O&G - Emergency C-section Flashcards
What options are there for Operative (instrumental) Vaginal delivery?
- Forceps
- Vacuum extractor
Note: both methods can be used for either non-rotational or rotational delivery
How common is operative (instrumental) vaginal delivery?
10-13% of deliveries
When can a vacuum extractor not be used for operational vaginal delivery?
< 34 + 0 weeks gestation
between 34-36 weeks is uncertain (done with caution)
What are the indications for operative vaginal delivery (OVD) mainly used?
- Presumed fetal compromise
- Shorten and ↓ effects of 2nd stage of labour on comorbidities e.g. HTN, cardiac disease, myasthenia gravis etc.
-
Inadequate progress:
- Nulliparous - failure to progress in 2nd stage of labour for 3-hrs with regional anaesthesia or 2-hrs without regional
- Multiparous - failure to progress in 2nd stage of labour for 2-hrs with regional anaesthesia or 1-hrs without regional
- Maternal exhaustion
What does rotational delivery refer to in OVD?
Use of instruments to expidite delivery of the baby whilst mimicking the the natural rotations that occur during vaginal delivery
What methods of monitoring might be used during labour?
- Vital signs - MEOWS
-
Auscultation of fetal heart rate
- Intermittently, via either Pinard stethoscope or Doppler US
- Record accelerations and decelerations if heard
- ↑ baseline fetal HR or decelerations –> measure more frequently, get help, offer CTG
- Continuous CTG (cardiotocography)
What are some indications for continuous CTG monitoring during labour?
Continuous CTG if any of the following at present at initial assesment or arise during labour:
- Maternal HR > 120 on 2 occasions, 30-mins apart
- temp > 38
- HTN - BP > 140/90 on 2 consecutive readings 30-mins apart
- severe HTN - BP > 160/110
- suspected chorioamnionitis or sepsis
- significant meconium
- fresh vaginal bleeding that develops in labour
- 2+ protein on urinalysis + 1 reading of BP > 140/90
- delay in 1st or 2nd stage of labour
- contractions > 60s long or > 5 contractions in 10 mins
- oxytocin use
What should also be offered to women requiring continuous CTG during labour?
Cardiac Telemetry
What are 3 risk factors for operative vaginal delivery?
Operative vaginal delivery is more common in:
- Primiparous women
- Supine & lithotomy positions
- Epidural anaesthesia
Lithotomy positon = on back with legs up, supported by stirrups (see image)
Why is 2-hrs of passive 2nd stage of labour reccommended in primiparous women with epidurals?
Primiparous women with epidurals are less likely to have rotational or mid-cavity operative interventions when pushing (active 2nd stage) was delayed by 1-2 hrs or until they had a strong urge to push
How is the acronym ‘DR C BRAVADO’ used to interpret a CTG?
- DR - Define Risk
- C - Contractions - no. in a 10 min period e.g. 3:10 (3 every 10 mins)
- BRa - Baseline Rate - avg HR in 10-min window (normal = 110-160)
- V - Variability
- A - Accelerations
- D - Decelerations
- O - Overall impression - Reassuring, suspicious or abnormal
Give some reasons why a pregnancy may be considered ‘High-risk’ as part of a DR C BRAVADO assessment of CTG.
Maternal illness:
- Gestational diabetes
- Hypertension
- Asthma
Obstetric complications:
- Multiple pregnancy
- Post-date gestation
- Hx of C-section
- Intrauterine growth restriction (FGR)
- Premature rupture of membranes
- Congenital malformations
- Oxytocin induction/augmentation of labour
- Pre-eclampsia
Other risk factors:
- Smoking
- Drug abuse
Name some causes of Fetal tachycardia?
- Fetal hypoxia
- Chorioamnionitis – if maternal fever also present
- Hyperthyroidism
- Fetal or maternal anaemia
- Fetal tachy-arrhythmia
When is it common to have a fetal HR of 100-120 BPM?
- Post-date gestation
- Occiput posterior or transverse presentations
Name some causes of severe fetal bradycardia.
- Prolonged cord compression
- Cord prolapse
- Epidural and spinal anaesthesia
- Maternal seizures
- Rapid fetal descent
What does Variability refer to on a CTG?
Baseline variability refers to variation of fetal HR from one beat to the next
- Variability is due to interaction of; NS, chemoreceptors, baroreceptors etc
- Normal variability –> indicates intact neurological system
-
Normal variability = 5-25 BPM
- Measured as dif in HR between peak & trough from one beat to next
-
Non-reassuring variability:
- < 5 BPM for 30-50 mins
- > 25 BPM for 15-25 mins
-
Abnormal variability:
- < 5 BPM for > 50 mins
- > 25 BPM for > 25 mins
What are Accelerations on a CTG?
Accelerations:
- Accelerations = abrupt ↑ in baseline fetal HR of > 15 BPM for > 15 seconds
- Accelerations = reassuring (accelerations + contractions = healthy fetus)
- Absence of accelerations alongside otherwise normal CTG = uncertain significance
What are Decelerations on a CTG?
Decelerations:
- Decelerations = abrupt ↓ in baseline fetal HR of > 15 BPM for > 15 seconds
- Fetus ↓ HR in response to hypoxic stress to preserve myocardial oxygenatiaon (as it can’t ↑ RR)
What are Early decelerations?
Early deceleration:
- Physiologically normal
- Start when a uterine contraction begins and ends when contraction stops
- Contraction –> ↑ fetal ICP –> ↑ vagal tone –> ↓ HR
What is a Variable deceleration?
Variable deceleration:
- ↓ fetal HR with variable recovery phase - may not have any relationship with uterine contractions
- Often seen in labour with ↓ amniotic fluid vol.
- Caused by cord compression
- Accelerations before & after variable decelerations are called ‘shoulders of deceleration’ = reasurring as fetus is not yet hypoxic
What is a Late deceleration?
Late deceleration:
- Begin at peak of uterine contraction & recover after it ends
- Late = insufficient blood flow to uterus / placenta –> fetal hypoxia & acidosis
- Caused by:
- Maternal hypotension
- Pre-eclampsia
- Uterine hyperstimulation
What is a Prolonged deceleration?
Prolonged deceleration:
- Deceleration lasting > 3-mins
- Non-reassuring = deceleration lasting 2-3 mins
- Abnormal = > 3-mins
What are the risks posed by forceps delivery compared to vacuum extraction?
Vacuum extraction compared with forceps is:
- More likely to fail delivery with the selected instrument
- More likely to be associated with cephalhaematoma
- More likely to be associated with retinal haemorrhage
- More likely to be associated with maternal worries about baby
- Less likely to be associated with significant maternal perineal and vaginal trauma
- No more likely to be associated with delivery by caesarean section
- No more likely to be associated with low 5-minute Apgar scores
- No more likely to be associated with the need for phototherapy
In what position is operative vaginal delivery with forceps done?
Lithotomy
When should operative vaginal delivery be abandoned?
OVD should be abandoned if:
- No evidence of progressive descent with moderate traction during each contraction
- Delivery is not imminent following three contractions of a correctly applied instrument by an experienced operator
What factors are associated with ↑ rate of failure of operative vaginal delivery?
- Maternal BMI > 30
- EFW > 4000 g or ‘clinically big baby’
- OP position
- Mid-cavity delivery
- When 1/5th of the head palpable per abdomen
What are the complications of C-section in the 2nd stage of labour?
Maternal:
- uterine/cervical/high vaginal injury
- PPH
- blood transfusion
- sepsis
- admission to ICU
- ↑ length of stay
Fetal:
- admission to neonatal ICU
What is a Fetal Pillow?
A Fetal Pillow = baloon device inserted PV to gently lift baby’s head out from the pelvis during C-section
- Makes delivery easier and safer to perform
- ↓ the risks of complications for mother & baby
What is Malpresentation?
Malpresentation = any non-vertex presentation
e.g. face, brow, breech (buttocks first), or another part of the body if the body is lying in the transverse or oblique position
What are some risk factors for malpresentation?
- Prematurity
- Multiple pregnancy
- Abnormalities of uterus e.g. fibroids
- Partial septate uterus (see pic)
- Abnormal fetus
- Placenta praevia
What is fetal station?
Station = the relationship of the presenting part (head/buttocks/feet) to the ischial spines (assessed vaginally)
measured in centimetres above (-) or below (+) the ischial spines
- For instrumental delivery the leading edge of the fetal skull should be below the ischial spines
Why must position of baby be known prior to operational vaginal delivery?
It is required for positioning of both forceps blades and ventouse vacuum
Not knowing the position prior to use of delivery instruments is dangerous
How is position of baby assessed?
- Using one finger, locate the sagital suture
- Run your finger around in a circle from the sagital suture
- If you can feel 3 sutures it must be the posterior fontanelle
- If you can feel 4 sutures it must be the anterior fontanelle
What is Moulding in pregnancy?
Moulding refers to the bones of the fetal head moving closer and potentially overlapping to help the head fit through the pelvis
- Up to 2+ occipito-parietal moulding may be normal in late labour
- No moulding = parietal bones (sagital suture) are not apposed
- +1 moulding = parietal bones are touching but not overlapping
-
+2 moulding = parietal bones are overlapped but easily reduced
- Need to exclude cephalo-pelvic disproportion
-
+3 moulding = parietal bones have overlapped and are irreducible
- Can be sign a C-section is more appropriate due to cephalo-pelvic disproportion
