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[The effect of cervical gas insufflation on metabolic and hemodynamic during endoscopic neck surgery].

OBJECTIVE
Carbon dioxide and helium were insufflated into the neck of rabbits to investigate the effect of different levels of insufflation pressure and duration on metabolic and hemodynamic changes.


METHOD
Fifteen New Zealand rabbits were randomly divided into 5 groups: 5 mmHg CO2, 10 mmHg CO2, 15 mmHg CO2, 15 mmHg He and 0 mmHg. Arterial partial pressure of CO2 (PaCO2), pH, heart rate (HR), mean arterial pressure (MAP) and central venous pressure (CVP) were measured at baseline, 45 min and 90 min after gas insufflation and 30 min after desufflation.


RESULT
Insufflation of CO2 at 5 mmHg had not any significant effect on the parameters. PaCO2 increased significantly 45 min and 90 min after CO2 insufflation at 10 mmHg (P < 0.05). Marked changes in PaCO2, pH and CVP occurred 45 min and 90 min after CO2 insufflation at 15 mmHg (P < 0.05), and the parameters did not return to baseline 30 min after desufflation. In animals receiving He insufflation at 15 mmHg, CVP increased significantly after 90 min (P < 0.05), and the parameters returned to baseline 30 min after desufflation. Animals receiving He insufflation did not experience hypercapnia. No significant changes in HR and MAP occurred in all animals.


CONCLUSION
Carbon dioxide insufflation for endoscopic neck surgery is safe below 10 mmHg. When higher pressure is required, the level lower than 15 mmHg is recommended and the insufflation duration should be limited. The use of He should be careful due to the low solubility.