Postpartum Hemorrhage




Keywords

coagulopathy, major obstetric hemorrhage, postpartum hemorrhage (PPH), resuscitation

 




Case Synopsis


A 29-year-old woman, gravida 4, para 2, has been delivered of a 4200-g infant. Her labor had been augmented after high maternal temperatures and foul-smelling liquor. The anesthesiologist is called 2 hours after delivery of the placenta when the patient is noted to be increasingly hypotensive, tachycardic, and pale. On arrival, the anesthesiologist is informed that she has had a heavier-than-normal lochia resulting in a slow but persistent loss per vaginum.




Problem Analysis


Definition


Primary postpartum hemorrhage (PPH) has been defined as the loss of 500 mL or more of blood within 24 hours of delivery. PPH can be minor (500 to 1000 mL) or major (>1000 mL). Major can be further divided into moderate (1000 to 2000 mL) or severe (>2000 mL).


Most of the cases that cause morbidity or mortality or that present challenges in management have a blood loss greater than 1000 mL.


Although primary PPH is the most common form of obstetric hemorrhage, secondary PPH should not be forgotten. This is defined as abnormal or excessive bleeding from the birth canal between 24 hours and 12 weeks postnatally.


Recognition


PPH occurs in as many as 10% of deliveries. Blood loss may be obvious, such as per vaginum or loss from the surgical wound. However, it can also be concealed and contained within the uterus, soft tissues, or peritoneum. The patient may exhibit the following:




  • Anxiety, confusion, or unresponsiveness



  • Hypotension



  • Tachycardia (beware of patients on β-blockers who may have a normal pulse or bradycardia)



  • Poor peripheral perfusion



  • Oliguria



  • Unexplained metabolic acidosis



  • High ongoing fluid requirement to maintain blood pressure



Risk Assessment


Most patients with PPH will have no identifying risk factors. The risk factors are stated in Tables 72.1 and 72.2 and may result in direct blood loss or coagulation failure. Other risk factors include the following:




  • Polyhydramnios



  • Precipitous labor



  • Augmented labor



  • High parity



  • Use of tocolytic agents



  • Inhalational anesthetics at high concentrations



TABLE 72.1

Major Risk Factors for Postpartum Hemorrhage















Antenatal Presentation Approximate Odds Ratio for PPH (99% CI)
Placental abruption
Placenta previa
Multiple pregnancy
Preeclampsia/gestational hypertension
Previous PPH
Ethnicity
Obesity (BMI >35)
Macrosomia (>4 kg)
Anemia (hemoglobin <90 g/L)
Age >40
13 (7.61–12.9)
12 (7.17–23)
5 (3.0–6.6)
4
3
2 (1.48–2.17)
2 ( 1.24–2.17)
2 (1.38–2.60)
2 (1.63–3.15)
1.4 (1.16–1.74)
Factors That Become Evident During Labor
Cesarean section, emergency
Cesarean section, elective
Induction of labor
Retained placenta
Mediolateral episiotomy
Operative vaginal delivery
Prolonged labor (12 hours)
Pyrexia in labor
4 (3.28–3.95)
2 (2.18–2.80)
2 (1.67–2.96)
5 (3.36–7.87)
5
2 (1.38–2.60)
2
2

BMI, Body mass index; CI, confidence interval; PPH, postpartum hemorrhage.


TABLE 72.2

Relationship Between Etiology of Postpartum Hemorrhage and Predisposing Factors



















Etiology Predisposing Factors
Uterine atony Multiple gestation, macrosomia, polyhydramnios, chorioamnionitis, prolonged labor, precipitous labor, augmented labor, multiparity, use of tocolytics, use of potent inhalational anesthetics
Retained placenta Prior history of retained placenta, second-trimester delivery, abnormal placentation
Trauma Precipitous delivery, instrumented delivery, macrosomia
Uterine inversion Uterine atony, inappropriate umbilical cord traction, uterine anomalies, abnormal placentation


The most common cause of PPH is uterine atony. At term, blood flow through the placental vasculature is approximately 600 mL/min. After delivery, the primary mechanism that controls blood loss is contraction of the uterine myometrium. This tamponades disrupted blood vessels at the former placental site. Failure of this mechanism can result in massive and rapid blood loss.


Retained placenta is also a common cause of both early and delayed PPH, although not all cases result in significant blood loss. Retained placental fragments may be unrecognized and thus bleeding may be insidious. Patients who have had a prior retained placenta or who deliver well before term are likely to be affected.


Trauma associated with delivery can result in PPH and should be considered in all postpartum patients with continued blood loss despite a firm, contracted uterus. Traumatic bleeding can occur at the following sites:




  • Vagina



  • Cervix



  • Uterus (poor handling during cesarean section, disrupted sutures)



  • Perineum (laceration or episiotomy)



  • Other structures—tearing of the broad ligament, ovarian artery disruption



Uterine inversion is a rare cause of PPH but can be catastrophic. It should be suspected in any case of PPH when there is significant hypotension.


Implications


Patient outcome depends on early recognition, the rate and severity of blood loss, and timely anesthetic or obstetric intervention. It is worth remembering that PPH is a major cause of morbidity and remains one of the top five causes of maternal death in both developed and developing countries.

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Feb 18, 2019 | Posted by in ANESTHESIA | Comments Off on Postpartum Hemorrhage
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