Evaluation Background: Anesthesia Units for General-Purpose and Low-Acuity/Ambulatory Surgery Applications

Here's background for our Evaluations of anesthesia units that can be used for both general-purpose and low-acuity/ambulatory surgery applications, providing a summary of our product ratings, as well as a rundown of the key aspects of the technology that are critical to making wise purchasing decisions. Learn how the technology is used, which specs are important and why, what factors we test for, hospitals' interest in each vendor, costs of ownership, and more.

Anesthesia units are devices that continuously or intermittently administer a mixture of gases, varying the proportion of gases in order to control the patient's level of consciousness. The gases in the mixture are oxygen, air or nitrous oxide, and an anesthetic vapor. These devices are also designed to facilitate spontaneous, controlled, or assisted ventilation while using these gas mixtures.

Anesthesia units are a relatively mature technology. Manufacturers are introducing new features, but these generally do not affect the basic performance of the devices. Newer systems are more likely to have ventilation modes and ventilator performance specifications (e.g., maximum peak flow) in line with modern ICU ventilators.

Anesthesia units are composed of two basic subsystems:

1. A gas delivery platform, which creates and delivers gas mixtures and monitors the patient's respiration (e.g., rate, airway pressure)

2. A data analysis and distribution system

A physiologic monitor is often physically mounted on an anesthesia unit for convenience, and while it is possible in some instances to integrate the two devices so that some information passes back and forth, they are typically not connected in this way.

Anesthesia units are used for general anesthesia during surgery for the entire range of patients (neonates through adults). Anesthesia units can also be used during monitored anesthesia care (MAC). In MAC, anesthesia is provided intravenously but a gas anesthesia unit is present to provide supplemental oxygen (typically via a nasal cannula) and capnography as well as in the event that additional respiratory support becomes necessary.

Anesthesia units used for general-purpose applications can be used with the full range of patients. Some units have ventilation modes and performance comparable to modern intensive care ventilators. This allows the anesthetist to provide better care during surgery for patients who require mechanical ventilation outside of surgery because of their diseased or injured lungs.

Anesthesia units used in low-acuity/ambulatory surgery settings can be used with pediatric and adult patients. Since difficult-to-ventilate patients are not typically treated in these settings, the advanced ventilation modes, performance, and features that are primarily useful when treating such patients are less likely to be needed. A small footprint is advantageous in the ambulatory...