GE HEALTHCARE E-PSMP, E-PRESTN, E-PSM, E-RESTN, E-PRETN Technical Manual
GE Healthcare
Module Frames and Modules
Technical Manual
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.
English
Order code
#2062973-004 paper
October 5, 2016
© 2013 - 2016 General Electric Company. All rights reserved.
Master table of contents
Module Frames and Modules
Technical Manual
Order code
#2062978-001 DVD
#2062978-002 DVD 510(k)
#2062973-004 paper
Description Tab
About this manual 1
PRESTN Modules, E-PRESTN, E-RESTN, E-PRETN
Patient Side Modules, E-PSM, E-PSMP Rev.01
PiCCO Module, E-PiCCO 3
Cardiac Output Modules E-COP and E-COPSv Rev. 01 4
Pressure Module, E-P, Pressure Temp Module, E-PT,
Dual Pressure Module, E-PP
Masimo Module, E-MASIMO 6
Nellcor Compatible Saturation Module, E-NSATX 7
Respiratory Modules, E-sCAiOVX, E-sCAiOV, E-sCAiO,
E-sCOVX, E-sCOV, E-sCO
Compact Airway Modules, E-CAiOVX, E-CAiOV, E-CAiO,
E-COVX, E-COV and E-CO
Single-width Airway Module, E-miniC 10
Entropy Module, E-ENTROPY Rev. 01 11
EEG Module, E-EEG and EEG Headbox, N-EEG 12
BIS Module, E-BIS Rev. 01 13
NeuroMuscular Transmission Module, E-NMT Rev. 01 14
2
5
8
9
Module Frames F5, F7 15
PDM Module v2 16
2062973-004
Module Frames and Modules
For your notes:
2062973-004
Table of contents
Table of contents
1 About this manual 1-1
1.1 Intended use of the manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
1.2 Intended audience of the manual. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
1.3 Third party trademarks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
1.4 ESD awareness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
1.5 Service requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
1.5.1 Equipment identification. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
1.5.2 Serial number label. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
1.5.3 Device plate location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
1.5.4 Access to Webmin. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
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Module Frames and Modules
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2062973-004
1 About this manual
1.1 Intended use of the manual
This Module Frames and Modules Technical Manual must be used in conjunction with the
CARESCAPE modular monitor’s technical manual for important safety information.
This manual contains instructions necessary to perform planned and corrective maintenance
to the parameter modules and module frames. Use it as a guide for maintenance and repairs
considered field repairable.
Where necessary the manual identifies additional sources of relevant information and
technical assistance.
See the patient monitor’s technical manual for an overview of the patient monitoring system,
information needed for system installation and for planned and corrective maintenance.
See the supplemental information manual for the technical specifications, default settings and
compatibility information, including electromagnetic compatibility.
See the patient monitor’s user's manual for the instructions necessary to operate the device
safely in accordance with its function and intended use.
About this manual
1.2 Intended audience of the manual
This manual is intended for service representatives and technical personnel who install,
maintain, troubleshoot, or repair this device.
1.3 Third party trademarks
All other product and company names are the property of their respective owners.
1.4 ESD awareness
The system complies with IEC 60601-1-2:2001 + A:2004.
In accordance with IEC 60601-1-2, modules marked with the ESD warning symbol (IEC
60417-5134) require user training in ESD awareness and prevention as follows:
• The contents of the training are specified in the local ESD Control Program Plan, issued in
accordance with IEC 61340-5-1. The training should at least include an introduction to
ESD and its impacts on electrical devices and how to prevent it by using appropriate
personal protection equipment, proper work practices and tools.
1.5 Service requirements
General service requirements and qualification requirements for the service personnel.
Follow the service requirements listed below.
−
Refer equipment servicing to GE authorized service personnel only.
−
Any unauthorized attempt to repair equipment under warranty voids that warranty.
−
It is the user’s responsibility to report the need for service to GE or to one of their
authorized agents.
−
Failure on the part of the responsible individual, hospital, or institution using this
equipment to implement a satisfactory maintenance schedule may cause undue
equipment failure and possible health hazards.
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Module Frames and Modules
− Regular maintenance, irrespective of usage, is essential to ensure that the equipment will
always be functional when required.
1.5.1 Equipment identification
Every GE device has a unique serial number for identification. A sample of the information
found on a serial number label is shown below.
Description
A product code
B year manufactured
C fiscal week manufactured
D production sequence number
E manufacturing site
F miscellaneous characteristic
1.5.2 Serial number label
An example of a serial number label of an E-module is shown below.
Description
TYPE Device type e.g. E-NMT
SN Serial number
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1.5.3 Device plate location
The device plate is located between the docking rails of the PDM module and on the inside of
the module frames F5 and F7.
About this manual
Figure 1 Device plate location, Patient Data Module and module frames
The device plate is located beside the docking rails of the E-PSM and E-PSMP modules and on
the left side of the plug-in E-modules.
Figure 2 Device plate location, E-PSM and E-modules
1.5.4 Access to Webmin
Webmin can be accessed locally through the CARESCAPE monitor or remotely from a
configured service laptop connected to the CARESCAPE monitor.
For information about Webmin, see the CARESCAPE monitor’s technical manual.
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Module Frames and Modules
For your notes:
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Hemodynamic Modules E-PRESTN, E-RESTN, E-PRETN (Rev. 00) E-PSMP, E-PSM (Rev. 01)
Technical Manual
2
Table of contents
Table of contents
1 Product overview 2-1
1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
1.2 Measurement principle. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
1.2.1 ECG. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
1.2.2 Respiration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
1.2.3 Invasive blood pressure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
1.2.4 Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
1.2.5 Pulse oximetry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
1.2.6 NIBP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5
1.3 Main components. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
1.3.1 Controls and connectors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
1.3.2 E-PSM(P) and E-(P)RE(S)TN modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8
1.3.3 ECG board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-9
1.3.4 STP board. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-11
1.3.5 NIBP board. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-16
2 Configuration 2-20
2.1 STP/TP /ST-Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-20
2.1.1 Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-20
3 Maintenance and checkout 2-22
3.1 Replacement of planned maintenance parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-22
3.1.1 Required parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-22
3.1.2 Replacement procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-22
3.2 Visual inspections. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-22
3.3 Electrical safety tests. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-23
3.4 Functional check. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-23
3.4.1 Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-23
3.4.2 ECG tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-27
3.4.3 Impedance respiration tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-27
3.4.4 Invasive pressure tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-28
3.4.5 Temperature tests. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-28
3.4.6 SpO2 tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-28
3.4.7 NIBP tests. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-29
3.4.8 Test completion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-30
4 Calibration and adjustments 2-31
4.1 Invasive pressure calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-31
4.1.1 Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-31
4.1.2 Procedure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-32
4.2 Temperature calibration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-33
4.2.1 Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-33
4.2.2 Procedure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-33
4.3 NIBP calibration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-34
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4.3.1 Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-35
4.3.2 Procedure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-35
5 Troubleshooting 2-38
5.1 Visual inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-38
5.2 Troubleshooting checklist . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-38
5.3 Service Interface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-39
5.3.1 Configuration Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-39
5.3.2 Device Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-39
5.3.3 Log files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-39
5.4 Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-40
5.4.1 ECG. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-40
5.4.2 Impedance respiration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-42
5.4.3 Invasive Pressure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-42
5.4.4 Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-44
5.4.5 SpO2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-44
5.4.6 NIBP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-45
5.5 Troubleshooting chart. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-49
5.5.1 Invasive Pressure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-49
5.5.2 Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-49
6 Disassembly and reassembly 2-50
6.1 Disassembly guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-50
6.1.1 ESD precautions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-50
6.1.2 Before disassembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-50
6.1.3 Required tools. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-51
6.2 Disassembling and reassembling procedure, E-PRESTN, E-PRETN, E-RESTN . . . . . . . . . . . 2-51
6.2.1 Removing the pump unit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-57
6.2.2 Replacing the NIBP air filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-58
6.3 Disassembling and reassembling procedure, E-PSMP and E-PSM. . . . . . . . . . . . . . . . . . . . . 2-58
6.3.1 Removing the pump unit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-62
6.3.2 Removing the manifold unit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-63
6.3.3 Removing the module bus connector. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-64
6.3.4 Replacing the NIBP air filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-65
7 Service parts 2-66
7.1 Ordering parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-66
7.2 E-PRESTN, E-PRETN, E-RESTN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-67
7.2.1 Front cover for E-PRESTN, E-PRETN, E-RESTN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-70
7.3 Patient Side Modules, E-PSM, E-PSMP (Rev. 01). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-72
7.4 Patient Side Modules, E-PSM, E-PSMP (Rev. 00). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-74
7.4.1 Front panel labeling, E-PSM(P) (Rev. 00 and 01) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-75
7.4.2 Spare parts for PSM mounts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-76
8 Earlier revisions 2-77
Maintenance check form 2-79
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Hemodynamic Modules E-PRESTN, E-RESTN, E-PRETN, E-PSMP, E-PSM
1 Product overview
1.1 Introduction
This document provides information for the maintenance and service of the Patient Side
Modules E-PSMP and E-PSM, and the double-width plug-in hemodynamic modules, E-PRETN,
E-PRESTN and E-RESTN.
These modules provide general hemodynamic parameters.
Figure 1 Patient Side Module, E-PSMP, and Hemodynamic Module, E-PRESTN.
Parameter E-PSMP E-PSM E-PRESTN E-RESTN E-PRETN
ECG
Impedance respiration
Two invasive blood
pressures
Two temperatures
Pulse oximetry
NIBP
XXX XX
XXX XX
XX X
XXX XX
XXX X
XXX XX
Equipment safety symbols
Safety symbol for the E-PSMP and E-PSM modules:
This symbol on the module refers to defibrillator precautions. To ensure
protection against the effects of cardiac defibrillator discharge, always use the
recommended cables and leadwires only (see the supplemental information
manual). Using other cables or leadwires may result in damage to the
equipment and compromise patient and/or user safety.
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Safety symbol for the E-PRESTN, E-RESTN, and E-PRETN modules:
When displayed on the module, indicates that protection against cardiac
defibrillator discharge is due in part to the accessories for pulse oximetry (SpO
temperature (T) and invasive pressure (P) measurement.
1.2 Measurement principle
1.2.1 ECG
Electrocardiography analyzes the electrical activity of the heart by measuring the electrical
potential produced with electrodes placed on the surface of the body.
ECG reflects:
• electrical activity of the heart
• normal/abnormal function of the heart
• effects of anesthesia on heart function
),
2
• effects of surgery on heart function
See the patient monitor’s user’s manual for electrodes’ positions and other information.
1.2.2 Respiration
Impedance respiration is measured across the thorax between ECG electrodes. The respiration
signal is made by supplying current between the electrodes and by measuring the differential
current from the electrodes. The signal measured is the impedance change caused by
breathing. The respiration rate is calculated from these impedance changes, and the
respiration waveform is displayed on the screen.
1.2.3 Invasive blood pressure
To measure invasive blood pressure, a catheter is inserted into an artery or vein. The invasive
pressure setup, consisting of a connecting tubing, a pressure transducer, an intravenous bag
of normal saline, all connected together by stopcocks, is attached to the catheter. The
transducer is placed at the same level with the heart, and is electrically zeroed.
The transducer is a piezo-resistive device that converts the pressure signal to a voltage. The
monitor interprets the voltage signal so that pressure data and pressure waveforms can be
displayed.
1.2.4 Temperature
The temperature is measured by a probe whose resistance varies when the temperature
changes, called NTC (Negative Temperature Coefficient) resistor.
The resistance can be measured by two complementary methods:
• Applying a constant voltage across the resistor and measuring the current that flows
through it.
• Applying a constant current through the resistor and measuring the voltage that is
generated across it.
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These modules use the constant current method. The NTC-resistor is connected in series with a
SaO2frac
HbO
2
HbO2Hb Dyshemoglobin++
-----------------------------------------------------------------------------=
SaO2func
HbO
2
HbO2Hb+
----------------------------=
normal resistor and a constant voltage is applied across them. The temperature dependent
voltage can be detected at the junction of the resistors, thus producing the temperature signal
from the patient. The signal is amplified by analog amplifiers and further processed by digital
electronics.
1.2.5 Pulse oximetry
A pulse oximeter measures the light absorption of blood at two wavelengths, one in the near
infrared (about 940 nm) and the other in the red region (about 660 nm) of the light spectrum.
These wavelengths are emitted by LEDs in the SpO
peripheral tissue and is finally detected by a PIN-diode opposite the LEDs in the probe. The
pulse oximeter derives the oxygen saturation (SpO
relationship between the relative absorption at the two wavelengths and the arterial oxygen
saturation SaO2.
In order to measure the arterial saturation accurately, pulse oximeters use the component of
light absorption giving variations synchronous with heart beat as primary information on the
arterial saturation.
A general limitation of pulse oximetry is that due to the use of only two wavelengths, only two
hemoglobin species can be discriminated by the measurement.
The modern pulse oximeters are empirically calibrated either against fractional saturation
SaO
frac;
2
Hemodynamic Modules E-PRESTN, E-RESTN, E-PRETN, E-PSMP, E-PSM
probe, the light is transmitted through
2
) using an empirically determined
2
Formula 1
or against functional saturation SaO
func;
2
Formula 2
Functional saturation is more insensitive to changes of carboxyhemoglobin and
methemoglobin concentrations in blood.
The oxygen saturation percentage SpO
functional saturation SaO
measurement relative to SaO
func. The advantage of this method is that the accuracy of SpO2
2
func can be maintained even at rather high concentrations of
2
measured by the module is calibrated against
2
carboxyhemoglobin in blood. Independent of the calibration method, pulse oximeters are not
able to correctly measure oxygen content of the arterial blood at elevated carboxyhemoglobin
or methemoglobin levels.
Plethysmographic pulse wave
The plethysmographic waveform is derived from the IR signal and reflects the blood pulsation
at the measuring site. Thus the amplitude of the waveform represents the perfusion.
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Module Frames and Modules
PSM_absorption_of_infrared.vsd
Emitter
Detector
SpO2 sensor connector
IRED
RED
Pulse rate
The pulse rate calculation is done by peak detection of the plethysmographic pulse wave. The
signals are filtered to reduce noise and checked to separate artifacts.
Figure 2 Absorption of infrared light in the finger
Figure 3 Pulse oximetry probe parts layout and schematic diagram
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1.2.6 NIBP
Hemodynamic Modules E-PRESTN, E-RESTN, E-PRETN, E-PSMP, E-PSM
The standard probe is a finger clamp probe which contains the light source LEDs in one half
and the photodiode detector in the other half. Different kinds of probes are available from GE
Healthcare.
NIBP (Non-Invasive Blood Pressure) is an indirect method for measuring blood pressure.
The NIBP measurement is performed according to the oscillometric measuring principle. The
cuff is inflated with a pressure slightly higher than the presumed systolic pressure, and deflated
at a speed based on the patient’s pulse, collecting data from the oscillations caused by the
pulsating artery. Based on these oscillations, values for systolic, mean, and diastolic pressures
are calculated.
The following parts are necessary for the NIBP measurement:
• a parameter module
• twin hose (adult or infant model)
• blood pressure cuffs (various sizes)
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Module Frames and Modules
1.3 Main components
1.3.1 Controls and connectors
Figure 4 Front and back panel connectors of E-PRESTN module
Module keys Module Description
Auto On/Off
Start Cancel
Zero P1
Zero P2
Connector Module Description
NIBP E-PRESTN, E-PRETN, E-RESTN NIBP connector (black)
P1-P2 E-PRESTN, E-PRETN InvBP connector (red)
T1-T2 E-PRESTN, E-PRETN, E-RESTN Temperature connector (brown)
SpO
2
ECG E-PRESTN, E-PRETN, E-RESTN ECG and impedance respiration
D25 connector E-PRESTN, E-PRETN, E-RESTN Module bus connector
E-PRESTN, E-PRETN, E-RESTN Starts and stops autocycling NIBP
measurements
Starts a single NIBP measurement,
and cancels any measurement.
E-PRESTN, E-PRETN Zeroes P1
Zeroes P2
E-PRESTN, E-RESTN SpO2 connector (blue)
connector (green)
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Hemodynamic Modules E-PRESTN, E-RESTN, E-PRETN, E-PSMP, E-PSM
Figure 5 Front panel and connectors of E-PSMP module and the back of the
module
Module keys Module Description
Auto On/Off
Start Cancel
Zero P1
Zero P2
Connector Module Description
NIBP E-PSM, E-PSMP NIBP connector (black)
P1-P2 E-PSMP InvBP connector (red)
T1-T2 E-PSM, E-PSMP Temperature connector (brown)
SpO
2
ECG E-PSM, E-PSMP ECG and impedance respiration
E-PSM, E-PSMP Starts and stops autocycling NIBP
measurements
Starts a single NIBP measurement,
and cancels any measurement.
E-PSMP Zeroes P1
Zeroes P2
E-PSM, E-PSMP SpO2 connector (blue)
connector (green)
Tab for removing the module E-PSM, E-PSMP Detachment tab (gray)
5 pin connector E-PSM, E-PSMP Module bus connector
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Module Frames and Modules
1.3.2 E-PSM(P) and E-(P)RE(S)TN modules
The modules contain three main PC boards, the STP board, the ECG board, and the NIBP board.
Each of these boards contain a processor and software in the processor flash memory. The
boards produce their own supply voltages from the Vmod 13.8-16 V line that is available via
the module bus connector. In addition to this, the NIBP board provides +5V for the ECG and STP
board non-isolated side components. The NIBP board provides also the synchronization signal
for the ECG and STP board power supplies.
There are two input boards; the STP input board and the ECG input board attached to the front
panel of the module. The front panel has five connectors and four keys. There is one connector
for two temperature measurements, one for two invasive blood pressure measurements, one
for ECG, one for NIBP, and one for SpO2 measurement. The NIBP connector includes two
plungers for NIBP hose identification. The keys are for NIBP Auto On/Off, NIBP Start/Cancel, P1
zero, and P2 zero.
NOTE: The connectors and keys depend on the module variant, and some variants may not
have all the mentioned connectors and keys.
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1.3.3 ECG board
The ECG measurement consists of the functions shown in the figure6. All functions are located
in the ECG board except the ECG input unit.
Hemodynamic Modules E-PRESTN, E-RESTN, E-PRETN, E-PSMP, E-PSM
Figure 6 ECG measurement block diagram
ECG input unit
The ECG input unit consists of the front panel connector and the ECG input connector board
with the high voltage protection resistors. The connector for the ECG cable is a green 11-pin
rectangle shaped connector.
Input protection and filtering
The input protection is implemented with high voltage protection resistors in the ECG input unit
and with protection diodes in the ECG board. The input filtering for ECG measurement is done
with passive RC filtering.
ECG preamplifiers
The buffer amplifiers are used for each lead. The “Leads off” detection is implemented by
measuring the output level of the input buffer amplifiers with the A/D converter of the CPU. The
ECG signals are measured using differential amplifiers.
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Module Frames and Modules
ECG amplifiers and baseline restoration
The function of the ECG amplifiers and baseline restoration is to amplify the signal and to
restore the baseline of the signal in the middle of the display after the change of the signal
level, e.g. after the change of the DC offset voltage.
Pacer detection
Pacer detection has been made by using four slew rate detector circuits. The pacer detection
amplifiers have been realized at the front of the slew rate detectors independently of the ECG
measuring channels.
Respiration impedance supply
The 31.25 kHz sine wave generator is used as the respiration measurement signal supply.
Analog switches are used for connecting the sine wave to the ECG leads to be measured.
Respiration impedance amplifiers
Buffer amplifiers are used in respiration measurement. Analog switches are used for selecting
the measurement leads. There are also additional amplifiers for increasing the respiration
signal gain. When ECG measurement is 5/12-lead5/12-lead, the respiration measurement is
always done between R and F, independently on the ECG lead selection. When ECG
measurement is 3-lead, then the respiration measurement is happened at the same lead as
the ECG measurement (I, II, or III).
ECG CPU
The CPU is a 16 bit H8/3052 single-chip microcomputer. It contains 128 kbytes of flash memory
and 4 kbytes of RAM. The clock frequency is 16 MHz.
RS485 communication
The communication to the CPU board of the monitor uses RS485 protocol. The RS485 driver
circuits are optically isolated from the processor of the module.
Power supply
The ECG board has a driver-controlled half-bridge switching power supply with 5 kV isolation.
The supply voltages have been regulated with linear regulators.
ECG filtering
There are three ECG filtering modes:
MONITORING 0.5 to 30 Hz (with 50 Hz reject filter)
0.5 to 40 Hz (with 60 Hz reject filter)
DIAGNOSTIC 12-lead ECG 0.05 to 150 Hz
ST FILTER 0.05 to 30 Hz (with 50 Hz reject filter)
0.05 to 40 Hz (with 60 Hz reject filter)
The purpose of filtering is to reduce high frequency noise and low frequency (e.g. respiratory)
movement artifacts.
The monitor filter is used in normal monitoring. The diagnostic filter is used if more accurate
diagnostic information is needed. The ST filter gives more accurate information of ST segment,
but reduces high frequency noise.
The high-pass filters 0.5 Hz and 0.05 Hz are done with software. The monitor sends a command
to the hemodynamic module determining which of the corner frequencies 0.5 Hz or 0.05 Hz is
to be used.
The 50 Hz and 60 Hz reject filters are both low-pass filters with zero at 50 Hz or 60 Hz
correspondingly. They are software based filters used for the mains supply filtering. With these
filters the 3 dB value for low-pass filter is 30 Hz or 40 Hz.
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In diagnostic mode the upper frequency is 150 Hz and it is limited by software.
1.3.4 STP board
Hemodynamic Modules E-PRESTN, E-RESTN, E-PRETN, E-PSMP, E-PSM
Figure 7 STP board block diagram
Microprocessor unit
The CPU is a 16 bit H8/3052 single-chip microcomputer. It contains 128 kbytes of flash memory
and 4 kbytes of RAM. The clock frequency is 16 MHz.
High speed I/O is used to obtain a pulse control sequence necessary for pulse oximetry
measurement. Timing for the clock is from the oscillator.
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Module Frames and Modules
Temperature measurement unit
The NTC-resistor value in the probe depends on the patient’s temperature. It is measured with
the following principle.
The constant current source supplies about 38 μA current through the temperature sensor
(400 series NTC resistor). The constant current causes a voltage over the temperature sensor
(NTC resistor). The voltage over the temperature sensor is amplified in a differential amplifier
stage. The amplified voltage is transferred to a controller of the STP board through an A/D
converter.
Figure 8 Temperature measurement principle
Invasive blood pressure measurement unit
An isolated +5 V voltage is supplied to the pressure transducer. The differential voltage, which
depends on the pressure and the supplied voltage, is calculated from the bridge connection
(see the formula below).
U
= Uin × pressure × 5 μV, where Uin is 5 V
out
= 25 μV × pressure [mmHg]
U
out
Pressure amplification is realized in the instrumentation amplifier. The gain of the amplifier is
set to keep the level of the signal transferred to the A/D converter within the measurement
range even when there are circumstantial offsets or offsets caused by the transducer. There is
a filter before the amplifier to attenuate high frequency disturbances.
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Hemodynamic Modules E-PRESTN, E-RESTN, E-PRETN, E-PSMP, E-PSM
Figure 9 Pressure measurement principle
Pulse oximetry measurement section
LED control signals
The D/A converters of the microcontroller on the STP board set the LED intensity adjustment
values for the infrared and red LEDs of the SpO
switches the SpO
predetermined sequence.
probe LEDs ON (to the adjusted intensity) and OFF according to the
2
probe. The microcontroller on the STP board
2
LED driving circuit
Differential amplifiers measure the LED currents (LED current indication) of the SpO2 probe over
the shunt resistors placed in the LED current paths. The LED driving voltages (LED voltage
indication) are measured from the driver circuitry. The LED driving circuits also have MOSFET
transistor matrix to enable the use of different probe configurations.
Measured signal preamplification
The preamplifier is a bipolar/single-ended current-to-voltage converter with adjustable gain. A
higher gain is used for measuring thin tissue. The preamplification stage has also ambient light
reduction and a second amplifier stage.
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Module Frames and Modules
Figure 10 Pulse oximetry measurement block diagram
Red and infrared channel separation
It is possible to multiplex the detector signal to four different channels depending on the
content of the signal. The detector signal must at least multiplex into infrared and red signals.
Other channels are e.g. for diagnostic purposes.
Serial communication
An RS485 type bus driver makes the serial communication between the module and the frame.
The data transmission rate is 500kbps.
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Hemodynamic Modules E-PRESTN, E-RESTN, E-PRETN, E-PSMP, E-PSM
Figure 11 Serial communication of E-PSM(P) and E-(P)RE(S)TN module
Signals and isolation barrier
The communication signals transfer over the isolation barrier by using high isolation voltage
(6kV) opto isolators.
Power supply section
The power for the electronics on the floating part of the STP and the ECG boards is made on
each board with the switching power supplies connected to a high voltage isolated
transformer. The switching power supplies on the STP and ECG boards are synchronized to the
frequency, about 340kHz of the switching power supply on the NIBP board. The NIBP board
supplies non-isolated 5 V to the ECG and STP boards. The module uses only Vmod 13.8 - 16 V
voltage of the frame. The other voltages of the measuring boards are made by the switching
power supplies and regulators or the linear regulators. Each measuring board is protected
against overloading with PTC type automatic fuses.
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Module Frames and Modules
1.3.5 NIBP board
Figure 12 NIBP board functional block diagram
Signal processing
Two signals from the pressure transducers are amplified and sent to the A/D converter. After
the converter, digitized signals are sent to the microprocessor for data processing.
The NIBP board is controlled with an H8/3052 microprocessor at 16 MHz oscillator frequency.
Memory
The NIBP program memory (processor flash memory) size is 512k x 8. The processor has 4
kBytes RAM and there is also an external RAM memory, the size of which is 128k x 8. Variable
values of the NIBP measurement are stored into the external RAM. The EEPROM size is 512 x 8
and it is used to store the calibration values for the pressure transducers, the pulse valve
constants gained during measurements, the PC board identification, and the module serial
number.
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