Dr. Adarsh Kumar Associate Professor Department of Surgery and RadiologyDGCN COVAS, CSKHPKV, Palampur (India)andFaculty of Veterinary Medicine, Al Fateh University, Tripoli, Libya : Dr. Adarsh Kumar Associate Professor Department of Surgery and RadiologyDGCN COVAS, CSKHPKV, Palampur (India)andFaculty of Veterinary Medicine, Al Fateh University, Tripoli, Libya INHALANT ANESTHETIC EQUIPMENT AND BREATHING CIRCUITS The High Pressure System : The High Pressure System The Fresh Gas Source
Oxygen is used for two reasons: Firstly, it is vital for the life of the patient and secondly it is used to vaporize the volatile anesthetic agent and deliver it to the patient.. Cylinders : Cylinders fitted with a number of safety features because of the dangerously high pressures they hold, and to avoid the wrong cylinder being fitted to the yoke of the anesthetic machine.
Tag Label indicates whether the cylinder is full, part full or empty. Slide 7: Color code system for gas cylinders:
Oxygen: Grey/black with white top.
Carbon dioxide: Grey/black
N2O: Light or sky blue.
Pin index system: “American Standard Connection No. 860 pin index safety system.” Small Bank of Cylinders : Small Bank of Cylinders RsCr 220 8 Pin Index System : Pin Index System Pin Index Numbering : Pin Index Numbering Slide 11: The primary purpose of the anesthetic machine and system is to deliver an inhaled (gas) anesthetic to the animal to keep him unconscious through surgery
There are two basic types of anesthetic systems used for small animals:
Nonrebreathing. REBREATHING SYSTEM : REBREATHING SYSTEM Rebreathing systems are used for animals weighing over 10 pounds.
Rebreathing system allows recirculation of exhaled gases to the animal.
Each breath contains exhaled gas that has had the carbon dioxide removed and fresh oxygen and anesthetic added. REBREATHING SYSTEM : REBREATHING SYSTEM Slide 14: A. Oxygen source with pressure gauge - Oxygen is supplied to the animal. It also is the carrier gas that brings the inhaled anesthetic to the pet.
B. Pressure reducing valve - This valve decreases the high pressure from the oxygen tank to a usable level.
C. Flowmeter - This allows the anesthetist to determine the rate the oxygen will flow to the animal. Slide 16: D. Oxygen flush valve - This valve allows oxygen to flow directly to the animal bypassing the anesthesia. This is done at the end of the anesthesia or if the animal is at too deep of a plane of anesthesia during the surgery.
E. Vaporizer - The vaporizer converts the liquid anesthetic to a gas state and adds controlled amounts of the gas anesthetic to the oxygen that is flowing through the machine. Slide 17: F. Inhalation valve - This allows the gases to flow only to the animal and not back to the vaporizer, by way of a one-way valve.
G. Inhalation hose - This hose carries the gases to the animal.
H. Connecting port - The rebreathing system has a Y piece which connects the inhalation hose, endotracheal tube, and exhalation hose. Slide 18: I. Endotracheal tube - This tube is placed into the animal's trachea (windpipe) to allow the oxygen and gases to be breathed into the lungs.
J. Exhalation hose - This hose carries the gases the animal breathed out back to the anesthetic machine.
K. Exhalation valve - This allows the exhaled gases to flow only into the anesthetic machine, not back to the animal, by way of a one-way valve. Slide 19: L. Rebreathing (reservoir) bag - This is an inflatable rubber bag which allows the accumulation of fresh and expired gas during exhalation so that a reservoir of gas is available for the next breath.
The bag also acts as a safety device to prevent rapid pressure increases in the system. It can be manually squeezed to 'bag' an animal as needed during surgery to assist breathing. Slide 20: M. Pop-off valve - This is a pressure relief valve that allows the release of waste gases and extra pressure from the system into the scavenger hose.
N. Scavenger hose - This hose carries waste gases (e.g., oxygen, nitrous oxide, inhalation anesthetic, and carbon dioxide) out of the system and out of the building.
. Slide 21: O. CO2 absorber canister - Any gases that do exit through the pop-off valve pass through the carbon dioxide absorber before returning to the animal. The chemicals ( soda Lyme) in the container remove carbon dioxide from the gases that pass through it. NONREBREATHING SYSTEM : NONREBREATHING SYSTEM The nonrebreathing system is used for those animals that are typically under about 10 pounds.
These smaller animals need a higher flow of gases to prevent rebreathing of carbon dioxide.
this type of system, little or no exhaled gases are returned to the animal, but exit through the pop-off valve into the scavenger hose.
A nonrebreathing system is usually not used in the larger pets, since the high gas flow wastes oxygen and anesthetic.
High flow rates also lead to heat and fluid loss from the pet.
Heated and humidified exhaled gases are replaced in the respiratory system by an inspired gas mixture that is cool and dry. NONREBREATHING SYSTEM : NONREBREATHING SYSTEM Slide 24: The first three parts are the same as with the rebreathing system.
A.Oxygen source with pressure gauge
B. Pressure reducing valve
C. Flowmeter Slide 25: E. Vaporizer - The vaporizer converts the liquid anesthetic to a gas state and adds controlled amounts of the gas anesthetic to the oxygen that is flowing through the machine.
G. Inhalation hose - The gases exit the vaporizer and go directly into a hose for delivery to the animal. Slide 26: H. Connecting port - This connects the inhalation and exhalation hoses to the endotracheal tube.
I. Endotracheal tube - This tube is placed into the animal's trachea to allow the oxygen and gases to be breathed into the lungs.
J. Exhalation hose - Exhaled gases pass through this tube directly to the reservoir bag. Slide 27: L. Rebreathing (reservoir) bag - Exhaled gases pass into the reservoir bag.
M. Pop-off valve - This is a pressure relief valve that allows the release of waste gases and extra pressure from the system into the scavenger hose. Slide 28: N. Scavenger hose - Exhaled gases pass from the reservoir bag and out of the system (and building) through the scavenger hose. Comparison : Comparison firstname.lastname@example.org : email@example.com THANK YOU