Obstetric Anesthesia: Hertz cont. Flashcards
How is chronic HTN defined?
What drug is safe for mom to treat it?
BP > 140/90 before 20 weeks gestation
Labetolol (mixed alpha, beta blocker)
What is the triad of symptoms of preeclampsia?
HTN >140/90 or > 20% of baseline
Proteinuria > 300mg /24 hrs AND/OR
Edema (hand, face)
What are the risk factors of preeclampsia? (5)
Primarily primigravidas
Primipaternity
Previous Hx
Obesity
Multiple gestations
What is the etiology of preeclampsia? (4)
- Not definitely known
- Abnormal fetal trophoblastic cell migration through placenta resulting in increased BP
- Changes in placental/abnormal vascular endothelium
- Platelet adhesion occurs resulting in release of seratonin, thromboxane
What vasoconstrictors are more prevalent in preeclampsia? (4)
- Thromboxane (AT1, AT2 platelet aggregation)
- Endothelin (causes pulmonary HTN)
- Angiotensin II
- Serotonin
How is severe preeclampsia defined?
One of the following:
- BP > 160/110
- Proteinuria > 5 Grams/24 hrs
- Symptoms such as headache, blurred vision, oliguria, pulmonary edema, myocardial dysfunction, RUQ pain (liver congestion), platelets < 100k, HELLP
Severe preeclampsia contributes to ___ - ___% of maternal deaths and ____% perinatal deaths.
20-40
20
What turns preeclampsia into severe eclampsia?
HELLP
What is contraindicated in HELLP syndrome?
REGIONAL
Can seizures occur with preeclampsia?
Yes
What is the treatment of preeclampsia?(5)
- Bedrest
- Sedation
- Labetalol, Hydralazine
- Magnesium sulfate
- Delivery
What are antihypertensives safe for mom? (5)
- Labetolol 5-10 mg IV
- Hydralazine 5mg IV
- Methyldopa 250-500 mg PO (alpha 2 agonist)
- Magnesium sulfate
- Nitroprusside (arterioles, venules)
What are attributes of magnesium sulfate? (3)
Treats hyperreflexia and prevents seizures
Direct vasodilating action on smooth muscle of arterioles and uterus
Potentiates sedation
Excessive magnesium sulfate can cause what? (6)
- prolonged PR interval, widened QRS (5-10 mEq)
- muscle weakness (10 mEq)
- loss of DTRs
- respiratory depression
- SA, AV block (15 mEq)
- cardiac arrest (25 mEq)
SNP in doses > _____mcg/kg/min or prolonged period can increase risk of what?
10 mcg/kg/min
cyanide toxicity
What drugs do you NOT use in pregnant women?
ESMOLOL –adverse fetal effects
Calcium channel blockers–tocolytic action and potentiate circulatory depression induced by magnesium
What is the anesthetic management of severe preeclampsia?
Pts are critically ill and need to be stabilized prior to any type of anesthesia.
Need a-line
What are antihypertensives needed in OR?
Labetalol
Hydrazaline
NTG
Nitroprusside
What are signs of magnesium toxicity? (3)
Oversedation
Loss of reflexes
DROPPING SATURATIONS
How do we manage a preeclamptic patient? (3)
Monitor UO
Hypovolemia treated with no more than 500ml LR
Check platelets and coags prior to regional anesthesia
Avoid regional if platelets < _____, but lowest is _____.
100k
70k
What is ideal anethesia for preeclamptic pt?
Epidural or spinal
Vaginal
C/s
What is controversial regarding regional in the preeclamptic pt?
EPI contained in test dose
What drugs/doses are appropriate for hypotension in pregnant patients, specifically preeclamptic pts that become hypotensive during epidural placement?
Ephedrine 5mg
Phenylephrine 50 mcg
Note: Pregnant women are more sensitive to meds.
What are anesthetic considerations for general anesthesia in preeclamptic pts? (4)
- Difficult airways so be prepared!
- Limit IV fluid to avoid pulmonary edema
- Doses of non-depolarizing relaxants are reduced in patients on magnesium since it potentiates NMB.
- A-line for severe preeclampsia
What is usually better tolerated, regurgitant or stenotic lesions in the pregnant woman?
regurgitant
What is the 2nd most common valve defect in pregnant pts?
mitral regurge
What should you avoid in mitral regurge? (3)
Increases in SVR
Decreases inHR and contractility
Maintain sinus rhythm
What should you avoid in aortic regurge? (2)
Increases in SVR
Decreases in HR and contractility
Note: consider afterload reduction
What should be avoided in mitral stenosis? (3)
Avoid tachycardia
Atrial fibrillation–perfusion depends on atrial kick
Increases in blood volume because may precipitate pulmonary edema
Note: Maintain SVR
What should you avoid in aortic stenosis? (3)
Decreases in SVR
Avoid bradycardia
Avoid hypovolemia
What is the dose of mg sulfate?
Loading dose: 4 GRAMS then 1-3 gram/hr
Plasma level: 1.5 -2 mEq/L
Therapeutic level: 4-6 mEq/L
What are congenital heart diseases? (3)
left to right shunt
right to left shunt
cardiomyopathy
What are left to right shunts? (3)
ASD–atrial septal defect
VSD–ventricular septal defect
PDA–patent ductus arteriosus
What should you avoid in left to right shunt? (3)
Avoid excess fluids
Avoid trendelenberg position
Avoid increases in SVR
What is tetrology of fallot?
RV hypertrophy
Pulmonary valve stenosis
Ventricular septal defect
Overriding aorta
What should you avoid in right to left shunt (ie. tetralogy of fallot for example)? (3)
Decrease in SVR b/c enhances shunt leading to cyanosis. Use phenylephrine
Decrease in blood volume because preload is necessary to eject blood past the outflow obstruction
Avoid myocardial depressants to avoid decrease to pulmonary circulation
Cardiomyopathy can present at any point of pregnancy. True or false?
True
What are risk factors for cardiomyopathy? (5)
- multiple gestation
- preeclampsia
- obesity
- advanced age
- breastfeeding
What are anesthetic considerations for cardiomyopathy? (4)
Invasive monitoring
Intubation, ventilation
inotropic support
IABP
What are risk factors for gestational diabetes? (4)
- Advanced age
- Obesity
- Family hx of diabetes
- Hx of stillbirth, neonate death, etc.
What effects does gestational diabetes have on mom? (4)
HTN
Polyhydramnios
C-section more likely
Preterm labor more likely
What are the effects of gestational diabetes on baby? (5)
Macrosomia (large baby)
Structural malformations
Intrauterine death
Respiratory distress syndrome
Neonatal HYPOglycemia
What are structual malformations that can occur in baby with diabetic mom? (6)
- CNS: anencephaly (brainless), spina bifida, encephalocele
- Transposition of great vessels, situs inversus, single ventricle
- Caudal regression–dolphin like features
- Renal agenesis
- Anal/rectal atresia–hole not present
- Lack of pulmonary development
Critical organogenesis before ____th week.
7th
What are anesthetic considerations for gestational diabetic pts? (3)
Autonomic dysfunction leads to increased risk of hypotension
Gastroparesis–give reglan
Strict sugar control
How may asthma change during pregnancy?
May improve, worsen, or stay the same
How will ABG change for pregnant women?
pH increases
CO2 decreases
pO2 decreases
What are anesthetic concerns for pregant asthmatic? (3)
- Prevent hypocarbia
- Prevent hypercarbia –> vasoconstriction–>decreased UBF–> fetal distress
- Avoid high thoracic block
What type of anesthesia is preferred for asthmatic?
Regional, spinal or epidural
What meds do you avoid in asthmatics? (3)
Hemabate–prostaglandin F2alpha increases smooth muscle tone–>constricts a/w
**Methergine **
Labetolol–use hydrazaline, snp
What is BMI for obesity?
30 kg/m2
What are obese pts at increased risk of? (4)
- HTN
- Aspiration
- Diabetes
- Increased risk of DVTs
What is a risk factor for c/s for obese pt? (4)
Increased risk of fetal distress
Increased risk for abnormal labor (arrest of descent)
Increased risk of shoulder distocia
Increased risk of maternal death
Do people recover from cardiomyopathy?
What do you do if it occurs antepartum?
50% do not fully recover and some require transplant
Promptly deliver the baby
