02.25.2021: OB & Peds

Which of the following drugs would cross the placenta more easily?

-Drugs with no ionic charge -Drugs that bind to albumin -Uncharged molecules cross the placenta more easily. 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.

Which anesthetic technique is most likely to reduce uterine blood flow in an obstetric patient?

-Administration of a paracervical block -Local anesthetics exert a vasoconstrictor property that can reduce uterine blood flow. The normal concentrations used do not normally have this effect with two exceptions: 1) inadvertent intravenous injection of a local anesthetic, and 2) paracervical block. Bupivacaine exerts a greater vasoconstrictor effect than either chloroprocaine or lidocaine.

Which of the following should take priority in your airway management plan for a pediatric patient with bronchopulmonary dysplasia?

-Choose an endotracheal tube that has an internal diameter 0.5-1.0 smaller than normal -Patients with bronchopulmonary dysplasia (BPD) exhibit airway hyperreactivity and need a deep plane of anesthesia prior to intubation. Because subglottic stenosis may be present, you should choose an endotracheal tube that is 0.5-1.0 smaller than normal for the patient's age. Diuretics are sometimes needed to treat pulmonary edema for these patients, but preventive administration of diuretics would be inappropriate. You should delivery oxygen in a concentration sufficient to maintain a PaO2 of 50-70 mmHg.

Because preterm infants have a limited ability to perform glucuronidation, they would likely exhibit a prolonged duration of action of which of the following drugs?

-Morphine -Term and preterm infants cannot metabolize morphine as effectively as children and adults. Neonates have a limited ability to perform glucuronidation. Because morphine undergoes glucuronidation, the active form of the drug will be present in the circulatory system for a longer period of time.

Which of the following statements regarding drug responses in term neonates is accurate?

-Neonates exhibit resistance to the cardiac effects of dopamine -Infants (both preterm and term) have a higher proportion of water compared to their body mass. As a result, the volume of distribution for water-soluble drugs is greater. Because of this, they often require a higher loading dose of water-soluble drugs such as digoxin, succinylcholine, and some antibiotics (such as aminoglycosides). Myocardial concentrations of digoxin can be as much as 6 times higher than that of adults at the same serum concentration. Term neonates exhibit resistance to the cardiac effects of dopamine and may not exhibit increased blood pressure and urine output until doses of 50 mcg/kg/min are reached.

A breathing pattern in an infant that consists of recurrent pauses in ventilation that last no longer than 5-10 seconds is consistent with a diagnosis of

-Periodic breathing consists of recurrent pauses in ventilation that last no longer than 5-10 seconds. This pattern of breathing often occurs during REM sleep and is not associated with any physiologic disorder. -Apnea of prematurity, however, is associated with prolonged ventilatory pauses that are significant enough to produce arterial hypoxemia and bradycardia. -Both are more common in premature infants.

Which of the following statements is true regarding the cardiac system of the premature infant?

-The heart has a greater dependence upon extracellular calcium concentrations -The fetal heart contains more connective tissue, the contractile elements are less organized, and contractility has a greater dependence upon the extracellular calcium concentration. Autoregulation is not yet matured, so the heart rate does not respond sufficiently to hypovolemia. The heart of the premature infant is less sensitive to catecholamines because it is already near the maximum level of beta-adrenergic stimulation. Digitalis is contraindicated in premature infants because no resulting increase in contractility or ventricular ejection occurs, but the heart rate does slow down, resulting in a decrease in cardiac output.

Which of the following is greater in a healthy two year-old patient than it is in an adult

-The volume of distribution of propofol -The bioavailability of intramuscular ketamine -Protein binding is decreased in preterm and term infants but is similar between children and adults. The bioavailability of ketamine is high in adults (93%) but is even higher in children. By 6-12 months of age, the clearance of morphine is equal to that of adults. The volume of distribution of propofol is larger in children than adults.

Which of the following would you expect to be increased in a healthy, 7 year-old child when compared to an adult patient?

-Total body clearance of cisatracurium -The bioavailability of ketamine -The volume of distribution and the total body clearance are both significantly greater in pediatric patients, which accounts for the faster recovery in children. By 6-12 months of age, the clearance of morphine is equal to that of adults. The bioavailability of ketamine is high in adults (93%) but is even higher in children. Premedication with ketamine has been shown to reduce the incidence of emergence delirium in pediatric patients.

In the past, a common technique for maintenance of general anesthesia during a c-section was to combine 50:50 nitrous oxide and oxygen with 0.5 MAC of a volatile anesthetic. This technique is associated with a high risk of

-awareness during anesthesia -In the past, it was common to maintain anesthesia with 50:50 nitrous and oxygen with 0.5 MAC of a volatile agent to limit fetal exposure to the volatile anesthetic. This technique is associated with a high incidence of awareness, however, and higher concentrations of the volatile agent are now recommended.

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, 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.

An advantage of a combined spinal epidural over an epidural only for cesarean section is

-less shivering -A combined spinal-epidural (CSE) for c-section provides the advantages of a rapid onset, dense block, and the ability to augment the duration of the anesthetic. The incidence of shivering and breakthrough pain is less with a CSE than for an epidural only.

Compared to the adult, the neonatal

-myocardium is more sensitive to norepinephrine -Because of their high metabolic demand, the cardiac output of a neonate relative to weight is about twice that of an adult. Most of the cardiac output increase is due to a heart rate that averages 140 BPM. Because the sympathetic innervation is not yet matured, the neonatal myocardium is less sensitive to dopamine, but more sensitive to norepinephrine.

A continuous spinal anesthetic is typically not the first choice for labor analgesia because of the high risk for

-post dural puncture headache -Continuous spinal anesthesia using a macro-bore catheter may be useful in high-risk patients such as the morbidly obese or patients with severe spinal deformities. Because of the risk of dural puncture (and subsequent postdural puncture headache) by the epidural catheter used to thread the macrobore catheter, a continuous spinal anesthetic is not considered a first choice for anesthesia for labor.

You are performing a combined spinal-epidural for an obstetric patient in the first stage of labor and administer fentanyl 25 mcg intrathecally. You know that the incidence of delayed-onset respiratory depression from rostral spread of the drug is most common

-within the first 30 minutes of administration -Intrathecally-administered opioids can occasionally spread in a rostral fashion and produce delayed-onset respiratory depression. This rarely happens with fentanyl and sufentanil, but when it does, the incidence is greatest within the first 30 minutes after injection.

Which compensatory thermoregulatory mechanism does a full-term neonate possess?

2-degree Celsius difference between the skin and core temperature results in the release of norepinephrine which stimulates the lipolysis of brown fat. The side effects of nonshivering thermogenesis are increased oxygen consumption and the production of ketone bodies and water. This has a tendency to produce a metabolic acidosis and osmotic diuresis, both of which are disadvantageous. Every attempt should be made to regulate the neonate's core temperature to prevent nonshivering thermogenesis.

What infusion dose of propofol is required to produce general anesthesia in pediatric patients?

250 mcg/kg/min is sufficient in the pediatric population to produce general anesthesia for painless medical or radiolologic procedures, but the dose may have to be increased to prevent movement.

The 12-lead ECG of a parturient in the third trimester would most likely exhibit

As the patient gets closer to term, the diaphragm rises and shifts the heart upward and leftward. This makes the heart appear larger on chest xray and produces a left axis shift on the ECG. In the third trimester, there is also an increased tendency for premature atrial contractions, supraventricular tachycardia, and ventricular dysrhythmias.

Compared to adults, neonates exhibit a(n)

Compared to adults, neonates exhibit increased total body water, increased extracellular fluid volume, a decreased glomerular filtration rate, and a decreased ability of the renal tubules to absorb sodium, bicarbonate, glucose, and amino acids.

Which of the following is true regarding the use of ketamine in obstetric patients?

Ketamine is very lipid soluble and quickly crosses from the placenta to the fetus. Induction doses of 0.5-1 mg/kg, however, does not compromise neonatal status at delivery. Uterine blood flow is maintained as well as uterine tone. Induction doses of 2-2.5 mg/kg result in a depressed neonate upon delivery.

Using normal concentrations and dosages, which type of local anesthetic administration would be most likely to affect uterine blood flow?

Local anesthetics exert a vasoconstrictor property that can reduce uterine blood flow. The normal concentrations used do not normally have this effect with two exceptions: 1) inadvertent intravenous injection of a local anesthetic, and 2) paracervical block. Bupivacaine exerts a greater vasoconstrictor effect than either chloroprocaine or lidocaine.

Which of the following is a predictor of difficult epidural placement in obese parturients?

Studies have shown that the ability to palpate bony landmarks and the ability of the patient to flex their back were predictive of difficulty in placing an epidural in a parturient. The body mass index of the patient and the experience level of the practitioner were not predictive of difficulty

You are preparing to administer ketamine orally to a 33 pound three year-old. Which of the following doses would be appropriate?

5-6 mg/kg is the appropriate dose for orally administered ketamine in patients from 1 to 6 years of age.

What is the lower limit of autoregulation of cerebral blood flow in children of all ages?

60 mmHg is the lower limit of autoregulation of CBF in children of all ages.

When does the anterior fontanelle normally close?

9 and 18 months of age.

Which of the following blocks is useful for pain control in a parturient in the first stage of labor?

A paravertebral lumbar sympathetic block can often be used to provide analgesia during the first stage of labor when contraindications to traditional neuraxial analgesia exist. It blocks the transmission of painful stimuli from the cervical and uterine nerves.

In general, regional anesthesia is not contraindicated in obstetric patients with mild preeclampsia if the platelet count is at least

A platelet count less than 75,000-80,000 is considered too low to perform a neuraxial anesthetic.

What are the three most common entry sites for an amniotic fluid embolism?

The placenta, endocervical veins, and a uterine trauma site are the three most common entry sites for an amniotic fluid embolism.

What is the preferred position for a noninvasive blood pressure cuff in an infant with a patent ductus arteriosus?

The preferred placement of a noninvasive blood pressure cuff in pediatric patients is the upper extremity because it most closely mirrors cerebral perfusion. This becomes even more significant in neonates under 1000 grams. If a patent ductus arteriosus is present, the pressure should be taken in the right arm to provide the most accurate representation of cerebral perfusion.

Which modalities are commonly used in the treatment of apnea in the premature infant?

The primary treatment modalities for apnea in premature infants are CPAP and methylxanthines such as caffeine.

What is the recommended dose of intravenous nalbuphine in a laboring parturient?

The recommended dose of nalbuphine is 10 mg IV or IM.

In pregnancy, insulin resistance

The release of the hormone lactogen by the placenta causes an increase in insulin resistance during pregnancy.

Which of the following is not a risk factor for the development of preeclampsia?

Tobacco (smoking) is the most frequently abused substance among pregnant patients. Studies show that smoking is protective against the development of preeclampsia.

You are preparing to anesthetize a pediatric patient with Arnold-Chiari malformation. Which of the following is true regarding the care of a patient with this condition?

Arnold-Chiari malformation almost always coexists with myelodysplasia and involves the caudal displacement of the cerebellar vermis, fourth ventricle, and lower brainstem below the level of the foramen magnum. Medullary cord compression can occur, particularly with extension of the neck, and patients may present with symptoms such as vocal cord paralysis, swallowing dysfunction, and chronic pulmonary aspiration. Surgical correction is usually performed by a decompressive suboccipital craniectomy with cervical laminectomies to relieve the compression. Because of cranial nerve and brainstem dysfunction, children with this disorder may have abnormal responses to hypoxia and hypercarbia.

When should chest compressions be initiated in the neonate?

After ventilation with oxygen for 30 seconds, chest compressions should be initiated in the neonate when the heart rate is less than 60 bpm.

Which of the following statements concerning respiratory changes during pregnancy is true?

Airway resistance stays roughly the same because of the competing effects between the relaxation of bronchiolar smooth muscle by progesterone versus factors such as upper airway edema. Minute ventilation increases significantly during pregnancy. Because dead space doesn't change, alveolar ventilation is increased by as much as 70% at term. The FRC decreases by 20-30%.

What is the predominant serum protein in fetal blood?

Alpha-1 fetoprotein is the predominant serum protein in fetal blood.

An obstetric patient has a mechanical heart valve. Which of the following statements is most consistent with recommended anticoagulation objectives for this patient?

Anticoagulation is a concern for parturients presenting with mechanical prosthetic valves. Current anticoagulation options for pregnancy per the American College of Cardiology are as follows: 1. Warfarin should be continued until week 36; Convert to unfractionated heparin or low molecular-weight heparin at that point 2. Use low molecular-weight heparin for entire pregnancy 3. Use low molecular weight heparin or unfractionated heparin from 6 to 12 weeks and also after week 36; use warfarin from 12 to 36 weeks.

Which of the following agents and doses would be appropriate for the reversal of neuromuscular blockade of rocuronium in an infant?

Traditional doses of neostigmine (50-60 mcg/kg) or edrophonium (500-1000 mcg/kg) combined with glycopyrrolate 0.2 mg per 1 mg of neostigmine are appropriate for reversing neuromuscular blockade in infants. Physostigmine and pyridostigmine are not traditionally used for reversal of neuromuscular blockade.

A patient with cardiomyopathy of pregnancy is scheduled for a cesarean section. Which intervention would be least appropriate for this patient?

Treatment of cardiomyopathy of pregnancy involves therapies to increase myocardial contractility, optimize preload, reduce afterload, and for many patients, thromboprophylaxis. Anesthetics in this patient population should be directed towards reducing and avoiding cardiac stress.

How are thyroid hormones altered by pregnancy?

Because of the estrogen-induced increase in thyroid-binding globulin, the concentrations of both the T3 (triiodothyronine) and T4 (thyroxin) concentrations increase by about 50%. Follicular hyperplasia and increased vascularity result in a 50-70% increase in the size of the thyroid gland in pregnant patients.

You are administering nalbuphine to a laboring patient. Which of the following statements regarding this drug are true?

Both nalbuphine and butorphanol have lower incidences of nausea, vomiting, and dysphoria. They also have a ceiling effect on the degree of respiratory depression they produce. Their metabolites are inactive.

Bradycardia in a three year-old is considered to be any heart rate less than

Bradycardia for infants (<1 yr of age) is 100 bpm; young children 1 to 5 years of age is 80 bpm; and for children >5 years of age is 60 bpm

Which of the following pediatric conditions is most associated with airway hyper-reactivity?

Bronchopulmonary dysplasia is one of the long-term potential consequences of the respiratory distress syndrome seen in premature infants. It is characterized by a chronic disorder of the lung parenchyma that involves hyperplasia of the smooth muscle tissue of the airways, peribronchiolar fibrosis, enlarged alveoli, and abnormalities in the pulmonary vasculature. Airway hyperreactivity is often present and requires treatment with bronchodilators.

Which physiologic characteristic would you expect to be doubled by term in an obstetric patient?

By term, plasma volume increases by about 40 percent, hemoglobin decreases to 11-12 g/dL, cardiac output increases by 30-50 percent, and fibrinogen doubles.

Which of the following statements regarding obstetric patients is true?

By the end of the first trimester, the cardiac output is 15-25 percent higher than nonpregnant values. Cardiac output is still elevated for 24 hours after delivery and returns to normal slowly over a period of about 10 days (some references state it may take as long as 3 months for the cardiac output to return to prepregnancy values). Despite the increased blood volume levels, plasma renin levels are increased.

You are administering 10 mL of chloroprocaine 2% via an epidural. What approximate duration of action would you expect from this dose?

Chloroprocaine has a rapid onset and a short duration of action. 10 mL of 2% chloroprocaine would last approximately 40 minutes.

Which of the following laboratory values tends to be decreased in full-term parturients?

During pregnancy, liver enzymes such as lactate dehydrogenase, alkaline phosphatase, aspartate aminotransferase, and alanine aminotransferase all increase to the upper limits of normal. Serum albumin levels decrease, which can increase the free fraction of protein-bound drugs.

Pregnancy typically produces

During pregnancy, the glomerular filtration rate increases from about 140 ml/min to 160 mL/min as a result of the increased cardiac output. The blood urea nitrogen levels decreases to about 8 mg/dL, and the serum creatinine drops to approximately 0.5 mg/dL as a result.

Children who have had recent upper respiratory tract infections should not undergo elective anesthesia for at least

Elective anesthesia should be delayed at least 4 weeks for children who have had recent URTI to ensure resolution of the pathologic effects in the small airways.

You have administered ephedrine 10 mg IV to treat hypotension in a laboring parturient. How long would you expect the effects of the drug to last?

Ephedrine 5-10 mg IV typically lasts about 5 minutes.

Which of the following is increased during pregnancy?

Estrogen induces an increase in total T3 and T4 levels by the end of the first trimester. Skeletal calcium is resorbed to meet the demands of the fetus. Because the volume of epidural fat increases and epidural veins enlarge, the volume of spinal CSF is decreased in pregnancy. The size of the liver does not change with pregnancy.

The most common airway problem in pediatric patients is upper airway obstruction due to

Upper airway obstruction due to laryngomalacia is the most common airway problem in pediatric patients.

Which pediatric condition would require surgical intervention the soonest after delivery?

Gastroschisis, omphalocele, congenital diaphragmatic hernia, tracheoesophageal fistula, intestinal obstruction, and myelomeningocele are all typically repaired within the first week following delivery. Pyloric stenosis, necrotizing enterocolitis, ligation of a PDA, and inguinal hernia repair are typically addressed within the first month of life.

Match the agent with the effect it has on placental arterial pressure when administered to a parturient.

Greatest Increase to Ephedrine Lesser increase to Phenylephrine No effect to Epinephrine Decrease to Enalaprilat.

What side effect would you most expect to see from high doses of oxytocin?

High doses of oxytocin can produce diastolic hypotension (and some degree of systolic hypotension), flushing, and tachycardia.

A patient with primary pulmonary hypertension is scheduled for a cesarean section under general anesthesia. Which of the following anesthetics would be least appropriate for this patient?

It is a source of debate as to how these women should deliver. Scheduled cesarean sections allow for optimal conditions, however patients experience more variability in hemodynamics. Epidural and general anesthesia have both been utilized; however, spinal anesthesia is not recommended because it produces sudden decreases in SVR. General anesthetics pose the risks of increasing pulmonary artery pressure during airway instrumentation, decreasing venous return through positive pressure ventilation, and reducing cardiac contractility through the use of volatile gases. Nitrous oxide should not be used as it can exacerbate increases in pulmonary vascular resistance. Drugs such as calcium channel blockers, isoproterenol, inhaled nitric oxide, or sildenafil may be used to decrease the pulmonary vascular resistance.

What is the caution regarding the use of intranasal ketamine?

Ketamine has been shown to enter the central nervous system directly when given via the intranasal route because it can track along neurovascular tissues in the nasal mucosa. The preservative in ketamine is neurotoxic and the possibility of CNS toxicity exists with the administration of intranasal ketamine.

Which drugs cause vasodilation in the fetus when administered to the mother?

Magnesium and nifidipine both produce fetal vasodilation, but clonidine does not. ACE inhibitors also cross the placenta. Enalaprilat has been shown to reduce fetal arterial pressure by 20%.

Which of the following agents decrease uterine blood flow?

Magnesium increases uterine blood flow in both hypertensive and normotensive subjects. Even though it may magnify hypotension in patients undergoing epidural anesthesia, magnesium still does not decrease uterine blood flow. Sevoflurane, isoflurane, and desflurane have been shown to exert no change on uterine blood flow between 0.5 and 1.5 MAC. Although with higher levels of inhaled anesthetic (2 MAC or greater), uterine blood flow may be decreased, there have been no reports of impaired fetal gas exchange. Verapamil 0.2mg/kg has been shown to decrease maternal blood pressure and decrease uterine blood flow. Local anesthetics exert a vasoconstrictor property that can reduce uterine blood flow. The normal concentrations used do not normally have this effect with two exceptions: 1) inadvertent intravenous injection of a local anesthetic, and 2) paracervical block. Bupivacaine exerts a greater vasoconstrictor effect than either chloroprocaine or lidocaine.

Which of the following agents does not produce fetal vasodilation?

Magnesium, nifidipine, and enalaprilat produce fetal vasodilation, but clonidine does not.

Manifestations of preeclampsia include

Manifestations of preeclampsia include: hypertension, hypovolemia, oliguria, decreased colloid oncotic pressure, pulmonary edema, arterial hypoxemia, decreased uterine blood flow, disseminated intravascular coagulation, cerebral edema, cerebral hemorrhage, acute tubular necrosis, and HELLP syndrome (hemolysis, elevated liver enzymes, low platelets).

What are the expected effects of maternally administered meperidine on the fetus?

Maternally administered meperidine can produce decreased beat-to-beat variability and tachycardia in the fetus.

Which of the following routes of administration of midazolam would be least recommended for a five year-old patient?

Midazolam can be administered oraly, rectally, nasally, intravenously, or intramuscularly. The IM route is not recommended because of pain and the risk of a sterile abscess.

The most common surgical emergency in the neonate is

Necrotizing enterocolitis is the most common surgical emergency in the neonate. Premature infants are at the greatest risk for developing it. Conditions associated with necrotizing enterocolitis include umbilical artery catheterization, systemic infections, perinatal asphyxia, hypotension, exchange blood transfusions, patent ductus arteriosus, cyanotic heart disease, respiratory distress syndrome, and hyperosmolar feedings.

Which epidural adjuvant agent is believed to promote analgesia by binding to muscarinic receptors?

Neostigmine binds to muscarinic receptors and promotes analgesia by decreasing neurotransmitter release in the spinal cord when combined with epidural local anesthetics.

Which of the following decreases with pregnancy?

Plasma cholinesterase activity decreases by about one-third by the second trimester. The duration of action of succinylcholine is rarely affected, however. The increase in cardiac output increases renal blood flow and the glomerular filtration rate. BUN and creatinine both decrease as a result. The increased renal blood flow can result in the renal excretion of small amounts of glucose and protein. Liver enzymes are increased slightly by pregnancy.

During what period following general anesthesia are premature neonates most likely to exhibit apnea and bradycardia?

Postoperative apnea and bradycardia is most likely to occur in neonates who were premature, those with multiple congenital anomalies, those with lung disease, and those with a history of apnea and bradycardia. The risk is highest in the first 4-6 hours after surgery, but can still occur for up to 12 hours postoperatively. The conservative approach is to monitor all infants younger than 60 weeks postconceptual age overnight.

The leading cause of maternal death worldwide is

Responsible for 25% of all maternal deaths, hemorrhage is the leading cause of maternal mortality. There are four categories of hemorrhage in obstetrics: abnormal tissue (placenta), abnormal tone (uterus), abnormal coagulation, and trauma. Postpartum hemorrhage is considered to occur when more than 500 mL of blood is lost from a vaginal delivery or more than 1000 mL from a cesarean section.

Midazolam can be administered oraly, rectally, nasally, intravenously, or intramuscularly. The IM route is not recommended because of pain and the risk of a sterile abscess.

Retinopathy of prematurity has been shown to be related to supplemental oxygen therapy, low birth weight, postnatal hypotension, the use of surfactant or inotropes, and mechanical ventilation.

An obstetric patient with a functioning epidural undergoes emergency cesarean section due to placental abruption. During the procedure, she suddenly exhibits anxiety and dyspnea that progresses to cardiovascular collapse. The cause that would most likely explain this is

Risk factors include placental abruption, abnormal placentation, eclampsia, surgical delivery, and spontaneous rupture of membranes. Parturients suffering from an amniotic fluid embolism experience sudden hypotension, anxiety, dyspnea, hypoxia, and eventually cardiovascular collapse and coagulopathies.

Ropivacaine is better suited than bupivacaine for a lumbar epidural for a laboring parturient because

Ropivacaine produces less motor block than bupivacaine, causes less CNS and cardiac toxicity, and has an elimination half-life of 5.2 hours compared to 10.9 hours for bupivacaine.

Which of the following fetal alterations would be least likely to occur as a result of fetal asphyxia?

Severe fetal asphyxia can develop from complications such as maternal hypotension, premature separation of the placenta, a hypertonic uterus, and a prolapsed or nuchal cord. In these cases, the fetal pH can drop rapidly. The fetus brain relies heavily on energy from anaerobic metabolism once oxygen stores are depleted. This process is pH dependent, however, and the rate at which it proceeds drops significantly when the pH is less than 7. Other complications of fetal asphyxia include myocardial depression, a decreased responsiveness to catecholamines, a right shift in the fetal oxyhemoglobin curve, and an increase in pulmonary vascular resistance.

Compared to adult patients, you would expect a term neonate to exhibit

Term neonates exhibit decreased cardiovascular responsiveness to many drugs. The dose of dopamine required to increase blood pressure and urine output in neonates may be as high as 50 mcg/kg/min. This dose would produce such severe vasoconstriction in adults that it could cause injury to the patient. Infants (both preterm and term) have a higher proportion of water compared to their body mass. As a result, the volume of distribution for water-soluble drugs is greater. Because of this, they often require a higher loading dose of water-soluble drugs such as digoxin, succinylcholine, and some antibiotics. Children and adolescents have fat and muscle masses comparable to that of adults, but term and preterm neonates have a decreased proportion of both. Protein binding is decreased in preterm and term infants but is similar between children and adults.

Which of the following would be an acceptable intramuscular induction dose of ketamine in a 50 kg patient?

The IM induction dose of ketamine of 5-10 mg/kg. In this patient, the appropriate range would be between 250 mg and 500 mg.

What is the normal mean fetal heart rate range?

The baseline mean heart rate ranges between 110 and 160 beats per minute in the normal fetus.

The drug of choice for treating hypertension during anesthesia in a parturient with preeclampsia is

The first line drug for treating hypertension during anesthesia for preeclamptic patients is labetolol. Esmolol may also be used during induction. Large doses of opioids are avoided as they could produce maternal and fetal respiratory depression.

When does the foramen ovale typically close?

The foramen ovale typically closes within 1 hour of life as left atrial pressure exceeds right atrial pressure.

Select two reasons for low renal blood flow and glomerular filtration rate in utero.

The four principal causes for low renal blood flow and GFR in utero are low systemic arterial pressure, high renal vascular resistance, low permeability of the glomerular capillaries, and small size and number of glomeruli.

In the premature infant, you would expect the glottis to be at the level of

The glottis is at the level of C3 in the premature infant.

In the normal, full-term infant, you would expect the glottis to be at the level of

The glottis is at the level of C4 in the normal, full-term infant.

What would be an appropriate intravenous induction dose of propofol in a 7 year-old?

The induction dose of propofol in infants between 1-6 months of age is 3 mg/kg. For children 1-12 years old, it is 1.3-1.6 mg/kg.

Which of the following characteristics are consistent in a neonate with congenital diaphragmatic hernia?

The initial presentation of CDH is respiratory distress due to lung hypoplasia with tachycardia and tachypnea being present at birth. Compression of the vena cava by the intestines can also produce reduced preload and a corresponding decrease in cardiac ouput. The abdomen may appear scaphoid due to its contents being extruded into the thorax.

Which of the following would be an acceptable intravenous induction dose of ketamine in a healthy 35 kg pediatric patient?

The intravenous induction dose of ketamine is 1-3 mg/kg. In this patient, an acceptable range would be between 35 mg and 105 mg.

Which of the following changes occurs during pregnancy?

The left ventricular end-diastolic volume increases during pregnancy, but there is no change in the end-systolic volume. As a result, the ejection fraction during pregnancy is increased. Despite the increased blood volume levels, plasma renin levels are increased. The white blood cell count increases from around 6,000/mm3 to about 11,000/mm3 predominantly due to an increase in polymorphonuclear cells. The white blood cell count increases to 13,000/mm3 during labor and as high as 15,000/mm3 on the first postpartum day. Within a week postpartum, WBC levels fall to around 9,000/mm3.

Which local anesthetic would be least appropriate for use in an epidural for a patient undergoing a cesarean section?

The most common agents used for obstetric epidurals are 2% lidocaine with 5 mcg/mL of epinephrine and 3% chloroprocaine. Typically 15 to 25 mL of anesthetic administered in divided doses over 5-10 minutes will produce anesthesia adequate for the procedure. Bupivacaine is no longer used for obstetric epidurals because of the higher risk for local anesthetic systemic toxicity. Ropivacaine 0.5% can also be used as a substitute for bupivacaine as it has a lower risk for toxicity.

You administer an intramuscular dose of midazolam to a pediatric patient without an IV who cannot cooperate to take PO midazolam. What is the minimum amount of time should you wait before considering a supplemental dose?

The onset time of IM midazolam is 3-5 minutes and the time to peak effect is 10-20 minutes. You should wait at least 20 minutes before considering giving a supplemental dose of midazolam.

What is the appropriate dose of 0.3 M sodium citrate in mL for a 20 kg pediatric patient?

The pediatric dose of 0.3 M sodium citrate is 0.4 mL/kg. For this patient, the dose would be 8 mL.

Which of the following would be an appropriate dose of intranasal midazolam in a 20 kg pediatric patient?

The pediatric dose of intranasal midazolam is 0.1-0.2 mg/kg. For this patient, the range would be 2-4 mg.

Which epidural techniques would be effective in preserving motor function in a laboring parturient without compromising analgesia?

Using larger volumes of dilute local anesthetic or adding a lipid-soluble opioid to the local anesthetic are effective means of maintaining epidural analgesia for a parturient without increasing the risk for loss of motor function. Adding epinephrine is a technique used for prolonging the duration of an anesthetic. Parturients should not be placed supine for fear of aortocaval compression.

A patient is undergoing labor with an extremely preterm infant. Vaginal delivery is planned. What anesthetic/analgesic technique would be most advantageous in this instance?

When vaginal delivery of a preterm infant is planned, neuraxial anesthesia is advantageous because it produces relaxation of the pelvic musculature and helps reduce the risk of intracranial trauma in the fetus as it is being delivered.