Dehydration hypovolemia

Dehydration, hypovolemia, and hyperkalemia (in primary adrenal insufficiency only)... 

Severe dehydration leading to hypotension and shock (circulatory collapse). Hypovolemia may not be responsive to intravenous hydration and may require the use of vasopressors. 

Glycerin Suppository [Laxative] Uses Constipation Action Hyperosmolar laxative Dose Adults. 1 adult supp PR PRN Feds. 1 infant supp PR daily-bid PRN Caution [C, ] Disp Supp SE D Interactions T Effects W/ diuretics EMS Monitor ECG and BP for signs of hypovolemia and electrolyte disturbances d/t D OD Unlikely but may cause severe D and dehydration symptomatic and supportive... 

Uses Suppress/eluninate bacteriuria associated w/ chronic/recurrent UTI Action Converted to formaldehyde ammonia in acidic urine nonspecific bactericidal action Dose Adults. Hippurate 0.5-1 g bid. Mandelate 1 g qid PO pc hs Peds 6-12 y. Hippurate 25-50 mg/kg/d PO bid. Mandelate 50-75 mg/kg/d PO qid (take w/ food, ascorbic acid w/ adequate hydration) Caution [C, +] Contra Renal insuff, severe hepatic Dz, severe dehydration sulfonamide allergy Disp Tabs SE Rash, GI upset, dysuria, t LFTs EMS Monitor BP for hypovolemia and dehydration OD Sxs unknown symptomatic and supportive... 

Because Henle s loop is indirectly responsible for water reabsorption by the downstream collecting duct, loop diuretics can cause severe dehydration. Hyponatremia is less common than with the thiazides (see below), but patients who increase water intake in response to hypovolemia-induced thirst can become severely hyponatremic with loop agents. Loop agents are sometimes used for their calciuric effect, but hypercalcemia can occur in volume-depleted patients who have another—previously occult—cause for... 

In the patient with contact lenses, it is advised not to use diclofenac preparations for ophthalamic treatment. Diclofenac also is contraindicated for intravenous administration in patients with renal impairment, hypovolemia, dehydration, asthma, or cerebrovascular bleeding. 

Conditions that result in the loss of large volumes of body fluids, such as high-volume diarrhea and gastric reflux, obviously require aggressive fluid therapy. However, many other horses may require fluid therapy because of prolonged mild-to-moderate fluid losses or prolonged reduced fluid intake. In neonatal foals, reduced fluid intake can rapidly result in hypovolemia and severe dehydration. This section addresses the identification of these horses and foals. 

The clinical signs of hypovolemia and dehydration in the adult horse are listed in Table 17.1. Hypovolemia is defined as insufficient circulating blood volume, whereas dehydration is defined as loss of water from the tissues. It is important to distinguish between these conditions because hypovolemia requires immediate treatment but dehydration is optimally addressed over a period of 12-24 h. However, in most clinical scenarios, hypovolemia and dehydration occur concurrently. 

Table 17.1 Clinical signs of hypovolemia and dehydration in the horse...

However, in the horse, the administration of a highly concentrated formula of hypertonic saline-dextran 70 resulted in clinically apparent intravascular hemolysis and hemoglobinuria (Moon et al 1991). Whether less-concentrated formulas are suitable for the horse remains to be investigated. The combination of an alternative colloid, hetastarch (lOml/kg), and hypertonic saline (4 ml/kg) may be an appropriate solution for the resuscitation of horses that are both hypovolemic and dehydrated. Clinical experience suggests that hypertonic-saline-hetastarch is particularly useful in horses with marked hypovolemia and hypoproteinemia, such as those with severe colitis, but this has not been formally evaluated in experimental studies or clinical cases. 

The administration of plain water is of minimal benefit to restore plasma volume in horses exercised in hot and humid conditions (Marlin et al 1998). However, the administration of an ORS or an electrolyte paste together with the provision of fresh drinking water may be sufficient to supplement water and electrolytes following vigorous or prolonged exercise in dehydrated horses with orily mild hypovolemia (Marlin et al 1998, Sosa Leon et al 1998). 

Hypernatremia in the setting of decreased ECF is caused by the renal or extrarenal loss of hypoosmotic fluid leading to dehydration. Thus once hypovolemia is established, measurement of urine Na" " and osmolality is used to determine the source of fluid loss. Patients who have large extrarenal losses have a concentrated urine (>800 mOsmol/L) with low urine Na (<20 mmol/L), reflecting the proper renal response to conserve Na and water as a means to restore ECF volume. Extrarenal causes include diarrhea, skin (burns or excessive sweating), or respiratory losses coupled with failure to replace the lost water. When gastrointestinal loss is excluded, and the patient has normal mental status and access to H2O, a hypothalamic disorder (tumor or granuloma) should be suspected, because the normal thirst response should always replace insensible water losses. 

Furosemide (Lasix) Inhibits chloride reabsorption in thick ascending loop of Henie. High loss of K+ in urine. Preferred diuretic in patients with low GFR and in hypertensive emergencies. Also, edema, pulmonary edema, and to mobilize large volumes of fluid. Sometimes used to reduce serum potassium levels. Hyponatremia, hypokalemia, dehydration, hypotension, hyperglycemia, hyperuricemia, hypocalcemia, ototoxicity, sulfonamide allergy, hypomagnesemia, hypochloremic alkalosis, hypovolemia. 

Hematocrit levels also can indirectly indicate fluid volume in the blood. Since the test measures the number of blood cells per volume of blood, increased fluid in the blood, that is, hypervolemia, will dilute the blood cells and cause the hematocrit level to decrease. The normal range of values for men is 39 to 49 percent and for women is 35 to 45 percent. Consequently, too little fluid in the blood, that is, hypovolemia, will cause hemoconcentration and result in a high hematocrit level. It is therefore important to consider the patient s hydration level when interpreting laboratory values. For example, a hematocrit that falls within range or above range in a patient who is dehydrated actually may be low when the patient is fully hydrated. 2 Use other laboratory values, such as specific gravity, to see a full picture. 

Hypovolemia is a deficiency of body fluid that results when there is a total decrease in the fluid volume in the body or a relative decrease in body fluid owing to fluid loss from the blood vessels into the tissues. Hypovolemia can be classified as fluid volume deficit—the loss of water and sodium from the body—or as dehydration— the loss of water from the body in excess of sodium, resulting in an increased osmolality. While hypovolemia has significance relative to circulatory needs, loss of fluid accompanied by changes in osmolality and sodium concentration in the body has a more profound impact on the body and survival. The detrimental result is that... 

In dehydration, fluid volume is also decreased, but there is an increase in the osmolality of the blood because an equivalent amount of sodium was not lost. This form of hypovolemia occurs when fluid is lost but not replaced because the individual is unable to drink (e.g., an infant, an unconscious child or adult, or someone stranded without access to drinkable water) or did not experience the normal thirst impulse (e.g., elderly persons). The result would be a loss of water without replacement and without an equal loss of sodium, resulting in an elevation in sodium concentration in the blood and increased serum osmolality. Dehydration can occur through such mechanisms as profuse sweating, diuresis (e.g., in diabetes insipidus [deficient ADH] or diabetes mellitus and osmotic fluid loss), or excessive diuretic use. 2... 

A common cause of true hypovolemia is dehydration owing to inadequate intake of fluids, excessive loss of fluids, or a combination of the two. Dehydration is a true danger in the elderly because the thirst mechanism, which stimulates one to drink fluids, is diminished with age. Additionally, children, whose total-body fluid content is high and have high fluid needs, can dehydrate more quickly than adults if they are ill and nausea or gastrointestinal upset causes them to refuse fluid intake. 2... 

Assess signs of dehydration and hypovolemia, including Poor skin turgor Dry mucous membranes Orthostatic hypotention Decreased urine volume (< 30 mL/h)... 

Normal physiologic response to fever, exercise, anxiety, pain, dehydration may also accompany shock, left-sided heart failure, cardiac tamponade, hyperthyroidism, anemia, hypovolemia, pulmonary embolism, and anterior-wall myocardial infarction (Ml). 

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