Extracorporeal oxygenators

All of the above-mentioned blood oxygenators are used outside the body, and hence are referred to as extracorporeal oxygenators. They are mainly used for heart surgery, which can last for up to several hours. However, blood oxygenators are occasionally used extracorporeally to assist the pulmonary function of the patients in acute respiratory failure (ARF) for extended periods of up to a few weeks. This use of extracorporeal oxygenators is known as extracorporeal membrane oxygenation (ECMO). 

The use of techniques of circulatory support (extracorporeal oxygenation and intra-aortic balloon pump) in seven cases of overdose with antidysrhythmic drugs (disopyramide, flecainide, prajmaline, and quinidine) has been reviewed (62). 

Lung. No implantable, artificial lung exists, and transplantation of this organ is relatively rare. Much work has been done, however, on extracorporeal oxygenators, which are used in over 100,000 operations each year. These oxygenators add fresh oxygen to the blood and permit removal of carbon dioxide. Several designs have... 

Frankenfeld. Li, and Asher" 49 4 have described an apparatus quite similar to dial shown in Fig. 19.4-6B for the extracorporeal oxygenation of blood. Bubbles of gaseous Oj. encapsulated in a fluorocarbon membrane, rise ihrongh oxygen-depleted blood. As they do so oxygen diffuses from the membrane into the blood while CD2 differes in the opposite direction and is swept ont. This process was reviewed earlier. 1" The key to its potential success is the use of fluorocarbons in the membrane phase.11,45 4 Fluorocarbons are uniquely compatible with human blood and circumvent the damage to blood cells which is encountered with conventional devices. 

Cattaneo, G., Straus, A., and Reul, H. 2004. Compact intra-and extracorporeal oxygenator developments. 

Other specialized appHcations of cardiac arrest devices include extracorporeal membrane oxygenation (ECMO) which occurs when the lungs of a premature infant caimot function properly. The market segments for cardiopulmonary support devices are potentially significant. 

Extracorporeal circulation Extracorporeal membrane oxygenation Fat embolism Heat stroke... 

In the oxygen-independent Type III reactions the excited/sensi-tized psoralen donates its excitation energy directly to, or reacts with, the target compound. This occurs if the substrate and the target compound (e.g., DNA) are already in close proximity or intercalated. The reactions will proceed very rapidly via the excited singlet state, and are, typically, cyclization reactions or electron-transfer between the sensitizer and the target. In addition, the psoralen can be ionized, either directly or via the excited state, and react with the target compound in the form of a radical cation. Furocoumarins are also employed in treatment of cutaneous T-cell lymphoma and some infections connected with AIDS, by so-called photopheresis processes [71, 74-76]. In this case, peripheral blood is exposed to, e.g., photoactivated (sensitized) 8-methoxypsoralen (8-MOP) in an extracorporeal flow system. This... 

Hart L, Cobaugh D, Sean B, et al. 1991. Successful use of extracorporeal membrane oxygenation ecmo in the treatment of refractory respiratory failure secondary to hydrocarbon. Vet Hum Toxicol 33(4) 361. 

Children-The recommended dose in pediatric patients is for a total daily dose of 2 to 4 mg/kg, to be divided and administered every 6 to 8 hours up to a maximum of 50 mg given every 6 to 8 hours. Limited data in neonatal patients (under 1 month of age) receiving extracorporeal-membrane oxygenation (ECMO) have shown that a dose of 2 mg/kg is usually sufficient to increase gastric pH to greater than 4 for at least 15 hours. Therefore, consider doses of 2 mg/kg given every 12 to 24 hours or as a continuous infusion. 

Serum samples and autopsy specimens were examined from two infants with congenital diaphragmatic hernia who had received life support with extracorporeal membrane oxygenation (ECMO). The serum levels of di(2-ethylhexyl) phthalate after 14 and 24 days of ECMO support were 26.8 and 33.5 mg/L respectively, and levels of 3.5, 1.0 and 0.4 mg/kg di(2-ethylhexyl) phthalate were found in liver, heart and testicular tissues, respectively, and trace quantities were found in the brain. The rate of di(2-ethylhexyl) phthalate extraction from the model PVC circuits was linear with time (rate, 3.5 and 4.1 mg/L per hour). The exposure to di(2-ethylhexyl) phthalate for a 4-kg infant on ECMO support for 3-10 days was estimated to be 42-140 mg/kg (Shneider et al., 1989). 

The toxicity of di(2-ethylhexyl) phthalate was evaluated in 28 term infants with respiratory failure, 18 of whom received extracorporeal membrane oxygenation (ECMO) and were compared with 10 untreated infants. Various clinical parameters of liver, pulmonary and cardiac dysfunction were found to be unaffected in treated infants, even though the rate of administration ranged up to 2 mg/kg bw di(2-ethylhexyl) phthalate over 3-10 days (mean peak plasma concentration, 8 pg/mL). ECMO is considered to be the clinical intervention that results in the highest intravenous dose of di(2-ethylhexyl) phthalate (Karle et al., 1997). 

Shneider, B., Schena, J., Traog, R., Jacobson, M. Kevy, S. (1989) Exposure to di(2-ethylhexyl)phthalate in infants receiving extracorporeal membrane oxygenation (Letter to the Editor). New Engl. J. Med., 320, 1563... 

A 13-year-old boy underwent a 17-hour craniotomy in an attempt to resect an arteriovenous malformation with propofol-based anesthesia. He developed frank propofol infusion syndrome after 74 hours of postoperative propofol sedation in the neurosurgical ICU (used to manage intracranial hypertension). Echocardiography showed severe biventricular dysfunction despite extraordinary pharmacological support. Extracorporeal circulation with membrane oxygenation (ECMO) was instituted at the bedside via cannulation of the left femoral vessels. Hemofiltration... 

Exposures of neonatal children to DEHP can be especially high as a result of some medical procedures. For example, upper-bound doses of DEHP have been estimated to be as high as 2.5 mg/kg/day during total parenteral nutrition (TPN) administration and 14 mg/kg/day during extracorporeal membrane oxygenation (ECMO) procedures. 

KarleVA, Short BL, Martin GR, etal. 1997. Extracorporeal membrane oxygenation exposes infants to the plasticizer, di(2-cthylhexyl)phthalatc. Crit Care Med25 696-703. 

Shneider B, Cronin J, Van Marter L, et al. 1991. A prospective analysis of cholestasis in infants supported with extracorporeal membrane oxygenation. JPediatr Gastroenterol Nutr 13 285-289. 

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