Anesthesia

Front 1

Laminar Flow

Back 1

Smooth and orderly. Flow is fastest in the center.

Front 2

Turbulent Flow

Back 2

Eddies, Flow is the same across the diameter of the tube. Resistance is proportional to the square of the flow rate.

Front 3

Generalized Turbulent Flow

Back 3

When the flow through a tube passes the "critical value"

Front 4

Localized Turbulent Flow

Back 4

When the gas flow is below the critical value but meets curve, bends, etc.

Front 5

Compliance

Back 5

It is a measure of distensibility.(ml/cm H2O)

Front 6

Rebreathing

Back 6

To inhale previously respired gases from which carbon dioxide may or may not have been removed.

Front 7

Fresh Gas Flow

Back 7

The amount of rebreathing varies inversely with the total fresh gas flow. If the volume of gas supplied per minute is equal to or greater than the patients
minute volume there will be no rebreathing as long as scavenging system. If less, some rebreathing.

Front 8

Mechanical Dead Space

Back 8

Is the volume in a breathing system occupied by gases that are rebreathed without any change in composition.

Front 9

Physiological Dead Space

Back 9

Anatomical dead space , consisting of patients conducting airway down to the aveoli, and (b) alveolar dead space, which is the volume of alveoli ventilated but not perfused.

Front 10

Designs of the Breathing System

Back 10

The Circle System and Mapleson Breathing System

Front 11

Effects of rebreathing

Back 11

With no rebreathing the composition of inspired gas is identical to that of the fresh gas delivered by the anesthesia machine. With rebreathing, the inspired gas is composed partly of fresh gas partly of rebreathed gas

Front 12

Heat and Moisture Retention

Back 12

Fresh gas from the anesthesia machine is dry and at room temperature. Exhaled gases are warm and saturated with moisture. Rebreathing reduces heat and moisture loss from patient. In most breathing systems, heat is rapidly lost to atmosphere, and gas that is reinhaled has a lower temperature and moisture content than exhaled gas.

Front 13

Altered Inspired Gas Tension

Back 13

The effects of rebreathing on inspired gas tensions will depend on what parts of the exhaled gases are rebreathed and whether these pass to the alveoli (and so influence gas exchange) or only to the anatomical dead space.

Front 14

Oxygen

Back 14

Rebreathing alveolar gas will cause a reduction in the inspired oxygen tension

Front 15

Carbon Dioxide

Back 15

Rebreathing alveolar gas will cause an increased inspired carbon dioxide tension unless the gas passes through an absorbent before being rebreathed

Front 16

Inhaled Anesthetic Agents

Back 16

Rebreathing alveolar gas exerts a "cushioning" effect on changes in inspired gas compostion with alterations in fresh gas composition. During induction when alveolar tensions are lower than those in fresh gas flow, rebreathing alveolar has will reduce the inspired tension and prolong induction. During recovery, the alveolar tension exceed that of the inspired gases, and rebreathing slows agent elimination.

Front 17

Descrepancy between Inspired and Delivered Volumes

Back 17

The volume of gas discharged by a ventilator or reservoir bag usually differs from that which enters the patient. The volume actually inspired may be less or greater than that delivered.

Front 18

Causes of increased inspired Volume

Back 18

When a ventilator is in use, if the FGF > absorption of gas by patient or rate of loss via leaks, it is possible that the FGF might be actually added to the prescribed tidal volume.

Front 19

Causes of Decreased Inspired Volume

Back 19

Wasted Venitilation-Decrease in TV will result from gas compression and distension of breathing system components during inspiration. Loss of compliance (e.g., 14ml/cm H2O)

Examples: Increased Gas Flows, I:E ratios, and lower respiratory rates.

Front 20

Breathing system Leaks

Back 20

TV decreases with leaks. Leaks between the volume sensor located at the patient port and patient can be detected by comparing the inspired and exhaled tidal volumes. Significant leak volume will be less than the inspired volume.

Front 21

Absorber

Back 21

Canisters, housing baffles, side/center tube, bypass

Front 22

Absorber

Back 22

Assembly consists of two breathing tubes and a fresh gas inlet. May include inspiratory and exporatory unidirectional valves, an adjustable APL valve.