Temporary extracorporeal axillofemoral venous bypass--a beneficial device in operation for superior vena caval syndrome due to intrathoracic malignancies

Life-threatening complications can occur unexpectedly during general anesthesia in operations for superior vena caval (SVC) syndrome due to intrathoracic tumors. To prevent such sequelae, we have placed a temporary extracorporeal axillofemoral venous bypass graft with satisfactory results. In six patients (malignant mediastinal tumor, four; lung cancer, two), under local anesthesia before induction of general one, the cannulas, each appropriately sized in accordance with the diameter of the axillary and femoral veins, were directly introduced into the corresponding veins after systemic heparinization. The two cannulas were connected with a tube to which a side arm, which was usually clamped, was connected. The venous pressure of the internal jugular vein decreased immediately after establishment of the temporary bypass in all patients. The symptoms that accompanied SVC syndrome did not worsen and the life-threatening complications at the time of induction of general anesthesia were avoided with this procedure. In each case cardiopulmonary bypass on stand-by was unnecessary at this time. Venous bypass grafting with vascular prostheses were mainly performed under cardiopulmonary bypass, which was required for such operative procedures. In three patients the side arms were used for part of the venous drainage during cardiopulmonary bypass. The SVC syndrome instantly disappeared after operations in all patients including one in hospital death. No serious complications related to the temporary bypass procedure have been observed. This temporary bypass procedure has several advantages. It can be safely performed under local anesthesia with no special technique for the cannulation. Venous blood naturally drains from the upper part to the lower part of the body by pressure gradient, that warrants the safe induction of general anesthesia and ensuing operative procedures. The side arm is available for venous drainage during cardiopulmonary bypass. There are no serious complications related to the bypass procedure. Thus this temporary bypass is recommended as a life-saving and auxiliary device in urgent operations for acute progressive SVC syndrome with symptoms of cerebral edema and upper airway obstruction due to intrathoracic malignancies.     

A picture archiving and communication system module for radiology

This paper presents the design and implementation of a clinical picture archiving and communication system (PACS) module within the radiology department of a 700-bed teaching hospital. The system is composed of an integrated network of digital devices used to electronically acquire, store, manage, and display radiological text and image information. Operationally the system behaves as a large queueing network allowing processes to operate concurrently in a coordinated and prioritized fashion. Secondary reviews (radiology conferences and fast case reviews by clinicians) are being conducted from a 512 X 512 CRT viewing station. Preliminary evaluation based on formal survey and usage statistics shows that the system is rapidly being accepted by radiologists and clinicians for the review and processing of digital radiographic images.     

Composite valve graft replacement in patients with type A aortic dissection--a modified cabrol procedure

Composite valve graft replacement of the ascending aorta and aortic valve is indicated for a variety of conditions affecting the aortic root. However, a major drawback in this operation is bleeding from the proximal suture line and coronary anastomosis especially in patient with friable root tissue involved by aortic dissection. We describe here a modified technique to take advantage of the aortic button and cabrol techniques to reattach the coronary artery ostia. We have experienced seven patients with the aortic root replacements for type A dissection using the described technique over the past two years. In view of our favorable experience, we recommend this technique especially for patient with acute dissection involving nondilated aortic annulus, in addition to the patients with Marfan syndrome or annulo-aortic ectasia.     

Tracking error of phased array antenna

The tracking error of a phased array antenna between transmitting and receiving frequencies was measured by in-flight experiments using a geostationary satellite. The tracking error was found to depend on beam-scanning angle and the ratio of transmitting and receiving frequencies. Measured results agreed well with a theoretical prediction. An effective method to eliminate the tracking error is proposed     

Two cases of parafilariasis in dairy cattle and treatment of hemorrhage with levamisole topical application

On June and August in 1989, cutaneous hemorrhagic parafilariasis was found in two cattle among 30 pregnant dairy cattle transported from Hokkaido to Chiba Prefecture. One adult female worm each was recovered from the blood spot in both cattle. Ivermectin oral administration, dosage rate of 200 micrograms/kg body weight, had no effect on the occurrence of the blood spots. Topical application of levamisole on a blood spot at a 2.5% concentration showed to stop the bleeding within a few minutes after treatment. This method was very easy to use at the farm situation where cutaneous hemorrhagic parafilariasis sporadically occurred. The disease has not been found in Chiba Prefecture on a whole since those cases in 1989.     

Multi-organ ischemia due to traumatic lesion of the descending thoracic aorta--a case-report

This is a case of severe ischemic and reperfusion multi-organ failure due to descending thoracic aortic rupture. A 25 year-old man received a hard blow on his chest in a traffic accident. Chest X-ray, CT scans and aortogram elucidated descending thoracic aortic rupture. Emergency operation was performed 18 hours after the injury. The aortic rupture, 4/5 of the aortic circumference with intact adventitia was seen. The descending aorta 22 distal to the left subclavian artery was repaired under cardio-pulmonary bypass with selective cerebral perfusion. Ischemia due to aortic occlusion with thrombus and reperfusion injury after reconstruction of the aorta connected with rhabdmyolysis and severe multi-organ failure. Intestinal necrosis required laparotomy on the 9th and 15th post operative day. The patient died on 15th postoperative day of multi-organ failure.     

Efficient laser emission in concentrated Nd laser materials underpumping into the emitting level

The possibility of using concentrated Nd laser materials for efficient laser emission and for scaling to high powers is discussed. It is shown that the increased optical absorption in these materials makes direct pumping into the emitting level feasible, with a reduction of the quantum defect between the pump and emission wavelengths, which in turn can enhance the laser emission characteristics and reduce heat generation under pumping. The investigation of the effect of Nd concentration on emission decay of Nd:YAG indicates that up to quite high concentrations, the reduction of the emission quantum efficiency by self-quenching can be compensated by an increase in the pump absorption. Efficient continuous-wave laser emission is demonstrated under direct pumping into the ⁴F_3/2 emitting level of Nd:YAG crystals with up to 3.5-at.% Nd, Nd:YAG ceramics with up to 6.8-at.% Nd, and Nd:YVO₄ crystals with up to 3-at.% Nd. Superior performance as compared to traditional pumping into the ⁴F _5/2 state were obtained. It is inferred that direct pumping into the emitting level of concentrated Nd materials can improve the efficiency of solid-state lasers in the free-generation or low-storage regimes and opens the possibility of scaling these lasers to high powers     

Highly flat super-continuum generation from 2 ps pulses using 1 km-long erbium-doped fibre amplifier

A method for generating a supercontinuum (SC) that uses a long optical fibre amplifier is proposed. In this method, the distributed optical gain and the long interaction length enable one to generate the flat SC generation from picosecond pulses used in telecommunication systems. Flat SC generation over 34 nm from a 2 ps pulse train using a 1 km-long erbium-doped fibre is experimentally demonstrated.     

Effect of small openings on strength and stiffness of shear walls in reactor buildings

A total of 26 wall specimens were tested to examine the effect of small openings on the strength and stiffness of shear walls in reactor buildings. The parameters tested were the shape, number and local arrangement of the openings, and the reinforcing method around the openings. Reversed cyclic loads were applied to the specimens, and their strengths and restoring force characteristics were compared with each other to understand the effects of these parameters. Based on the test results, two methods for predicting the shear strength of walls with numerous small openings are examined. One is a method to calculate directly the strength along assumed failure lines, and the other method allows estimation of the strength reduction factors for design, taking account of the effect of openings. Both methods are found to be useful to estimate roughly the strength of such shear walls. It is also shown that the stiffness of such walls could be evaluated using a combined multi-spring model. For the reinforcing methods around openings, a simplified reinforcing method is proposed and the effectiveness of the method is discussed by checking the contribution of the reinforcement to the wall strength.