Replacement fluids toxicity

Factors that put patients at risk of lithium intoxication are those that increase intake (deliberately or accidentally), reduce excretion (kidney disease, dehydration, low sodium intake, drug interactions), or reduce body water (dehydration secondary to fluid restriction, vomiting, diarrhea, or polyuria) (66). Patients with lithium-induced polyuria are at a particular risk of toxicity if their ability to replace fluids is compromised (for example by anesthesia, over-sedation, CNS trauma). 

There does not appear to be an antidote of choice for bismuth toxicity in humans. Gastric lavage can be used within 1 h of exposure. Replace fluids and electrolytes. Monitor renal and liver function for several days and treat failure conventionally. The newer chelating agents, meso-2,3-dimercaptosuccinic acid and D,L-2,3-dimercapto-propane-l-sufonic acid, are being investigated experimentally as antidotes for bismuth toxicity, and the latter has been shown to be effective. In mice, D-penicillamine has proven effective. 

Several environmentally acceptable hydrofluorocarbons (HFCs) and hydrochlorofluo-rocarbons (HCFCs) have been identifled as possible substimtes for the regulated CFCs. However, HCFCs can be regarded only as transitional replacements. Their phaseout is scheduled for the year 2030. Possible replacement fluids are compiled in Table 17.3, together with their environmental properties, toxicity and flammability. Substances belonging to categories A and B are of main interest for the database project because, besides the above mentioned properties, their thermodynamic properties also are promising. 

While it would be difficult to enumerate all of the efforts in the area of implants where plastics are involved, some of the significant ones are (1) the implanted pacemaker, (2) the surgical prosthesis devices to replace lost limbs, (3) the use of plastic tubing to support damaged blood vessels, and (4) the work with the portable artificial kidney. The kidney application illustrates an area where more than the mechanical characteristics of the plastics are used. The kidney machine consists of large areas of a semi-permeable membrane, a cellulosic material in some machines, where the kidney toxins are removed from the body fluids by dialysis based on the semi-permeable characteristics of the plastic membrane. A number of other plastics are continually under study for use in this area, but the basic unit is a device to circulate the body fluid through the dialysis device to separate toxic substances from the blood. The mechanical aspects of the problem are minor but do involve supports for the large amount of membrane required. 

The simplest of the aldehydes is formaldehyde, whose molecular formula is HCHO. The second hydrocarbon backbone of the ketone is replaced by a hydrogen atom. Formaldehyde is a gas that is extremely soluble in water it is often sold commercially as a 50 percent solution of the gas in water. The gas itself is flammable, has an ignition temperature of 806°F and a strong, pungent odor, and is toxic by inhalation. Inhalation at low concentrations over long periods of time has produced illness in many people. Beside its use as an embalming fluid, formaldehyde is used in the production of many plastics and in the production of numerous other chemicals. 

Loop diuretics are useful in treating toxic ingestions of bromide, fluoride, and iodide, which are reabsorbed in the TAL. Saline solution must be administered to replace urinary losses of Na+ and to provide , so as to avoid extracellular fluid volume depletion. 

In recent years, many efforts are being made to avoid the problematic effects of solvents and many international and national regulations have been established (see Chapter 19 of Ref. [24]) toxic solvents are being replaced by non-toxic ones and environmentally hazardous solvents by harmless ones. The search for new environmentally benign reaction media is the subject of current research and there are many studies into the use of supercritical fluids and room temperature ionic liquids as such media (see 11 and Section 12.7). 

An interesting finding regarding potentially toxic chromium (and cobalt) in the body is elevated blood and urine levels of these metals in patients who have undergone total hip replacement.5 The conclusion of the study was that devices such as prosthetic hips that involve metal-to-metal contact may result in potentially toxic levels of metals in biological fluids. 

PCNs are a group of compounds with similar physical chemical properties to PCBs [65]. They contain one to eight chlorine atoms per naphthalene molecule and form a complex mixture of 75 congeners. They were produced before PCBs but were replaced by the latter compounds after incidents of worker-related toxicity [66]. Although the use of PCNs has declined in the past few decades, they are not prohibited in most countries and stiU occur in many PCB-like applications such as capacitor fluids, engine oil additives and electrical insulators [67]. 

Therapy consists of withdrawal of the antibiotic when diarrhea occurs and replacement of fluid and electrolyte losses. In less severe cases of antibiotic-associated diarrhea, no further treatment is needed. However, in patients with pseudomembranous colitis, a more intensive approach is usually required. When a toxic syndrome develops, fluid losses within the bowel can be very large. In these cases, a central venous line offers the chance to measure central venous pressure. Usually there is also loss of serum proteins and in some cases blood, which need appropriate replacement. In the rare cases with fulminant colitis and toxic megacolon, surgical intervention may be necessary (165,166). 

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