Anesthesia Flashcards
Methods to initiate and maintain a steady state concentration of drug
Loading dose + CRI maintenance
OR
Infusion at maintenance, build up over time
Toxic doses of lidocaine (dogs vs cats)
Dogs >8mg/kg
Cats >6mg/kg
Upper airways (nasal cavity, pharynx, larynx) contribute to what % of total airway resistance?
50%
What perioperative period has the highest incidence of mortality?
Early recovery period
Why are changes in PaCO2 easily detected by central chemoreceptors over changes in PaO2?
CO2 readily diffuses into CSF and chemoreceptor cells
Where are peripheral chemoreceptors located?
carotid and aortic bodies
PEEP
Positive end-expiratory pressure (PEEP)
- adds pressure to the lungs at the end of each breath, which helps reinflate collapsed areas.
- can increase functional residual capacity (FRC) and prevent airway collapse
Difference in rebreathing vs non-rebreathing systems in elimination of CO2
Rebreathing system - uses
CO2 absorbent to remove from system
Nonrebreathing system - utilizes high fresh gas flow to prevent rebreathing of CO2
What are the primary effects of the RAAS?
Increase systemic vascular resistance (BP)
Intravascular fluid retention
Promote hypervolemia
Decreased water excretion
How does myxomatous degenerative valve disease affect cardiac output?
decreased stroke volume with each regurgitation = decreased cardiac output
What anesthesia monitoring tool may allow early detection of pulmonary crackles in pulmonary edema (of CHF)?
Esophageal stethoscope
Recommended surgical IVF rate for patients with cardiac disease
2-5ml/kg/hr
What induction drug creates the least degree of cardiovascular depression?
Etomidate
Branham reflex
Associated with ligature of a PDA - reflexive decrease in heart rate due to abrupt increase in afterload
T/F - Patients with traumatic pneumothorax should have emergent surgery
False. May also have pulmonary contusions, which may take days to reveal
Hypoxic pulmonary vasoconstriction (HPV)
Physiological response that occurs when small pulmonary arteries narrow in response to low oxygen levels in the alveoli
Benefits:
Helps to direct blood to areas of the lungs with more oxygen, which improves gas exchange (V/Q matching) and oxygen delivery
Reducing blood flow to nonventilated lungs - e.g. one-lung anesthesia, HPV can reduce blood flow to the lung that isn’t being ventilated. helps to prevent hypoxemia and excessive bleeding in the lung that’s being operated on
PCV below what % may compromise oxygen delivery (incl in chronic disease)
<20%
Primary risk with rapid administration of antibiotics?
Hypotension (mechanism unknown)
What drug cannot be administered intravenously concurrent with cefazolin?
Lidocaine
What is the most important factor in determining the potency and onset of action of local anesthetics? (what are the other factors)
lipid solubility
(% protein binding, pKa)
Which local anesthetic has the highest potency for CNS toxicity?
bupivacaine
Duration of action - lidocaine
45-60 minutes
Lidocaine vs bupivacaine (potency, onset, duration of action, lipid solubility)
Lidocaine - less potent, quicker onset, shorter duration of action (<1hr), less lipid soluble
Bupivacaine - 4x more potent, slow onset (20-30min), longer duration of action (3-10hrs), more lipid soluble
Toxicity effects of local anesthetics
CNS, then cardiac toxicity - at high plasma concentrations (e.g. from indirect IV injection)
