Intravascular oxygenator

Wu Y, Rojas AP, Griffith GW, Skrzypchak AM, Lafayette N, Bartlett RH, Meyerhoff ME. Improving blood compatibility of intravascular oxygen sensors via catalytic decomposition of 5-nitrosothiols to generate nitric oxide in situ. Sensors and Actuators B 2007, 121, 36—46. 

Frost MC, Rudich SM> Zhang H, Marashio MA, Meyerhoff ME, In vivo biocompatibility and analytical performance of intravascular oxygen sensors prepared with improved nitric oxide-releasing silicone rubber coating. Ana Chem 2002 74 5942-7. 

Conrad, S.A., Bagley, A., Bagley, B., and Schaap, R.N. 1994. Major findings from the clinical trials of the intravascular oxygenator. Artif Organs 18(ll) 846-63. 

Cox, C.S., Zwischenberger, J.B., Traber, L.D., Traber, D.L., and Herndon, D.N. 1991. Use of an intravascular oxygenator/carbon dioxide removal device in an ovine smoke inhalation injury model. ASAIO Tram. 37(3) M411-13. 

Perfluoroalkylated fatty acid 6-esters of sucrose and aa-trehalose were prepared by a reaction of sucrose or a,a-trehalose with a perfluoroalkylated acid, Rf(CH2)rtCOOH (Rf = C4F9, C6F 3, or CgFi7, n = 2, 4, 10) in the presence of triphenylphosphine and diisopropyl azodicarboxylate in j/V,iV-dimethylformamide [262]. The surfactants were used to prepare fluorochemical emulsions intended as intravascular oxygen carriers (see Section 10.4). 

Self-propelling aerosols of antiallergic, antibiotic, antitussive, or antianginal activities have been prepared using a fluorinated surfactant as the dispersant in Freon 114 and Freon 12 [203]. As an example, epinephrine bitartrate has been dispersed with perfluoro-n-octyl- -ethylsulfonamidoethyl phosphate. The use of fluorinated surfactants in intravascular oxygen carriers and blood substitutes is discussed in Chapter 10. 

I am indebted for valuable comments and suggestions to Du Pont chemists who read the chapters in which they have expertise Drs. J. E. Dowd, T. A. Liss, and J. F. Neumer (synthesis), K. S. Prowse (applications), M. W. Duch (ESCA), J. T. Cronin (IR), A. Foris (NMR), J. R. Valentine (MS), B. E. Baker (toxicology), R. C. Bergman and S. Raynolds (intravascular oxygen carriers). I am also grateful to my son Erik H. Kissa, M.D., for reviewing the chapter on blood substitutes. 

Hypovolemic shock occurs as a consequence of inadequate intravascular volume to meet the oxygen and metabolic needs of the body. 

Therapeutic intravenous (TV) fluids include crystalloid solutions, colloidal solutions, and oxygen-carrying resuscitation solutions. Crystalloids are composed of water and electrolytes, all of which pass freely through semipermeable membranes and remain in the intravascular space for shorter periods of time. As such, these solutions are very useful for correcting electrolyte imbalances but result in smaller hemodynamic changes for a given unit of volume. 

In the early phase of serious intraabdominal infections, attention should be given to preserving major organ system function. With generalized peritonitis, large volumes of intravenous (IV) fluids are required to maintain intravascular volume, to improve cardiovascular function, and to ensure adequate tissue perfusion and oxygenation. Adequate urine output should be maintained to ensure appropriate fluid resuscitation and to preserve renal function. A common cause of early death is hypovolemic shock caused by inadequate intravascular volume expansion and tissue perfusion. 

Other optodes have been developed and tested in-vivo, all of them using a fluorophore, the fluorescence of which is quenched by oxygen. In the intravascular sensor developed by CDI, previously described, a specially synthesised fluorophore, a modified decacyclene ( Lexc=385 nm, em=515 nm), is combined with a second reference-fluorophore that is insensitive to oxygen, and is incorporated into a hydrophobic silicon membrane that is permeable to oxygen. 

The challenges encountered when developing a PFC-based oxygen carrier are very different from those of the hemoglobin-based products. They concern both the PFC itself and its formulation into a stable, biocompatible emulsion, allowing intravascular administration. 

C.E. Lundgren, G.W. Bergoe, I.Tyssebotn, The theory and application of intravascular microbubbles as an ultra-effective means of transporting oxygen and other gases. Undersea Hyperb. Med. 31 (2004) 105-106. 

M. C. Frost, S. M. Rudich, H. Zhang, M. A. Maraschio, and M. E. Meyerhoff, In Vivo Biocompatibility and Analytical Performance of Intravascular Amperometric Oxygen Sensors Prepared with Improved Nitric Oxide-Releasing Silicone Rubber Coating, Anal. Chem. 2002, 74, 5942. 

Thrombus versus embolus A clot that adheres to a vessel wall is called a thrombus, whereas an intravascular clot that floats within the blood is termed an embolus. Thus, a detached thrombus becomes an embolus. Both thrombi and emboli are dangerous, because they may occlude blood vessels and deprive tissues of oxygen and nutrients. Arterial thrombosis most often involves medium-sized vessels rendered thrombogenic by surface lesions of endothelial cells caused by atherosclerosis. In contrast, venous thrombosis is triggered by blood stasis or inappropriate activation of the coagulation cascade, often as a result of a defect in the normal defense hemostatic mechanisms. 

In premature infants, whose reserves of the vitamin are inadequate, vitamin E deficiency causes a shortened half-life of erythrocytes, which can progress to increased intravascular hemolysis, and hence hemolytic anemia. In infants treated with hyperbaric oxygen, there is a risk of damage to the retina (retro-lental fibroplasia), and vitamin E supplements may be protective, although this is not firmly established (Phelps, 1987). 

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