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27 Cards in this Set
- Front
- Back
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goals of intrapartum FHR monitoring |
- to identify and differentiate the normal (reassuring) patterns from the abnormal (non reassuring ) patterns, which can indicate fetal compromise |
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fetal hypoxemia |
- abnormal FHR patterns are associated with this - a deficiency of oxygen in the arterial blood - if not corrected can turn into fetal hyoxia |
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fetal hypoxia |
- inadequate supply of oxygen at the cellular level that can cause metabolic acidosis |
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asphyxia |
- used when fetal hypoxia results in metabolic acidosis |
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intermittent auscultation |
- involves listening to fetal heart sounds at periodic intervals to assess the FHR - can be performed with a pinard stethoscope, doppler ultrasound, an ultrasound stethoscope or a DeLee Hillis fetoscope. |
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Contraction intensity
Contraction duration
Contraction frequency |
- usually described as mild, moderate or strong
- is measured in seconds, from the beginning to the end of the contraction
- is measured in minutes, from the beginning of one contraction to the beginning of the next.
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external mode to monitor FHR Ultrasound transducer |
- high frequency sound waves reflect mechanical action of fetal heart rate ; noninvasive, does not require rupture of membranes or cervical dilation, used during both antepartum and intrapartum periods |
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external mode of uterine activity
Tocotransducer |
- monitors frequency and duration of contractions by means of pressure-sensing device applied to maternal abdomen; used during both antepartum and intrapartum periods. |
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internal mode to monitor FHR
spiral electrode |
- converts fetal ECG as obtained from presenting part of FHR via cardiotachometer; can be used only when membranes are ruptured and cervix is sufficiently dilated during intrapartum period; electrode penetrates into fetal presenting part by 1.5 mm and must be attached securely to ensure good signal |
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Internal mode to monitor uterine activity
Intrauterine pressure catheter (IUPC) |
- monitors frequency, duration, and intensity of contractions - two types of IUPC's: fluid filled system and solid catheter- both measure intrauterine pressure at catheter tip and convert pressure into millimeters of mercury on uterine activity panel of strip chart; both can be used only when membranes are ruptured and cerix is sufficiently dilated during intrapartum period. |
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portable telemetry |
- allows observation of FHR and UC patterns by means of centrally located electronic display stations - portable units permit the woman to walk around during electronic monitoring |
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Montevideo units |
- are calculated by subtracting the baseline uterine pressure from the peak contraction pressure for each contraction that occurs in a 10-minute window and then adding together the pressures generated by each contraction that occurs during the period of time. - Spontaneous labor usually begins when MVU's are between 80-120 - uterine activity during the first stage of normal labor rarely exceeds 250 MVU's |
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base line FHR |
- is the average rate during a 10-minute segment that excludes periodic or episodic changes, periods of marked variability, and segments of the baseline that differ by more than 25 beats per minute. - there must be at least 2 minutes of interpretable baseline data in a 10 minute segment of tracing to determine the baseline FHR - after 10 minutes of tracing is observed, the approximate mean rate is rounded to the closest 5 beats per minute interval. - normal FHR is 110-160 bpm |
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Variability of the FHR |
- irregular waves or fluctuations in the baseline FHR of two cycles per minute or greater -characteristic of the baseline FHR and does not include accelerations or decelerations of FHR -four possible categories: absent, minimal, moderate and marked. - absent or minimal is classified as either abnormal or indeterminate. can result from fetal hypoxemia and metabolic acidemia, congenital anomalies, pre-existing neurologic injury, CNS depressant medications (analgesic, narcotics, barbs, and other general anesthetics) - moderate variability is considered normal. highly predictive of normal fetal acid-base. |
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tachycardia |
- FHR greater than 160 bpm lasting longer than 10 minutes - Possible causes: early fetal hypoxemia, fetal cardiac arrhythmias, maternal fever, infection (including chorioamnionitis), parasympatholytic drugs (atropine, hydroxyzine), Beta sympathomimetic drugs (terbutaline), maternal hyperthyroidism, fetal anemia, and drugs (caffeine, cocaine, methamphetamines) - clinical significance: persistent tachycardia in absence of periodic changes does not appear serious in terms of neonatal outcome (especially if mom has a fever); is abnormal when associated with late decelerations, severe variable decelerations or absent variability. - Interventions: reduce maternal fever with antipyretics as ordered and cooling measures; O2 at 10 L/min by nonrebreather face mask; carry out HCP's orders on alleviating cause. |
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Bradycardia |
- FHR less than 110 beats per minute lasting greater than 10 minutes - Possible causes: atrioventricular dissociation (heart block), structural defects, viral infections (cytomegalovirus), medications, fetal heart failure , maternal hypoglycemia, maternal hypothermia - Clinical significance: baseline bradycardia alone is not specifically related to fetal oxygenation. depends on underlying cause and accompanying FHR patterns, including variability, accelerations or decelerations. Interventions: dependent on cause. |
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accelerations |
-abrupt (onset to peak less than 30 seconds) increases in FHR above the base line - the peak is at least 15 beats/min above the baseline, and the accelerations last 15 seconds or more, with the return to baseline less than 2 minutes from the beginning of the acceleration - before 32 weeks of gestation, it is the peak of 10 beats/min or more above baseline and a duration for at least 10 seconds. -considered an indication of fetal well being representing fetal alertness or arousal states. - causes: spontaneous fetal movement, vaginal examination, electrode application, fetal scalp stimulation, fetal reaction to external sounds, breech presentation, occiput posterior position, uterine contractions, fundal pressure and abdominal palpation. - |
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decelerations |
- caused by dominance of a parasympathetic response may be benign or abnormal . - categorized as early, late, variable or prolonged - described by their visual relation to the onset and end of a contraction and by their shape |
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early deceleration |
- is visually apparent, gradual (onset to lowest point greater than 30 seconds) decrease and return to baseline FHR associated with UCs. - causes: head compression resulting from: uterine contractions, vaginal examination, fundal pressure or placement of internal mode of monitoring -Clinical significance: normal pattern; not associated with fetal hypoxemia, academia or low Apgar scores. |
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late decelerations |
- is a visually apparent, gradual (onset to lowest point greater then 30 seconds) decrease in and return to baseline FHR associated with UCs. - begins after the contraction has started and the lowest point occurs after the peak of the contraction. -usually does not return to baseline until after the contraction is over. - cause: disruption of oxygen transfer from environment to fetus caused by: uterine tachysystole, maternal supine hypotension, epidural or spinal anesthesia, placenta previa, placenta abrupt ions, hypertensive disorders,post maturity, intrauterine growth restriction, diabetes, intraamniotic infection. - clinical significance: abnormal pattern associated with fetal hypoxemia, academia, and low APGAR scores; considered ominous if persistent and uncorrected, especially when associated with absent or minimal baseline variability. - Nursing interventions: change maternal position (lateral), correct maternal hypotension by elevating legs, increase rate of maintenance IV solution, palpate uterus to assess for tachysystole, discontinue oxytocin if infusing, admin O2 8-10 L by nonrebreather mask, notify doc, consider internal monitoring for more accurate fetal and uterine assessment, and assist with birth if pattern can't be corrected. |
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variable decelerations |
- is defines as a visually abrupt (onset to lowest point less than 30 seconds) and apparent decrease in FHR below baseline - is at least 15 beats/min or more below the baseline, lasts at least 15 seconds and returns to baseline in less than 2 minutes from time of onset. - nadir: lowest point of deceleration - recurrent variable decelerations indicate repetitive disruption in 02 supply of the fetus - cause: umbilical cord compression caused by: maternal position with cord between fetus and maternal pelvis, cord around fetal neck/arm/leg/or other body part, short cord, knot in cord or prolapsed cord Clinical Significance: variable decelerations occur in approximately 50% of all labors and usually are transient and correctable. Nursing Interventions: change maternal position (side to side, knees to chest), discontinue oxytocin if infusing, admin O2 8-10 liters by nonrebreather face mask, notify doc, assist with vaginal or speculum examination to assess for cord prolapse, assist with amnioinfusion if ordered, and assist with birth if pattern not corrected. |
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prolonged decelerations |
- is a visual apparent decrease (may be either gradual or abrupt) in FHR of at least 15 beats/min below the baseline and lasting more than 2 minutes but less than 10 minutes. - deceleration lasting more than 10 minutes is considered a baseline change - examples: conditions that cause an interruption in fetal oxygen supply long enough to produce a prolonged deceleration include: maternal hypotension, uterine tachsystole or rupture, extreme placental insufficiency and prolonged cord compression of prolapse |
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management of abnormal fetal heart rate patterns |
- basic interventions: admin O2 by nonrebreather face mask at 10L/min for 15-30 minutes, assist woman to a side lying lateral position, and increase maternal blood volume by increasing rate of primary IV infusion.
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interventions for maternal hypotension |
- increase rate of primary IV infusion - change to lateral or trendelenburg positioning - administer ephedrine or phenylephrine if other measures are unsuccessful in increasing blood pressure
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interventions for uterine tachysystole |
- reduce or discontinue dose of any uterine stimulants in use (oxytocin) - administer uterine relaxant (tocolytic) (terbutaline)
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interventions for abnormal fetal heart rate pattern during second stage of labor |
- use open-glottis pushing - use fewer pushing efforts during each contraction, make individual pushing efforts shorter, push only with every other or every third contraction - push only with perceived urge to push (in women with regional anesthesia) |
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amnioinfusion |
- an infusion of room temperature isotonic fluid (usually NS or LR) into the uterine cavity if the volume of amniotic fluid is low - purpose is to relieve intermittent umbilical cord compression that results in variable decelerations and transient fetal hypoxemia by restoring the amniotic fluid volume to a normal or near normal level - women with abnormally small amounts of manioc fluid or no amniotic fluid are candidates for this. -risks: overdistention of the uterine cavity and increased uterine tone. |
