Anesthesia Flashcards
What drugs should be avoided in severe respiratory patients?
Alpha-2 -> Respiratory depression
Beta blockers -> don’t use with pneumothorax patients
Avoid high spinal epidurals
In a patient on a ventilator with pleuritis, what pressures should you not exceed?
Pressure should be less than or equal to 10cm H20
What are concerns of reintroducing negative pleural pressure too quickly with a patient that has chronic atelectasis?
Re-expansion pulmonary edema
What patients should be on a non-rebreathing system?
Tobias says <5kg; Lumb/Jones says <10kg (ideally 3-7kg)
What general steps occur when the CO2 absorbs in the rebreathing system?
Absorbent contains various concentrations of Ca(OH)2 and CO2 + hydroxides -> carbonic acid -> H2O + CaCO2
What is the flow rate formula for a rebreathing system?
10x BW (kg) ^0.75 = 3-6 mL/kg/min
What is the recommended flow rate for a non-rebreathing system?
3x patient’s minute volume (MV = RR x TV)
~200-300 mL/kg needed to prevent rebreathing
What are the phases of the waveform on end-tidal CO2 monitors?
0: fresh gas passes sensor
1: CO2 from lungs passes sensor, elevating waveform
2: Plateau once mixing of dead space gas
3: Waveform peaks during end of expiration
4: Inspiration draws fresh gas over sensor, waveform drops to baseline
Draw how an end tidal CO2 waveform would change in the following situations:
1. Hypoventilation
2. Hyperventilation
3. Rebreathing CO2
4. Leak in circuit
- Increase in height of plateau
- Decrease in height of plateau
- The waveform does not return to zero/baseline at inspiration
- “Sail” shaped end to waveform vs nice plateaus with sharp drop at inspiration
What nerve blocks are available for dental procedures?
Mental
Inferior alveolar
Infraorbital
Maxillary
What dose of bupivicaine do you use in dogs vs cats?
2.5mg/kg dog
1mg/kg cats
What induction agents can increase intraocular pressures?
Ketamine and propofol
What are the heat exchange mechanisms in anesthetized patients?
Evaporation= lungs/feet
Conductive = cold surfaces, water washing
Radiation = loss of infrared energy
What is the most effective method of warming anesthetized patients?
Forced warm air
Normal CVP with monometer?
With transducer?
0-8cm H2O
0-5mmHg
What are four methods of nonivasive cardiac output monitoring and describe how performed?
- Thermodilution (themometer tipped pulmonary catheter / inject saline at known temp -> AOC of temp change is CO)
- Lithium dilution (inject Li venous, aspirate from arterial)
- Pulse contour analysis (arterial BP waveform after calibration via Lithioum or thermo)
- Noninvasive CO (uses CO2 to estimate O2 consumption via Fick principle).
How does the pulseOx calculate SpO2?
What HCT level will cause changes in SpO2 on pulseOx?
What are common causes of inaccurate SpO2 readings?
Calculates by Hb absorbtion within the arterial pulsatile component of the path the light travels.
HCT <10%
Vasoconstriction/lowCO, hypothermia, pain, alpha-2 agonists
How does uremia make catheters problematic?
What drugs should be used with caution as pre-med/induction in renal dz patients?
What local block should be avoided?
What can be given to dogs with poor urine output to improve urine flow?
Uremia impairs platelet function.
- Alpha-2s increase urine output so don’t use in obstructions.
- ketamine is excreted unchanged in cat urine
Avoid epidurals because of the possibility of platelet dysfunction/hemorrhage
Mannitol, furosemide, dopamine to increase flow
When heart failure occurs, what 2 neurohormonal changes occur that affect anesthesia?
Body activates the RAAS -> fluid retention and hypervolemia; also upregulates the sympathetic NS
What are anesthetic monitoring changes seen with air embolus?
Sudden decrease in ETCO2, drop in BP and pulseOx, +/- audible “washing machine” murmur
What induction drug should be avoided in thyroid patients, especially hyperthyroid?
Ketamine because may have concurrent heart disease and because it can induce a thyroid storm
What 3 drugs can be given to patients with insulinomas while under anesthesia?
-Glucocorticoids (promote insulin resistance and gluconeogenesis)
-Glucagon to normalize BG 5-13mg/kg/min
- alpha-2s increase insulin resistance
What drugs should be available for emergency surgeries on the biliary tree?
Which opioids are best for premed of liver patients? Why?
Which induction agent is best for liver?
Anticholinergics because can have increased vagal tone
Morphine, hydromorphone, oxymorphone -> don’t need P450 for clearance and don’t accumulate in tissues
Propofol has extrahepatic sites for metabolism +/- ket/midaz
What is absorbtion atelectasis?
Alveolar collapse when O2 replaces N volume then is rapidly absorbed -> no more volume to hold open
What causes malignant hyperthermia?
What do you treat with?
Defect in ryanodine receptor (Ca++ release)
Dantrolene to decrease Ca release