Breathing systems and the anaesthetic machine Zsolt Molnár SZTE, AITI

Irish anaesthetist ( ) –Endotracheal tube, anaesthesia (The Magill endotracheal tube, oral & nasal designs) –An anaesthetic breathing system (Magill circuit and expiratory valve) –Intubating Forceps –Laryngoscope a straight bladed version –Catheter mount (endotracheal tube-to-circuit connector) –Endotracheal tube connectors, oral & nasal versions –Magill tracheal spray (glottis anaesthetic) –Single-lung anaesthesia –Endobronchial tubes and bronchial blockers –Bobbin flowmeters Sir Ivan Whiteside Magill

British anaesthetist Cardiff 1952 –Mapleson WW. The elimination of rebreathing in various semi-closed anaesthetic systems. Br J Anaesth 1954; 26: 323–32 –Mapleson WW, Mushin WW. Relaxant action in man: an experimental study. Anaesthesia 1955; 10: 265–78, 379–90 Mapleson WW. Br J Anaesth 2004; 93: WW Mapleson

„Auld” definitions Open-, semi open- Semi-closed, closed-systems „New”: Mapleson systems 1954 Rebreathing Non-rebreathing Introduction

V T 4-7 ml/kg V D 2-3 ml/kg Peak inspiratory flow (PIF) At rest: l/min Breathing cycle Inspiration – expiration – expiratory pause Physiolgy refreshment course

Parts FG inlet Rezervoire balloon Pop-off valve Efficacy FGF – to prevent CO 2 rebreathing Mapleson systems

Parts Disc Sharp edge Spring Safety opening P cmH 2 O Pressure relieving valve

„Magill attachment” >110 cm FGF = 1 x V A (70ml/kg/m) V A = ? PIF = ? Monitoring: capnograph Mapleson A – spont. breathing

A: normal B: rebreathing C: diaphragm movements D: cardiac oscillation E: sampling error F: bronchospasm Molnár ‘99 AB CD EF pCO 2 Capnography

History Birth of: intensive therapy, blood gas machine, and the use of Mapleson C 1952 Coppenhagen: polio-epidemic 31 patients – 21 dead within 72 hrs Bjorn Ibsen ( ) Waters: To-and-fro Lassen HCA Management of poliomyelitis. In HCA Lassen Management of life threatening poliomyelitis. Copenhagen, ; E.S. Livingstone Ltd, London

Water’s circuit Molnár ‘99 Mask, ET-tube O2O2 Valve Rezervoire baloon

E: Ayre’s T-piece Spont: FGF = 1.5 x V A IPPV: FGF = 3 x V A F: Jackson-Rees Monitoring PEEP Mapleson E and F

T-piece Molnár ‘99 T-piece Inlet Outlet

A happy chapy on T-piece Molnár ‘99

The anaesthetic machine Cylinders (O 2, N 2 O, Air) Rotameters Vaporizers Breathing circuit CO 2 absorber Safety: FiO 2 + alarm O 2 bypass Pressure relieving valve

Rebreathing system (circuit)

CO 2 absorber CaOH 2, NaOH, sylicate CO 2 + 2NaOH Na 2 CO 3 + H 2 O + heat Na 2 CO 3 + CaOH 2 2NaOH + CaCO 3

Rotameters

Gas specific Safety features: Min FiO 2 = 0.3 FiO 2 alarm

Vaporisers ages ago… Inside the circuit Small vaporizing surface Quick cooling

…and today Outside the circiut Well insulated containers

…and today Outside the circiut Well insulated containers Agent safe

…and today Outside the circiut Well insulated containers Agent safe Heat compensation

Mapleson systems: advantages Simple, cheap, safe Low resistance Good for practice Mapleson systems: disadvantages Non-economic Not environment friendly High heat and humid loss Summary Get to know your equipment!