in vitro model, both SNP and gaseous NO decreased the pressure drop to 75% of its pe ak Value after 10 min and to 67% after 20 min. In the dog model, resistance decreased from 390 to 153 mmHg/l/min after 5 min and to 85 mmHg/l/min afte r 20 min for a baseline Value of 75 mmHg/l/min. The initial resistance acro ss the membrane oxygenator in the pig model increased from 6.6 +/- 1.3 to 7 4 +/- 38 mmHg/l/min. An infusion of 10 mu g/kg/min SNP reduced the resistan ce to 16 +/- 5 mmHg/l/min.