Blood hypovolemia

Ineffective Tissue Perfusion related to hypovolemia, blood loss, impaired distribution of fluid, impaired circulation, impaired transport of oxygen across alveolar and capillary bed, other (specify)... 

FIGURE 10-4. Treatment algorithm for the management of moderate to severe hypovolemia. BP, blood pressure CVP, central venous pressure ECG, electrocardiogram MAP, mean arterial pressure PA, pulmonary artery PAOP, pulmonary artery occlusion pressure PRBCs, packed red blood cells SBP, systolic blood pressure. 

When cardiac output is reduced by heart failure, the resultant changes in blood pressure and blood flow to the kidney are sensed as hypovolemia and lead to renal retention of salt and water. This physiologic response initially increases intravascular volume and... 

Many of the components of injury can influence aldosterone secretion, and sodium depletion and hypovolemia are probably the most important (B7, S5). Hemorrhage alone can also stimulate aldosterone secretion rate. A raised concentration of potassium in blood and excess 5-hydroxy-tryptamine from injured tissues have both been shown to increase aldosterone secretion (Mil). 

Hypovolemia is a powerful stimulus for adrenomedullary secretions, and the restoration of the blood volume will reduce significantly any previously induced secretion of catecholamines (W2). Experiments in animals have shown that the response to hypovolemia does not occur if the adrenal gland has been denervated (H2). The afferent arc of this reflex pathway has not been identified. 

Although furosemide has embryotoxic properties in some animal species, it has been widely used in pregnant women without any adverse effects. Nevertheless, it should be used with great caution, since hypovolemia can lead to reduced uterine and placental blood flow. Careful monitoring of fetal heart action is necessary. Furosemide passes the placenta and increases fetal urine production. It can also increase acid concentrations in maternal serum, fetal serum, and amniotic fluid, thus masking a useful index for the development of pre-eclampsia (24). Its use in pregnant women should therefore be restricted to the treatment of cardiac failure. 

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. 

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