Category II Tracings: Does Fetal Resuscitation Work? Brian L. - - PowerPoint PPT Presentation

6/8/2018 1

Category II Tracings:

Brian L. Shaffer, MD Associate Professor Maternal Fetal Medicine Doernbecher Fetal Therapy June 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): Pathophysiology

Oxygen Delivery to the Fetus

Maternal 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

6/8/2018 2

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 pushing Administer 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

6/8/2018 3

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

6/8/2018 4

IUR: IV Fluid Bolus

Neuraxial 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 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, 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

6/8/2018 5

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 activity

Terbutaline 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 Outcomes

Pullen KM AJOG 2007

6/8/2018 6

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 Amnioinfusion
• E. 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”

6/8/2018 7

Audience Poll

29 yo G1 at 41 5/7 weeks IOL now pushing for 1h. +1 OP FHR: 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

6/8/2018 8

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 Hyperoxia

may 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

6/8/2018 9

O2 administration – Controversy O2 administration – Controversy O2 administration – Controversy O2 administration – Controversy

6/8/2018 10

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

• xygen 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