Obstetrics: Anesthesia for Complicated Pregnancy Flashcards
What is labor that occurs between 20 & 37 weeks?
Premature labor
What percentage of deliveries are premature?
8%
What are contributing factors to premature labor?
- Extremes of age
- Inadequate prenatal care
- Infections
- Prior preterm labor
- Multiple gestations
T OR F:
Preterm infants under 30 weeks and weighing less than 1500 G have more complications than term infants
TRUE
What is the most common complication in premature babies?
Inadequate surfactant levels and low lung maturity
At what age does surfactant become adequate?
35 weeks
What is PROM?
Premature rupture of membranes
What happens during PROM?
Leakage of amniotic fluid that occurs before the onset of labor
What is incidence of PROM?
- 10% of all pregnancies
- - 35% of all premature deliveries
What are contributing factors to PROM?
- History of PROM or premature labor
- Multiple gestations
- Smoking
- Infections
T or F:
Spontaneous labor starts within 24 hours of PROM in 90% of patients
TRUE
If PROM occurs before 34 weeks gestation, what is course of action?
Stop the pregnancy if you can
Start antibiotics
Start tocolytics for 5-7 days
If PROM occurs after 34 weeks gestation, what is course of action?
Deliver the baby
Chorioamnionitis is what?
Infection of the chorionic and amnionic membranes that may or may not involve the placenta, uterus, and umbilical cord
What is chorioamnionitis usually associated with?
PROM
What are some maternal complications of chorioamnionitis?
- Dysfunctional labor
- Septicemia (infection)
- Postpartum hemorrhage
What are some fetal complications of chorioamnionitis?
- Premature labor
- Acidosis
- Septicemia (infection)
What are clinical signs of chorioamnionitis?
- Fever >38* C
- Maternal and fetal tachycardia
- Foul smelling or purulent amniotic fluid
Is regional anesthesia safe for patients that have chorioamnionitis?
Is safe as long as no signs of septicemia at placement site
What has happened when an onset of sudden fetal bradycardia and profound decelerations is noted?
Umbilical cord prolapse
when umbilical cord is wedged between baby and canal possibly kinking off cord
What are predisposing factors of umbilical cord prolapse?
- Excessive cord length
- Malpresentation ( baby not head down)
- Grand parity >5 ( history of more than 5 pregnancies)
- Multiple gestations
What is treatment for umbilical cord prolapse?
- Immediate steep trendelendburg
- - Pushing of fetus back into pelvis until stat C-section can be performed
What is an entry of amniotic fluid into the maternal circulation that occurs through any break in uteroplacental membranes?
Amniotic fluid embolism
What is the mortality rate of an amniotic fluid embolism?
86%
What does amniotic fluid contain?
- Fetal debris
- Prostaglandin
- Leukotrienes
What is incidence of Amniotic fluid embolism?
Very rare, but accounts for 10% of all maternal deaths with 50% mortality rate in 1st hour
What is the classic triad of symptoms to present during an amniotic fluid embolism?
- Acute hypoxemia
- Hemodynamic collapse w/ severe hypotension
- Coagulopathy without obvious cause
What are the 3 main pathophysiological manifestations with amniotic fluid embolism?
1) Acute pulmonary embolism
2) DIC
3) Uterine atony
What is the treatment for an amniotic fluid embolism?
- Resuscitation and supportive care
- CPR
- Immediate delivery of baby improves maternal and fetal outcome
What are 3 types of partum hemorrhages?
- Antepartum
- Peripartum (intrapartum)
- Postpartum
What is antepartum?
Placenta previa
Placental abruption
What is peripartum?
Uterine rupture
What is postpartum?
Placenta accreta (placenta grows through endometrium) Uterine atony
What is placenta previa?
Complication in which placenta is wedged into uterine segment
What are 3 types of placenta previa?
- Central or complete previa (37% of time)
- Incomplete or partial previa ( 27% of time)
- Low lying or marginal previa (46 % of time)
What is complete placenta previa?
Placenta completely covers internal cervical OS
What is partial placenta previa?
Placenta partially covers internal cervical OS
What is marginal placenta previa?
– Placenta is close to the internal cervica OS without extending beyond its edge
(The anterior lying placenta previa increases risk of excessive bleeding during C/S)
What is incidence of placenta previa?
0.5%
Goes up to 5% for subsequent pregnancies
What risk factors are associated with placenta previa?
- Scarring of uterine wall
- Many previous pregnancies
- Abnormally developed uterus
What is most common symptom of placenta previa?
Painless vaginal bleeding
What is the management of placenta previa for a women less than 37 weeks gestation?
Bedrest and observation
What is the management of placenta previa for a women after 37 weeks gestation?
C/S
When can you deliver vaginally with placenta previa?
When marginal placenta previa exist and bleeding is only mild
T or F:
All patients with vaginal bleeding are assumed to have placenta previa until proven otherwise
TRUE
What type of anesthetics can you use for placenta previa?
– Regional if patient is hemodynamically stable and no active bleeding
– General with stat C/S if active bleeding or patient is unstable
For most OB procedures, how much blood needs to be crossmatched and available for transfusion?
2 units
What is a premature separation of normal placenta after 20 weeks of gestation?
Placenta abruption
How does placenta abruption cause fetal distress?
The separation of placenta equates for a loss of area for maternal-fetal gas exchange causing fetal distress
What is the most common cause of intrapartum fetal death?
Placental abruption
What are some risk factors for placental abruption?
- HTN
- Trauma
- Prolonged PROM
- Tobacco, alcohol, cocaine usage
- Short umbilical cord
What are some symptoms of placental abruption?
- Painful vaginal bleeding
- HTN
- Uterine tenderness
What is the unique diagnosis for placental abruption?
Amniotic fluid is port wine colored
Minimal placental abruption is characterized by what?
- Preterm with no fetal distress
- - Patient is hospitalized and pregnancy allowed to continue until fetal lung maturation
Mild to moderate placental abruption is characterized by what?
– If >37 weeks and no fetal distress, then vaginal delivery is allowed
– If fetal distress is apparent, then immediate C/S
– Fibrinogen levels are mildly reduced and patient starting to get to DIC
Severe placental abruption is characterized by what?
– Fibrinogen, Factor 5 and 7, and platelet counts all low
– Is life threatening emergency and requires STAT C-section
What is IFD?
Intrauterine fetal demise
What type of anesthetic is preferred for placental abruptions?
General b/c of high blood loss and required treatment of hyprovolemia
What is a uterine rupture?
When the integrity of the myometrial wall is breached that typically occurs during active labor
What are the signs and symptoms of uterine rupture?
- Frank hemorrhage that causes hypotension
- Fetal distress (most reliable sign)
- Abdominal pain that breaks through epidural
- Constant pain that has no relief between contractions
What is the treatment for a uterine rupture?
Volume resuscitation & immediate laparotomy
What is a retained placenta?
Placenta fragments that are still attached to uterus after delivery
What is the detrimental effect of a retained placenta?
When fragments are still attached, causes the uterus to not be able to contract properly and cause open blood vessels and sinuses to continue to bleed profusely
What is treatment for retained placenta?
Manual exploration of uterus
— Nitroglycerin may be useful in relaxing the uterus
What is an abnormally adherent placenta?
Placenta accreta
What are 3 types of plenta accreta?
- Placenta accreta vera
- Placenta increta
- Placenta percreta
Which placenta accreta is an invasion of the myometrium and occurs around 17% of time?
Placenta increta
Which placenta accreta is only an adherence to the myometrium without invasion or passage through uterine muscle?
Placenta accreta vera
occurs majority of time ~78%
Which placenta accreta is an invasion of the uterine serosa or other pelvic structures (like a through and through of myometrium) and only occurs around 5% of time?
Placenta percreta
When is diagnosis made for placenta accreta?
Usually during separation of placenta at delivery and is confirmed by laparotomy
What is the treatment for placenta accreta?
– Uterine curretage and oversewing can be tried but rarely works
– Most require C/S and a postpartum hysterectomy/laparotomy to repair
What is uterine atony?
Condition in which uterus is not contracting down
What is uterine atony usually accompanied with?
Retained placenta
What is treatment for uterine atony?
Oxytocin
if really severe then mertherigine and then if more contraction needed then hemabate
What is the 1st line drug treatment that all patients receive to help with uterine contraction?
Oxytocin
What is the major side effect of oxytocin and what must be done to ensure this doesn’t occur?
Hypotension
Give drug slowly as hypotension usually only comes on when drug given too quickly
T or F:
Oxytocin stimulates both the frequency and force of contractile activity
TRUE
What is normal postpartum dose given of oxytocin?
20 units diluted in 1000 mL
Titrate infusion to around 30 mU/min
What is onset and half life of oxytocin?
Onset : 1 min
Half life: 1-5 min
What is 2nd line drug therapy used to aid uterine contraction?
Methylergonovine maleate or METHERGINE
How does methergine work?
Works directly on smooth muscle of uterus via alpha receptors
What side effect do you usually see with methergine?
Increased CVP and BP
What is the dose of methergine?
IM : 0.2 mg
IV : 0.02 mg
Onsets: IM = 2-5 min
IV= immediate
What patient population must you use caution with if giving methergine?
- Preeclampsia (because already HTN)
- HTN
- Asthmatics
- Cardiac disease (because increase in CVP)
What is the last line drug therapy used for uterine contractions?
Prostaglandin f2alpha or HEMABATE or carboprost
What is dose of hemabate and what is maximum dose?
IM : 250 mcg
Repeated every 15 min intervals
Max dose : 2 mg
T OR F:
You can give hemabate to asthmatics freely
FALSE
be very cautious with asthmatics
For a uterine inversion, what can your blood loss be and what is effect of this?
EBL can be 700 mL/min
Cause patient to become hypotensive
What can you give to help OB treat uterine inversion?
NTG and Sevo to relax uterus
Which condition presents with NO pain, NO fetal distress, and lots of bleeding
Placenta previa
Which condition presents with pain, fetal distress, and lots of bleeding (some of which can be concealed/hidden from us)
Placenta abruption
Which condition presents with pain, LOSS of fetal heart rate, and lots of bleeding
Uterine rupture
Which condition presents postpartum with NO pain with some bleeding
Retained placenta
Which condition presents postpartum with NO pain with lots of bleeding
Placenta accreta
Which condition presents postpartum with NO pain with some bleeding
Uterine atony
Uterine atony and retained placenta both present the same
But remember uterine atony is usually accompanied by a retained placenta so to diagnose rule out atony, not retained placenta
What are most common causes of HTN in pregnancy?
- Pt chronic HTN
- PIH (pregnancy induced HTN)
- Preeclampsia / Eclampsia
- HELLP syndrome
What is defined as a chronic HTN?
Systolic BP > 140 mmHg or Diastolic > 90 mmHg before 20 weeks gestation
What is the safe beta blocker that can be given to chronic HTN patients that are pregnant?
Labetolol
How is PIH defined?
Same as chronic ( S >140 and D > 90) but brought on by pregnancy
– Can also be defined as consistent increase in S or D pressures by 30 mmHg & 15 mmHg above patients normal baseline BP
What is triad of symptoms of preeclampsia?
1) HTN
2) Proteinuria
3) Edema after 20 weeks that resolves 48 hours after delivery
What are some of the risk factors for preeclampsia?
- Primigravidas (1st baby)
- Obesity
- Chronic HTN
- Previous history
What is the pathophysiology of preeclampsia?
COMPLICATED AND NOT UNDERSTOOD so no one knows
Severe preeclampsia is defined as what?
S > 160 mmHg or D > 110 mmHg OR Proteinuria > 5 G / 24 hours OR *Cerebral edema causing headache * Pulmonary edema * Oliguria (< 400 mL / 24 hours) * Platelets < 100000
T or F:
Severe preeclampsia contributes to 20-40% of maternal deaths and 20% of perinatal deaths
TRUE
What is HELLP syndrome?
PIH associated with:
hemolysis
elevated liver enzymes
low platelet counts
Which type of anesthetic is needed for HELLP syndrome?
GA
regional is contraindicated because actively falling platelet count
When does preeclampsia turn into eclampsia?
When seizures occurs
What is treatment for preeclampsia?
- -Bedrest
- Antihypertensives
- Magnesium sulfate
What antihypertensives are safe for pregnancy?
- Labetolol 5-10 mg
- Hydralazine 5 mg
- Methyldopa 250-500 mg PO
- Mag sulfate
- Nitroprusside
What is mag sulfate used for ?
Treat hyperreflexia and prevention of seizures because it reduces CNS irritability
What is the goal therapeutic level of mag sulfate?
4-6 mEq / L
What are normal levels of mag sulfate?
1.5-2 mEq / L
What are detrimental effects of increased levels of mag sulfate?
Start to have detrimental effects on heart
What are ranges for excess mag sulfate and what does each cause?
: 5-10 eEq / L causes ECG changes
: 10 mEq causes respiratory depression and weakness
: 15 mEq causes SA and AV blocks
: 25 mEq causes cardiac arrest
Which drug poses a risk of cyanide toxicity to the fetus in large doses?
Nitroprusside
What is only definitive treatment to preeclampsia?
Delivery of fetus and placenta
Does mild preeclampsia require a C/S?
NO
patients just pose higher risk so just be careful and cautious
For severe preeclampsia patients, what is anesthetic plan.
- A line always
- On antihypertensives
- Monitor urine output closely
- Hypovolemia corrected slowly ( no more than 500 mL crystalloid)
- Check platelet counts frequently (no regional if counts < 80000)
- EPIDURAL OR SPINAL 1st CHOICE
Why are epidurals preferred in preeclamptic patients?
- Avoids risk of failed intubation
- Avoids hypotension
- Improves uteroplacental perfusion by 75% in PIH patients
When treating patients with hypotension, what must you do to doses of drugs given?
REDUCE them
ephedrine 5mg at at time
phenylephrine 50 mcg at a time
What does mag sulfate do to non-depolarizing muscle relaxants?
Potentiates them so require much less of drug
What is true of regurgitant valves during pregnancy?
- Pregnancy tolerated well
- Regional anesthesia well tolerated
- Avoid pain, increased CO2, decreased O2, avoid myocardial depression
What is 2nd most common valve defect in pregnant patients?
Mitral regurg
How should you handle patients with regurg?
- Avoid bradycardia
- Avoid HTN
- Consider afterload reduction
Which valve defect may develop after an attack of rheumatic fever?
Aortic regurg
What is true of stenotic valves during pregnancy?
- Pregnancy poorly tolerated
- Consider invasive monitoring
- Maintain normal HR
With mitral stenosis, what do you have to watch out for?
- Avoid sinus tachycardia
- Avoid A fib
- Avoid increases in blood volume
How should you handle patients with aortic stenosis?
- Avoid decreased SVR
- Avoid bradycardia
- Avoid hypovolemia
Just for review, what are left to right shunts?
- VSD
- ASD
- PDA
Just for review, what is the right to left shunt?
- ToF (tetrology of fallot)
1) RV hypertrophy / RV outflow obstruction
2) Overriding aorta
3) VSD
How can cardiomyopathies present in pregnancy?
Fatigue or URI/ congestion
What are the risk factors for cardiomyopathy in pregnancy?
- Multiple gestations
- Preeclampsia
- Obesity
- Advanced maternal age
What is incidence and risk factors of gestational diabetes?
4% of pregnancies
- Advanced maternal age (AMA)
- Obesity
- DM or family history of DM
- H/O of stillbirth or neonate death
What are effects on mother of gestational diabetes?
- PIH increased likelihood
- C-section likelihood
- Preterm labor likelihood
- Polyhydramnios (increased amount of amniotic fluid)
What are effects on fetus of gestational diabetes?
- Larger birth weight
- Structural malformations
- Neonatal hypoglycemia
- Neonatal respiratory distress syndrome
What is macrosomia?
Large birth weight or baby large for gestational age
Increases likelihood of injury/trauma to mother and fetus during delivery
T or F:
Hyperglycemia during period of critical organogenesis before 7th week postconception in single strongest factor in DM pregnant women
TRUE
From question above, known this
Basically blood sugar during 1st trimester must be tightly controlled to lower risk of any harm done by DM to mother and fetus
T or F:
CNS structural malformations are the most common malformation caused by DM to fetus?
FALSE
is 2nd most common
CARDIAC is most common
What is target glucose concentration for pregnancy?
=< 100 mg/dL
T or F:
Asthma has a variable course of action in pregnancy (may improve may worsen may remain the same)
TRUE
What is normal pregnancy ABG?
Respiratory alkalosis
pH 7.44
pCO2 30
pO2 105
What is normal non pregnant ABG?
pH 7.35
pCO2 30-40
pO2 85
What are the goals for asthmatics during labor?
- Regional anesthetic is preferred
- Avoid pain
- Avoid hypo and hyper carbia
- Provide minimal sedation
For a stable asthmatic, what is management goal?
- Regional preferred
- - Avoid endotracheal intubation
For an unstable asthmatic, what is management goal?
- Regional REALLY PREFERRED
- If GA, pretreat with albuterol
- RSI
- High MAC (1.5)
- Albuterol before extubation
For C/S in obese patients, what 2 detrimental risks are increased?
- Incidence of fetal distress
- - Abnormal labor (arrest of descent)
For morbidly obese patients, what detrimental outcomes are increased?
- Incidence of shoulder distocia
- - RIsk of maternal death