True Learn OB Flashcards
What proteins decrease in pregnancy? Which proteins increase in pregnancy?
Serum albumin concentration decreases during pregnancy because of plasma expansion. Many other serum constituents such as fibrinogen, transferrin, and globulins increase, most likely due to the hormonal changes secondary to the pregnant state.
What are the early signs of Amniotic Fluid Embolism?
What are the late signs of Amniotic Fluid Embolism?
What is the treatment for the baby?
Amniotic fluid embolism is characterized by an early stage with pulmonary vasospasm and right heart dysfunction or failure
Second stage (late) with pulmonary edema and left heart dysfunction or failure.
- Maternal coagulopathy (consumptive) occurs in the majority of cases.
Treatment = Emergency cesarean section is required if uterine hypertonus leads to fetal bradycardia and distress.
What is pre-eclampsia thought to be?
What are the core manifestations? (4)
Levels of TXA2 and Prostacyclin?
In preeclampsia, there is an elevation in thromboxane A2 levels and a decrease in prostacyclin levels leading to a primarily vasoconstricted state.
Preeclampsia is characterized by global vascular hyperreactivity
- intravascular volume depletion
- high systemic vascular resistance
- uterine vasoconstriction of the myometrium
- Decreased uterine and placental blood flow
In anti-phospholipid syndrome, what are the typical coagulation labs showing?
- PT is normal 2. aPTT is prolonged (elevated) - which is paradoxical
Carboprost
What is the full name?
Generic name?
Class?
Mechanism?
Indications?
Side Effects and contraindications?
Carboprost Tromethamine aka 15-methyl prostaglandin F2 alpha aka “Hemabate”
Class: Uterotonic (Stimulates uterine contraction)
Mechanism: - Increase in myometrial free calcium concentration
Indications:
- Uterine Atony
- Need to perform Internal Podalic Version
Contraindications:
- Pulmonary Hypertension
- Reactive airway disease (Asthma/COPD)
- Increased intrapulmonary shunt fraction
- Hypoxemia
What is the preferred anesthetic for a patient undergoing a cerclage?
Spinal Physiology:
Cervix → T10-L1 dermatomes (Ask OB attending) Vagina and Perineum → S2-S4 dermatomes
Indications: Spinal anesthesia with hyperbaric solution is the most appropriate anesthetic for a pregnant patient undergoing cervical cerclage as this method provides adequate sacral coverage for the mother without endangering the fetus.
Avoid general due to:
- Potential hemodynamic changes and placental insufficiency
- Coughing on extubation would worsen prolapse of membranes
- Long acting opiates (D/C same day)
- Avoid Paracervical block (bradycardia)
- Avoid pudendal block (spinal better)
- Cervical cerclage involves suturing the cervix close to treat cervical incompetence.
What are some pharmacological characteristics of drugs that involve placental transfer?
Drug characteristics that facilitate placental transfer include:
- small size (< 500 Dalton’s)
- nonionized/lipid soluble
- poorly protein bound
- high maternal concentration.
Drugs that undergo ion trapping (most importantly local anesthetics) can accumulate more quickly in the setting of fetal acidosis.
When would a paracervical block be indicated?
- What is the downside to a paracervical block?
When would a pudendal nerve block be indicated?
Paracervical Block Indications:
- Analgesia for the 1st stage of labor especially cervical dilation.
- Side effects: High rate of fetal bradycardia. The rate of fetal bradycardia is increased if fetal acidosis is present.
Pudendal Nerve Block Indications:
- Analgesia for the 2nd stage of labor.
- Mechanism: By blocking the pudendal nerve vaginal and perineal distention pain is blocked.
Fetal heart rate variability is primarily determined by what?
Parasympathetic tone of a fetus and is decreased during periods of CNS depression.
Why doesn’t Bupivicaine doesn’t readily cross the placenta?
Bupivacaine does not readily cross the placenta due to:
- its high protein binding
- high pKa of 8.1.
The latter results in a greater concentration of ionized drug which does not easily cross the placenta.
What is the benefits of elective caesarian section compared to vaginal deliveries
- Uterine Rupture 2. Hemorrhage
Discuss the cardiac output changes throughout pregnancy, delivery and post-partum?
Maternal cardiac output progressively increases during
pregnancy and throughout labor, reaching its peak
immediately following delivery (2.5x prepregnancy values or increase 150%).
Cardiac output then quickly declines postpartum and begins to approach prepregnant values by two weeks postpartum.
Stroke volume is the major change, not HR
How does renal physiology change in pregnancy?
How do the labs change?
What is the most common pre-renal and post-renal etiologies in pregnancy?
A serum creatinine concentration:
Greater than 0.8 mg/dL
Blood urea nitrogen concentration greater than 13 mg/dL (which are normal values for the nonpregnant patient) suggest renal insufficiency in the pregnant woman.
Creatinine clearance increases to 150-200 ml/min from 120 ml/min
Prerenal Etiologies:
- Hyperemesis Gravidarum
- Hemorrhage
Postrenal Etiologies:
- Nephrolithiasis
- Ureteral obstruction from gravid uterus
Which of the following changes occurring during pregnancy increases the risk for deep vein thrombosis?
Fibrinogen
A coded pregnant woman after 2 rounds of CPR does not have ROSC, what is your next step?
Delivery Caesarian section to get baby out
Cesarean delivery in the context of maternal cardiac arrest (peri-mortem cesarean delivery [PMCD]) should be strongly considered for every mother in whom return of spontaneous circulation has not been achieved after ~4 minutes of resuscitative efforts (Class IIa; Level of Evidence C).
Compressions done in supine position pushing uterus out of the way. (to the left)
What is the rate of CPR in a neonate?
Chest compressions should be performed in a 3:1 ratio with ventilation at a rate of 120 events per minute (i.e. 90 chest compressions and 30 breaths total per minute), and full chest recoil should be allowed after each compression.
This should continue until the neonate’s heart rate is > 60 bpm.
What is the dose of epinephrine you should use for a neonate in a code?
10-30 mcg/kg q3-5 minutes
Use 1:10,000 concentration of epinephrine
What is the recommended anesthetic for cervical dilation with bulging membranes that needs rescue cerclage placement?
Rescue = General
Prophylaxis = Neuraxial
Prophylactic cervical cerclage is usually performed under neuraxial anesthesia. When cervical dilation and bulging membranes are present, general anesthesia may be preferable if acceptable to the patient. In the absence of studies showing fetal outcomes, no technique is contraindicated, however, general anesthesia has the advantage of causing uterine relaxation which facilitates replacement of membranes.
What are some RF for breech presentation?
Mother:
Multiparty, multiple gestations, hydramnios, previous breech delivery, preterm gestation, oligohydramnios,
Baby: macrosomi, hydrocephalus, anencephaly,
Anatomy: pelvic tumors, uterine anomalies, pelvic contracture, cornual-fundal placenta, and placenta previa.
How do the labs in DIC in pregnancy appear?
Coags, FDP, D-Dimer, Fibrinogen, Anti-thrombin III?
Labs:
Increased PT
Increased aPTT
Increased fibrin degradation products
Increased D-Dimer
Decreased fibrinogen
Decreased antithrombin III
What is the RF for PDPH?
What are some S/S? (Classic one)
Treatment?
Signs/Symptoms
Fronto-occipital with radiation to the neck
CN symptoms
Worse with changes in position - Worse with upright; Relieved when lying flat
24-48 hours following dural puncture
Persists for months to years
Pathophysiology: Debated - Leakage of CSF initiates the syndrome
RF:
Young women (F>M), less likely in old
Thin women > Obese women
Pregnant > Not
Previous history of PDPH
Epidural needle > Spinal needle (Pencil point Whitacre needle; Sprotte also used)
Using air for Loss of resistance technique
Treatment = Blood Patch
What are the risk factors for uterine rupture?
Prior uterine surgery (upper segment scar >> lower segment scar)
Uterine hypercontractility
Oxytocin use
Prostaglandin use
Prolonged labor
Dystocia
Multiparity
Multiple gestations
Congenital uterine anomalies
Polyhydramnios
Trauma
What are the risk factors for pre-term labor?
Previous Preterm delivery
Non-Hispanic Black Race
Multiple gestations
Extremes of age
Low socioeconomic status
Low Prepregnancy BMI
Abnormal uterine anatomy
Abnormal cervical anatomy
Trauma
Abdominal surgery during pregnancy
Tobacco & Substance abuse
What is the most sensitive sign for uterine rupture?
Fetal Distress (Bradycardia, Decelerations)
What is the major disadvantage of paracervical nerve block?
Fetal Bradycardia and therefore:
- Fetal Oxygenation
- Fetal Acidosis
What is the APGAR scoring system?
0 1 2
Skin color
- Cyanotic
- Acrocyanotic (pink chest, cyanotic extremities)
- Pink
Heart rate
- Absent
- < 100 bpm
- >100
Reflex irritability
- NONE
- Grimace +/- feeble cry when stimulated
- ACTIVE
Muscle tone
- Absent
- Limp Some extremity flexion
- ACTIVE
Breathing
- Absent
- Weak, irregular, slow, shallow, or gasping
- Strong
What is the major mechanism of increase in maternal blood volume?
By what % does this increase?
An increase of up to 45% of maternal blood volume is seen during pregnancy.
This effect occurs early within pregnancy and is due to sodium retention via the renin-angiotensin system.
Which of the following is the optimum rostral level of sensory block when neuraxial anesthesia is used for a cesarean delivery?
Adequate neuraxial anesthesia for a cesarean section is best achieved through sensory blockade of the T4-S4 dermatomes.
What is the preferred refersal agent for reversal in a pregnant patient?
Why is this?
For this reason, a combination of neostigmine and atropine rather than neostigmine and glycopyrrolate may be considered for reversal of nondepolarizing neuromuscular blockers in pregnant patients to minimize the risk of fetal bradycardia.
What adrenergic drugs can be used to treat pre-term labor?
Terbutaline & Ritodrine
How does Alveolar Dead Space change during pregnancy?
Alveolar dead space is reduced during active labor secondary to a significant increase in cardiac output.
Alveolar dead space consists of alveolar units that are ventilated but not perfused; it is air that is inhaled but does not participate in gas exchange in the alveolar-capillary unit
Because cardiac output increases 10% to 40% during active labor, the parturient’s lung units are well perfused with resultant improvement in gas exchange at the level of the alveolar-capillary unit, reducing the functional alveolar dead space volume.
What are the two second line agents for uterine atony after oxytocin?
What are the doses?
What are the respective contraindications of each?
Methylergonovine (0.2 mg IM) “Methergine”
Contraindications:
- Hypertensive patient
- Coronary Artery Disease
- Pre-eclampsia / Eclampsia (These patients can stroke)
Carboprost Tromethamine aka 15-methyl prostaglandin F2 alpha aka “Hemabate”
(0.25 mg IM)
Contraindications:
- Pulmonary Hypertension
- Reactive airway disease (Asthma/COPD)
- Increased intrapulmonary shunt fraction
- Hypoxemia
What are the two mechanisms to achieve uterine relaxation when retained placenta/uterine inversion are present?
- Volatile Anesthetics
- Nitroglycerine (IV)
What are the physiological cardiovascular changes in pregnancy of:
Cardiac Output
Heart Rate
Stroke Volume
Intravascular Volume
Central Venous Pressure
Plasma Volume
Red Blood Cell Mass
Systemic Vascular Resistance
Cardiac Output Increased 40-50%
Heart Rate Increased 15-25%
Stroke Volume Increased 30%
Intravascular Volume Increased 35%
Central Venous Pressure No Change
Increased blood volume matched by increase in venous capacitance
Plasma Volume Increase 45%
Red Blood Cell Mass Increased 20%
Systemic Vascular Resistance Decreased 15-20%
What is the level of fibrinogen in pregnancy?
Fibrinogen levels will double
Pregnancy is a state of hypercoagulability with a most notable increase in the levels of fibrinogen, up to double the concentration, in order to limit postpartum hemorrhage.
What coagulation factors increase and what factors decrease in pregnancy?
Factors that increase include I (fibrinogen), VII, VIII, IX, X, XII, and von Willebrand factor which peak at the time of parturition.
Factors that decrease include XI, XIII, antithrombin III, and tPa.
Also, resistance to activated protein C occurs as well as a decline in the level of protein S.
High dose oxytocin has what effect on labs?
- Hyponatremia
This is due to ADH similarr=ities and natriuetic effects (Similarities between oxytocin and vasopressin)
What is the most common delay in latent phase of labor?
What is the latent phase time length for primigravida vs. multiparous women?
What is the rate of change of cervix per hour?
Unripe cervix
Primi = 20 hours with 1.2 cm/hour change
Multiparous = 14 hours with 1.5 cm/hour change
If no cervical change of two hours during active phase = Arrest of dilation
What is the complications associated with polyhydramnios?
What is the treatment for it?
Preterm Labor, PROM, and Postpartum Uterine Atony
Treatment = Indomethacin
What is the preferred agent for uterine relaxation?
- Nitroglycerine (200 - 400 mcg) chased with Phenylephrine
- Volatile Anesthetics
- Inhaled Amyl Nitrate
- IV Beta-Adrenergic Agonists (Terbutaline)
What are the risk factors for placenta accreta?
- Prior Uterine Surgery **Biggest Risk Factor** where now placenta overlies the uterine scar
- 1x C-section = 10-25%
- 2x C-section = >50% - Placenta Previa
- Multiparity
- Advanced Maternal Age
- Smoking
PUMAS Shoes (Previa, Uterine surgery and C-sections, Multiparity, Age, Smoking)
What is the differences between placenta accreta, increta and percreta, respectively?
- Placenta accreta occurs when the placenta implants with an absent decidua.
- It can result in life threatening bleeding when the placenta detaches following birth. - Placenta increta occurs when the placenta invades the myometrium
- Placenta percreta occurs when the placenta extends through the myometrium with possible adherence to other structures. Percreta is the most serious.
What is occuring during a variable deceleration vs. a late deceleration from a physiological standpoint?
Variable = fetal autonomic reflex response to transient mechanical compression of the umbilical cord.
- 1) Visually apparent abrupt decrease in FHR occurs
2) Abrupt FHR decrease is defined as from the onset of the deceleration to the beginning of the FHR nadir of less than 30 seconds
3) The decrease in FHR of 15 bpm or greater occurs, lasting 15 seconds or longer and less than 2 minutes in duration
4) When the variable decelerations are associated with uterine contractions, their onset, depth, and duration commonly vary with successive uterine contractions
Late Decelerations = Uteral Placental Insufficiency
What is the drug of choice for pruritis secondary to neuraxial morphine?
Nalbuphine:
Opioid-induced pruritus, treatment (off-label use): IV: 2.5 to 5 mg (Charuluxananan 1999; Cohen 1992; Jannuzzi 2016; Somrat 1999)
When given in small doses (3 mg) it does not reverse the analgesic effect of neuraxial morphine.
What is the rate of epidural/neuraxial failure rate for C-section?
What are the risk factors for failure?
3%
- Increasing maternal size, Late Labor Epidural Placement, and Rapid Decision to incision interval
How does magnesium infusions affect neurmuscular blocking drugs?
Magnesium reduces the release of acetylcholine from alpha motor neurons and decreases receptor sensitivity to acetylcholine.
Both decreased release of acetylcholine and decreased receptor sensitivity prolong the duration and efficacy of non-depolarizing neuromuscular blocking agents
What affect does volatile anesthetics and NO have on uterine muscle tone?
All volatile halogenated agents cause a dose-related relaxation of uterine smooth muscle.
Nitrous oxide has no effect on uterine muscle tone.
What is the mechanism of action of:
Metoclopramide?
Ranitidine?
Sodium Citrate?
Metoclopramide - antidopaminergic medication that enhances the response to acetylcholine of tissue in the upper gastrointestinal tract causing enhanced motility, accelerated gastric emptying, and increased resting lower esophageal sphincter tone in both nonpregnant and pregnant women.
increases LES tone and gastric emptying.
Onset = 1-3 minutes
Ranitidine competitive inhibitor of histamine at H2-receptors of the gastric parietal cells resulting in decreased gastric acid secretion, decreased gastric volume, and decreased hydrogen ion concentration.
Sodium citrate - nonparticulate antacid that acts as a buffering agent to neutralize gastric acidity
What is the most common cause of post-partum hemorrhage?
Uterine atony which results in continued bleeding from intrauterine vessels that are torn with placenta delivery.
What are the risk factors for uterine atony?
Risk factors for uterine atony include:
Multiparity, multiple gestations, Polyhydramnios, chorioamnionitis, proLonged labor, Oxytocin-induced labor, and mechanical factors.
CLOMP
What is vasa previa and what is the significance of that?
Vasa previa, not placenta previa, is a condition where vaginal blood loss represents fetal blood loss.
When rupture of membranes tears an abnormally inserted fetal vessel, the mother will remain asymptomatic and the blood loss will be small, but the fetus may exsanguinate quickly.
Fetus = 100cc/kg total blood volume so baby is usually only 350cc of blood total
What is the ABG that is seen in a pregnant patient?
pH, PaCO2, PaO2 and Bicarbonate?
Respiratory alkalosis (pH increases to 7.44) with a compensatory metabolic acidosis (pH may remain normal or be slightly elevated)
PaCO2 drops to 30
Arterial partial pressure of oxygen (PaO2) is increased in pregnancy (103-107 mm Hg) compared to normal nonpregnant levels (100 mm Hg).
HCO3 drops to 20
What is the number one cause of death related to pregnancy?
Cardiovascular diseases account for most pregnancy-related deaths in the United States.
When counted together with deaths attributable to cardiomyopathy, they represent over a quarter of pregnancy-related deaths in the U.S.
What are the severe features of pre-eclampsia?
- *Preeclampsia - Severe Features:**
- Severe hypertension (greater than or equal to 160/110 mm Hg)
- Thrombocytopenia (less than 100,000/microliter)
- Elevated liver enzymes
- Persistent right upper quadrant abdominal pain
- Persistent cerebral symptoms, including visual
- Renal insufficiency (serum creatinine twice normal
- Pulmonary edema
ACOG defines proteinuria as a urine dipstick value of:
- Greater than 1
- Protein-creatinine ratio of greater than or equal to 0.3
- 4-hour urine protein greater than 299 mg.
What agents are used to treat hypertension associated with pregnancy?
Treatment is recommended only for blood pressures greater than 160/105 mmHg that are persistent
- Labetolol: 20 > 40 > 60 > 80mg IV
Intermittent IV: Initial: 20 mg over 2 minutes; if blood pressure exceeds thresholds after 10 minutes, increase dose in increments of 20 to 40 mg every 10 minutes; maximum single dose: 80 mg. Note: If blood pressures remain above threshold after several intermittent doses, another agent should be used
- Hydralazine 5 - 15 mg IV
-
Nifedipine Initial: 10 mg once with fetal heart rate monitoring.
- If systolic or diastolic blood pressure remains above target at 20 minutes, give 10 or 20 mg orally depending on initial response.
- If blood pressure remains above target after 40 minutes, give another dose of 10 or 20 mg depending on previous response.
- If target blood pressure is not achieved after third dose, another class of agents should be considered (ACOG 202 2019; ACOG 767 2019; August 2019).
What are the advantages and disadvantages of a dilute epinephrine (1-5 mcg/mL) in Local Anesthetic and & Opioid Solution?
Advantages of including dilute epinephrine in local anesthetic/opioid solutions for epidural labor analgesia include more rapid onset and longer duration of analgesia, enhanced analgesia due to α-1 receptor stimulation (epidural vessel vasoconstriction), and decreased local anesthetic/opioid requirements.
Disadvantages include increased intensity of motor blockade, cost, and increased risk of drug error.
How would you determine if a patient with Von Willenbrand Disease is a candidate for neuraxial blockade?
1. Measure vWF levels, Factor 8 levels, and vWF ristocetin cofactor
What is the definition of fetal acidemia?
What are normal values?
Fetal acidemia is defined as pH < 7.21 or lactate > 4.8 mmol/L.
(Accessed through fetal scalp blood gas analysis)
Normal Values:
pH of >7.25
Lactate <4.2
What is the cellular signal transduction pathway responsible for Beta2 agonists (Terbutaline) affecting uterine muscle contraction?
The smooth muscle relaxation produces the desired effect of uterine relaxation.
The stimulation of adenylyl cyclase increases the conversion of ATP to cAMP. This decreases the available intracellular calcium and inhibits Myosin Light Chain Kinase resulting in impaired contractility.
How often can methergine be administered?
How often can carboprost be administered?
Methergine - 0.2 mg after delivery of anterior shoulder, after delivery of placenta, or during puerperium; may be repeated every 2 to 4 hours as needed.
Carboprost 0.25 mg - may repeat at 15- to 90-minute intervals; maximum total dose: 2 mg (8 doses)
If hemorrhage does not improve with Oxytocin, Methergine, Carboprost and fluids, what is the next drug and dose to be given?
What are the side effects of this drug?
Misoprostol
PR or Buccal Mucosa: 600-1000 mcg as a single dose administered immediately after delivery
Side Effects:
Increased Temperature >38
>10%: Gastrointestinal: Diarrhea, abdominal pain, N/V
1% to 10%:
Central nervous system: Headache
Gastrointestinal: Constipation, dyspepsia, flatulence, nausea, vomiting
How do tocolytic medications affect Uterine Blood Flow?
Uterine blood flow is decreased by systemic hypotension, uterine vasoconstriction, and uterine contractions (particularly when pharmacologically augmented).
Tocolytic agents such as β2 agonists improve uterine blood flow by reducing UVR (due to uterine relaxation)
What is Uterine Blood Flow proportional to?
- Directly proportional to Uterine Arterial Pressure
- Inversely proportional to uterine venous pressure and uterine vascular resistance
What is the potential problem with administering NSAIDs to a mother for tocolysis?
Maternal administration of NSAIDs for tocolysis may result in premature closure of the ductus arteriosus.
What is a potential neonatal complication of administration of ritodrine?
Fetal hypoglycemia may occur as a result of the maternal administration of ritodrine.
Physiology: The elevated glucose crosses the placenta and causes fetal hyperglycemia initially. Fetal hyperglycemia stimulates the fetal pancreas to secrete more insulin as a method to balance the glucose load. However, if the fetus is separated from the mother at this time the glucose supply is removed. As a result the neonate is hyperinsulinemic without a strong glucose supply, and therefore becomes hypoglycemic. Hyperinsulinemia, in the neonate, causes hypoglycemia as glucose is taken up in organ and muscle.
What is the pathophysiology of Preeclampsia in terms of:
Vascular changes?
Volume Status?
SVR?
Uterine Tone?
Blood flow to placenta, uterus, and kidenys?
Platelet levels?
TXA2 levels, PGI2 levels, Nitric oxide levels
Pulmonary status?
Coag levels (PTT)
Preeclampsia is characterized by global vascular hyperreactivity leading to intravascular volume depletion, high systemic vascular resistance, uterine vasoconstriction within the myometrium, and decreased uterine and placental blood flow.
There is an elevation of thromboxane A2 levels and a decrease of prostacyclin PGI2 levels leading to a primarily vasoconstricted state. Endothelial cell activation leads to reduced nitric oxide production and platelet activation.
Renal blood flow is decreased leading to decreased urine output.
Pulmonary edema occurs secondary to capillary leakage and increased inflammatory response.
The hypercoagulable state and platelet activation is juxtaposed with a coagulopathy secondary to decreased platelet counts and prolonged PTT.
What are the risks of surgery during pregnancy in terms of neonate outcomes?
Surgery during pregnancy should occur only after careful consideration, as there are risks to both the mother and the fetus including:
Miscarriage
Preterm labor
Low birth weight
Aspiration
What ventilator changes do you want ensure NOT TO DO during non-Obstetric surgery in a pregnant patient?
It is also prudent to avoid hyperventilation as decreased PaCO2 can cause uterine vasoconstriction.
Maintenance of maternal PaO2 is also prudent to ensure adequate delivery to the fetus.
What are the risk factors for placental abruption?
Risk factors include:
Maternal hypertension
Maternal cocaine and/or tobacco abuse
Trauma
Advanced maternal age
Advanced Parity
(PATCH)
If you have surgery that can be delayed in non-obstetric surgery in a pregnant patient, when should you delay until?
2nd trimester if cannot delay until delivery.
Physiologically, what is eclampsia the result of?
Eclampsia is a result of cerebral edema and related to hypertensive encephalopathy* or *posterior reversible encephalopathy syndrome (PRES)
Why is Corticosteroids (Betamethaone / Dexamethasone) given to preterm mothers?
Why is Magnesium given?
Pre-delivery corticosteroid use has been associated with:
- Reduction in respiratory distress syndrome
- Reduction in ntraventricular hemorrhage
- Reduction in neonatal death.
Magnesium = Fetal Neuroprotection
How is primary pulmonary hypertension diagnosed?
How would you approach a patient with neuraxial anesthesia?
What is mortality in these women?
Pulmonary hypertension is defined as mean pulmonary artery pressure over 25 mm Hg at rest or 30 mm Hg with exercise
Neuraxial analgesia is useful for preventing pain-induced increases in pulmonary vascular resistance. Dilute local anesthetic solutions with the addition of opioids will minimize the decrease in systemic vascular resistance (SVR).
Mortality is 30-55%
