- Email: [email protected]
Comprehensive fetal monitoring by microcomputer—A clinical approach
OOIO-4825/84 s300+ .oo 0 1984 Pergamon Press Ltd.
COMPREHENSIVE FETAL MONITORING BY MICROCOMPUTER-A CLINICAL APPROACH M. Y. DIVON, Z. SARNA,* A. VILENSKY,* E. Z. Z~MMEB, B. A. PERETZ and E. PALDI Department of Obstetrics and Gynecology “B” and *Biomedical Engineering Department, Rambam Medical Center, Haifa, Israel (Received 25 Jarmary 1983; receivedfor publication 14 June 1983)
Abstract-An inexpensive microcomputer has been devised to analyze fetal heart signals and fetal activity which were simultaneously recorded. Digital techniques were used to provide quantitative analysis of each of these inputs, and the interrelations among them. A parallel graphical presentation of those inputs was also provided. Computerized fetal monitoring Fetal beat to beat variability
Fetal movements
Fetal breathing
Fetal heart rate
INTRODUCTION
The advent of electronic fetal monitoring has radically influenced the practice of obstetrics during the last decade. Routine antenatal and intrapartum monitoring has significantly increased the amount of information which affects the clinical management of both mother and fetus. Monitoring of fetal biophysical parameters such as heart rate and body movements [l], are widely accepted methods for evaluation of fetal well being. The subjective visual interpretation of monitored data should be complemented by objective computer quantitation free from human error. Such errors result mainly from limitations imposed by the nature of visual assessment, and by varying expertise of the physician. If the information obtained when evaluating fetal biophysical parameters could be reliably quantitated by a computer, then data stored, analyzed, and averaged would create an objective basis for discriminating the healthy from the compromized fetus. This paper describes a computerized system for simultaneous monitoring of four biophysical parameters which are usually accepted as single indicators of fetal well being. Namely, fetal heart rate-FHR [2], beat to beat variability-BTBV [3], fetal body movements-FBoM. [4], and fetal breathing movements-FBrM [5]. The design of this system was guided by four principles. 1. To provide a means for objective and quantitative analysis of the data. 2. To characterize each of the inputs and the temporal relations among them. 3. The desire to create a simple inexpensive versatile system which would allow for new applications as they arise. 4. To offer the physician the ability to display, transmit and permanently record tracings of fetal biophysical parameters.
MATERIALS
AND
METHODS
Fetal heart signals were obtained either directly via a fetal scalp electrode (after rupture of membranes), or indirectly via abdominal E.C.G. These signals were amplified (using the HP803&A fetal monitor), and then recorded on an F.M. instrumentation taperecorder (TEAC R-60). Fetal body and breathing movements were monitored using a real time ultrasound scanner (A.D.R. Model 2130) the transducer operated at 3.5 MHz, with an average intensity of 0.045 mW/cm2. The transducer was placed on the maternal abdomen and a view obtained 151
M. Y. DILO\, et al
152
I
MICROPNONE
Fig. 1. Recording
of fetal activxty and E.C.G.
of a transverse section of the upper fetal abdomen. Two switches were operated by the observer, one was actuated for every breathing movement, while the other was actuated throughout each fetal body movement. Digital pulses were generated and recorded on separate channels of the tape recorder, corresponding to any such movement detected by the observer (See Fig. 1). On replay the information was fed into a Compucolor II microcomputer (internal memory of 32&L),through a digitizer whose sampling interval was 1 ms (See Fig. 2). Fetal interbeat intervals were first measured by the computer and then put through an error detecting system which recognized invalid heart periods if they were outside the range of 65 to 175% of the average of the last two valid periods. If an erroneous pulse was found, the two adjacent interbeat intervals were also rejected. The total rejection time was measured. Our general processing procedure first involved a graphical synchronized display of four parameters: Fetal Breathing Movements, Fetal Body Movements, Fetal Heart Rate, and Instantaneous Beat-To-Beat Variability (see Fig. 3). Following this, a computerized analysis was performed on each of the inputs, and on the temporal relations among them.
AND
REPLAY
ANALYSIS
PULSE FHR
>
GENERATOR
BODY TAPE RECORDER
MOV.
-
’
(OUTPUT:
BREATH
MOV,
+
>
FM
COMPUTER
SAMPLING
(32K)
INTERFACE
COMPUTER COMPATIBLE PULSES
>
4
1
SAMPLING
RATE
=
1 MSEC.
Fig. 2. Replay
and analysis
of fetal biophysical
parameters.
Comprehensive
fetal monitoring
-. J.,
._
.1
.
153
by microcomputer
‘. ._.’
_:,
.-.
,_.
.’ I’.
._ i
Fig, 3. Synchronized
Fetal heart
presentation
offour fetal biophysical rate, body and breathing
rate was defined
from the interbeat
parameters: movements.
beat-to-beat
_,.:
‘..‘.
variability.
i
heart
intervals T, - T,,-1,
where T, = the nth T, + Tc,mi, interbeat interval (in ms). The fetus was defined as breathing, when the respiratory rate was 10 per minute or more. A gap of more than 6s was defined as cessation of respiration (“Apnea”). The numerical analysis section was programmed to yield the following items: Instantaneous
beat-to-beat
I. Fetal Breathing
variability
Movements
II. Fetal Body Movements
III
Fetal Heart
Rate:
IV
Beat to Beat Variability: Defined as the S.D. of
:
:
was defined
as
Ia. Number of breathing periods. Ib. Percentage of time during which the fetus was breathing. IIa. Number of body movements. IIb. Percentage of time during which the fetus was moving. IIIa. Mean during breathing movements. IIIb. Mean during body movements. 111~. Mean during fetal inactivity periods.
Tn - To-l, during the T, + Tc,-1, following
periods :
IVa.
Fetal breathing
movements.
M. Y. DIVON, et al.
154
.;-..;.,__-, : : .;
.
_.
/
.+..
,.
.I
‘,
..._ ..
1 :
:
. . ..-.....
‘_,
.
.,
.-
Fig. 4. A fetal body movement
along
with the associated
cardiac
activity.
IVb. Fetal body movements. WC. Fetal inactivity periods. Most of the software is written in BASIC with a small segment of 8080 machine program listing is available on request from Z. Sarna.
language.
The
RESULTS Graphical output Figure 4 is a typical illustration of a fetal body movement along with the corresponding fetal heart rate and beat-to-beat variability. Fetal body movements are usually accompanied by a short period of tachycardia. During this period a reduction of beat-to-beat variability and absence of breathing movements are also typical. Figure 5 is a typical illustration of breathing movements along with the corresponding fetal heart rate and beat-to-beat variability. Fetal breathing movements are typically associated with an increase in beat-to-beat variability, while the change in fetal heart rate is relatively small. Numerical analysis Figure 6 shows the different biophysical parameters as they appear in a numerical analysis form. An objective analysis of the inputs and the temporal relations among them is provided. DISCUSSION Several attempts have been made to set up precise rules for the interpretation of fetal heart rate patterns, and to relate these patterns to fetal condition. Chik et al. [6], and Ray et al. [7]
Comprehensive
fetal monitoring
by microcomputer
155
breathing
.
ltlOV.
Fig. 5. Fetal breathing
movements
along
with the associated
cardiac
activity.
developed computer programs able to determine the deceleration patterns seen in fetal heart rate. In 1981 Kariniemi et al. [S] reported the use of microcomputer for evaluation of fetal beat-to-beat variability, and showed its clinical significance. Computerized antepartum evaluation of fetal activity was reported by Bottoms et al. (9). Our study reports a specific microcomputer application that may be useful in perinatal research. Recent investigations in our laboratory [lo] and those of others [ll], indicate that evaluation of fetal biophysical parameters, are a potentially more specific means of identifying the compromized fetus, than conventional techniques based on monitoring fetal heart rate patterns. Fetal biophysical parameters such as body movements, breathing movements, heart rate and beat-to-beat variability, have been accepted as single indicators of fetal well being. Our system provides a separate analysis of each of these inputs, and also a combined analysis which determines the interrelations among them. A portable microcomputer with a variety of peripherals and the ability to hand-wire special applications, was chosen for the current project. The programming language was BASIC. This design allows the creation and testing of new applications as they arise. Using portions of the system we were able to demonstrate the effects of maternal exposure to music on fetal activity [ 121. And the effects of maternal administration of glucose on fetal heart rate patterns [ 131. Results are provided both graphically and numerically. The graphical presentation facilitates visual interpretation of the simultaneously projected data. The increase in both scales as compared with conventional fetal heart rate records, makes it easier to observe the pattern of fetal heart rate and beat to beat variability in relation to fetal activity. The numerical analysis provides objective and quantitative results which cannot be otherwise
M. Y. Di\ou.
156 ‘--===
SYWHRONIZFD ____________
1)BREAtHING _________
et al.
FETAL. ilUYIT@RlNLi _____ ._._______
::=
--
FlOVEl'lENTS _________
NO, OF BREATHING TOTAL BREATHING
F'EF'IODS~,........~..,. e ACTI~ITY,..‘.,,.,,..,.~
127,358 (SEC; 10.h132 %
2)BODY IlOVEtlENTS ____ _________ NO. OF BODY flOVEllENT~ Lt*t.l+.tt*tl**tt, TOTAL DURATION
10
OF BODY i'lOVEllENTS,+.,,..72,936 (SEC) 6.078 %
3)TOTAL FETAL ACTIVITY _____ _-_.- ______._ TOTAL BREATHKNL; AND BODY I'IOVENENTS..... 200,254 !SECI 16.6912 % 4)FETAL HEART RATE _____ _-_-- ---IIEAN F,H.R,...~,.,,~,~......,.......,.. IlEAN
F.H.R. DURING
BEAN F.H.R.
DURING
I'IEANF.H.P. DURING
145.023
!BPm'
144,615
(BPII)
BODY IIOVEIIENTS...... 152,366
(BPII)
NO FETAL ACTIVITY...
(BPR!
BREATINC
ACTIVITY,,.
144.552
5)BEAT TO BEAT VARIABILITY ---- -- ____ ___________
Fig.
6. Numerical
TOTAL.,..,......,.........,..,.,..,,,..
2.65924
DURING BREATHING
ACTIVTTY..,,.,,,...,.,
4.06che
DURING BODY VOVERENTS,,,,.,.,.,,,,..,..
3.04159
DURING NO FETAL ACTIVITY,,,,,,,,,,,.,,,
2,59666
analysis
showing
the
temporal relations parameters.
among
the different
biophysical
obtained. Also it simplifies the comparison between different tracings, and provides a means of condensing large amounts of data which result from continuous monitoring of the fetus. Our study illustrates the practical advantages of the microcomputer in some perinatal data analysis applications. Recently we demonstrated that a statistically significant association exists between fetal activity and fetal heart signals [14]. Fetal body movements were associated with an increased fetal heart rate, and a decreased beat to beat variability, while fetal breathing was associated with increased beat to beat variability. Therefore we suggest that a combined, rather than a separate analysis of the variables included in the “Biophysical Profile”, should be carried out whenever fetal health is assessed. A computerized approach for this analysis is relatively simple, yet it provides a tool which easily quantifies phenomena that can hardly be characterized by visual inspection of conventional tracings. SUMMARY Our study reports a specific microcomputer application that may be useful in perinatal research. Monitoring of fetal biophysical parameters such as: heart rate, beat-to-beat variability, body movements, and breathing movements, is widely accepted for determination of fetal well-being. Each of these parameters is singly accepted as an indicator of fetal health. In this paper we present a computerized system which provides synchronous analysis of those parameters. Thus we can analyze each of these variables separately, and then look into
Comprehensive
fetal monitoring
by microcomputer
157
the interrelations among them. This simple and inexpensive system provides a means for objective and quantitative analysis of the data. Also, it offers the physician the ability to display, transmit and permanently record, tracings of fetal biophysical parameters.
REFERENCES 1. R. G. Goodlin, History of fetal monitoring. Am. J. Obstet. Gynecol. 133, 323 (1979). 2. L. R. Everston, R. J. Gauthier, B. S. Schifrin and R. H. Paul, Antepartum fetal heart rate testing. Evolution of the non stress test. Am. J. Obstet. Gynecol. 133, 29 (1979). 3. N. H. Lauersen, K. H. Wilson, A. Bilek, V. P. J. Rao and M. Kurkulos, A new modality in non stress testing: Evaluation of beat to beat fetal heart rate variability. Am. J. Obstet. Gynecol. 141, 521 (1981). 4. E. Sadovsky, H. Yaffe and W. Polishuk. Fetal movement monitoring in normal and pathological pregnancy. Inc. J. Gyrlecol. Obstet. 12, 75 (1974). 5. L. D. Platt, F. A. Manning and M. Lemay, Human fetal breathing-relationship to fetal condition. Am. J. Obstet. Gqwecol. 32, 514 (1978). 6. L. Chik, M. G. Rosen, V. J. Hirsch and R. J. Sokol, Programmed identification of fetal heart rate deceleration patterns. Am. J. Obstet. Gynecol. 119, 816 (1974). I. H. R. Rey, L. S. James and R. Van der Wiele, Opitimized search for parameters useful in the interpretations of fetal heart rate data. Med. Instrum. 13, 337 (1979). 8. V. Kariniemi and P. Ammala, Short term variability of fetal heart rate during pregnancies with normal and insufficient placental function. Am. J. Obstet. GynecoL 139, 33 (1981). 9. S. F. Bottoms. Y. Sorokin, L. Dierker and M. G. Rosen, Microcomputer analysis of fetal activity patterns using the runs test. In Procx!eding.\of the 2nd Intrrnnrionul Symposium on Computers in Perinutal Medicine, p. 141, R. J. Sokol. Ed. Cleveland, Ohio (1987). 10. M. Y. Divan. E. Z. Zimmer. A. Vilensky, Z. Sarna. B. A. Peretz and E. Paldi, Synchronized monitoring of fetal heart rate and fetal activity. In Procerdings $un Update in High Risk Obstetrics, Tel Aviv, Israel, p. 75 (1981). 11. F. A. Manning, T. F. Baskett, L. Morrison and L. Lange, Fetal biophysical profile scoring: A prospective study in 1,184 high risk patients. Am. J. Obstet. Gynecol. 140, 289 (1981). 12. E. Z. Zimmer, M. Y. Divon. A. Vilensky, Z. Sarna, B. A. Peretz and E. Paldi, Maternal exposure to music and fetal activity. Eur. J. obster. Gpnecol. reprod. Biol. 13, 209 (1982). 13. M. Y. Divon, E. 2. Zimmer, A. Vilensky, Z. Sarna, B. A. Peretz and E. Paldi, Changes in fetal heart rate associated with fetal activity before and after glucose administration. In Proceedings of the 8th International Symposium on Ferul Breuthing und Other Meusurements, de Haan. Ed., p. 29. Maastricht, Holland (1981). 14. M. Y. Divon, Z. Sarna. A. Vilensky, E. Z. Zimmer, B. A. Peretz and E. Paldi, A comprehensive computerized fetal monitoring system. In Proceedings qfthe 2nd Internutionul Symposium on Computers in Perinutal Medicine, p. 47, R. J. Sokol, Ed. Cleveland. Ohio (1982).
About the Author--MI(.HAtL
Y. DIXON, B.Sc.E.E. (1973). M.D. (1979). At present Dr Divon is a resident in the Obstetrics and Gynecology Department at the Rambam Medical Center, Haifa, Israel. His main interest is in Perinatology. IV S,\UI\;.\ received his B.Sc. in physics in 1973 and his MSc. in bio-medical engineering in 1978, both from the Technion-Israel Institute of Technology. Currently he is working with the Biomedical Department at the Rambam Medical Center, Haifa, Israel.
About the Author--Z1
R VIL~NSL~ received his BSc. and M.Sc. in Electrical Engineering and his D.Sc. from the Technion-Israel Institute of Technology. Dr Vilensky is the head of the BioMedical Engineering Department at the Rambam Medical Center, Haifa, Israel.
About the Author--At.rk,~iwi
Z. ZIMMFK received the M.D. degree in 1972 at the Hadassah Medical School, Jerusalem, Israel. From 1978 to 1979 he was a research fellow to Prof. S. Campbell in the Ultrasound Unit at King’s College Hospital, London, England. Since 1980 he has been head of the High Risk Pregnancy clinic at the Rambam Medical Center, Haifa, Israel.
About the Author-ELAN
~AL~L. AL-IL Ptxl~7 received the M.D. degree in 1966 at Base1 University, Switzerland. He is Deputy Head of the Obstetrics and Gynecology “B” Department at the Rambam Medical Center, since 1973. Since 1979 he has been Senior Lecturer. Technion. Facultv of Medicine. Haifa. His main fields of research are infertility-microsurgical repair. Fallopian tube;ltrastructure and fetal monitoring.
About the Author--Bt
About the Author ~ EITAI\; PAI.DI. M.D., graduated
from the Hebrew University Medical School in 1952. Since then has been on the staff of the Obstetric and Gynecology “B” Department at Rambam Medical Center. Ten years ago he was appointed to the Medical School of the Technion, first as Senior Lecturer and for the last five years as Associate Professor of Obstetric Gynecology.
COMPREHENSIVE FETAL MONITORING BY MICROCOMPUTER-A CLINICAL APPROACH M. Y. DIVON, Z. SARNA,* A. VILENSKY,* E. Z. Z~MMEB, B. A. PERETZ and E. PALDI Department of Obstetrics and Gynecology “B” and *Biomedical Engineering Department, Rambam Medical Center, Haifa, Israel (Received 25 Jarmary 1983; receivedfor publication 14 June 1983)
Abstract-An inexpensive microcomputer has been devised to analyze fetal heart signals and fetal activity which were simultaneously recorded. Digital techniques were used to provide quantitative analysis of each of these inputs, and the interrelations among them. A parallel graphical presentation of those inputs was also provided. Computerized fetal monitoring Fetal beat to beat variability
Fetal movements
Fetal breathing
Fetal heart rate
INTRODUCTION
The advent of electronic fetal monitoring has radically influenced the practice of obstetrics during the last decade. Routine antenatal and intrapartum monitoring has significantly increased the amount of information which affects the clinical management of both mother and fetus. Monitoring of fetal biophysical parameters such as heart rate and body movements [l], are widely accepted methods for evaluation of fetal well being. The subjective visual interpretation of monitored data should be complemented by objective computer quantitation free from human error. Such errors result mainly from limitations imposed by the nature of visual assessment, and by varying expertise of the physician. If the information obtained when evaluating fetal biophysical parameters could be reliably quantitated by a computer, then data stored, analyzed, and averaged would create an objective basis for discriminating the healthy from the compromized fetus. This paper describes a computerized system for simultaneous monitoring of four biophysical parameters which are usually accepted as single indicators of fetal well being. Namely, fetal heart rate-FHR [2], beat to beat variability-BTBV [3], fetal body movements-FBoM. [4], and fetal breathing movements-FBrM [5]. The design of this system was guided by four principles. 1. To provide a means for objective and quantitative analysis of the data. 2. To characterize each of the inputs and the temporal relations among them. 3. The desire to create a simple inexpensive versatile system which would allow for new applications as they arise. 4. To offer the physician the ability to display, transmit and permanently record tracings of fetal biophysical parameters.
MATERIALS
AND
METHODS
Fetal heart signals were obtained either directly via a fetal scalp electrode (after rupture of membranes), or indirectly via abdominal E.C.G. These signals were amplified (using the HP803&A fetal monitor), and then recorded on an F.M. instrumentation taperecorder (TEAC R-60). Fetal body and breathing movements were monitored using a real time ultrasound scanner (A.D.R. Model 2130) the transducer operated at 3.5 MHz, with an average intensity of 0.045 mW/cm2. The transducer was placed on the maternal abdomen and a view obtained 151
M. Y. DILO\, et al
152
I
MICROPNONE
Fig. 1. Recording
of fetal activxty and E.C.G.
of a transverse section of the upper fetal abdomen. Two switches were operated by the observer, one was actuated for every breathing movement, while the other was actuated throughout each fetal body movement. Digital pulses were generated and recorded on separate channels of the tape recorder, corresponding to any such movement detected by the observer (See Fig. 1). On replay the information was fed into a Compucolor II microcomputer (internal memory of 32&L),through a digitizer whose sampling interval was 1 ms (See Fig. 2). Fetal interbeat intervals were first measured by the computer and then put through an error detecting system which recognized invalid heart periods if they were outside the range of 65 to 175% of the average of the last two valid periods. If an erroneous pulse was found, the two adjacent interbeat intervals were also rejected. The total rejection time was measured. Our general processing procedure first involved a graphical synchronized display of four parameters: Fetal Breathing Movements, Fetal Body Movements, Fetal Heart Rate, and Instantaneous Beat-To-Beat Variability (see Fig. 3). Following this, a computerized analysis was performed on each of the inputs, and on the temporal relations among them.
AND
REPLAY
ANALYSIS
PULSE FHR
>
GENERATOR
BODY TAPE RECORDER
MOV.
-
’
(OUTPUT:
BREATH
MOV,
+
>
FM
COMPUTER
SAMPLING
(32K)
INTERFACE
COMPUTER COMPATIBLE PULSES
>
4
1
SAMPLING
RATE
=
1 MSEC.
Fig. 2. Replay
and analysis
of fetal biophysical
parameters.
Comprehensive
fetal monitoring
-. J.,
._
.1
.
153
by microcomputer
‘. ._.’
_:,
.-.
,_.
.’ I’.
._ i
Fig, 3. Synchronized
Fetal heart
presentation
offour fetal biophysical rate, body and breathing
rate was defined
from the interbeat
parameters: movements.
beat-to-beat
_,.:
‘..‘.
variability.
i
heart
intervals T, - T,,-1,
where T, = the nth T, + Tc,mi, interbeat interval (in ms). The fetus was defined as breathing, when the respiratory rate was 10 per minute or more. A gap of more than 6s was defined as cessation of respiration (“Apnea”). The numerical analysis section was programmed to yield the following items: Instantaneous
beat-to-beat
I. Fetal Breathing
variability
Movements
II. Fetal Body Movements
III
Fetal Heart
Rate:
IV
Beat to Beat Variability: Defined as the S.D. of
:
:
was defined
as
Ia. Number of breathing periods. Ib. Percentage of time during which the fetus was breathing. IIa. Number of body movements. IIb. Percentage of time during which the fetus was moving. IIIa. Mean during breathing movements. IIIb. Mean during body movements. 111~. Mean during fetal inactivity periods.
Tn - To-l, during the T, + Tc,-1, following
periods :
IVa.
Fetal breathing
movements.
M. Y. DIVON, et al.
154
.;-..;.,__-, : : .;
.
_.
/
.+..
,.
.I
‘,
..._ ..
1 :
:
. . ..-.....
‘_,
.
.,
.-
Fig. 4. A fetal body movement
along
with the associated
cardiac
activity.
IVb. Fetal body movements. WC. Fetal inactivity periods. Most of the software is written in BASIC with a small segment of 8080 machine program listing is available on request from Z. Sarna.
language.
The
RESULTS Graphical output Figure 4 is a typical illustration of a fetal body movement along with the corresponding fetal heart rate and beat-to-beat variability. Fetal body movements are usually accompanied by a short period of tachycardia. During this period a reduction of beat-to-beat variability and absence of breathing movements are also typical. Figure 5 is a typical illustration of breathing movements along with the corresponding fetal heart rate and beat-to-beat variability. Fetal breathing movements are typically associated with an increase in beat-to-beat variability, while the change in fetal heart rate is relatively small. Numerical analysis Figure 6 shows the different biophysical parameters as they appear in a numerical analysis form. An objective analysis of the inputs and the temporal relations among them is provided. DISCUSSION Several attempts have been made to set up precise rules for the interpretation of fetal heart rate patterns, and to relate these patterns to fetal condition. Chik et al. [6], and Ray et al. [7]
Comprehensive
fetal monitoring
by microcomputer
155
breathing
.
ltlOV.
Fig. 5. Fetal breathing
movements
along
with the associated
cardiac
activity.
developed computer programs able to determine the deceleration patterns seen in fetal heart rate. In 1981 Kariniemi et al. [S] reported the use of microcomputer for evaluation of fetal beat-to-beat variability, and showed its clinical significance. Computerized antepartum evaluation of fetal activity was reported by Bottoms et al. (9). Our study reports a specific microcomputer application that may be useful in perinatal research. Recent investigations in our laboratory [lo] and those of others [ll], indicate that evaluation of fetal biophysical parameters, are a potentially more specific means of identifying the compromized fetus, than conventional techniques based on monitoring fetal heart rate patterns. Fetal biophysical parameters such as body movements, breathing movements, heart rate and beat-to-beat variability, have been accepted as single indicators of fetal well being. Our system provides a separate analysis of each of these inputs, and also a combined analysis which determines the interrelations among them. A portable microcomputer with a variety of peripherals and the ability to hand-wire special applications, was chosen for the current project. The programming language was BASIC. This design allows the creation and testing of new applications as they arise. Using portions of the system we were able to demonstrate the effects of maternal exposure to music on fetal activity [ 121. And the effects of maternal administration of glucose on fetal heart rate patterns [ 131. Results are provided both graphically and numerically. The graphical presentation facilitates visual interpretation of the simultaneously projected data. The increase in both scales as compared with conventional fetal heart rate records, makes it easier to observe the pattern of fetal heart rate and beat to beat variability in relation to fetal activity. The numerical analysis provides objective and quantitative results which cannot be otherwise
M. Y. Di\ou.
156 ‘--===
SYWHRONIZFD ____________
1)BREAtHING _________
et al.
FETAL. ilUYIT@RlNLi _____ ._._______
::=
--
FlOVEl'lENTS _________
NO, OF BREATHING TOTAL BREATHING
F'EF'IODS~,........~..,. e ACTI~ITY,..‘.,,.,,..,.~
127,358 (SEC; 10.h132 %
2)BODY IlOVEtlENTS ____ _________ NO. OF BODY flOVEllENT~ Lt*t.l+.tt*tl**tt, TOTAL DURATION
10
OF BODY i'lOVEllENTS,+.,,..72,936 (SEC) 6.078 %
3)TOTAL FETAL ACTIVITY _____ _-_.- ______._ TOTAL BREATHKNL; AND BODY I'IOVENENTS..... 200,254 !SECI 16.6912 % 4)FETAL HEART RATE _____ _-_-- ---IIEAN F,H.R,...~,.,,~,~......,.......,.. IlEAN
F.H.R. DURING
BEAN F.H.R.
DURING
I'IEANF.H.P. DURING
145.023
!BPm'
144,615
(BPII)
BODY IIOVEIIENTS...... 152,366
(BPII)
NO FETAL ACTIVITY...
(BPR!
BREATINC
ACTIVITY,,.
144.552
5)BEAT TO BEAT VARIABILITY ---- -- ____ ___________
Fig.
6. Numerical
TOTAL.,..,......,.........,..,.,..,,,..
2.65924
DURING BREATHING
ACTIVTTY..,,.,,,...,.,
4.06che
DURING BODY VOVERENTS,,,,.,.,.,,,,..,..
3.04159
DURING NO FETAL ACTIVITY,,,,,,,,,,,.,,,
2,59666
analysis
showing
the
temporal relations parameters.
among
the different
biophysical
obtained. Also it simplifies the comparison between different tracings, and provides a means of condensing large amounts of data which result from continuous monitoring of the fetus. Our study illustrates the practical advantages of the microcomputer in some perinatal data analysis applications. Recently we demonstrated that a statistically significant association exists between fetal activity and fetal heart signals [14]. Fetal body movements were associated with an increased fetal heart rate, and a decreased beat to beat variability, while fetal breathing was associated with increased beat to beat variability. Therefore we suggest that a combined, rather than a separate analysis of the variables included in the “Biophysical Profile”, should be carried out whenever fetal health is assessed. A computerized approach for this analysis is relatively simple, yet it provides a tool which easily quantifies phenomena that can hardly be characterized by visual inspection of conventional tracings. SUMMARY Our study reports a specific microcomputer application that may be useful in perinatal research. Monitoring of fetal biophysical parameters such as: heart rate, beat-to-beat variability, body movements, and breathing movements, is widely accepted for determination of fetal well-being. Each of these parameters is singly accepted as an indicator of fetal health. In this paper we present a computerized system which provides synchronous analysis of those parameters. Thus we can analyze each of these variables separately, and then look into
Comprehensive
fetal monitoring
by microcomputer
157
the interrelations among them. This simple and inexpensive system provides a means for objective and quantitative analysis of the data. Also, it offers the physician the ability to display, transmit and permanently record, tracings of fetal biophysical parameters.
REFERENCES 1. R. G. Goodlin, History of fetal monitoring. Am. J. Obstet. Gynecol. 133, 323 (1979). 2. L. R. Everston, R. J. Gauthier, B. S. Schifrin and R. H. Paul, Antepartum fetal heart rate testing. Evolution of the non stress test. Am. J. Obstet. Gynecol. 133, 29 (1979). 3. N. H. Lauersen, K. H. Wilson, A. Bilek, V. P. J. Rao and M. Kurkulos, A new modality in non stress testing: Evaluation of beat to beat fetal heart rate variability. Am. J. Obstet. Gynecol. 141, 521 (1981). 4. E. Sadovsky, H. Yaffe and W. Polishuk. Fetal movement monitoring in normal and pathological pregnancy. Inc. J. Gyrlecol. Obstet. 12, 75 (1974). 5. L. D. Platt, F. A. Manning and M. Lemay, Human fetal breathing-relationship to fetal condition. Am. J. Obstet. Gqwecol. 32, 514 (1978). 6. L. Chik, M. G. Rosen, V. J. Hirsch and R. J. Sokol, Programmed identification of fetal heart rate deceleration patterns. Am. J. Obstet. Gynecol. 119, 816 (1974). I. H. R. Rey, L. S. James and R. Van der Wiele, Opitimized search for parameters useful in the interpretations of fetal heart rate data. Med. Instrum. 13, 337 (1979). 8. V. Kariniemi and P. Ammala, Short term variability of fetal heart rate during pregnancies with normal and insufficient placental function. Am. J. Obstet. GynecoL 139, 33 (1981). 9. S. F. Bottoms. Y. Sorokin, L. Dierker and M. G. Rosen, Microcomputer analysis of fetal activity patterns using the runs test. In Procx!eding.\of the 2nd Intrrnnrionul Symposium on Computers in Perinutal Medicine, p. 141, R. J. Sokol. Ed. Cleveland, Ohio (1987). 10. M. Y. Divan. E. Z. Zimmer. A. Vilensky, Z. Sarna. B. A. Peretz and E. Paldi, Synchronized monitoring of fetal heart rate and fetal activity. In Procerdings $un Update in High Risk Obstetrics, Tel Aviv, Israel, p. 75 (1981). 11. F. A. Manning, T. F. Baskett, L. Morrison and L. Lange, Fetal biophysical profile scoring: A prospective study in 1,184 high risk patients. Am. J. Obstet. Gynecol. 140, 289 (1981). 12. E. Z. Zimmer, M. Y. Divon. A. Vilensky, Z. Sarna, B. A. Peretz and E. Paldi, Maternal exposure to music and fetal activity. Eur. J. obster. Gpnecol. reprod. Biol. 13, 209 (1982). 13. M. Y. Divon, E. 2. Zimmer, A. Vilensky, Z. Sarna, B. A. Peretz and E. Paldi, Changes in fetal heart rate associated with fetal activity before and after glucose administration. In Proceedings of the 8th International Symposium on Ferul Breuthing und Other Meusurements, de Haan. Ed., p. 29. Maastricht, Holland (1981). 14. M. Y. Divon, Z. Sarna. A. Vilensky, E. Z. Zimmer, B. A. Peretz and E. Paldi, A comprehensive computerized fetal monitoring system. In Proceedings qfthe 2nd Internutionul Symposium on Computers in Perinutal Medicine, p. 47, R. J. Sokol, Ed. Cleveland. Ohio (1982).
About the Author--MI(.HAtL
Y. DIXON, B.Sc.E.E. (1973). M.D. (1979). At present Dr Divon is a resident in the Obstetrics and Gynecology Department at the Rambam Medical Center, Haifa, Israel. His main interest is in Perinatology. IV S,\UI\;.\ received his B.Sc. in physics in 1973 and his MSc. in bio-medical engineering in 1978, both from the Technion-Israel Institute of Technology. Currently he is working with the Biomedical Department at the Rambam Medical Center, Haifa, Israel.
About the Author--Z1
R VIL~NSL~ received his BSc. and M.Sc. in Electrical Engineering and his D.Sc. from the Technion-Israel Institute of Technology. Dr Vilensky is the head of the BioMedical Engineering Department at the Rambam Medical Center, Haifa, Israel.
About the Author--At.rk,~iwi
Z. ZIMMFK received the M.D. degree in 1972 at the Hadassah Medical School, Jerusalem, Israel. From 1978 to 1979 he was a research fellow to Prof. S. Campbell in the Ultrasound Unit at King’s College Hospital, London, England. Since 1980 he has been head of the High Risk Pregnancy clinic at the Rambam Medical Center, Haifa, Israel.
About the Author-ELAN
~AL~L. AL-IL Ptxl~7 received the M.D. degree in 1966 at Base1 University, Switzerland. He is Deputy Head of the Obstetrics and Gynecology “B” Department at the Rambam Medical Center, since 1973. Since 1979 he has been Senior Lecturer. Technion. Facultv of Medicine. Haifa. His main fields of research are infertility-microsurgical repair. Fallopian tube;ltrastructure and fetal monitoring.
About the Author--Bt
About the Author ~ EITAI\; PAI.DI. M.D., graduated
from the Hebrew University Medical School in 1952. Since then has been on the staff of the Obstetric and Gynecology “B” Department at Rambam Medical Center. Ten years ago he was appointed to the Medical School of the Technion, first as Senior Lecturer and for the last five years as Associate Professor of Obstetric Gynecology.