GE Aestiva 5 Service Manual

							7 Theory of Operation and Specifications 
1006-0939-0007-77-7
Breathing system
schematic
AB.23.106 
						

							Aestiva
7-81006-0939-000
7-8
Electrical block diagram
O2 Sensor Flow Sensors Bag/Vent Switch Canister Release Breathing Circuit Module
Absorber Control Panel CO
2 Bypass RS232C
System switch
O2 supply fail and   flush switches
AB.90.089
Tec 6 Outlet 100-120 Vac
220-240 Vac
50/60 Hz
Task Light
Connector Board
Connector Board
Front PanelPneumatic
EngineSensor Interface
Board MicroController
Board BatteryTwo Stage
FilterToroid
AC Inlet Module
- Fuses
- Voltage Selector
Assembly 
						

							7 Theory of Operation and Specifications 
1006-0939-0007-97-9
Pneumatic circuits
Gas supplies
(items 1-6)Refer to Figure 7-8 for location of items. Gas goes into the system through a 
pipeline or cylinder connection. All connections have indexed fittings, filters, 
and check (one way) valves. Gauges show the cylinder and pipeline pressures. 
A regulator decreases the cylinder pressures to the appropriate system 
pressure. A pressure relief valve helps protect the system from high pressures.
To help prevent problems with the gas supplies, install yoke plugs on all empty 
cylinder connections.
ww w wWARNINGDo not leave gas cylinder valves open if the pipeline supply is in 
use. Cylinder supplies could be depleted, leaving an insufficient 
reserve supply in case of pipeline failure. 
O
2 flow (items7-14, 27)Pipeline or regulated cylinder pressure supplies O2 directly to the pneumatic 
outlet and the ventilator (O
2 ventilators). A second regulator decreases the 
pressure for the flush valve and the auxiliary flowmeter. 
The flush valve supplies high flows of O
2 to the fresh gas outlet when you push 
the flush button. The flush switch uses pressure changes to monitor the 
position of the flush valve. A message on the ventilator tells you when Flush is 
ON.
When the system switch is ON, O
2 flows to the rest of the system and there is a 
minimum flow of 25 to 75 mL/min through the O
2 flowmeter.
A secondary regulator supplies a constant O
2 pressure to the flow meter.
An electrical switch monitors the O
2 supply pressure. If the pressure is too low, 
an alarm appears on the ventilator. 
Air, N2O, and
third gas flow
(items 7, 8, and 15-23)Balance regulators control the flow of N2O and the optional gas (CO2, Heliox) to 
the flow control valves. Oxygen pressure at a control port adjusts the output of 
the regulator. This stops flow during an O
2 supply failure and makes sure that 
the hypoxic gas pressures increase and decrease with the O
2 supply pressure.
A chain linkage on the N
2O and O2 flow controls helps keep the O2 
concentration higher than 20% (approximate value) at the fresh gas outlet. 
Pipeline or regulated cylinder pressure directly supply Air to the ventilator (Air 
Ventilators). When the system switch is ON, air flows to the rest of the system. 
A secondary regulator supplies the air flow control valve. Because there is no 
balance regulator, air flow continues at the set rate during an O
2 supply failure. 
						

							Aestiva
7-101006-0939-000
7-10
Mixed gas (item 26)The mixed gas goes from the flowmeter outlet through the vaporizer that is ON, 
to the fresh gas outlet, and into the breathing system. A pressure relief valve 
sets the maximum outlet pressure.
Key to Numbered
Components1. Pipeline pressure gauge
2. Pipeline connection
3. Cylinder pressure gauge
4. Cylinder connection
5. Cylinder pressure regulator
6. Pressure relief (opens at approx. 918 kPa)
7. Supply connections for the ventilator
8. System switch
9. Alarm for low O
2 supply pressure
10.Secondary O
2 regulator
11.O
2 flow control valve
12.O
2 flow tube
13.Flush regulator
14.O
2 Flush
a. Flush valve
b. Switch (used with the ventilator)
15.N2O balance regulator
16.N
2O flow control valve
17.N
2O flow tube
18.Air secondary regulator
19.Air flow control valve
20.Air flow tube
21.Optional gas balance regulator
22.Optional gas flow control valve
23.Optional gas flow tube
24.Vaporizer port valve
25.Vaporizer
26.Pressure relief (opens at approx. 38 kPa)
27.Auxiliary flowmeter (optional)
Key to Symbols
Pneumatic Connection
Direction of Flow
Check Valve (approx. 10 L/min reverse flow -STP) Filter 
						

							7 Theory of Operation and Specifications 
1006-0939-0007-117-11
Figure 7-7 • Pneumatic circuit
AA.96.131 
						

							Aestiva
7-121006-0939-000
7-12
Suction regulators (optional)
Venturi Suction
RegulatorSupply: Air or O2 from system gas supply
Drive gas consumption: 75 L/min
Maximum Vacuum: 457 mm Hg with pipeline drive gas at 345 kPa
Minimum flow: 20 L/min
Sound level 53 dBA
Accuracy: 5% of full scale
Continuous
Suction RegulatorSupply: External vacuum
Vacuum levels: 0-200 mm Hg and full line vacuum
Maximum flow: >20 L/min
Accuracy: 5% of full scale
O2 flowmeter (optional)
Supply: O2 from system gas supply
flow rates: 0-10 L/min
Accuracy: 5% of full scale 
						

							7 Theory of Operation and Specifications 
1006-0939-0007-137-13
Breathing system
There are two types of breathing circuit modules (Figure 7-8):
1. Circle
2. Mapleson D or Bain (With Mapleson D/Bain circuits one flow sensor measures 
Inspiratory and expiratory flows. The other measures fresh gas.)
Tabs on the circuit modules fit into infrared switches on the breathing system bulkhead. 
The ventilator uses these switches to identify the circuit module.  
Direct fresh gas
connections
(common and
auxiliary outlets)When you make a direct connection to one of these outlets:
•Mechanical ventilation is not available.
•The pressure gauge, Bag/Vent switch, APL valve, and bag arm are not part of the circuit. 
•Volume and pressure monitoring are not available.
•Flow from the auxiliary outlet to the O
2 sensor is: Module Patient Circuit 
ConnectionsOne-Way Valves
Circle Left: inspiratory
Right: expiratoryInspiratory and expiratory check 
valves
Mapleson D/ Bain Left: to-fro
Right: fresh gasNone
3 L
2L
1 L
1020
30 40
50 60 70 80
 cmH2O  Back pressure vs. flow to O
2 sensor 
						

							Aestiva
7-141006-0939-000
7-14
1.  O
2 sensor (ventilator) Or plug
2. Inspiratory port
3. Tabs (identify the breathing circuit module to ventilator)
4. Expiratory port
5. To-Fro port
6. Fresh gas port
7. Flow sensor module connector (used with ventilator)
8. Optical switches (use tabs to identify circuit module)
9. Internal connection (exhaled gas flows to absorber during expiration)
10. Internal connection (to Bag/Vent switch)
11. Auxiliary Common Gas Outlet (some models)
12. Selector switch (Auxiliary Common Gas Outlet)
13. Common Gas Outlet
14. Internal connection (mixed gas from absorber during inspiration)
15. Internal connection (Aux. Com. Gas Outlet to O
2 sensor)
16. Pressure gauge tap
17. Drain valve (push in to drain water into the drain dish at bottom of absorber)
Note: Items 11 and 13 are both called fresh gas outlets.
Figure 7-8 •  Breathing circuit modules and connections
1
Circle Module 
Mapleson D / Bain
7
8
9
10
11 12 13 14 15 16
234536
17
AB.23.210
AB.23.056 
						

							7 Theory of Operation and Specifications 
1006-0939-0007-157-15
Breathing system specifications
Volume 5500 mL
Absorbent 1.35 kg (400 mL) / canister
Connections    
Breathing circuit modules: Circle or Bain modules
Common gas outlet: ISO 5356 type connector (Standard 22 mm OD or 15 mm ID conical 
friction fit connectors). Remove the breathing circuit module to access.
Auxiliary outlet: ISO 5356 type connector on the front of the breathing system (Standard 
22 mm OD or 15 mm ID conical friction fit connectors) (Optional).
System leakage
These values are for continuous pressure and are higher than those expected during 
mechanical ventilation.
≤ 300 mL/min total at 3 kPa; ≤75 mL/min for all connectors and two part tubes and 
≤ 225 mL/min for all other breathing system assemblies. 
System compliance
Volume of gas lost due to internal compliance (bag mode only) 5.15 mL/cmH
2O.
Breathing system resistance
Y piece or T piece adds ≤0.15 kPa expiratory resistance at 1 L/sec.
10 20 30 40 50 60 0 0 1 2 3 4
5 6
flow rate L/min Pressure 
drop
cmH
2O
Breathing System Resistance
 
Inspiratory
Expiratory 
						

							Aestiva
7-161006-0939-000
7-16
Pressure required to open inspiratory and expiratory valves
Dry:          0.49 cmH
2O
Moist: 0.91 cmH
2O
Breathing system leakage (average during use)
APL Valve
Approximately 0 to 70 cmH
2O
Pressure Flow Data (APL Valve Completely Open)
System volume: 5500 mL 
Gas scavengingPassive scavenging:
Positive pressure relief: 10 cmH
2O
Negative pressure relief: 0.5 cmH
2O
Outlet connector: 30 mm male taper swivel
Active scavenging:
Particle filter at the outlet has a pore size of 225 microns. All flow data uses a new filter.
** * *
 Other market-specific connectors may be available.Pressure Bag Mode (ml/min) Vent Mode (ml/min)
30 cmH
2O0.089 0.063
60 cmH
2ON/A 0.106
90 cmH
2ON/A 0.163
Flow (L/min) Flow (L/sec) APL Pressure cmH
2O
 3 0.05 1.12
10 0.171.26
20 0.34 1.77
30 0.51 2.36
40 0.68 3.14
50 0.83 4.06
60 1.0 5.14
Disposal System Type Outlet Swivel Connector* Flow Range Pressure
Low flow, high vacuum DISS EVAC 36 ±4 SLPM at 300 
mmHg (12 inHg)300 mmHg (12 inHg) 
Minimum vacuum
High flow BS6834 50 - 80 SLPM 1.6 kPa at 75 SLPM
Venturi/Ejectorain. hose barb 30 - 100 SLPM n/a