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37 Cards in this Set
- Front
- Back
Factors that could have adverse effect on FHR
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1. Intrinsic fetal disease
2. Placenta disease 3. Cord compression - intermittent during labor after ROM 4. Maternal disease 5. Drugs administered for analgesia/ anesthesia 6. Maternal hypotension from supine position |
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Auscultation
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1. Doppler - hand held; used in clinics- for low risk patients only
2. Ultrasound transducer 3. Fetoscope - auscultate full 60 seconds, counted in beats per minute - Before, during, and after uterine contraction *In low risk patients, done q30min. (1st stage of labor), q15min. (2nd stage of labor) |
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Electronic Fetal Monitor - external
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External
- Ultrasound - fetal HR - baseline rate, cariability, periodic patterns - Tocodynamometer - measures uterine contractions; frequency duration - can NOT measure intensity |
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Electronic Fetal Monitor - internal
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1. Fetal Scalp electrode (used in obese moms) - fetal HR
2. Intrauterine pressure catheter (IUPC) - measures frequency, duration, intensity (MVUs - montevideo Units), and resting tone |
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Baseline
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The approximate mean FHR rounded to increments of 5 beats/min. during a 10 min. segment, excluding:
1. periodic or episodic changes (accelerations, decelerations) 2. Periods of marked FHR variability - 25 bpm or more 3. Segments of baseline that differ by >25 beats/min. Normal = 110-160 bpm Bradycardia = <110bpm (SOS) Tachycardia = > 160 bpm |
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Maternal Causes of bradycardia
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1. Maternal position - supine or mom lying on cord
2. Maternal hypotension - positioning or epidural 3. Drug response - sedatives 4. Connective tissue disease (SLE) - lupus 5. Prolonged maternal hypoglycemia |
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Fetal Causes of bradycardia
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1. Mature parasympathetic nervous system
* 2. Intermittent umbilical cord occlusion or prolapsed cord * 3. Decompensated fetus - no O2 reserves 4. Hypothermia - usually not measured 5. Cardiac conduction defect * 6. Vagal stimulation - rapid descent - ready to deliver |
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Maternal causes for tachycardia
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1. Fever - antibiotics started to prevent transmission to fetus
2. Infection 3. Dehydration 4. Hyperthyroidism - rare 5. Endogenous adrenaline/ anxiety 6. Medications/ drugs 7. Anemia |
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Fetal causes for tachycardia
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1. Infection - mom gets antibiotics; ARF sepsis
2. Prolonged fetal activity or stimulation 3. Compensatory effect following hypoxia 4. chronic hypoxia 5. Cardiac abnormalities, heart failure - preemies = immature PNS 6. Fetal dysrrhythmias 7. Prematurity 8. Congenital anomalies |
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Baseline Variability
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single most important characteristic of FHR - ensures acid/base balance; specifically ensures lack of metabolic acidosis
- Fluctuation in the baseline FHR of two cycles/ min. or greater - Represents the interplay and balance between the sympathetic and parasympathetic divisions of the autonomic nervous system |
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Classifications of variability
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Absent - undetectable (nonreassuring)
Minimal - undetectable/ < 5 bpm Moderate - 6-25 bpm Marked - >25 bpm |
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Decreased variability
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Causes include but are not limited to:
1. HYPOXEMIA/ ACIDOSIS (ABSENT ONLY) 2. Drugs - sedatives 3. Fetal sleep cycles - < 20 min. duration 4. Congenital anomalies |
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Absent Variability
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emergency - notify midwife + physician
- Abnormal - unable to rule out fetal acidosis *Metabolic acidosis is the only link to neurologic injury in baby |
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Sinusoidal Baseline
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Characterized by smooth, sine wive-like pattern or regular frequency and amplitude
Still considered absent variability because it is too regular - nonreassuring |
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Evens associated with sinusoidal
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1. Severe fetal anemia
2. Rh isoimmunization 3. Abruption - fetal/ maternal hemorrhage 4. Sever fetal acidosis |
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Accelerations
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Reassuring - sign of fetal well-being
>32 weeks Abrupt increase (defined as onset of acceleration to peak in <30 seconds) in FHR above the baseline - Acme is > 15 bpm above the baseline and last > 15 seconds and < 2 min. from onset to return to baseline If < 32 weeks, acme > 10 bpm above baseline with duration of > 10 seconds |
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Prolonged acceleration
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> 2 min. < 10 min.
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Early decelerations
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- Gradual decrease (onset of develeration to nadir > 30 seconds) and to return to baseline FHR associated with uterine contration
- Nadir of deceleration occurs as the same time as the contration Mirrors contraction |
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Physiology of early deceleration
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Reflex vagal response to head compression
Not associated with oxygenation Seen most in 1st part of active phase of labor |
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Late decelerations
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- Gradual decrease (onset of deceleration to nadir > 30 seconds) and return to baseline associated with uterine contraction
- Nadir of deceration occurs after the peak of the contraction |
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Physiology of late deceleration
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1. Dimished uterine blood flow with uterine contraction
2. Critical reduction of pO2 following peak of UC 3. Hypoxic slowing of heart rate 4. Uteroplaecental insufficiency (UPI) |
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Causes of Uteroplacental insufficiency
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1. Maternal disease
2. Preeclampsia 3. Diabetes Mellitus 4. Too many uterine contractions 5. Fetal anemia 6. Infection |
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Variable decelerations
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Abrupt decrease (onset of deceleration to beginning of nadir < 30 sec.) in FHR of > 15 bpm and lasting >15 sec. and < 2 min. from onset to return to baseline
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Physiology of variable deceleration
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1. Umbilical cord compression
2. Stimulation of baroreceptors - response originates in carotid bodies and aortic arch; transmitted to the midbrain and then to PNS; decrease in FHR |
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Etiology of variable decelerations
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1. Short umbilical cord
2. Nuchal cord 3. Body entaglement 4. Prolapse cord 5. Second stage of labor 6. Decreased amniotic fluid 7. knot in cord |
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Prolonged Decelerations
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Decrease in FHR from baseline for > 15 bpm, lasting > 2 min., but < 10 min. from onset to return to baseline
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Etiology of prolonged decerations
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1. Maternal hypotension
2. Cord prolapse 3. Rapid cervical change 4. Sudden fetal descent 5. Uterine hypertonus - too frequent contractions and resting tone is high |
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Interpretation of Fetal Heart Rate Patterns - category I (Normal)
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Include all of the followin:
1. baseline rate 110-160 bpm 2. Baseline cariability - moderate 3. Late or variable decelerations absent 4. Early decelerations present or absent 5. Accelerations persent or absent - Strongly predictive of normal fetal acid/ base status at the time of observation - Followed routinely - no action required |
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Interpretation of Fetal Heart Rate Patterns - Category II (Indeterminate)
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May include any of the following:
1. Baseline rate - bradycardia not accompanied by absent baseline variability 2. Tachycardia 3. Baseline variability = minimal, absent w/o recurrent decelerations, or marked 4. Accelerations - absent after fetal acoustic stimulation 5. Periodic or episodic decelerations - recurrent variable decelerations w/ minimal or moderate baseline variability; prolonged deceleration; recurrent late decelerations with moderate variability - Not predictive of abnormal acid-base status - Do not have adequate evidence at present to classify into I or III - Continue surveillance and reevaluate |
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Interpretation of Fetal Heart Rate Patterns - Categoy III (Abnormal)
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1. Absent baseline variability and any of the following:
- recurrent late or variable decelerations; bradycardia 2. Sinusoidal pattern - CANNOT RULE OUT METABOLIC ACIDOSIS - Are predictive of abnormal fetal acid/base status at time of observation - Requires prompt evaluation: - Maternal oxygen, position change, D/C labor stimulation, treat hypotension It is not adequate to only get the midwife in, must also get the M.D. who covers the midwife |
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Nursing Interventions - late decelerations
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1. Lateral position
2. Oxygen 10 L face mask 3. 500 ml IVF bolus - increase maternal cardiac output 4. Evaluate oxytocin and uterine contraction pattern 5. Evaluate variability 6. Notify M.D. and midwife |
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Nursing Interventions - variable decelerations
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1. Reposition (right, left, knee chest)
2. Cervical exam - check for cord prolapse, labor progress 3. Evaluate variability 4. Notify M.D./ CNM for repetitive |
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Nursing Interventions - prolonged decelerations
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1. ID cause
2. Notify M.D./ CNM and anesthesia |
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Nursing Interventions - prolonged decelerations s/t maternal hypotension
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1. Assess BP q2-3min.
2. IVF bolus 3. Lateral, recumbent position 4. Oxygen 10 L face mask 5. Notify anesthesia 6. Notify M.D./ C.N.M. 7. Prep for delivery (d/c Foley, shave, prep) |
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Nursing Interventions - prolonged decelerations s/t cord prolapse, sudden fetal descent, or rapid cervical change
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1. Cervical exam
2. Notify anesthesia 3. Notify M.D./ C.N.M. - delivery 4. Prep for delivery 5. Oxygen 10 L face mask |
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Nursing Interventions - prolonged decelerations s/t uterine hypertonus
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1. Assess uterine tone
2. Decrease and/ or d/c pitocin 3. Terbutaline 0.25 mg IV to bedside 4. Prepare for delivery 5. Oxygen 10 L face mask |
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Take Home Message r/t FHR monitoring
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1. When in doubt notify MD
2. Make diagnosis 3. Know your terminology 4. Evaluate uterine activity - do you need to D/C pitocin? 5. Reposition 6. Will oxygen help? |