At an optimum end-diastolic volume occurs at maximum stroke volume and cardiac output is achieved.
Beyond this optimum volume, there volume overload, and stroke volume is diminished.
Refers to the state of one of the chambers of the heart in which too large a volume of blood exists within it for it to function efficiently.
Ventricular volume overload is equivalent to an excessively high preload.
Ventricular volume overload is a cause of cardiac failure.
The myocardium contracts more powerfully as the end-diastolic volume increases, as stretching of the myofibrils in cardiac muscle causes them to contract more powerfully due to a greater number of cross-bridges being formed between the myofibrils within cardiac myocytes.
Beyond this point the ability to contract diminishes due to loss of connection between myofibrils.
The common finding in volume overload is high cardiac output with a low or normal afterload.
The output may be high due to the inefficiency in valve disease, or it may be high due to shunting of blood in left-to-right shunts and arteriovenous malformations.
Inverted u waves on the electrocardiogram, may be seen in left ventricular volume overload.
Volume overload common among critically ill patients with kidney, heart, and liver disease is mainly as a result of aggressive fluid resuscitation.
Causes of left ventricular volume overload:
Valvular heart disease
Aortic regurgitation
Mitral regurgitation, also causing left atrial volume overload
Congenital heart defects
Patent ductus arteriosus
Ventricular septal defect, also causing left atrial volume overload
Arteriovenous malformation and fistula
Giant hepatic haemangioma
High-output haemodialysis fistula
Right ventricular volume overload
Valvular heart disease
Tricuspid regurgitation
Pulmonary regurgitation
Congenital heart defects
Atrial septal defect, also causing right atrial volume overload
Removing fluid with diuresis or ultra filtration can i prove volume overload in critically ill patients.
Removing fluid can lead to hypotension,renal insufficiency , neurologic events, and ototoxicity.
Hypertonic albumin solution or elastic bandages can mobilize extravascular volume during the active fluid removal phase of critical illness.
Administering albumin with furosemide in patients with hypoalbuminemia is associated with increased urine volume and sodium excretion.
Patient with hypoalbuminemia have increased furosemide volume distribution and decreased furosemide transportation efficiency at the proximal tubule.
Therefore intravenous albumin may improve the fluid removal rate with loop diuretics.
The exertion of external compression counteracts capillary fluid infiltration by increasing local tissue pressure and enhances reabsorption by squeezing fluid from the interstitial space into the veins and lymphatic system.
Compression reduces the diameter of major veins in the lower extremities, Which causes a reduction of local blood volume and redistribution of blood towards central circulation increasing preload and cardiac output.