## What is the difference between rebreathing and non-rebreathing systems?

Rebreathing circuits use a carbon dioxide absorber to trap and remove CO2 so the patient can breathe gases that have been recycled through the machine. Non-rebreathing circuits use high gas flows to washout expired CO2 from the circuit before the patient takes its next breath.

How do you calculate the size rebreathing bag required?

Rebreathing bags generally come in 500mL, 1L, 2L 3L, & 5L for small animal anaesthesia. There is an easy formula to work out which size you need! Times the patient’s bodyweight by 10 (tidal volume in mLs) then times by 6. Divide this by 1000 and you have the size you need in litres.

What is a semi closed rebreathing system?

Semi-closed—A semi-closed system has a reservoir such as a breathing bag and allows for partial rebreathing. For example, a Mapleson circuit or a circle at low FGF (< VE), the most commonly used method today.

### What size of animals do we use non rebreathing systems for?

Non-Rebreathing circuits are designed to deliver oxygen and anesthetic gases with less resistance to breathing in small patients under 10 lbs (7 kg).

What is a rebreathing system?

In rebreathing or “circle” systems, all or part of the gases exhaled by the anaesthetized patient are returned to the system to be recycled. Rebreathing systems must contain a canister of a chemical absorbent (Diagram 1 – #10) to permit removal of all the carbon dioxide (CO2) exhaled by the patient.

How do you measure a dog’s ET tube?

The length of tube required can be estimated by measuring it against the dog. The tip should lie at the point of the shoulder and the connector at the incisor arcade. In a live animal, you would now check that the depth of anaesthesia is appropriate by assessing jaw tone.

#### How do you check a dog’s ET tube?

Measuring length

1. Place the patient into lateral recumbency.
2. Using an ET tube, measure the correct insertion length by placing it against the point of the scapula (top of the shoulder) as this is approximately just above the bronchial bifurcation, following the airway, and measure against the canine teeth.

What is the purpose of a rebreathing system on an anesthesia machine?

Anesthesia machines, paired with breathing circuits (nonrebreathing circuit [NRC] or rebreathing circuit [RC]), are designed to deliver oxygen (O2) and inhalant anesthetic to the patient and to prevent rebreathing of carbon dioxide (CO2) by the patient.

How do you intubate a dog?

Ask your assistant to gently squeeze the reservoir bag as you slowly press the syringe plunger. With your face close to the dog’s mouth, continue to inflate the cuff until no breath is heard escaping around the ET tube. The dog should now only be breathing through the tube. Be careful not to overinflate the cuff.

## What is a rebreathing bag?

The reservoir bag was, in the past, called a rebreathing bag. Years ago it was possible for the patient to exhale into the nasal hood, and if the total flow of gas from the sedation unit was low, the exhaled gases could be forced backward through the conducting tubing to reach the reservoir bag.

What is a non rebreathing machine?

Anesthesia machines, paired with breathing circuits (nonrebreathing circuit [NRC] or rebreathing circuit [RC]), are designed to deliver oxygen (O 2) and inhalant anesthetic to the patient and to prevent rebreathing of carbon dioxide (CO 2) by the patient.

What are the disadvantages of rebreathing with a 3L bag?

(Volume of rebreathing circuit with a 3L bag is approxi-mately 6L. Volume acts as a “buffer” to changes in anesthetic concentration.) High flow of dry cool gas is administered to the patient, which can cause significant heat and humidity loss. This can contribute to hypothermia, especially in small patients.

### What are the advantages of re-breathing systems?

Economy of gas flows required and concerns over environmental and operating room pollution: re-breathing systems work efficiently at considerably lower gas flows than non-rebreathing systems. In the spontaneously breathing patient the (Mini) Lack and Magill require less fresh gas than the T-piece or Bain.

What is the correct fresh flow for rebreathing?

As stated above, it is essential that the correct fresh flow is used to prevent rebreathing of gas rich in CO 2. The gas flow is based on a multiple of the patient’s minute volume (weight x tidal volume x respiratory rate). Thus, if the patient’s respiratory rate increases, the fresh gas flow should be increased (Table 2).