placenta previa

placental abruption

uterine rupture

What % of pregnancies does postpartum hemorrhage occur in?

most common causes? (5)

What anesthetic can cause decreased uterine tone?

~10%

uterine atony

vaginal tears

retained placenta

placenta accreta

uterine inversion

Volatile anesthetics

What is placental abruption?

 Risk factors: (6)? Acronym?

- is partial or complete separation of the placenta before delivery of the fetus.

Cocaine Use

HTN/Preeclampsia

Advanced Age

Premature membrane rupture

Trauma

Alcohol use

Previous hx of abruption

Smoking

CHAP TAPS 

vaginal bleeding+/-

uterine tenderness

increased uterine activity

fetal distress

DIC

Delivery 

Restoration of blood volume

Management of accompanying DIC

hemorrhagic shock

(bleeding may be conceled)

renal failure

fetal distress or demise
(~20% of all perinatal deaths)

coagulopathy

(~10% incidence with abruption)

fetus is dead

no evidence of fetal distress (abruption is mild)

placenta implanted in advance of the presenting fetal part

"the placenta is between the baby and the escape hatch" --Ron Anderson

total - placenta completely covers the cervical os

partial - placenta partially covers the cervical os

marginal - placenta lies close to, but does not cover the cervical os

What is the incidence of placenta previa?

Associated conditions? (4)

~1/200 pregnancies

associated conditions:

Multiparity

Advanced maternal age

Previous placenta previa

Previous C/S or other uterine surgery

MAPP

painless vaginal bleeding, often preterm (2nd or 3rd trimester) and typically stops spontaneously following first episode---no contractions with bleeding.

pass on pushing = need C/S

When is the 1st episode of bleeding with placenta previa?

What usually stimulates the onset of bleeding?

usually preterm and painless

nothing; it is spontaneous

acute

uteroplacental insufficiency from placental separation

preterm delivery

chronic

 IUGR from decreased placental blood supply

What are the anesthetic considerations of placenta previa?

What is the main tx of placenta previa?

assessment of fluid volume

risk of increased intraop blood loss

type of anesthetic dependent on patient condition

-- GETA probably necessary for significant hemorrhage or hypotension but if pt stable and w/o coagulaphathies then can do epidural or spinal

Bedrest and observation to try to allow the fetus to grow

1. active labor starts
2. lungs are mature
3. fetus is 37 weeks
4. excessive bleeding occurs

~1% in patients with a previously scarred uterus 

ie. VBAC

Rare complication in an unscarred uterus

grand multiparity

overaggressive use of oxytocin

previous uterine surgery

uterine manipulation

ie. external version = trying to turn the baby by manipulating pts belly

trauma

GO PUT

What are the s/sx of uterine rupture? (5)

Which sign is most reliable? Inconsistent?

vaginal bleeding

hypotension

cessation of labor

fetal distress = most reliable sign

abdominal pain is an inconsistent sign per Ron but Valley says continuous abdominal pain is seen

 Definitive treatment for uterine rupture is ____. 

Definitive procedure is hysterectomy

Some patients can have uterine repair

if pt has a uterine repair they will not be able to labor again; no VBAC

GA typically preferred with uterine rupture except with a stable patient having a pre-existing epidural

What is vasa previa?

What is this configuration susceptible to?

velamentous insertion of the cord where the blood vessels traverse the membranes ahead of the presenting part

basically cord vessels are across os so the baby may rupture them when being birthed

susceptible to tearing of vessel with rupture of membranes 

% fetal mortality in vasa previa?

blood volume of preterm fetus?

fetal mortality rate = 50-75%

blood volume = about 250ml (80ml/kg)

What is postpartum hemorrhage defined as?

 Incidence?

>500ml of blood after delivery

 up to ~10% incidence

primary - within 24 hours of delivery - carries↑ M&M

secondary - between 24 hours and 6 wks postpartum

uterine atony

An atonic, engorged uterus may hold __mL of blood?

*Management of pp hemorrhage is with 2 main drugs, list 2 others less used?

1000ml

#1 - oxytocin

(stimulates uterine tone)

#2 - Hemabate

 (15-methylprostaglandin F2alpha -- PGF2 = stimulations of uterine tone)

misoprostol 

(PGE1 a cervical ripening agent)

orgonovine & methylergonovine (Methergine)

Methylergometrine is a blood vessel constrictor and smooth muscle agonist most commonly used to prevent or control excessive bleeding following childbirth and spontaneous or elective abortion.

lacerations & hematomas (perineal, vaginal, or cervical)

retained placenta

placenta accreta

uterine inversion

1. placenta accreta vera - adheres
2. placenta increta - invades
3. placenta percreta - penetrates

adherence of placenta directly to the myometrium  without invasion of the uterine mm

(a normal uterus just adheres to the actual muscle wall)

What is placenta percreta?

Is this type easy to remove?

invasion of the uterine serosa or other pelvic structures by the placenta -- like a tumor

most difficult to remove & usually requires total hysterectomy with possibility of severe hemorrhage

 epidemiology of placenta accreta

Increased incidence of this with _______?

Another big red flag for this issue is _____ in a pt with prior ______.

Increased incidence of placenta acreta is directly proportional to _____________________________?

increased incidence with prior uterine trauma

placenta previa in a patient with prior C/S should raise suspicion (placenta likes to implant in area of scaring - per Ron) 

directly related to number of previous C-Sections

INCREASED VENOUS STASIS in pelvis & LE's due to vena caval compression by uterus

HYPERCOAGULABLE STATE - particularly in the immediate pp period as fibrinolytic activity↓ with coagulation activity remaining elevated

VASCULAR INJURY ASSOCIATED WITH DELIVERY - leads to an increase in coagulation activity

1. dyspnea
2. palpitations
3. anxiety
4. pleuritic chest pain
5. cough
6. tachycardia
7. JVD

~10%

 TX: adequate oxygenation

support of maternal circulation & uterine BF

immediate anticoagulation or venous interruption (ie greenfield filter)

A venous air embolism is a common occurrence during C/S.

What increases this incidence?

Are these common? 

increased incidence with:

steep trendelenburg

exteriorization of the uterus

small ones are very common and usually no big deal

What are the s/sx of a massive air embolism?

What s/sx are seen more commonly with smaller air embolism?

massive air embolism - sudden hypoxia, hypotension, cardiac arrest

more commonly - chest pain, decreased O2 saturation, dyspnea, & maybe EKG changes

What is the incidence of an amniotic fluid embolus?

Is the mortality rate high? How fast can the pt die?

RARE ---- Incidence ~1:200,000

YES - 50-85% in first hour

What is the mortality of an amniotic fluid embolus?

2/3 of deaths within first ___ hours.

High incidence of permanent ____ injury in survivors.

What does NOT correlate with severity?

mortality 50-80%

 2/3 of deaths within first 5 hours

High incidence of permanent neurologic injury in survivors

Volume of particulate matter found in lungs does not correlate with severity

What is the pathophys of an amniotic fluid embolus?

amniotic fluid gets into the maternal circulation d/t breaks in the uteroplacental membranes

How long does the early phase of an amntiotic fluid embolus last? What happens in this time?

Second phase? If pt survives second phase what needs to be monitored besides the permanent neurologic isses?

early phase - less than 30 minutes duration

intense pulmonary vasospasm with release of vasoactive substances leading to often fatal right heart failure

second phase

left ventricular dysfunction in survivors of the early phase - etiology unclear

almost all develop coagulopathy

An amniotic fluid embolus may be more accurately described as an ______ reaction versus an embolic one.

Treatment?

anaphylactoid rxn

CPR  and supportive care --- if mom survives tx DIC

maternal mortality in the US

Overall?

Anesthesia related?

overall = 9.2/100,000 

anesthesia related= 1.7/1,000,000

List causes and % of the deaths occurring with GA:(6)

Basically what has been responsible for most anesthesia related maternal deaths?

of the deaths occurring with GA:

33% aspiration

22% induction/intubation

22% cardiac arrest

15% inadequate ventilation

5%   unknown

3%   respiratory faiure

*Airway issues*

What is the preferred technique for dealing with meconium aspiration in the infant?

What determines whether or not you will ET suction the infant after birth?

early pharyngeal suctioning of baby

ie. delivery of the head, suctioning of the hypopharynx, then delivery of the thorax

(OB does this)

if infant is vigorous, no ET suctioning indicated

if not vigorous, tracheal suctioning should be performed prior to PP ventilation

If a previously vigorous infant develops respiratory compromise, tracheal suctioning should be done prior to?

if a previously vigorous infant develops respiratory compromise, tracheal suctioning should be done prior to PPV.

*What is the most common cause of DIC in pregnancy?

placental abruption = DIC

(incidence with abruption is 10%)

~*Abruption sufficient to cause fetal death results in a ~30% incidence of DIC?

1. immediate steep trendelenburg or knee chest position
2. manually push baby back up to get it off cord
3. C/S ASAP under GA!!!!!!!!!!!!!!!!!!

aortic stenosis

R to L shunts

Primary pulm HTN

What are Norms during pregnancy:

fibrinogen

platelet count

TT

PT

PTT

 What change do you see with DIC? 

fibrinogen 400-650mg/dl

platelets 150,000-300,000/mm

TT 15-20 secs

PT 10-12 sec

PTT 35-50 sec

ALL COUNTS ↓ AND ALL TIMES ↑