OB Flashcards
(37 cards)
What are the classifications of the hypertensive disorders in pregnancy (toxemia of pregnancy; pregnancy induced hypertension)?
gestational hypertension
preeclampsia (1- preeclampsia without severe features, 2- severe preeclampsia/eclampsia)
chronic hypertension
chronic hypertension with superimposed preeclampsia
Define gestational diabetes
gestational hypertension, or pregnancy induced hypertension, is blood pressure of 140/90 and above in an otherwise healthy woman after the 19th week of gestation
Define eclampsia (preeclampsia with severe features)
Eclampsia is present if seizures or coma occur in the syndrome of pregnancy induced hypertension. Eclampsia is therefore defined as preeclampsia with severe features.
What are the risk factors for preeclampsia?
risk factors include: chronic renal disease, chronic hypertension, obesity, nulliparity, family history of preeclampsia, and advanced maternal age
What is the cause of preeclampsia?
Abnormal placental implantation. This abnormal placenta releases vasoactive substances causing dysfunction of the maternal vasculature
What is the drug of choice for seizure prophylaxis in a patient with preeclampsia? Why?
Magnesium sulfate is the drug of choice. It’s 50% more effective in preventing new onset and recurrent seizures than other commonly used anti convulsants.
The patient with preeclampsia is in danger of developing serious complications. Name eight serious complications.
1) pulmonary edema
2) airway obstruction
3) placental abruption
4) cerebral hemorrhage
5) cerebral edema
6) DIC
7) HELLP syndrome
8) renal failure
9) CHF
List medications used to blunt the hemodynamic response to laryngoscopy and intubation during induction of general anesthesia.
labetalol, esmolol, Nitroglycerin, sodium nitroprusside and remifentanil
why is hydralazine a commonly used antihypertensive in preeclampsia?
it’s a vasodilator that also increases uteroplacental flow and renal blood flow. nitroglycerin and labetalol are also commonly used
is regional anesthesia (epidural, spinal, CSE) contraindicated in preeclamptic patients?
provided there is no severe clotting deficit or plasma volume deficit, regional anesthesia can be safely used.
what three anesthetic considerations must be taken in the parturient receiving magnesium sulfate?
1) causes prolong duration and intensity of nondepolarizing muscle neuromuscular blockade
2) causes uterine vasodilation causing postpartum uterine atony and hemorrhage
3) interacts with calcium entry blocking agents
Once the fetus and placenta are delivered the mother is no longer at risk for complications of preeclampsia: true or false
false. pulmonary edema, stroke, embolism, airway obstruction, and seizures are a significant risk postpartum. severe preeclampsia, HELLP, and eclampsia can present for the first time in the postpartum period sometimes as late as four weeks after delivery
Which drugs commonly used in anesthesia readily cross the placenta?
Most drugs, including many anesthetics, readily cross the placenta. These include: atropine, scopolamine, beta blockers, nitroprusside, nitroglycerin, diazepam, midazolam, propofol, ketamine, etomidate, thiopental, halothane, isoflurane, desflurane, nitrous oxide, local anesthetics, opioids, and ephedrine.
Which medications used commonly during anesthesia do not cross the placenta and would need to be given directly into the fetal vein?
glycopyrrolate, heparin, depolarizing and nondepolarizing muscle relaxants, and phenylephrine do not cross the placenta and would need to be given directly into the fetal vein
What are the four key factors that influence the rate of drug diffusion to the fetus?
1) physiochemical characteristics of the drug
2) dose and mode of administration
3) placental maturation
4) hemodynamic events within the fetomaternal unit
Which is more lipophilic, the ionized or non ionized form of a drug?
non-ionized
What is the effect of intravenous 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
Magnesium sulfate is a commonly used drug in pregnancy. Name three advantageous effects of magnesium sulfate in pregnancy
tocolysis
anti-convulsant
fetal neuroprotective agent
Why is sodium bicarbonate routinely added to pre-packaged lidocaine with epinephrine for epidural anesthesia prior to cesarian section?
Alkalization of the local anesthetic hastens the onset of neural blockade and improves the quality of the block. Commercial preparations of local anesthetic, especially those containing epinephrine, are acidic. Adding sodium bicarbonate increases the amount of drug in the lipid soluble form thus increasing the rate of diffusion across lipid membranes. Sodium bicarb cannot be added to bupivacaine as it will precipitate
What is the impact of adding epinephrine to local anesthetics used for epidural anesthesia?
During cesarian section, adding vasoconstrictors such as epinephrine to a local anesthetic prolongs the duration of the block, increases the intensity of the block, and decreases systemic absorption
when is ketamine used for cesarian section? specify the 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 RSI of the parturient is 1 mg/kg. At higher doses, ketamine increases uterine tone and could endanger the fetus. Ketamine crosses the placenta due to its high lipid solubility. Ketamine at doses of 0.25-0.50 mg/kg IV produce rapid analgesia for labor and delivery. Ketamine given too close to delivery can cause respiratory depression and muscular hypertonicity resulting in lower apgar scores
Besides induction of labor, what else is oxytocin routinely used for an obstetric anesthesia?
Oxytocin is the first line treatment for uterine atony. Oxytocin stimulates uterine smooth muscle and is routinely given intravenously. Immediately after delivery, rapid doses can cause hypotension. Prolonged infusions can lead to hyponatremia, fluid retention, and neurologic dysfunction. In the non preeclamptic patient, an ergo alkaloid (methergine) is next line therapy followed by prostaglandins (hemabate).
Obese parturient’s are at increased risk for what 10 complications?
1) gestational hypertension
2) gestational diabetes
3) preeclampsia
4) infection
5) thromboembolism
6) stillbirth
7) fetal demise
8) difficult vaginal delivery
9) cesarian delivery
10) difficult airway
the fetus is at risk for macrosomia, shoulder dystocia, and congenital anomalies
What is the preferred method of pain relief for the obese parturient?
early placement of continuous neuraxial analgesia