E-Modules Technical Reference Manual 3rd Edition June 2012

Responsibility of the manufacturer GE Healthcare Finland Oy (GE) is responsible for the effects on safety, reliability and performance of the equipment only if: • assembly, extensions, readjustments, modifications, servicing and repairs are carried out by personnel authorized by GE. • the electrical installation of the monitor room complies with appropriate requirements. • the equipment is used in accordance with the "User's Guide" and serviced and maintained in accordance with the “Technical Reference Manual”. The manufacturer reserves the right to change product specifications without prior notice. Although the information in this manual is believed to be accurate and reliable, the manufacturer assumes no responsibility for its use.

Trademarks S/5, D-lite, D-lite+, Pedi-lite, Pedi-lite+, Mini D-fend, D-fend, D-fend+, MemCard, ComBar, ComWheel, EarSat, FingerSat, FlexSat, PatientO2, Entropy and Patient Spirometry are trademarks of GE Healthcare Finland Oy. Datex, Ohmeda, and OxyTip+ are trademarks of GE Healthcare Finland Oy and Datex-Ohmeda, Inc. A portion of the Entropy software is derived from the RSA Data Security, Inc. MD5 Message-Digest Algorithm.

Masimo SET Masimo SET is a licensed trademark of Masimo Corporation. All other product and company names are property of their respective owners.

Product availability Some of the products mentioned in this manual may not be available in all countries. Please, consult your local representative for the availability.

Master Table of Contents

Datex-Ohmeda E-Modules M1065282

Description Compact Airway Modules, E-CAiOVX, E-CAiOV,

1

E-CAiO, E-COVX, E-COV and E-CO PRESTN Modules, E-PRESTN, E-RESTN, E-PRETN

2

Patient Side Modules, E-PSM, E-PSMP rev. 01

3

Cardiac Output Modules E-COP rev. 01 and E-COPSv rev. 01

4

Pressure Module, E-P, Pressure Temp Module, E-PT

5

Dual Pressure Module, E-PP

6

Masimo Module, E-MASIMO

7

Nellcor Compatible Saturation Module, E-NSAT, E-NSATX

8

Single-width Airway Module, E-miniC

9

Tonometry Module, E-TONO

10

Entropy Module, E-ENTROPY

11

EEG Module, E-EEG rev.00 and EEG Headbox, N-EEG rev. 01

12

BIS Module, E-BIS rev. 01

13

NeuroMuscular Transmission Module, E-NMT

14

Device Interfacing Solution, N-DISxxx rev. 01

15

Interface Module, E-INT

16

Recorder Module, E-REC

17

Memory Module, E-MEM

18

Remote Controllers, K-REMCO rev. 01, K-CREMCO

19

Anesthesia record keeping keyboard, K-ARKB, Keyboard Interface Board, B-ARK and ARK Barcode Reader, N-SCAN

20

E-Modules, Spare Parts

21

i Document no. M1181405A

About this manual Notes to the reader This Technical Reference Manual is intended for service personnel and engineers who will service and maintain the Datex-Ohmeda E-Modules as well as the anesthesia record keeping keyboard, K-ARKB, remote controllers, K-REMCO and K-CREMCO, Device Interfacing Solution, N-DISxxx, keyboard interface board, B-ARK, and ARK barcode reader, N-SCAN. This Technical Reference Manual completes the S/5 Anesthesia Monitor and S/5 Critical Care Monitor Technical Reference Manual and the S/5 Compact Anesthesia Monitor and S/5 Compact Critical Care Monitor Technical Reference Manual. Later in this manual, the monitors may be referred to as AM, CCM, CAM and CCCM. The order code for the Datex-Ohmeda E-Modules Technical Reference Manual is M1065282. The order code for the S/5 Technical Reference Manuals CD is M1220141. S/5 AM, CCM Technical Reference Manual, S/5 CAM, CCCM Technical Reference Manual and Datex-Ohmeda E-Modules Technical Reference Manual are included on the CD. Each manual on the CD has an individual document number and is available for downloading from GE Common Document Library in Adobe Acrobat PDF format.

•

This Technical Reference Manual contains the information needed to maintain, service and troubleshoot these products. Instructions for visual and functional inspection, disassembly and reassembly as well as calibration of the modules are included. A service check form for each product is included in the slots.

•

In addition, this Technical Reference Manual contains detailed module specifications and descriptions on the technical performance and functioning of the modules.

•

Read the manual through and make sure that you understand the procedures described before servicing the modules. To avoid risks concerning safety or health, strictly observe the warning indications. If you need any assistance concerning the service, please do not hesitate to contact your authorized distributor.

For information on safety precautions and symbols on equipment, installation, planned maintenance and interfacing, refer to the AM and CCM Technical Reference Manual or the CAM and CCCM Technical Reference Manual. The manufacturer reserves the right to change product specifications without prior notice. Although the information in this manual is believed to be accurate and reliable, the manufacturer assumes no responsibility for its use. GE Healthcare assumes no responsibility for the use or reliability of its software in equipment that is not furnished by GE Healthcare.

Related documentation S/5 AM, CCM Technical Reference Manual S/5 CAM, CCCM Technical Reference Manual For more specific information about the clinical aspects refer to: S/5 monitor’s User’s Guide S/5 monitor’s User’s Reference Manual

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Conventions used Throughout this manual, the following conventions are used to distinguish procedures or elements of text:



Sign the check form after performing the procedure.

Hard Keys

Hard key names on the Command Board, the Remote Controller and modules are written in the following way: ECG.

Menu Items

Menu items are written in bold italic: ECG Setup.

‘Messages’

Messages displayed on the screen are written inside single quotes: ‘Please wait’.

“Sections”

When referring to different sections in the same manual, the section name is enclosed in double quotes: section “Cleaning and Service.”

“Other documents” When referring to different documents, the document name is enclosed in double quotes: refer to “User’s Reference Manual”. Hypertext links Hypertext links on PDF versions are written in blue color. WARNING

Warnings are written in the following way:

WARNING

Make sure that the electrodes, sensor and connectors do not touch any electrically conductive material, including earth.

CAUTION

Cautions are written in the following way:

CAUTION

The module electronics can only be repaired and calibrated at the factory.

NOTE

Notes are written in following way: NOTE: Handle all PC boards by their edges. In this manual, the word “select” means choosing and confirming.

Revision history Revision

Date

Comment

1st edition

10 May 2011

Initial

2nd edition

22 Sep 2011

Order code for paper manual added.

3rd edition

19 June 2012

E-PSM rev. 01, E-PSMP rev. 01, E-COP rev.01 and E-COPSv rev. 01 update.

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Compact Airway Modules S/5 Compact Airway Module, E-CAiOVX (Rev. 00) S/5 Compact Airway Module, E-CAiOV (Rev. 00) S/5 Compact Airway Module, E-CAiO (Rev. 00) S/5 Compact Airway Module, E-COVX (Rev.00) S/5 Compact Airway Module, E-COV (Rev. 00) S/5 Compact Airway Module, E-CO (Rev. 00)

Technical Reference Manual Slot

Conformity according to the Council Directive 93/42/EEC concerning Medical Devices amended by 2007/47/EEC. CAUTION: U.S. Federal law restricts this device to sale by or on the order of a licensed medical practitioner. Outside the USA, check local laws for any restriction that may apply. All specifications subject to change without notice. Document number M1027822-02 May 2, 2011

GE Healthcare Finland Oy Kuortaneenkatu 2, FI-00510 Helsinki Finland Tel: +358 10 39411 Fax: +358 9 1463310 www.gehealthcare.com © 2005, 2011 General Electric Company. All rights reserved.

Table of contents

Table of contents Table of contents

i

Table of figures

iii

Introduction

1

1

2

Specifications 1.1 1.2 1.3 1.4 1.5

2

Functional description 2.1

2.2

3

General specifications... 2 Typical performance... 2 Gas specifications... 3 1.3.1 Normal conditions... 3 1.3.2 Conditions exceeding normal... 4 Patient spirometry specifications... 4 1.4.1 Normal conditions... 4 1.4.2 Conditions exceeding normal... 5 Gas exchange specifications... 5 Measurement principle... 7 2.1.1 CO2, N2O, and agent measurement... 7 2.1.2 O2 measurement... 8 2.1.3 Patient spirometry... 9 2.1.4 Gas exchange measurement... 10 Main components... 11 2.2.1 Controls and connectors... 12 2.2.2 Gas sampling system... 13 2.2.3 TPX measuring unit... 15 2.2.4 PVX measuring unit... 16 2.2.5 CPU board... 17 2.2.6 OM board... 18

Service procedures 3.1

3.2

3.3

7

19

General service information... 19 3.1.1 OM measuring unit... 19 3.1.2 TPX measuring unit... 19 3.1.3 OM, TPX, and PVX measuring unit... 19 3.1.4 Serviceable parts... 19 Service check... 20 3.2.1 Recommended tools... 20 3.2.2 Recommended parts... 21 3.2.3 Planned Maintenance Kits... 21 3.2.4 Replacement procedures... 22 3.2.5 Visual inspection... 24 3.2.6 Functional inspection... 25 Disassembly and reassembly... 31 i Document no. M1027822-02

Datex-Ohmeda E-Modules

3.4

4

Troubleshooting 4.1

4.2 4.3 4.4 4.5 4.6

5

3.3.1 Before disassembly... 31 3.3.2 Required tools... 31 3.3.3 PVX unit... 31 3.3.4 Pump unit... 31 3.3.5 CPU board... 32 3.3.6 Software of CPU board... 32 3.3.7 Instructions after replacing software or CPU board... 32 Adjustments and calibrations... 33 3.4.1 Gas sampling flow rate measurement... 33 3.4.2 Gas sampling flow rate adjustment... 33 3.4.3 Gas calibration... 33

35

Troubleshooting charts... 35 4.1.1 CO2 measurement... 36 4.1.2 Patient spirometry... 37 4.1.3 Gas exchange... 39 Gas sampling system troubleshooting... 39 OM measuring unit troubleshooting... 40 PVX measuring unit troubleshooting... 40 CPU board troubleshooting... 40 Error messages... 41

Earlier revisions

Appendix A:

Service check form, Compact Airway Modules

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42 A-1

List of figures

Table of figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14 Figure 15

TPX sensor principle... 7 Absorbance of N2O and CO2 ... 7 Infrared absorbance of AAs ... 8 O2 measurement principle ... 8 Front of Compact Airway Module, E-CAiOVX, and the back of the module...12 Absorber ...13 Gas sampling system layout...14 Gas tubing layout...15 TPX measuring unit ...15 OM measuring unit...16 PVX measuring unit...16 Signal processing ...17 Control logic...18 Calibration data stored in EEPROM...18 Pneumatic unit and reference gas connection block ...25

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Compact Airway Modules

Introduction This Technical Reference Manual slot provides information for the maintenance and service of the Datex-Ohmeda S/5 Compact Airway modules. The Compact Airway modules are double width plug-in modules. E-CO, E-COV, E-COVX, E-CAiO, E-CAiOV, E-CAiOVX and E-CAiOVX/SERVICE/SERVICE are designed for use with the S/5 Monitors. Later in this manual modules may be referred to without S/5 for simplicity. The service menu is described in a separate “Service Menu“ slot and the spare part lists in the “E-Modules Spare Parts” slot. The Compact Airway modules provide airway and respiratory measurements. Letters in the module name stand for: C = CO2 and N2O, O = patient O2, V = patient spirometry, X = gas exchange, A = anesthetic agents, and i = agent identification

About E-CAiOVX/SERVICE module The E-CAiOVX/SERVICE module is meant for service purposes only. It can be used as a loan module, if the module in the hospital should be sent to the factory for repair. The specifications that apply to the E-CAiOVX apply also to the E-CAiOVX/SERVICE module. Module differences: the color of the front mask is green, the front panel has a “SERVICE” text and there are no front panel keys equipped.

Table 1

Options for Compact Airway modules

Modules

Parameters / measurements CO2

N2O

E-CAiOVX

X

X

X

X

X

X

E-CAiOV

X

X

X

X

X

X

E-CAiO

X

X

X

X

X

E-COV

X

X

X

X

E-COVX

X

X

X

X

X

E-CO

X

X

X

E-CAiOVX/SERVICE

X

X

X

X

X

O2

Anesthetic Agent ID Spirometr agents y

X

X

Gas exchange X

NOTE: Do not use identical modules in the same monitor simultaneously. The E-miniC, E-CO, E-COV, E-COVX, E-CAiO, E-CAiOV, E-CAiOVX and E-CAiOVX/SERVICE and the M-miniC, M-C, M-CO, M-COV, M-COVX, M-CAiO, M-CAiOV, M-CAiOVX and M-CAiOVX/SERVICE are considered identical modules. NOTE: The Compact Airway Module or Single-Width Airway Module and Airway Module, G-XXXX, cannot be used simultaneously in the same monitor. NOTE: The Compact Airway modules cannot be used in the Extension Frame, F-EXT4. NOTE: Anesthetic agents and N2O values are not displayed with Critical Care main software, but when present in the module they are calculated for compensation of CO2 and O2.

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1

Specifications

1.1 General specifications Module size, W x D x H Module weight Operating temperature Storage temperature Atmospheric pressure

Relative humidity

75 x 228 x 112 mm / 3.0 x 9.0 x 4.4 in 1.6 kg / 3.5 lb. +10 to +40 °C -25 to +70 °C 666 to 1060 hPa / (67 to 106 kPa) (500 to 800 mmHg) (666 to 1060 mbar) 10 to 95% non-condensing (in airway 0 to 100%, condensing)

Power consumption

12.6 W Prms, 14.6 W momentary

Protection against electrical shock

Type BF

1.2 Typical performance CO2 Measurement range Measurement rise time Accuracy Gas cross effects

0 to 15 vol% (0 to 15 kPa, 0 to 113 mmHg) < 400 ms typical (0.2 vol% +2% of the reading) e.g. Reading 5.0 % accuracy = ± (0.2 + 0.1); = ± 0.3 vol% < 0.2 vol% (O2, N2O, anesthetic agents)

O2 Measurement range Measurement rise time Accuracy Gas cross effects

0 to 100 vol% < 400 ms typical ± (1 vol% + 2% of the reading) < 1 vol%; anesthetic agents < 2 vol%; N2O

O2 Fi-Et difference

resolution 0.1 vol%

Measurement range Measurement rise time Accuracy

0 to 100% < 400 ms typical ± (2 vol% + 2% of the reading) (0%<N2O<85%) ± (2 vol% + 8% of the reading) (85%<N2O<100%) < 2 vol%; anesthetic agents

N2O

Gas cross effects

Respiration Rate (RR) Measurement range Detection criteria

2 Document no. M1027822-02

4 to 60 breaths/min 1% variation in CO2

Compact Airway Modules

Anesthetic Agents (AA) Measuring range Hal, Enf, Iso Sev Des Measurement rise time Gas cross effects

0 to 6 vol% 0 to 8 vol% 0 to 20 vol% <600 ms typical (<1000 ms for Hal, typical) < 0.15 vol% N2O

Resolution is two digits, when the AA concentration is below 1.0 vol%. If AA concentration is below 0.1 vol%, 0.0% is displayed.

Agent identification Identification threshold 0.15 vol% typical Identification time < 20 s (for pure agents) Mixture identification threshold for 2. agent: 0.2 vol% +10% of total conc.

MAC Range Equation:

0...9.9 MAC

Formula 1 where x(AA): Hal=0.75%, Enf=1.7%, Iso=1..15%, Sev=2.05%, Des=6.0%

1.3 Gas specifications Airway humidity Sampling rate Sampling delay

0...100%, condensing 200 ±20 ml/min. (sampling line 2-3 m, normal conditions) 2.5 seconds typical with a 3 m sampling line

Total system response time

2.9 seconds typical with a 3 m sampling line, including sampling delay and rise time

Display update rate Warm up time

breath-by-breath 2 min. for operation with CO2, O2, and N2O 5 min. for operation of anesthetic agents 30 min. for full specifications

Gas values are measured in ATPD conditions (ambient temperature and pressure, dry). When CO2 is displayed as a partial pressure (kPa, mmHg), the value can be alternatively shown as wet (BTPS, body temperature and pressure saturated). Automatic compensation for barometric pressure , CO2-N2O and CO2-O2 collision broadening effect. Auto zeroing interval

Immediately after calibrating the gas sensor and 2, 5, 10, 15, 30, 45, 60 minutes after start-up, then every 60 minutes

1.3.1 Normal conditions Accuracy specifications apply in normal conditions (after 30 minutes warm-up period): Ambient temperature Ambient pressure Ambient humidity

18 to 28 °C, within ±5 °C of calibration 500 to 800 mmHg, ±50 mmHg of cal. 20 to 80% RH, ±20% RH of cal.

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Non-disturbing gases Ethanol C2H5OH

< 0.3%

Acetone Methane CH4

< 0.3% < 0.3%

Freon 21 Freon R134A Nitrogen N2

< 1% <1%

Carbon monoxide CO Nitric Oxide NO water vapor Maximum effect on readings CO2

< 0.2 vol%

O2, N2O

< 2 vol%

anesthetic agents Effect of Helium

< 0.15 vol% decreases CO2 readings < 0.6 vol% typically decreases O2 readings < 3 vol% typically

Effect of Xenon

decreases CO2 readings < 0.4 vol% typically

< 200 ppm

1.3.2 Conditions exceeding normal Accuracy specifications under the following conditions; nopq: n Ambient temperature Ambient pressure Ambient humidity

10 to 40 °C, within ±5 °C of calibration 500 to 800 mmHg, ±50 mmHg of calibration 10 to 98% RH, ±20% RH of calibration

o During warm-up 2 to 10 minutes (anesthetic agents 5-10 minutes), under normal conditions p During warm-up 10 to 30 minutes, under normal conditions q N2O > 85%, under normal conditions Accuracy under different conditions (see above) Condition n and p

Condition o

CO2

±(0.3 vol% + 4% of reading) (at 5 vol% error ±0.5 vol%)

±(0.4 vol% + 7% of reading) (at 5 vol% error ±0.75 vol%)

O2

(2 vol% + 2% of reading)

±(3 vol% + 3% of reading)

N2O

±(3 vol% + 3% of reading)

±(3 vol% + 5% of reading)

Agents: Hal, Enf, Iso, Sev, Des

±(0.2 vol% + 10% of reading) ±(0.3 vol% + 10% of reading)

Condition q

± (2vol% + 8% of reading)

1.4 Patient spirometry specifications 1.4.1 Normal conditions Accuracy specifications apply in normal conditions (after 10 minutes warm-up period): Ambient temperature Ambient pressure Ambient humidity Airway humidity

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10 to 40 °C 500 to 800 mmHg 10 to 98% RH 10 to 100% RH

Compact Airway Modules

Respiration rate I:E ratio Intubation tube

4 to 35 breaths/min (adults) 4 to 50 breaths/min (pediatric) 1:4.5 to 2:1 5.5 to 10 mm (adults), 3...6 mm (pediatric)

Airway pressures (Paw, Ppeak, Pplat, PEEPe, PEEPiStat, PEEPiDyn, Pmean) Measurement range

-20 to +100 cmH2O

Resolution

0.5 cmH2O

Accuracy

±1 cmH2O

Airway flow Measurement range (for both directions)

1.5 to 100 l/min (adults) 0.25 to 25 l/min (pediatric)

Tidal volume Measurement range Resolution Accuracy

150 to 2000 ml (adults), 15...300 ml (pediatric) 1 ml ±6% or 30 ml (adult), ±6% or 4 ml (pediatric)

Minute volume Measurement range Resolution

2 to 20 l/min (adults), 0.5...5 l/min (pediatric) 0.1 l/min

Compliance Measurement range

4 to 100 ml/cmH2O (adult), 1...100 ml/cmH2O (pediatric)

Resolution

1 ml/cmH2O (adult), 0.1 ml/cmH2O (pediatric)

Airway resistance Measurement range

0 to 40 cmH2O/ l/s

Resolution

1 cmH2O/ l/s

Other parameters Specifications apply in conditions listed in patient spirometry specifications.

Dead space of the sensor 9.5 ml (adult), 2.5 ml (pediatric)

Resistance of the sensor 0.5 cmH2O at 30 l/min (adult), 1.0 cmH2O at 10 l/min (pediatric)

1.4.2 Conditions exceeding normal Accuracy specifications under the following condition (during warm-up 2 to 10 minutes):

Airway Pressure (Paw) Accuracy

±2 cmH2O

Tidal volume Accuracy

±10% or 100 ml (adult), ±10% or 10 ml (pediatric)

1.5 Gas exchange specifications Mathematical integration of airway flow and gas concentration for intubated, mechanically ventilated and/or partly spontaneously breathing patients. NOTE: These specifications apply only, when a 2 meter gas sampling line is used, and a Y-piece with a physical dead space less than 8 ml.

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NOTE: These specifications only apply, if the FiO2 level delivered to the patient is varying by less NOTE: than 0.2% at the measurement point during the inspiratory cycle.

VO2 and VCO2 Measurement range Resolution Accuracy

50 to 1000 ml/min 10 ml/min ±10% or 10 ml/min; when FiO2 < 65% ±15% or 15 ml/min; when 65% < FiO2 < 85%

RQ Measurement range Resolution

6 Document no. M1027822-02

0.6...1.2 0.05

Compact Airway Modules

2

Functional description

2.1 Measurement principle 2.1.1 CO2, N2O, and agent measurement TPX is a side stream gas analyzer, measuring real time concentrations of CO2, N2O and anesthetic agents (Halothane, Enflurane, Isoflurane, Desflurane, and Sevoflurane).

6DPSOH FKDPEHU

6DPSOH JDVRXW

Figure 1

6DPSOH JDVLQ

7KHUPRSLOH GHWHFWRUV

73;BVHQVRUBSULQFSOHYVG

7HPSVHQVRU

TPX sensor principle

Anesthetic agents or mixtures of two anesthetic agents are automatically identified and concentrations of the identified agents are measured. TPX also detects mixtures of more than two agents and issues an alarm. TPX is a non dispersive infrared analyzer, measuring absorption of the gas sample at seven infrared wavelengths, which are selected using optical narrow band filters. The infrared radiation detectors are thermopiles.

absorbance_N2O_CO2.vsd

Concentrations of CO2 and N2O are calculated from absorption measured at 3-5 μm.

Figure 2

Absorbance of N2O and CO2

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absorbance_AA.vsd

Identification of anesthetic agents and calculation of their concentrations is performed by measuring absorptions at five wavelengths in the 8-9 μm band and solving the concentrations from a set of five equations.

Figure 3

Infrared absorbance of AAs

The measuring accuracy is achieved utilizing numerous software compensations. The compensation parameters are determined individually for each TPX during the factory calibration.

2.1.2 O2 measurement The differential oxygen measuring unit uses the paramagnetic principle in a pneumatic bridge configuration. The signal picked up with a differential pressure transducer is generated in a measuring cell with a strong magnetic field that is switched on and off at a frequency of 165 Hz. The output signal is a DC voltage proportional to the O2 concentration difference between the two gases to be measured.

(OHFWURPDJQHW

0LFURSKRQH 6DPSOHLQ 5HIHUHQFHLQ

Figure 4

8 Document no. M1027822-02

O2 measurement principle

6ZLWFKHG PDJQHWLF ILHOG

2BPHDVBSULQFLSOHYVG

0L[WXUH RXW

Compact Airway Modules

2.1.3 Patient spirometry In mechanical ventilation, breaths are delivered to the patient by a ventilator with a proper tidal volume (TV), respiration rate (RR), and inspiration / expiration ratio in time (I:E) determined by the settings of the ventilator. The Patient Spirometry monitors patient ventilation. The following parameters are displayed: − − − −

Expiratory and inspiratory tidal volume (TV) in ml Expiratory and inspiratory minute volume (MV) in l/min Expiratory spontaneous minute volume in l/min Inspiration/expiration ratio (I:E)

Airway pressure − −

Peak pressure (Ppeak) Mean airway pressure (Pmean); available only in S/5 Critical Care and Compact Critical Care monitors − End inspiratory pressure (Pplat) − PEEPi, PEEPe; available only in S/5 Critical Care and Compact Critical Care monitors − Total positive end expiratory pressure (PEEPtot); available only in S/5 Anesthesia and Compact Anesthesia monitors − Real time airway pressure waveform (Paw) − Static Positive end expiratory pressures (Static PEEPi and Static PEEPe); available only in S/5 Critical Care and Compact Critical Care monitors − Static Plateau pressure (Static Pplat); available only in S/5 Critical Care and Compact Critical Care monitors − Static Compliance (Static Compl); available only in S/5 Critical Care and Compact Critical Care monitors PEEP, Ppeak, Pmean, and Pplat are measured by a pressure transducer on the PVX board. Atmospheric pressure is used as a reference in measurement. The pressure measurement is made from the airway part that is closest to the patient between the patient circuit and intubation tube. PEEPi=intrinsic PEEP, PEEPtot-PEEPe Static pressure measurement maneuvers are automatically identified based on an increased zero flow period at the end of the inspiration or expiration. Static Compliance is calculated, if Static PEEP and Static Pplat measurements were made within a 2 minute period.

Airway flow − Real time flow waveform (V') − Compliance (Compl) − Airway resistance (Raw) − Pressure volume loop − Flow volume loop The measurement is based on measuring the kinetic gas pressure and is performed using the Pitot effect. A pressure transducer is used to measure the Pitot pressure. The pressure signal obtained is linearized and corrected according to the density of the gas. Speed of flow is calculated from these pressure values and the TV value is then integrated. The MV value is calculated and averaged using TV and RR (respiratory rate) values.

Compliance and airway resistance Compliance is calculated for each breath from the equation

Formula 2

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Datex-Ohmeda E-Modules

Compliance describes how large a pressure difference is needed to deliver a certain amount of gas to the patient. The airway resistance, Raw, is calculated using an equation that describes the kinetics of the gas flow between the lungs and the D-lite. The equation states that the pressure at the D-lite can at any moment of the breath be approximated using the equation Formula 3

where P(t), V’(t) and V(t) are the pressure, flow and volume measured at the D-lite at a time t, Raw is the airway resistance, Compl is the compliance and PEEPe+PEEPi is the total positive end expiratory pressure (PEEPtot).

D-lite Patient Spirometry uses specific sensors called D-lite+/D-lite and Pedi-lite+/Pedi-lite flow sensors. Different types of sensors are available: adult sensor for measuring adults and pediatric sensor for children. Both are available as reusable and disposable versions. D-lite and Pedi-lite adapters are designed to measure kinetic pressure by a two-sided Pitot tube. Velocity is calculated from pressure difference according to Bernoulli's equation. Flow is then determined using the calculated velocity.

(from Bernoulli's equation)

Formula 4

where: F = flow (l/min), v = velocity (m/s), A = cross area (m2), dP = pressure difference (cmH2O), ρ = density (kg/m3) Finally the volume information is obtained by integrating the flow signal.

2.1.4 Gas exchange measurement The gas exchange measurement uses the D-lite flow sensor and the gas sampler. The basic data which is needed to obtain O2 consumption and CO2 production are volumes and concentrations. Concentrations have been corrected for delay and deformation during the transport of the gas sample in a sidestream gas measurement sensor. To obtain the amount of O2 consumed in ml/min, the amount which is exhaled is subtracted from the amount that is inhaled. To obtain the amount of CO2 produced in ml/min, the amount which is inhaled is subtracted from the amount that is exhaled. These amounts can be obtained by multiplying each measured volume piece (dv) by the corresponding gas concentration:

Formula 5

and

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Compact Airway Modules

Formula 6

Using inspiratory and expiratory minute volumes MVi and MVe and volume-weighted inspiratory concentrations fi and fe, these equations can be rewritten as: Formula 7 Formula 8

To obtain results which are less sensitive to errors in volume measurements, the so-called Haldane transformation is used. This means taking advantage of the fact that the patient is not consuming nor producing nitrogen: the amount of nitrogen inhaled is equal to the amount exhaled fiN2 × MVi=feN2×MVe. VO2 and VCO2 can then be written as: Formula 9

Formula 10

with fHald = (1-fiCO2 – fiO2 – fiN2O - fiAne1 – fiAne2) / (1-feCO2 – feO2 – feN2O - feAne1 – feAne2)

Formula 11

with Un=Urea Nitrogen Excretion = 13 g/day (for adults only).

2.2 Main components The compact airway modules consist of:

• • • • • • •

Gas sampling system TPX measuring unit OM measuring unit PVX measuring unit CPU board OM board PVX board

11 Document no. M1027822-02