OB Flashcards
1
Q
For OB patients, you want to make sure to have this type of cart
A
Difficult Airway
2
Q
When is there the greatest cardiac demand on parturients?
A
During and right after delivery.
3
Q
When are parturients at greatest risk for myocardial ischemia?
A
During and right after delivery, because this is the period of greatest cardiac demand
4
Q
A parturient is considered a full stomach after ____ weeks
A
12
5
Q
Why are pregnant women at risk for gallstones?
A
Everything in the GI tract slows down, causing stasis.
6
Q
A fetus is considered acidotic if pH is
A
7.2
7
Q
Fetal bradycardia is considered
A
HR < 110
8
Q
Normal variability for a fetal HR
A
5-25 bpm
9
Q
Normal fetal HR
A
120-160
10
Q
What can cause fetal bradycardia? Treatment?
A
Causes
- Maternal/fetal hypoxia
- uterine contractions
- vagal
- head compression
Treat with fluids, positioning, and oxygen.
11
Q
CO returns to normal ___ weeks post-partum
A
4 weeks
12
Q
HR will increase by ____,
CO increases by ____,
and SV increases by _____
A
HR 23-30%
CO by 30-50%
SV by 20-50%
13
Q
BP changes
A
- SVR decreases by 20%, but SBP is unchanged.
- This is probably due to the increase in CO and increase in blood volume.
- MAP however, decreases slightly.
14
Q
What can cause hypotension in parturients?
A
- Supine positioning
- Induction agents
- Sympathetic blockade from regional blocks
15
Q
Treatment of maternal hypotension
A
- Positioning
- fluids
- O2
- TED stockings
- Ephedrine &
- Phenylephrine
16
Q
Compression of IVC vs. aorta
A
- IVC compression causes a decrease in venous return, CO, and thus causes hypotension.
- Aortic compression is usually not associated with s/s, but does decrease uteroplacental perfusion
17
Q
Plasma volume increases by __%, but RBC volume only increases by ___
A
50%
30%
18
Q
Coagulation in parturients
A
- Clotting factors increase (in preparation of delivery).
- Platelets remain the same or decrease slightly.
19
Q
Plasma cholinesterases in parturients (increase/decrease)
A
Decrease.
Will/may have prolonged duration of sux!
20
Q
EBL for vaginal delivery
A
500cc
21
Q
EBL for c-section
A
500-700
500 with regional anesthesia
700 with general anesthesia
22
Q
Regional anesthesia is not advised if plt counts are below
A
70,000
23
Q
When should you suspect a PE?
A
Parturients are at risk for PE because they have increased coagulation factors; PE should be suspected if mother has:
- SOB, chest pain, coughing up blood, arrhythmias, pain or tenderness in legs.
- We want mothers to ambulate early and wear compression stocking!!
24
Q
Respiratory changes in parturients
A
- Decrease in FRC (20%)
- Small airways close faster (closing capacity)
- Increased WOB
- O2 demand increases by 30%
- Increase in TV by 50%
- RR also increases
25
The dissociation curve will shift to the
right
26
Effects of progesterone on respirations
1. Tells resp center to increase respirations
2. **Sensitizes the resp center to CO2**
* *increases* **MV** to drive maternal PaCO2 to **30-32**,
* causes a **compensated respiratory alkalosis** with excretion of bicarb
3. Chest muscle relaxation, allowing the chest wall to expand more easily
27
ABG of pregnant women
* Remember that they have increased sensitivity to CO2 d/t progesterone, so they have an increased MV.
* This results in a **compensated respiratory alkalosis**
* ****normal **pH** (compensated)
* low **pCO2** (hyperventilations)
* low **bicarb** (excreated by kidneys)
28
Why is it important for parturients to have **oxygen**?
* Increased oxygen **consumption**
* decreased **FRC**
* decreased **CO** when supine
29
Why is hypoventilation in parturients so bad?
1. It decreases O2 availability to fetus
2. Also, mothers can quickly develop acidosis
* causing BVs to constrict and decreasing uteroplacental flow
30
Will IAs have a faster or slower effect on parturients?
**Faster** d/t increase in MV
31
Choice of ETT size in parturients
**6.0-7.0**
Generall err on the smaller side,
because they may have edematous airways
32
Clinical implication of full stomach past 12 weeks rule
* Bicitra given to all laboring women
* Reglan H2 Antagonists (Ranitidine, Famotidine)
33
GI changes in pregnancy
* Increased gastric acidity
* peristalsis is slowed,
* decreased lower esophageal spincter tone
* stomach displaced upward and 45 degrees to the right
* Labor pains and opioids delay gastric emptying and promote emesis
34
CNS changes in pregnancy
* Increase in endorphine
* higher pain threshold
* Increased sensitivity to IAs, LAs, and opioids
35
MAC requirements decrease by \_\_\_% in parturients
**40%**
36
Renal Changes in pregnancy
1. Increase in **RBF** and **GFR** d/t increased CO
2. Because of this, **lower** serum **BUN/Cr** values
37
Formula for Uterine Blood Flow
_(Uterine **arterial** BP - Uterine **Venous** BP)_
(Uterine **vascular** resistance)
38
Normal uterine blood flow at term
**500-700** cc/min
39
Why is maternal hypotension such a big deal?
* The uterine vascular bed **lacks autoregulation**!!!!
* Maternal **UBF** is dependent on **BP** and **CO**
40
Factors that *increase* uterine vascular resistance, and thus *decrease* UBF
1. Oxytocin
2. contractions
3. ketamine
4. abruptio placentae
5. severe HTN
41
Drug transfer across the placenta depends on
1. MW
2. Size
3. Lipid Solubility
4. Maternal drug concentration
5. Maternal and fetal pH (more non-onized means more transfer)
6. Low protein binding
42
What is the single best non-invasive indicator of fetal well-being??? \*\*\*\*
Fetal HR variability
Should be between **5-25**bpm
43
Causes of fetal tachycardia
1. Chronic fetal distress
2. Maternal Fever
3. Certain medications (epi, ephedrine, atropine, etc)
44
Fetal bradycardia is a FHR
**HR \< 110**
45
Causes of loss of variability
1. CNS depression that may be due to:
1. asphyxia, general anesthetics, neurologic abnormalities or from maternal opioids
46
Early decels
Develop **with** uterine contraction.
1. **Head compression** from contraction causing **increased vagal tone**.
2. These decels are **transient** and **well tolerated** by the fetus.
47
Late decels
Begin **AFTER** onset of uterine contraction.
1. May be caused by CNS ischemia, myocardial ischemia or fetal hypoxia.
2. This is an **ominous** sign!!
3. Maternal **hypotension** must be treated.
48
Variable Decels
Variable in shape and timing, short in duration, and occurs within 30 seconds of onset.
1. Caused by **cord compression**, which activates the **carotid baroreceptor reflex**.
2. If the compressions are frequent or prolonged, it could result in fetal asphyxia.
3. Most common pattern observed in the intrapartum period.
49
Intrauterine resuscitation
1. Supplemental oxygen
2. LUD or knee-to-chest positioning
3. Rapid fluid infusion
4. Check maternal vital signs, and treat hypotension with pressors
5. Stop oxytocin if it was being given, and begin tocolysis with terbutaline or NTG
6. Assess level of blockade for spinal/epidural
7. Amnioinfusion
* inserting fluid in the uterine cavity to decrease cord compression
8. C-section
50
Opioids in the laboring woman
Commonly given, although data suggests they provide limited analgesia.
* **_Meperidine_** (Demerol) **25-50**mg
* most common
* metabolite normeperidine can linger in the fetal circulation and cause depression and will lose variability.
* **Opioids also have unwanted side effects**
* N/V, resp depression, sedation, **orthostatic** hypotension, and **neonatal depression.**
* **PCAs** of fentanyl or remifentanil may be used.
* Agonist/antagonists (**butorphenol** and **nalbuphine**)
* decreased N/V and "ceiling effect" of respiratory depression.
* Nalbuphine (Nubain) has less dysphoria than butorphenol.
51
Gases for laboring pain
**Entonox** - 50/50 mix of nitrous and O2
## Footnote
**Sevoflurane**
52
Stages of Labor and Blocks Needed
1. 1st = Beginning of painful contractions to full dilation -
* **Longest** Stage
* Mostly **visceral** pain
* **T10-L1** innervation
2. 2nd = Complete dilation to delivery
1. Most painful stage (**somatic** pain)
2. **L2-S4** innervation
3. 3rd = From delivery of baby to delivery of placenta
53
Midazolam in laboring women
* Low doses **0.5-1**mg to provide anxiolysis
* but make sure they remember the delivery
54
Epidural catheter is inserted __ - \_\_cm into epidural space for parturients
**4-6 cm**
Normal population = 2-3cm
55
LA of choice for emergency c-section
**Chloroprocaine** (d/t highly rapid onset)
56
Rules for epidurals
1. Parturient should be at least **4 cm** dilated
2. Test dose **between** contractions
3. Fluid load with **500 cc** crystalloids before induction
57
CSE is great option for women, but carries increased risk of...
CSE = combined spinal and epidural
non-reassuring FHR patterns and fetal bradycardia
58
Treatment for **Post Dural Puncture Headache**
1. Bedrest
2. Caffeine
3. Hydration
4. OTC analgesics
5. Epidural blood patch
59
Most common reasons for having a c-section
1. Previous c-section
2. Cephalopelvic Disproportion (CPD)
3. Failure to progress
4. Malpresentation
5. Prematurity
6. Non-reassuring fetal status
60
This is the preferred muscle relaxant for c-section under general anesthesia
1. **Sux** (guessing d/t short duration) and need for RSI If can't use sux, rocuronium is a suitable alternative.
2. Do **not** give **defasiculating** dose of roc (they have increased sensitivity
61
Induction agent of choice if the mother is having a **hypotensive** crisis
Ketamine **1-1.5** mg/kg
62
Time between incision of the uterus and delivery of the fetus MUST be less than ___ minutes
32
63
Optimal dose of bupivacaine for spinals for C/S
**12** mg Provides block for **1.5-2** hours
64
Need this levels spinal block for C/S
T4
65
How to prevent hypotension with spinal blockade
**2L** crystalloid
**LUD**
Pressors
66
What is the first line pressor for parturients?
Ephedrine
67
Top causes of maternal death related to anesthesia
#1 Airway problems #2 LA toxicity
68
PIH definition
Pregnancy Induced HTN BP \> 140-90 or BP \> 30 points SBP from baseline or \>15 points DBP from baseline Severe HTN in 160/110
69
PIH can cause
Cerebral hemorrhage, abruptio placentae, liver and renal failure, DIC
70
Risk factors for PIH
Primiparity Multiple gestation Chronic HTN African Americans Chronic Renal Disease Obesity Diabetes Family history of pre-eclampsia These should all make logical sense
71
What is preeclampsia?
A hypertensive disorder. New onset of HTN that develops after 20 weeks gestation, along with proteinuria. HTN without proteinuria is just PIH.
72
Symptoms associated with preeclampsia, and other disorders it can lead to
1. Associated with vasoconstriction (causes HTN)
2. edema (proteinuria)
3. hypovolemia,
4. coagulation abnormalities and poor organ perfusion
5. Can lead to cerebral bleeds
6. pulmonary edema
* (dilutional hypovolemia decreases oncotic pressure and also increased pulmonary cappilary perneability)
7. hepatic rupture
8. and HELLP syndrome.
9. May experience epigastric pain if there is liver involvement.
73
Mild vs. severe preeclampsia
Mild = BP \> **140-90** or BP **\> 30** points SBP from baseline or **\>15** points DBP from baseline
* **Proteinuria** \> **500mg**/day
SEVERE = BP \> **160/110**
* Proteinuria \> **5g**/day
* CNS changes, blurred vision
* Hepatic involvement/epigastric pain
* Pulmonary edema
74
What is eclampsia?
Defined as preeclampsia with **seizures**. This is a life threatening emergency
75
Treatment of pre-ecclampsia and ecclampsia
_Pre-ecclampsia_
* Goal = DBP \< 110
* Labetolol, hydralazine (may also use NTG or nefedipine)
_Ecclampsia_
* **magnesium sulfate** (bolus **4g** over 10 minutes then **1**g/hour)
* LUD, fluids, oxygen antihypertensives, coag studies May need immediate fetal delivery
76
Goal of treatment of preeclampsia
* Control HTN
* prevent seizures
* Correct coagulation issues
* delivery of the fetus (the only definitive treatment)
(want to gradually decrease the HTN to avoid fetal distress could
77
Why is Magnesium Sulfate used?
What are its effects?
* Drug of choice for **hyperreflexia**, and **prevention/control** of **seizures** related to preeclampsia and eclampsia
* Effects:
* **Relaxation** of vascular, bronchial, and uterine smooth muscle\*\* (**HYPOTENSION**)
* Mild sedative
* Potentiates NDMRs
* Crosses the placenta (causes neonatal hypotonia and resp depression)
78
Dose of Mag Sulfate therapy
Bolus **4g** over **10 min**
Then maintenance of **1 g/hr**
79
Mag Sulfate effects can be reversed with
Calcium Calcium Gluconate **1g**
Calcium Chloride **300mg**
80
Paralytic of choice for those on Mag Sulfate therapy
* Sux **1mg/kg**
* **NEVER** give defasciculating dose prior
* MGSO4 will **POTENTIATE** all **NMBs**, and
* give **1/3** to **1/2** of the normal maintenance dose
81
Effect of Pressors for those on mag therapy
* **Decreases** the response of alpha agonists
* neo and ephedrine won't work as well
* But ephedrine is preferred to neo
82
What is HELLP syndrome?
Severe form of preeclampsia characterized by:
* **H**emolytic anemia
* **E**levated **L**iver enzymes
* **L**ow **P**latelet counts
(Can be mild or be so severe that it causes multiorgan failure)
83
S/S of **HELLP** syndrome
Hallmark sign is **hemolytic anemia**!!
* Epigastric pain = most common initial symptom (90%)
* Malaise (90%)
* N/V (50%)
84
Risks of vaginal birth after cesarean
1. **1% chance uterine rupture**--\> emergency for both mother and fetus
2. Uterine infections
3. May need blood transfusion
4. Risk of an emergency c-section
85
How to relax the uterus
Sevoflurane
Nitroglycerin **50-100**mcg
86
Multiple gestations is associated with
1. Abnormal fetal positions
2. PIH
3. Premature labor
4. Increased risk of potpartum hemorrhage d/t uterine atony
5. Higher anesthesia morbidity (more aortocaval compression, even lower FRC, high risk for spinals and epidurals)
87
Definition of preterm labor
1. Regular uterine contractions that occur between 20-37 weeks of age.
2. This is the leading cause of perinatal morbidity and mortality\*\*\*
3. Fetus at high risk for resp issues and intracraniall hemorrhage (d/t soft intracranial vault)
88
Treatment for premature labor
1. Bedrest FHR monitoring
2. Check for Premature Rupture of memebranes
* Tocolytic agents
* CCBs (nifedipine)
* NSAIDs (indomethacin and ketorolac)
* B2 agonists (Terbutaline)
* Mag sulfate
* Steroids for surfactant production
89
Affects of NSAIDs on the fetus
* Constriction of ductus arteriosus
* pulmonary HTN
* renal dysfunction
* intraventricular hemorrhage
90
EBL for C/S with hysterectomy
1500cc
91
Treatment of postpartum hemorrhage
1. Volume replacement
* more concerned with fluid than necessarily giving blood
2. Blood
* give type-specific but uncrossmatched if an emergency
3. Drugs
1. Oxytocin
2. Ergot alkaloids (methergin & ergocitrate)
3. Prostaglandins
4. Embolization of uterine/ovarian arteries
5. Hysterectomy
92
Placenta previa is characterized by
Painless, bright red, vaginal bleeding
93
Anesthesia management for placenta previa
* Prepare for high **blood loss**
* Aggressive **fluids** (may need central line)
* **Foley**
* May need **a-line**
* Large bore **IVs**
* Be ready in the OR for **either** regional or GA.
* Have **both** set up and ready to go!
* Do regional if ***stable***
* If ***unstable***, do GETA with RSI using **ketamine** or **etomidate**
94
Characteristics of abruptio placentae
* Painful, dark, clotted, vaginal bleeding
* Bleeding may be underestimated because blood may be concealed behind the placenta
* Maternal mortality high (2-11%), and fetal mortality is even higher (50%).
95
What is placenta accreta?
Abnormally adherent placenta to the uterus
* Placenta vera- **adhered** to the myometrium with invasion of the uterine muscle
* Placenta increta- invasion **into** the myometrium
* Placenta percreta- invasion **through** the myometrium, and into the surrounding structures of the uterine serosa and pelvis
96
First sign of **uterine inversion**
* **Hypotension**!
* There is blood loss, but the fundus of the uterus is blocking it's exit through the vajay.
* Therefore, the first thing you will see is hypotension.
97
Dose of **NTG** for uterine relaxation
**1** mcg/kg
Usually **50-200** mcg
98
Amniotic Fluid Embolism
1. Acts as an **embolus** and get can lodged in places
2. Body recognizes it as **foreign**, resulting in an **anaphylactic/anaphylactoid** reaction
* Clinically looks like **PE + anaphylaxis**
* 60-80% mortality rate!
99
In morbidly obese patients, LA volume should be (increased/decreased)
**Decreased**
| (less space in the epidural space)
100
If a parturient requires non-OB surgery, this is the most vulnerable time for them to have it
* 3-8 weeks gestation, because there is lots of growth and development occurring.
* Regional is always best option!
* Minimizes exposure to systemic anesthetic medications
101
Parturients often present for these **non-OB** surgeries
Cholecystectomies and appendectomies
102
Avoid these **known teratogens** especially in the first semester
**N2O** and **benzos**
benzos linked to cleft lip/palate
103
FHR monitoring isn't needed if fetus is less than ___ weeks
**20**
(no chance of viability even if emergency occurs)
