ANEO+5801+Solubility+and+Vaporizers+PowerPoint

GAS VS. VAPOR

A vapor is the gas phase of a substance that exists as a liquid or solid at room temperature; a gas is a substance that exists only in its gas phase at room temperature.

SOLUBILITY

Describes the number of moles or millimoles of a solute that dissolve in 1 liter of a given solvent.

Henry’s Law

At a certain temperature, the amount of gas dissolved in a given liquid is directly proportional to the partial pressure of the gas in equilibrium with the liquid.

Bunson Solubility Coefficient

Volume of gas at a certain temperature and 1 atm that dissolves in unit volume of liquid.

Ostwald Solubility Coefficient

Volume of gas dissolved in 1 unit volume of a liquid at a certain temperature, independent of pressure.

Partition Coefficient

The ratio of the amount of substance present in one phase compared with another, in equal volume and equilibrium.

Diffusion

The process by which molecules of a substance transfer through a layer or area such as the surface of a solution or tissue.

Fick’s Law

The rate of diffusion is proportional to the concentration gradient.

Osmosis

Fluid shifts in order to accommodate the concentration gradient.

Vapor Pressure

Saturated vapor pressure (SVP): the partial pressure of an agent in vapor phase, independent of barometric pressure, dependent on the agent and temperature.

Boiling Point

The temperature at which saturated vapor pressure equals atmospheric pressure.

Saturated Vapor Pressure (SVP)

The pressure exerted by the gas phase on the walls of the container at constant temperature and equilibrium.

Vapor Concentration

Volume % of anesthetic calculated as (saturated partial pressure of volatile anesthetic/atm pressure) x 100.

Variable Bypass Vaporizers

Vaporizers with an adjustable proportion of gas that either enters or bypasses a vaporizing chamber.

Measured Flow Vaporizers

Vaporizers that add vapor directly to the fresh gas flow.

N2O

Nitrous Oxide, an anesthetic agent with various solubility coefficients.

Halothane

An anesthetic agent with a blood solubility coefficient of 2.3.

Isoflurane

An anesthetic agent with a boiling point of 48.5 °C.

Sevoflurane

An anesthetic agent with a boiling point of 58.5 °C.

Enflurane

An anesthetic agent with a boiling point of 56.5 °C.

Desflurane

An anesthetic agent with a boiling point of 22.8 °C.

MAC

Minimum alveolar concentration: the concentration of anesthetic required to prevent movement in 50% of subjects in response to surgical stimuli.

Vaporizer Safety Features

Interlock system, concentration dial, and port valves designed to mitigate hazards.

Pumping Effect

Increase in vaporizer output due to back pressure during positive pressure ventilation.

Temperature Compensation

Adjustments made in vaporizers to account for variations in temperature affecting vapor output.

Flow Extremes

Conditions that can lead to decreased output in vaporizers due to insufficient pressure or mixing of vapor.

Atmospheric Pressure Changes

Variations in local barometric pressure affecting maximum agent concentration.

Agent Specific Calibration

Vaporizers calibrated specifically for certain anesthetic agents.

Thermal Conductivity

A physical property affecting vaporization efficiency in vaporizers.

Control Alarm

A safety feature in vaporizers indicating issues such as low agent levels.

Calibration

The process of adjusting vaporizers for specific substances to ensure accurate delivery.

Interlock Malfunction

Failure of safety measures that can lead to incorrect dosing of anesthetic.

High SVP

A characteristic of anesthetic agents that dissolve readily in the vapor phase, typically leading to high volatility.

Low SVP

A characteristic of anesthetic agents that do not readily vaporize under standard conditions.

Tipping of Vaporizer

An error that could lead to leakage or incorrect dosing of an anesthetic agent.

Overfilling of Vaporizer

A hazard that can occur with key filler systems, risking overdose of anesthetic.

Gas Type

Factors affecting solubility that differentiate various gases like N2 and N2O.

Liquid Type

Factors affecting solubility that consider the solvent's properties, for example, blood.

Concentration Dial

User-controlled setting that indicates the desired output concentration of anesthetic.

Agent Enriched Gas

Gas enriched with anesthetic agent ready for patient delivery.

Pressurizing Effect

Increased internal pressure in a vaporizer contributing to unpredictable output.

Vaporizer Manifold

Component of the vaporizer system ensuring fluid pathways for gas and vapor.

Dilution Method

Process for achieving clinically useful concentrations of anesthetic agents.

Bubble Through Method

Vaporizer method where carrier gas bubbles through the liquid anesthetic.

Flow-Over Method

Vaporizer method where gas flows over the surface of the liquid anesthetic.

Thermocompensation

Mechanism ensuring consistent output from vaporizers with temperature changes.

Anesthetic Agent Color Code

Color system used to identify different anesthetic agents for safety.

Locking Lever

Safety feature that prevents accidental adjustment of vaporizer settings.

Liquid Level Operational Sight Glass

Indicator that shows the current liquid level in a vaporizer.

Control Dial Alarm

Alarm that alerts the operator to maintain safe operation levels.

Key-Fill System

A method for refilling vaporizers that prevents cross-contamination.

Dilution of Anesthetic

The process of mixing anesthetic gas with fresh gas to achieve desired concentrations.

Interior Pressure Regulation

Control of pressure within the vaporizer's chamber for consistent dosing.

Max Concentration Calculation

Formula to determine the maximum allowable concentration of anesthetic based on SVP and barometric pressure.

Concentration Calibration

Measurement of output of a vaporizer against the desired concentration.

Saturation Conditions

State in which the vapor concentration is maximized for a specific anesthetic.

Volume % Calculation

A method to express the concentration of anesthetics in vapor form.

Control Mechanism

The system used to manage and regulate the output of anesthetic vaporizers.

Agent Specific Fill Caps

Caps designed to fit only the corresponding anesthetic agent, preventing misuse.

Flow Over Flowmeters

Measurement devices used to monitor the flow of gas in vaporizer systems.

Variable Resistance System

System in vaporizers that allows for adjustments to the flow of carrier gases.

Fresh Gas Flow

The introduction of fresh carrier gas into the anesthesia delivery system.

Safety Features

Built-in mechanisms designed to improve the operational safety of vaporizers.

Calibration Error

Errors in setting vaporizers that can lead to inadequate or excessive doses.

Vaporizer Output Calculation

Process of determining the actual output of anesthetic from a vaporizer based on its settings.

Flow Rate Impact

Significance of gas flow rates on the performance of vaporizers.

Patient Safety Mechanisms

Preventive strategies employed within vaporizers to protect patient outcomes.

Locking Gas Bypasses

Mechanisms that secure vaporizer settings against accidental changes.

Gas Outlet

Exit point for anesthetic gases from the delivery system to the patient.

Second-stage Pressure Regulator

Device that controls the pressure of the gas supplied to the anesthesia machine.

Anesthesia Delivery System

Comprehensive setup used for administering anesthetics during procedures.

Helium Flowmeter

A device used for measuring and controlling helium flow in anesthetic systems.

Back Pressure Effects

Changes in concentration of vapor due to pressure fluctuations during positive pressure ventilation.

What does Fick’s Law state about diffusion?

The rate of diffusion is proportional to the concentration gradient.

What is the definition of osmosis?

Fluid shifts in order to accommodate the concentration gradient.

What is the effect of high saturated vapor pressure (SVP)?

It indicates anesthetic agents that dissolve readily in the vapor phase, leading to high volatility.

What characterizes a Low SVP anesthetic agent?

It does not readily vaporize under standard conditions.

What is meant by agent-specific calibration in vaporizers?

Vaporizers calibrated specifically for certain anesthetic agents.

What is the purpose of the concentration dial on a vaporizer?

It indicates the desired output concentration of anesthetic.

How does the temperature compensation feature work in vaporizers?

Adjustments are made to account for variations in temperature affecting vapor output.

What is a bubble through method?

A method where carrier gas bubbles through the liquid anesthetic.

What is the locking lever's purpose in a vaporizer?

To prevent accidental adjustment of vaporizer settings.

What does the term 'flow extremes' refer to in vaporizers?

Conditions leading to decreased output due to insufficient pressure or mixing.

What is the importance of the fresh gas flow in anesthesia delivery?

It's the introduction of fresh carrier gas into the anesthesia delivery system.

What is the role of control alarms in vaporizers?

They indicate issues such as low agent levels.

What does the partition coefficient describe?

The ratio of the amount of substance present in one phase compared to another at equilibrium.

What defines the boiling point of a substance?

The temperature at which saturated vapor pressure equals atmospheric pressure.

What is the main principle behind Henry’s Law?

The amount of gas dissolved in a liquid is proportional to the gas's partial pressure.

What might cause an interlock malfunction in a vaporizer?

Failure of safety measures which may lead to incorrect dosing.

What does the term 'thermal conductivity' refer to in vaporization?

A property affecting vaporization efficiency in vaporizers.

What is the primary purpose of the vaporizer manifold?

To ensure fluid pathways for gas and vapor.

What characteristic does a nitrous oxide (N2O) have?

It is an anesthetic agent with various solubility coefficients.

Why is calibration important for vaporizers?

It ensures accurate delivery of anesthetic substances.

What does the control mechanism in vaporizers do?

Regulates the output of anesthetic vaporizers.

What happens during the pumping effect in vaporizers?

Increase in vaporizer output due to back pressure during ventilation.

What is represented by vapor concentration?

The volume % of anesthetic calculated based on its saturated partial pressure.

What is the function of agent enriched gas?

Gas enriched with anesthetic agent ready for patient delivery.

What is significant about the back pressure effects in positive pressure ventilation?

They affect vapor concentration due to pressure fluctuations.

What does the dilution method achieve in anesthetic delivery?

It achieves clinically useful concentrations of anesthetic agents.

What does the control alarm indicate?

It alerts the operator to maintain safe operation levels.