Obstetric Emergencies and Anesthetic Management

Co-ordinator: Dr.Navab Singh(M.D.)Speaker: Dr. Uday

OBSTETRIC EMERGENCIES• Maternal

– APH– PPH– Retained placenta– Rupture uterus

• Fetal distress– Cord prolapse– Hand prolapse– Obstructed labor(large head)– Uteroplacental insufficiency– Shoulder dystocia– Vaginal breech delivery (head entrapment)

HEMORRHAGE

• PREPARTUM/INTRAPARTUM:

– Placenta previa– Placental abruption– Placenta accreta/increta/percreta– Uterine rupture

• POSTPARTUM:

– Retained placenta– Uterine atony– Uterine inversion– Birth trauma/laceration

PLACENTA PREVIA

• 1 in 200-250deliveries.• Cardinal symptom of placenta previa is painless vaginal bleeding.• first episode usually stops spontaneously. • Bleeding typically manifests at approximately 32week of gestation, when the lower

uterine segment begins to form. • When this diagnosis is suspected, the position of the placenta needs to be

confirmed via ultrasonography or radioisotope scan.• Placenta previa occurs when implantation of the placenta is low in the uterus;• it is either overlying or encroaching on the cervical os.• Placenta previa is present in approximately 0.6% of all pregnancies.• It categorized as :

– complete if the placenta completely covers the os, – partial if there is some encroachment on the os by the placenta, – marginal if the placenta is not covering but is close to the internal os

Conti……• ETIOLOGY:• Unknown• Previous placenta previa• Advanced maternal age• The condition is more common in multiparous women, and it is especially common

in women who have had a previous cesarean section. • Typically, in contrast with placental abruption, • placenta previa is characterized by painless vaginal bleeding in the third trimester.

• Management :• Bleeding may stop spontaneously, in which case conservative management is

recommended. • Urgent/emergent cesarean delivery for active or persistent bleeding or fetal

distress. • Except for a patient with a marginal previa who might elect. vaginal delivery, other

patient will be delivered by cesarean section.

Conti..

• Anesthetic Management • Anesthetic management is dependent on the obstetric plan and the

condition of the parturient.• Preoperative • Mild to moderate blood loss is well tolerated by the patient .• Adequate volume resuscitation is thus paramount to the patient's care. • All patients should be typed and cross-matched to ensure continuous availability of

packed red blood cells and, if needed, blood products.

• Intraoperative • Parturients with a total or partial previa will deliver by cesarean section. • Anesthetic management will depend on maternal and fetal status and the urgency

of the surgery.

Conti...

• If patient has not had recent bleeding and is scheduled electively, regional anesthesia is preferred.

• Large-bore intravenous access should be established as the patient is at greater risk of intraoperative bleeding.

• Cross-matched blood should be immediately available.• If hemorrhage necessitates emergency delivery, general anesthesia is the

anesthetic technique of choice. • Ketamine and etomidate are the preferred induction agents in the hypovolemic

patient. Maintenance of anesthesia will be determined by the hemodynamic status of the mother.

Placental abruption

• Placental abruption, a partial or complete separation of the placenta before delivery of the fetus.

• occur in 1.3% to 1.6% of pregnancies.

• Preexisting conditions such as – chronic hypertension, – pregnancy-induced hypertension, – preeclampsia, – maternal cocaine use, – excessive alcohol intake, – smoking, – previous history of abruptionPlacental abruption may be manifested as vaginal bleeding and uterine

tenderness

conti…

• Vaginal bleeding-Classical presentation• May not always be obvious • 3000 ml or more blood can be sequestered behind placenta in concealed bleeding • Uterus can’t selectively constrict abrupted area• Decreased placental area-fetal asphyxia• 1 in 750 deliveries-fetal death• Severe neurological damage in some surviving infants• Upto 90% abruptions-mild to moderate• Problems: Hemorrhage, Consumptive coagulopathy, Fetal hypoxia, Prematurity• Low fibrinogen/ Factor V, Factor VII and platelets and increased fibrin split products

Treatment • Definitive treatment of abruptio placentae is delivery of the fetus and placenta.

Delivery may be vaginal if the abruption is not jeopardizing maternal or fetal well-being. Otherwise, delivery is by cesarean section.

Conti....

Anesthetic Management • If maternal hypotension is absent, clotting studies are acceptable, and there is no evidence

of fetal distress due to uteroplacental insufficiency, • epidural analgesia is useful for providing analgesia for labor and vaginal delivery. • When magnitude of placental separation and resulting hemorrhage are severe, emergency

cesarean section is necessary.• most often, general anesthesia is used, as regional anesthesia in a hemodynamically

unstable.• Anesthetic management is similar to that employed with placenta previa. Blood and blood

products should be readily available due to the risk of bleeding and DIC.• It is not uncommon for blood to dissect between layers of the myometrium after

premature separation of the placenta. • As a result, the uterus is unable to contract adequately after delivery, and postpartum

hemorrhage occurs. • Uncontrolled hemorrhage may require an emergency hysterectomy. • Bleeding may be exaggerated by coagulopathy, in which case infusion of fresh frozen

plasma and platelets may be indicated to replace deficient clotting factors. • Clotting parameters usually revert to normal within a few hours after delivery of the

neonate.

Placenta Accreta

• Definition: abnormal development and implantation of the placenta. Or abnormally adherent to the myometrium.

• Placenta accreta is an adherent placenta that has not invaded the myometrium. • placenta increta, the placenta has invaded the myometrium• placenta percreta is invasion through the serosa.• Incidence: 1 in 2000 deliveries but higher in

– placenta previa – prior C-section

Conti..

Signs and Symptoms • Retained placenta and postpartum hemorrhage occur in patients with placenta

accreta.• Treatment • The majority of cases require cesarean hysterectomy.

Anesthetic Management • Preoperative • Significant hemorrhage should be anticipated and thus at least two large-bore

intravenous catheters placed. arterial catheter should be considered. • Packed red blood cells should be immediately available and blood products readily

available. • use of a cell saver should be considered after delivery.

Conti..

• preoperative interventional radiography consultation should be obtained as arterial embolization may reduce intraoperative blood loss.

• Intraoperative • Intraoperative management of a patient at risk of hemorrhage and/or cesarean

hysterectomy is controversial. • Many believe all patients should received general anesthesia (as discussed for

patients with a placenta previa). • Others argue that if needed, a cesarean hysterectomy can be performed under

epidural anesthesia.

UTERINE RUPTURE

• Prepartum, intrapartum or postpartum

• ETIOLOGY:– Prior cesarean delivery especially classical cesarean scar– Rupture of myomectomy scar– Precipitous labor– Prolonged labor with cephalopelvic disproportion– Excessive oxytocin stimulation– Abdominal trauma– Grand multiparity – Iatrogenic– Direct uterine trauma-forceps or curettage

Conti..

Signs and Symptoms • Uterine rupture may present with severe abdominal pain, often referred to the

shoulder due to subdiaphragmatic irritation by intra-abdominal blood, maternal hypotension, and disappearance of fetal heart tones.

Diagnosis • An ultrasound examination is useful in making the diagnosis of uterine rupture.

Visual examination of the uterus at cesarean delivery will detect rupture or dehiscence. Manual examination with vaginal delivery will detect dehiscence as well.

Treatment • Uterine rupture with maternal and/or fetal distress mandates immediate

laparotomy, delivery, and surgical repair or hysterectomy.

Prognosis • Maternal mortality is rare. Fetal mortality is approximately 35%.

Anesthetic Management • Anesthetic management is similar to that for the unstable patient with placenta

previa

Uterine atony

• Uterine atony is the most common cause of postpartum hemorrhage, and it is caused by ineffective uterine muscle contraction in the postpartum period.

• Risk factors include prolonged labor, an overdistended uterus (macrosomia or multiple births), infection, grand multiparity, and administration of drugs that relax the uterus (halogenated anesthetics, β-sympathomimetic agonists, and magnesium sulfate).

• Surgical compression suturing (“B-Lynch suture”) is an important technique for treating postpartum hemorrhage associated with uterine atony and may avoid the need for cesarean hysterectomy.

Uterine Atony

Medication

Class Administration

Dosing Side effect Comments

Oxytocin Neurohypophyseal hormone

Infusion Up to 40 IU/l

Hypotension with rapid infusion

Initial therapy

Methylergonovine

Ergot alkaloid

Intramuscular

0.4 mg IM repeat once

Hypertension

Sustained increase in uterine tone

Carboprost

Prostaglandin

Intramuscular intramyometrial

0.25mg IM repeat up to 1.0mg total

Systemic and pulmonary hypertension, bronchospasm

Never administer intravenously

RETAINED PLACENTA

• The placenta is said to be retained if it has not been delivered within 30 - 60 minutes of the birth.

• occurs in approximately 1% of vaginal deliveries.• The following are risk factors:

– Previous retained placenta– Previous injury to uterus– Pre-term delivery– Induced labour– Multiparity

• Management• Manual removal of the placenta(MRP) is the standard treatment and is usually

carried out under anaesthesia (or more rarely, under sedation and analgesia).

Comparison of general anaesthesia, regional anaesthesia and sedation

Technique Advantages Disadvantages

GA Dose-dependent uterine

relaxation by volatile agent.

Risks of general anaesthesia e.g. airway compromise, aspiration, anaphylaxis.

Spinal Rapid establishment of

profound analgesia.

Avoids risks of GA.

Potential for sudden hypotension if extent of haemorrhage not recognised.

Epidural Good if already in situ

Takes time to establish de novo

Sedation Quick and easy Poor uterine relaxation Unprotected airway: risk of aspiration if

overdose

Conti..

General anaesthesia and sedation• A rapid sequence induction should be performed following adequate pre-

oxygenation. • If woman is in shock, etomidate or ketamine are preferable to thiopental or

propofol as induction agents. • Equipotent doses of all the volatile agents depress uterine contractility . • Electrocardiogram, blood pressure and end-tidal CO2/vapour tension should be

monitored .• Fentanyl, midazolam and ketamine can all be given by titrated i.v. increments.

Regional anaesthesia• Spinal anaesthesia avoids the risks associated with general anaesthesia. 2.0 - 2.5ml

of hyperbaric bupivacaine 0.5% should ensure cold sensation blockade to T6 and maternal intra-operative comfort. Hypotension secondary to regional anaesthesia is likely to be related to maternal blood loss rather than block height.

• A low-dose spinal anaesthetic regimen comprising 1.5ml 0.25% plain bupivacaine and fentanyl 25micrograms has been shown to provide satisfactory operative conditions. Motor function preserved, and maternal satisfaction is high.

Uterine Inversion

• Uterine inversion is a rare cause of postpartum hemorrhage .• uterine fundus inverts through the cervix into the vagina.• Hypotension usually results before significant blood loss has occurred.

Treatment :-• fluid therapy for the mother and restoration of the uterus to its normal position. • Uterine relaxation may be necessary to replace the uterus; β-sympathomimetic

agents, magnesium, and nitroglycerin .• choice of agent may be dependent on the mother's hemodynamic stability. • For example, in the case of profound maternal hypotension, magnesium sulfate

may be a better choice than nitroglycerin. • Should initial efforts to replace the uterus prove unsuccessful, rapid-sequence

induction with cricoid pressure and endotracheal intubation should be undertaken. The use of volatile agents will also cause uterine relaxation, thereby assisting the obstetrician in replacing the uterus.

BIRTH TRAUMA/LACERATIONS

• Lesions range from laceration to retroperitoneal hematoma requiring laparotomy• Can result from difficult forceps delivery/• Precipitous vaginal delivery/• Malpresentation of fetal head (OP)/• Laceration of pudendal vessels/• Clinical presentation of postpartum bleeding with contracted uterus• Saddle (SAB)/Epidural/or GA given to repair of trauma.

Hypovolemic Shock

• Circulatory failure leading to inadequate perfusion and delivery of oxygen to vital organs.

• Blood Pressure is often used as an indirect estimator of tissue perfusion.

• Oxygen delivery is an interaction of Cardiac Output, Blood Volume, Systemic Vascular Resistance.

• Causes-– Trauma– Blood Loss– Occult fluid loss (GI)– Burns– Pancreatitis– Sepsis (distributive, relative hypovolemia)

Class I Class II Class III Class IV

Blood loss (ml) ≤750 750-1500 1500-2000 >2000

% blood loss ≤15 15-30 30-40 >40

Heart rate (bpm) <100 >100 >120 >140

SBP N N ↓ ↓

Pulse pressure N or ↑ ↓ ↓ ↓

Cap Refill < 3 sec > 3 sec >3 sec or absent

absent

Resp rate/ min 14-20 20-30 30-40 <35

Urine output (ml/hr)

>30 20-30 5-15 Negligible

Mental status Slightly anxious

Mildly anxious Anxious and confused

Confused and lethargic

CLASSIFICATION OF HEMORRHAGIC SHOCK

Pathophysiology Clinical Manifestation

Mild(<20% of blood volume lost)

Decreased peripheral perfusion only of organ able to withstand prolonged ischemia (skin, fat, muscle, and bone)

Pt complaint of feeling coldPostural hypotension and tachycardiaCool, pale, and moist skinConcentrated urine

Moderate(20-40% of blood volume lost)

Decreased central perfusion of organs able to tolerate only brief ischemia(kidney, liver)Metabolic acidosis present

ThirstSupine hypotension and tachycardia(variable)Oligouria and anuria

Severe(>40% of blood volume lost)

Decreased perfusion of heart and brainSevere metabolic acidosisRespiratory acidosis possibly present

Agitation, confusion, or obtundationSupine hypotension and tachycardia invariabaly presentRapid, deep respiration

Fluid Resuscitation of Shock

Crystalloid Solutions • Normal Saline• Lactated Ringers Solution• DNS• Require 3:1 replacement of volume loss• e.g. estimate 1 L blood loss, require 3 L of crystalloid to replace volume. • Intravenous fluids are recommended in most types of shock (1-2 liter normal saline

bolus over 10 minutes or 20ml/kg in a child) If the person remains in shock after initial resuscitation packed red blood cell should be administered to keep the hemoglobin greater than 10 gms/dl.

• Hemorrhagic shock the current evidence supports limiting the use of fluids for penetrating thorax and abdominal injuries allowing mild hypotension to persist (known as permissive hypotension).

• Targets include a mean arterial pressure of 60 mmHg, a systolic blood pressure of 70-90 mmHg. or until their adequate peripheral pulses.

Conti…

Colloid Solutions• Pentastarch• Albumin 5% • Red Blood Cells• Fresh Frozen Plasma• Replacement of lost volume in 1:1 ratio

Oxygen Carrying Capacity• Only RBC contribute to oxygen carrying capacity (hemoglobin)• Replacement with all other solutions will

o support volumeo Improve end organ perfusiono Will NOT provide additional oxygen carrying capacity.

RBC Transfusion BC Red Cell Transfusion Guidelines recommend transfusion only to keep Hgb >7

g/dL unless– Comorbid disease necessitating higher transfusion trigger (CAD, pulmonary

disease, sepsis)– Hemodynamic instability despite adequate fluid resuscitation. – PRBC’s at 5-10 cc/kg.

Estimating the resuscitating volumeNormal blood volume(BV)= 66ml/kg in male and 60ml/kg in femaleVolume deficit(VD)= BV ˣ % of loss blood volumeDetermine resuscitating volume(RV)= VD ˣ1.5(colloids) =VD ˣ 4(crystalloid)

Definition of massive transfusion

• The replacement of patient’s entire blood volume in a 24-hour period. or• The transfusion of more than 20u of whole blood or 40u of PRBC. or• The replacement of over 50% of circulating blood volume in 3 hour or less or• Loss of blood or more than 150ml/min

Blood component– Whole blood: 250ml. containing PRBC 1u, FFP 1u and 30ml preservatives.– PRBC: ~100ml. Hct 70~80%. PRBC 1u can increase Hb 0.5 (Hct 1.5)– FFP: ~125ml. Containing coagulation factor, protein and plasma.– PLT: ~25ml. PLT 12u can increase PLT 60000.

INDICATIONS FOR BLOOD COMPONENT Component Indication Usual starting dose

Whole blood

RBC

Platelets

Fresh frozen plasma

Cryoprecipitate

Blood loss > 1500ml

Blood loss < 1000ml,Replacement of oxygen-carrying capacity

Thrombocytopenia or thrombasthenia with bleeding

Documented coagulopathy

Coagulopathy with low fibrinogen

better than PRBC + FFP.

Packed 2–4 Units

2–6 Units

10-15 Units

10–20 Units

Complications of Blood Transfusion• O2 Transport

– Shift to left in O2-Hb dissociation curve so RBC's have increased affinity for oxygen and there is less available to tissues.

– Warm blood and avoid other things that shift O2-Hb dissociation curve to the left such as alkalosis (bicarb) and hypothermia.

• Transfusions Reactions • Citrate Intoxication and Hyperkalemia • Hypothermia • Acid-Base Disturbances• Microaggregates • Infectivity-Hepatitis, HIV, CMV, Syphilis • Dilutional Coagulopathy• Volume overload.

Complication Mechanisms Management

Coagulopathy •Dilution•Depletion•Disseminated Intravascular Coagulation (DIC)

•Monitor patient coagulation parameters If INR/aPTT is ≥ 1.5-2.0 consider transfusing FFP•If fibrinogen is < 1.0 g/L consider transfusing cryoprecipitate

Thrombocytopenia •Dilution•Depletion•DIC

•Monitor patient platelet counts If platelet count falls below 50 000/cu consider transfusing platelets

Hypothermia •Infusion of cold IV fluids and blood products

•Monitor patient temperature Consider warming the patient and/or blood components

Hypocalcemia •Calcium chelation by citrate •Monitor the patient for arrhythmias and calcium levels Initiate intravenous calcium therapy

Hyperkalemia •Rapid transfusion of older cells (potassium concentration increases in RBC units with storage time)

Monitor patient electrolytes and ECG; consider treatment to lower serum potassium

Metabolic Acidosis •Shock•Acid pH of blood components

Monitor patient pH, and correct imbalance

THANKS FOR YOUR ATTENTION!!

Class I Class II Class III Class IV

Blood loss (ml) ≤750 750-1500 1500-2000 >2000

% blood loss ≤15 15-30 30-40 >40

Heart rate (bpm) <100 >100 >120 >140

SBP N N ↓ ↓

Pulse pressure N or ↑ ↓ ↓ ↓

Cap Refill < 3 sec > 3 sec >3 sec or absent

absent

Resp rate/ min 14-20 20-30 30-40 <35

Urine output (ml/hr)

>30 20-30 5-15 Negligible

Mental status Slightly anxious

Mildly anxious Anxious and confused

Confused and lethargic

Treatment 1 – 2 L crystalloid, + maintenance

2 L crystalloid, re-evaluate

2 L crystalloid, re-evaluate, replace blood loss 1:3 crystalloid, 1:1 colloid or blood products. Urine output >0.5 mL/kg/hr

CLASSIFICATION OF HEMORRHAGIC SHOCK