In: Health17 Sep 2009
This experiment was performed using the handling regulations of experimental animals at Aichi-Gakuin University. Ten adult beagles weighing 11.0 ± 1.7 kg were used for a study group and another 10 beagles weighing 10.7 ± 1.9 kg for a control group. Anesthesia was induced with thiamylal and succinylcholine chloride intravenously and maintained by the semiclosed circuit after intubation. Ventilation was controlled with nitrous ox-ide-oxygen-isoflurane (1%) and vecuronium. The tidal volume was adjusted to 150-200 mL based on weight, and PetC02 was maintained at 32-40 torr.
After the induction of anesthesia, an IV access route was established in an upper limb. Left and right femoral artery cannulations were performed percutaneously to measure blood pressure on one side and to collect blood from the other side. After finishing this preparation, the dog was allowed to equilibrate for more than 30 minutes to obtain stability of the circulatory system. Then, 0.4 mL (400 |xg) of 1 mg/mL of epinephrine for the study group and 0.4 mL of physiological saline for the control group was placed into an emptied dental cartridge and administered to the nasal septum mucosa via a needleless injector.
Figure 1. The injection surface of a needleless injector is placed in close contact with the nasal septum surface. Simultaneously, the septum is pressed from the opposite nasal foramen with a finger so the injection pressure on the mucosa does not escape.
The injection surface of a needleless injector (SyriJet, Mizzy, Cherry Hill, NJ) was placed in close contact with the nasal septum surface 2.5 cm away from the apex of the nose. Simultaneously, the nasal septum was pressed from the opposite nasal foramen with a finger, and then epinephrine was injected so that the injection pressure on the mucosa did not escape (Figure 1). The maximum injection volume of the SyriJet is 0.2 mL, so we immediately injected again to attain the 0.4-mL volume, for a total of 2 injections.
For the measurement of the circulatory system of both groups, systolic *blood pressure, diastolic pressure, and heart rate were recorded just before injection and 15, 30, 60, 90, 120, 180, and 300 seconds after injection. In 6 dogs from the study group, 4 mL of blood was collected from the artery to measure catecholamines simultaneously with the recording of the circulatory parameters. The collected blood was cooled and centrifuged as promptly as possible, and the blood plasma was preserved at -40°C until the measurement. A respirator (SN-480-3, Shinano, Tokyo, Japan), an OIR-7101 (Nihon Koden Corp, Tokyo, Japan) to measure PetC02, the Life Scope 8 (Nihon Koden Corp, Tokyo, Japan) to measure the circulatory system, the SyriJet injector, and high-performance liquid chromatography to measure catecholamines were used.
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