PART 3: Breathing System Parts A&A pgs 116-131 PART 3: Breathing System Parts The system that brings the fresh gas from the vaporizer to the patient AND takes the expired gases from the away from the patient. Parts: unidirectional valves, pop off valve, CO2 canister, negative pressure relief valve, pressure manometer. Starts with the fresh gas inlet

Unidirectional Valves One-way valves that allow the flow of fresh gas to only travel in one direction. Valve is either a rigid disk or a flap that flutters as gas flows past it. 1. ____________ unidirectional valve: opens as the patient inhales 2. ____________ unidirectional valve: opens as the patient exhales Prevents the exhaled gases from traveling back towards the patient.

Unidirectional Valves *These valves can be used to monitor respiratory rate of the patient

Large animal system

Carbon Dioxide Canister Exhaled gases flow past the expiratory unidirectional valve and into the CO2 canister CO2 canisters usually contain _________ __________ granules that selectively absorb CO2 from other gases breathed out by the patient Examples: Soda Lime; CarbOLime

Carbon Dioxide Canister If CO2 absorption is occurring: The canister should feel warm and have moisture in it Capnometer measurements should be WNL The inspiratory carbon dioxide should read 0 mm Hg Recommended to change out granules q 6-10 hours of use VTI note: change _____________ of use PPE is required

Carbon Dioxide Canister Granules may become ___________ before ten hours! 1. Color change to violet or pink (depending on the brand). *Most brands change _________________. Replace granules mid-anesthesia if you have ___________ color change. Once color changes, it is possible to change back to white-ish within hours! 2. CO2 saturated granules are hard and brittle New ones can be chipped and crumbled with your fingers

Using fully exhausted granules can lead to hypercapnia in the patient Using fully exhausted granules can lead to hypercapnia in the patient. Note: can also cause carbon monoxide poisoning when using isoflurane.

Pressure Manometer Unit is: ____________ Measures pressure of gas within the breathing system This includes the patient’s lungs! Unit is: ____________ Should read between ________________ during normal respirations When patient is connected, gauge should never exceed: 20 cm H20 in dogs and 15 cm H20 in cats

Pop-off Valve - aka pressure relief valve, exhaust valve Allows exhaled gas to leave the breathing system This allows for a steady pressure within the system since new gas is always being added in Always kept open Prevents the build-up of excess gas or pressure within the circuit. If pressure were allowed to build up (left the pop-off valve closed), the alveoli in the lungs could rupture!

Occlusion Valve These are safety regulated

Negative Pressure Release Valve aka Air Intake Valve Special feature activated in emergencies Indicated by no gas flow or completely empty reservoir bag If _____________ pressure is detected in the circuit, this valve opens and allows room air in When would this happen? 1. Instances when there is excessive __________ Ex: When an active scavenging system is utilized 2. O2 flow rate is too low or tank runs out of O2 ALWAYS keep an eye on your tank pressure gauge

Part 4: Scavenging System SAFTEY A&A Pg. 356 To reduce exposure to WAG Three major types of scavenging systems: 1. Active Scavenging System Connected to a vacuum that sucks the waste gases out of the machine…concerns? Runs through a drop down line, through pipes in the ceiling, and outside –must be turned on! Expensive, maintenance required

Scavenging System: Active

Scavenging System 2. Passive Scavenging System Uses pressure in circuit to expel gases from the machine, out through a hole in the wall Must be room adjacent to the outside

Scavenging System 3. Absorption Devices Canister that contains ___________ ____________ Cheaper than installing a scavenger Portable Easy to use with little maintenance Example: F/air canister

F/air Canister Must be discarded after 12 hours of use OR a gain of ___________ in weight Must weigh and label F/air canister before use! Never occlude the bottom Filter on the bottom must always have air flow Down side?: do not absorb _______ ________