How does anaesthetic machine work?
An anaesthetic machine, also known as an anaesthesia machine or a breathing system, is a medical device used to administer and control the flow of anaesthetic gases and oxygen to a patient during surgical procedures or other medical interventions that require anaesthesia. The primary function of an anaesthetic machine is to maintain the patient's breathing and provide a controlled delivery of anaesthetic agents to achieve the desired level of anaesthesia. Here's how an anaesthetic machine works:
1. Gas Supply: The anaesthetic machine is connected to a high-pressure gas source, typically medical-grade oxygen and compressed air. These gases are stored in cylinders or a central pipeline system.
2. Flowmeters: The machine has flowmeters that regulate the flow rate of oxygen and other gases. The flowmeters are calibrated to accurately measure and control the amount of gas being delivered to the patient.
3. Vaporizer: The anaesthetic machine includes a vaporizer, which is a device used to convert liquid anaesthetic agents into a gaseous form. The vaporizer is filled with a specific volatile anaesthetic agent, such as isoflurane or sevoflurane. The concentration of the anaesthetic vapour is controlled by adjusting the temperature and flow rate of the carrier gas (usually oxygen) passing through the vaporizer.
4. Gas Mixing: The anaesthetic gas, oxygen, and any other supplementary gases (such as nitrous oxide) are mixed together in the mixing chamber of the machine. This mixture of gases is then delivered to the patient.
5. Breathing Circuit: The anaesthetic machine is connected to the patient through a breathing circuit. The breathing circuit consists of various components, including tubing, a face mask, an endotracheal tube, or a laryngeal mask airway, depending on the type of anaesthesia being administered.
6. Ventilator: Many anaesthetic machines also incorporate a ventilator, which can assist or control the patient's breathing. The ventilator can deliver a predetermined volume and rate of the gas mixture to the patient, ensuring adequate ventilation during anaesthesia.
7. Monitoring Devices: The anaesthetic machine is equipped with various monitoring devices to ensure patient safety and track vital parameters. These devices may include:
- Anaesthetic gas monitors: Measure the concentration of anaesthetic agents in the gas mixture.
- Oxygen monitors: Measure the oxygen concentration in the gas mixture.
- Capnography: Monitors the carbon dioxide levels in the patient's exhaled gas.
- Pulse oximetry: Measures the oxygen saturation of the patient's blood.
- Blood pressure monitors: Measure the patient's blood pressure.
- Electrocardiogram (ECG): Monitors the patient's heart activity.
8. Alarm Systems: The anaesthetic machine has alarms and safety mechanisms to alert the healthcare professionals of any irregularities or deviations from the desired parameters. These alarms help ensure the safe administration of anaesthesia.
During the anaesthetic procedure, the anaesthesiologist or nurse anaesthetist closely monitors the patient's vital signs, adjusts the flow of gases and anaesthetic agents, and makes any necessary modifications to maintain the desired level of anaesthesia and ensure the patient's safety throughout the procedure.