Cardiac – Heart disease/hypertension/Myocardial Infarction/fluid control/renal/sickle cell. Flashcards
What is the main concept of fluid balance?
Fluid balance involves maintaining the proper amount of water and electrolytes in the body, which is crucial for normal cell and organ function. It includes the intake, distribution, and output of body fluids.
What are the primary compartments of fluid in the human body?
Intracellular fluid (ICF): 28L within the cells.
Extracellular fluid (ECF): 11L surrounding the cells, of which 3L is plasma and 8L is interstitial fluid.
What is osmolarity?
Osmolarity is the concentration of solutes in a solution, measured as milliosmoles per liter (mOsm/L), which is important for maintaining fluid balance in the body.
What is the difference between isotonic, hypotonic, and hypertonic fluids?
Isotonic: Equal solute concentration inside and outside the cell.
Hypotonic: Lower solute concentration outside the cell, causing water to move into the cell.
Hypertonic: Higher solute concentration outside the cell, causing water to move out of the cell.
What hormones regulate fluid balance?
ADH (Antidiuretic Hormone): Regulates water retention by the kidneys.
Aldosterone: Regulates sodium and water reabsorption in the kidneys.
Atrial Natriuretic Peptide (ANP): Regulates sodium and fluid balance, decreasing blood volume.
How does ADH (Antidiuretic Hormone) work?
ADH is released when blood osmolarity increases or blood volume/pressure decreases. It increases water reabsorption by the kidneys to conserve water and reduce osmolarity.
What triggers thirst in the body?
Thirst is primarily stimulated by:
Hypertonicity: Dehydration causing cellular dehydration.
Hypovolaemia: Low blood volume.
Hypotension: Low blood pressure.
Angiotensin II: Produced in response to low blood pressure or low blood volume.
What is water intoxication?
Water intoxication occurs when excessive fluid intake dilutes extracellular body fluids, causing swelling of cells, which can lead to coma and death. It can be caused by conditions like renal disease or excessive ADH production.
What is the role of aldosterone in fluid balance?
Aldosterone acts on the kidneys to promote sodium and water reabsorption, which increases blood volume and blood pressure. It also helps maintain electrolyte balance, particularly sodium and potassium levels.
What is the Renin-Angiotensin-Aldosterone System (RAAS)?
RAAS regulates blood pressure and fluid balance. When blood volume is low, renin is released from the kidneys, leading to the production of angiotensin II, which stimulates aldosterone release to conserve sodium and water.
What is Diabetes Insipidus?
Diabetes insipidus is a condition characterized by the lack of ADH or resistance to ADH, leading to the production of large volumes of dilute urine and excessive thirst.
What is the Syndrome of Inappropriate ADH Secretion (SIADH)?
SIADH is a condition where excessive ADH production leads to fluid retention, resulting in low sodium levels in the blood (hyponatremia) and potential fluid overload.
What is oedema and its causes?
Oedema is the accumulation of excess fluid in the interstitial spaces. It can result from increased blood pressure, venous blockage, increased capillary permeability, or decreased protein (e.g., in liver disease or malnutrition).
What is the role of capillary transport in fluid dynamics?
Capillaries exchange fluids, ions, and gases between the blood and tissues. Factors like blood pressure, osmotic pressure, and capillary permeability influence the movement of water and solutes across capillary walls.
What is shock?
Shock is an acute circulatory crisis characterized by hypotension and inadequate blood flow, which leads to oxygen and nutrient starvation of tissues, resulting in severe, potentially fatal symptoms.
What is Mean Arterial Pressure (MAP) and why is it important?
MAP = Diastolic BP + 1/3(Systolic BP – Diastolic BP).
A normal MAP is between 70 and 100 mmHg. If MAP drops below 60 mmHg, vital organs may not receive adequate blood supply, while higher MAPs may cause blood clots or heart muscle damage.
What are the main compartments for fluid in the body?
Intracellular Fluid (ICF): Fluid within cells.
Extracellular Fluid (ECF): Includes interstitial fluid and intravascular fluid (plasma).
Third Space: Fluid in non-functional areas like the peritoneal and pleural cavities.
What are the signs and symptoms of shock?
- Low blood pressure (reduced MAP).
- Increased pulse and respiration rate.
- Skin colour changes, anaerobic metabolism, and accumulation of metabolic waste.
- Decreased urine output and altered consciousness.
What are the stages of shock?
Initial Stage: No signs but cellular changes occur.
Compensatory Stage: Physiological adaptations to overcome the issue.
Progressive Stage: Compensatory mechanisms fail, leading to adverse effects.
Refractory Stage: Pathophysiological processes established, leading to death.
What is hypovolemic shock and its causes?
Hypovolemic shock is caused by a significant loss of blood or fluids. It can be due to blood loss (hemorrhage, trauma) or non-blood loss (vomiting, diarrhea, burns, polyuria).
What happens during the stages of hypovolemic shock?
Stage 1: Loss of 15% blood volume, mild symptoms like pale skin and anxiety.
Stage 2: Loss of 30% blood, increased heart rate, sweating, and delayed capillary refill.
Stage 3: Loss of 30-40%, low blood pressure, rapid heart rate, cold skin.
Stage 4: Loss of more than 40%, critical, with very low blood pressure and minimal urine output.
What is the treatment for hypovolemic shock?
Fluid replacement to restore blood volume, blood transfusion if needed, and vasopressors as a last resort to constrict blood vessels and increase blood pressure.
What is cardiogenic shock and its causes?
Cardiogenic shock occurs when the heart is unable to pump effectively due to conditions like heart failure, myocardial infarction, myocarditis, or valve stenosis.
How is cardiogenic shock treated?
Treatment includes improving myocardial function through arrhythmia management, reperfusion therapy (e.g., PCI), and the use of inotropes (e.g., dobutamine) and vasopressors.
What is obstructive shock?
Obstructive shock occurs when there is a blockage in the blood flow, such as in cardiac tamponade, pulmonary embolism, or tension pneumothorax.
How is obstructive shock treated?
Treatment is primarily directed at addressing the underlying obstruction. Once the obstruction is resolved, the patient’s condition often improves.
What is distributive shock and its causes?
Distributive shock occurs when there is an alteration in systemic vascular resistance (SVR), caused by conditions like sepsis, anaphylaxis, or spinal cord injury.
What is sepsis and how is it treated?
Sepsis is an infection leading to widespread inflammation, blood vessel dilation, and reduced SVR. Treatment involves screening for infection, using antibiotics, fluid replacement, and vasopressors (meds that increase bp by narrowing blood vessels) if necessary.