Fluid requirement maintenance

Calculate the daily maintenance fluid requirement for patients given their age, weight, and gender. 

Once TBW has been restored, the volume of maintenance fluid equals the basal fluid requirement plus ongoing exceptional losses. If the pathophysiologic process leading to TBW depletion has not been identified and corrected (or accounted for in the calculation of maintenance fluid requirements), TBW depletion will quickly recur. To review the concepts involved in the calculation of replacement fluids for a representative patient (see Patient Encounter 2). 

TABLE 24-2. Useful Calculations for the Estimate of Patient Maintenance Fluid Requirements... 

PN generally should not be used to treat acute fluid abnormalities. Rather, PN should be adjusted to minimize worsening of underlying fluid disturbances, taking into account other fluids the patient is receiving. Daily maintenance fluid requirements for adults can be estimated with the following equation ... 

Base fluid administration on calculated maintenance or replacement fluid requirements. 

The goal of the maintenance phase of fluid therapy is to supply the basal fluid requirement of the horse ("maintenance" rate) and replace ongoing fluid losses. The mean daily water intake (including the water content of feed) of normal... 

Rehydration and maintenance of water and electrolytes are primary treatment goals until the diarrheal episode ends. If the patient is volume depleted, rehydration should be directed at replacing water and electrolytes to normal body composition. Then water and electrolyte composition are maintained by replacing losses. Many patients will not develop volume depletion and therefore will only require maintenance fluid and electrolyte therapy. Parenteral and enteral routes may be used for supplying water and electrolytes. If vomiting and dehydration are not severe, enteral feeding is the less costly and preferred method. In the United States, many commercial oral rehydration preparations are available (Table 36-3). 

Regardless of the serotypes, the primary goal of therapy is restoration of fluid and electrolyte losses caused by watery diarrhea. ORT is the preferred method of rehydration, and several studies showed reduction in fluid requirements by 32% to 35% when rice-based instead of glucose-based ORT solutions are used (50-80 g rice instead of 20 g glucose per liter). In patients who cannot tolerate ORT, IV Ringer s lactate solution can be used. Normal saline is not recommended because it does not correct metabolic acidosis. After rehydration, maintenance fluid is given based on accurate recording of intake and output volumes. 

The conventional mode of surface transportation of fluids before the advent of CCP was by sea, rail, or road transport. These modes are still in use for petrol, diesel, LPG, and several hydrocarbons however, wherever bulk transportation on a continuous basis is required between two fixed locations, use of CCP is the most economical solution. The modes of transport other than CCP have the following limitations nonavailability of sufficient roads, rail tracks, and port-harbor facilities to take up the traffic load procedures and control involved in the transport operation (permits/licenses/OctroiAoll/ regional transport office, etc.) and logistics such as manpower requirement, maintenance, fuel cost, availability, weather and climate, pollution generated, safety, insurance, and security. 

Economic Considerations. The principal economic consideration is, of course, total installed system cost, including the initial cost of the flow primary, flow secondary, and related ancillary equipment as well as material and labor required for installation. Other typical considerations are operating costs and the requirements for scheduled maintenance. An economic factor of increasing importance is the cost of disposal at the end of normal flow meter service life. This may involve meter decontamination if hazardous fluids have been measured. 

Active Transport. Maintenance of the appropriate concentrations of K" and Na" in the intra- and extracellular fluids involves active transport, ie, a process requiring energy (53). Sodium ion in the extracellular fluid (0.136—0.145 AfNa" ) diffuses passively and continuously into the intracellular fluid (<0.01 M Na" ) and must be removed. This sodium ion is pumped from the intracellular to the extracellular fluid, while K" is pumped from the extracellular (ca 0.004 M K" ) to the intracellular fluid (ca 0.14 M K" ) (53—55). The energy for these processes is provided by hydrolysis of adenosine triphosphate (ATP) and requires the enzyme Na" -K" ATPase, a membrane-bound enzyme which is widely distributed in the body. In some cells, eg, brain and kidney, 60—70 wt % of the ATP is used to maintain the required Na" -K" distribution. 

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