Transcript 05._Postpartum_Hemorrhage

POSTPARTUM HEMORRHAGE “PPH”
Postpartum hemorrhage is defined as blood loss in
excess of 500 mL at the time of vaginal delivery.
There is normally a greater blood loss following
delivery by cesarean section; therefore, blood loss in
excess of 1000 mL is considered a postpartum
hemorrhage in such patients.
The excessive blood loss usually occurs in the immediate
postpartum period but can occur slowly over the first 24
hours”Primary post partum hemorrhage”.
Delayed postpartum hemorrhage can occasionally
occur, with the excessive bleeding commencing more
than 24 hours after delivery” Secondary PPH”. This is
usually a result of subinvolution of the uterus and
disruption of the placental site "scab" several weeks
postpartum or of the retention of placental fragments that
separate several days after delivery.
Postpartum hemorrhage occurs in about 4% of
deliveries.
Etiology
Most of the blood loss occurs from the myometrial
spiral arterioles and decidual veins that previously
supplied and drained the intervillous spaces of the
placenta.
As the contractions of the partially empty uterus cause
placental separation, bleeding occurs and continues
until the uterine musculature contracts around the
blood vessels and acts as a physiologic-anatomic
ligature.
The four T’s’
*Tone
Atony (over-distension/exhaustion/infection/distortion)
*Tissue
Retained POC
*Trauma
genital tract trauma (inversion/rupture/lacerations)
*Thrombin
Coagulation abnormalities (hereditary/acquired)
Failure of the uterus to contract after placental separation (uterine
atony) leads to excessive placental site bleeding. Other causes of
postpartum hemorrhage are list below.
Causes of postpartum hemorrhage
1-Uterine atony
2- Genital tract trauma
3- Retained placental tissue
4- Low placental implantation
5- Uterine inversion
6- Coagulation disorders
Abruptio placentae ◦
Amniotic fluid embolism ◦
Retained dead fetus ◦
Inherited coagulopathy ◦
UTERINE ATONY
The majority of postpartum hemorrhages (75% to 80%) are due to
uterine atony. The factors predisposing to postpartum uterine atony are
shown below;
*Factors predisposing to postpartum uterine atony;
Overdistention of the uterus
Multiple gestations
Polyhydramnios
Fetal macrosomia
Prolonged labor
Oxytocic augmentation of labor
Grand multiparity (a parity of 5 or more)
Precipitous labor (one lasting <3 hr)
Magnesium sulfate treatment of preeclampsia
Chorioamnionitis
Halogenated anesthetics
Uterine leiomyomata
GENITAL TRACT TRAUMA
Trauma during delivery is the second most common cause of
postpartum hemorrhage. During vaginal delivery, lacerations of
the cervix and vagina may occur spontaneously, but they are more
common following the use of forceps or a vacuum extractor.
The vascular beds in the genital tract are engorged during
pregnancy, and bleeding can be profuse.
Lacerations are particularly prone to occur over the perineal body,
in the periurethral area, and over the ischial spines along the
posterolateral aspects of the vagina. The cervix may lacerate at
the two lateral angles while rapidly dilating in the first stage of
labor.
Uterine rupture may occasionally occur. At the time of
delivery by low transverse cesarean section, an inadvertent
lateral extension of the incision can damage the ascending
branches of the uterine arteries; an extension inferiorly can
damage the cervical branches of the uterine artery.
Continued vaginal bleeding with a contracted uterus is either due
to retained placenta/membrane/clot or due to trauma and needs
to be managed actively while the patient is stable.
RETAINED PLACENTAL TISSUE
Normally, a layer of fibrinoid material, called Nitabuch's
layer, is found at the base of the placenta. When the partially
empty uterus contracts, the placenta cleanly separates through
this layer. If the placental anchoring villi grow down into the
myometrium and disrupt this fibrinoid layer, placental
separation will be incomplete or may not occur at all.
In about half of the patients with delayed postpartum
hemorrhage, placental fragments are present when uterine
curettage is performed with a large curette.
LOW PLACENTAL IMPLANTATION
Low implantation of the placenta can predispose to postpartum
hemorrhage because the relative content of musculature in the
uterine wall decreases in the lower uterine segment, which may
result in insufficient control of placental site bleeding.
COAGULATION DISORDERS
Peripartum coagulation disorders are high-risk factors for
postpartum hemorrhage but fortunately are quite rare. Patients
with coagulation problems, such as occur with thrombotic
thrombocytopenic purpura, amniotic fluid embolism, abruptio
placentae, idiopathic thrombocytopenic purpura, or von
Willebrand's disease, may develop postpartum hemorrhage
because of their inability to form a stable blood clot in the
placental site.
DIFFERENTIAL DIAGNOSIS
Identification of the cause of postpartum hemorrhage requires a
systematic approach. The fundus of the uterus should be palpated
through the abdominal wall to determine the presence or absence
of uterine atony. Next, a quick but thorough inspection of the
vagina and cervix should be performed to ascertain whether any
lacerations may be compounding the bleeding problem. Any
uterine inversion or pelvic hematoma should be excluded during
the pelvic examination. If the cause of bleeding has not been
identified, manual exploration of the uterine cavity should be
performed, under general anesthesia if necessary. With fingertips
together, a gloved hand is slipped through the open cervix, and the
endometrial surface is palpated carefully to identify any retained
products of conception, uterine wall lacerations, or partial uterine
inversion. If no cause for the bleeding is found, a coagulopathy
must be sought.
MANAGEMENT OF POSTPARTUM HEMORRHAGE
The first steps toward good management are the identification
of patients at risk for postpartum hemorrhage and the institution
of prophylactic measures during labor to minimize the
possibility of maternal mortality.
Patients with any predisposing factors for postpartum
hemorrhage, including a history of postpartum hemorrhage,
should be screened for anemia and atypical antibodies to ensure
that an adequate supply of type-specific blood is on hand in the
blood bank.
An intravenous infusion via a large-bore needle or catheter
should be commenced prior to delivery, and blood should be
held in the laboratory for possible crossmatching.
**2 major components
Resuscitation
Identification and management of the underlying
cause(s)
**Simultaneously and systematically
During the diagnostic workup of an established hemorrhage,
**the patient's vital signs must be monitored closely.
Hypotension is a very late sign and tachycardia, peripheral
perfusion, skin colour and urine output should be noted.
If the lower segment of the uterus or the cervix fills up with blood
or clot it can cause vagal stimulation producing a bradycardia –
this can mislead when there is no visible vaginal bleeding and a
vaginal examination should be done.
**Four units of packed red blood cells must be typed and crossmatched.
**Intravenous crystalloids (such as normal saline or lactated
Ringer's solution) infused to restore intravascular volume.
Resuscitation with normal saline usually requires a volume of
three times the estimated blood loss.
UTERINE ATONY
If uterine atony is determined to be the cause of the
postpartum hemorrhage, continuous massage of the uterus
with a rapid continuous intravenous infusion of dilute oxytocin
(40 to 80 U in 1 L of normal saline) should be given to increase
uterine tone.
If the uterus remains atonic and the placental site bleeding
continues during the oxytocic infusion, ergonovine maleate or
methylergonovine, 0.2 mg, may be given intramuscularly. The
ergot drugs are contraindicated in patients with hypertension,
because the pressor effect of the drug may increase blood pressure
to dangerous levels.
Analogues of prostaglandin F2α given intramuscularly are quite
effective in controlling postpartum hemorrhage caused by
uterine atony. The 15-methyl analogue (Hemabate) has a more
potent uterotonic effect and longer duration of action than the
parent compound. The expected time of onset of the uterotonic
effect when the 15-methyl analogue (0.25 mg) is given
intramuscularly is 20 minutes, whereas when injected into the
myometrium it may take up to 4 minutes.
Failing these pharmacologic treatments, a bimanual compression
and massage of the uterine corpus may control the bleeding
and cause the uterus to contract.
Uterine massage
Bimanual compression
Although packing the uterine cavity is not widely practiced, it
may occasionally control postpartum hemorrhage and obviate the
need for surgical intervention. The vital signs, hematocrit, and
fundal height should be monitored frequently while the packing
is in place, because continued bleeding will not be initially
evident through the packing. The packing may be removed in 1
to 24 hours. Usually, the bleeding will be controlled.
Recently rather than using a gauze pack, an inflatable balloon
has the advantage of being quick and expandable. Various
balloon catheters have been reported for this technique including
the Sengstaken-Blakemore, but the urological Rusch balloon
catheter is cheaper and effective.
Whatever is used to pack the uterus, antibiotic cover should
be given for the procedure and until the pack/balloon is removed;
and similarly the bladder should be catheterized
until the pack is removed.
If uterine bleeding persists in an otherwise stable patient, she
could be transported to the angiocatheterization laboratory,
where radiologists can place an angiocatheter into the uterine
arteries for injection of thrombogenic materials to control
blood flow and hemorrhaging.
Operative intervention is a last resort. If the patient has
completed her childbearing, a supracervical or total
abdominal hysterectomy is definitive therapy for intractable
postpartum hemorrhage caused by uterine atony.
Aortic compression If bleeding is out of control and the
anaesthetist needs to stabilize the patient, it is worth trying
aortic compression while waiting for senior or specialist help to
arrive. The effect is dramatic and can be life-saving.
**If reproductive potential is important to the patient,then
Brace suture The B-Lynch brace suture, first described in 1997
can avoid hysterectomy in cases of bleeding from uterine atony. It
aims to exert longitudinal lateral compression to the uterus
combined with a tamponade effect
ligation of the uterine arteries adjacent to the uterus will lower the
pulse pressure distal to the ligatures. This procedure is more
successful in controlling uterine placental site hemorrhage and is
easier to perform than bilateral hypogastric artery “internal iliac
artery” ligation.
Cell salvage This technique of contemporary peri-operative
autologous blood salvage and retransfusion. It has an excellent
safety record, is acceptable to Jehovah’s witnesses and avoids the
risks associated with homologous blood transfusion. With the
impending blood shortages and the risk of post-transfusion
infection, it is likely to be adopted in an increasing number of
obstetric units.
Activated factor VIIa The use of this novel, prohaemostatic agent
has potential for treating severe obstetric haemorrhage. Its use is
limited to patients with complicated coagulation disorders and
should only be considered in life-threatening bleeding.
GENITAL TRACT TRAUMA
When postpartum hemorrhage is related to genital tract
trauma, surgical intervention is necessary. Repair of
genital tract lacerations requires the implementation of an
important principle: The first suture must be placed well
above the apex of the laceration to incorporate any
retracted bleeding arterioles into the ligature. Repair of
vaginal lacerations requires good light and good exposure,
and the tissues should be approximated without dead
space. A running lock suture technique provides the best
hemostasis.
**Cervical lacerations need not be sutured unless they
are actively bleeding .
Large, expanding hematomas of the genital tract require
surgical evacuation of clots and a search for bleeding
vessels that can be ligated, then packed for
hemostasis.
Stable hematomas can be observed and treated
conservatively. A retroperitoneal hematoma generally
begins in the pelvis. If the bleeding cannot be controlled
from a vaginal approach, a laparotomy and bilateral
hypogastric artery ligation may be necessary.
Cervical tear suturing