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Category II Tracings:

Brian L. Shaffer, MDAssociate ProfessorMaternal Fetal MedicineDoernbecher Fetal TherapyJune 8, 2018

Does Fetal Resuscitation Work?

Disclosures

• I have nothing to disclose

Objectives: In Utero Resuscitation in Cat II FHR

• Pathophysiology – O2 transfer to fetus– Maternal status

– Uterine activity

– Umbilical cord

• Resuscitative options:– “Amelioration of the fetal heart rate tracing” - JTP

– Help or Harm – What’s the evidence?

– “Routinely used, poorly studied”

Intrauterine Resuscitation (IUR): PathophysiologyOxygen Delivery to the FetusMaternal status

Maternal Oxygenation (Environment)

Cardio-Pulmonary status (Cardiac Output)

Vasculature

Can be interrupted Uterus (Activity)

diminished along Placenta

this pathway Cord (Compression)

Fetal status

Goal: Prevent, Identify, and ameliorate fetal acidemia

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IUR - Pathophysiology (cont.)

• Hypoxemia Anaerobic metabolism Lactate ↓pH

• FHR monitoring: indicate risk of acidemia– Cat I – very low risk

– Cat III – very high risk • Immediate IUR and if not successful….

• Expeditious delivery

• Very uncommon <1% of all FHR

IUR - Pathophysiology (cont.)

• Category II – not predictive of fetal-acid base status– Requires evaluation, continued surveillance and re-evaluation

– Common - 2h prior to delivery: ~40% of FHR is cat II

– Moderate variability & accelerations – Absence of acidemia

– More “abnormal” findings higher the probability of acidemia• Minimal variability, Decelerations, Tachycardia, etc…

• ~30% of fetuses demonstrate a “nonreassuring” pattern in labor– Nonreassuring ≠ acid base values

– With the limitations of FHR –• What can we do about it? – IUR!

IUR – Goals and Actions

Deliver O2 Lateral decubitus, IV fluid bolus

To Fetus Reduce/Stop uterotonics, Alter pushingAdminister O2 (Maternal)

↓ Uterine Lateral decubitus, IV fluid bolus,

Activity Reduce/Stop Uterotonics, Tocolytic

Goals “Resuscitation”

IUR – Goals and Actions

Alleviate cord Lateral decubitus, Amnioinfusion (stage I) Compression Alter pushing (every 2nd/3rd)

Treat maternal Lateral decubitus, IV fluids

Hypotension Meds: ephedrine, phenylephrine

• Must consider clinical context – parity, stage, chorio, etc.

• Characteristics of FHR, pattern evolution (~60 min)*

• Cascade of actions – position, IV fluids...

Goals “Resuscitation”

*Parer JT 2006 J Mat Fetal Neo Med

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IUR: Lateral decubitus position

• Lateral decubitus (Left or Right)– Supine position Aortocaval compression

• Decreases venous return & increases afterload

• Reduction of CO – up to 30%

– May use wedge

• Lateral position & Fetal O2 status– Lateral position compared with supine

• Normal FHR, small number of subjects

• Increased fetal O2 by fetal pulse ox (fetal SpO2)

• Left and right similar increased in SpO2

• Fetal SpO2 was lowest - supine hypotensive episode

Carbonne 1996 Obstet Gynecol; Simpson KR Am J Obstet Gynecol 2005

IUR: Lateral decubitus position

• Most common intervention

• May alleviate compression with uterine wall/fetal parts

• Prevents supine hypotension episode– May maximize maternal CO

• Left more commonly utilized– Both R&L may modify uterine blood flow and assist in

resolution of late decelerations

• First response to a “nonreassuring” pattern

Carbonne 1996 Obstet Gynecol; Simpson KR Am J Obstet Gynecol 2005

IUR: IV Fluid Bolus

Hypovolemia/Hypotension ↓ Uterine blood flow ↓Fetal O2

• IV fluid bolus – 500-1000cc NS/LR

• Do not utilize glucose containing IVF– Increased fetal lactate, decreased pH

– Increased risk for fetal hyperglycemia neo hypoglycemia hyperinsulinsim, jaundice, TTN

Simpson KR Obstet Gynecol 2005

IUR: IV fluid bolus – Fetal oxygenation Sp02

• IVF and fetal oxygen saturation (Sp02)– IOL, oxytocin, epidural, n=56, normal FHR

– 500 vs. 1000cc LR

– Increase fetal oxygen saturation (Sp02)• 1000cc increase in fetal SpO2 - 5.2%

• 500cc increase in fetal SpO2 - 3.7%

– Improved fetal SpO2 in normotensive, well hydrated patients

• Fetal pulse oxygenation?

• Caution: Pre-eclampsia, Magnesium Pulmonary edema

Simpson KR Obstet Gynecol 2005

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IUR: IV Fluid BolusNeuraxial anesthesia/Supine position (both!) Hypo-volemia/Hypotension ↓ Uterine blood flow ↓Fetal O2

Action: Lateral position, IVF bolus

• If not corrected – Ephedrine, phenylephrine– Ephedrine – mixed α and β agonist

• Epinephrine (α only) can constrict uterine blood flow

– Associated with marked FHR variability

• Data - Few studies• May reduce hypotension, but most benefit illustrated with high dose

– No longer utilized in contemporary anesthesia

• No clear benefit to FHR, hypotension – epidural, spinal

Hofmeyr Cochrane Review 2010

Audience Poll35 yo G2P1001 at 40 5/7 wks IOL for rapid labor and SVE of 6/80/0, oxytocin at 3mu/min FHR 150s min-mod variability, intermittent late and severe variable decelerations. Toco:q1-2

A. None, with some moderate variability the fetus is unlikely to be acidemic, AROM and glove up

B. Position change, Fluid bolus, O2 CD if not resolved

C. If B doesn’t work, AROM and Amnioinfusion

D. Oxytocin off, position change, IVF, Tocolytic if

E. No resolution 10 min

4% 2% 0%

85%

9%

IUR: Uterine activity

• Contraction - Intermittent interruption of O2/CO2 transfer– Tetany/Tachysystole ↓ Intervillous flow ↓Fetal O2

Anaerobic metabolism

Acidemia

• Reduction in UCs

improved perfusion

• Action: Uterotonics

Simpson KR Am J Obstet Gynecol 2008

IUR: Uterine activity

• Contraction - Intermittent interruption of O2/CO2 transfer– Tetany/Tachysystole ↓ Intervillous flow ↓Fetal O2

Anaerobic metabolism

Acidemia

• Reduction in UCs

improved perfusion

• Action: Uterotonics

• Limitation – pulse Ox

Simpson KR Am J Obstet Gynecol 2008

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IUR: Excessive Uterine activity

Tachysystole - >5 UCs in 10 min (30 minutes)

• Spontaneous

• Induction/Augmentation: (misoprostol, Oxytocin, etc.)

• Anesthesia – Intrathecal opioids/Response

ACTION

• Reduce/Stop Uterotonics

• Tocolytic– Terbutaline SQ or IV

– Nitroglycerine

– Magnesium

Audience Poll

35 yo G2P1001 at 40 5/7 wks IOL for rapid labor and SVE of 6/80/0, oxytocin at 3mu/min FHR 150s min-mod variability, int late and severe variable decelerations. Toco:q1-2 Which Tocolytic?

A. A IV terbutaline

B. B IV nitroglycerine

C. C IV Magnesium

D. D SQ terbutaline

E. E Atosiban

21%

1% 0%

76%

1%

IUR: Excessive Uterine activity

Terbutaline/Beta agonists vs. No medication

• Abnormal FHR, fetal scalp pH, randomized

• Neonate – decrease rate of acidemia

• Maternal – transient maternal tachycardia

Terbutaline (0.25mg SQ) vs. Magnesium (4gm bolus IV)

• Awaiting CD for FHR abnormalities

• Terbutaline reduced uterine activity (MVU)

• Magnesium no significantly reduced uterine activity– More neonates with CUA pH <7.2

Kulier R Cochrane review 2009

IUR: Excessive Uterine activityTerbutaline v Nitroglycerine (IV)

• Amelioration of nonreassuring FHR tracing, n=110– NRFHT

• Decels: Prolonged, late or severe variables;

• Tachycardia + min variability

– Success = complete resolution (10 min)

Terbutaline: – Fewer median UCs (2.9 vs. 4 UCs/10 min)

– Resolution of tachysystole (1.8 vs. 18.9%)

• Similar rates of successful resuscitation (72 vs. 64%, NS)

• Maternal MAP decreased with Nitroglycerine

• No differences in Ob OutcomesPullen KM AJOG 2007

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Audience Poll

29 yo G1 at 39 5/7 weeks with SOOC and SVE of 5/80/-1 FHR 150s mod variability and recurrent severe variables. Toco: q2-3

A. A: None, with mod variability - fetus is unlikely acidemic

B. B: Position change, Fluid bolus – “Fix” those variables

C. C: Position change, Fluid bolus and O2

D. D: If B doesn’t work, AROM and AmnioinfusionE. E: Cesarean: too remote from delivery

0%

16%

4%

53%

26%

IUR: Suspected umbilical cord compression

• Umbilical cord compression – recurrent severe variable decelerations despite position change

• Concept: alleviate cord compression via infusion of NS/LR into the uterus with IUPC

• Beware of iatrogenic poly – ensure fluid egress

Hofmeyr GJ, Cochrane Review 2012

IUR: Suspected umbilical cord compression

• 19 trials, n=>1000

• Reductions in: – FHR decelerations (RR 0.53)

– CD for NRFHT (RR 0.62) & Endometritis (RR 0.45)

– Apgar <7 at 5 min (RR 0.47)

– Meconium below cords (RR 0.53)

• Maternal risks– Appears to be generally safe, No increased risk in VBAC

Hofmeyr GJ, Cochrane Review 2012

IUR: Stage II Alternate Pushing

• Consider interruption of pushing fetus to recover

• Decrease frequency and length of each effort– 3-4 efforts for 6-8 seconds

• Effort with every other UC or every third

• Some advocate laboring down – cat II?

• Few adequate well designed trials to provide clear recommendations– “Street Smarts”

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Audience Poll

29 yo G1 at 41 5/7 weeks IOL now pushing for 1h. +1 OPFHR: tachycardia, min variability, intermittent lates.Position, IVF bolus, push every other - done. O2 at 10L/min, non- rebreather. How long?

A. A: 30 min

B. B: Until FHR improves significantly

C. C: 60 min

D. D: As long as it takes to move for CD

E. E: No limit, O2 is beneficial

34% 36%

13%14%

3%

IUR: Hyperoxygenation

• Recurrent late or prolonged decelerations– May represent fetal hypoxia

– Action: Increase delivery of O2 to fetus & prevent acidemia

• No studies: Maternal oxygen for fetal distress

• 6 studies, <100 women in labor without NRFHT– 10L/min, nonrebreather FiO2 of 80-100%, route/amount varied

– Increases fetal oxygenation (fetal SpO2, scalp/cord sample etc.)

– Improves FHR pattern

Fawole B, Cochrane Review 2012

Hyperoxygenation – Potential benefits

• Maternal O2 (40-100 FiO2), Term, Labor n=24

• 30 minutes on/off for each treatment

• Abnormal FHR– Intermittent or recurrent variable or late decelerations

– Decreased variability or tachycardia

• Increased mean fetal SpO2– 4.9 (FiO2 40%) to 6.5% (FiO2 100%)

• No outcomes/morbidity reported

Haydon ML 2006 Am J ObGyn

Hyperoxygenation – Potential benefits

• O2 with IVF and position change– Elective IOL, oxytocin, epidural, n=56, normal FHR

– Increase fetal Sp02 ~8.7%

– Effect lasted about 30 min after discontinued

– Effect was greater in fetuses with lower (<40%) saturations

• Fetal oxygen saturation is not utilized– Limited utility

Simpson KR Obstet Gynecol 2005

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Hyperoxygenation – Potential benefits

• Can O2 improved NRFHT? Treat/Limit/Reduce acidemia

• 100% O2, n=21, tachycardia, “type II dips”1

– Tachycardia, late decelerations resolved/improved

– NRFHT returned after O2 discontinued

• Other studies illustrated improved FHR characteristics– Resolution of late decelerations2

– Improved variability, non reactive reactive3

1) Althabe O Am J Obstet Gynecol 1967 2)Khazin Am J Obstet Gynecol 1971 3) Bartnicki In J Ob 1994

Hyperoxygenation - Potential harms

• Term RCT, stage 2, 10L O2 (FiO2 of 0.81)– n=86, O2 on for stage 2

– Mean 36 min O2, Stratified by >10 (prolonged) or <10min

– No CD for fetal indications, normal FHR

– Lower pH (<7.2) in those who had O2 (RR 3.51)

– CUA worse with O2 (pH, PO2, PCO2, base excess)

– Cord pH lower in prolonged O2 group (7.24 v 7.29 v. 7.31)• Statistical but not clinically different

• Methodological concerns

Thorp JA Am J Obstet Gynecol 1995

Hyperoxygenation - Potential harms

• Prospective cohort – composite morbidity, n=>7000– Death, MAS, intubation, ventilation, HIE, hypothermia

– Hyperoxemia –UV partial pressure O2 - >90thcentile • 80-90% of cohort had O2 (200 min)

– No difference in morbidity with and without hyperoxemia• 1.5% vs 1.3%

– Hyperoxemia plus acidemia (pH<7.1)• Increased composite morbidity (RR 2.3)

– O2 reoxygenation injury?

Raghuraman N Obstet Gynecol 2017

O2 administration – Harmful?

• Hypoxia leading to acidemia followed by Hyperoxiamay lead to injury– Oxygen free radicals oxidative stress injury

– Is oxidative stress causal or a consequence of the sequelae of hypoxia? Unknown in a fetus

• Neonatal resuscitation – recommend FiO2 of .21

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O2 administration – Controversy O2 administration – Controversy

O2 administration – Controversy O2 administration – Controversy

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O2 administration – Harmful?

• Abstract– Noninferiority

• O2 therapy – Second tier therapy– After position change, IVF fluid, stop/decrease uterotonics

• Unlikely needed if FHR has moderate variability

- If using, Discontinue when FHR is improved- Develop timing protocols

Conclusions – Intrauterine Resuscitation• Common, like FHR – IUR will be utilized

• Safe and potentially efficacious– IVF, position change, alternate push pattern – Individualized

• Safe and likely efficacious– Amnioinfusion – Severe variables, stage I

• Iatrogenic Polyhydramnios

– Stop uterotonics / Tocolytics – terbutaline• Maternal tachycardia

• Safety uncertain / Efficacy – short term– Hyperxoygenation – timing is everything

• Second tier approach – Shortest time feasible, be aware of

pattern evolution, remove if improvement

References

Parer JT, King T, Flanders S, et al. Fetal acidemia and electronic fetal heart rate patterns: is there evidence of an association? J Matern fetal Neo Med 2006;19:289-94.

Simpson KR James DC. Efficacy of intrauterine resuscitation techniques in improving fetal oxygen status during labor. Obstet Gynecol 2005;105:1362-8.

Carbonne B, Benachi A, Leveque ML, et al. Maternal position during labor: effects on fetal oxygen saturation measured by pulse oximetry. Obstet Gynecol 1996;88:797-800.

Kulier R, Hofmeyr GJ. Tocolytics for suspected intrapartum fetal distress. Cochrane Database of Systematic Reviews 1998, Issue 2. Art. No.: CD000035. DOI: 10.1002/14651858.CD000035.

Pullen KM, Riley ET, Waller SA, et al. Randomized comparison of intravenous terbutaline vs nitroglycerine for acure intrapartum fetal resuscitation. AM J Obstet Gynecol 2007 197:414.e1-414.e6.

Hofmeyr GJ, Lawrie TA. Amnioinfusion for potential or suspected umbilical cord compression in labour. Cochrane Database of Systematic Reviews 2012, Issue 1. Art. No.: CD000013. DOI: 10.1002/14651858.CD000013.pub2.

Haydon ML, Gorenberg DM, Nageotte MP et al. The effect of maternal oxygen administration on fetal pulse oximetry during labor in fetuses with nonreassuring fetal heart rate patterns. Am J Obstet Gynecol 2006;195:735-8.

Thorp JA, Trobough T Evans R, et al. The effect of maternal oxygen administration during the second stage of labor on umbilical cord blood gas values: a randomized controlled prospective trial. Am J Obstet Gynecol 1995;172:465-74.

References

Fawole B, Hofmeyr GJ. Maternal oxygen administration for fetal distress. Cochrane Database of Systematic Reviews 2012, Issue 12. Art. No. : CD000136. DOI: 10.1002/14651858.CD000136.pub2

Simpson KR, James DC. Effects of oxytocin-induced uterine hyperstimulation during labor on fetal oxygen status and fetal heart rate patterns. Am J Obstet Gynecol 2008;199:34.e1-.e5.

Althabe O Jr, Schwarcz RL, Pose SV et al. Effects on fetal heart rate and fetal pO2 of oxygen administration to the mother. Am J Obstet Gynecol 1967:98:858-70.

Khazin AF Hon EH, Hehre et al. Effects of maternal hyperoxia on the fetus. I. Oxygen Tension. Am J Obstet Gynecol. 1971;109:585-70.

Raghuraman W, Temming LA, Stout MJ et al. Intrauterine Hyperoxemia and Risk of Neonatal Morbidity. Obstet Gynecol 2017;129:676-82.

Hofmeyr GJ, Cyna AM, Middleton P. Prophylactic Intravenous preloading for regional anesthesia in labor. Cochrane Database 2004 Issue 4