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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
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