OB I Flashcards
1
Q
What makes a pregnancy high risk?
A
- 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
2
Q
What is the maternal mortality rate?
most frequent causes?
What are the anesthesia related complications?
A
- 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
3
Q
How is hypertension defined in pregnancy?
What can it cause?
A
- 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
4
Q
What are the complications caused by hypertension during pregnancy?
Neurological
pulmonary
CV
A
- 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
5
Q
What are the complications caused by hypertension during pregnancy?
Hepatic
Renal
Hematological
A
- Hepatic
- impaired function
- elevated enzymes
- hematoma
- rupture
- Renal
- proteinuria
- Na retention
- decreased GFR
- renal failure
- Hematological
- coagulopathy
- thrombocytopenia
- platelet dysfunction
- prolonged PPT?
- DIC
- coagulopathy
6
Q
How does maternal HTN during pregnancy affect the fetus?
A
Impaired uteroplacental perfusion
7
Q
What conditions predispose a woman to pregnancy-induced hytension (PIH)?
A
- Primaparity
- maternal age >40
- african american race
- chronic HTN
- chronic renal disease
- Insulin-dependent diabetes
- history of preeclampsia (maternal- familial)
- Obesity
- multiple gestation
8
Q
What is preeclampsia?
What can it cause?
When does it return to normal?
A
- 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
9
Q
How is preeclampsia categorized (mild vs severe)?
A
- 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:
10
Q
What is Eclampsia?
When does it usually occur?
What are early manifestations?
Treatment?
A
- 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
11
Q
How is preeclampsia treated?
A
- 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
12
Q
How does Magnesium sulfate work?
A
- 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
13
Q
What is the Magnesium sulfate dose?
What are the maternal side effects?
How can you reverse Magnesium sulfate?
A
- 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
14
Q
How does magnesium therapy affect the anesthetic management?
A
- 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
15
Q
What are the key points in managing the anesthetic for a preeclamptic or eclamptic patient?
A
- 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
16
Q
Why is continuous epidural anesthesia preferrable for the preeclamptic or eclamptic patient?
What do you need to be careful of?
A
- 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
17
Q
Why can GA be dangerous in a preeclamptic or eclamptic patient?
A
- exaggerated response to laryngoscopy and intubation
- more airway edema
- avoid ketamine
- exaggerated response to NDMR if on mag sulfate
18
Q
What is HELLP syndrome?
A
- A severe form of preeclampsia characterized by:
- Hemolytic anemia
- Elevated Liver enzymes
- Low Platelet count
- Ranges from mild self-limiting condition to multiorgan failure
19
Q
What is the hallmark sign of HELLP syndrome?
When do they present?
What are the other symptoms?
A
- 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%)
20
Q
What are the problems associated with vaginal delivery after C-section?
A
- Incidence of uterine ruptuer 1%
- Increase in uterine infections
- risk of blood transfusions
- risk of emergency c-sections
21
Q
What is primary dysfunctional labor?
Treatment?
A
- Failure of labor to progress normally d/t:
- ineffective uterine contractions
- arrest of cervix dilation
- Treatment
- oxytocin
- may require anesthesia
22
Q
What are the different breech presentations?
A
A. Complete
B. Incomplete
C. Frank
23
Q
What is this position?
A
Transverse Lie position
24
Q
How is Occiput posterior position different from normal position?
Occiput anterior (normal presentation) pictured here
A
Occiput posterior
25
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
26
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
27
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
28
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
29
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
30
What CCB is used to treat preterm labor?
What are the maternal side effects?
* Nifedipine
* Maternal side effects:
* hypotension
* flushing
* HA
* dizziness
* nausea
31
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
32
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!!
33
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
34
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
* 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)
35
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
36
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
37
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
38
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
* Arterial embolization of uterine/ovarian arteries
* surgical ligation
* hysterectomy
39
