Anesthesia Machine Lab Report
To effectively perform or assist with a procedure, you must fully understand the anesthesia machine. It’s important to not only identify, but correctly and efficiently operate each of the machine’s components. In addition, you must understand the gas flow through the system, how to perform a pre-anesthetic check, also known as a pressure check, and how to care for and maintain this equipment. I will focus on a circle rebreathing system, it’s also the most common system. It contains a compressed gas supply, the anesthesia machine itself, and the breathing circuit. First, I will identify the machine as a whole system. The anesthetic machine’s function is to deliver volatile anesthetic gas to and from the patient. We need the combination of the compressed gas supply, breathing circuit, and the other machine parts to work together. The gas supply comes from the compressed gas cylinder and/or the tank. The tank has a pressure gauge and is held in a steal or aluminum cylinder. These tanks are flammable and supplied under extreme pressure, approximately 2200 psi, with varying volumes depending on the type of anesthesia machines we use. They attach to
…show more content…
the machine via the yoke. Each yoke is made specifically for each type of gas being used by a pin-index system, which means that the pins on the yoke will only work with the holes specifically positioned on the valve of the cylinder. This prevents incorrect gas connection. Some machines have nitrous oxide tanks. Some provide analgesia allowing for less anesthetic agents to be used. Oxygen must be used with these machines, because it is essential for respirations. Tanks are identified by color. For example, a green tank means an oxygen tank. Now, I will discuss the parts to the machine, starting from the attachment to the compressed gas supply and ending with the scavenger system. Once the gas is open or on from the cylinder, the pressure reducing valve takes the high-pressure gas and turns it into a low pressure to be inhaled by the patient. It then enters the green low-pressure hose where the oxygen can reach the oxygen flow meter or the oxygen flush valve. The flow meter controls the amount of oxygen reduced from the pressure reducing valve and the oxygen hose, but will not allow air into the system until turned on. We measure the flow rate by a tapered glass tube with a ball or bobbin floating on the stream of moving gas. The higher the gas flow, the higher the bobbin or ball will go in the tube. The should read between four and seven mL/kg/min. The flow meter then sends oxygen to the vaporizer, anesthetic gas is picked up here. The vaporizer is possibly the most important part of the machine because it delivers the anesthetic material. We use a precision vaporizer because it is insulated making sure the temperature, gas flow rate, and back pressure cannot affect its function. The anesthetic liquid in the vaporizer should be half full at all times. The vaporizer’s job then converts the liquid anesthetic in the machine to a vapor state. A controlled amount gets sent with the carrier gas to the inhalation valve. If we don’t need anesthetic gases or rapid administration of just oxygen, we press the oxygen flush valve. It can deliver and not return. It is important to know that we must NEVER push the oxygen flush valve when there is a non-rebreathing circuit being used or the pop-off valve is closed. The vaporizer sends the oxygen and anesthetic vapor to the inhalation valve. This valve connects to the inhalation tube which has a Y-piece that connects to the endotracheal tube in the patient. It also attaches to the exhalation tube to the expiratory valve. The exhalation and inhalation tubes are made of corrugated black rubber, neoprene, or plastic, they should also be wider than the ET tube. The expiratory valve can only take air away from the patient. The inhalation valve can only take in fresh gas or recycled/” rebreathed” air into the patient. Once air has been expired it goes into the reservoir bag. The bag is an inflatable rubber bag that inflates when gas enters and deflates as the patient breathes air in. The bag does the opposite that the patient does. As it stores the gas, it allows us to monitor the rate and depth of respirations and allows us to “bag the patient.” The stored gas is easier for patients to breathe. If it isn’t properly inflating or deflating, we know something is wrong with the machine. We chose the size of the bag, by multiplying the tidal volume by 5, then go with the next size up. After the expired air has reached the reservoir bag, it can be released from the pop-off valve into the scavenger system or absorbed into the carbon dioxide absorber, which is made of granules that absorb the carbon dioxide and produce water and carbonate that can be rebreathed and is sent back into the inhalation valve. Remember to change the granules before they are depleted. When air isn’t rebreathed, it goes to the pop-off valve, the pop-off valve is the place where excessive pressure is released. The main purpose of the pop-off valve is for the escape of excess gas, and is extremely important. This valve should be open at all time. The only exception is when doing a pressure check or giving a breath. It should then be immediately opened following the set of breaths. A blue scavenger tube is hooked to the pop-off valve. The tube and charcoal canister make up the scavenger system. The scavenger system’s important role is to take waste anesthesia gases and absorb them into the charcoal canister. It’s important to keep the absorber canister on the ground so gravity will pull the waste anesthesia gases down into it. It can be on its side or kept elevated from the floor. The canister has to be monitored and replaced when necessary. Lastly, I have the pressure manometer. It can be placed anywhere in the system and is a pressure gauge attached to the breathing circuit. It should measure 20 cmH₂O for small animals and 30 cmH₂O for large animals. We can measure this when we do our pressure check of the machine. Now I can trace the flow of the different gases. Using the circle rebreathing system, I will start with the flow of oxygen. It starts at high pressure in the compressed cylinder attached to the machine via the yoke. The oxygen goes through the pressure reducing valve where it is decreased to 45-50 psi after it’s turned on. The green oxygen tubing then takes the oxygen to the oxygen flow meter, then to the precision vaporizer, where anesthetic gas is mixed in. After they are mixed both gases reach the inhalation valve. Inhalation tubes attached to the inhalation valve take the oxygen and anesthetic gas mixture from the vaporizer to the patient trough the Y-piece that is attached to the patient’s ET tube and the exhalation tube. Expired gas then goes from the exhalation tube to the expiratory valve on the machine into the reservoir bag. Once here, the expired air then can either escape from the pop-off valve into the scavenger system or into the carbon dioxide absorber granules where it’s rebreathed into the inhalation valve and sent back to the patient through the inhalation tube, Y-piece, and ET tube. If you want just oxygen to the patient quickly, we push oxygen flush valve and the low-pressure hose takes the oxygen from the cylinder, through the pressure reducing valve, into the inhalation valve bypassing the vaporizer. Next, I will examine how to make all the parts of the machine function properly, and discuss how to do a pressure check. First, I need to connect the breathing circuit components. I will attach the Y-tube, attached to the inspiratory and expiratory tubes, to the two matching valves. Then, I will attach the rebreathing bag. After this, I will make sure the scavenger system is in place. Once I have done this, I will make sure the oxygen supply is attached and I will turn it on. Then I will verify that I have at least half a tank of anesthetic and close the pop-off. I will then occlude the Y-piece with my thumb so no air can escape. Then I will push the oxygen flush valve until the manometer reads 20 cmH₂O. Then make sure it stays at this point. After this is verified, I will open the pop-off valve and unocclude. If it does not stay at the reading notify an advisor. Now I will discuss the care and maintenance of the anesthesia machine, since I have discussed the components and flow of gas.
Keeping the machine clean and dry is key to proper maintenance. You must change the Humid-vents monthly, they are placed between the ET tubes and the breathing tubes to removes the excess water. They help to keep the exhalation tube dry. Viral filters can be placed between exhalation valve and the exhalation tubes. This filter helps prevent the entrance of viruses into the machine and can be changed every two to three months. The gas cylinders should be inspected by the manufacture that we buy them from. As well as the pressure reducing valve and vaporizer should be inspected by them. Pressure gauges, manometers, flow meters, and flush valves should be checked for accuracy and proper
functioning. If there are ever leaks, we should replace the components that have caused the leaks. Valves can be inspected and cleaned as often as needed, the reservoir bag, breathing tubes, Y-piece, and any other piece should be cleaned after every use. These pieces should be disinfected, rinsed, rinsed and hung up to dry. As long as they are all still working well, these pieces can be reattached and reused. Knowing the functions of every part of the anesthesia machine is very important. Recognizing the pathway of gas from the cylinder to the patient is a key component of anesthesia. Finally, knowing how to pressure check the anesthesia machine is an invaluable skill for you to have.
the machine via the yoke. Each yoke is made specifically for each type of gas being used by a pin-index system, which means that the pins on the yoke will only work with the holes specifically positioned on the valve of the cylinder. This prevents incorrect gas connection. Some machines have nitrous oxide tanks. Some provide analgesia allowing for less anesthetic agents to be used. Oxygen must be used with these machines, because it is essential for respirations. Tanks are identified by color. For example, a green tank means an oxygen tank. Now, I will discuss the parts to the machine, starting from the attachment to the compressed gas supply and ending with the scavenger system. Once the gas is open or on from the cylinder, the pressure reducing valve takes the high-pressure gas and turns it into a low pressure to be inhaled by the patient. It then enters the green low-pressure hose where the oxygen can reach the oxygen flow meter or the oxygen flush valve. The flow meter controls the amount of oxygen reduced from the pressure reducing valve and the oxygen hose, but will not allow air into the system until turned on. We measure the flow rate by a tapered glass tube with a ball or bobbin floating on the stream of moving gas. The higher the gas flow, the higher the bobbin or ball will go in the tube. The should read between four and seven mL/kg/min. The flow meter then sends oxygen to the vaporizer, anesthetic gas is picked up here. The vaporizer is possibly the most important part of the machine because it delivers the anesthetic material. We use a precision vaporizer because it is insulated making sure the temperature, gas flow rate, and back pressure cannot affect its function. The anesthetic liquid in the vaporizer should be half full at all times. The vaporizer’s job then converts the liquid anesthetic in the machine to a vapor state. A controlled amount gets sent with the carrier gas to the inhalation valve. If we don’t need anesthetic gases or rapid administration of just oxygen, we press the oxygen flush valve. It can deliver and not return. It is important to know that we must NEVER push the oxygen flush valve when there is a non-rebreathing circuit being used or the pop-off valve is closed. The vaporizer sends the oxygen and anesthetic vapor to the inhalation valve. This valve connects to the inhalation tube which has a Y-piece that connects to the endotracheal tube in the patient. It also attaches to the exhalation tube to the expiratory valve. The exhalation and inhalation tubes are made of corrugated black rubber, neoprene, or plastic, they should also be wider than the ET tube. The expiratory valve can only take air away from the patient. The inhalation valve can only take in fresh gas or recycled/” rebreathed” air into the patient. Once air has been expired it goes into the reservoir bag. The bag is an inflatable rubber bag that inflates when gas enters and deflates as the patient breathes air in. The bag does the opposite that the patient does. As it stores the gas, it allows us to monitor the rate and depth of respirations and allows us to “bag the patient.” The stored gas is easier for patients to breathe. If it isn’t properly inflating or deflating, we know something is wrong with the machine. We chose the size of the bag, by multiplying the tidal volume by 5, then go with the next size up. After the expired air has reached the reservoir bag, it can be released from the pop-off valve into the scavenger system or absorbed into the carbon dioxide absorber, which is made of granules that absorb the carbon dioxide and produce water and carbonate that can be rebreathed and is sent back into the inhalation valve. Remember to change the granules before they are depleted. When air isn’t rebreathed, it goes to the pop-off valve, the pop-off valve is the place where excessive pressure is released. The main purpose of the pop-off valve is for the escape of excess gas, and is extremely important. This valve should be open at all time. The only exception is when doing a pressure check or giving a breath. It should then be immediately opened following the set of breaths. A blue scavenger tube is hooked to the pop-off valve. The tube and charcoal canister make up the scavenger system. The scavenger system’s important role is to take waste anesthesia gases and absorb them into the charcoal canister. It’s important to keep the absorber canister on the ground so gravity will pull the waste anesthesia gases down into it. It can be on its side or kept elevated from the floor. The canister has to be monitored and replaced when necessary. Lastly, I have the pressure manometer. It can be placed anywhere in the system and is a pressure gauge attached to the breathing circuit. It should measure 20 cmH₂O for small animals and 30 cmH₂O for large animals. We can measure this when we do our pressure check of the machine. Now I can trace the flow of the different gases. Using the circle rebreathing system, I will start with the flow of oxygen. It starts at high pressure in the compressed cylinder attached to the machine via the yoke. The oxygen goes through the pressure reducing valve where it is decreased to 45-50 psi after it’s turned on. The green oxygen tubing then takes the oxygen to the oxygen flow meter, then to the precision vaporizer, where anesthetic gas is mixed in. After they are mixed both gases reach the inhalation valve. Inhalation tubes attached to the inhalation valve take the oxygen and anesthetic gas mixture from the vaporizer to the patient trough the Y-piece that is attached to the patient’s ET tube and the exhalation tube. Expired gas then goes from the exhalation tube to the expiratory valve on the machine into the reservoir bag. Once here, the expired air then can either escape from the pop-off valve into the scavenger system or into the carbon dioxide absorber granules where it’s rebreathed into the inhalation valve and sent back to the patient through the inhalation tube, Y-piece, and ET tube. If you want just oxygen to the patient quickly, we push oxygen flush valve and the low-pressure hose takes the oxygen from the cylinder, through the pressure reducing valve, into the inhalation valve bypassing the vaporizer. Next, I will examine how to make all the parts of the machine function properly, and discuss how to do a pressure check. First, I need to connect the breathing circuit components. I will attach the Y-tube, attached to the inspiratory and expiratory tubes, to the two matching valves. Then, I will attach the rebreathing bag. After this, I will make sure the scavenger system is in place. Once I have done this, I will make sure the oxygen supply is attached and I will turn it on. Then I will verify that I have at least half a tank of anesthetic and close the pop-off. I will then occlude the Y-piece with my thumb so no air can escape. Then I will push the oxygen flush valve until the manometer reads 20 cmH₂O. Then make sure it stays at this point. After this is verified, I will open the pop-off valve and unocclude. If it does not stay at the reading notify an advisor. Now I will discuss the care and maintenance of the anesthesia machine, since I have discussed the components and flow of gas.
Keeping the machine clean and dry is key to proper maintenance. You must change the Humid-vents monthly, they are placed between the ET tubes and the breathing tubes to removes the excess water. They help to keep the exhalation tube dry. Viral filters can be placed between exhalation valve and the exhalation tubes. This filter helps prevent the entrance of viruses into the machine and can be changed every two to three months. The gas cylinders should be inspected by the manufacture that we buy them from. As well as the pressure reducing valve and vaporizer should be inspected by them. Pressure gauges, manometers, flow meters, and flush valves should be checked for accuracy and proper
functioning. If there are ever leaks, we should replace the components that have caused the leaks. Valves can be inspected and cleaned as often as needed, the reservoir bag, breathing tubes, Y-piece, and any other piece should be cleaned after every use. These pieces should be disinfected, rinsed, rinsed and hung up to dry. As long as they are all still working well, these pieces can be reattached and reused. Knowing the functions of every part of the anesthesia machine is very important. Recognizing the pathway of gas from the cylinder to the patient is a key component of anesthesia. Finally, knowing how to pressure check the anesthesia machine is an invaluable skill for you to have.