ITE OB 3 Flashcards
Why do pts shiver during labor after an epidural?
redistribution of core heat to periphery
- blunting of Autonomic thermoregulatory function
but shivering will occur irrespective of whether neuraxial anesthesia is used or not
the P50 of adult hgb is ___mmHg, and the P50 of fetal hgb is ___ mmHg which is Left shifted, greater affinity for O2
26 mmHg
19 mmHg
Early _______in pregnancy (before 15 weeks) compared to late pregnancy has higher risk of pregnancy loss, rupture of membranes, club foot.
amniocentesis
In the first stage of labor, maternal oxygen consumption increases by __%, and in the second stage of labor, by __%. This is driven by hyperventilation, pushing of infant, uterine contractility.
40,
75%
arterial partial pressure of oxygen (PaO2) is increased in pregnancy to ___ mmHg, compared to normal nonpregnant levels at __ mmHg, starting in the first trimester of pregnancy
105 mmHg
100mmHg
Pregnancy leads to a respiratory (acidosis/alkalosis) with compensatory metabolic (acidosis/alkalosis) . On ABG, this is represented as:
respiratory alkalosis
metabolic acidosis
pH slightly increased
decreased PaCO2, serum HCO3, base excess
1st and 2nd most common cause of pregnancy related deaths in US
CV conditions
Infection
Biophysical profile (BPP) includes: (5)
- Non stress test
- fetal breathing
- fetal movement
- fetal tone
- amniotic fluid vol
Biophysical profile (BPP) is performed starting at ___ weeks
32-34
BPP is considered reactive when _ fetal heart rate accelerations of __ beats/min for __ seconds, within a 40 min time period.
2 FHR accelerations
15 beats/min
15 seconds
Pregnant women with a cord injury above __ spinal level will have an increased risk of preterm labor.
T11
_____ anesthesia can be safely performed in pregnant pts with severe valvular disorders
epidural
- safely titrated
In pts with severe mitral stenosis, which peripartum period is the most tenuous?
the period directly after delivery
- autotransfusion: blood in uterus is being placed back into maternal circulation
Fetal oxygen saturation via fetal pulse oximetry is typically between __% and __%, and (has/has not) been able to predict fetal acidosis.
35-65%
has NOT
There is a 5x increase incidence of pulmonary thromboembolism, which is multifactorial, but mainly d/t _______
caval compression by the gravid uterus
- leading to increased venous stasis -> DVT and PE
Amniotic fluid embolisms (inflammatory process) usually present ___ (time) after vaginal delivery
8 minutes
Fetal weight above ____ grams is an independent predictor of unsuccessful TOLAC
4000 g
_____, a synthetic prostaglandin E1, unlike carboprost, does NOT carry the risk of bronchoconstriction
Misoprostal
Asthma is an (relative/absolute) contraindication to carboprost, a synthetic prostaglandin F2-alpha
relative
- controlled asthmatics w/ no recent exacerbations can receive it safely
If left untreated, umbilical cord prolapse can lead to ___ and ____. It is an indication for emergent C/S.
umbilical cord compression and fetal asphyxia
Risk factors of umbilical cord prolapse (4)
- low birth weight
- multiparity
- multiple gestations
- artificial ROM
Amniotic fluid embolism is also referred to as _____
anaphylactoid syndrome of pregnancy
- amniotic fluid in systemic circulation results in massive inflammatory release and DIC
Clotting is broken up into two phases ____ and ___. Platelets are important for both.
Primary and secondary hemostasis
Primary hemostasis is the formation of ____
initial platelet plug
- Unstable
Secondary hemostasis is the formation of the ____
fibrin clot
- stable
Alveolar dead space is reduced during ACTIVE labor secondary to ____
significant increase in Cardiac output (40%)
- lungs are well perfused, (and ventilated)
Alveolar dead space consists of alveolar units that are _______
ventilated but not perfused
- air is inhaled, but does not participate in gas exchange
If a pt is at high risk of previous alloimmunization and potential antibody presence, should a type and cross be obtained?
- Emergent sx?
- Nonemergent sx?
emergent - type + screen sufficient
Nonemergent - type + cross
umbilical (artery/vein) is more representative of acid base status of the fetus. Usually have a pCO2 of __ and a PO2 of ___
artery
pCO2: 50
PO2: 20
umbilical (artery/vein) is more representative of acid base status of placental function. Usually have a pCO2 of __ and a PO2 of ___
vein
pCO2: 40
PO2: 30
The effects of adrenergic agents in pregnancy (ie. phenylephrine) are (increased/decreased) in pregnancy
decreased (blunted)
Maternal cardiac output returns to normal after ____ (time)
2 weeks
Lambert-Eaton syndrome involves _____, which is similar to magnesium toxicity (inhibits calcium ion influx).
autoantibodies targeting presynaptic calcium channels to inhibit calcium ion influx, and thus prevents ACh release
Pre-eclamptic pt in labor gets _____ IV for seizure prophylaxis. If they get toxic levels, they have (hyper/hypo)reflexia, and (tachycardia/bradycardia)
Magnesium.
hyporeflexia
bradycardia
Myasthenia gravis involves autoantibodies to _____
post-synaptic ACH receptors at the NMJ
Pregnancy is a hypercoagulable state d/t increases in mainly ____ and ____
factor VII and fibrinogen
Subarachnoid hemorrhage during pregnancy should be treated _____
the same as nonpregnant females. (mortality 40%)
- only after treatment, should you they continue until term gestation
____ repair is seen in pts with vascular defects (pulmonic/tricuspid atresia or ventricular defects such as single ventricle)
Fontan repair
_____ repair is associated with the highest prevalence of arrhythmias during pregnancy
Fontan repair
Why is neuraxial anesthesia with meticulous attention to preload the preferred method for C/S in pts with valvular abnormalities compared to GA?
Avoids adverse effects of myocardial depressant medications and positive pressure ventilation
____ is the largest risk factor when considering the passage of meconium, leading to possible aspiration. This can be prevented by ______
Gestational age,
using the earliest gestational age
When measuring umbilical cord blood sample, it is important to recall that umbilical arteries are carrying blood (towards/away) from the fetus and that a normal sample will appear _____.
Away, venous
Umbilical venous blood gas will appear _____, since it is carrying maternal arterial blood (towards/away) from fetus
Arterial, towards
Uterine blood flow is determined by _______. With ______ being the single most important factor in determination of blood flow.
BP divided by uterine vascular resistance
Hyperventilation of mom will result on hypocarbia, which results in a (right/left) shift and reduce oxygen delivery to fetus
left shift
Aortocaval compression by gravid uterus can decrease cardiac output by _%.
25%
Ephedrine, an indirect sympathomimetic, is generally avoided In pregnant pts as it can increase risk of _____
Fetal acidosis
Nitrous oxide is usually avoided in obstetric pts d/t inhibition of _____
Methionine synthase,
- involved in folate metabolism and DNA synthesis.
- inhibition can lead to miscarriage
The 1st and 2nd most common cause of non-obstetric surgery is _____ and _____
- Cholestasis,
2. appendicitis
Primary pulmonary Hypertension in pregnancy is ____.
Very very bad. High maternal mortality. Pregnancy is discouraged, termination is advised.
Nitrous oxide in pts with pulmonary HTN is _____
Avoided, as it can increase pulmonary vascular resistance, leading to RHF
Anesthetic requirements (MAC) are decreased by up to __% in pregnancy
40%
Acute CP distress following the evacuation of a molar pregnancy has been attributed to _______ in more than half of cases.
This presents as CP, cough, tachycardia, hypoxemia, diffuse rales, b/l pulmonary infiltrates.
Trophoblastic embolization (trophoblastic cells entering venous outflow from uterus during evacuation)
