The changes in cases and methods of general anesthesia for oral and maxillofacial surgery or dental treatment during a recent nine year period at Okayama University Dental Hospital

We evaluated the changes in cases and methods of general anesthesia for oral and maxillofacial surgery or dental treatment during a recent nine year period (April 1987-March 1995) at Okayama University Dental Hospital, dividing the 9 years into three periods and making statistical analyses using a l 0x m contingency table and chi-square test for independence. There were no significant changes in age distribution or diagnosis during these recent 9 years (Table 1, 2). There was a significant change in the method of induction of anesthesia (Table 3). Modified-neurolept anesthesia was performed on the most patients from 1987 to 1989, while slow induction with sevoflurane or isoflurane has been generally used since 1990. Nasotracheal intubation tended to increase in comparison with orotracheal intubation (Table 4). A significant change was found in the method of maintenance of anesthesia with the same tendency as that of induction of anesthesia (Table 5). There was no significant change in the duration of anesthesia (Table 6), but there was a significant change in blood loss during operations. Cases with large volumes of blood loss have tended to decrease in these recent 9 years (Table 7). Some preoperative complications such as abnormal liver, respiratory function without asthma, and central nervous system disease have significantly increased (Table 8). Furthermore, cases with preanesthetic ASA Risk 2 or 3 have tended to increase (Table 9). There were significant changes in some intraoperative complications such as abnormal ECG, inadequate urine output, and abnormal body temperature, but they showed no consistent tendencies (Table 10). The were significant changes in some postoperative complications such as fever, shivering and respiratory complications, which tended to decrease in this period (Table 11). The increase in preoperative complications was thought to be due to social changes including the increase in elderly population. Furthermore, it seems that advance in anesthetics and method of general anesthesia.