[The in vitro model of inhalation anesthesia using rodent ventilator]

To set up a method of applying inhalation anesthesia in rodent using rodent ventilator and to study the dynamic procedure of the in vitro model.

The output port of the anesthesia machine was connected to the input port of the rodent ventilator, which was connected to a syringe simulating the lung. After supply of anesthetic gas, the gas samples from the input port of the ventilator and the syringe in the end-expiratory phase were collected at 10, 20, 30, 40, 50, 60, 90, 120, 180, 300, 600 and 900 seconds respectively and were determined using the gas chromatography(GC). The ratios of the anesthetic concentrations of the syringe to that of the input port were calculated (CE/CI). In elimination phase, the gas samples from the syringe were collected at 0,10, 20, 30, 40, 50, 60, 90, 120, 180, 300, 600 and 900 seconds respectively and were determined by GC. The ratios of the anesthetic concentrations of the gas at 10, 20, 30, 40, 50, 60, 90, 120, 180, 300, 600 and 900 seconds to that at 0 second were calculated(C'E/C0).

CE/CI increased in the inhalation phase, there was an inverse relationship between CE/CI and time, the correlation coefficients were 0.90, 0.95 and 0.93 respectively (P < 0.01). The mathematical fitting equations were y = -0.19 + 0.19x(-1), y = -7.75 + 0.99x(-1), and y = -7.21 + 0.97x(-1) respectively. C'E/C0 decreased in the elimination phase,the correlation coefficients were 0.90, 0.94 and 0.95 respectively (P < 0.01). The mathematic fitting eqations were y = 5.65-0.02x(-1), y = 7.82-0.01x(-1),and y = 8.20-0.01x(-1), respectively.

The in vitro model of rodent inhalation anesthesia using the rodent ventilator was set up. The establishment of this model has provided a basis for studies on inhalation anesthesia in rodents.