Obstetrics: Part 1 Flashcards
Why is conflict of interest possible only in this patient population?
Maternal fetal interest can be contrary
By standard of our profession whose needs come first (mother or child)?
Mother
Define gravida
Number of times the patient has been pregnant
Define parity
Number of babies born to patient
Explain the number system for describing parity
First number: full-term births
Second number: preterm births
Third number: losses
Fourth number: living children
Define gestational age
How far along the fetus is in development
At what point in gestation is the fetus considered full-term?
38 weeks
What is effacement?
Description of how thick or thin the uterine walls are. (100% is really thin)
The cervical exam for the obstetric patient consists of what three components?
Dilation
Effacement
Fetal descent (station)
What EKG changes can be noted at term in the obstetric patient?
Left axis deviation due to displacement of diaphragm by uterus
Increased risk for arrhythmias
What is aortocaval compression?
Also known as supine hypotension syndrome
-Hypotension associated with pallor, sweating, or nausea and vomiting
20% of women
What is the most common cause of anesthesia related mortality in this population?
Loss of airway
What are some physiologic changes that affect the ecstatic patient’s airway status?
Capillary engorgement of the mucosa Increased risk of epistaxis Can continually worsen over hours Edema (esp with PIH) Difficulty positioning
What are some gastrointestinal changes seen in the obstetric patient?
Delayed emptying
Decreased pH
Incompetent gastroesophageal sphincter
How do the pregnant patients G.I. changes effect the anesthetic plan?
ALWAYS a full stomach
-given sodium citrate
If General, cuffed tube, RSI, premeds
What sort of hematologic changes are seen in pregnant women?
Increased total blood volume Dilutional anemia Decreased platelet count Increased coagulation factors Elevated D-dimer
Hypercoagulable
At what point during gestation is there a change in MAC requirements?
Decrease in MAC by 8-12 weeks
Historically and worldwide, what is the number one cause of Pregnancy related mortality?
Dr. Hall says Murder
Dr. Forkner says hemorrhage (I’d go with that)
In the United States, what is the number one cause of Pregnancy related mortality?
Cardiovascular disease
What are some possible explanations for the rising maternal mortality rate in the United States?
Rising numbers of the Cesarean sections
Rising number of patients with advanced maternal age and comorbidities
What is the safest and most effective medical intervention for labor pain?
Lumbar epidural
What are some things that tend to worsen labor pain?
OP Delivery (Occiput Posterior)-face up
Use of Oxytocin
Use of forceps
What are some alternative methods for pain relief during labor?
Hypnosis
Lamaze breathing
Acupuncture
Biofeedback
Why are intravenous opioids not the first choice for analgesia in the pregnant patient?
Higher risk for baby and mother
Not as effective as epidurals
The uterus and cervix are innervated from which levels?
T10-L1
Optimal analgesia for labor requires neural blockade at what levels in the first stage of labor? second stage?
1st Stage: T10 - L1
2nd Stage: T10 - S4
When does the spinal cord and 60% of patients?
L1
List some contraindication to neuraxial blockade
Patient refusal Coagulopathy Infection @ site Presence of foreign bodies Spinal cord pathologies Thrombocytopenia Untreated bacteremia or viremia Complete dilation of cervix, 2nd stage labor
What is given before or during placement of an epidural to help prevent hypotension?
Fluid bolus
What is an acceptable platelet count for administering an epidural?
70-100,000
Why is platelet count important to know before doing an epidural?
Low platelet count = Increased risk for epidural hematoma
What must be monitored when placing an epidural?
Blood pressure every five minutes
Pulse ox
How are the Spinal cord ligaments different in a pregnant patient?
Softer
Regional anesthesia for Cesarean section requires what sensory level blockade?
T4
What is a classic test dose for an epidural and what will it tell you?
3mL = Lidocaine 1.5% (45mg) w/ 1:200000 epi
-Will tell you if catheter is intrathecal or intravascular
A positive test dose when placing an epidural will present with what symptoms if it is intrathecal? Intravascular?
Intrathecal: Immediate spinal block, numbness, difficulty moving legs
Intravascular: Increased HR, ringing in ears, numbness and tingling around mouth, metallic taste
What is true of epidural dosing?
Always incremental
Usually 3 or 5 mL boluses
Will see pain reduced on patient’s face before patient endorses reduced pain
1st Stage labor pain is what kind of pain?
Visceral, not localized
The sensations of pain, touch, temperature and motor function are blocked in what order?
- Pain / temperature
- Touch
- Motor
What are the risks and benefits of combined spinal epidural (CSE)?
Benefits: near immediate pain relief, confirmation of epidural space
Risks: slight increase in risk of spinal headache, paresthesia possible
What is the risk of a subdural catheter?
Cannot be placed intentionally
Risk = Potential for arachnoid rupture and intrathecal exposure to epidural medication
List some possible risks of epidural placement
Inadvertent dural puncture Hypotension Failed block Intravascular or intrathecal injection Nerve injury Prolongation of 2nd stage labor Epidural hematoma Infection
What is the Ferguson reflex?
Urge to push
What is an inadvertent dural puncture?
“Wet tap”
-Epidural needle punctures the Dura and CSF comes through
What are the two options in the event of a wet tap?
A) Remove needle and place epidural at an adjacent level
B) Insert catheter into intrathecal space
What are the benefits and risks of a spinal catheter?
Benefits: no risk of further wet tap, reduced risk of headache, reliable, strong block
Risks: high spinal
What is the most common indication for a C-section?
Arrest of dilation
What are some indications for C-section
Arrested dilation Nonreassuring fetal heart rate Cephalopelvic disproportion Prior C-section Malpresentation Prior surgery involving the uterine corpus Arrest of descent
Uterine cord prolapse, placental abruption, placenta previa (rarer)
What is a normal fetal heart rate?
110 - 160 BPM
When monitoring fetal heart rate, the tracing is evaluated for what?
Decelerations (in relation to contractions)
Accelerations (related to fetal movement)
Variability (fine and coarse)
Early decelerations in fetal heart rate tracings are associated with what?
Head compression as fetus moves toward delivery
Very well decelerations can be associated with what?
Umbilical cord prolapse
Late decelerations are suggestive of what?
Fetal asphyxia following contractions, such that contractions are cutting off fetal blood supply
Why are fetal heart rate decelerations important?
One of the only measurable fetal responses to stress
What type of anesthetic is preferred for a C-section and why?
Neuraxial preferred
For General: Mortality rate 17x greater Increased pain Fetal transfer of induction drugs Risk of losing the mother's airway
What are some advantages and disadvantages of spinal anesthesia?
Advantages: better block, smaller needle, confirmation of placement
Disadvantages: procedure must finish before dose wears off, hypotension risk, not for MS patients
How can you create a denser epidural block?
Add narcotics
What is the first sign of hypotension?
Nausea and vomiting
What is the first drug given after the baby is born and the cord is clamped?
Pitocin (oxytocin)
20-40U in 1L bag
In the event of neonatal distress, what is the first priority?
The mother. Once she is stable the provider may assist with the neonate
Why is a stat C-section called?
Emergency C-section necessary to save life of the mother or fetus
What is the most important element of a stat C-section?
Time
Speed is Key
Is a stat C-section is performed under general anesthesia, what must be done to the patient prior to induction?
Prepped and draped so if induction goes badly fetus can be section and saved
What are some important considerations for general anesthesia for a stat C-section?
Always RSI
Limit opioids and volatile anesthetics until baby is out
Surgery starts when tube placement confirmed
At what point during a C-section do you consider redosing the epidural catheter?
1-1.5 hrs
If single shot spinal is wearing off, or there is a “hotspot” what other drug is often given to provide analgesia?
Ketamine
-be prepared for hallucinations
