SEE Obstetrics Anesthesia Review Flashcards
In pregnancy Cardiac output increases mostly because of an increase in _______.By how much does CO increase at term_____? SV by how mucH
an increase in stroke volume and, to a lesser extent, an increase in heart rate. SV 20-50%
CO increase by 40% at term
Blood volume during pregnancy (increase/decrease) , why ?By how much is it (increase/decrease)
Blood volume is markedly increased and prepares the parturient for the blood loss associated with delivery.
25-40%
Plasma volume during pregnancy? by what %?
What about blood cell volume? What %?
What does that cause? Total blood volume change?
Plasma volume is increased by 40-50%
Red Blood cell volume is increased by 20%
PV increase to a greater extent than red blood cell volume, resulting in a DILUTIONAL ANEMIA
Total blood volume increase by 25-40%
Minute ventilation during pregnancy and due to mostly
MV increases 45-50% (Nagelhout) and this is due mostly to an increase in tidal volume.
Oxygen consumption during pregnancy at rest? What about during labor?
Oxygen consumption is markedly increased by 33%; 100% during labor
Carbon dioxide production during pregnancy?
carbon dioxide production is similarly increased.
Pregnancy and Local anesthetics and MAC
Pregnant women have an increased sensitivity to local anesthetics and a decreased minimum alveolar concentration (MAC) for all general anesthetics.
What happens to Platelet count during pregnancy
remains stable or decreases slightly;
Coagulation factors and fibrinogen in pregnancy? What is the significance of the changes?
coagulation factors and fibrinogen are increased, resulting in a hypercoagulable state in pregnancy.
Major cause of Hypotension during pregnancy and how to relieve it?
Aortocaval compression results in profound hypotension and can be relieved by left uterine displacement.
All pregnant women are at increased risk of ______
aspiration
Because of the anatomic and physiologic changes to the gastrointestinal system with pregnancy, parturients should be considered to have a full stomach after what week?
weeks 12 of gestation vs 20 weeks
Pregnancy and labor and airway
associated with major airway changes that can result in a difficult intubation. This highlights the importance of a comprehensive airway evaluation prior to general anesthesia.
During pregnancy The heart rate (HR) is _____By ___% to _____% at term
increased by 20% to 30% at term.
Oxygen consumption increases by about how much in the full-term parturient?
33 percent in the full-term parturient, but minute ventilation increases by 50 percent at term. T
During pregnancy, the increased alveolar ventilation results in an
increase in the PaO2 to about 106 mmHg and a decrease in the PaCO2 to about 30-32 mmHg.
Pregnancy and plasma base
The plasma base (HCO3-) decreases from about 26 to 22 mEq/L, thus, the pH is essentially unchanged.
Provide analgesia by sparing motor blockade:
Ropivacaine
Bupivacaine
Endocrine hormones elevated with pregnancy
Total T3 and T4 (Not free )
Volume of the spinal CSF in pregnancy
Because the volume of epidural fat increases and epidural veins enlarge, the volume of spinal CSF is decreased in pregnancy.
Which anesthetic technique is most likely to reduce uterine blood flow in an obstetric patient?
Paracervical block
By the end of the first trimester, the cardiac output is How much greater than the non pregnant values?.
15-25 percent higher than nonpregnant values.
CO : 24 hours after delivery? When does it return to normal?
Cardiac output is still elevated for 24 hours after delivery and returns to normal slowly over a period of about 10 days
Despite the increased blood volume levels, plasma renin levels are
increased.
Can’t add bicarbonate to speed the onset of which LA ?
Although the addition of bicarbonate will speed the onset of a lidocaine epidural, the addition of bicarbonate to bupivacaine will cause it to precipitate.
Adding epinephrine or phenylephrine can enhance the ______of the anesthetic
Duration
Blood thinner that crosses the placenta in the greatest proportion?
Warfarin
Why is it recommended that an epidural anesthetic not be administered to a laboring parturient exhibiting cervical dilation less than 4 cm?
Dystocia
You have added an opioid to the local anesthetic used for a laboring parturient’s epidural. Where does the opioid exert its action?
The substantia gelatinosa
Airway resistance and pregnancy
NO CHANGE
Alveolar ventilation is increased by how much at term? what about FRC?
as much as 70% at term. The FRC decreases by 20-30%.
Follicular hyperplasia with pregnancy.
Follicular hyperplasia and increased vascularity result in a 50-70% increase in the size of the thyroid gland in pregnant patients.
Which of the following analgesics would be least appropriate to administer for postpartal pain control in a nursing mother?
Meperidine
What sensory level block would be appropriate for performing a cesarean section under epidural anesthesia?
T4
What are the 2 Coag. Factors decreased in pregnancy ?
Factors XI and XIII are decreased in pregnancy.
Factors that remains unchanged with pregnancy
II and V are unchanged.
Factors and pregnancy
Increased (factors I, VII, VIII, IX, X, and XII).
What hormone is responsible for the increased in Total T3 and T4 seen with pregnancy?
Estrogen
Which hormone is responsible for the increase in plasma volume during pregnancy?
Progesterone
Which hormone is responsible for the enhanced Renin-angiotensin- Aldosterone during pregnancy?
Progesterone
What happens gastric motility during pregnancy and which hormone is responsible?
Decrease gastric motility; Progesterone
What happens lower esophageal sphincter tone during pregnancy and which hormone is responsible?
Reduction of LES tone; Progesterone
PaCO2 levels increase or decrease during pregnancy? to what range? by what weeks does this change occur?
Decrease
30-32 mmHg
By 12 weeks of gestation
Electrolyte abnormality rarely seen and why?
Metabolic alkalosis because there is a compensatory decrease in serum bicarbonate form 26 to 22 mEq/L
Normal PaO2 during pregnancy : level is
Greater than 100 mmHg
Nonparticulate oral antacid no more than (timing) _____prior to surgery
1 hour before surgery
During C-section confirm block level at ______prior to surgical start
T4
Average blood loss C-section
500 -1000 ml
Normal Amniotic fluid volume is
700ml
Action of reglan
Increase gastric ph
enhance emptying
Creatinine levels during pregnancy
Decrease because of an increase in GFR
Pain pathways during labor: Area Uterus and cervix innervation
T10 to L1-L2
Pain pathways during labor: Area Perineum
S2 - S4
In the perineum: Pain impulses carried by
Somatic nerve fibers
Pudental nerve
Uterus and cervix pain impulses carried by
Visceral AFFERENT TYPE C fibers
Uterine blood flow at term increases to a max of _____
800 ml/min
Uterine blood flow at term accounts for how much of the maternal cardiac output
10%
Fetus send O2 poor blood to the placental via
2 umbilical arteries
Does UBF autoregulate?
No
Drugs characteristics that favor diffusion accross placenta : weight, solubility, ionization, protein binding
Low molecular weight (Less than 500 Da)
High lipid solubility
Low degree of ionization
Low protein binding
Drugs that do not cross: PHING
Protamine Heparin Insuline Neuromuscular Blocking agents Glycopyrollate
2nd stage of labor begins at _______ends
Full dilation 10cm
ends with delivery of the fetus
Meperidine cross placenta?
yes; although less likely than morphine in causing resp depression
Hallmark of PDPH
Lying Supine relieves pain
sitting and standing pain returns
Success rate of epidural blood patch
75%
Explains Epidural blood patch procedures
- Epidural needle is placed in the epidural space (same space better, or space below)
- Once needle is in place, assistant perform a peripheral venipuncture and draws aseptically 20 ml
- the blood slowly injected in epidural space 15-20 ml ideal
During epidrual blood pathc, back pain
Stop temporarily .
After epidural patch, pt should remain at rest for at least
1 hr
LAST early signs of toxicity
Circumoral numbness
lightheadedness
visual and auditory disturbances
Rapid response to LAST seizure
Give benzodiazepines
Preeclampsia definition
SBP > 140 or higher
DBP>90 or higher AFTER 20 weeks of gestation
ACCOMPANIED WITH PROTEINURIA.
Only definitive way of ending disease process of preeclampsia is
Delivery of the fetus.
3 risk factors for placenta previa
Uterine scars from prior uterine surgery
Prior placenta previa
Advance maternal age
Which one is more common accreta, increta or percreta
Accreta 70%
Maternal catastophes involving these 3 put the greatest risk to the fetus
Severe Hypoxia
Hypotension
Acidosis
Uterine blood flow formula
Uterine blood flow = Uterine arterial pressure - Uterine venous pressure / Uterine Vascular resistance
Any factor that causes maternal hypotension will _____uterine arterial pressure and thereby ______UBF
decrease; decrease
3 things cause by neuraxial anesthesia that can cause maternal hypotension
Aortocaval compression
Hypovolemia
Sympathetic blockade.
Other than a decrease uterine arterial pressure, what else can decrease UBF?
Increase uterine venous pressure (such as vena cava compression, seizure, valsava)
What are the elgot alkaloids?
Methylergonovine
Ergometrine
Dose of methylergonovine is ___ route?
0.2 mg IM
When can a second dose methylergonovine be given
2-4 hours.
3 oxytocic drugs used in OB
Oxytocin
Ergot Alklaoids (methylergonovine -methergine, ergometrine)
Prostaglandins (Carboprost)
Oxytocin should not be diluted with what solution
Hypotonic solution such as D5
First line of treatment for uterine atony
Oxytocin
Most common cause of hemorrhage
uterine atony
Oxytocin may precipitate (side effect):
Diastolic Hypotension
Flushing
Tachycardia (Nagelhout)
Most common used prostaglandin for treating pospartum hemorrhage?
carboprost (15-methyl prostaglandin)
What is the MAJOR ONLY ABSOLUTE contraindication to the use of Carbopost?
Can cause severe bronchoconstriction and airway hyperreactivity and should be used cautiously in patients with asthma.
Carboprost route and dosing
IM, 0.25 mg every 15 minutes up to 2mg.
Agent of choice for Oxytocic drugs
Oxytocin
5 patients who should not get ERGOT ALKALOIDS (methergine)
Preeclampsia eclampsia Hypertension Peripheral vascular disease CAD
VA concentration that reduces UBF
> 2 MAC
VA concentration that does not significantly affect UBF
0-5 - 1.5 MAC
Tocolytic drugs action
Relaxation of the uterine myometrium
Decreases uterine contractility
Uterus will continue to contract in the presence of Oxytocin provided that the MAC is less than
1 MAC
Tocolytic MOA
Limit calcium entry through L-type calcium channels.
Most commonly used CCB for preterm labor
Nifedipine
Magnesium sulfate used in the treatment of
Pre-eclampsia
Magnesium sulfate action at the NMJ
Competitive antagonists of calcium at the motor endplate reducing calcium influx into the myocyte
ACh release and magnesium sulfate
It decreases the release of ACh and decrease the sensitivity of the end plate to ACh
Magnesium in the presence of both NDNMB and DNMB?Dose should be ?
POTENTIATES action of Both NDNMBs and DNMNBs
Decreased ED50% by 25-50%.
Hypermagnesemia on MAC
Decreased MAC
COX inhibitors and pregnancy
Should be used in pregnancies beyond 32 weeks of gestation
Magnesium 3 classes
NMDA antagonists (fetal neuroprotection)
Tocolytic (
Anticonvulsant (in preeclampsia, eclampsia)
Magnesium, how does it affect calcium?
Block extracellular influx of calcium
Block intracellular release of calcium
Placental transfer of local anesthetics depends on what three factors?
1) pKa
2) maternal and fetal pH
3) degree of protein binding.
Most commonly used tocolytic is
Magnesium sulfate.
Overdose of Magnesium sulfate treated with
Calcium chloride
Bronchospasm refractory to SABA can also be treated with
Magnesium sulfate
Loss of DTRs occur with Mag levels of
4-5 mg/dL
Hypotension occurs at what magnesium levels
5-7 mg/dL
Heart block/ cardiac arrest occurs at what magnesium levels
10-15 mg/dL Heart block
10-24 Cardiac arrest.
Respiratory paralysis and coma occurs at what magnesium levels
10 mg/dL.
What are 2 Local anesthetics that do not cross placenta and why not?
Bupivacaine and Ropivacaine because of their HIGH degree of protein binding.
What Local anesthetic is least likely to have an effect on the fetus - and why?
Chloroprocaine
Because it is quickly broken down by maternal PSEUDOCHOLINESTERASE
Most commonly used anesthetic technique for C-section
Spinal
The most widely used agent and formulation used for spinal in the United States and why?
Agent: Bupivacaine
formulation : 0.75% in 8.25% Dextrose
Range of bupivacaine dose used in OB
9-12 mg
What are 3 reasons why the OB patients requires (less/more) ______dosing for spinal?
They require LESS
1) small CSF volume
2) cephalad movement of hyperbaric LA
3) Greater sensitivity of nerve fibers to LA during pregnancy
The most common solution used for initiation and maintenance of Epidural c-section delivery
lidocaine 2% with epinephrine 1: 200,000
The MOST RAPID onset of available epidural Local anesthetics
3% chloroprocaine.
Addition of epinephrine to local anesthetics leads to 3 benefits:
Less absorption and peak blood levels
increases density of sensory and motor blockade
prolongs duration of the epidural blockade.
APGAR scoring system is based on :
HR ( PULSE RR (Respirations) Muscle tone Reflex Color (Appearance)
When is APGAR scores measured?
1 minutes and 5 minutes
Normal APGAR
8-10
APGAR 4-7 indicates
Moderate distress
APGAR 0-3 indicates
Need for immediate resuscitation.
What is the preferred method of pain relief ?.
Early placement of continuous neuraxial analgesia is the preferred method of pain relief for the obese parturient
What three (3) maternal complications pose the greatest acute risks to the fetus during non-obstetric surgery during pregnancy?
Maternal complications involving severe hypoxia, hypotension, and changes in PaCO2 can all cause feta! asphyxia and pose the greatest acute risk to the fetus during non-obstetric surgery in the pregnant patient.
Which two general procedures are associated with the greatest risk of preterm labor in non-obstetric surgery during pregnancy?
Abdominal and pelvic procedures are associated with the greatest incidence of preterm labor. Intra-abdominal procedures during the third trimester are most likely to be associated with preterm labor
Procedure during 3rd trimester more likely to be associated with preterm labor?
Intra-abdominal procedures.
Which trimester is the safest to provide non -obstetric surgery and anesthesia for the parturient?
The second trimester is the safest to provide non-obstetric surgery and anesthesia for the parturient. and the 3•· trimester is the highest risk for preterm labor.
The first trimester non-ob surgery is the highest risk for
teratogenicity
Third semester is the highest risk for
Preterm labor.
What is the most common cause of maternal death during obstetric general anesthesia?
Hemorrhage.
Describe the use of a paracervical block during labor and delivery?
NOT used , because of high incidence of FETAL ASPHYXIA, fetal BRADYCARDIA and systemic anesthesia toxicity.
List two actions that should be taken if the newborn’s HR falls below 1OO bpm.
Begin positive-pressure face mask ventilation and Sp02 monitoring.
What intervention is recommended when the neonates HR falls below 60 bpm?
When an infant’s heart rate falls below 60 bpm,
Intubate if not already done
Continue positive pressure ventilation
Begin chest compressions and cardiac monitoring.
If a newborn has meconium and blood below the cords, what are the appropriate actions
Suction and intubate only if the newborn has a depressed Apgar score with meconium below the cords. Meconium stained amniotic fluid (MSAF) aspirated into the lungs can cause signifi-cant respiratory distress. Suctioning can be accomplished via the ETT. The neonate should be transferred to the NICU
What is an EXIT procedure and what are the anesthetic considerations?
EXIT stands for ex utero intrapartum procedure. This procedure involves surgical correction of a fetus during partial delivery.
The EXIT procedure is indicated in what instances?
where the fetus would not survive surgery after separation from uteroplacental support
Anesthetic considerations During EXIT procedure including.
maintaining uterine relaxation during fetal surgery and providing anesthesia for both mother and fetus. Volatile agents and IV narcotics that cross the placenta are used. Usually 2 anesthesia teams are needed, one for the mother and one for the fetus
A pregnant patient receives a saddle block and suddenly becomes agitated, dyspneic and unable to move her legs. She then becomes unconscious and apneic. Why?
High spinal. The key here is the motor paralysis, which indicates that the local anesthetic caused paralysis, which would not be seen with intravascu· tar injection
A pregnant patient receives a saddle block and suddenly becomes agitated, dyspneic and her legs thrash. Shortly after this, she becomes unconscious and apneic. Why?
Intravascular injection of local anesthetic may have occurred. These are signs and symptoms of seizures
What should be done once the diagnosis of placenta accreta is made?
What should you prepare for?
- rapid blood and fluid replacement prior to surgery
- placement of several large- bore intravenous catheters
- immediate availability of blood.
Ideal hospital setting for patient with placenta accreta?
Ideally patients with placenta accreta should be cared for in larger hospitals with access to a fully stocked blood bank and 24 hour in-house OB/Anesthesia services
The amniotic sac has ruptured (amnior- rhexis) in the parturient and is accompanied by bleeding and fetal heart rate deceleration. What should you suspect? Is this an emergency?
Whenever bleeding occurs with rupture of membranes in the parturient, particularly when accompanied by fetal heart rate deceleration or fetal bradycardia, vasa previa should be suspected. This is a true obstetric emergency as fetal mortality rates are high. ranging from 5O% to 75%.
Define vasa previa.
the fetal vessels traverse the fetal membranes ahead of the fetal presenting part
What happens to the fetal vessels during vasa previa?
the fetal vessels are not protected by the placenta nor the umbilical cord.
Risk factors for vasa previa
Risk factors for vasa previa are: ( I ) presence of placenta previa; (2) a low-lying placenta in the second trimester; (3) placental accessory lobes; (4) in vitro fertilization; and, (5) multiple gestations.
Describe the management of vasa previa.
Vasa previa is a true obstetric emergency that requires immediate delivery of the fetus
Almost always by the abdominal route and under general anesthesia. Neonatal resuscitation requires immediate attention to neonatal volume replacement with colloid, balanced salt solutions, and blood.
Consider the pregnant patient who is attempting a trail of labor {TOLAC) for vaginal birth after cesarean section {VBAC): what is a major concern?
Uterine rupture causes a rapid exsanguination and is a life-threatening potential complication that may occur with vaginal birth after cesarean section (VBAC).
Incidence of Uterine rupture during VBAC
The incidence of uterine rupture with VBAC labor is higher than once thought, now approaching 2%. Fetal mortality is almost 80%.
What are the two (2) leading causes of peripartum hemorrhage?
UTERINE ATONY
Placenta Accreta
What causes fetal acidosis? What problems will be seen in the fetus?
Fetal asphyxia leads to rapid decreases in fetal pH. Hypoxia and acidosis cause a shift to the RIGHT in the fetal oxyhemoglobin dissociation curve. The fetus will have deceased oxygen delivery, increased systemic vascular resistance, and depression of the myocardium.
You are confronted with an unexpected difficult intubation of the pregnant patient. After induction, you are unable to intubate the trachea via multiple techniques. Mask ventilation remains adequate and there is NO fetal distress. What are your options?
If there is no fetal distress, awaken the patient. Consider awake intubation or regional anesthesia unless contraindicated.
You are confronted with an unexpected difficult intubation of the pregnant patient. After induction, you are unable to intubate the trachea via multiple techniques. Mask ventilation is adequate, but fetal distress IS present. What are your options?
Continue anesthesia by mask ventilation while an assistant maintains cricoid pressure
Provide sevoflurane with spontaneous ventilation if possible.
Attempt placement o f LMA and if possible attempt to pass the ETT via the LMA. If the airway becomes inadequate, invasive airway techniques may be required to support the parturient during delivery of the fetus in distress.
List five(5 )specific actions in treating amniotic fluid embolism
Treatment of amniotic fluid embolism consists of aggressive cardiopulmonary resuscitation, stabilization and supportive care.
(1) Intubate and ventilate with 100% 02
(2) begin cardiopulmonary resuscitation if there is no pulse
(3) insert two large bore intravenous lines, an arterial line, a bladder catheter, and consider pulmonary artery catheter placement
(4) monitor Sa02, EKG, pulmonary and systemic blood pressures, cardiac indices, and neurologic function, and (5) notify the blood bank
Gold standard anesthesia for patient with Aortic stenosis
GA
The patient has a prolonged labor and difficult vaginal delivery. At the end of the case the patient is unable to dorsiflex the foot, what nerve was most likely injured?
The common peroneal nerve. This nerve can be compressed between the head of the fibula and a lithotomy stirrup when the patient is in the lithotomy position, or from prolonged squatting.
Foot drop or Inablity to dorsiflex foot is caused by
Common peroneal nerve injury.
When is ketamine used for cesarean section? Specify the ketamine dose
Ketamine (1 mg/kg) is preferred for induction if the mother is hypovolemic due to its hypertensive effects. The maximum dose of ketamine for rapid sequence induction of the parturient is l mg/kg. At higher doses, ketamine increases uterine tone and could endanger the fetus . Ketamine crosses the placenta due to its high lipid solubility
Why is sodium bicarbonate routinely added to prepackaged lidocaine with epinephrine for epidural anesthesia prior to cesarean section?
Alkalization of the local anesthetic hastens the onset of neural block and improves the quality of the block. Adding sodium bicarbonate increases the amount of drug in the lipid soluble form (non- ionized form), thus increasing the rate of diffusion across lipid membranes.
Sodium bicarb cannot be added to ________as it will precipitate.
Sodium bicarb cannot be added to bupivacaine as it will precipitate.
Name 3 advantageous effects of magnesium sulfate in pregnancy.
Magnesium sulfate is a tocolytic, an anticonvulsant, and a fetal neuroprotective agent
What is the effect of intravenous (IV) lidocaine on uterine blood flow?
All local anesthetics can reduce uterine blood flow at HIGH plasma concentrations. High doses of IV lidocaine cause uterine arterial vasoconstriction and increased uterine tone
What is the key determinant of the amount of drug transferred across the placenta?
The maternal blood concentration of free drug is the primary determinant of the amount of drug transferred across the placenta.
Remember : Higher doses result in_______ maternal blood concentrations
higher
Common drugs anticholinergics that cross the placenta
Atropine
Scopolamine
Common drugs BP meds that cross the placenta?
Nitroprusside
Nitroglycerin
Beta Blockers
Common drugs IV anesthetic drugs that cross the placenta
Midazolam Ketamine Propofol Etomidate Opioids
VA cross placenta
All
Why is hydralazine a commonly used antihypertensive in preeclampsia?
Hydralazine is vasodilator that also increases uteroplacental flow and renal blood flow. Nitroglycerine and labetalol are also commonly used.
Is regional safe in preeclamptic patient?
Provided no severe clotting deficit or plasma volume deficit, regional anesthesia can be safely used in the preeclamptic patient.
The patient with preeclampsia is in danger of developing serious complications. Name eight (8) serious complications of preeclampsia.
1) Pulmonary edema; (2) airway obstruction; (3) placental abruption; {4) cerebral hemorrhage: (5) cerebral edema: (6) disseminated intravascular coagulopathy: (7) HELLP syndrome; (8) renal failure; and, {8} CHE (
What is the cause of preeclampsia?
The hallmark of preeclampsia is an abnormal placental implantation. This abnormal placenta releases vasoactive substances causing dysfunction of the maternal vasculature.
Risk factors for preedampsia?
Nulliparity
Family hx of preeclampsia
Advanced maternal age.
Chronic HTN
Define gestational hypertension.
Gestational hypertension, or pregnancy induced hypertension (PIH) is blood pressure of 140/90 and above in an otherwise healthy woman after the 19” week of gestation.
Which of the following are recommended infusion rates for continuous epidural analgesia for a laboring parturient? (select two)
Bupivacaine 0.0625% to 0.125%
Topivacaine 0.1-0.2% can be administered at a rate of 8-12 mL/hour to provide continuous analgesia during labor.
Methods by which small ions, respiratory gases, and most drugs under 600 daltons cross placenta is 4) Facilitated diffusion, which is mediated by a carrier and includes substances such as glucose.
Passive transport,
Transport method by which amino acids, vitamins, calcium, and iron cross placenta>
Active transport
Methods by which larger molecules such as immunoglobulins cross the placental barrier
Pinocytosis.
Transport which is mediated by a carrier and includes substances such as glucose cross placenta
Facilitated diffusion
The most popular opioid agonist-antagonists are ___ _and_____ for labor analgesia due to their
butorphanol and nalbuphine
Proposed benefits of opioid agonist-antagonists including 3 benefits?
less nausea, vomiting, and dysphoria.
During the active stage of labor, pain is referred to the ____ spinal cord segments.
T10 - L1
What is the advantage of combining opioids with local anesthetics in combined spinal/epidural analgesia?
it improves anesthesia without significant motor block
Comment on Albumin and alpha-1 acid glycoprotein in regards to pregnancy
Drugs that bind to albumin cross the placenta more easily because they have a lower binding affinity.
Drugs that bind to alpha-1 acid glycoprotein are more ‘tightly’ bound. As a result, less of the drug is released from the protein and made available for transport across the placental membrane.
A postpartum patient presents for a tubal ligation. What is the most common form of anesthesia for this procedure?
Local anesthesia
3 drugs when given to mother can both produce fetal vasodilation, but clonidine does not.
Magnesium and nifidipine, and Enalaprilate
ACEI and enalaprilate?
ACE inhibitors also cross the placenta. Enalaprilat has been shown to reduce fetal arterial pressure by 20%.
Maternally administered meperidine can produce ____ and _____in the fetus.
decreased beat-to-beat variability and tachycardia in the fetus.
Does clonidine cause fetal vasodilation?
No
What % of fentanyl would cross the placenta?
Fentanyl is 60-80% percent protein bound, which means that about one-third of the drug is circulating free in the plasma available to cross the placenta.
Plasma cholinesterase activity during pregnancy? how is succinylcholine affected
Plasma cholinesterase activity decreases by about one-third by the second trimester. The duration of action of succinylcholine is rarely affected, however.
Plasma renin activity and pregnancy
Renin levels increase despite the increase in blood volume and that is due to Progesterone.
EF during pregnancy
Increased
Which one increase or decrease during pregancy left ventricular end-diastolic volume increases vs The left ventricular end-systolic volume increases
The left ventricular END-DIASTOLIC volume increases during pregnancy, but there is no change in the end-systolic volume.
RSI recommended after how many weeks?
20
Functional choanal atresia results from 3 things? how is it treated?
blood, meconium, or mucus blocking the nasal passages. It would be treated by nasal suctioning.
What is the most reliable test for detecting an inadvertent intrathecal or intravascular epidural catheter placement in a laboring parturient?
Negative aspiration for CSF or blood
Although epinephrine reliably increases the heart rate in pregnant patients, it is less
specific in laboring patients because the heart rate varies widely during and between labor contractions.
How are the pudental nerves blocked? What ligaments?
The nerves are blocked by injecting 10 mL of local anesthetic behind each sacrospinous ligament
Most commonly administered inhalation agent for analgesia during labor?
Nitrous
How long after delivery does the cardiac output of the mother remain elevated?
2 weeks (14 days)
The leading cause of anesthesia-related mortality associated with cesarean delivery?
Intubation failure
Incidence of hydronephrosis during preganncy
The incidence of hydronephrosis is 80% in pregnant patients.
What causes the 80% of patients to have hydronephrosis?
The increased blood and interstitial volume produce a compensatory increase in renal volume. The urinary collecting system (collecting ducts, calcyes, renal pelvis, and ureters) dilate substantially, producing hydronephrosis in 80% of pregnant women by mid-term.
Peripheral vascular resistance in pregnancy (increase/decrease)_
Decrease
Hgb in pregnancy (increase/decrease)_to what levels?
Decrease; 11-12 g/dL
GFR in pregnancy (increase/decrease) by what %?
Increase by 50%
You are administering 10 mL of chloroprocaine 2% via an epidural. What approximate duration of action would you expect from this dose?
40 minutes
The epinephrine in an epidural test dose is less reliable in which patient class?
Patients in ACTIVE LABOR.
Which physiologic characteristic (heme) would you expect to be doubled by term in an obstetric patient?
FIBRINOGEN
SVR % change during pregnancy at term
Decrease by 20%
Why is GFR increase during pregnancy?
Due to an increase in CO
Tidal volume at term
Increase by 40%
FRC at term
Decrease by 20%
You are preparing to perform a general anesthetic for appendectomy on a parturient in her second trimester. You know that this patient will exhibit a _____ induction and a _____ emergence from inhalation anesthesia.
Faster and faster
(Pregnancy produces an increase in the minute ventilation and a decrease in the functional residual capacity. That, combined with a decrease in MAC, results in both a faster inhalation induction AND a faster emergence from anesthesia. The MAC generally begins to decrease by the 8th or 10th week of pregnancy).
You are preparing to perform a caudal block on a neonate. What is the maximum bolus dose of bupivacaine you should administer to this patient?
2 mg/kg; Older children 4mg/kg
