Pharm Quiz 3 Flashcards
What is the blood gas partition of Isoflurane?
1.46
What is the blood gas partition of nitrous oxide?
0.46
What is the blood gas partition of desflurane?
0.42
What is the blood gas partition of sevoflurane?
0.69
What is the mac % of isoflurane?
1.17 %
What is the mac % of desflurane?
6.6 %
What is the mac % of sevoflurane?
1.8 %
What is the mac % of nitrous oxide?
104 %
What 5 things increases the % of MAC delivered?
- hyperthermia
- red hair
- drug increased CNS catecholamine levels
- cyclosporine
- hypernatremia
What 14 things decreases % of MAC delivered?
- hypothermia
- increasing age
- drug decreased CNS catecholamine levels
- benzos, opioids
- hyponatremia
- alpha-2 agonists
- alcohol intoxication
- pregnancy
- lithium
- lidocaine
- hypoxemia
- hypotension
- CPB
- Neuroaxial opioids
What are 11 things that do nothing to the % of MAC delivered?
- anesthetic metabolism
- alcoholism
- gender
- duration of anesthetic
- PaCO2 15-95 mmHg
- PaO2 >38 mmHg
- BP > 40 mmHg
- hyperkalemia
- hypokalemia
- hyperthyroidism
- hypothyroidism
In pharmacokinetics related to inhaled anesthetics, how is the agent absorbed by the body?(Absorption)
uptake from alveoli to pulmonary blood
In pharmacokinetics related to inhaled anesthetics, how is the agent distributed by the body?(Distribution)
to CNS, VRG, Skeletal muscle, fat
In pharmacokinetics related to inhaled anesthetics, how is the agent metabolized by the body?(Metabolism)
variable % metabolism of the volatile agents, associated with how long each specific volatile agent stays in the body
In pharmacokinetics related to inhaled anesthetics, how is the agent eliminate by the body?(Elimination)
Lung primary site for elimination, metabolism plays a very small role in drug elimination
What are 6 factors that will alter the pharmacokinetics of volatile agents?
- low lean body mass
- high % body fat
- volume distribution
- low hepatic function
- low pulmonary gas exchange(lung disease)
- low cardiac output(cardiac disease)
What is the pathway that volatile follows as it enters the body, and what propels this motion?
- anesthesia machine—>alveoli—>capillaries—>cell membranes—>
- partial pressure gradients
- Brain, blood, and all other tissues equilibrate with partial pressures of inhaled anesthetics
What is meant by the phrase volatile agent equilibration?
the same partial pressure exist in both places for example, iDes%=eDes% or Pa=PA(arterial partial pressure=alveolar partial pressure) alveolar {} = end tidal {} = brain {}
Why might you more likely to equilibrate with desflurane as opposed to isoflurane?
because the difference in their BGP
What is the equilibration between alveoli, arterial blood and brain?
PA(alveolar partial pressure) = Pa(arterial partial pressure) = Pbr(brain partial pressures)
PA and Pbr is determined by two factors
- Input
2. Uptake
What are four factors associated with input of anesthetic agents as related to deliver of VA?
- PI-inhaled partial pressures
- alveolar ventilation
- delivery system
- FRC-lung function
What are the three factors associated with uptake of anesthetic agents as related to delivery of VA?
- anesthetic solubility in tissue-BGPC(blood gas partition coefficient, the lower the BGPC the quicker asleep, the quicker awake)
- cardiac output and cerebral blood flow(lower CO the quicker you go to sleep because of slower blood flow, the amount of VA/alveolar concentration goes up due to slower blood flow, lower CO
- alveolar to venous partial pressure differences(A-vD)
alveolar {} = brain {}
Why do inhaled partial pressures of VA need to be high during the initial phase of anesthesia?
- high initial partial pressures offset impact of uptake
- accelerates induction by increasing rate of rise of PA
- as uptake rate decreases, PI may be decreased
turning flows and VA {} at the start of the case to get the patient anesthetized
