Only four of the five published randomised controlled trials (RCT) were included in the analysis. The first RCT by Westgate et al. was excluded because the ST Analysis method used in that study was different from the method used in the more recent studies. Individual data from 6524 participants in the CTG+ST Analysis group and 6463 participants in the CTG group were included in the analysis.

The analysis was conducted on intention-to-treat basis and using the random effects model.

The authors comment that their meta-analysis gives a conservative result on the added value of ST Analysis as it did not include the Westgate et al. study which showed a significant decrease in metabolic acidosis. In addition, the analysis included imputation of missing values resulting in an addition of 7 (15%) metabolic acidosis case to the CTG+ST Analysis group and only 6 (9%) cases to the CTG group.

The analysis showed that CTG+ST Analysis lead to a reduction in the frequency of operative vaginal deliveries and fetal blood sampling. The incidence of metabolic acidosis was reduced by 25% but this was not statistically significant. The overall very low incidence of metabolic acidosis (1%) may be the result of better interpretation of CTG thanks to the use of the Stan Guidelines CTG interpretation in all patients and the required training before using ST Analysis.

1. Schuit et al. Effectiveness of electronic fetal monitoring with additional ST-analysis in vertex singleton pregnancies beyond 36 weeks of gestation: an individual participant data meta-analysis. Am J Obstet Gynecol 2013;208:187.e1-13

Abstract – Schuit et al. 2013

The CTG program is in French and has been adapted by an expert group to French CTG guidelines and management recommendations.

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To set up synchronization against a CMS, the following prerequisites must be fulfilled:
A: Your STAN S31 must have software version R6A or later.
B: You must a Central Monitoring System that support clock synchronization. (Check with your CMS vendor for confirmation.)

To set up synchronization against a network server, the following prerequisites must be fulfilled:
A: Your STAN S31 must have software version R4H or later.
B: Your STAN S31 need to be configured for TCP/IP. (See separate instruction.)
C: Within the network there must be a computer or server supporting the NTP/SNTP protocol. Alternatively, if your STAN S31 has access to the internet, an internet server can be used. (Check with your IT department for recommendations.)

Configuring clock synchronization against a CMS server

First make sure your STAN S31 is connected to your CMS. Then start STAN and enter the System Settings dialog by first tapping the Tap to access service functions field during system start up (finish possible ongoing recordings by selecting Start New if asked), and then selecting the Change Settings button.

In the list of settings, highlight TIMESYNC_METHOD and then select Edit Setting. Change the setting to ‘CMS Server’ and select OK.

Exit the System Settings dialog by selecting Exit and then select Set Time. Change the STAN clock using the arrows so that it differs 15 to 20 minutes from the actual time. Select Exit and start a new recording. Ensure that the CMS communication works (green Central Monitoring indicator in the lower left corner of the screen).

Let the recording run for a minute and then end the recording by selecting the End button and then confirm by selecting End Recording. A confirmation dialog should now appear informing that the clock has been synchronized, showing the actual time.

Note that when STAN is configured with CMS clock synchronization, the CMS will send its local time to the STAN monitor. It is therefore not necessary (or possible) to configure STAN to adapt to daylight savings time changes. Also note that the CMS send date and time information with a precision in minutes, meaning that the STAN and CMS clocks may naturally differ up to one half minute.

Configuring clock synchronization against a network server

First make sure your STAN S31 is connected to the network. Start STAN and enter the System Settings dialog by first tapping the Tap to access service functions field during system start up (finish possible ongoing recordings by selecting Start New if asked), and then selecting the Change Settings button.

In the list of settings, highlight ‘TIMESYNC_METHOD’ and then select Edit Setting. Change the setting to ‘SNTP Server’ and select OK.

Highlight the ‘SNTP_SERVER_IP’ setting and then select Edit Setting. Enter an IP address or DNS name for a server or computer that hosts an SNTP server. This can be either within your local intranet, or if your STAN can access the internet, an internet NTP server.

The SNTP service only provides a universal timestamp (UTC). Therefore, for the STAN unit to be able to calculate your local time given this universal timestamp, you also need to configure your time zone in relation to UTC, and how daylight savings time is to be handled.

Highlight the ‘TIMEZONE’ setting and then select Edit Setting. Select a time zone setting corresponding to your location, e.g. ‘GMT +1:00 hours’ for most western European countries, ‘GMT’ for United Kingdom etc.

If your location uses daylight savings time, highlight the ‘DST_RULE’ setting and then select Edit Setting. Select the rule that apply for your location.

Now test your settings by selecting the System Status menu button. The field Network settings in the upper left corner should have an indicator ‘SNTP server’. This indicator should show the current UTC time. If it does not, you should troubleshoot your network connection. You may also want to double-check that you have entered a correct address to the SNTP server, that the SNTP service is supported on this server, and that your STAN system is located on the same subnet as this server.

If a timestamp is displayed, exit the System Status dialog by pressing Done. Then exit the System Settings dialog by selecting Exit. Then enter the Time and Date dialogue by selecting Set Time. Select the Sync Now button to correct your clock. From now on, your STAN system will automatically synchronize the clock. Before you exit, verify that the displayed time is correct, and that the indication for the next daylight savings time change is correct.

Start the STAN and enter the System Settings dialog by first tapping the Tap to access service functions field during system start up (finish possible ongoing recordings by selecting Start New if asked), and then selecting the Change Settings button.

If there is a DHCP server on the network has a DHCP server, change the USE_DHCP setting to Yes. The DHCP server will supply the STAN with an IP address, subnet mask, and possibly also a DNS server and gateway if that is supported on the local network.

If you are not using a DHCP server, ensure the USE_DHCP setting is set to No. Then set the MACHINE_IP to the fixed IP address, and the MACHINE_IP_MASK to an appropriate subnet mask. If you want to use DNS name resolution, also set the DNS_IP. If communication through a gateway is required, e.g. if printers are localised on another subnet, GATEWAY_IP also needs to be set.

Note that the default MACHINE_IP, 127.0.0.1, stands for localhost,  which cannot be used if communicating with other computers or servers on a network.

Select the System Status menu button and verify the settings in  the External Status view of the System Status dialog.

The IP-addresses of network services are displayed in the Network field. After each IP address, the current status for the connection is stated as Offline (meaning that the network is temporarily offline), Online (that the network node could be reached using the ping protocol), or Inaccessible (meaning that the network is online, but there is no reply over the ICMP Echo (i.e. ping) protocol). Wait means that the network is being reconfigured.

If a DHCP server is configured, IP Address in the Network field should display an IP address with four numbers separated by dots. Automatic configuration can take several minutes each time the setting is being changed, depending on the DHCP server.

If a DHCP server is not being used, the connection can be verified by looking at the status of a configured DNS Server, Gateway or page printer if any configured. The status should then say Online. If none of those are configured, try to verify using the ping command from another computer on the network.

Configure STAN for IP networking as described above. If STAN and the printer are to be connected locally using a crossed cable, we recommend that both STAN and printer are configured with fixed IP addresses in the 192.168.0.x series (e.g. 192.168.0.1 for STAN and 192.168.0.2 for the printer), with subnet mask 255.255.255.0. Remember that for this configuration, a CNK 101 003 Ethernet Isolation Box is needed between STAN S31 and the printer.

Set any of the three PAGEPRINTER_X_ COMMTYPE settings to Network Printer.

Then set the corresponding PAGEPRINTER_X_IPADDRESS to the printer’s IP address on the network, or its DNS network name. Note that if a DNS name is used, a DNS server needs to be configured, either automatically through the use of a DHCP server, or manually using the DNS_IP setting. If the printer is not within the same subnet as the STAN, a gateway must be configured, either through a DHCP server of manually using the GATEWAY_IP setting.

If a printer server is used, or if the printer has multiple queues, set the corresponding PAGEPRINTER_X_QUEUENAME to the LPD queuename for the specific printer/queue.

If several printers are configured, it might be a good idea to set the corresponding PAGEPRINTER_X_NAME to something the users can relate to, e.g. Expedition, or Brother. If this is left blank, Printer <x> will be used instead when referring to the printer in the GUI.

Enter the System Status dialog by selecting the System Status button. Select the External Devices view.

Ensure that the printer is reachable by STAN by checking that the status notification in the Printers field states Online. If Inaccessible is stated instead, it means that the printer does not reply to ICMP Echo requests from the STAN unit, and further troubleshooting is needed. Note that a firewall installed on the network between STAN and the printer may block ICMP packets but still allow print jobs to get through. Printing a test page by selecting Test Print gives a definite answer.

Make a test printout, and adjust the corresponding PAGEPRINTER_X_GRAYLEVEL if necessary. The default setting, Normal, is good for most printers. If 143 (147) PRD 101 009/44 R5B February 2010 the users feel that the printout is too dark or too bright, the setting might need to be adjusted.

1. Use a USB stick that works with Stan S31. Note that you cannot use the same USB as you use for archiving Stan recordings.

2. To test whether a USB stick works with Stan, start a new recording, hold down the ‘End’ menu button and then press the ‘System Status’ dialog that appears. Select the ‘External devices’ view. Connect your USB stick to Stan and verify that within a few seconds, the contents of the ‘USB Media’ field changes from ‘Not Connected’ to reflect the contents of the stick you connected. If it does, this means that the USB stick can be used with Stan.

3. Connect the USB to your PC. Copy the Stan.ini-file to the root directory of the USB stick. This file defines the USB stick as a demo disk.

4. Copy your recording files to the USB stick. Please note that you may want to remove patient name and ID from each recording file. If you do not, the name and ID will be visible in the ‘Patient Data’ field of the Stan screen during the demonstration. You can remove patient name and ID using Stan Viewer software file by file using the ‘Send Email’ function. You can also do a batch anonymization by following this instruction.

5. Your demo disk is now ready for use. Connect it to the Stan monitor before turning the power on. During the startup process, Stan S31 will detect the demo disk and ask if you want to run in demo mode. (You need to finish any ongoing recordings if asked.) Select the ‘Playback Demo’ menu button to enter demo mode.

6. In the Demo dialog, three different playback modes can be selected using the three buttons to the left. Two of these modes can be used with your STN/STF files:
• Playback from STN file , which runs the recording ‘live’ from start to finish.
• Browse recording, which brings up an STN recording as if it was finished.
Select demo mode, select the recording, and press the ‘Start’ menu button

7. You can also adapt certain demo mode settings, of which the most relevant is INPUT_FILE_SPEED which controls how fast the playback will be. Set this parameter to ‘1’ if you want to run in real-time speed, ‘2’ if you want the demo to run in twice the real-time speed etc.

When we made the decision to implement ST Analysis, we were very much focused on education and training. Before going live with the method all 160 midwifes and doctors went through theoretical and practical education and became certified Stan users. Right from the start regular sessions for retrospective case discussions have been part of a continuous learning process.

And was the implementation successful?

Yes, very successful. It was worthwhile spending efforts on education already from the start. We believe it reduced the risk of deliveries with adverse outcome due to staff not understanding the methodology or not following the guidelines.

From the start we also created a simple research form, a CRF to register all Stan cases in order to be able to follow-up our performance. We recently published our 5-years results that include over 6,000 high risk cases monitored with ST Analysis.

Over the five years, our usage of ST Analysis increased and was by the end of the study period almost 34 %. The proportion of cord metabolic acidosis cases decreased with 79% over the study period, and at the same time the overall cesarean delivery rate also decreased.

You gave a presentation at the Nordic Congress of Ob/Gyn in June about how you have organised your data collection. Can you tell us about that?

All our Stan monitors are connected to Ethernet, which is the requirement for digital archiving of the recordings. This makes it possible to organise a digital library of Stan recordings for retrospective analysis, education and research. We can find and open any specific recording at any time at any connected hospital computer and look at the file with Stan Viewer software.

For the antepartum observation of high risk patients we use Stan monitors equipped with the STV feature. These recordings are of course stored digitally as well, which simplifies the assessment and signing.

We also use the Stan Viewer Live program, which allows us to look at on-going recordings in real time from any of the hospital computers. When you are called, you can assess the on-going recording from your office within seconds and decide whether to go to the labour ward immediately or not. It has also become easy to discuss on-going recordings with colleagues outside the delivery room. All our staff is very content with these programs which have simplified our work flow considerably.

Fifty external and fifty internal recordings were obtained from spontaneous or instrumental vaginal deliveries continuously monitored for one hour or more prior to delivery during the second half of 2007.

The assessment of the recordings showed that decelerations were the most common observation for both external and internal recordings, found in 71.9% and 89.1% of recordings respectively. Accelerations were observed in 28.1 % of external and 10.9% of internal recordings. In 11.7 % of the external and in 4% of the internal recording with accelerations, these coincided with contractions.

The findings confirm that fetal heart rate accelerations are more common with external than with internal monitoring, but that they occur in both groups. However, it is more likely to inadvertently record a maternal heart rate as fetal when using an external transducer. The likelihood of observing accelerations coinciding with contractions is less than half when a scalp electrode for internal monitoring is used.

The assessment of the recordings also confirmed that the absence of a p-wave in the ECG waveform helps to differentiate the maternal from the fetal heart rate. When recording the fetal ECG using a scalp electrode and skin electrode placed on the mother’s thigh, it is only the fetal ECG signal that has sufficient strength to show the p-wave. If the maternal heart rate, i.e. ECG, is recorded the p-wave will not be visible in the recording.

This illustration is not from Nurani et al. but shows the identification of a p-wave in the fetal ECG recording.

Abstract – Nurani et al. 2012