Transcript Shoulder Dystocia

Shoulder Dystocia
Prediction and Management
Outline
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Introduction/Definition
Incidence
Aetiology / Risk Factors
Prediction
Management/ Prevention
Complications / Litigation
Controversies
Introduction
• A serious frightening and threatening
obstetric emergency.
• It’s a situation where if undue haste is not
balanced with delay, a delivery which
would have been a normal happy event
becomes catastrophic.
Definition
• Shoulder dystocia has no universally
accepted definition.
• It occurs when the shoulders fail to
traverse the pelvis after delivery of the
head (Smeltzer 1986).
• Resnik defined “True Shoulder Dystocia as
deliveries requiring in addition to the usual
downward traction and episiotomy,
manouvres to deliver the Shoulders”.
• Sponge et al found a mean head-to-body
delivery time of 24seconds in normal
babies compared with 79 seconds in those
with shoulder dystocia and therefore
proposed that any head-to-body delivery
time greater than 60 seconds should be
regarded as shoulder dystocia
INCIDENCE
• Incidence figures varies according to the
definition used.
• It varies between 0.37%-1.1% of all deliveries
• With the definition of true shoulder dystocia it
can be as low as 0.23%.(Beneditti et al).
- Incidence is generally on the increase due to
increasing birthweight, improved perinatal care,
better reporting and documentation
• Experience of the accoucher and position
assumed by the patient during delivery also
affects the incidence
AETIOLOGY /RISK FACTORS
• Basically the aetiology of shoulder
dystocia are-:
• A disproportion between the fetal chest
and maternal pelvis. Kwawukwame 2000
• Malrotation of the fetal shoulder at the
pelvic inlet
• A maternal pelvis flattened anteroposteriorly or a platypelloid pelvis
•In normal delivery the movement of the
shoulders aids its passage through the birth
canal since the bisacromial diameter is wider
than the biparietal diameter
•Big fetuses require an initial further rotation
towards the transverse direction for the
shoulders to enter the pelvis
•Failure of this rotation leads to persistence of
the antero-posterior position of the shoulders at
the brim
•Hence impaction of the shoulders
RISK FACTORS
MATERNAL FACTORS
• Obesity: Macrosomia is common among
obese women by its effect on fetal weight
and increased incidence of gestational
diabetes. Mothers weighing >81kg
experienced 30% of all S.D (Seigworth
1966)
• Diabetes mellitus: The macrosomia of
IDDM is characterised by selective
organomegaly. Greater Shoulder/Head1,
Chest/Head2, Abdomen/Head3 ratios cf
babies of similar weight of non-diabetic
mothers.(Mondalou et al1,Delpapa et
al2,Cohen et al3 ).
• Prolonged pregnancy-:Eden et al found
incidence of S.D at 40weeks to be 0.7%
rising to 1.3% at >/= 42weeks.A no of
fetuses particularly males have been
known to continue growing exceeding 4kg
after 42 weeks gestation.
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Previous shoulder dystocia-: recurrent
risk of 9.8-13.8%
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Short maternal stature-(less than 1.5m),
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Advanced maternal age and Multiparity.
FETAL FACTORS
• Weight-:incidence of S.D is proportional to the
birth weight
• S.D is 11 and 22 times more common in babies
weighing more than 4000g and 4500g
respectively (Acker et al 1985)
• Incidence of 5.2% in 4000g-4250g and 21% for
4750g-5000g in non-diabetics,
• 8.4%and 23.5% for similar weight in diabetic
women was found by Nesbitt et al (1998)
• INTRAPARTUM RISK FACTORS
• Vacuum extraction and forceps delivery especially in the
midcavity for prolonged second stage (Sokol et al 2002)
• Arrest disorders
• Primary dysfunctional labour
• Epidural anaesthesia- controversial.
PREDICTION
• Most risk factors are poor predictors of S.D and
only about 25% of cases exhibit at least one
significant risk factor (Gherman et al)
• Fifty to sixty percent of S.D occurred in infants
who weighed less than 4000g.
• Gonen et al(1996),using a combination of
clinical(sensitivity-20%) and sonographic(error-+/-12%) data found poor correlation between
prenatal estimation of birth weight and actual
birth weight.
• However, a rate of fetal abdominal growth
>1.2cm/wk between 32-39wks is
predictive.
• Macrosomia index: chest/biparietal
diameter of 1.4 or more.
MANAGEMENT
• “Turtle neck sign” where there is failure of
restitution and the neck is not visible and
baby’s face appears fat may be the first
warning sign of impending danger.
• Decreasing the time interval between
delivery of the fetal head to body is of
great importance to baby’s survival.
• Resist pulling on baby’s head
• Don’t apply fundal pressure
• Don’t cause excessive rotation of the fetal
head
• Left lateral positioning may overcome mild
S.D. This may be difficult for the patient.
• “Shoulder dystocia drill” sequence
depends on the experience of the operator
and the help available.
HELPER mnemonic
• H-:call for help (senior obstetrician, midwife, paediatrician, anaesthetist)
• E-:episiotomy protects the pelvis, creates
access to pelvis and increases chances of
shoulder delivery.
• L -: legs. Here maternal hips are abducted
flexed and rotated, straightening the
sacrum, and reducing the angle of pelvic
inclination (Mc Roberts manoeuvre)
• P-: pressure, lateral suprapubic pressure
should be applied by an assistant to
dislodge the shoulders from the symphysis
and adducts the shoulders causing
reduction in bisacromial diameter.
• E-:enter manoeuvres .
a. wood’s cockscrew
b.rubin manoeuvre.
c. delivery of the posterior shoulder.
R-: removal of the posterior arm by inserting
operator’s hand in the vagina to cause
flexion of the posterior arm at the shoulder
and the elbow to retrieve the hand or
forehand. This may result in fracture of
clavicle or humerus .
• Cephalic replacement (Zavannelli
manoeuvre): A desperate measure to
replace the fetal head for abdominal
delivery with the use of tocolytics,
correction of restitution, flexion of head
and gradual return into the vagina-followed
by caesarean section
-usually associated with maternal
morbidity e.g ruptured uterus, PPH,
endometritis
Other alternative measures
• Deliberate fracture of the clavicles
• Symphysiotomy
• Cleidotomy
COMPLICATIONS
• MATERNAL
-Genital lacerations
-Postpartum hemorrhage:atonic/traumatic
-Bladder injury
-Fistulae: VVF, RVF
-wound sepsis and dehiscence
-Symphyseal separation/ neuropathy
COMPLICATIONS contd
• NEONATAL
-Mortality: 2 - 29% -Morbidity: 20-25%
-Asphyxia: as evidenced by early neonatal
seizures and permanent central neurological
deficits.
-Brachial plexus injury: In 11.6-16.5%,most
common is Erb’s palsy due to avulsion injury to
C5 & 6 nerve roots (95% usually resolve within
neonatal period). Klumpke’s paralysis due to
injury to C7,C8 nerve roots.
-phrenic nerve palsy leading to paralysis of
the hemidiaphragm
-thoracic spinal cord injury will cause
overflow and rectal incontinence
-sympathetic outflow tract from T1 injury
causes diminished pigmentation of the iris
Bachial plexus injury have better prognosis
than lower root traumas
Skeletal injuries-: fracture of the clavicle
and humerus may occur but both have
excellent prognosis.
PREVENTION
• Pre-conceptional maternal weight
reduction/ diabetic control: Coustan et al
observed a decrease rate of S.D from
20.4% to 13.4% in those on dietary
regimen and to 4.8% in those on insulin
regimen.
• Avoidance of mid-cavity instrumental
delivery for macrosomic infants following a
delayed second stage.
-Elective caesarean section- controversies
-Training and teaching of birth attendants
with regular rehearsals of methods of
dealing with S.D.
RISK OF LITIGATION
S.D poses tremendous risk of litigation to the physician.
Appropriate documentation of
-decisions taken
-procedures employed
-outcome of procedures
-effective communication with the baby’s mother will
go a long way in reducing such risks..
CONTROVERSIES
• Elective caesarean section of macrosomia
• Accuracies of clinical and sonographic
estimates of fetal weight in management’s
decision-making
CONCLUSION
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A life threatening obstetric emergency
High index of suspicion
Call for help
Above there should be a team leader