Morgan and Mikhail's Clinical Anesthesia Flashcards

Study Notes

CO2 Absorber Systems

Color conversion of pH indicator dye (e.g., ethyl violet) signals absorbent exhaustion, which should be replaced when 50-70% has changed color.
Hydroxide salts are irritating to skin and mucous membranes.
Increasing soda lime hardness by adding silica minimizes risk of sodium hydroxide dust inhalation and decreases gas flow resistance.
Absorbent granules can absorb and release volatile anesthetics, contributing to delayed induction or emergence.
Dry soda lime is more likely to absorb and degrade volatile anesthetics.
Volatile anesthetics can be broken down to carbon monoxide by dry absorbent (e.g., sodium or potassium hydroxide).
Desflurane is most susceptible to carbon monoxide formation.
Compound A is a byproduct of sevoflurane degradation by absorbent and is nephrotoxic in animal models.

The Anesthesia Machine

Basic components: pressure regulators, vaporizers, breathing circuit, mechanical ventilator, manual (bag) ventilator, auxiliary oxygen supply, and suction apparatus.
Gas is supplied from central supply through piping network and smaller gas cylinders (E-cylinders) on the machine.
Machine has O2 analyzers and spirometers.

O2 Analyzers and Spirometers

O2 analyzer is vital for safe delivery of general anesthesia.
Three types of O2 analyzers: polarographic (Clark electrode), galvanic (fuel cell), and paramagnetic.
Paramagnetic analyzers are more expensive, self-calibrating, and have no consumable parts.
Sensor should be placed in inspiratory or expiratory limb of breathing circuit, not in fresh gas line.
Expiratory limb has slightly lower oxygen partial pressure than inspiratory limb due to patient's oxygen consumption.
Spirometers measure tidal volumes and are located in the expiratory limb of the breathing circuit.
Some machines have an additional spirometer that measures inspiratory tidal volumes.

Cardiovascular Monitoring

Noninvasive arterial blood pressure monitoring techniques: oscillometry and arterial tonometry.
Oscillometry: arterial pulsations cause small oscillations in cuff pressure when cuff is inflated above SBP.
Maximal oscillation occurs at MAP, after which oscillations decrease.
Automated BP monitors derive SBP, MAP, and DBP after electronically measuring pressures at which oscillation amplitudes change.
Limitations of oscillometry: unreliable during arrhythmias and cardiopulmonary bypass.
Arterial tonometry: beat-to-beat BP is sensed by pressure required to partially flatten the artery.
Limitations of tonometry: movement artifact and need for frequent calibrations.

Invasive Arterial Blood Pressure Monitoring

Indications: induced hypotension, anticipated wide blood pressure swings, end-organ disease, and need for multiple arterial blood samples.
Contraindications: catheterization should be avoided in arteries of extremities with inadequate collateral blood flow or suspicion of vascular insufficiency.
Selection of artery for cannulation: radial artery is commonly used due to its superficial location and collateral blood flow.
Ulnar artery: deeper and more tortuous than radial artery, with risk of inadequate collateral flow.
Assessment of ulnar collateral circulation adequacy: Allen test, palpation, Doppler probe, plethysmography, or pulse oximetry.

Description

This quiz is based on Morgan and Mikhail's Clinical Anesthesia Flashcards, covering anesthesia-related topics and concepts. It's a great resource for medical students and professionals. Test your knowledge of anesthesia principles and practices.