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71 Cards in this Set
- Front
- Back
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What is a C-Section?
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Delivery of infant thru incisions in abd and uterine walls
Incidence increasing- Up to around 40% People have elective c sections now |
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Choice of anesthesia for c-section depends on ....
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why, how quick, what patient wants, judgment of provider
STAT c-sections when unexpected complication arises – no time for regional Urgent when mom or fetus not in immediate danger – consider regional vs. general |
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Need for STAT C-section
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Massive bleeding
Prolapsed cord Severe fetal distress Eclampsia Abruptio placentae Ruptured uterus |
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Need for urgent c-Section
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Repeat c-section (mom came in in labor)
Failed induction Failure to progress Failed forceps delivery Chorioamnionitis Malpresentation Mild-moderate fetal distress |
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Spinal Anesthesia for C-section ADvantages
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Easy to perform
Rapid induction Reliable Minimal drugs to fetus Awake mom - mom can meet baby ↓ risk of aspiration |
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Spinal Anesthesia for C-section Disadvantages
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-Hypotension in app 80%:
Sympathetic block and compression of aorta and vena cava If for no more than 2 min, no observed newborn depression If prolonged, neuro changes in baby for up to 48 hours Prevention by preload 1-2 L non-dextrose crystalloid Treat with ephedrine 5-15 mg increments If tachycardia – may give phenylephrine in small doses (50-100 mcg) without harming fetus -Limited duration of action of Spinal -N/V: From hypotension, traction on peritoneum or other viscera (vagal response) - won't always see bradycardia though Treatment – correct hypotension, adequate regional block helps prevent – adding opioid helps -PDPH: Use small gauge pencil-point needle 5.2% with 27g Quincke, 1.1% with 25g Whitaker Some think parallel insertion of needle reduces risk |
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Spinal Anesthesia for C-section: Locals Chosen based on duration of action needed
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Hyperbaric:
0.5% tetracaie 90-120 min 5% lidocaine 45-60 min 0.75% bupivacaine 90-120 min |
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T or F: Intrathecal meperidine 1 mg/kg has been used alone with success
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True: Duration of anesthesia 45-60 min
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Opioid adjuncts for Spinals
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Sufentanil 10 mcg
Fentanyl 10-25 mcg Morphine 0.1-0.3 mg |
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Spinal Anesthesia for C-section Technique
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Hydrate – 1-2 L via 18g IV
Reglan 10 mg Zantac 50 mg IV Bicitra 30 mL PO Transport to OR Monitors Sitting position or R lat position Use smallest non-cutting needle possible Inject meds: 8-10 mg tetracaine (0.8-1.0 mL 1%) 60-75 mg lidocaine (1.2-1.5 mL 5%) 7.5-15 mg bupivacaine (1.0-2.0 mL 0.75%) Add: Fentanyl 10-25 mcg (0.2-0.5 mL) Preservative free morphine 0.1-0.3 (0.1-0.3 mL Astramorph 2mg/2mL) Epinephrine 0.1-0.2 mg Place supine with LUD O2 via facemask Provide for close monitoring of delayed resp depression Write orders! |
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Epidural Anesthesia for C-section ADvantages
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Less hypotension
Avoids dural puncture (hopefully) Can be redosed (used for longer surgeries) Especially useful in morbidly obese |
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Epidural Anesthesia for C-section Disadvantages
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More complex – greater chance of failure
Slower onset Takes more meds |
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Epidural Anesthesia for C-section Complications
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-Unintentional IV injection in 2.3%
-PDPH in app. 80% if dura punctured -Shivering in 14-64% Don’t know why – fentanyl to epidural helps -VAE – 9.5-65% (some say up to 97%) Can happen with epidural, SAB and GA SX – chest pain, dyspnea, EKG changes, decreased SaO2, hypotension, tachycardia M/M rare |
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Epidural Anesthesia for C-section Locals
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Need higher concentrations for surgery:
Bupivacaine 0.5% 75-90 min Chloroprocaine 3%30-40 min Lidocaine 2% with epi 75-90 min |
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Opioid adjuncts
for epidurals |
Fentanyl 50-100 mcg
Morphine 3-5 mg |
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Dermatome requirement for epidurals
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Requires 1 mL per dermatome level in parturient
18 dermatomes for T4 (expect to give 20-25 mL) |
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Epidural Anesthesia for C-section Technique
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1-2 L IVF
Reglan, Zantac, Bicitra Place epidural and test – if negative Administer load in 5 mL increments May start in patient’s room Monitor FHR and mom’s B/P throughout In OR – Monitors, LUD, & O2 via facemask If existing epidural when C-section decided Stop infusion, slowly inject local, monitor level, usually takes less |
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General Anesthesia for C-section Advantages
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Speedy induction
Reliable Avoids hypotension (More likely to see hypertension from light anesthesia) |
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General Anesthesia for C-section DisAdvantages
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Risk of aspiration
Difficult AW Narcotization of neonate Awareness |
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General Anesthesia forC-section COmplications
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Failed or difficult intubation leading cause of anesthetic related maternal mortality
Incidence much greater on OB than usually: Full dentition Laryngeal/pharyngeal edema Difficult placement of laryngoscope (large breasts) Failure to allow sux to work Plan and AW adjuncts must be available |
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If difficult or impossible to ventilate Mom ....
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WAKE HER UP or establish surgical AW
Maintain cricoid pressure throughout all attempts, procedures to secure AW Communicate with surgeon anytime difficult AW anticipated You have fast-track LMA in place after failed intubation. Can’t insert ETT through fast track. Can ventilate patient. WHAT NOW? Maintain cricoid and use LMA. |
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IS Neo or Ephedrine safer for baby?
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Neo causes less acidosis, so it is safer.
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If mom is Hypotensive and HR is 80 what is the drug of choice?
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Ephedrine
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If mom is Hypotensive and HR is 100 what is the drug of choice?
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Neo
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If mom is Hypotensive and HR is 90 what is the drug of choice?
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who the fuck knows?
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What is the problem with spinals and c-sections for the obese or a repeat c-section with a lot of scar tissue?
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May run out of time and need to redose.
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T or F: The Pencan needle is close to the Whitacre
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True
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T or F: Morphine neuraxial can exacerbate herpes
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True...yuck
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OB pts usually shiver, with or without neuraxial anesthesia, what is the % of incidence for shivering?
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10
Goes up to 70% with neuraxial though |
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Can you check the pts level with the PNS
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yes, on a low setting.
can use alcohol pad too |
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What is the incidence of OB failed or difficult intubation compared to the general OR population?
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1:250 OB compared to 1:2000 OR
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General Anesthesia for C-section Neonatal Depression
CAuses |
Maternal hypoventilation
Maternal hyperventilation Aortocaval compression Drugs Incision to delivery time |
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Category A drugs
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Studied in women – no risk demonstrated in 1st trimester
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Category B drugs
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Animal studies – no risk to fetus OR
Animal studies – adverse effects but studies in women show no risk |
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Category C drugs
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Teratogenic effects in animals
No human studies |
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Category D drugs
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Evidence of human fetal risk but benefits may outweigh risks in some situations
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Category X drugs
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Fetal risk and benefits do not outweigh risk
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General Anesthesia for C-section – Neonatal Depression
Induction Agents |
Thiopental:
Rapidly crosses placenta Detected in umbilical blood within 30 sec Single IV dose 4 mg/kg doesn’t depress neonate Ketamine: Agent of choice in hypovolemic patient No neonatal depression in 1 mg/kg dose or less Etomidate: 0.2-0.3 mg/kg May see production of cortisol depressed in neonate Propofol: Recently approved for pregnant patients as Category B drug but not recommended for RSI 2-2.5 mg/kg No benefit over thiopental according to Datta |
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General Anesthesia for C-section – Neonatal Depression
Muscle relaxants |
Highly ionized
Little effect on newborn Prolonged effect from sux in Mom and baby if atypical plasma cholinesterase in both Most say don’t need defasciculation dose of MR Fasciculations rare Mom may get weak Muscle pain negligible after sux used for section |
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General Anesthesia for C-section – Neonatal Depression
N2O |
Rapidly crosses placenta
Don’t use higher than 50% |
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General Anesthesia for C-section – Neonatal Depression
Halogenated agents |
Don’t depress newborn at less than 0.5% MAC
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Maternal awareness
during GA |
17-36% incidence
Low volatile concentration Agent and BIS monitors help Likely to remember incision - ?time to place BIS in emergency? |
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If use etomidate and If have trouble with BP in neonate may consider a steriod, why?
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etomidate can cause decreased production of cortisol.
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Effect of induction-delivery and uterine incision-delivery intervals
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Not a factor in regional if no hypotension
If induction-delivery > 8 min or uterine incision-delivery > 3 min Lower 1 min Apgar and umbilical artery acidosis likely Decrease times by having patient, surgeon, OR team ready for incision before induction Notice time of uterine incision – want less than 3 min until baby BLOOD FLOW STOPS WITH UTERINE DECISION |
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General Anesthesia for C-section
Technique |
Premeds same as regional
Monitors, LUD Preoxygenate Cricoid pressure when all ready Thiopental 4 mg/kg & sux 1.5 mg/kg Intubate in 30-60 sec O2 and no more than 0.5 MAC volatile Some say 50% N2O OK Avoid hyper/hypoventilation NDMR as needed OG tube After umbilical cord clamped Deepen anesthesia with N2O, narcotic, continue volatile, Versed Pitocin 30 u to 1000 mL IVF Antibiotic **Extubate when wide awake** |
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Regional vs. GA – condition of neonate
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Some say lower 1 min Apgar scores with GA
Some say no difference Key seems to be length of time for skin incision to delivery and uterine incision to delivery with GA |
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Post-Partum Sterilization:
Advantages and Disadvantages |
Advantages
Tubes easy to reach before involution of uterus No increase in hospital stay Less medical cost Disadvantages Physiological changes of pregnancy for 6 weeks Dr. Datta – shouldn’t provide GETA for any patient with full stomach for elective procedure |
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Post-Partum Sterilization
Guidelines |
If epidural works, can be used and surgery may be done when stable after delivery
If epidural fails, usually wait 8 hours for GA or SAB Some say waiting > 48 hrs increases risk of infection from bacteria produced by uterus --ACOG recommendations OK immediate PP period if mom stable and existing anesthesia Up to anesthesia if requires major induction of anesthesia (SAB or GA) If complications during pregnancy or delivery - postponed |
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Post-Partum Sterilization:
procedure and Anesthetics |
Procedures same as for C-section
T4 level desired Anesthetics and breast milk Most maternal drugs appear in breast milk Narcotics insignificant amounts – OK Thiopental in breast milk – insignificant effects on newborn – OK Propofol rapidly cleared and OK Avoid benzos, atropine and antihistamines Decrease lactation and anticholinergic SE in infant |
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Anesthesia for Abnormal Positions and Multiple Births
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-90% single gestation fetuses
Cephalic presentation Occiput transverse or anterior -Others considered abnormal Persistent occiput posterior (OP) Face, brow, breech, shoulder -OP common in early labor |
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Internal rotation of occiput normal during descent
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See arrested descent if doesn’t happen
Severe back pain Pressure on sacral nerves by occiput More work during delivery Harder to push Cervical & perineal lacerations more common Forceps may be required (or vacuum) |
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Breech presentations in 3.5% of pregnancies
Name the 3 types and distinguish b/t |
Frank breech (60%)
Legs flexed at hips, extended at knees, feet at face Complete breech (10%) Legs flexed at hips and knees, butt and feet at cervix Incomplete breech (footling – 30%) One or both legs extended – foot in vagina |
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Breech presentation can deliver vaginally if
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Small infant
Frank presentation Facility, physician, anesthesia ready for emergent C-section Mom’s pelvis is ready Good dilation, effacement, descent C-section most common for delivery |
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Multiple gestations
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Twins – 1 in 90 births
Triplets – 1 in 8,000 |
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Vaginal delivery with twins possible
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Both vertex 39% of the time
One vertex and one breech 37% of time Epidural good choice Usually go to surgery room for delivery C-section may be needed to deliver 2nd baby Ready to go to sleep if becomes emergent |
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More likely to see problems during pregnancy and L&D with multiple gestations
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Preeclampsia-eclampsia, anemia, premature labor, prolonged labor, antepartum and postpartum hemorrhage
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____% of twins are premature, higher mortality rate, 2nd twin more likely to need resuscitation
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60
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Why is the second fetus more likely to need resusicitation?
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B/c of the uterus to delivery time...blood flow stops with uterine cut.
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Anesthesia for General Surgery During Pregnancy
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Incidence 1 in 116
0.5-2.2% or 50,000/yr in US (Datta) Plan for maternal safety Physiological changes of pregnancy by 2nd trimester Teratogenicity May be caused at any stage of gestation and detected at birth or later To produce defect, drug must be given in appropriate dose during particular developmental stage of embryo to individual with particular genetic susceptibility |
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Anesthesia for Surgery During Pregnancy - Teratogenicity
what drugs are ok? |
Critical stages of organ development first trimester
Regional good choice especially in 1st trimester Volatiles are not associated with teratogenicity, thiopental, fentanyl considered OK See no difference in congenital anomalies after anesthesia See increased incidence in spontaneous abortion especially if in 1st and 2nd trimesters MR OK |
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Use of N2O during 1st and 2nd trimesters addressed by FDA
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May be contraindicated
Inactivates Vitamin B12 Essential cofactor of methionine synthetase which interferes with folate metabolism Result is impaired DNA synthesis |
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What do you avoid with anesthesia in surgery of pregnant pt?
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Avoid benzos
Avoid hypoxia and hypercarbia Anomalies in animal studies |
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Increased congenital anomalies & spontaneous Abs in staff in OR and dental offices that use inhalational agents
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Some say no correlation
Scavenging system should be used ? Use of N2O in pregnant OR staff |
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Anesthesia for Surgery During Pregnancy – Prevention of Fetal Asphyxia
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Maintain normal maternal pO2, pCO2 and uterine blood flow by Good AW management:
Maternal hyperoxia Some ? vasoconstriction in presence of elevated O2 tension may lead to decreased uteroplacental blood flow No evidence in any study Cannot cause retrolental fibroplasia or closure of DA in utero Proper regional block management Maintain maternal normocarbia |
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Anesthesia for Surgery During Pregnancy – Prevention of Fetal Asphyxia by Preventing maternal hypotension...HOw?
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Shnider says decrease in UBF if B/P ↓ 15-30%
Maintain systolic B/P > 100 mm Hg |
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Prevention of Fetal Asphyxia by Avoiding uterine vasoconstriction and hypertonus which is caused by what?
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uterine vasoconstriction and hypertonus is Caused by
Endogenous or exogenous sympathomimetics (↓ UBF) Local toxicity (vasoconstriction) Ketamine in doses > 1.1 mg/kg (↑ uterine tone) |
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Anesthesia for Surgery During Pregnancy – Prevention of Preterm Labor
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Associated with abdominal procedures with uterine retraction or manipulation
Effect of different anesthetic techniques on preterm labor unknown Some MDs put patients on prophylactic Brethine or Ca++ channel blockers |
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Anesthesia for Surgery During Pregnancy – Recommendations for Management
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Delay elective surgery until after delivery, urgent until 2nd trimester
Use regional if possible in emergency especially in 1st trimester Aspiration precautions if after 12th week (Datta) and GA necessary LUD in 2nd and 3rd trimesters Monitor FHR and uterine activity after 16th week Be prepared to give tocolytics if necessary |
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Anesthesia for Surgery During Pregnancy – Reassurance to parents
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NO ANESTHETIC DRUG – pre-med, induction agent, volatile, or local – HAS BEEN PROVEN TO BE TERATOGENIC IN HUMANS
Likelihood of 1st trimester miscarriage increases from 5.1% without surgery to 8% with Risk of premature delivery increases from 5.13%-7.47% |
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What route does baby get less drug?
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SAB
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Benzos can cause what to fetus?
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Cleft palate
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