Presentation on theme: "Shoulder Dystocia Review July 24, 2014"— Presentation transcript:
1Shoulder Dystocia Review July 24, 2014 Marie-Claude LaplantePaula TchenMS3
2ObjectivesPropose & execute immediate management of shoulder Dystocia.Describe options if immediate management of shoulder Dystocia is not successful.
3DefinitionAbnormal labour or dystocia (means difficult labour or childbirth)Occasionally referred to as failure to progress.A vaginal delivery is complicated by shoulder dystocia when, after delivery of the fetal head, additional obstetric maneuvers beyond gentle traction are needed to enable delivery of the fetal shoulders.*leading indication for primary C/S in the USvariability in the diagnosis, management and criteria for dystociaRarely diagnosed with certainty
4Pathophysiology of shoulder dystocia During delivery the anterior shoulder should slide under the symphysis pubis. If the fetal shoulders remain in an anterior- posterior position during descent or descend simultaneously rather than sequentially into the pelvic inlet, then the anterior shoulder can become impacted behind the symphysis pubis; the posterior shoulder may be obstructed by the sacral promontory. Anterior obstruction is more common than posterior obstruction. If descent of the fetal head continues while the anterior or posterior shoulder remains impacted, then stretching of the nerves in the brachial plexus may occur and may result in nerve injury.If fetal head is turned to one side (asynclitism) or extended (extension) the cephalic diameter is increased. Brow presentation can cause dystocia if it does not convert to vertex or face.
5Epidemiology of shoulder dystocia .2-3% of all birthsCan you predict a shoulder dystocia?NO! most often cannot predict and occur in the absence of risk factors.
6Factors that contribute to normal labour What are the factors that contribute to normal labour?PowerPassengerPositionPassage: maternal factors: shape of pelvis or soft tissue abnormalities.Clinical radiographic and CT measurements of the pelvis are poor predictors and inaccurateSoft tissue causes: morbid obesity, distended bladder, fibroids, accessory uterine horn, lesions of colon or adnexa, abnormalities of cervix, tumors. Epidural will decrease tone of pelvic floor and can contribute to dystociaIneffective uterine contractions will contribute to dystocia- monitor with tocometry
7Risk Factors Increased fetal birthweight Increased risk with weight over 4000g. Macrosomia is >4500g. With increasing weight, risk will increase.Post-term, excessive weight gain during pregnancy>35lbs, parityDiabetesMidforceps deliveryProlonged first/second stage?Prior shoulder dystociaMaternal height: more risk among shorter parturients <150cmMore permanent injuries occur among macrosomic infants but the majority of shoulder dystocias occur with infants of normal weight
8Diagnosis Head to body delivery time exceeding 60s Friedman’s curve to assess labourAbnormal labour patterns:1)prolonged latent phase; more than 20 hours in nulliparous or 14h in multiparous.2)active labour: cervix dilates less than 1cm/hour nulliparous or less than cm/hour multiparous
9Management Reduction maneuvers – HELPERR Mnemonic Call for Help Evaluate for EpisiotomyLegs (McRoberts Maneuver)Suprapubic PressureEnter maneuvers (internal rotation)Removal of the posterior armRoll the patientEpisiotomy: Consider when dystocia is encountered – episiotomy won’t release the bony impaction, but it helps to increase room for physicians as they do internal maneuvers.McRoberts: Ideal first step, proven effectiveness – rotates the symphysis and flattens the sacral promontory. If successful, the delivery should work with simple traction.Suprapubic pressure: accentuates the passage of the shoulder under the symphysis – should be done with McRoberts.Enter maneuvers: May require episiotomy. Rubin II = rotate anterior shoulder towards foetus chest. If unsuccesful, do Woods corkscrew (upward pressure on anterior aspect of posterior shoulder). Always continue traction during maneuversRemoval of the posterior arm: find arm, flex elbow, sweep on chest wall and deliver it. If you can’t reach the elxbow you can also grasp the axilla.Roll patient: Rolling pt on all fours (Gaskin maneuver) is safe and rapid as helps reduce shoulder dystocia by increasing the pelvic diameter
12Management Reduction maneuvers – HELPERR Mnemonic What we’re trying to accomplish:Increase functional size of the bony pelvisDecrease the bisacromial diameter (breadth of the shoulders)Change the relationship of the bisacromial diameter within the bony pelvis
14Management If those maneuvers fail: Last resort: Deliberate clavicule fractureZavanelli maneuverGeneral anesthesiaCesarian sectionSymphysiotomyClavicule fracture: reduces shoulder-to-shoulder distanceZavanelli maneuver: cephalic replacement followed by cesarean delivery – essentially you put the baby back in and go to the ORGA: May bring enough uterine relaxation to help deliveryAbdominal surgery with hysterotomy: cesarian section (foetus is rotated transabdominally)Symphysiotomy: LAST RESORT, not really used here, only when all other maneuvers have failed and c-section isn’t available
15Prophylactic management Typically, you can’t predict, so you can’t prevent!(ACOG) Task Force on Neonatal Brachial Plexus Palsy clinical situations as high risk for shoulder dystocia and brachial plexus injury:Estimated fetal weight >5000 g in women without diabetes or >4500 g in women with diabetesPrior shoulder dystocia, especially with a severe neonatal injuryMidpelvic operative vaginal delivery of a fetus with estimated weight >4000 g*Cesarean section is a reasonable option for these patients, but is discussed as a case by case basis.Estimated weight: difficult to evaluate- Induction not recommended for estimated high birth weight – studies show it doesn’t prevent shoulder dystocia in comparison to expectant managementPrior dystocia: uptodate suggests a c-section, but there are no official guidelines or studies to show the overall outcome. Factors such as high estimated birth weight and gestational diabetes should be taken into account, but basically this is a perfect example of shared decision making.
16Complications Remember: diagnosis and timing are key Why? Avoid complications:Fetal:AsphyxiaCortical injury due to cord compression and asphyxiaTransient/permanent brachial plexus palsyClavicular or humeral fractureDeathMaternal:HemorrhageFourth degree lacerationsCord pH drops with increasing head-to-body-interval, but the drop does not become clinically significant for about 5 minutes.[15, 16] A 6-minute head-to-body interval has been demonstrated not to be a risk factor for hypoxic ischemic encephalopathy (HIE). Beyond that time, there is increased risk of neonatal depression, acidosis, asphyxia, central nervous system damage, and death.[18, 19, 20]
17Clinical case: Shoulder dystocia A 30 yo G2P1 is delivering at 41 weeks gestation. She is moderately obese, but the fetus appears to clinically weigh approximately 3700 g. After a 4-hour first stage of labor and 2- hr second stage of labor, the fetal head delivers but is noted to then retract back toward the patient’s introitus (turtle sign). The fetal shoulders do not deliver, despite strong maternal pushing.DiagnosisRisk FactorsManagement Principles of this Obstetric Emergency/ Initial Maneuvers to manage this conditionReview Neonatal and Maternal Complications of this eventDiscussion point fetal weight (passenger) estimation is inaccurate. If weight is greater than g the risk of dystocia including shoulder dystocia and fetopelvic disproportion is greater. Fetal macrosomia defined as birthweight over 4500g(ACOG)2 hour second stage- for multiparas we limit to one hour or 2 hours with regional analgesia- for nulliparas limit to 2 h or 3 h with regional analgesiaRates of chorioamnionitis, PPH, instrumental delivery, Cesarean section and perineal trauma increase with increasing length of the active second stage of labour.What is significance of turtle sign? May herald shoulder dystociaRisk factors in this case : maternal obesity, pelvis- anatomy unknown. No prior history of dystocia in this case. No history of diabetes. Mother’s height unknown.
18Case discussionfetal weight (passenger) estimation is inaccurate. If weight is greater than g the risk of dystocia including shoulder dystocia and fetopelvic disproportion is greater. Fetal macrosomia defined as birthweight over 4500g(ACOG)2 hour second stage- for multiparas we limit to one hour or 2 hours with regional analgesia- for nulliparas limit to 2 h or 3 h with regional analgesiaRates of chorioamnionitis, PPH, instrumental delivery, Cesarean section and perineal trauma increase with increasing length of the active second stage of labour.What is significance of turtle sign? May herald shoulder dystociaRisk factors in this case : maternal obesity, pelvis ?- anatomy unknown (mother is G2 but first baby premature). No prior history of dystocia in this case. No history of diabetes. Mother’s height unknown.
19ReferencesBaxley, E; Gobbo, R. Shoulder Dystocia 2004 American Family Physican, 69(7), pBeckmann et al. Obstetrics and Gynecology. 7th edition Lippincottt Williams & Williams.Uptodate.com