How A Bain Circuit Works In Anaesthesia Delivery System?

There are a number of medical conditions or emergencies in which patients either face a problem in breathing or need some support for the same. That’s why, clinics and hospitals always have anaesthesia and ventilator circuits ready so that prompt service can be provided in case required. They have in place artificial breathing systems or can create breathing environments so that patients can get the help on an immediate basis.

So, you can expect a wide range of artificial breathing systems or set-ups at hospitals and bain circuit is one of them. These systems exist to help in connecting patient’s airway to a machine such that the atmosphere for artificial breathing is created. The system has a fresh gas entry pot, gas reservoir and corrugate tubes. All these help in ensuring proper breathing to patients.

Furthermore, the bain circuit available at hospitals is a co-axial modification of the basic T-piece system to ensure proper scavenging of the waste gases. It helps to let patients inspire fresh gas from the reservoir tube and then expire into the same tube. This circuit is very helpful as apart from scavenging of waste gases, it also offers low resistance to breathing.

Functions and advantages

The circuit helps in scavenging of waste anaesthetic gases and serves this purpose with ease. Its functionality is easy and patient-friendly and you can expect other advantages along the way.

Here are some of its functions and advantages –

  • It works in the same way a T-piece does
  • Unlike the T-piece, the tube that takes fresh gas to the patient is inside the reservoir tube
  • It’s the outer reservoir circuit that lets patients inspire fresh gas
  • The expiration from patients takes place into the reservoir tube
  • Expired gases are forced out of the reservoir tube and fresh gas comes in for the next inspiration
  • Exhaled gas is eliminated efficiently
  • Very helpful in scavenging and alternating positive pressure ventilation
  • A very sound way of scavenging of waste gases
  • Low dead space and low resistance to breathing
  • Efficient and inexpensive


We know how the bain circuit is an essential system at most hospitals for helping in creation of an artificial breathing environment. Its utility is huge in the scavenging of waste anaesthetic gases and its functionality is easy and patient-friendly.

Let’s look at some of features of the Bain –

  • A convenient anaesthesia delivery system available at most clinics and hospitals
  • One of most important systems to help in creation of an artificial breathing atmosphere
  • Cost-effective and lightweight in nature
  • It’s a modification of Mapleson D system and designed to facilitate scavenging of waste gases
  • It offers more clinical utility than the T-system, due to the modification
  • Fit for all surgical procedures
  • Adaptable to all ages
  • Comes with a single tube for convenience and is extremely simple to use
  • Come with a corrugated tube, expiratory valve and antistatic bag
  • Very compact and inexpensive
  • Equally beneficial to adults and children, or for people irrespective of age groups