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144 Cards in this Set
- Front
- Back
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Oxygen consumption increases by _____% during pregnancy due to the metabolic needs of the fetus, uterus, placenta and secondary to cardiac and respiratory work
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O2 consumption increases 30-40%
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How much does the toracic cage circumference increase during pregnancy?
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5-7 cm
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Epistaxis and bleeding during DL may occur because of ________ and ______ of the upper airway
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Venous engorgement and edema of upper airway
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What are the leading causes of anesthesia related maternal morbidity and mortality during pregnancy?
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Failure to intubate or ventilate and aspiration
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Airway conductance ______ during pregnancy
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increases
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How much does TV increase during pregnancy?
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45%
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When does FRC decrease during pregnancy?
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After the 5th month, decreased expiratory reserve leads to rapid and pronounced desaturation
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How much does minute ventilation change during pregnancy?
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Minute ventilation increases 45% d/t increased TV
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What happens to respiratory rate during pregnancy?
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Remains unchanged or decreases up to 15%
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What is the average PaCO2 of a pregnant woman? When does this occur?
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PaCO2 decreases to 30 mmHg by 12th week
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What happens to PaO2 during pregnancy? When is PaO2 highest?
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PaO2 increases; highest in 1st trimester
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What happens to PaO2 in the supine position?
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PaO2 falls below 100 in supine position
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What happens to HCO3 during pregnancy? Why?
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Decreases to compensate for respiratory alkalosis
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What 5 cardiac measures increase during pregnancy?
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CO, SV, HR, LVEDV, EF all increase
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Where is blood shunted to during pregnancy?
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Kidneys, uterus, breasts, and skin
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What 2 cardiac measures/values decrease during pregnancy?
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SVR and MAP decrease
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How much does uterine blood flow change during pregnancy?
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Increases from 50ml/minute to 700 ml/minute
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How much does O2 consumption change during pregnancy?
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Increases 20%
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What happens to arterial pH during pregnancy?
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Does not change; respiratory alkalosis (paCO2 30-32) offset by decreased bicarb (16-21 meq/L vs. 24 nonpregnant)
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When do hemodynamic changes start to occur
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by 8-10 weeks
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How much has maternal CO increased by 32 weeks gestation? Immediately postpartum?
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32 weeks- has increased 30-50%; immediately postpartum has increased 75-80%
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How much does stroke volume change during pregnancy? HR? MAP? Blood volume?
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SV: increases 30%
HR: Increases 15% MAP: decreases 10-15% Blood Volume: increases 35-45% |
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Cardiac output is highest:
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just after delivery (75% above predelivery values for the first hour post-delivery) and remains elevated above predelivery values for first 48 hours
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Venous return _____ during pregnancy
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Increases
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Total peripheral resistance ______ by _____% during pregnancy
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Total peripheral resistance decreases by 15%
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What are some expected cardiac auscultation findings during pregnacy?
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Accentuated and split S1, normal S2, Systolic ejection murmur (present in 90%); diastolic flow murmur (in 20%), S3 heart sound (in 80%), occasional S4
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Plasma volume _____ by _____% during pregnancy, while RBC volume ______ by _____%
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Plasma volume increases 55% and RBC volume increases by 30%
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Total blood volume increases _____ during pregnancy. Plasma volume increases _______ than RBC volume leading to ________.
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Blood volume increases 45%; plasma volume increases more than RBC volume, leading to a dilutional/relative anemia
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Platelet count is ____ during pregnancy
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Stable- plateley consumption and production both increase
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Plasma proteins are _____ during pregnancy
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Diluted
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Plasma cholinesterase _____ during pregnancy and does not return to normal until ______ weeks postpartum
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plasma cholinesterase decreases and does not return to baseline until 6 weeks postpartum
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What is the anesthetic implication of decreased plasma cholinesterase during pregnancy ?
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Low to low-normal dose of succinylcholine; will have prolonged duration of action from sux
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Albumin ____ during pregnancy, causing decreased plasma _______
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albumin decreases, causing decreased plasma oncotic pressure- leading to edema
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Pregnant patients are ____coagulable
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hypercoagulable
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All clotting factors increase during pregnancy except _____ and _____.
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XI and XIII
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The supine position causes _____ occlusion during pregnancy (starting at ____ weeks)
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IVC occlusion starting at 13-16 weeks, evident by 20 weeks
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What percent of preganant women suffer from supine hypotension syndrome during pregnancy?
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5% have parasympathetic response; remaining 95% respond to IVC occlusion and resulting decreased cardiac output by increasing vascular resistance to normalize BP
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Compression of IVC in supine position is decreased once______
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baby's head is engaged in pelvis
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A patient suffering from supine hypotensive syndrome will experience
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decreased BP, tachycardia, pallor, faintness
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What are the diagnostic criteria for supine hypotensive syndrome? What is the treatment?
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MAP decreases by more than 15 mm Hg and HR increases by 20 bpm (sustained); treatment is left uterine displacement position
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What should pregnant women receive prior to surgery?
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30 ml Bicitra 30-45 minutes prior to surgery
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Severity of aspiration is influenced by the increased _____ and decreased ______.
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Increased volume and decreased pH
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OB patients at high risk for aspiration should receive _____ in addition to bicitra 30-90 minutes before surgery
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Reglan
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Pregnant patients should only be extubated when _____
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fully awake
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All pregnant patients are considered full stomach and require:
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RSI with cricoid pressure, avoid PPV if possible
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Liver enzymes (except alk phos) are _____
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upper normal values
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the gall blader emptying is ____ during pregnancy, leading to
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slow gall bladder emptying leading to residual bile volumes and gall stones
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GFR ______ by ____% during pregnancy
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GFR increases 50% during pregnancy
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Creatinine and BUN _____ during pregnancy
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decrease
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Kidneys _____ during pregnancy and ureters and renal pelvis ______
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Kidneys enlarge during pregnancy and ureters and renal pelvis dilate
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Glucose excretion by the kidneys is ______ during pregnancy
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elevated glucose excretion
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During pregnancy, insulin secretion _____ and tissue sensitivity ______
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insulin secretion increases and tissue sensitivity decreases
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Diabetogenic state of pregnancy is mediated by what hormone? How long does this state persist?
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human placental lactogen (HPL); returns to normal within 24 hours post delivery
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Does insulin cross the placenta?
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No
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Hyperglycemia in the mother leads to ______ in the fetus after delivery
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rebound fetal hyperglycemia
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Total T3 and T4 values increase by ____% during pregnancy, and free T3, T4 values ______
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total T3, t4 increase by 50% but free T3 T4 remain unchanged
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The thyroid gland _____ in size during pregnancy
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size increased, but euthyroid state maintained
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Pregnant patients have a _____ sensitivity to local anesthetics
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Increased sensitivity
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Pregnant patients have an increased dependence on the ______ nervous system
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Sympathetic
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The epidural space is decreased during pregnancy dye to _______
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epidural venous engorgement
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Increased abdominal pressure during pregnancy enhances _____ spread of local anesthetics
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Transdural
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Pregnant patients have exaggerated lumbar _____, allowing increased cephalad spread of local anesthetics
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Lumbar lordosis
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Pregnancy induced analgesia is mediated by
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increased endorphins and enkephalins in the CSF and brain; peaks at term and can be reversed with intrathecal narcan
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Increased reliance on sympathetic tone primarily effects
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venous capacitance to counteract the adverse effects of uterine compression; peaks at term and returns to normal 36-48 hours postpartum
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Extradural pressures are _____ during pregnancy
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higher
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CSF volume is _____ during pregnancy
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decreased
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How is blood flow to the uterus supplied?
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Internal iliac flows to the uterine aftery; uterine and ovarian arteries supply placenta and 90% of flow "spurts" into the intervillous spaces
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Uterine blood flow at term comprises about _____% of cardiac output
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12%
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Is uterine blood flow auto-regulated?
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No
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What is the equation for uterine blood flow?
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(Uterine Arterial pressure- uterine venous pressure)/(uterine vascular resistance)
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What factors will decrease uterine blood flow?
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Hypotension (supine position, hypovolemia, post- sympathetic blockade); incresed venous pressure (contractions, hypertonic uterus (pitocin), seizures, etc), increased uterine vascular resistance (catecholamins, vasopressors (phenylephrine >ephedrine)
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pregnant patients have _____ sensitivity to vasoactive agents
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Decreased sensitivity
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Alpha agonist drugs cause decreases in ______
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Myometrial and placental blood flow
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ACE inhibitors may cause _____ in pregnant patients
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decrease uterine blood flow by dilating peripheral vascular beds and stealing flow away from uterus
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Prostaglandin inhibitors _____ uterine blood flow
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decrease
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increased cAMP and cGMP cause uterine vessels to _____
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dilate
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_____ umbilical arteries take blood from the _____ to the ______
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2 umbilical arteries carry deoxygenated blood from the fetus to the placenta
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Oxygenated blood is carried from the placenta to the fetus by way of _____ umbilical ______
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1 umbilical vein
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Can most drugs cross the placenta? What factors influence their ability to cross?
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Most drugs can cross the placenta; amount of transfer is based on molecular weight, lipid solubility, ionization, concentration gradient, protein binding, metabolism in the placenta (p450 enzymes), intervillous blood flow, thickness of the membranesm and ratio of maternal to fetal blood flow in a given area
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Who's law describes the ability of drugs to cross the placenta?
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Fick's Law of diffusion
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Do not allow the mother's BP to fall below _____ of baseline values d/t risk of decreased blood flow to the fetus
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20%
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Fibrinogen _____ during pregnancy
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Increases
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WBC counts ______ during pregnancy to about ______
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increase to 13,000
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What is the average blood loss for a vaginal and CS delivery?
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600 ml vaginal delivery, 1000 ml CS
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LES tone _____ during pregnancy due to what hormone?
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LES tone decreases due to increase progesterone and decreased motilin
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Gastric emptying ____ during pregnancy d/t what hormone
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Decreases d/t progesterone
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Decreased plasma protein means that ________ drugs will have more free drug available
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highly protein bound drugs will have increased availability of free drug
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Pregnant patients have _____ sensitivity to aminosteroid drugs
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incrased sensitivity
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MAC is _____ in pregnant patients, and rate of induction is ______.
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MAC decreased, rate of induction is increased
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______ tone predominates in the first trimester
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PNS/Vagal
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Fetal heart tones can be heard with a doppler at _____ weeks and a fetoscope at _____ weeks.
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10-12 weeks with doppler, 17-20 weeks with fetoscope
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Fetal movement is felt at _____ weeks
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20
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Mean pO2 of fetal blood is
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30 mm Hg
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Fetal Hgb has ______ for O2
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higher affinity
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Normal FHR is _____
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120-160 bpm
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the baby's stations is describes where the ____ lies in relation to the ______
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presenting part in relation to the ischial spines
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The latent phase of Stage I has pain in what dermatomes? What type of block is good for this?
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Visceral fibers at T11-T12 stimulated when contractions generate at least 25 mm Hg force; paracervical block works well for this
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The active stage of labor generally starts at _____ cm dilation and pain is transmitted via what nerve roots?
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4-5 cm dilation; pain from T10-L1
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The late active phase starts at ______ cm dilation; _____ pain begins from the stretching of vagina,perineum, and pelvic floor. What block works well for this?
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starts at 7-8 cm; somatic pain begins; pudendal block works well
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Pain coverage for the late active stage of labor requires coverage from _____ to _____.
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S2-S4 sensory block
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Describe the level of block needed for each stage of labor
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Latent: T11-T12 sensory block
Active: T10-L2 sensory block Late Active: S2-S4 sensory block Stage 2: delivery- redose epidural Stage 3: T10-S4 |
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What clotting factors increase during labor?
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I, II, VII, X
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Early decelerations are often caused by ______, and are a _____ finding
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Head compression; normal finding
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Variable decelerations are related to_______; they can often be treated with _______
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Cord compression; can be treated by changing position
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Late decelerations ______ a contraction and can be caused by _______
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Late decelerations follow contractions; indicate utero-placental deficiency- ABRUPTION
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A sinusoidal pattern on a fetal heart rate tracing indicates
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Severe acidosis and fetal distress- terminal rhythm
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______ fetal positioning causes back labor and more severe pain
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ROP
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What is the IV tocolytic of choice
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MgSO4
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How does Mg work?
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Inhibits Ach at the neuromuscular junction and decreases the sensitivity of the motor end plate for Ach
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Patients receiving Mg infusions are prone to _____ during regional anesthesia
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Hypotension
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MgSO4 _____ muscle relaxants
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Potentiates
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How do Calcium channel blockers work as a tocolytic?
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Inhibits transmembrane calcium thereby reducing myometrial contractility
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You attend a delivery of a pre-term infant whose mother had been receiving tocolytic therapy to prevent delivery. What do you expect?
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Uterine hypotonia and increased bloeding
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What level of block do you need for a tubal ligation? for a hysterectomy/D&C?
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T6 for tubal; T10 for D&C/hysterectomy (or higher if abdominal)
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The period of highest concern for teratogenicity begins at _____, peaks at ______ and gradually decreases and becomes minimal through day ______.
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Begins at 15-18 days post-conception, peaks at 30 days, and gradually decreases and becomes minimal until days 55-90
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N20 is contraindicated during pregnancy d/t concern about
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Methionine synthetase and tretrahydrofolate inhibition causeing concern for DNA production and demyelination
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What 3 maternal factors must be avoided at all costs to preserve adequate fetal hemodynamics?
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Maternal hypoxia, maternal hypotension, and maternal hypercarbia
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Benzodiazepines and N20 are pregnancy risk category ____ and should only be given _____
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Cat. D; only give if life-threatening treatment needed (seizures)
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NMB should be antagoinized with which anticholinergic during pregnancy?
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Atropine- robinul does not cross the placenta
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Local anesthetics disrupt transmission through what fibers before other fibers?
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C and Agamma (basis of differential block)
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ATPTPMVP
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Autonomics, temperature, pain, touch, pressure, motor, vibration, proprioception
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Epidural level is determined by _____ and _______
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drug volume and position
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Epidural effect (density) is determined by ______
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Concentration of drug
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A positive intravascular test dose is evidenced by:
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Epi CV effect- HR increase >10bpm and T-wave flattening of 25%
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Fetal bradycardia is more likely with which type of regional anesthetic?
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SAB
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Autonomic blockade d/t regional anesthesia may result in uterine hyperstimulation because:
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Removal of catecholamines leaves oxytocin unopposed (if conservative treatment is ineffective, terb or NTG may be helpful)
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PDPH is likely to be caused by puncture of the dura by a ______ needle
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Quinke needle (cutting needles)
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If a patient is receiving LMWH, you should wait at least ______ hours before performing a block d/t risk of _______
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wait 10-12 hours d/t risk of epidural hematoma formation; after block. wait at least 2 hours for re-do and remove epidural catheter prior to first post-op dose
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Baby should ideally be delivered within ____ minutes of uterine incision
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2 minutes
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______ is a useful induction drug in the hypovolemic pregnant patient
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Ketamine
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The two best choices to treat maternal hypertension are
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Labetalol and hydralazine
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What anti-hypertensives should be avoided in the pregnant patient?
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Sodium Nitroprusside (crosses placenta- fetal hypotension); ACE-inhibitors may contrinute to "uterine steal" and may affect fetal renal function
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What is the best treatment for hypotension in the pregnant patient?
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Ephedrine (>neo)
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What is the anti-coagulant of choice in the pregnant patient?
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Heparin
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Oxytocin causes uterine ______ and vascular _______
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uterine smooth muscle constriction and vascular dilation
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What is the indication and mechanism of Methergine use? What route?
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Indication: uterine hemorrhage resistant to Pitocin- causes uterine smooth muscle constriction and vascular smooth muscle constriction- CANNOT GIVE IV
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Normal fetal HR variability is ______ beats per minute
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6-15 bpm
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Fetal HR increases during contractions are considered
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Reassuring
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The neonate has ______% HgF
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75-84
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What are the four causes of postpartum hemorrhage?
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4 T's:
Tone (uterine hypotonia) Tissue (retained placenta or fragments) Thrombin (DIC) Trauma (uterine rupture) |
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Painful vaginal bleeding is a sign of
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Placental abruption
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Painless vaginal bleeding is a sign of
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Placenta previa
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Prostaglandin F2 Alpha (hemabate) causes
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Constriction of uterine, GI, bronchial and vascular smooth muscle
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Hemabate must be used with caution in
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asthmatics
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