Anesthesia Machine: Components, Types, and How to Choose
Technical guide for anesthesiologists and purchasing directors · Colombia 2026
Anesthesia machine: what it is, components, types, and how to choose one for your operating room in Colombia
From vaporizers to the rebreathing circuit — everything you need to know about the anesthesia workstation: its 5 functional blocks, the types available in Colombia, and the criteria for choosing the right equipment for your facility
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Technical-clinical team at GSMED Imaging
Content based on: RGT Consultores (Anesthesia Machines), ScienceDirect EMC (Anesthesia apparatus, 2013), Scribd — The Complete Anesthesia Machine, Bimedis (TOP anesthesia machines 2025), Medicox Colombia (Medtronic anesthesia circuit), Invermedica Colombia (Mindray ventilators), and data from Colombian distributors.
The anesthesia machine — technically called an "anesthesia workstation" — is the most complex piece of equipment in the operating room. It integrates mechanics, pneumatics, and electronics into a single device that must deliver medical gases with pinpoint precision, ventilate the patient, monitor their parameters, and remove residual gases from the surgical environment — all at the same time, without failure, for hours. This guide explains how it works, what is inside, and how to choose the right one for your facility.
1. What does an anesthesia machine do? — Its function in one sentence
The anesthesia machine receives medical gases (oxygen, nitrous oxide, medical air), precisely mixes the inhaled anesthetic agent (sevoflurane, desflurane, isoflurane), delivers the mixture to the patient through the breathing circuit, and manages the removal of exhaled gases using a scavenging system. Simultaneously, it monitors the patient's respiratory parameters and sounds alarms in the event of any deviation.
2. The 5 functional blocks of the anesthesia machine
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Block 1 — Gas supply
Connection to the hospital gas network + backup cylinders. Pressure regulators, shut-off valves, and low-pressure alarm systems.
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Block 2 — Flowmeters
Rotameters or electronic flowmeters that measure and control the flow of each gas (L/min). They allow precise adjustment of the O₂/air/N₂O mixture.
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Block 3 — Vaporizers
They convert the volatile liquid anesthetic agent into vapor and mix it with the fresh gas flow at the exact programmed concentration (%). They are agent-specific — sevoflurane, desflurane, isoflurane.
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Block 4 — Patient circuit + ventilator
Inspiratory/expiratory tubing, reservoir bag, one-way valves, CO₂ absorber (soda lime), and an integrated ventilator for mechanical ventilation during anesthesia.
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Block 5 — Monitoring
Integrated monitor for anesthetic gases, capnography, pulse oximetry, blood pressure, ECG, and temperature. Main screen with configurable alarms.
The CO₂ absorber — the most overlooked component The CO₂ absorber (filled with soda lime or similar) is the most critical consumable component of the breathing circuit. Its function is to absorb exhaled CO₂ before the gas returns to the patient in the rebreathing circuit. When the soda lime is exhausted, CO₂ is reinhaled — silent hypercapnia. The exhaustion indicators (color change) must be checked at the start of each procedure. The replacement frequency depends on the fresh gas flow and the duration of the surgery.
3. Types of anesthesia circuits: open, semi-open, semi-closed, and closed
| Circuit type | Rebreathing | Fresh gas flow | Typical use |
|---|---|---|---|
| Open circuit | No rebreathing | Very high (4–8 L/min) | Neonatal pediatric — Mapleson-type systems |
| Semi-open | Minimal | High (2–4 L/min) | Short procedures · Pediatrics |
| Semi-closed (the most commonly used) | Partial — with CO₂ absorber | Low-to-moderate (1–2 L/min) | The standard in most Colombian operating rooms |
| Closed circuit | Total — with CO₂ absorber | Very low (≤0.5 L/min) | Low-flow anesthesia — maximum agent efficiency |
4. Inhaled anesthetic agents: which vaporizer you need
| Agent | Physical state | Boiling point | Clinical use in Colombia | Special vaporizer |
|---|---|---|---|---|
| Sevoflurane | Volatile liquid | 58.5°C | The most commonly used in Colombia — induction and maintenance | Standard sevoflurane vaporizer |
| Isoflurane | Volatile liquid | 48.5°C | Maintenance — lower cost, less pleasant for induction | Standard isoflurane vaporizer |
| Desflurane | Volatile liquid | 23.5°C (almost room temperature) | High complexity — faster recovery | Special heated vaporizer (TEC 6) — the most expensive equipment |
| Nitrous oxide (N₂O) | Gas (cylinders) | -88.5°C | Complementary analgesia, inhalational induction | No vaporizer — direct flowmeter |
5. Brands available in Colombia and selection criteria
| Brand · Model | Positioning | Ideal for |
|---|---|---|
| Mindray WATO EX-20/35/55 | Competitive price · Intuitive interface · Growing in Colombia. WATO EX-55 with advanced ventilation and multiple modes. | Medium-complexity clinics · Initial anesthesia investment · Controlled budget |
| Mindray A7 | High-end Mindray · Low-flow anesthesia system · AI safety backup | Complex surgeries · Low-flow anesthesia · High complexity |
| Dräger Fabius GS / Primus | German benchmark of high reliability · Wide availability of spare parts · High cost | University hospitals · Cardiovascular surgery · Highest-demand environments |
| GE Aisys CS² / Avance | GE platform with full integration of the GE ecosystem (monitoring, ventilation). Advanced software. | Hospitals with a GE ecosystem · High complexity · Transplant surgery |
| Mindray / Refurbished equipment | Lower entry cost · Older-generation Dräger, GE, or Datex equipment in good condition | First operating room · Low-complexity procedures · Very tight budget |
6. Frequently asked questions
How much does an anesthesia machine cost in Colombia in 2026?
The range is wide depending on the machine's level. A basic anesthesia machine (Mindray WATO EX-20 or equivalent refurbished model) can be purchased for between $45,000,000 and $90,000,000 COP. A mid-range machine (Mindray WATO EX-55, refurbished Dräger Fabius GS) ranges from $90,000,000 to $200,000,000 COP. A new high-end machine (Dräger Primus, GE Aisys CS², Mindray A7) can exceed $200,000,000 to $400,000,000 COP. Added to this are the costs of the vaporizers (included or separate), the scavenging system (residual gas removal), and the installation of the medical gas network.
Can the anesthesia machine be used as an ICU ventilator?
Technically, yes — during the COVID-19 pandemic, the FDA temporarily approved the use of anesthesia machines as ICU ventilators when there was a shortage of conventional ventilators. However, the FDA itself recommended that as soon as possible, the anesthesia machine should return to its original function, and that anesthesiologists must be present at all times during its use as an ICU ventilator. Anesthesia machines are not designed for continuous 24-hour use — their circuit and alarm systems are not equivalent to a dedicated ICU ventilator. In Colombia, this practice is not recommended as a permanent solution.
How often should the anesthesia machine be serviced?
Colombian and international standards establish: daily safety verification before each surgical shift (mandatory checklist that the anesthesiologist must document); semiannual or annual preventive maintenance by a manufacturer-certified technician (flowmeter calibration, vaporizer verification, circuit inspection, leak test); and soda lime inspection at each procedure or batch of procedures. Failure to perform maintenance is a cause of serious adverse events — circuit patency and vaporizer accuracy are critical patient safety points.
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