OB I Flashcards
What makes a pregnancy high risk?
- Hypertensive disorders
- antepartum hemorrhage
- diabetes, cardiac, renal, thyroid, neurologic disease, asthma, obesity, drug abuse
- advanced maternal age
- prematurity
- multiple gestation
- fetal malpresentation, placental abruption, compression of umbilical cord, intrauterine infections
What is the maternal mortality rate?
most frequent causes?
What are the anesthesia related complications?
- Maternal mortality in US is 7.5 per 100,000 live births
- pregnancy-induced HTN
- hemorrhage
- PE
- Anesthesia related complications- accounted for 5.2% of maternal deaths
- airway problems/aspiration
- LA toxicity or high block
How is hypertension defined in pregnancy?
What can it cause?
- 7-10% of all pregnancies are complicated by HTN
- mild HTN >140/90 or a rise in SBP of 30 mmHg above baseline or rise in DBP of 15 over baseline
- Severe HTN >160/110
- HTN can cause:
- abruptio placentae
- DIC
- hepatic failure
- cerebral hemorrhage
- others on separate card
What are the complications caused by hypertension during pregnancy?
Neurological
pulmonary
CV
- Neurological
- HA
- visual disturbances
- hyperexcitability
- sz
- intracranial hemorrhage
- cerebral edema
- Pulmonary
- upper airway edema
- pulmonary edema
- CV
- decreased intravascular volume
- increased arteriolar resistance
- heart failure
What are the complications caused by hypertension during pregnancy?
Hepatic
Renal
Hematological
- Hepatic
- impaired function
- elevated enzymes
- hematoma
- rupture
- Renal
- proteinuria
- Na retention
- decreased GFR
- renal failure
- Hematological
- coagulopathy
- thrombocytopenia
- platelet dysfunction
- prolonged PPT?
- DIC
- coagulopathy
How does maternal HTN during pregnancy affect the fetus?
Impaired uteroplacental perfusion
What conditions predispose a woman to pregnancy-induced hytension (PIH)?
- Primaparity
- maternal age >40
- african american race
- chronic HTN
- chronic renal disease
- Insulin-dependent diabetes
- history of preeclampsia (maternal- familial)
- Obesity
- multiple gestation
What is preeclampsia?
What can it cause?
When does it return to normal?
- Condition characterized by:
- vasoconstriction
- hypovolemia
- coagulation abnormalities
- poor organ perfusion
- Defines as new onset HTN that occurs after the 20th week gestation with proteinuria
- Can cause:
- cerebral bleeds
- pulmonary edema
- hepatic rupture
- HELLP syndrome
- Returns to normal within 3 months after delivery
How is preeclampsia categorized (mild vs severe)?
- Mild
- HTN:
- 140/90 or greater or
- increase of 30 mmHg above systolic or
- 15 above diastolic
- Proteinuria: >500 mg/day
- HTN:
- Severe
- HTN:
- 160/110 or greater
- Proteinuria:
- >5 g/day and/or
- oliguria (UOP < 500 ml/day)
- evidence of severe end-organ damage
- oliguria
- cerebral disturbances
- pulmonary edema
- epigastric pain or impaired liver fxn
- intrauterine growth retardation
- HTN:
What is Eclampsia?
When does it usually occur?
What are early manifestations?
Treatment?
- Preeclampsia (HTN, edema, and proteinuria) with seizures
- Life-threatening emergency
- most common in 3rd trimester
- Early CNS manifestations are HA and visual disturbances
- Treatment:
- Oxygen (ABC’s)
- LUD
- IV access
- Mag sulfate
- antihypertensives
- fluid balance
- coag studies
- fetal monitoring and resuscitation
How is preeclampsia treated?
- Mainstay of therapy is to control HTN, prevent seizures, and deliver fetus
- Treatment of maternal HTN (a-line)
- goal is DBP <110
- labetalol and hydralazine commonly used
- other options Nitroglycerine or nifedipine
- want to gradually decrease BP- may cause fetal distress to drop too quick
- Seizure prophylaxis with Magnesium sulfate
- Correct hypovolemia (hydration, foley)
- Correct coagulation abnormalities
- Correct acid/base and electrolyte abnormalities
- assure fetal viability
How does Magnesium sulfate work?
- drug of choice for hyperreflexia, prevention and control of sz related to preeclampsia and eclampsia
- Causes relaxation of vascular, bronchial and uterine smooth muscle
- decreases cerebral irritability and prevents/treats sz
- mildly sedates
- vasodilates (caution hypotension)
- decreases uterine tone
- potentiates the action of depolarizing and non depolarizing muscle relaxants
- croses placenta and causes neonatal hypotonia and respiratory depression
What is the Magnesium sulfate dose?
What are the maternal side effects?
How can you reverse Magnesium sulfate?
- Dose:
- bolus 4 g IV over 10 minutes
- maintenance: 1 6/hr IV infusion
- Maternal side effects:
- flushing
- HA
- dizziness
- skeletal muscle weakness
- deep tendon reflex depression
- respiratory depression
- pulmonary edema
- **monitor serum levels for toxicity
- Revers the effects of Mag sulfate by administering Calcium
- Calcium gluconate 1 gm or calcium chloride 300 mg
How does magnesium therapy affect the anesthetic management?
- It potentiates depolarizing and non-depolarizing neuromuscular blockers
- Never administer defisiculating dose of NMB
- Standardize dose of Sch to 1 mg/kg
- Administer 1/2 to 1/3 maintenance dose of non-depolarizers
- Dose by PNS
- Mag sulfate antagonizes vasoconstrictive effects of alpha agonists, so ephedrine and phenylephrine are less effective
What are the key points in managing the anesthetic for a preeclamptic or eclamptic patient?
- Assess sz control and neurologic status
- assess airway
- correct hypovolemia with colloid fluid bolus (250-500 ml)
- control BP (DBP <100)
- Consider A-line, CVP, SWAN
- continuous FHR monitoring
- oxygen to parturient
- Lab workup:
- CBC
- renal profile
- liver function tests
- Pt/PTT
- FDP- fibrin degredation products
- FSP- fibrin split products
- TEG
- platelet count
Why is continuous epidural anesthesia preferrable for the preeclamptic or eclamptic patient?
What do you need to be careful of?
- May improve maternal HTN and improve organ blood flow, uteroplacental perfusion and fetal oxygenation
- Gradual onset of sympathetic block
- CV stability
- avoids neonatal depression
- Avoids airway instrumentation
- Careful with:
- hypotension (esp SAB) and its affect on uteroplacental flow
- Avoid regional if signs of increased ICP, coagulopathies or severe hypovolemia
Why can GA be dangerous in a preeclamptic or eclamptic patient?
- exaggerated response to laryngoscopy and intubation
- more airway edema
- avoid ketamine
- exaggerated response to NDMR if on mag sulfate
What is HELLP syndrome?
- A severe form of preeclampsia characterized by:
- Hemolytic anemia
- Elevated Liver enzymes
- Low Platelet count
- Ranges from mild self-limiting condition to multiorgan failure
What is the hallmark sign of HELLP syndrome?
When do they present?
What are the other symptoms?
- Hallmark sign of HELLP is hemolysis (microangiopathic hemolytic anemia)
- Most present preterm (20% postpartum)
- Other signs and symptoms:
- Malaise (90%)
- epigastric pain (90%) ** most common initial symptom
- N/V (50%)
- Evidence of preeclampsia before delivery (80%)
What are the problems associated with vaginal delivery after C-section?
- Incidence of uterine ruptuer 1%
- Increase in uterine infections
- risk of blood transfusions
- risk of emergency c-sections
What is primary dysfunctional labor?
Treatment?
- Failure of labor to progress normally d/t:
- ineffective uterine contractions
- arrest of cervix dilation
- Treatment
- oxytocin
- may require anesthesia
What are the different breech presentations?
A. Complete
B. Incomplete
C. Frank
What is this position?
Transverse Lie position
How is Occiput posterior position different from normal position?
Occiput anterior (normal presentation) pictured here
Occiput posterior
What problems are multiple gestation pregnancies associated with?
- Premature labor
- abnormal fetal presentations
- PIH
- Increased risk of postpartum hemorrhage (uterine atony)
- may require higher doses of oxytocin for uterus to contract
- Do not start until all fetuses delivered
- Increase anesthesia morbidity
- prone to aortocaval compression
- prone to hypoxia (greatly reduced FRC)
- Risk high spinal/epidural blockade
Anesthesia for multiple gestations
Labor and delivery
twins
triplets (+)
- Labor and delivery
- continuous epidural analgesia/CSE
- Constantly be prepared for emergency C/S
- Twins
- double “set up”
- Sometimes GA is required to facilitate delivery of 2nd twin
- Triplets +
- C/S preferred route of delivery
- epidural or spinal
What is preterm labor?
What determines survivability of the infant?
- Preterm labor- regular uterine contractions that occur between 20-37 weeks of gestation that result in dilation or effacement of cervix
- Survivability of infant depends on the maturity of major organs as well as gestational age/fetal size
- Pre-term labor is leading cause of perinatal morbidity and mortality
What are the maternal risk factors for premature labor?
(15)
- History of preterm delivery
- young age (<18) or old age (>35)
- low socioeconomic status
- acute or chronic illness
- trauma
- abdominal surgery during pregnancy
- infection (genital, UTI)
- pyelonephritis
- smoking
- drug use
- obesity
- multiple gestation
- abnormal fetal presentation
- low prepregnancy BMI
- abnormal uterine/cervical anatomy
How is premature labor treated?
- Bedrest
- FHR monitoring
- check for PROM
- abx to prevent maternal chorioamnionitis
- Progesterone therapy
- Tocolytic agents (to suppress uterine activity)
- CCB- Nifedipine
- Prostaglandin inhibitors (NSAIDS- Indomethacin, ketorolac)
- Beta-2 agonists
- Mag sulfate
- Corticosteroids for fetal lung development
What CCB is used to treat preterm labor?
What are the maternal side effects?
- Nifedipine
- Maternal side effects:
- hypotension
- flushing
- HA
- dizziness
- nausea
What are the cyclooxygenase inhibitors used to treat preterm labor?
Maternal side effets?
Fetal side effects?
- NSAIDS- Indomethacin, ketorolac, sulindac
- Maternal side effects:
- nausea
- heartburn
- Fetal side effects:
- constriction of DA
- Pulmonary HTN
- reversible renal dysfunction
- intraventricular hemorrhage
What beta agonist is used to treat preterm labor?
How does it work?
Maternal side effects?
Fetal side effects?
Neonatal side effects?
- Terbutaline
- tocolysis- smooth muscle relaxation, including uterus; also increases HR, SV, CO
- Maternal SE
- cerebral vasospasm
- CP ??
- tachycardia
- arrhythmias
- MI
- hypotension
- hyperglycemia
- hypokalemia
- ileius
- Nausea
- palpitations
- pulmonary edema
- Fetal SE
- fetal tachycardia
- hyperinsulinemia
- Neonatal SE
- hypoglycemia
- hypocalcemia
- tachycardia
- hypotension
- ***Careful with fluids, pulmonary edema!!
Magnesium Sulfate for Tocolysis:
What does it do?
Dosage
Neonatal effects?
- Causes relaxation of vascular, bronchial, and uterine smooth muscle
- Dose: (same as previous dose learned)
- Bolus 4 g IV over 10 min
- Maintenance 1 g/hr IV
- Therapeutic serum mag level of 4-9 mg/dL for tocolysis
- Maternal SE same as previous card
- Neonatal SE:
- lethargy
- hypotension
- hypotonia
- resp distress
What is the goal for vaginal delivery of a preterm infant?
How is the anesthesia done?
Why is GA not ideal?
- Goal during vaginal delivery is slow and controlled with minimal pushing by the mother
- make larger episiotomy
- low forceps
- Spinal and/or Epidural analgesia
- complete pelvic relaxation
- may add IV NTG
- better apgar scores compared to GA
- can have depressant effects on fetus
- watch fluid preloading with beta agonists d/t risk of pulm edema
- complete pelvic relaxation
- GA- fetus is more vulnerable
- decreased protein available for drug binding
- elevated bilirubin levels that compete for drug binding sites
- immature blood brain barrier in the fetus
- decreased ability to metabolize and excrete drugs
- higher affinity towards acidosis (ion trapping)
What is significant regarding hemorrhage in an OB patient?
What is average blood loss for vaginal delivery?
Cesarean section?
- Hemorrhage in the OB patient is often unexpected and can lead to death within minutes
- Antepartum hemorhage occurs in association with placenta previa and abruptio placentae
- Average blood loss for vaginal delivery is 500 ml
- Average blood loss for c-section is 800-1000 ml
- with hysterectomy expect 1500 ml
- Blood loss is usually well tolerated and rarely requires transfusion
What inherent compensation mecanisms does the parturient have?
- 35-50% increase in blood volume
- 500 ml autotransfusion from uterine involution during placental expulsion
- increased renin, ADH and catecholamines
- help maintain plasma volume, CO and perfusion pressure
- hypercoagulable with extra coagulation factors
What are some key points regarding blood loss in the parturient?
- Blood loss is usually underestimated
- Need good IV access- at least 2 large bore
- IV volume replacement is more important than Hct/Hgb
- Rapid fluid infusion is more important than type of fluid
- Type-specific uncrossmatched blood is preferable to O-neg for emergency transfusion
- If parturient is bleeding severely, do not delay surgery for labs tests
- Give mother oxygen
- Do not hesitate to call for help
What can be used to treat bleeding?
- Drugs:
- Oxytocin: 20-40 units in 1 L IV fluid
- 10 units IM
- small incremental IV injections of 2-3 units
- Ergot alkaloids
- methylergonovine (methergin)
- Ergonovine (Ergotrate)
- 0.2 mg IM
- Prostaglandins
- 15- methyl prostaglandine F2-alpha
- 0.25 mg IM/intrauterine
- 15- methyl prostaglandine F2-alpha
- Oxytocin: 20-40 units in 1 L IV fluid
- Arterial embolization of uterine/ovarian arteries
- surgical ligation
- hysterectomy
