2. INCIDENCE, MORBIDITY,
AND MORTALITY
• Maternal mortality has declined to almost
negligible levels
the greater use of neuraxial anesthesia,
the use of antacids, histamine-2(H) receptor
antagonists, and/or proton-pump inhibitors,
use of rapid-sequence induction of general
anesthesia,
improvement in the training of anesthesia
providers and establishment and enforcement of
nil per os policies.
3. Effects of Pregnancy on
Gastric Function
• Gastroesophageal reflux.
• Integrity of the lower esophageal sphincter
alters the anatomic relationship
raises intragastric pressure, and
limits the ability of LOS to increase tone.
• Progesterone, which relaxes smooth muscle.
4. • Pregnant woman should be regarded as
having an incompetent lower esophageal
sphincter.
• Physiologic changes return to their
prepregnancy levels by 48 hours after delivery.
5. • Presence of other associated problems in this group of
patients (e.g., hiatal hernia or difficult airway).
• Gastric emptying becomes delayed as labor advances.
• Parenteral opioids cause a significant delay in gastric
emptying.
• Continuous epidural infusion of low-dose local
anesthetic with fentanyl does not appear to delay
gastric emptying until the total dose of fentanyl
exceeds 100 µg.
• The plasma concentration of the gastrointestinal
hormone motilin is decreased during pregnancy.
6. RISK FACTORS FOR ASPIRATION
PNEUMONITIS
• Mendelson divided aspiration pneumonitis into two
types: liquid and solid.
• Aspiration of solids could result in asphyxiation.
• Aspiration of liquids were more severe clinically and
pathologically when the liquid was highly acidic .
• morbidity and mortality of aspiration depend on the
following three variables:
the chemical nature of the aspirate,
the physical nature of the aspirate, and
the volume of the aspirate.
7. • Aspirates with a pH less than 2.5 cause a
granulocytic reaction .
• Aspiration of small volumes of neutral liquid
results in a very low rate of mortality.
• Aspiration of large volumes of neutral liquid
results in a high mortality rate-disruption of
surfactant by the large volume of liquid.
8. • Historically, anesthesia providers have
considered a non particulate gastric fluid with
a pH less than 2.5 and a gastric volume
greater than 25 mL (i.e., 0.4 mL/kg) as risk
factors for aspiration pneumonitis.
11. CLINICAL COURSE
• Patients who aspirate have brief period of
breathholding followed by tachypnea, tachycardia,and
a slight respiratory acidosis.
• chest x ray findings lag behind clinical signs -12 to 24
hours.
• In mild cases, alveolar infiltrates are seen in the
dependent portions of the lungs.
• In severe aspiration results in diffuse bilateral infiltrates
without signs of heart failure (i.e., engorged pulmonary
vasculature and/or enlarged cardiac silhouette) .
• These symptoms and signs may progress to satisfy the
Berlin Definition for ARDS
12.
13. Management of Aspiration
• Rigid Bronchoscopy and Lavage
• Antibiotics
• Treatment of Hypoxemia
• Corticosteroids
16. RECOMMENDATIONS FOR CESAREAN
DELIVERY
• For elective cesarean delivery,
oral administration of an H receptor antagonist
or a PPI at bedtime and again 60 to 120 minutes
before anesthesia.
• For emergency cesarean delivery under general
anesthesia,
30 mL of sodium citrate should be administered
ranitidine 50 mg and metoclopramide 10 mg
should be given intravenously when time allows.
17. Choice of Anesthesia
• Use of neuraxial anesthesia for cesarean delivery
is preferred unless contraindicated.
• Sellick Maneuver and Induction of Anesthesia
head should be fully extended
thumb and middle finger on either side of
the cricoid cartilage
cricoid pressure requires a force of 30 Newtons
18. Antepartum Hemorrhage
• Obstetric hemorrhage is the most common
cause of maternal mortality worldwide.
• The majority of hemorrhage-related adverse
outcomes are considered preventable.
19. MECHANISMS OF HEMOSTASIS
• Uterine contraction, stimulated by
endogenous oxytocic substances released
after delivery .
• Uterine tetany cleave the placenta from the
uterine wall through the layer of the uterine
decidua .
• uterine contraction constricts the spiral
arteries and placental veins spanning the
myometrium and supplying the placental bed.
20. Mechanisms of coagulation
• platelet aggregation and plug formation,
• Local vasoconstriction,
• Clot polymerization and
• fibrous tissue fortification of the clot. Platelet
• Activated platelets release adenosine diphosphate
(ADP), serotonin, catecholamines, and other factors
that promote local vasoconstriction and hemostasis
which activate the coagulation cascade.
• end result of the cascade is conversion of fibrinogen
fibrin and stabilization of the blood clot .
21. ANTEPARTUM HEMORRHAGE
• Antepartum vaginal bleeding may occur in as
many as 25% of pregnant women
• only a fraction of these patients experience life-
threatening hemorrhage.
• The majority of cases occur during the first
trimester.
• The causes of antepartum hemorrhage range
from cervicitis to abnormalities in placentation.
• The greatest threat of antepartum hemorrhage is
not to the mother.
22. Placenta Previa
• Definition-when the placenta implants in
advance of the fetal presenting part.
• Classification- total placenta previa,
partial placenta previa ,
marginal placenta previa.
23. • should be evaluated by an anesthesia provider on
arrival.
• Volume resuscitation should be initiated using a non–
dextrose-containing balanced salt solution (e.g.,
lactated Ringer’s, normal saline).
• intravenous catheter should be maintained if bleeding
is recurrent or imminent delivery is anticipated.
• Hemoglobin concentration measurement blood
typeand crossmatch, should be maintained.
• The use of lowerextremity sequential compression
devices may decrease the risk for venous
thromboembolism in patients on bed rest.
24. • Anesthetic Management
Double Setup Examination.
Cesarean Delivery
• the obstetrician may injure an anteriorly located placenta
during uterine incision.
• Second, after delivery, the lower uterine segment
implantation site, lacking uterine muscle compared with
the fundus, does not contract as well as the normal fundal
implantation site.
• Third, a patient with placenta previa is at increased risk for
placenta accreta, especially if there is a history of previous
cesarean delivery.
25. • The choice of anesthetic technique depends
• Indication and urgency for delivery,
• The severity of maternal hypovolemia,
• The obstetric history .
• epidural anesthesia was associated more
stable blood pressure after delivery and
lower transfusion rates and transfusion volumes
26. • Rapid-sequence induction of general
anesthesia is preferred technique for bleeding
patients.
• A low dose of induction agent is appropriate
in patients with severe hemorrhage,
• nitrous oxide can be reduced or omitted in
cases of severe maternal hemorrhage or fetal
compromise.
27. Placental Abruption
• Complete or partial separation of
the placenta from the decidua basalis
before delivery of the fetus.
• Maternal hemorrhage may be revealed by
vaginal bleeding or may be concealed behind
the placenta.
28. • Complications include hemorrhagic shock,
coagulopathy, and fetal compromise or
demise.
• Thromboplastic substances are released into
the central circulation, resulting in
consumptive coagulopathy and disseminated
intravascular coagulation (DIC).
29. Anesthetic Management
• Neuraxial anesthesia may be administered in
stable patients in whom intravascular volume
status is adequate and coagulation studies are
normal.
• General anesthesia is preferred for most cases of
urgent cesarean delivery.
• ketamine and etomidate may represent better
options for the patient with unknown or
decreased intravascular volume.
• Aggressive volume resuscitation is critical.
30. Anesthetic Management
• Insertion of an intra-arterial catheter may aid prompt
recognition of hypotension.
• Patients with abruption are at risk for persistent hemorrhage
after delivery from uterine atony or coagulopathy.
• Oxytocin should be infused promptly to prevent uterine atony.
• Experts recommend aggressive monitoring and early
replacement of coagulation factors, especially fibrinogen, to
minimize the developing coagulopathy.
• A minority of postpartum patients who need massive blood
volume and blood product replacement are best monitored
in a intensive care unit.
31. Uterine Rupture
• Rupture of the gravid uterus can be disastrous for both the
mother and the fetus.
• Rupture of a previous uterine scar may occur in the
absence of labor.
• Classical uterine incision scar (a vertical incision involving
the muscular uterine fundus) is associated with greater
morbidity and mortality than rupture of a low transverse
uterine incision scar because the anterior uterine wall is
highly vascular and may include the area of placental
implantation.
• Lateral extension of the rupture can involve the major
uterine vessels and is typically associated with massive
bleeding.
32. Anesthetic Management
• General anesthesia is often necessary, except
in stable patients with preexisting epidural
labor analgesia.
• Aggressive volume replacement.
• Invasive hemodynamic monitoring.
• Urine output monitoring.
33. Vasa Previa
• Definition: fetal vessels traverse the
fetal membranes ahead of the fetal
presenting part.
• Associated with a high fetal mortality rate.
• Ruptured vasa previa is a true obstetric
emergency that requires immediate delivery.
• Neonatal resuscitation requires immediate
attention to neonatal volume replacement
with colloid, balanced salt solutions, and blood.
34. • The choice of anesthetic technique depends
on the urgency of the cesarean delivery.
• General anesthesia is necessary for prompt
delivery.
