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Manual compression of the reservoir bag is an example of which law?
Boyle's law; with temperature constant, the volume of gas is inversely proportional to pressure.  As the gas in the reservoir bag is compressed, the pressure increases and gas is transferred to the patient.
What are the determinants of vapor pressure?
The physical characteristics of the liquid and the temperature.  As temperature increases, VP increases.  VP is independent of atmospheric pressure.
What does halogenation of volatile anesthetics do?
Reduces flammability and increases potency
What reaction occurs when CO2 is absorbed by sodalime?
1.  Carbon dioxide combines with water to form carbonic acid
2.  Carbonic acid reacts with sodium hydroxide to form sodium carbonate and water
3.   Finally, calcium hydroxide reacts with sodium carbonate to produce calcium carbonate and regenerate sodium hydroxide
How do you calculate the volume of vapor produced by 1 mL of sevoflurane (specific gravity = 1.5 gm, molecular weight = 180 gm)?
Avogadro's law states that 1 mole = 22.4 L/mole at STP

1.5/180 = 0.0083 moles, 22.4 x 0.0083 = 186 L

Use Charle's Law to adjust to 20 C (293 K)

186/273 = V/293, V = 200 mL
If oxygen e-cylinders are brought from a hot environment to a cold environment what is the effect on the contents?  What law is this?
Volume and pressure both decrease; Combined Gas Law
What is the critical temperature of oxygen?
-118 C
What is sea level barometric pressure?
760 mm Hg
Define microshock
With direct application of current to the myocardium, from intracardiac monitors or pacing wires, currents of as low as 100 microamps have been shown to cause ventricular fibrillation.
When terminating an anesthetic, what are the factors that determine the transfer of anesthetic gases from the blood to the alveoli?
Fick's law of diffusion: Membrane surface area, temperature, differences in partial pressure between the blood and alveoli, and the thickness of the alveolar-capillary membrane.
Describe the synthesis of norepinephrine
In the liver:
1.  Phenylalinine is converted to tyrosine by phenylalinine hydroxylase
2.  Tyrosine is converted to dopa by tyrosine hydroxylase (RATE LIMITING STEP)
3.  Dopa is converted to dopamine by dopa decarboxylase (then transported to storage vessels within the nerve terminal)
4.  Dopamine is converted to norepinephrine by dopamine B-hydroxylase.

(Norepinephrine is converted to epinephrine in the adrenal medulla via PNMT)         
What is the anion gap a measurement of?
Plasma cations (Na) - Plasma anions (Cl + HCO3)

Increased with increased production of endogenous acids (lactic acidosis)
How can gases be liquified by pressure?
Only if stored below their critical temperature
The critical temperature of air is?  This means?
-140.6 C; it exists as a gas in cylinders
At what magnitude is electrical current perceptible to touch?
1 mA
What is the maximum leakage allowed in operating room equipment?
10 microamps
Describe the secondary wiring of an isolation transformer
Not grounded, provides two live ungrounded voltage lines for operating room equipment
What causes malfunction of the return electrode, what will result?
Disconnection from the ESU, inadequate patient contact, or insufficient conductive gel.  The current will find another place to exit (ECG pads, or metal parts of table), resulting in a burn.
What are the three contributors to operating room fires and explosions?
Flammable agents (fuels), Gases supporting combustion (oxidizers), Ignition sources (heat)
What is osmotic pressure mainly dependent on?
The number of nondiffusible solute particles; Average kinetic energy of particles in solution is similar regardless of mass
What is the most important determinant of intracellular osmotic pressure?
Potassium
What is the most important determinant of extracellular osmotic pressure?
Sodium
What is the fluid exchange between the intracellular and interstitial spaces governed by?
The osmotic forces created by differences in nondiffusible solutes in concentrations
Below what level of plasma sodium concentrations are serious manifestations of hyponatremia present?
120 mEq/L
What is very rapid correction of hyponatremia associated with?
Demyelinating lesions in the pons (central pontine myelinosis), resulting in serious neurological sequelae
What is the major hazard of increases in extracellular volume?
Impaired gas exchange due to pulmonary insterstitial edema, alveolar edema, or large collections of pleural or ascitic fluid
Which patients should receive IV replacement of KCl?
Those with or at risk for serious cardiac manifestations or muscle weakness
Which level of hyperkalemia should always be treated due to lethality?
> 6 mEq/L
What is the most effective treatment of symptomatic hypercalcemia?
Rehydration followed by brisk diuresis (urinary output 200-300 mL/h) with administration of IV saline and a loop diuretic (to accelerate Ca excretion)
Symptomatic hypocalcemia should be emergently treated with what?
IV calcium chloride (3-5 mL of a 10% solution) or calcium gluconate (10-20 mL of a 10% solution)
What may some patients with severe hypophosphatemia require?
Mechanical ventilation postoperatively
What can marked hypermagnesemia lead to?
Respiratory arrest
When should isolated hypomagnesemia be corrected?
Prior to elective surgery because of its potential for causing cardiac arrhythmias
What volume of fluid is in the extracellular space?  What percentage of total body water and body weight is this?
28L; 67% body water, 40% body weight
What compartments make up the extracellular space?
Interstitial and intravascular
What volume of fluid is in the interstitial space?  What percentage of total body water and body weight is this?
10.5L; 25% body water, 15% body weight
What volume of fluid is in the intravascular space?  What percentage of total body water and body weight is this?
3.5L; 8% body water, 5% body weight
How much fluid volume does the body hold?  What percentage of body weight is this?
42L; 60%
What are the components of intracellular fluid?
In mEq/L:
Sodium 10
Potassium 140
Calcium < 1
Magnesium 50
Chloride 4
Bicarbonate 10
Phosphorus 75
Protein 16            
What are the components of intravascular fluid?
In mEq/L:
Sodium 145 (142 interstitial)
Potassium 4
Calcium 3
Magnesium 2
Chloride 105 (110 interstitial)
Bicarbonate 24 (28 interstitial)
Phosphorus 2
Protein 7 (2 interstitial)
What is the net pressure at the arterial end of the capillary?  At the venous end?
13 mm Hg; 7 mm Hg
How is plasma osmolality calculated?
2 x Plasma sodium concentration
How is total body osmolality calculated?
(Extracellular solutes + Intracellular solutes)/TBW
What are the major causes of hypernatremia?
Impaired thirst: Coma, Essential hypernatremia
Solute diuresis:  Osmotic diuresis: diabetic ketoacidosis, noketotic hyperosmolar coma, mannitol administration
Excessive water losses: Renal (Neurological diabetes insipidus, nephrogenic diabetes insipidus), Extrarenal (Sweating)
Combined disorders: Coma plus hypertonic nasogastric feeding
What is the most common cause of hypernatremia with a normal total body sodium content?
Diabetes insipidus
How is hypernatremia resulting from water and sodium loss treated?
By replacing isotonic loss and water deficit
How is hypernatremia form pure water loss treated?
By replacing water deficit
How is hypernatremia from increased sodium content treated?
By giving a loop diuretic and replacing any water deficit
What are the causes of pseudohyponatremia?
Hyponatremia with normal plasma osmolality: Asymptomatic (marked hyperlipidemia, marked hyperproteinemia) and Symptomatic (marked glycine absorption during transurethral surgery)

Hyponatremia with an elevated plasma osmolality: Hyperglycemia, Administration of mannitol
How is hypoosmolal hyponatremia classified?
Decreased total sodium content: Renal (diuretics, mineralocorticoid deficiency, salt-losing nephropathies, osmotic diuresis [glucose, mannitol], renal tubular acidosis), Extrarenal (vomiting, diarrhea, integumentary loss [sweating, burns], "third-spacing"

Normal total sodium content: Primary polydipsia, syndrome of inappropriate antidiuretic hormone, glucocorticoid deficiency, hypothyroidism, drug-induced

Decreased total sodium content: Congestive heart failure, cirrhosis, nephrotic syndrome
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