Anaesthesia workstation

Vapourizer 

An anaesthetic vaporizer is a device generally attached to an anaesthetic machine which delivers a given concentration of a volatile anaesthetic agent. It works by controlling the vaporisation of anaesthetic agents from liquid, and then accurately controlling the concentration in which these are added to the fresh gas flow.

A Parenteral Drug (LVP, SVP) is defined as one intended for injection through the skin or other external boundary tissue, rather than through the alimentary canal, so that active substances they contain are administered, using gravity or force, directly into a blood vessel, organ, tissue, or lesion. They are infused when administered intravenously (IV), or injected when administered intramuscularly (IM), or subcutaneously into the human body. A large volume parenteral (LVP) is a unit dose container of greater than 100ml that is terminally sterilized by heat. Small volume parenteral (SVP) is a "catch-all" for all non-LVP parenterals products except biologicals.

Vapourizer Agent colour coding

Fluranes are color-coded – sevoflurane is marked yellow, isoflurane purple, enflurane orange and desflurane blue. Note the valve cap on the desflurane bottle – at 23.5 °C the boiling point of this compound is near room temperature.
Note:(including older agents such as diethyl ether orchloroform, although it would be dangerous to usedesflurane)

Anaesthesia Display or Monitor

Anaesthesia monitor display vital signs of patient ,vital signs, such as NIBP (non-invasive blood pressure), SPO2 (oxygen saturation in the arteries), and temperature. Higher end monitors can have added features that monitor EKG (electrocardiogram), IBP (invasive blood pressure), CO2 (carbon dioxide) .

Auxiliary Oxygen Flow Control

Auxiliary O2 flow control used to adjustment of O2 level flow to the patient.And alternate O2 control also provided.

General features of all anesthesia workstations

• enhance patient safety
  more reliable and capable basic components such as ventilators, vaporizers, flowmeters
  integrated, computer-controlled alarms
• feature advanced ventilation modes. Most are based on pressure controlled breaths, and allow the addition of PEEP (not all modes are available on every model).
  pressure control ventilation (PCV)
  pressure control ventilation with volume guarantee (PC-VG)
  synchronized intermittent mandatory ventilation (SIMV) with pressure- or volume-controlled breaths
  pressure support ventilation (PSV)
  continuous positive airway pressure (CPAP)
  bi-level positive airway pressure (BiPAP)
  airway pressure release ventilation (APRV)
• perform compliance and leak testing of the breathing circuit, and thereby produce unprecedented accuracy in delivered tidal volumes in volume-control mode (VCV), which may lessen the need for non-rebreathing circuits for children
• are smaller and lighter (in some cases) because they have integrated monitoring
• allow automated record keeping more easily than traditional designs
  electronic capture of fresh gas flow
  microprocessor integration
• feature improved monitors,and innovative new monitoring capabilities (spirometry, and flow-time waveforms)

Required components of an anesthesia workstation

The current anesthesia gas machine (workstation) standard isASTM F1850 (a standard promulgated by American Society for Testing and Materials). The European standard is EN740.

F1850 specifies what is needed for an anesthesia workstation. The components are typically built into new gas machines, or they may be added to older machines. Required components include:

• Battery backup for 30 minutes
• Alarms
  Grouped into high, medium, and low priority.
  High priority alarms may not be silenced for more than 2 minutes.
  Certain alarms and monitors must be automatically enabled and functioning prior to use, either through turning the machine on, or by following the pre-use checklist: breathing circuit pressure, oxygen concentration, exhaled volume or carbon dioxide (or both).
  A high-priority pressure alarm must sound if user-adjustable limits are exceeded, if continuing high pressure is sensed, or for negative pressure.
  Disconnect alarms may be based on low pressure, exhaled volume, or carbon dioxide.
• Required monitors
  Exhaled volume
  Inspired oxygen, with a high priority alarm within 30 seconds of oxygen falling below 18% (or a user-adjustable limit).
  Oxygen supply failure alarm
  A hypoxic guard system must protect against less than 21% inspired oxygen if nitrous oxide is in use.
  Anesthetic vapor concentration must be monitored.
  Pulse oximetry, blood pressure monitoring, and EKG are required
• Pressure in the breathing circuit is limited to 12.5 kPa (125 cm water).
• The electrical supply cord must be non-detachable or resistant to detachment.
• The machine must have at least one oxygen cylinderattached.
• The hanger yoke must be pin-indexed, have a clamping device that resists leaks, and contain a filter. It must have a check valve to prevent transfilling, and a cylinder pressure gauge. There must be cylinder pressure regulators. The machine must use pipeline gas as long as pipeline pressure is greater than 345 kPa (50 psi).
• Flowmeters:
  Single control for each gas
  Each flow control next to a flow indicator
  Uniquely shaped oxygen flow control knob
  Valve stops (or some other mechanism) are required such that excessive rotation will not damage the flowmeter.
  Oxygen flow indicator is to the right side of a flowmeter bank
  Oxygen enters the common manifiold downstream of other gases
  An auxiliary oxygen flowmeter is strongly recommended
• An oxygen flush is present, capable of 35-75 L/min flow which does not proceed through any vaporizers.
• Vaporizers
  Concentration-calibrated
  An interlock must be present
  Liquid level indicated, designed to prevent overfilling
  "Should" use keyed-filler devices
  No discharge of liquid anesthetic occurs from the vaporizer even at maximum fresh gas flow
• Only one common gas outlet at 22 mm outer diameter, 15 mm inner diameter, which is designed to prevent accidental disconnection
• Pipeline gas supply
  Pipeline pressure gauge
  Inlets for at least oxygen and nitrous oxide
  DISS protected
  In line filter
  Check valve
• Checklist must be provided (it may be electronic, or performed manually by the user)
• A digital data interface must be provided

Path of gases within the machine

Oxygen has five "tasks" in the AGM; it powers the

1. ventilator driving gas
2. flush valve
3. oxygen pressure failure alarm
4. oxygen pressure sensor shut-off valve ("fail-safe")
5. flowmeters.