Obstetrics

NNE Rural Emergency Services and Trauma SymposiumNovember 7, 2008

Obstetrics PrinciplesWith rare exception do not omit any care for an injured or seriously ill pregnant woman that you would give her if she was not pregnant.

Pregnant women are generally more healthy/less fragile than the overall population.

If you are not an OB care provider, you have limited responsibility for evaluating fetal status. Ask about fetal movement.

Get OB consultation if your training is TraumaGet Trauma consultation if your training is OB

OB basics

Determine the gestational age Uterus not palpable – first trimesterAbove pelvic brim – second trimesterAt umbilicus – 20 weeksSeveral centimeters above umbilicus – begin viabilityAt costal margin- around term

OB basics

Fetal outcomes<23 weeks: non viable<24 weeks: rarely viable24 weeks 50:5028 weeks 90% survival

<28 weeks avoid delivery unless fetal distress28-32: avoid delivery if possible>32 weeks: less reluctance to delivery

OB basics

Physiology is working overtimeRenal: normal creatinine is <0.9 mg/dlRespiratory: increased ventilation, decreased FRC

normal pCO2 is <34 mmHg (27 – 32 mmHg)normal pH is >7.35 (7.40 – 7.45)maternal SaO2 should be >94%

CV: decrease blood pressure, increased heart rate, increased cardiac output, more tolerant of hemorrhageHeme: mild anemia due to dilution, mild thrombocytopeniaCoag: normal fibrinogen is >>250 mg/dl

Ob basicsGravida = number of pregnanciesPara = numbers of past deliveriesGestational ageFetal presentationLast cervical examinationAssessment of contractions: frequency, subjective intensityLeaking or bleedingFetal activityCondition of mother between contractionsMedicationsGroup B strep status

OB basics

Supine inferior vena cava compressionmaternal cardiac output and uterine blood flow depend strongly on maternal positionhip tilt, wedge, lateral position

Increased risk of aspirationmore conservative choices about airway

Rapid oxygen desaturationsupplemental maternal oxygen also provides oxygen content to the fetus

Response to hemorrhage

Orthostatic changes: 10-20% loss (500-1000 cc)Mild hypotension, HR 100, peripheral vasoconstriction: 20-25% (1000-1500 cc)Moderate hypotension (SBP 80-100), HR 100-120, restlessness: 25-35% (1500-2000 cc)Severe hypotension (SBP<60), HR >120, altered consciousness: > 35% loss (> 2000 cc)

Response to hemorrhage

When hypotension occurs, there is severe intravascular depletion, risk of coagulopathyand shockFurther deterioration can be rapidFetuses tolerate hypotension poorly

Trauma/obstetrics

Take care of the pregnant woman first. Follow standard protocols. Get OB care provider in the communication loop.Maternal positionABC’sOxygenImaging: do what’s needed if acceptable option choose MRI, ultrasoundAll pregnant women will have contractions after trauma, uncommonly triggers premature labor

Blunt trauma

First trimester and early second trimestersplenic ruptureliver contusion and rupturerenal contusionpelvic fracture

Third trimesterBladder injuryUterine ruptureFetal injuryRetroperitoneal hemorrhagePlacental abruption

Penetrating trauma

Upper abdomen injury - bowelHigh fetal mortalityUterus protects abdominal organsOften requires open exploration

Obstetrics emergencies/ indications for transport

Third trimester bleedingPremature laborPremature rupture of membranesPreeclampsia/ eclampsiaPostpartum hemorrhage

Third trimester bleeding

Previa“painless”

Abruption (premature separation)“painful”partial or completeconcealed or external

Uterine ruptureTrauma or labor after cesarean

Fetal bleeding (very rare)“Bloody show” (very common)

Third trimester bleedingPlacenta previa until proven otherwise

No vaginal examinationsIV access: two large peripheral linesLabs: CBC, type and screen, coagsBlood products available if possible(Reassuring fetal monitoring gives evidence of adequate maternal circulation)Preterm labor may be treated at the judgment of obstetrical care providerTransfer decision can be tough; dialog with tertiary care center

Abruption

Etiology: spontaneous, PROM, traumaMore common in severe trauma

1-5% in minor trauma20-50% in severe traumaUsually a deceleration injury not direct trauma

Will usually cause labor

Abruption

Signs and Symptoms:abdominal painuterine contractionsuterine tendernessvaginal bleedingfetal tachycardia or bradycardiaS/S of hypovolemiarising fundal height

Premature labor

Labor prior to 37 weeksHard to diagnose if early, lots of “false positives”Painful, regular uterine contractions (~5-10 min) with cervical change or initial cervical exam of at least 2 cm dilated and 80% effaced or with ruptured membranes

Premature labor

Decisions: stop or don’t stop (made by OB)Gestational ageMembranes intact or rupturedFetal conditionBleedingCervical dilation

Steroids or no steroidsbetamethasone 12 mg IM q 24 hour x 2dexamethasone 6 mg IM q 12 hour x 4

Antibiotics (almost always yes) for GBS

PTL medications

Beta agonists: terbutaline (given sc)NSAID: indomethacin (oral)Calcium channel blocker: nifedipine (IV)Magnesium sulfate (IV)

Nifedipine

No single regimen:Usually start with 10-20 mg load, repeat x 1 in 30 minHold if <90/50 mmHgDon’t give with magnesiumHeadacheMake sure the short acting form is given

Magnesium

Competes for calcium channelLoad 4-6 grams over 20-30 minInfusion 2 -3 grams/hourDose dependent toxicity: lethargy – cardiac arrestANTIDOTE: 10 cc 10% solution of calcium gluconateIf there are DTR’s, level is OKCauses nausea, vomiting, diplopia, weakness

Premature rupture of membranes

Prior to labor, term or pretermRisks: premature labor, abruption, infection, fetal deathNo/minimal digital cervical examinationsTocolysis for transport

Preeclampsia

New onset hypertension and proteinuria140/90At least 1+ urine protein or 300 mg/day

Cure is delivery

Severe preeclampsia

Severe preeclampsia> 160/110 mm/Hg5 grams of proteinuriaPersistent headache or visual disturbancePersistent epigastric painOthers: platelet <100K, AST >70, oliguria

Preeclampsia “crises”

HELLP: hemolysis,elevated liver enzymes, low plateletsSevere hypertensionComa, seizures (eclampsia)DICRenal failureAbruptionLiver rupturePulmonary edema

Preeclampsia medications

Magnesium sulfate for seizure prophylaxisLoad 4 grams over 20-30 minInfusion 2 grams/hour (if any concern for kidney function, just give load and start transfer at level III)

Steroids: betamethasone for fetal lungs, dexamethasone for platelets <50KAntihypertensives: labetolol, hydralazineHave calcium gluconate available (10cc 10% solution)

Preeclampsia

Blood pressures > 170/110 mmHgGoal: 140-160/90-105 mmHgAvoid blood pressures < 130/80 mmHg

Fetal distress due to decreased uterine blood flowInadequate other organ perfusion including brain

Minimize IV fluidsWatch urine output (shouldn’t transport on magnesium without a foley catheter)Check DTR’s

Antihypertensive meds

HydralazineDisadvantages: delayed onset, variable peak effect, fetal distressDo not give if initial maternal heart rate is >100 beats per minCaution if on calcium channel blocker or beta adrenergic blockerDosing regimen

IV slow push 5-10 mg q 20 min.After response, may give dose hourly

LabetololMechanism - alpha and beta adrenergic blockade (4-8 times more potent on beta than alpha receptors)Kinetics - Onset within 10 minutesSide effects - minor effect on heart rate and cardiac output, tremulousness, headache, hepatotoxicityAdvantages - rapid onset, no change of placental perfusion, useful if maternal tachycardiaDo not use if heart failureDosage regimen

Initial dose 20 mg slow IV then q20 minthen 40 mg then 80 mg q 20 minutes to max 300 mg

Eclampsia

It’s just a seizureMagnesium if not already givenProtect airwayManage hypertensionWhen stable assess fetus if possible

Postpartum hemorrhage

Definitions> 500 cc in 24 hours> 1000 cc in first 24 hours pp10% change in hematocritneed for transfusion

Risk factors: uterine distention, operative delivery, protracted labor, oxytocin, high parity

Postpartum hemorrhage

Causes of deathFailure to identify patients at high risk for hemorrhageFailure to select suitable fluids for transfusion (undertransfusion of blood)Failure to detect and treat disturbances of coagulation

Postpartum hemorrhageAssess volume blood lossGet Help (RN, OB, Anes, techs)IV access/ labs, T&SAGGRESSIVE fluid resuscitationUterine massageFind the source

Tone, Tissue, Trauma, Thrombinfoley catheter, oxygen, blankets, warm fluids

Medical treatmentcontrol of uterine atonycorrection of coagulopathy

Surgical treatmentrepair of lacerationcurretagepackingarterial ligationshysterectomy

Postpartum hemorrhageOxytocin

10-20 units IM, IMMIV Max 40 units/L at 250 ml/hour (if more, hypotension and waterintoxication)Fever, nausea, chills, rigors, hypotension

Methergine0.2 mg IM, IMM Q 2-4 hours*Not with hypertensionCan cause headache, chest pain, palpitations

Hemabate (15 methylF2alpha prostaglandin)250 mcg IM or IMM q 15 min up to 8 doses*Not if asthmaNausea, vomiting, diarrhea, hypertension

Misoprostol (not as effective as parenteral)1000 mcg PR x 1, ?600 mcg buccalFever, nausea, chills, rigors, hypotension

Conclusion

Good communication is a key for successDo not treat pregnant women differently unless there is a specific reason to do soPregnant women uncommonly have significant co morbidities and do have physiology adaptationsFetal evaluation can only be expected of OB care providersSimulation drills are ideal for procedures/events such as: eclampsia, vaginal delivery, hemorrhage, preparation for emergency cesarean section