Instrumental Flashcards
Postnatal care involvement
Analgesia Voiding function Bowel function Thromboembolic prophylaxis Rehabilitation of the pelvic floor Counselling regarding the birth and future births
Percentage of births
11% aus
10% nz
Likelihood of vaginal birth after one previous
78-91%
Consequences of delays in second stage of labour
Increased chance of fetal compromise with prolonged pushing in second stage, or when the presenting part Is low on the perineum for an extended length of time
Maternal exhaustion
Pelvic floor injury
Relative contraindications and contraindications to instrumental birth
Fetal bleeding disorders
Predispostion to fractures
No vacuum for a face presentation or <34/40
Caution ventouse 34-36
Prerequisites for instrumental vaginal birth
Full abdominal and VE: less than or equal to 1/5 palpable abdominal Ly, head, fully dilated, ROM, position, assess caput and mounding, pelvis adequate
Prep mother: explanation, consent, analgesia, bladder emptied, aseptic technique
Prep staff: operated needs knowledge, experience and skill, adequate facilities, back up plan, anticipate complications, neonatal resus team
Outlet birth
Fetal scalp visible without separating labia
Fetal skull reached the pelvic floor
Sag suture in AP diameter or ROA or LOA or OP (do not exceed rotation >45 degrees)
Fetal head is at or on perineum
Low
Leading point of the skull (not caput) is at station plus 2cm or more and not on the pelvic floor
Rotation of 45 degrees or less from the OA
Rotation of more than 45 degrees including the OP position
Mid
Fetal head is no more than 1/5th palp
Leading point of the skull is above station +2cm but not above the ischial spines
Subdivisions
- rotation of 45 degrees or less from the OA position
- rotation of more than 45 degrees including OP
High
Not included in the classification as instrumental vaginal birth is not recommended in this situation where the head is 2/5th or more palpable abdominal Ly and the presenting part is above the level of the ischial spines
Increased risk of instrumental failure
BMI>30
EFW >4kg
OP
Mid cavity or when 1/5 palp abdominally
Cup placement
Flexion point (6cm from the anterior fontanelle and 3cm from the posterior fontanelle in the midline over the Sagital suture)
Failure rate and scalp injury rates by cups
Failure:
Rigid 9.5
Soft 14.8
Injury
Rigid 24%
Soft 13%
Vacuum suction pressures
500-600mmHg
Establishment of negative pressure without delay reduces procedure time without compromising effectiveness or safety
Rotational forceps risks over caeser
Increased risk of traumatic intracranial haemorrhage and cervical spine injury
Rotational cup risks
Higher failure rate
Increased risk intracranial and subaponeurotic/subgaleal haemorrhage
Complications of instrumental birth (fetal)
Shoulder dystocia Subgaleal haemorrhage Facial nerve palsy Corneal abrasion Retinal haemorrhage Skull fracture ICH Cervical spine injury
Risk of skull fracture and or intracranial haemorrhage by mode of birth
Forceps : 1 in 664 Vacuum: 1 in 860 Caeser (intrapartum): 1 in 907 SVB: 1 in 1900 Cold caeser: 1 in 2750
Maternal complications of instrumental del
Vaginal trauma PPH urinary tract injury Damage to pelvic floor Damage to anal sphincter
Advantage forceps
More likely to achieve vaginal birth Less cephalhaematoma Less fetal retinal haemorrhage Less neonatal jaundice Less shoulder dystocia Less maternal worry
Advantage vacuum
Less OASIS
Less type of any vag trauma
Less incontinence
No significant difference between instruments
Any neonatal injury
Low apgar score (<7) at 5 minutes
Low pH (<7.2) in umbilical artery at birth
Subgaleal haemorrhage
Accumulation of blood in the loose connective tissue of the subgaleal space
Rate of mortality with SGH
12-25%
Risk factors for SGH
Vacuum extraction Incorrect positioning Prolonged extraction time (>20min) >3pulls >2 cup detachments Failed vacuum PROM >12 hours Macrosomia, neonatal coagulopathy LBW male sex
Nulliparity
5 minute apgar <8
Cup marks on sagital suture
Leading edge of cup <3cms from anterior fontanelle
Pathophysiology of SGH
Fractional and rotational forces with the use of vacuum extraction can result in rupture of veins and haemorrrhage into different layers of the scalp.
Most significant - rupture of emissary veins into the subgaleal space
Signs of SGH
Generalized swelling or a boggy consistency of the scalp, not limited by sutures, especially at the cut site
Elevation and displacement of the ear lobes and periorbital oedema
Hypovolemic shock:tachycardia, tachypnoea, dropping haematocrit on blood gases, increasing lactates, worsening acidosis, poor activity, pallor , hypotension, acidosis
Degree of SGH
6% asymptomatic
15-20% mild
40-50% moderate
25-335 severe
Management SGH
Vit K asap Cord ph, lactate, FBC and platelets Admit nicu for Obs Coag Group and cross matched Cap gas Maintain bsls
Indications for operative vaginal delivery
Presumed fetal compromise
To shorten and reduce the effects of the second stage of labour on medical conditions (ie cardiac disease)
Inadequate progress -
-primip: lack of continuing progress for 3 hours (total of active and passive second stage labour) with regional anaesthesia or 2 hours without regional anaesthesia
-multip- lack of progress for 2 hours with anaesthesia or 1 hour without
Maternal exhaustion
