Superior vena cava

Central venous (superior vena cava) or mixed venous oxygen saturation >70%... 

The primary goal of treatment of superior vena cava (SVC) syndrome is to relieve obstruction of the superior vena cava by treating the underlying malignancy. 

The superior vena cava (SVC) is the primary drainage vein for blood return from the head, neck, and upper extremities. It is a relatively thin-walled vein that is particularly vulnerable to obstruction from adjacent tumor invasion or thrombosis. The obstruction leads to elevated venous pressure, although collateral veins partially compensate. This is one reason for the relatively slow onset of the classic symptoms of SVCS. In fact, 75% of patients have signs and symptoms for more than 1 week before seeking medical attention.15... 

TABLE 96-6. Tumors Most Commonly Associated with Superior Vena Cava Syndrome... 

Wudel LJ, Nesbitt JC. Superior vena cava syndrome. Curr Treat Options Oncol 2001 2 77-91. 

PN can be administered via a smaller peripheral vein (e.g., cephalic or basilic vein) or via a larger central vein (e.g., superior vena cava). Peripheral PN (PPN) is infused via a peripheral vein and generally is reserved for short-term administration (up to 7 days) when central venous access is not available. PN formulations are hypertonic, and infusion via a peripheral vein can cause thrombophlebitis. Factors that increase the risk of phlebitis include high solution osmolarity, extreme pH, rapid infusion rate, vein properties, catheter material, and infusion time via the same vein.20 The osmolarity of PPN admixtures should be limited to 900 mOsm/L or less to minimize the risk of phlebitis. The approximate osmolarity of a PN admixture can be calculated from the osmolarities of individual components ... 

SVC Superior vena cava VSS Vital signs stable... 

The sinoatrial (SA) node is located in the wall of the right atrium near the entrance of the superior vena cava. The specialized cells of the SA node spontaneously depolarize to threshold and generate 70 to 75 heart beats/ min. The "resting" membrane potential, or pacemaker potential, is different from that of neurons, which were discussed in Chapter 3 (Membrane Potential). First of all, this potential is approximately -55 mV, which is less negative than that found in neurons (-70 mV see Figure 13.2, panel A). Second, pacemaker potential is unstable and slowly depolarizes toward threshold (phase 4). Two important ion currents contribute to this slow depolarization. These cells are inherently leaky to sodium. The resulting influx of Na+ ions occurs through channels that differ from the fast Na+ channels that cause rapid depolarization in other types of excitable cells. Toward the end of phase... 

Suggested Alternatives for Differential Diagnosis Abdominal aneurysm, aortic dissection, pleural effusion, subarachnoid hemorrhage, superior vena cava syndrome, hantavirus pulmonary syndrome, mediastinitis, fulminate mediastinal tumors pneumonia, gastroenteritis, meningitis, ecthyma, rat bite fever, spider bite, leprosy, plague, tularemia, coccidioidomycosis, diphtheria, glanders, histoplasmosis, psittacosis, typhoid fever, and rickettsial pox. 

Superionic conducting glass systems, 12 586 Superior vena cava, 5 80 Super iron cells, 3 431t Superlattice(s), 13 499, 19 166 via MOCVD, 22 158-160 Superleaks, 17 354 Super Lewis acids, 12 191 Superluminscent LEDs, 22 176 Supermilling acid dyes, 26 396 Super milling dyes, 9 184, 185 Super-moire pattern, 17 428 Supermolecular organization, of polyamide fibers, 19 740... 

Hershey CO, McVeigh RC, Miller RP. Transient superior vena cava syndrome due to propylthiouracil therapy in intrathoracic goiter. Chest 1981 79(3) 356-7. 

The sinoatrial node (SA), consisting of spindle-shaped cells, initiates the electrical activity of the heart. From its location in the right atrium in proximity to the superior vena cava, the electrical activity spreads to the atria whose cells are larger than those of the SA. The pulse from the atria spreads to the atrioventricular node (AV), the gateway to the ventricles. The atria and the ventricles are electrically isolated. The AV node also slows down the electrical activity giving the atria time to fill. The bundle of His is the upper end of the electrical path, which through the Purkinje fibers allows the electrical signal to activate the ventricles and thus to pump the blood. 

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