**11. Points of concern and disadvantages associated with performing regional anesthesia with general anesthesia**

When using epidural anesthesia in combination with general anesthesia, it is highly recom‐ mended to insert the epidural catheter and then inject a test dose of the local anesthetic solu‐ tion prior to the anesthesia induction, as this sequence allows for early recognition of severe complications, such as intrathecal or intravascular injection of the local anesthetic agent, or nerve injury caused by the epidural needle. In other recent cases when regional anesthesia was used, some anesthesiologists employed an ultrasound technique following anesthesia induction. With ultrasound imaging, the positions of the block needle, nerves, and blood ves‐ sels, as well as spread of the local anesthetic solution when performing regional anesthesia are clearly and accurately shown, thus ensuring the safety of the procedure even under an anes‐ thetized condition in which the patient is unconscious. Nevertheless, there is no doubt that accidental nerve injury, as well as intravascular or unintended injection of the local anesthetic solution remain major threats for safety in all cases, which must be noted when performing regional anesthesia.

In a review conducted by the Japanese Society of Anesthesiologists of cases treated at certi‐ fied training hospitals in Japan between 1999 and 2001, a higher incidence of intraoperative coronary ischemia was found in laparotomy patients anesthetized by inhalation general anes‐ thesia in combination with regional anesthesia as compared to those who received general anesthesia alone [29]. Those findings indicated the possibility that a combined regional and general anesthesia technique might be unsuitable for patients with severe coronary diseases. On the other hand, TAPB and RSB techniques for a laparotomy have only been widely uti‐ lized in the most recent decade, thus it is reasonable to assume that cases of regional anes‐ thesia included in that report were mainly epidural anesthesia. The combination of epidural anesthesia with general anesthesia can sometimes induce severe hypotension, which might have induced coronary ischemia in those patients. Furthermore, hypotensive effects might be more critical in patients with low output syndrome. However, as shown in our study of general anesthesia with TAPB, a peripheral nerve block does not usually induce hypoten‐ sion, because it has a limited effect on the sympathetic nervous system as compared with epidural anesthesia. Thus, as long as an appropriate regional anesthesia method is carefully chosen, combined regional and general anesthesia should not be contraindicated in patients with severe coronary disease or low ejection fraction, though special caution is required for management of such high‐risk patients.
