Pharma Fouda 1_p112-114 PDF

– Diuretics are better avoided during pregnancy because they effectively reduce maternal plasma volume and consequently may reduce amniotic fluid and/or placental blood flow. Part 4: Volume depletion and fluid replacement  Volume depletion can be...

– Diuretics are better avoided during pregnancy because they effectively reduce maternal plasma volume and consequently may reduce amniotic fluid and/or placental blood flow. Part 4: Volume depletion and fluid replacement  Volume depletion can be caused by loss of blood or other body fluids e.g. vomiting, diarrhea, etc.  In cases of mild volume depletion, resuscitation can be adequately achieved with oral fluid alone. Sodium chloride tablets and electrolyte-containing solutions are often used.  In cases of severe dehydration, i.v. fluid therapy is preferred and may be life-saving.  Water alone is not an appropriate fluid for volume resuscitation since it enters the cells by osmotic effect. Only one third of each administered liter remains in the extracellular space, and only one twelfth of each administered liter remains in the intravascular space.  When electrolyte disturbances are present, the fluid used for resuscitation should be chosen to correct both volume depletion and electrolyte disturbances. █ Crystalloid solutions Sodium chloride solutions:  Normal saline (0.9% NaCl): It is the most commonly used solution. It contains 154 mEq sodium per litre, a concentration similar to the sodium concentration of plasma. Due to the relatively high chloride content, normal saline carries a risk of inducing hyperchloraemic metabolic acidosis when given in large amounts.  Hypotonic saline (0.45% NaCl): contains 77 mEq sodium per liter, and can be used when there is dehydration with hypernatraemia. In these patients, 5% dextrose in water can be given simultaneously with normal saline.  Hypertonic saline (3% NaCl): contains 513 mEq sodium per liter, and can be used for management of acute hyponatremia. Lactated Ringer’s solution:  It is an isotonic solution containing sodium, potassium, chloride, calcium and lactate. The lactate is metabolized by the liver into bicarbonate, which can help correct metabolic acidosis. In lactic acidosis and liver disease this conversion is impaired, so lactate-containing fluids should be avoided.  It is not suitable for maintenance therapy because the Na+ and K+ contents are too low to compensate for daily electrolyte requirement. 98  Glu ucose (Dex xtrose) solutions:  Variious conceentrations are availab ble e.g. 5% %, 10% and 25%. Thhe 5% dex xtrose in watter (also kn nown as D55W) is isottonic and is s the mostt commonlly used.  Hyp pertonic glucose solutions (ab bove 5%) should be b infused very slow wly and cau utiously to avoid a hype erosmolarr syndrom me and life--threateninng dehydra ation. █ Collo oid solutions  Colloids are classified c as either n natural (albumin and fresh frrozen plassma) or artifficial (starc ch and dexxtran).  Theey preserve a high colloid c osm motic pre essure in the t blood and theoretically dessigned to increase i thhe intravasscular volu ume with much lesss effect on n tissue watter. Howe ever, collo oid solut ions are a less-p preferred choice for f the man nagement of volume e depletionn because they are very expenssive and have not shoown a morttality beneffit over iso otonic salin ne. █ Orall rehydrattion thera apy (ORT T)  Oraal electrolyyte solution ns are useed in childdren, particularly witth gastroe enteritis. Thiss product contains sodium, s po otassium, chloride, c citrate, c and d dextrose e, and is dessigned to replace th he electrolyytes and water thatt are lost with vom miting or diarrrhea.  Glucose is typ pically add ded to thesse oral repllacement solutions s too promotee uptake of ssodium via the intestiinal sodium m/glucose co-transporter mechhanism. Part 5: Dis sorders of serum m sodiu um and potassiu p um █ Hypo onatremiia and SIA ADH  Hypponatremia a is defineed as seru um Na+ mEq//L, and rep presents a state of hyp perosmolality  Hyppernatremia may be caused byy a primary y Na+ gainn or a watter loss, th he latter ng much more com bein mmon. Re enal wate er loss results from m either osmotic o diurresis or diiabetes ins sipidus (D DI).  Hyppernatremia results in contracttion of brain cells as water sh hifts to attenuate a the risingg ECF osm molality. Th hus, the most m seveere sympto oms of hyp pernatremia a are neuro ological maanifestatio ons. Manag gement of symptom matic hype ernatremia a  The e mainstay of manage ement is th he adminis stration of water, prreferably by b mouth h or nasoogastric tube e. Alternattively, 5% dextrose e in water (D5W) can n be given intravenou usly.  Speecific thera apy of the underlying u cause. 100