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SECOND EDITION OF THE ALARM INTERNATIONAL PROGRAM SYLLABUS

CHAPTER 9

SHOULDER DYSTOCIA

Learning Objectives: Use a systematic approach to the reduction of shoulder dystocia based upon the physical mechanisms of

impact and disimpaction

A 23 year old primip is induced at 41 and a half weeks with vaginal prostagladins. The first stage was uneventful. You were asked to assess her after 2.5 hours in the second stage as there seemed to be no further descent of the fetal head. Examination confirms that the head is on the pelvic floor in an OA position. Caput is visible at the introitus with contractions. The fetal heart is normal the patient is clearly exhausted. She readily accepts your suggestion regarding the use of a vacuum to effect delivery. What are the problems that may be encountered at this point?__________________________________________________________________________________________________________________________________________________________________________________________

Following an easy application, there is moderately good descent during the first pull but this slows down as the head is half out. What are potential causes for this and what is your plan of action at this point?__________________________________________________________________________________________________________________________________________________________________________________________

Shoulder dystocia is confirmed. What is your management?__________________________________________________________________________________________________________________________________________________________________________________________

Delivery is accomplished. Now what?__________________________________________________________________________________________________________________________________________________________________________________________

9.0.1 Definition and Classification

1) Definition:

Impaction of anterior shoulder above symphysis Inability to deliver shoulders by usual methods

Following the delivery of the head, there is impaction of the anterior shoulder on the symphysis pubis in the AP diameter, in such a way that the remainder of the body cannot be delivered in the usual manner. The head may be tight against the maternal buttocks, known as the "turtle sign". Spontaneous restitution may fail to occur.

2) Classification:

Incidence

Incidence ranges from 1 in 1,000 for babies weighing less than 3,500g, to over 16 in 1,000 in babies over 4,000g. Despite numerous studies attempting to identify factors predicting this problem, more than 50% of cases occur in the absence of any identified risk factor.

ALARM INTERNATIONAL * Chapter 9 - Shoulder Dystocia* 111


Significance

Complications of shoulder dystocia include: Fetal/neonatal

death hypoxia/asphyxia and sequelae birth injuries

fractures – clavicle, humerus brachial plexus palsy

Maternal postpartum hemorrhage

uterine atony maternal lacerations

uterine rupture

Fractures of the clavicle and humerus can occur even during appropriate management. These in fact are preferable to fetal asphyxia.

Brachial plexus injury is most commonly caused by extreme lateral traction on the fetal head. Nerve root damage usually involves the origins at the C5 and C6 level. These nerve roots supply the forearm flexors and supinators. Thus the arm is extended and pronated resulting in the classical Erb-Duchenne palsy. This brachial plexus injury is of varying degree and fortunately, rarely results in permanent damage.

Risk Factors

Post-term pregnancy Maternal obesity Fetal macrosomia Previous shoulder dystocia Operative vaginal delivery Prolonged labor Poorly controlled diabetes

Although many assume that diabetes is the major risk factor for shoulder dystocia, it is unlikely to be a factor unless it is poorly controlled and associated with maternal obesity. Maternal obesity and post-term pregnancy are the factors most commonly present in cases of shoulder dystocia.

9.0.2 Diagnosis and Management

1) Diagnosis

Head recoils against perineum, ‘turtle’ sign


Fetal asphyxia secondary to cord compression may result in permanent neurologic damage and even death. In the fetal monkey model the fetal pH drops by 0.04/min when the cord is totally occluded. If all has been well up to that time, then even after total occlusion for 7 minutes, the pH will have only dropped by 0.28. In shoulder dystocia, unless the cord has been clamped and divided, there is likely some preservation of maternal-fetal circulation and therefore less risk of fetal hypoxia.


Spontaneous restitution does not occur Failure to deliver with expulsive effort and usual gentle downward direction Identified risk factors are present in less than 50% of cases

2) Management

Given our inability to predict the occurrence of shoulder dystocia reliably, every delivery should be seen as having the potential to result in shoulder dystocia. Therefore, a management protocol must be in place and well known to all caregivers. The ALARM mnemonic has been developed to assist in the appropriate and consistent management of this common complication.

A Ask for helpL Lift/hyperflex Legs A Anterior shoulder disimpaction R Rotation of the posterior shoulderM Manual removal posterior arm

Shoulder dystocia is not a maternal soft tissue problem. However, episiotomy may facilitate the performance of the above manoeuvres, by allowing for additional access. One may consider the following addition to the mnemonic.

E EpisiotomyR Roll over onto ‘all fours’

Ask for help

Set up for obstetric emergencies Get the co-operation of the mother, partner, coach, etc. Establish and practice a nursing protocol Notify your physician backup, and enlist other appropriate personnel

Lift the Legs

Hyperflex both legs (McRobert's manoeuver) Shoulder dystocia is resolved in 70% of cases by this manoeuver alone

Anterior disimpaction

Abdominal approach - suprapubic pressure applied with the heel of clasped hands from the posterior aspect of the anterior shoulder to dislodge it (Mazzanti manoeuvre)

Vaginal approach - adduction of the anterior shoulder by pressure applied to the posterior aspect of the shoulder (i.e. the shoulder is pushed towards the chest)

This results in the smallest possible diameter (Rubin manoeuvre)

Rotation of the posterior shoulder

Woods’ screw manoeuvre is a screw-like manoeuver. Pressure is applied to the anterior aspect of the posterior shoulder, and an attempt is made to rotate that shoulder 180° to the anterior position. Success of this manoeuvre allows easy deliver of that shoulder.

In practice, the anterior disimpaction manoeuver and Woods’ manoeuver may be done simultaneously and repetitively to achieve disimpaction of the anterior shoulder.



Manual removal of the posterior arm

The arm is usually flexed at the elbow. If it is not, pressure in the antecubital fossa can assist with flexion. The hand is grasped, swept across the chest and delivered.

Finally, if unsuccessful in repeated attempts or if unable to gain access:

Episiotomy is an option that may facilitate the Woods’ manoeuvre or manual removal of the posterior arm.

Roll over to knee chest positionSome British midwifery texts advocate this manoeuvre, as it appears to allow easier access to the posterior shoulder. Prior experience with delivery in this position would be an asset.

Avoid the 4 P's.

DO NOT! 1. Pull2. Push3. Panic4. Pivot (i.e. severely angulating the head, using the coccyx as a fulcrum)

If nothing has worked to this point and all the procedures have been tried again, then some have suggested:1. Deliberate fracture of the clavicle or humerus2. Symphysiotomy3. Zavenelli manoeuver (cephalic replacement) - reversing the cardinal movements of labour

rotate head to OA, flex, push up, rotate to transverse, disengage and perform a cesarean section

AFTER SHOULDER DYSTOCIA

1. Remember the SIGNIFICANT risk of maternal injury (tears) and postpartum hemorrhage. Actively manage the third stage. Inspect for and repair lacerations.

2. Ensure appropriate neonatal resuscitation and assessment. Examine for trauma.3. Shoulder dystocia must be documented appropriately in the chart and the manoeuvers that were done must be

described completely.4. Explain to the woman and all those involved in the delivery exactly what occurred and what management steps

were taken.

9.0.3 Summary:

1. Be prepared. Develop and practice a standard management protocol. The ALARM mnemonic may be helpful.2. Don’t panic.3. Remember the ongoing care including a clear explanation to the parents and documentation.


5. Do cord blood gases


Suggested Readings1. Rubin A. Management of shoulder dystocia. JAMA 1964; 189: 835-72. Woods, CE. A principle of physics as applicable to shoulder delivery. AJOG 1943; 45:796-8043. Jennett RJ, Tarby TJ, Kreinick CJ. Brachial plexus palsy: an old problem revisited. AJOG 1992: 166: 1673-74. Gherman RB, Ouzounian JG, Goodwin TM. Obstetric maneuvers for shoulder dystocia and associated fetal morbidity.

AJOG 1998, 178:1126-30.5. Mastrogiannis DS., Knuppel RA. Critical management of the very low birth weight infant and macrosomic fetus. Clin

Perinatol. 1996 23: 51-896. Baskett TF. Essential Management of Obstetric Emergencies. Clinical Press Limited. 1999. Third Edition.

pp.130-5



ALARM MNEMONIC

A ASK for help

L LIFT / hyperflex Legs

A ANTERIOR shoulder disimpaction

R ROTATION

M MANUAL removal posterior arm


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