AMIR SALAH MODERN ANAESTHETIC MACHINE MODERN ANAESTHETIC MACHINE 1 of 4

ALTERNATIVES terminology -Anaesthetic workstation. -Anaesthetic delivery system. It may be : simple simple pneumatic pneumatic computerized computerized

COMPONENTS 1.Anaesthetic machine. 1.Anaesthetic machine. 2.Vaporizers. 2.Vaporizers. 3.Ventilator 3.Ventilator 4.Scavenging system. 4.Scavenging system. 5.Monitors. 5.Monitors. 6.Breathing circuits (Anaesthetic circuits). 6.Breathing circuits (Anaesthetic circuits).

Anesthetic Machine GAS SUPLLY OXYGEN NITROUS OXIDE AIR

Gas Supply Method 1.Cylinders: 1.Cylinders: O 2 : 2000 psi =133 bar (kgf/cm 2 ) O 2 : 2000 psi =133 bar (kgf/cm 2 ) =133x100 K pascal =133x100 K pascal N 2 O :750 psi =51 bar(kgf/cm 2 ) N 2 O :750 psi =51 bar(kgf/cm 2 ) =51x100 K pascal =51x100 K pascal 2.Piping system : 2.Piping system : O 2 :45-50 psi = 3 x 100 K pascal O 2 :45-50 psi = 3 x 100 K pascal N 2 o:45-50 psi = 3 x 100 K pascal N 2 o:45-50 psi = 3 x 100 K pascal The pressure is reduced by high press flow control regulator valve from 2000 to 45 psi ; then another low press valve located down stream reduces press from 45 to 14.7 psi (1 bar ). second stage O 2 regulator valve not only reduces but also regulates a constant press to O 2 flow regardless of fluctuation of O 2 pipeline press

Additive valves 1.Fail-safe valve Shuts off or reduced N 2 o if O 2 is reduced: Mechanically Mechanically Pneumatically Pneumatically 2.Machine outlet valve between vaporizers and common gas outlet to prevent back flow into vaporizer 3.Flow control valve : Operator ; rotameter

4.O 2 Flush valve: It allows direct communication bet. O 2 high press. And the low press. Circuits down stream of vaporizer and machine outlet valve.O 2 delivery is of 35 to75 L/min with press. 50, 7 or 18 psi according to machine style. It allows direct communication bet. O 2 high press. And the low press. Circuits down stream of vaporizer and machine outlet valve.O 2 delivery is of 35 to75 L/min with press. 50, 7 or 18 psi according to machine style. Hazards of OFV : Hazards of OFV : 1. Can stick in fully open  barotrauma 1. Can stick in fully open  barotrauma 2.Stick in partial opening  awareness 2.Stick in partial opening  awareness 3.Intra operative  dilute anaesth. 3.Intra operative  dilute anaesth. 4.Inspiratory phase  barotrauma 4.Inspiratory phase  barotrauma 5.Excess volume cannot be vented. 5.Excess volume cannot be vented. 6.Free standing vaporizer  high anaesth conc. 6.Free standing vaporizer  high anaesth conc. 7.Preoperative use for checking leak in machine can close the check valve at the common outlet and major leak can go undetected. 7.Preoperative use for checking leak in machine can close the check valve at the common outlet and major leak can go undetected.

BREATHING SYSTEMS BREATHING CIRCIUTS ANAESTHETIC CIRCUITS

DEFINITION A breathing system connects the O 2- containing FGF supply (anaesth machine) to the piece of equipment that delivers to the patient’s URT : A breathing system connects the O 2- containing FGF supply (anaesth machine) to the piece of equipment that delivers to the patient’s URT : ETT, facemask, LAM, injector (although it does not have to carry anaesth gases or vapors. ETT, facemask, LAM, injector (although it does not have to carry anaesth gases or vapors.

FUNCTIONS of BS 1.Maintain the delivery of O 2. 1.Maintain the delivery of O 2. 2.Remove CO 2 from alveolar gas. 2.Remove CO 2 from alveolar gas. As oxygenation is not a problem with supplementation of O 2, rebreathing (inefficent removal of CO2) is the main function to evaluate, compare, classify and study BS. As oxygenation is not a problem with supplementation of O 2, rebreathing (inefficent removal of CO2) is the main function to evaluate, compare, classify and study BS.