Final- Perioperative Fluid Therapy (7/25/23) Flashcards
What percentage of total body weight is water?
- 60%
Elderly and Obese patients will have lower percent of water in the body.
Pediatrics will have HIGHER percent of water in the body (Table 47.1)
What are the two main compartments fluid compartments?
- Intracellular Fluid (ICF) makes up two-thirds of total body water
- Extracellular Fluid (ECF) makes up one-third of total body water
What are the different compartments of the ECF?
- Interstitial: lymphatics and protein-poor fluid around the cell.
- Intravascular: plasma volume
- Transcellular: GI Tract, Urin, CSF, Joint fluid, aqueous humor.
What is diffusion?
Speed is ______ to the _________^2?
It can also be related to ________ _________.
- Can occur across permeable membranes
- Solute particles moving or filling solvent volume
- High to Low concentration
- Speed is proportional to the distance squared
- Can relate to electrical gradients
What are examples of the type of solutes that are in our body?
- Glucose
- Protein (Albumin)
- Electrolytes
What is the primary extracellular cation?
- Sodium (Na+)
What is the primary intracellular cation?
- Potassium (K+)
What is osmosis?
- Semipermeable membrane that separates pure water from water with solute.
- Osmosis is just the movement of WATER
- Diffuses from low to high solute concentration
What is osmotic pressure?
- Pressure that resists the movement of water through osmosis
What is osmotic pressure affected by?
- Temperature
- Number of Molecules
- Volume
PV = nRT
What is osmolarity?
- Number of osmotically active particles per L of solvent
- Higher osmolarity, higher “pulling power”
Patient A has serum glucose of 600mg/dl
Patient B has serum glucose of 250mg/dl
Who has higher osmolarity?
- Patient A
What is osmolality?
- Number of osmotically active particles per Kg of solvent
What is normal osmolality?
- 280-290 mOsm
What is oncotic pressure?
- The component of total osmotic pressure due to colloids
List examples of colloids
- Albumin
- Globulins
- Fibrinogen
What percentage of oncotic pressure is due to albumin?
- 65-75%
What makes up our daily intake?
- Solids (750 mL)
- Liquids (1400 mL)
- Metabolism (350 mL)
What makes up our daily output?
- Insensible Loss (1000 mL)
- GI loss (100 mL)
- Urine output (0.5-1 mL/kg/hr)
Urine secretion accounts for ____-% of daily water loss.
- 60%
What hormones regulate urine output?
- ADH
- ANP
- Aldosterone
How does ADH regulate urine output?
Increases water reabsorption in the collecting ducts; concentrates urine/↓ urine volume
How does ANP regulate urine output?
- ANP is activated by ↑ fluid volume
- ↑ Atrial Stretch = ↑ Renal Excretion
How does Aldosterone regulate urine output?
- Regulates sodium and potassium levels
- Aldosterone is released if sodium and fluid volume decreases, causing sodium and water conservation.
What are the sensors for fluid balance?
- Hypothalamic osmoreceptors
- Low-pressure baroreceptors (large veins and RA)
- High-pressure baroreceptors (carotid sinus and aortic arch)
What is the trigger for fluid balance?
- Increased thirst or increase ADH
What are the compensatory mechanisms for acute disturbances in circulating volume?
- Venoconstriction
- Mobilization of venous reservoir
- Autotransfusion from ISF to plasma
- Reduced urine production
- Maintenance of CO…tachycardia, increased inotropy
Where is Renin released?
What does Renin do to angiotensinogen?
- Released from juxtaglomerular cells
- Cleaves angiotensinogen to make angiotensin I
When ANG I → ANG II, what will this cause?
- Vasoconstriction and aldosterone release
Where is aldosterone released from?
- Aldosterone is released from the adrenal cortex and causes salt and water retention
In the absence of ongoing fluid loss, loss volume should be restored within ______- hours (range).
- 12-72 hours
In the absence of ongoing fluid loss, RBC should be restored through erythropoiesis in ______ weeks (range).
- 4-8 weeks.
What are the Electrolytes and Osmolarity of Normal Saline (0.9%)?
Na+: 154 mEq/L
Chloride: 154 mEq/L
Osmolarity: 308 mOsm/L
What are the Electrolytes and Osmolarity of LR?
Na+: 130 mEq/L
K+: 4 mEq/L
Chloride: 109 mEq/L
Lactate: 28 mEq/L
Osmolarity: 274 mOsm/L
What are the Electrolytes and Osmolarity of Plasmalyte?
Na+: 140 mEq/L
K+: 5 mEq/L
Cl-: 98 mEq/L
Acetate: 27 mEq/L
Osmolarity: 295 mOsm/L
What are the Electrolytes and Osmolarity of Albumin 5%?
Na+: 145 +/- 15 mEq/L
K+: <2.5 mEq/L
Cl-: 100 mEq/L
Osmolarity: 330 mOsm/L
What are the Electrolytes and Osmolarity of Hetastarch 6%?
Na+: 154 mEq/L
Cl-: 154 mEq/L
Osmolarity: 310 mOsm/L
What are crystalloids?
- Solutions of electrolytes in water
- The are called balanced solutions (not really though, misnomer)
- LR is probably considered the most “balanced” crystalloid