instrumentals Flashcards
how to manage a subgaleal haemorrhage ?
it is a medical emergency
Immediate discussion with a neonatologist
a. Stabilisation should not be delayed by any attempts to confirm the diagnosis with
imaging.
b. Aggressive resuscitation to restore circulating blood volume, provide circulatory support,
correct acidosis and to correct coagulopathy is the mainstay of management.
c. Head wrapping may be difficult to perform, and does not appear to be of benefit.
d. Frequent re-evaluation of haemodynamic stability and response to blood and blood products if necessary
What are the levels for monitoring the neonatal for a subgaleal after an instrumental?
Level 1
all instrumentals
Baseline obs, avoid hats, monitor behaviour
Level 2
Risks for SGH - difficult delivery, more then 3 pulls, more then 2 pop offs, suction over 20 minutes
5 minute APGAR <5 - concern at level 1
Cord gases
formal obs for 12 hours
monitor head
level 3
Subgaleal suspected - paeds review
Risk of a subgaleal with different instruments?
What are other risk factors?
Vaccum OR 7.17
Forceps 2.66
Nullip 5 minute APGAR <7 Cup marks on the sagittal suture leading edge of cup closer then 3 cm from anterior fontanelle failed ventouse
difficult delivery with pop offs, prolonged suction or excessive number of strength
What is the technique to avoid a subgaleal?
Cup placement should be:
i. Placed evenly across the sagittal suture, rather than being applied to one or other
parietal bone to avoid asynclitism with traction.
ii. The edge of the cup should be placed at least 3 cm from the anterior fontanelle to
avoid extension of the fetal head during traction (assuming a standard 6cm
cup is being used).
iii. Appropriate cup placement may be impossible if there is significant deflexion or
asynclitism of the head and a “large soft-stemmed” device is being used,
because it cannot be placed sufficiently posteriorly
Traction should be steady, applied only with contractions and only with maternal effort.
c. Adequate descent should be verified (with the non-pulling hand) during each pull.
d. Traction should not be unduly prolonged
Contraindications for ventouse?
Under 34 weeks
34-36 is a relative contraindication
Suspected bleeding disorders eg thrombocytopenia or haemophilia
Osteogenesis imperfect as increased risk skull fracture
Incidence SGH
All deliveries
forceps
ventouse
All deliveries 0.6/1000
Vaccum 4.6-5.9/1000
60-90 % of SGH are from ventouse
Signs of SGH
The initial localised signs of a SGH are of vague, generalised scalp swelling and a laxity of the
scalp, most commonly seen at the site of cup application following vacuum assisted birth. As further
haemorrhage accumulates, the lesion becomes fluctuant; the sensation on palpation having been
likened to ‘an old leather pouch filled with fluid’. A ballotable lesion that crosses the suture lines
should alert the carer to the possibility of a SGH, as should the presence of ‘pitting oedema’
extending over the head, and in front of the ears. The fluid is gravity dependent, and will shift to the
dependent side as the infant is repositioned. Crepitus, or a fluid ‘thrill’, may be noted, this
sometimes being described as a “flick test”.
With progressive haemorrhage, elevation and displacement of the ear lobes, and puffiness of the
eyelids (peri-auricular and periorbital oedema) follows
Generalised signs of a SGH relate to blood loss
5-minute Apgar score < 7, without evidence of
asphyxia; particularly if delivery was affected by prolonged or complicated vacuum extraction.
Irritable cry
Later signs relating to haemodynamic instability include tachycardia, tachypnoea, poor activity and
pallor, anaemia, coagulopathy, hypotension, acidosis and death
Anatomy
Where does the epicranial aponeurosis attach>
The epicranial aponeurosis is a sheet of fibrous tissue covering the entire cranial vault, extending
from the orbital ridges to the nape of the neck and laterally to the ears. Separation of the
epicranial aponeurosis from the underlying periosteum thus creates a compartment large enough
that approximately 250 ml of blood could be accommodated, with only a 1 cm increase in scalp
thickness.
How much blood fits in the subgaleal space?
250 ml of blood could be accommodated, with only a 1 cm increase in scalp
thickness.1
Due to this large capacity, some infants can lose 50-75% of their blood volume into the
subaponeurotic space, resulting in hypovolaemic shock, anaemia, coagulopathy and death.
Among babies admitted to NICU with SGH, neonatal mortality ranges from 12%2
to 25%.
What is the risk reduction of OASIS in primips performing a episitotomy for forceps and ventouse?
he evidence shows that performing an episiotomy in women having their first vaginal birth led to 24% fewer OASI when forceps were used and 16% fewer OASI when ventouse was used and
therefore should be considered.
What many babies are born with instrumentals?
10 % in NZ
What are the risks of second stage caesareans?
Tears in relation to uterine excision hemorrhage blood transfusion Bladder trauma Requirement for ICU
What is the rate of SVD in future pregnancies after an instrumental
80-90 %
What are non operative measures to reduce instrumental birth?
Continuous midwifery support
upright or lateral positions in second stage
No current evidence that epidurals increase instrumentals especially since lower dose techniques are now used (since about 2005)
Judicious use of oxytocin - second stage synto in a woman with an epidural reduces the need for instrumental - care in a multip!
In a primip with a epidural if no urge to push, then delaying for 2 hours decreases the midcavity or rotational instrumental
Manual removal reduces the need for caesarean and increases the rate of vaginal birth
Why is second stage dangerous for babies?
Greatest time of potential compromise is a few hours before birth
fetal descent may precipitate cord compression
Uterine activity + maternal effort reduces placental blood flow
What are the risks of a prolonged second stage?
no defined time
Increased chance of fetal compromise with prolonged pushing
or when the presenting part is low on the perineum for an extended length of time
- consider scalp clip
Maternal exhaustion affects progress
Pelvic floor injury and sphincter dysfunction is more common with increasing duration of second stage
What conditions may prevent a mother from pushing?
Cerebral aneurysm Risk of aortic dissection proliferative retinopathy severe HTN cardiac failure
Can use elective epidural and instrumental
Fetal contraindications to instrumental births
Bleeding disorders
Predisposition to fractures eg osteogenesis imperfecta
relative contraindications
Ventouse contraindicated before 34 weeks
34-36 weeks is a relative contraindication
consider fetal condition
if has had hypoxic insult already more likely to have a instrumental complication - may still be the safest
What are the prerequisites for a instrumental?
Examination 0-1/5 palpable abdominally vertex fully dilated and ROM Exact position of head determined - USS can help Assessment caput and moulding Pelvis deemed clinically adequate
Preparation of mother clear explanation and consent obtained Analgesia in place and effective midcavity rotational delivery should have a regional pudendal if urgent empty bladder IDC removed / balloon deflated aseptic technique
Preparation of staff operator skill adequate equipment Back up plan in place anticipate problems that may arise neonatal resus personnel
What are the classifications for instrumental births?
Outlet Scalp visible without parting labia On the pelvic floor At or on perineum Sagittal suture is anterior - posterior or R / L less then 45 degrees
Low Skull is +2 or more and not on the pelvic floor - less then 45 degrees rotation from OA - More then 45 degrees from OT
Mid 1/5 head spines to +2 - less then 45 degrees rotation from OA - More then 45 degrees from OT
high
above spines or 2/5 - not recommended
What are the highest risk factors for instrumental failure?
BMI over 30
BW over 4 kg
OP
Midcavity or 1/5 head palpable abdominally
what increases the risk in the instrumental of an OASIS
Primip
OP
increasing Fetal weight
What is the OR for an OASIS with a episiotomy with a ventouse in a primip?
Whats the NNT
OR 0.53
NNT 18
What is the success rate for a normal birth with a successful manual rotation?
75-90%
Reduction in caesarean
increase in NVD and instrumentals
What are factors that manual rotation wont work?
Nullip
FTP already evident
Before fully
What are the contraindications to a ventouse
Before 34 weeks 34-36 relative contraindication Face presentation Fetal bleeding disorders Skeletal disorders (osteogenesis imperfecta) Relative - prior FBS
What is the cup placement goals for ventouse?
On the flexion point Midpoint of cup 6 cm from anterior fontanelle - at least 3 cm from posterior fontanelle Midline over sagittal suture Enables flexion avoid rocking
Soft cup 24% failure, 13 % scalp injuries
Rigid cup 10% failure, 24% scalp injuries
Procedure for a safe cup placement (once cup on)
Suction 500-600 mm Hg
traction should be steady, only with contractions, and with maternal effort
Direction should follow pelvic curve
Descent should be verified with each pull using free hand
No consensus about safe number of pulls or time
Upper limit 20 minutes - but by 15 should be imminent
More pulls are ok esp if on perineum and avoiding epis
May say 3 pulls
Cup detachments - 3 would be considered upper limit but application should depend on progress
what is suggested guidance for rotational birth
Adequate station
adequate analgesia
adequate experience
rotate with the uterus relaxed
Low threshold to abandon if forceps cant be applied handles dont lock lack of descent if complicating factors - moulding, macrosomic - should do in OT
What are the fetal risks of an instrumental?
Fetal Shoulder dystocia Subaponeurotic / subgaleal haemorrhage 1/300 Facial nerve palsy Retinal haemorrhage with vaccum Corneal abrasion and facial nerve palsy with forceps Skull fracture / intracranial haemorrhage Forceps 1 in 664 Ventouse 1: 860 LSCS intrapartum 1:900 Spnt NVD 1:2000 Pre labour LSCS 1:2700 Cervical spine injury In a rotational delivery 0.7:1000 (minimised by ensuring uterine relaxation)
Maternal complications of an instrumental ?
Vagina trauma PPH Urinary tract injury OASIS Damage to pelvic floor
Instrumental births
forceps vs ventouse
What are the risks and RR
Cochrane review about vaginal births:
Forceps: Less likely to fail RR 0.65 Fewer cephalohaematomas RR 0.64 Fewer retinal haermorrhages RR 0.6 Fewer cases neonatal jaundice RR 0.79 Fewer cases shoulder dystocia RR 0.4
Higher ¾ degree tears RR 1.9
More birth trauma RR 2.5
Higher incontinence / altered continence RR 1.8
How does MOD correlate with faecal / urinary incontinence?
at 12 years
NVD faecal 11% Urinary 55%
LSCS faecal 10% Urinary 40%
Forceps faecal 17% Urinary 50%
Ventouse faecal 11% Urinary 56%
How often do instrumentals fail?
30% ventouse and 40% rotational deliveries
LSCS after instumental
Risks
Maternal morbidity PPH Transfusion Lower segment tear cystotomy hysterectomy
Neonatal morbidity
Acidosis
Intracranial haemorrhage
Need for resuscitation
Should we give prophylactic antibiotics?
ANODE trial IV Augmentin within 6 hours of delivery Particularly if had an episiotomy or perineal injury 11% infection compared to 19% RR 0.58 NNT 13 Absolute risk reduction 8%
Post natal care for instrumental?
hromboprophylaxis
Risk assessed
Risk factors for VTE often have in common with instrumental – prolonged labour, BMI >30, PET, PPH >1000 mls
Analgesia
Simple paracetamol and NSAIDS are good
Voiding dysfunction
RCOG recommends 12 hours with an IDC if spinal or epidural top up given
Careful monitoring of voiding function
Pelvic floor rehab
PT led pelvic floor exercises reduces urinary incontinence in woman who had an instrumental (or a baby over 4 kg)
Topics for debrief post instrumental
Reasons for operative birth
Management of complications
Prognosis for future pregnancies
Associated with fear of subsequent birth
In woman who delivered in second stage in theatre (LSCS or instrument) 32% want to avoid pregnancy and half for fear of childbirth
