Abstract
An 84-year-old, 62kg, male with severe aortic stenosis, old myocardial infarction, and AV block (II°) was scheduled for balloon dilation for urethral stenosis. The patient had a history of Adams-Stokes disease and transient cerebral ischemic attack (TIA). The patient was received 1.5mg of diazepam intramuscularly. His blood pressure and heart rate were 160/80mmHg and 70bpm when he arrived at the operating room. After the sacral cornua were identified, a 22-gauge needle was inserted into sacral canal through the sacral hiatus in the prone position. After confirming negative aspiration for blood nor cerebrospinal fluid, 2ml of 1% lidocaine with 1: 200, 000 epinephrine was injected for a test dose. The test dose produced no signs of either systemic or subarachinoid injection. An additional 16ml of 1% lidocaine with 1: 200, 000 epinephrine was injected 2min after the injection of the test dose. Soon after the injection, the patient was placed in the supine position. Five min after the injection, the patient was developed to be drowsy, and heart rate decreased to 38bpm from 70bpm. However, there was no changes in artrial blood pressure. Ten min after the injection, he lost consciousness and became apnea. The trachea was intubated immediately and a manual ventilation was started. Blood pressure and heart rate were 128/62mmHg and 34bpm, respectively. Heart rate increased to 68bpm after the injection of 0.3mg of atropine. Spontaneous breathing appeared about 1hr after the injection of lidocaine with epinephrine. The patient recovered consciousness 2hr after the injection, and had no neurological deficits. There were no abnormal findings on the electroencephalography and the cranial CT next morning. The plasma concentrations of lidocaine showed 4.3 μg/ml and 1.6μg/ml, 15min and 2hr after the injection of lidocaine, respectively.
It was presented that the causes of apnea and loss of consciousness were due to intoxication of lidocaine. Further, we should take great care in appearances of local anesthetic intoxication when elderly patients with severe cardiac diseases undergo caudal anesthesia.
