Ex1 OB 2 Part 2 Flashcards
1
Q
Most common type of C/S
A
Low transverse incision
2
Q
Types of C/S incisions
A
- low transverse (lower uterine part, horizontally)
- low vertical
- Classical incision (middle, vertical)
3
Q
Pfannenstiel incision
A
Low transverse incision
most common C/S
4
Q
Why did they stop the classical incision?
A
increased risk of uterine rupture in subsequent pregnancies/labor.
5
Q
Most common indications for C/S
A
- failure of labor to progress
- fetal distress
- cephalo-pelvic disproportion
- prior uterine surgery or C/S
6
Q
Advantages of regional over GETA
A
- Lower maternal mortality rates
- Can be used in fetal distress w/o facing difficult intubation + further fetal compromise
- patient awake, less aspiration risk
- Less exposure of fetus to depressant drugs
7
Q
Disadvantages of regional vs GETA
A
- Accidental intravascular injection (possibility of convulsions, CV collapse, aspiration)
- Total spinal (severe HOTN, unconsciousness, aspirations)
- Risk of dural puncture H/A
8
Q
Advantages of spinal anesthesia
A
- Simplicity of technique
- Speed of induction (vs epidural)
- Reliability
- Minimal exposure of fetus to Rx
- Minimization of hazards of aspiration
9
Q
Disadvantages of spinal anesthesia
A
- High incidence of HOTN
- Intrapartum N/V
- Possibility of H/A after dural puncture
- Limited DOA (unless a continuous technique is utilized)
10
Q
spinal anesthesia C/I
A
- Severe maternal bleeding
- Severe maternal HOTN
- Coagulation disorders
- Some forms of neurological disorders (ex. MS)
- Patient refusal
- Sepsis (area of needle insertion or generalized)
11
Q
C/S Preop considerations
A
- Use of aspiration precautions recommended d/t pregnancy-induced GI changes:
- Metoclopramide 10 mg + an H2 blocker (famotidine 20 mg) IV can be used
- Nonparticulate antacid (bicitra 30-60 mL) depends on practice - Volume Loading (LR)
- T&S (unless emergent)
12
Q
Vaginal birth EBL
A
300-500mL
13
Q
C/S EBL
A
800-1,000mL
14
Q
Volume loading for C/S
A
~1L; doesn’t matter how fast
- reduces incidence of HOTN
- no difference in acid/base status, ephedrine use
15
Q
Spinal for C/S - drug + dose?
A
Hyperbaric Bupivicaine 0.75% 6-15mg
depending on location: 1.4-1.6mL
16
Q
Bupivacaine 0.75% administering 1.4mL … how many mg is this?
A
1 mL = 7.5 mg
.4mL = 3mg
1.4mL = 10.5mg
17
Q
Hyperbaric bupivacaine administration is associated with
A
Higher doses = greater reduction in MAP
18
Q
1.6mL Hyperbaric bupivacaine 0.75% attains what level?
A
T4 - Nipple line
19
Q
1.6mL Hyperbaric bupivacaine 0.75% lasts how long?
A
1.5-2 hours
20
Q
C/S Local anesthetic protocol
A
- Hyperbaric bupivicaine 0.75% 1.6 mL
- Fentanyl 10-20 mcg
- Morphine 0.1-0.25 mg
21
Q
C/S Local anesthetic protocol - fentanyl
A
10-20mcg (in TB syringe)
- decrease visceral discomfort
- may lower incidence of N/V during uterine manipulation
- 15mcg=adequate analgesia, significantly less N/V than 20 mg (research)
22
Q
C/S Local anesthetic protocol - morphine
A
- Duramorph = preservative free
0. 1-0.25 mg (in TB syringe) - for postop analgesia from 18-24 hours post op
23
Q
Why must preservative free analgesics be used intrathecally?
A
To avoid neurotoxicity
24
Q
If intrathecal morphine is used, what should be implemented?
A
- *duramorph
- postop monitoring protocol to monitor for respiratory depression (1:1000) + pruritis
25
Tx for pruritis
Benadryl (postop d/t morphine)
26
Other LAs used for C/S
1. Tetracaine 0.5% in 5% dextrose (lasts 90-120min), in practice up to 8h
2. Bupi 0.5% in 8% dextrose (90-120m), off label use, sensory density less than hyperbaric
27
C/S Intraop considerations: prior to placing spinal what should be done?
IV x 1 (18g), Monitors, O2 (possibly C/I d/t masking of high spinal), position: R lateral or sitting
28
After placement of a spinal, what must be done?
Lay mom down + place in L uterine displacement until delivery of infant
29
Tx: HOTN d/t spinal
Ephedrine 5-10mg
+/or
Phenylephrine 50-100mcg IV
30
Tx: HOTN + bradycardia d/t spinal
*sympathectomy
Tx: atropine 0.4mg PRN
--> or reverse trendelenberg
31
Definition: maternal HOTN
Decrease in SBP < 100 mmHg
or
Decrease > 30 mmHg from preanesthetic value
**depends on moms baseline
32
Incidence of maternal HOTN
80%
33
Higher the sympathetic block, the greater the risk of ______
HOTN + emesis (> T4)
34
Incidence of HOTN from spinal (prior to C/S) is less if ______ because _____
- mom has been in active labor
- Autotransfusion (500 mL+) d/t uterine contractions
- decrease in size of uterus d/t loss of amniotic fluid if membranes have ruptured
- Higher maternal catecholamines in labor
35
warning signs of maternal HOTN d/t spinal
lightheadedness, nausea, difficulty breathing, and diaphoresis
*SET BP to 1-2.5 minutes!
36
DOC maternal HOTN
Ephedrine (or phenylephrine)
37
MOA Ephedrine
stimulates both alpha + beta adrenergic receptors, cardiac stimulation + subsequent increase in peripheral/uterine blood flow
38
Ephedrine - disadvantages
crosses placenta + increases fetal heart rate + heart rate variability
39
Given 10mg/mL vial phenylephrine .... how to draw up/administer?
Draw up vial, inject into 100mL saline, draw 10 mL from bag
| =100mcg/mL
40
Disadvantage of using Phenylephrine
Profound bradycardia
41
Tx of phenylephrine induced bradycardia
Atropine or glycopyrrolate (0.1 rather than 0.2)
42
Which one is better for maternal HOTN: phenyl or ephedrine?
Depends on moms HR:
| give ephedrine if large dose of phenyl drops HR
43
When do we administer a test dose during neuraxial anesthesia?
During epidural placement - to confirm correct placement (NOT INTRAVASCULAR)
(Any ringing in ear? Funny taste in mouth?)
44
Complications specific to epidural anesthesia
1. PDPH
2. unintentional intravascular injection
3. shivering
45
Peak onset of shivering after epidural
10 minutes
46
MOA + Tx: shivering after epidural
vasodilation to BLE --> upper body compensates
| Tx: full lower bair hugger
47
Epidural anesthesia: Local anesthetics used
1. Chloroprocaine 3%
2. Lido 2% + Epi 1:200,000
3. Bupi/Ropi 0.5%
48
When is Bupi/Ropi used in epidural?
Labor epidural d/t greater ratio of sensory:motor blockade
49
When is Lido/Chloropr. used for epidural?
C/S d/t greater motor blockade
50
Stat C/S: which LA in epidural?
Chloroprocaine
51
Duration of surgical anesthesia: Chloroprocaine
30-40 min
52
Duration of surgical anesthesia: Lidocaine 2% with Epi 1:200,000
75-90 min
53
Duration of surgical anesthesia: Bupivicaine 0.5%
75-90 min
54
DOC OB Epidural
Lido 2% + Epi 1:200,000
55
ideal local anesthetic in the presence of fetal distress d/t rapid onset, short maternal half-life and fetal plasma half-life
chloroprocaine 3%
56
Chloroprocaine average onset of action
6-12 minutes
- up to 10 minutes for 2-choloroprocaine to attain a T4 level in a newly placed epidural
- to go from a T10 level with sensory blockade appropriate for labor analgesia up to a T4 block for surgical anesthesia can be obtained in approximately 5 minutes
57
Why isn't Chloroprocaine used more often?
- antagonizes mu-agonist narcotics (fentanyl, morphine) in epidural
- may interfere w/ subsequent epidural bupi
58
Epidural of choice in emergency C/S
Chloroprocaine 3%
59
Bupivicaine advantages + disadvantages in epidural
- slower onset
- lesser degree of HOTN
- only available in .5% and below
60
What can speed the onset of action + spread block of epidural?
- 1 mL Sodium Bicarb (7.5 or 8.4%) per 10mL LA
* * with Lido
* * NOT with Bupi
61
Administration of epidural
1. Confirm negative test dose
2. 15-20mL LA administered slowly in 5mL increments (wait 5 min, monitor BP, inject another 5mL)
3. Verification of catheter placement by aspiration is done with each new injection
4. Injection completed when T4 level achieved
62
Mom is on OR table, prior to C/S, LA injection is not working via epidural. What next?
Possible that
- epidural catheter migrated
- epidural not bathing all nerves ("hot spot")
63
Best option when Epidural is not working + mom has "hot spot" in middle of C/S
Kiss of ketamine: 10-20 mg
| or 30% N2O
64
After delivery via C/S, mom is in severe pain, what is another option?
IV narcotics PRN
or
Fentanyl 100 mcg diluted into 10mL saline via epidural
65
Anticipation of post-op C/S pain: Tx (dose, DOA)
Preservative free morphine via epidural, 3-5mg
| *lasts 12-24h
66
In addition to epidural morphine, post operative pain can be managed by _________
- patient-controlled epidural anesthesia (PCEA) with LA of low concentration +/or epidural narcotics
- ketorolac (Toradol)
67
NSAIDs - pain management post-op
* *no NSAIDs before baby is out
- verify with surgical team this is okay
- 30mg IM (or IV)
68
Why no NSAIDs before baby is out?
- suppresses uterine contractions
| - promotes closure of fetal PDA
69
Failed epidural rate
12% ("high")
70
s/s failed epidural
High # of top offs
71
Management of failed epidural
```
Management with RACE:
Recognize the problem
Assess the fetal heart rate
Consider the options
Evaluate the airway
```
72
Failure of epidural during labor: Tx
Replace epidural.
| Sit mom up, go to different space, place epidural.
73
Failure of epidural during C/S: Tx
*Reason for C/S: baby stable or unstable?
Unstable: no time to replace epidural/spinal -- GETA
Stable: time to evaluate next plan (replace epidural, spinal, etc.)
74
Failed epidural: General Options
- replace catheter if not urgent procedure
| - remove + perform spinal
75
Failed epidural: Replace with Spinal
* if dose of epidural was < 10mL can use normal intrathecal dose
- *hyperbaric*
- Leave sitting 1 – 2 min (control level of block)
76
Failed epidural: do not give spinal if
- bolus given in last 30 min
- pt weighs > 120 kg
- height < 4’ 10”
77
CSEs are most commonly used for
-repeat C sections or for patients who have had previous abd surgery (prolonging surgical time)
78
what MUST occur prior to induction?
- surgical team + patient prepped + draped, ready to start w/ scalpel in hand
* regardless of emergency vs. planned
79
Non-emergent + emergent preoxygenation
emergent: 4 VC breaths
| non-emergent: 100% O2 for 3 minutes
80
Induction agents
```
Thiopental
Propofol
Etomidate
Ketamine
Succinylcholine
```
81
Induction agents that cross placenta
thiopental, propofol
| both lipid soluble
82
Induction agent: Thiopental
4mg/kg
83
Induction agent: Propofol
2-2.5mg/kg
84
Induction agent: Etomidate
.3mg/kg
85
Induction agent: Ketamine
1-2mg/kg
86
Induction agent: Succinylcholine
1-1.5mg/kg
87
Induction agent: mom bleeding or hypovolemic
Reduce doses or use etomidate/ketamine
88
Maintenance Drugs
Until delivery: mix of 50% N2O/O2 + Sevo/Iso @ 75% MAC
- judicious use of NDMR after Sux wears off
- avoid hyperventilation (AE on UBF)
89
What does hyperventilation cause?
Hypocarbia
90
What does hypocarbia do to the placenta?
Decreases UBF (uterine blood flow)
91
What inhalational agents cross the placenta?
Volatiles + Nitrous
| -lipid soluble + have LMW
92
What NMBA cross the placenta?
Poorly lipid soluble + highly ionized - cross very slowly but pose no problems to fetus
93
Recall during C/S
Maternal awareness: 17-35%
| *high*
94
Maintenance: Oxytocin
10 – 30 units/L
added to IV infusion + administered after delivery of placenta to *stimulate uterine contraction*
AE: vascular relaxation (rapid infusions after C/S can cause HOTN)
-needs to be diluted
-Can double dose if needed.
95
Maintenance: Methergine
0.2 mg IM
or Hemabate 0.25 mg IM
may be given for uterine atony and/or increased bleeding
96
Once baby is delivered, what should be done?
Decrease VA to 0.5 MAC
| higher doses = decreased uterine tone = bleeding
97
Once cord is clamped, what may be done?
Balanced technique: N2O, narcotic + relaxant
98
Antibiotics for C/S
- Surgeon preference
- normally 2g Ancef
* given before incision
99
Timing of delivery
Neonatal status with C/S delivery under GA investigated using 2 time intervals:
1. Induction to delivery time (I – D)
2. Uterine incision to delivery time (U – D)
100
2 time intervals
1. Induction to delivery time (I – D)
| 2. Uterine incision to delivery time (U – D)
101
I-D
Induction to delivery time
102
U-D
Uterine incision to delivery time
103
I-D outcomes
better outcomes when:
| I-D time < 20 minutes
104
U-D outcomes
Uterine incision – delivery intervals > 180 seconds associated with low Apgar scores + acidotic babies
Increased U – D intervals also result in elevated fetal umbilical artery norepinephrine levels which may be a sign of fetal hypoxia
105
Adverse outcomes with prolonged U – D intervals may be the result of:
- The effect of uterine manipulation on uteroplacental + umbilical blood flow
- Pressure on uterus with accentuated aortocaval compression
- Compression of fetal head during difficult extraction
- Inhalation of amniotic fluid d/t gasping respirations by fetus in utero
106
Uterine Incision-Delivery Time Prolonged d/t tightened uterine muscle
Low dose nitroglycerin to relax muscle temporarily
1-2 mL of 100 mcg/mL Nitroglycerin
**only if OB wants**
107
C/S with GETA - no spinal/epidural/CSE
Anticipate postop pain
| **administer analgesics during emergence
108
C/S GETA emergence
- NDMR reversal if used
- Anticipation of postop pain (admin analgesics)
- Ondansetron 4 mg IV for N/V prophylaxis
- Extubate when pt wide awake
109
What drugs cross the placenta?
```
Induction agents
Inhalation agents
Neuromuscular blocking agents
Opioids (all)
Local anesthetics
Anticholinergics
Neostigmine
Benzodiazepines
Vasoactive drugs
```
110
Drugs crossing placenta: Local Anesthetics
- LAs have to be absorbed in systemic circulation before can be transferred across placenta.
- BUPIV + ROPIV are highly lipid soluble + can transfer with simple diffusion
- LIDO is less lipid soluble but has a lower degree of protein binding, so it will also cross placenta
111
Drugs crossing placenta: anticholinergics
- Glycopyrrolate is fully ionized + therefore poorly transferred across placenta
- Atropine demonstrates complete placental transfer
112
Drugs crossing placenta: Neostigmine
- Neostigmine = a small molecule able to cross placenta more rapidly than glycopyrrolate
- In a few cases where neostigmine used with glyco to reverse NDMB in pregnancy, profound fetal bradycardia reported
* SO, for GA in pregnancy where baby is to remain in utero, advisable to use neostigmine with atropine rather than glycopyrrolate
113
Drugs crossing placenta: Benzos
Benzos = highly lipid soluble + un-ionized
| = complete transfer
114
Non-OB surgery
1-2% of women undergo non-OB surgery during pregnancy
Most common procedure during 1st trimester = laparoscopy
Most common open abd procedure in pregnancy = appendectomy + cholecystectomy
115
Pregnancy + elective surgery
* avoid surgery during period of organogenesis during 1st trimester
* all elective procedures postponed until after delivery
116
Pregnancy + non-elective surgery
non-elective procedures should be performed in 2nd trimester if feasible
117
Fetal safety: teratogenic agents
- No agent proven to be teratogenic in humans
- nitrous oxide + diazepam in animal models = aroused concern, now questioned
Now we avoid N2O + all benzos
118
Non-OB cases: planning
-consult OB for all but the most minor surgical cases
**use regional techniques (esp spinal) when able!
- Continuous FHR monitoring may be indicated depending on operative site + fetal gestation
- A uterine tocodynamometer should be used to detect preterm labor (especially in posto)
119
If a pregnant pt is having a non-obstetric surgery and needed paralysis, how do you reverse?
Atropine rather than Glyco
adjunct to neuromuscular blockade reversal:
25–30 mcg/kg 30–60s before neostigmine
120
Atropine dosage when used in reversal with Neostigmine
25–30 mcg/kg 30–60s before neostigmine
| dose is approx half of neostigmine (atropine 20 µg/kg for neostigmine 40 µg/kg)
121
FHR monitoring - non-OB surgery
- After 18 weeks gestation, FHR monitoring is practical
| - After 25 weeks gestation, FHR variability is a reliable sign of fetal wellbeing
122
Cervical cerclage
Shirodkar + McDonald cerclages performed for cervical incompetence
- transvaginally during 1st/2nd trimester, prophylactically or emergently
- sutures removed @ 38 weeks
- no anesthesia req'd
123
Cervical cerclage: prophylaxis
12-14 weeks
124
Cervical cerclage: technique
- Spinal anesthesia is technique of choice, although an epidural may also be performed
- Avoid sedation or intrathecal adjuncts if possible d/t effect on fetus
- Avoid nitrous oxide + midazolam
125
cervical cerclage: spinal technique
Less medication, pt sits up for "dense saddle block", do not need T4 coverage
1-1.2mL Hyperbaric 0.75% Bupi
126
Postpartum Tubal Ligation
- Usually done 8h after vaginal birth if no complications
| - Surgeons make small sub-umbilical incision d/t fundus being at level of umbilicus
127
Postpartum tubal ligation: anesthetic considerations
- Delayed gastric emptying persists during early postpartum
- Bicitra, metoclopramide, famotidine given preop
- Easiest to use labor epidural (Keep in mind LA doses decreased with pregnancy)
- Otherwise, spinal most commonly done
- Ensure pt NPO between delivery + surgical procedure
128
VBAC
Vaginal birth after cesarean
| -TOLAC: trial of labor after cesarean delivery (60-80% able to VBAC)
129
VBAC Risks
- Maternal hemorrhage
- Infection
- Operative injury
- Hysterectomy
- Uterine Rupture: Incidence of 0.7% - 0.9%, declines with each successful VBAC
130
Uterine Rupture: S/S
```
Vaginal bleeding
Sharp pain between contractions
Contractions slow or become less intense
Bulging under pubic bone (baby’s head protruding outside of uterine scar)
Uterine atony
Maternal tachycardia
```
131
Uterine Rupture: Tx
Emergency C/S
| Supportive Care
