## What is considered low flow anesthesia?

## What is considered low flow anesthesia?

Low flow anesthesia uses a fresh gas flow of less than half the minute ventilation of the patient, which is most often less than 3.0 L/min on average in a normal adult.

### How is low flow anesthesia calculated?

min−1) for patients administered low-flow anaesthesia using the formula: (inspired O2 fraction−end-tidal O2 fraction) × minute ventilation 1, but we suggest that the alveolar minute ventilation, not the total minute ventilation, should be used for this calculation.

#### What does a low flow technique mean?

Low-flow anaesthesia is defined to be an inhalation anaesthetic technique in which the rebreathing fraction at least amounts to 50%, where at least 50% of the exhaled gas mixture is returned to the patient after CO2 removal in the next inspiration.

**How do you calculate anaesthesia flow rate?**

- First estimate the TIDAL VOLUME which is 10-15mls/kg 10 x 20 = 200mls.
- Next calculate the MINUTE VOLUME (tidal volume x respiratory rate) 200 x 10 = 2000mls or 2L.
- Finally multiply the minute volume by the CIRCUIT FACTOR 2 x 1.5 = 3L.

**What is a closed low flow circle system?**

When the adjustable pressure limiting (APL) valve is closed and all the exhaled gases without carbon dioxide are returned to the patient, the system becomes a totally closed one. Such a circle system can be used with flows as low as 250 to 500 mL and clinically can be termed as low-flow systems.

## What is fresh gas flow rate?

The fresh gas flow rate is the total volume of gas that flows from the anesthetic machine into the breathing system per minute. This includes oxygen, nitrous oxide and any other gases that may be employed.

### How is FIO2 anesthesia calculated?

To calculate the percentage of oxygen, take the total amount of oxygen (which is going to be 100% of the third liter or 1000ml, and 21% of each of the liters of air, or 210 ml each, for a total of 1420) and divide it by the total gas flow (3000ml). So 1420/3000 is 0.47, or 47% FIO2.

#### Where is the desired concentration of anesthetic gas set in a rebreathing system?

For adults, the desired expiratory isoflurane concentration is 1.2%, for sevoflurane 2.2% and for desflurane 5%.

**How do you calculate FiO2 from flow rate?**

FiO2 = 20% + (4 x oxygen liter flow) Breathe Rate – how slow or fast the person is breathing.

**What happens if APL valve is closed?**

## What are three different types of anesthesia circuits?

3 types of anesthesia

- General anesthesia: Patient is unconscious and feels nothing. Patient receives medicine by breathing it or through an IV.
- Local anesthesia: Patient is wide awake during surgery. Medicine is injected to numb a small area.
- Regional anesthesia: Patient is awake, and parts of the body are asleep.