Fetal Health Surveillance - Chapter 6 PDF

Chapter 6: Lesson (Classification and Instrumentation) Indications for Intrapartum Electronic Fetal Monitoring EFM is a screening tool for use when enhanced monitoring is required based on the presence of perinatal risk factors or abnormal findings on IA. EFM should always be interpreted in contex...

Chapter 6: Lesson (Classification and Instrumentation) Indications for Intrapartum Electronic Fetal Monitoring EFM is a screening tool for use when enhanced monitoring is required based on the presence of perinatal risk factors or abnormal findings on IA. EFM should always be interpreted in context of the total clinical picture. Interpretation of the FHS findings (FHR and UA) and the management plan are dependent on the gestational age, fetal health before labour, the maternal clinical condition, the stage of labour, and available human resources and skills. The SOGC (2020) recommends the use of EFM when perinatal risk factors are present or when there is a potential for adverse perinatal outcome (see Table 6.1). **FUNDAMENTALS OF FETAL HEALTH SURVEILLANCE** ubccpd.ca Indications for Intrapartum Electronic Fetal Monitoring **Table 6.1** +-----------------------+-----------------------+-----------------------+ | | | | +-----------------------+-----------------------+-----------------------+ | | | | +-----------------------+-----------------------+-----------------------+ | | - Hypertensive | - Pre-pregnancy BMI | | | disorders of | greater than | | | pregnancy | 35kg/m2 | | | | | | | - Diabetes: | - Other factors | | | pre-existing and | (smoking, | | | gestational | substance use, | | | | limited prenatal | | | - Medical disease | care) | | | (e.g., cardiac, | | | | significant | - Advanced maternal | | | anemia, | age (AMA) | | | hyperthyroidism, | (greater than 35 | | | vascular and/or | years at time of | | | renal disease) | labour)\* | | | | | | | - Maternal | | | | perception of | | | | reduced or absent | | | | fetal movement | | | | | | | | - Antepartum | | | | hemorrhage | | +-----------------------+-----------------------+-----------------------+ | | - Intrauterine | 3 or more nuchal | | | growth | loops | | | restriction | | | | (IUGR) | | | | | | | | - Abnormal | | | | umbilical artery | | | | doppler | | | | velocimetry | | | | | | | | - Single umbilical | | | | artery | | | | | | | | - Oligohydramnios | | | | | | | | - Polyhydramnios | | | | | | | | - Abnormal BPP or | | | | NST | | | | | | | | - Significant fetal | | | | abnormality | | | | (compatible with | | | | life) | | | | | | | | - Iso-immunization | | | | | | | | - Multiple | | | | pregnancy | | | | | | | | - Velamentous cord | | | | insertion | | +-----------------------+-----------------------+-----------------------+ | | | | +-----------------------+-----------------------+-----------------------+ | | - Vaginal bleeding | | | | in labour | | | | | | | | - Intrauterine | | | | infection/chorioa | | | | mnionitis | | | | | | | | - Previous CS/trial | | | | of labour after | | | | CS | | | | | | | | - Prolonged rupture | | | | of membranes at | | | | term (greater | | | | than 24 hours) | | | | | | | | - Combined | | | | spinal-epidural | | | | analgesia | | | | | | | | - Oxytocin | | | | induction or | | | | augmentation of | | | | labour | | | | | | | | - Post term | | | | pregnancy | | | | (greater than | | | | 42weeks | | | | gestation) | | | | | | | | - Labour dystocia | | | | | | | | - Tachysystole | | | | | | | | - Difficulties in | | | | reliably | | | | determining UA | | | | and/or FHR with | | | | IA | | +-----------------------+-----------------------+-----------------------+ | | - Abnormal FHS (FHR | | | | and UA) via IA | | | | | | | | - Prematurity (less | | | | than 37 weeks | | | | gestation) | | | | | | | | - Meconium staining | | | | of the amniotic | | | | fluid | | | | | | | | - Breech | | | | presentation | | | | | | | | - FHR arrhythmia | | +-----------------------+-----------------------+-----------------------+ | BMI = Body mass | | | | index; BPP = | | | | Biophysical profile; | | | | CS = Cesarean | | | | section; EFM = | | | | Electronic fetal | | | | monitoring; FHR = | | | | Fetal heart rate; IA | | | | = | | | | | | | | Intermittent | | | | auscultation; NST = | | | | Non-stress test; ROM | | | | = Rupture of | | | | membranes; UA = | | | | Uterine activity | | | | | | | | *\*Note: AMA is not | | | | included in the 2020 | | | | SOGC Guideline, but | | | | was included in the | | | | 2020 Advances in | | | | Labour and Risk* | | | +-----------------------+-----------------------+-----------------------+ Adapted from the Society of Obstetricians and Gynecologists of Canada's "No. 396-Fetal Health Surveillance: Intrapartum Consensus Guideline" by Dore & Ehman (2020), Journal of Obstetrics and Gynecology Canada, 42(3), Table 3, p. 325. Copyright 2020. Published by Elsevier Inc. All rights reserved. Admission FHR Assessment: IA or EFM? A 2017 Cochrane review compared the effects of admission EFM tracing and IA on maternal and neonatal outcomes for women without perinatal risk factors (n=1300). Women allocated to admission EFM tracing were: - 20% more likely to have a Cesarean section - More likely to experience continuous EFM and fetal blood sampling during labour - No more likely to experience artificial rupture of membranes, augmentation of labour, use of an epidural, assisted vaginal births or fetal/neonatal morbidity and mortality. These recommendations are supported by a 2018 multicentre randomized trial by Smith et al. that looked at low-risk healthy women who presented with signs of early labour; on arrival to triage, they were randomized to admission assessment with IA or with EFM. Although not applicable to Canadian practice because of different labour management strategies and lower cesarean section rates, the study found no statistical difference in cesarean section rate (8.6 with IA and 6.9% with EFM) but did find a statistically significant increased use of continuous EFM during labour in the EFM group. This supports the Canadian decision to use admission IA when assessing low-risk people who present with signs and symptoms of possible labour.  IA is the recommended fetal surveillance method for assessing the fetus on admission to triage/birthing unit for low-risk pregnancies (i.e. healthy, term 37^0^-41^3^ weeks, absence of risk factors for adverse perinatal outcomes) (SOGC, 2020). Admission EFM tracings are **not** recommended for healthy, term people presenting in labour, early labour or query labour in the absence of risk factor(s). Use of EFM monitoring in the low-risk population may lead to unnecessary interventions with no evident benefits.  Admission EFM tracings are recommended for people with risk factor(s) for adverse perinatal outcomes (see Table 6.1 on previous page). Frequency of EFM Assessments **Table 6.2** +-----------------------+-----------------------+-----------------------+ | **Recommended | | | | frequency of EFM | | | | assessments (UA and | | | | FHR)** | | | | | | | | **when continuous EFM | | | | is indicated during | | | | labour** | | | +=======================+=======================+=======================+ | *NOTE:* | | | | | | | | *Frequency of | | | | assessments, | | | | response, and | | | | documentation should | | | | always be determined | | | | by maternal-fetal | | | | status. Frequency | | | | needs to increase in | | | | the presence of | | | | atypical and abnormal | | | | FHS or other changes* | | | | | | | | *in the | | | | maternal-fetal | | | | condition.* | | | +-----------------------+-----------------------+-----------------------+ | **First stage: Latent | **First stage: Active | **Second stage: | | phase** | phase** | Active phase** | | | | | | | **Second stage: | | | | Passive phase** | | +-----------------------+-----------------------+-----------------------+ | - Initial | - Every 15 minutes | - At least every 15 | | assessment | | minutes if | | | | continuous | | - At least every | | tracing and | | hour if admitted | | caregiver present | | | | continuously | | - Individualized | | | | based on | | | | maternal-fetal | | | | status if needs | | | | to stay in triage | | | | (not admitted) | | | +-----------------------+-----------------------+-----------------------+ | *NOTE: If the tracing | | | | does not meet the | | | | criteria for being | | | | interpretable, | | | | consider more | | | | frequent assessments | | | | or internal | | | | monitoring of the FHR | | | | and/or the UA.* | | | +-----------------------+-----------------------+-----------------------+ | *Adapted from* *Fetal | | | | Health Surveillance: | | | | Intrapartum Consensus | | | | Guideline -- Table | | | | 12. Society of | | | | Obstetricians and | | | | Gynecologist of | | | | Canada (2020). 42(3): | | | | 333.* | | | +-----------------------+-----------------------+-----------------------+ EFM Methods There are different methods to assess UA and the FHR with the electronic fetal monitor. Being aware of the advantages and disadvantages of each method will assist care providers in choosing the most appropriate method for the clinical situation and the patient's comfort. 1\. External/Indirect Monitoring Click on the hotspot over the **Tocodynamomter** and the **Ultrasound Transducer** to learn more about them. **Fetal Heart Rate: Ultrasound Transducer** - Ultrasound signal reflected from a moving structure (fetal heart).  Reflected beam is received by the ultrasound transducer and displayed in frequency of beats per minute. - Placed over the fetal back and held in place on the abdomen with external belts or adhesive strips.   - "Autocorrelation" used to filter out  artifact and produce cleaner, more interpretable tracing. **Uterine Activity: Tocodynamometer Transducer ("Toco")** - An external pressure-sensitive device that detects changes in surface pressure when the uterus contracts and presses against it. - Approximates the UA start and finish but does not measure contraction intensity or resting tone. - Held in place on the abdomen with external belts or adhesive strips.   **Advantages** - Non-invasive - Allows visualization of relationship between contractions and FHR characteristics **Disadvantages** - **DOES NOT ASSESS CONTRACTION INTENSITY** -- Amplitude of UA displayed on the monitor and tracing has no relationship to the intensity of contractions or resting tone of the uterus - Difficult to monitor UA in early gestation - In cases of high BMI, it can be difficult to palpate contractions or obtain interpretable data from the toco - Some people find the belt confining and the toco button uncomfortable - Quality of the tracing may be affected by: - Size of maternal abdomen - Maternal position/movement - Position of toco on abdomen - Belt tightness - Baseline setting of the UA **2. Internal/Direct Monitoring** **a) Uterine Activity: Intra-Uterine Pressure Catheter (IUPC)**  **Intra-Uterine Pressure Catheter (IUPC)** - **IUPC placed through the cervix into the uterine cavity.** - **Sensor-tipped transducer transmits intra-uterine pressure changes in mmHg.** - **IUPC cable is secured to the leg.** **Advantages** - Accurately monitors uterine activity: including uterine resting tone, contraction intensity in mmHg, contraction frequency and duration - Allows greater freedom of movement **Disadvantages** - Invasive - Requires cervical dilation of 2--3cms and ruptured membranes - Increases risk of infection **Indications** An IUPC may be considered: - When it is difficult to palpate uterine contractions - With the administration of oxytocin when: - labour dystocia is suspected - there is the presence of a uterine scar - doses greater than 30 milliunits/min are being administered - To provide amnioinfusion to treat variable decelerations **Contraindications** - Undiagnosed vaginal bleeding (relative contraindication) - Vaginal or intrauterine infection - Caution with blood-born infections (e.g. HIV, hepatitis) **Risks **(rare and minimized by proper insertion and aseptic technique) - Uterine perforation - Placental trauma - Fetal trauma - Uterine infection - Umbilical cord prolapse - **b) Fetal Heart Rate: Fetal Spiral Electrode **(FSE or "scalp clip")** **via fetal electro-cardiogram (FECG) **Advantages** - Continuous, accurate assessment of FHR by fetal ECG (FECG)\* - Comfortable and allows greater freedom of movement - Can detect FHR arrhythmias **Disadvantages** - Invasive - Requires cervical dilation and ruptured membranes - In the presence of fetal demise, the fetal spiral electrode can pick up the maternal heart rate. **Indications** - When ultrasound data is inadequate for interpretation - When unable to assess the FHR with any other method **Contraindications** - Vaginal or intrauterine infection - Any contraindication to vaginal birth (e.g. placenta previa, active genital herpes) - Caution with blood-born infections (e.g. HIV, hepatitis) - Fetal thrombocytopenia or hemorrhagic complications - Face presentation - Unknown presenting part *Note: Intrauterine fetal monitoring is an independent risk factor for neonatal GBS disease (OR 1.94, 95% CI 1.09 -- 3.42). Although more research on this issue is necessary, this suggests that caution should be used when considering the use of a FSE in patients known to be colonized with GBS (Adair et. al., 2003).* **Risks **(rare and minimized by proper insertion, removal and aseptic technique) - Fetal trauma - Infection ### **Obtaining Interpretable Data** A clear continuous FHR tracing, maternal heart rate assessment, and uterine activity pattern recorded on the tracing allows for accurate interpretation.  Uninterpretable Tracing: An uninterpretable tracing is one which does not contain enough visually clear data to allow clinicians to interpret the information they are seeking. If EFM is indicated, it is the responsibility of the nurse or midwife to initiate troubleshooting efforts (see: Troubleshooting for Uninterpretable Tracings below)** **to ensure the EFM records the information necessary to interpret the FHS findings. If difficulties obtaining data are ongoing, the nurse or midwife should request internal monitoring of the fetus and/or uterine activity.  All efforts to obtain interpretable data should be documented. Artifact: Artifact is an electrocardiographic wave that arises from sources other than the fetal heart that interferes with the FHR display. Artifact occurs when the output signal produced is inaccurate because the external monitor is measuring: - the wrong input (e.g., the maternal heart rate or the unintended fetus in multiple gestations) - the correct input (the FHR) but displaying a misleading output signal by system errors such as doubling (when the FHR is below 50 bpm)  or halving (when FHR is over 240 bpm)  (AWHONN, 2018; Kiely, Oppenheimer and Dornan, 2019) Maternal heart rate (MHR) artifact has been found in 55% of EFM tracings. To avoid confusion, confirm the MHR (maternal pulse or O~2~ saturation monitor confirmed by palpation). Some EFM monitors provide the option of monitoring the MHR and FHR simultaneously. When the MHR or FHR are similar, these monitors may emit "Coincidence Alarms" indicating the supposed FHR may be maternal. Whenever there is uncertainty between the FHR and MHR, the MHR MUST be confirmed by palpation and documented. Providers need to be knowledgeable about the monitoring equipment used in their facilities, including the appropriate responses to alarms. **a)  Artifact from external ultrasound** - Can be characterized by empty spaces and "chicken scratches", which make it difficult to determine the baseline (image 1). - Can also look like small vertical lines that obscure the baseline to give a false impression of moderate variability (image 2). - It is important to differentiate between true variability and artifact. Image 1 Image 2  **b) Artifact from internal fetal spiral electrode** - This type of artifact appears as long and uneven vertical lines across the FHR graph (image 3). Image 3 Troubleshooting for Uninterpretable Tracings and Artifacts: If the FHR tracing is uninterpretable or contains artifacts, consider the following: - Is the artifact machine-generated? Check all connections and ensure the monitor functions properly. - Are the tocotransducer, ultrasound transducer and/or fetal spiral electrode applied correctly? - If external monitoring is used, reposition transducers in an attempt to obtain a clear continuous signal. - Anticipate the need for internal monitoring if unable to maintain a technically adequate tracing despite interventions using external monitoring. - If a fetal spiral electrode is in place, check for disconnection from the fetus or the monitor. - Auscultate the FHR to obtain audible FHR characteristics. - Are you able to differentiate between the fetal heart rate and the maternal heart rate? - Is there evidence of fetal arrhythmia (irregular rhythm)? **Table 6.3** +-----------------------------------+-----------------------------------+ | **Troubleshooting poor signal | | | acquisition in EFM** | | +===================================+===================================+ | **Potential Causes** | **Strategies** | +-----------------------------------+-----------------------------------+ | **Maternal** | - Ensure equipment is working | | | properly | | - High BMI, abdominal pannus | | | | - Check all connections | | - Polyhydramnios | | | | - External monitor: reposition | | - Maternal movement | patient and/or transducer(s) | | | | | - Artifact (e.g. maternal | - Verify UA and resting tone by | | pulse) | palpation | | | | | | - Verify FHR by auscultation or | | | ultrasound and ensure best | | | device placement over/close | | | to fetal heart | | | | | | - Determine the need for FSE | | | and/or IUPC if external | | | monitor tracing continues to | | | be unclear or uninterpretable | | | | | | - If using IUPC, verify | | | contractions by palpation | +-----------------------------------+-----------------------------------+ | **Fetal** | | | | | | - Fetal position | | | | | | - Fetal movement | | | | | | - Intrauterine death | | | | | | - Cardiac arrhythmia | | | | | | - Multiple fetuses | | +-----------------------------------+-----------------------------------+ | BMI = Body mass index; FHR = | | | Fetal Heart Rate; FSE = Fetal | | | Spiral Electrode; IUPC = | | | Intrauterine Pressure Catheter UA | | | = Uterine activity | | +-----------------------------------+-----------------------------------+ EFM Graph Range and Paper Speed 1\. Graph Range Before interpreting EFM data, it is essential to know the type of monitor paper that is used as they differ between monitor models and by institution. Some papers have FHR graph scales of 10-bpm increments and others of 5-bpm increments. The uterine activity scales also differ. On the monitor tracings pictured below, note that the uterine activity portion of the paper ranges from 0--100. These numbers depict intrauterine pressure in mmHg, and therefore are only applicable when an intrauterine pressure catheter is used. In these examples, an external tocotransducer is used, and the uterine resting tone is depicted at about 20mmHg. Monitors are manually set at this level to ensure the uterine resting tone can be more easily visualized. The actual uterine resting tone obtained by IUPC is about 5-15 mmHg. 2\. Paper Speed All professionals must be familiar with the paper speed used in their institution to avoid misinterpretation.  Paper speed for EFM tracings can be set at 1, 2, or 3 cm/min.  The SOGC (2020) has recommended that Canadian facilities adopt a universal paper speed of 3 cm/min to facilitate national consistency in practice, educational materials, interdisciplinary training and research endeavors. Visually, an EFM tracing speed of 3 cm/min is also easier to interpret as data is spread over 3 cm versus the faster speeds. This online learning module provides examples in all 3 speeds for learning purposes.  Learners should defer to activities in 3cm/min if not currently employed in intrapartum care. Otherwise, learners should defer to the paper speed currently in use by the intrapartum unit within their facility. The paper speed should never be changed within the same facility for various purposes. **Types of Fetal Monitor Paper ** Fetal tracings may be at 1, 2 or 3 cm/min. The main difference is visual. *Click the tabs below to view how 1 minute in time varies from 6 blocks at 3 cm/min, 4 blocks at 2 cm/min, and 2 blocks at 1 cm/min.* 3 cm/min Fetal tracings at 3 cm/min use 6 blocks per minute (10 seconds/block). For 10 minutes of time, a tracing at 3 cm/min will use 60 blocks. The area between the dark lines is 1 minute of time. 2 cm/min Fetal tracings at 2 cm/min use 4 blocks per minute (15 seconds/block). For 10 minutes of time, a tracing at 2 cm/min will use 40 blocks. The area between the number markings is 5 minutes of time. So between dark lines is 1.5 minutes of time 1 cm/min Fetal tracings at 1 cm/min use 2 blocks per minute (30 seconds/block). For 10 minutes of time, a tracing at 1 cm/min will use 20 blocks. The area between the dark lines is 3 minutes of time. ### **Systematic Interpretation of EFM Tracings** - A systematic approach to assessment of EFM is necessary to ensure all characteristics of the tracing and clinical picture are assessed and documented. - The SOGC recommends use of the NICHD (Macones, 2008) terminology when describing FHR characteristics of an EFM tracing (Dore & Ehman, 2020). - EFM patterns should always be assessed in association with uterine contractions. ##### ##### STEP 1 - When initiating EFM a\) Confirm the indication for continuous electronic monitoring b) Ensure that the date and time printing on the tracing correspond with the official date and time. c) Ensure that coincident alarms, archiving and/or printing of tracing are enabled and set according to institutional policy. d) Ascertain the paper speed and graph range. e) Confirm the mode of monitoring - external or internal. f) Assess the quality of the signal acquisition: - - - - - ##### ##### STEP 2 - Assess and interpret  a\) the uterine activity pattern b) the baseline FHR c) the baseline variability d) presence of fetal heart rate accelerations e) presence of periodic (with contractions) or episodic (not associated with contractions) decelerations: Early, late, uncomplicated or complicated variable, prolonged, episodic gradual deceleration ##### ##### STEP 3 - Classify the FHS findings and interpret in light of the total clinical situation a) **Normal **= no evidence of fetal compromise b) **Atypical **= physiologic response c) **Abnormal **= possible fetal compromise Does the interpretation and classification correlate with gestational age, pregnancy history, labour progress, risk factors (see [[Table 6.1]](https://elearning.ubccpd.ca/mod/lesson/view.php?id=8734&pageid=14227)), fetal behavioural state, or other extrinsic factors likely to influence the FHR? ##### ##### STEP 4 - Document and communicate systematically and clearly   **Table 6.4** +-----------------------------------+-----------------------------------+ | **Steps in Systematic | | | Interpretation of EFM Tracings** | | +===================================+===================================+ | **Check monitor** | Clock, alarms, paper speed, graph | | | range, external versus internal | | | monitoring, tracing quality | +-----------------------------------+-----------------------------------+ | **Interpret** | Uterine activity | | | | | | Baseline FHR | | | | | | Variability | | | | | | Presence of accelerations | | | | | | Presence of decelerations | +-----------------------------------+-----------------------------------+ | **Classify and correlate with | **NORMAL** | | clinical situation** | | | | **ATYPICAL** | | | | | | **ABNORMAL** | +-----------------------------------+-----------------------------------+ | **Document and communicate** | Risk factors | | | | | | History | | | | | | FHR findings and classification | | | | | | Overall impression and plan | | | | | | Interventions and associated | | | maternal or fetal response | +-----------------------------------+-----------------------------------+   EFM Tracing Characteristics Uterine Activity For detailed information on assessment of uterine activity - See [Module 4: Uterine Activity](https://elearning.ubccpd.ca/mod/lesson/view.php?id=8729&pageid=14208&startlastseen=no) Contraction frequency is determined by counting the number of contractions in a 10-minute window averaged over 30 minutes. - Contraction duration is calculated by counting from the beginning to the end of the contraction. - Uterine resting phase is determined by counting from the end of one contraction to the beginning of the next contraction. - Uteroplacental flow ceases at IU pressures of ≥50 mmHg - Resting tone (determined by IU pressure) \>25 mmHg is considered hypertonic - The terms hyperstimulation and hypercontractility are not defined and should be abandoned (Macones, 2008). **Table 6.5** +-----------------------+-----------------------+-----------------------+ | **Normal Uterine | | | | Activity and | | | | Tachysystole** | | | +=======================+=======================+=======================+ | **Characteristic** | **Normal** | **Tachysystole** | | | | | | | | Term for all forms of | | | | excessive UA; | | | | | | | | includes [any]{.under | | | | line} of | | | | the following:[\ | | | | ](file:///T:%5C%5CSPE | | | | CIAL%20PROJECTS%5C%5C | | | | Fetal%20Health%20Surv | | | | eillance%20Online%20M | | | | odules%5C%5CFundament | | | | als%20Course%5C%5COnl | | | | ine%20Module%20Develo | | | | pment%5C%5C2020%20upd | | | | ates%5C%5CFHS%20Onlin | | | | e%20Manual%20Chapter% | | | | 206%20EFM_10.21.2020% | | | | 20FINAL.doc#_msocom_1 | | | | ) | +-----------------------+-----------------------+-----------------------+ | Frequency | ≤5 contractions in 10 | \>5 contractions in | | | minutes averaged over | 10 minutes averaged | | | 30 minutes | over 30 minutes | +-----------------------+-----------------------+-----------------------+ | Duration | ≤90 seconds | \>90 seconds | +-----------------------+-----------------------+-----------------------+ | Intensity | Palpation: mild, | IUPC: ≥75 mmHg above | | | moderate or strong | the baseline except | | | | in second stage | | | IUPC: \>25mmHg and | | | | \