Hidefumi Inoue

Blood concentrations of tetracaine and its metabolite following spinal anesthesia

Blood concentrations of tetracaine and its metabolite, p-butylaminobenzoic acid, were measured after spinal anesthesia with tetracaine which had been administered to patients under going orthopedic surgery. Tetracaine, an ester anesthetic, was given to 10 patients, the dose was 8-14mg, and blood samples were collected 1, 2 and 6h after the injection of tetracaine. We used gas chromatography/mass spectrometry for purposes of analysis. Tetracaine was not detected in any blood sample, but the metabolite was detected in each sample with the mean concentrations of 126.5, 97.9 and 43.3ng/ml at 1, 2 and 6h, respectively. This data will be useful in determination of the cause of death after spinal anesthesia with tetracaine.

Distribution of tetracaine and its metabolite in rabbits after high versus normal spinal anesthesia

High spinal anesthesia is one cause of sudden death associated with the spinal anesthesia. We did animal experiments to verify high spinal anesthesia by analyzing tetracaine and its metabolite, p-butylaminobenzoic acid in tissue samples. Tetracaine (0.25% in 10% glucose solution) 0.21-0.28 mg/kg was administered to two groups of rabbits to induce high and normal spinal anesthesia. Tetracaine and the metabolite in rabbit tissues were analyzed by gas chromatography-mass spectrometry, as a free base for tetracaine and as tert-butyldimethylsilyl derivative for the metabolite. In the group given high spinal anesthesia, levels of the metabolite in the brain stem were higher than in the cerebrum, cerebellum and whole blood. On the other hand, in the group given normal spinal anesthesia, the opposite results were obtained. Therefore, high spinal anesthesia induced by tetracaine can be diagnosed by comparing the concentrations of metabolite in whole blood, cerebrum, cerebellum and brain stem.

Pulmonary edema after laparoscopic adrenalectomy in a pregnant patient with Cushing's syndrome.

crinological studies were performed. Laboratory studies revealed abnormally high levels of serum cortisol (58.6 μg·dl21), urinary 17-OHCS (18mg·day21), and urinary cortisol (1860 μg·day21) and a low level of ACTH (5.5pg·ml21). Furthermore, MRI revealed a left adrenal tumor 3 cm in diameter. Cushing’s syndrome was diagnosed from these data at 28 weeks of gestation. Arterial hypoxia was not observed (PaO2 5 96mmHg, FiO2 5 0.21). Because the hypertension could not be controlled by medications (α-methyldopa and furosemide), she was scheduled for laparoscopic adrenalectomy at 31 weeks of gestation. She was premedicated with diazepam (5 mg, p.o.) and famotidine (20mg, p.o.) 4 h before anesthesia. In the operating room, an epidural catheter was placed 5 cm cephalad via the T9–10 interspace with a Tuohy needle (17 G) using the saline loss of resistance technique in the lateral position. As a test dose, 3 ml of 2% mepivacaine was injected through the epidural catheter, and no hypesthesia was observed after 10 min of injection. An additional 10ml of 2% mepivacaine was injected, and the hypesthesia level was obtained from T4 to T11 after 10min of injection. Before induction, the blood pressure was 180/100mmHg. Anesthesia was induced with 175mg thiamylal and 0.1 mg fentanyl with cricoid pressure. The patient was intubated easily with 6 mg vecuronium. After intubation, the blood pressure was 168/92 mmHg, and no secretion could be aspirated through the endotracheal tube. Anesthesia was maintained with sevoflurane (1%–3%) and epidural infusion of 2% mepivacaine (5 ml·h21). She was placed in the flexed lateral position and underwent laparoscopic adrenalectomy. The intraperitoneal pressure during laparoscopy was less than 10 mmHg. The blood pressure was almost stable (130– 170/80–100 mmHg) before isolation of the adrenal gland and changed dynamically (85–190/55–100 mmHg) during isolation of the tumor. The total operating time was two and a half hours. Pathohistological study revealed that the adrenal tumor was an adenoma. During emer

Whole body oxygen consumption during extracorporeal hepatic resection: usefulness of continuous monitoring of mixed venous oxygen saturation.

Whole body oxygen consumption was measured using a thermodilution fibreoptic catheter in two patients undergoing extracorporeal hepatic resection. Each patient had virtually normal liver function before the operation. Anaesthesia was induced and maintained in a standard fashion and a venovenous bypass instituted. The anhepatic periods were 302 and 157 min. Upon removal of the liver, the oxygen consumption decreased by about 40% (50 mL/min), while the mixed venous oxygen saturation increased by about 15%. Following re‐implantation, the oxygen consumption recovered and increased transiently above control values, while the mixed venous oxygen saturation changed in a reciprocal way. Monitoring whole body oxygen consumption instead of hepatic oxygen consumption seemed helpful in estimating restoration of blood flow and functions in the liver after reperfusion. It was also suggested that changes in oxygen consumption as well as those in cardiac output and haemoglobin concentration could be predicted easily by continuous monitoring of mixed venous oxygen saturation during the peri‐anhepatic period.

Unusual placement of a central venous catheter.

Central venous catheterization is frequently done by anesthesiologists in the operating room or in the intensive care unit. The failure rate in correctly positioning central venous lines has been reported as being between 6% and 9% [1,2]. The internal jugular vein is the most common location of a malpositioned catheter entering from the subclavian vein. Misdirection of catheters within major tributaries of the superior vena cava is also not uncommon. However, erroneous positioning in small tributaries of a large central vein is a rare occurrence. We describe a case in which catheter tip was placed in an unusual intrathoracic site. A right percutaneous subclavian catheter (Argyle 16G Nippon Sherwood, Tokyo) was placed for the route of aspiration of air emboli as well as for gaining venous access in a 52-year-old woman who was scheduled for laparoscopic cholecystectomy. After tracheal intubation under sevoflurane anesthesia, the catheter was advanced 20 cm through an infraclavicular approach without any difficulty. An anteroposterior radiograph revealed the catheter to be apparently malpositioned (Fig. 1). The catheter seemed to be extravascular and to have perforated the lung. However, easy aspiration of blood confirmed that the tip was in a vessel. Soon after, the catheter was replaced using the same sheath, and it was confirmed by a chest radiograph that the line was appropriately placed with the tip in the right atrium. The location of the malpositioned catheter was at first considered to be the left internal mammary vein or the left superior intercostal vein via the left brachiocephalic vein. However, although the straight descending portion of the line passing through the edge of the aortic