[A Problem with Flow Indicators of Anesthesia Machine].

Some anesthesia machines indicate both analog and digital flow volumes of oxygen, air and nitrous oxide. We have noticed that there are discrepancies in the flows between analog and digital flow indicators of two anesthesia machine models (Dräger ; Fabius GS premium and Fabius Tiro). When oxygen or air flow is low, the analog indicator shows higher flows than the digital indicator. In contrast, when oxygen or air flow is high, the analog indicator shows lower flows than the digital indicator. This discrepancy is comparatively small when total gas flow is within the range of 2-5 l x min(-1). We contacted the manufacturer, which replied that the digital indicator is correct and the analog indicator should be regarded as an adjunctive, in case of a power failure when the digital indicator does not function. But this discrepancy may cause practical problems. When we cannot use a digital indicator and have to perform ventilation using a supporting gas cylinder, we may misjudge the available time for oxygen. In addition, when we use only analog indicator, insufficient volume of oxygen may be delivered, leading to the grave hypoxia.

[Problems with the Structure of a New Pentax-Airwayscope S200].

BACKGROUND: Pentax-Airwayscope (AWS-S100) is useful for tracheal intubation, and a new version S200 has recently been introduced to clinical practice. We felt that S200 was more difficult than the S100 in attaching and detaching a single-use Introck blade. METHODS: In a randomized cross-over design, we compared S100 and S200, for the ease of attaching to and detaching from the Introck, fixation of the Introck using the fixation ring of the main body, and insertion time. RESULTS: Compared with S100, it was easier for S200 to fix the Introck using the fixation ring (78% vs 72%) (P < 0.05), but it was more difficult for S200 to attach (the incidence 43% vs 2%) and detach (53% vs 11%) the Introck (both P < 0.001). Insertion time was also significantly longer for S200 than S100 (median 9 [IQR : 6-19] s vs 4 [IQR : 3-6] s) (P < 0.001). The flexible scope of one of two S200s kinked and was broken during attachment. CONCLUSIONS: It is necessary to apply lubricant to the distal part of the scope to prevent damage to the scope.

[Anesthetic management of a patient with aortocaval fistula caused by rupture of a huge abdominal aortic aneurysm into the inferior vena cava].

Aortocaval fistula is a rare complication of ruptured abdominal aortic aneurysm. We report anesthetic management of a patient with aortocaval fistula caused by rupture of a huge abdominal aortic aneurysm into the inferior vena cava. A 51-year-old man who had complained of low back pain and general fatigue was referred to our hospital because of his liver damage. Aortocaval fistula due to rupture of a huge abdominal aortic aneurysm was diagnosed from physical examination, enhanced computed tomography and color Doppler ultrasonography. Anesthesia was induced with propofol and rocuronium, and was maintained with sevoflurane and remifentanil. After induction of anesthesia, the central venous pressure and cardiac index showed remarkably high values because of arteriovenous shunt. When the aneurysm was incised after the clamping of the abdominal aorta, massive venous bleeding occurred from the fistula and caused severe hypotension. Blood pressure recovered by digital compression of the bleeding point and the use of an autotransfusion device. After the repair of the aortocaval fistula, the hemodynamics became stable. The patient had a high output but a good cardiac function in preoperative examination. Therefore anesthesia was managed successfully without worsening high-output heart failure.

[Anesthetic management of a hemodialysis-dependent patient implanted with a CRT-D device undergoing an operation for perforated peritonitis].

A 53-year-old man was admitted to our hospital for hematochezia, and an emergency operation was scheduled for his perforated sigmoid colon. He had received a CRT-D (cardiac resynchronization therapy with defibrillator) device for dilated cardiomyopathy two years before and had been receiving hemodialysis for the past year. Anesthesia was induced with midazolam and remifentanil and maintained with remifentanil and sevoflurane in oxygen. Before surgery, we disabled the defibrillation function of the CRT-D device and changed its pacing mode from VVI to VOO, and electrodes of an external defibrillator were attached to the chest wall. Dopamine and norepinephrine were administered via a central venous catheter, and systolic blood pressure was maintained between 70 and 80 mmHg and CVP between 8 and 13 mmHg. Sigmoidectomy was performed and he was transferred to the ICU intubated. Although intensive care procedures, such as mechanical ventilation, continuous hemodiafiltration, and direct hemoperfusion with polymyxin B-immobilized fibers were performed, he died of multiple organ failure on postoperative day 48. CRT-D has become mainstream cardiac resynchronization therapy and will require attention for anesthetic management of patients implanted with the CRT-D device.