Rebreathing Circuits and Accessories – SWT Circuits
Darvall Non-Heated Breathing Circuits
Darvall Smooth Wall Tubing (SWT) Circuits use low resistance, low volume, small diameter tubes. This new concept in circuit design offers HUGE efficiency advantages for the patient as well as for your practice.
Features & Benefits:
- Easy to use
- Fits all standard anesthetic gas machines
- Smooth Wall Tubing (SWT) Circuits reduce circuit resistance
- Reduced resistance means they can be used for smaller patients
- Smaller diameter tubing reduces circuit volume by up to 75%
- Reduced circuit volume improves response and efficiency
- SWT Circuits are kink-resistant
- MRI Compatible
- Easy to clean and dries thoroughly and quickly
- Two sizes: Small (12 mm) for animals up to 45#, and Large (16 mm) for animals over 45#
Pricing Information – Small Non-Heated – Product #8349
Pricing Information – Large Non-Heated – Product #8350
Smooth Wall Breathing Circuits
Less Resistance – More Efficient
Fits all standard anesthetic gas machines
They dry quickly and completely!
Heated and Non-Heated
Darvall’s MDS Y piece (Min. Dead Space 3.4ml) supplied with 12mm (1/2″) SWT circuits for animals 2 to 30kg (4-65lb)
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Darvall Heated Breathing Circuits
Features & Benefits:
- Simple to use
- Light-weight / portable
- Fits all standard gas machines
- Temperature of gases measured at Y-piece & displayed
- Temperature of patient measured & displayed
- Closed-loop feedback provides automatic shut-off for safety
- Hypothermia risk reduced, particularly in smaller animals
- Computer controlled precision
Is surface warming the best solution? This guide describes an innovative new paradigm for preventing heat loss during anesthesia.
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Heated Breathing Circuits
– Warms From Within
– Fits all standard anesthetic gas machines
– Now patient warming is as simple as
using a better breathing circuit
The first temperature-controlled breathing circuit of its kind. This new heated breathing circuit was developed by veterinarians to prevent the problems of hypothermia in anesthetized veterinary patients. Our breathing circuits can be used for all veterinary rebreathing anesthesia, with particular advantage for small animals. Now patient warming is as simple as using a better breathing circuit.
Pictured here: Darvall SWT Heated Circuit (#8347), Heat Controller (#8516) and KAB® CO2 Canister (#5265)
The complete Darvall SWT Heated Circuit Starter Set (#8531), includes:
- Heat Controller / Power Supply (#8516)
- Large (16mm) Darvall SWT Heated Circuit (#8348) for animals over 45#
- Small (12mm) Darvall SWT Heated Circuit (#8347) for animals up to 45#
- FREE SHIPPING within the contiguous US
Pricing Information – Starter Set #8531
We are so confident our SWT Heated Breathing Circuit is a game changer for patient warming that we offer a money back guarantee. If you are not satisfied with the Heated Breathing Circuit Set you have up to 30 days from receipt of product to contact Customer Service (866) 931-3292 for a return authorization. You will need to return the entire SWT Heated Breathing Circuit Set in its original packaging to DarvallVet prior to a refund being issued for your product purchase.
"I bought the Darvall [Heated Breathing Circuit] unit from you last year, and we use it on every anesthetic procedure. It has helped prevent hypothermia in all our patients. They recover quicker and with less complications. It also saves time because we would have to warm them up after a long dental procedure."

Dr. Eric Pearson
Home Pet Service - Kailua, HI
Darvall Breathing Circuits Accessories
Heated Lack NRB Circuit
for animals 0-15kg (0-35lb)
A heated Non-Rebreathing circuit to effectively warm small animals from the first breath.
Uses Low 100ml/min FG Flow
Just add Lack fitting with 12mm (1/2″) Heated SWT.
- Simple Lack adapter
- Safety APL valve with 20cm H2O relief
- Darvall’s MDS Y connector – only 3.4ml dead space
- 0.5L breathing bag
- Low Fresh Gas flow 100ml/kg/min
- Environmentally Sustainable NRB system
- Effective warming of the smallest animals
Can’t find what you need? We can help!
Please email us at gcs@darvallvet.com