Pathophysiology of Post-Operative Hypovolemia

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Pathophysiology of post-operative hypovolemia
Hypovolemia occurs when there is a rapid depletion of the body fluid, which can lead to
multiple organ failure. This occurs due to the insufficient circulating volume of the bl0odd or the
body fluid, leading to subsequent inadequate perfusion of the fluids. It is a clinical condition,
where there is a decrease in the blood volume relative to vascular compartment that.
Hypovolemic shock is common in an individual due to acute internal loss of blood loss in the
thoracic cavity an in the abdomen. Anesthetic effect can also lead to hypovolemia. It is evident
from the case scenario, that the Eleanor has undergone a tumor surgery under prolonged
anesthesia. According to Noel-Morgan and Muir, (2018) it has been found that anesthesia causes
vasodilation that is related to an increase in the venous compliance, a reduced venous return and
a lessened response to the vasoactive substances. Hypovolemia might remain latent in a patient
depending upon the severity of the patient condition and due to impaired delivery of oxygen and
perfusion of the tissue (Taghavi & Askari, 2018). Isovolemic anemia cam occur, in case the
blood transfusion in not available and that is featured by a decreased content of the hemoglobin.
As per the values of the case assessment it can be seen that the hematocrit count of the patient
and the concentration of hemoglobin is less than the standard value, which can be related to
hemorrhagic shock. One of the risk factors related to hypovolemia is that it lowers the cardiac
output and also causes hypotension. This occurs by the decreasing the preload. Low blood

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pressure is also visible in Eleanor’s assessment report (BP- 90/54), which is much lower than the
standard value.
Trauma is common in patient who had undergone any crucial surgery like traumatic
fracture or resection of a tumor. It can be due to hypovolemia, occurring due to the profuse
blood loss.
The heart rate of Eleanor might is also high, which could have been due to the
hypovolemic shock. Eleanor’s data has displayed low urinary sodium as the kidney tries to
conserve the water and the sodium for expanding the extracellular volume.
Mechanism by which the body responds to hypovolemic shock
The body compensates with the hypovolemia and an increased sympathetic tone by an
increased heart rate, peripheral vasoconstriction and an enhanced vasoconstriction. Initially the
changes that can occur physiologically is an increase in the diastolic pressure, with a narrowed
down pulse pressure (Gulati, 2016). As a result of this the systolic blood pressure and the volume
status continues to decrease.
Some other complementary mechanism has also been found to be involved in the body
are the reflexes of the baroreceptors, chemoreceptors, the vasoconstrictors present in the
circulation, the renal absorption of the eater and sodium, reabsorption of the tissue fluids and
activation of the thirst mechanism (Gulati, 2016).

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A prompt reduction in the arterial blood pressure is sensed by the body with the help of
the arterial and the cardiopulmonary baroreceptors. As a result, the sympathetic adrenergic
system is activated augmenting the contractility and heart rate. Hence, there occurs an increase in
the systemic vascular resistance and the arterial pressure. Redistribution of the cardiac output
occurs from the less important organ to the more important organ (Gulati, 2016). Vasocontriction
is caused due to a reduction of the blood flow and a reduced arterial pressure. This reduced
arterial pressure might cause systemic acidosis, detected by the chemoreceptors.
It is the combined impact of the sympathetic activation and the arterial hypotension that
activates the humoral compensatory mechanism. It causes the sympathetic stimulation of the
adrenal glands that causes the secretion of the catecholamines in to the blood reinforcing the
impact of the sympathetic activation of the heart and the vasculature.
Hypotension in combination with the contraction of the precapillary resistance vessels
leads to a drop in the capillary hydrostatic pressure (Lonjaret, Lairez, Minville & Geeraerts,
2014). As a result of the reduced capillary pressure, filtration of the fluid from the blood occurs
in the interstitial space and the endothelium (Vincent & De Backer, 2013). Due to the reduction
in the hydrostatic pressure, less amount of the fluid leaves the capillaries. With a fall in the
pressure, there is a net fluid adsorption occurring from the tissue iterstitium back in to the
capillary plasma (Vincent & De Backer, 2013). It is evident from the case scenario that the
Hematocrit value of the patient was 0.36 that is higher than the normal value. This can be due to