What is a leading cause of death in pregancy, caused by anesthetists?

What are 3 major perioperative goals with pregnant pts?

Failed intubation

maternal safety

fetal safety

avoidance of preterm labor

During pregnancy

Alveolar ventilation ______ by 25% at __months & 40-70% at ____.

FRC _____20%

MAC_____30%

What effect do the above respiratory changes have on induction & emergence? 

Alveolar Ventilation increased by 25% at 4 months and  40-70% at term

FRC decreased 20%

MAC decreased 30%

This leads to rapid induction and emergence

GI changes of pregnancy

Beyond the first trimester, consider any preganant patient...?

Seriously pregnant!

and...

a full stomach, and a risk for aspiration

Maternal oxygenation/ventilation

Uteroplacental perfusion

T/F: Teratogens are independent of dose & timing.

*Which organ system is as risk from affects of teratogens for the longest period of time?

*When are fetal organs most at risk during pregnancy?

*T/F: No anesthetic agents, or drugs routinely used during anesthesia are proven human teratogens.

FALSE--dose & timing dependent (usually cause issues when pt exposed for a long time with high dose)

CNS

weeks 2-8

True

T/F: Maternal hyperthermia & hypothermia are both associated w/ CNS anomalies

Radiation >___ rads is teratogenic

How does chronic hypoxemia associated w/ high altitude pregnancy affect the fetus? Is it teratogenic?

False!!

maternal hyperthermia is associated w/ CNS anomalies, but not hypothermia

Radiation >5-8 rads (CXR~8mrads)

Chronic hypoxemia is associated with lower birth weight, but is not teratogenic

Are benzo's teratogenic?

What was/is a concern w/ 1st trimester exposure to BZDs?

Conflicting reports - No evidence suggests a single dose would be harmful (but use can be avoided; discuss risk with mom & let her decide)

1st trimester exposure resulting in incr incidence of cleft lip, cleft palate

At what concentration and duration is Nitrous oxide harmful?

What effects does prolonged exposure to N2O cause? 

What is the presumed mechanism?

>50% for >24hrs

Prolonged exposure in humans produces neurologic and hematologic symptoms

Initially was thought to be inhibition of methionine synthetase & subsequent decr DNA synthesis - but some newer studies suggest that this may not be the only mechanism

*said dont worry about this much

What CNS changes does Halothane, barbiturates, and meperidine cause in rats?

Potentiation of ____ receptors and antagonism of ____ receptors in rats produces widespread neuronal apoptosis during the period of synaptogenesis

but the implications in humans are unknown

Postnatal learning change

CNS degeneration

Decreased brain weight

Potentiation of GABA receptors and antagonism of NMDA receptors in rats produces widespread neuronal apoptosis during the period of synaptogenesis

Severe maternal hypoxemia

Maternal hypotension

Uterine vasoconstriction

 Maternal hypotension compromises _______ blood flow?

What are 5 causes?

compromises uteroplacental blood flow

Excessive general anesthetic level

Sympathectomy following regional

Aortocaval compression

(always need left uterine displacement!!)

Hemorrhage

Hypovolemia

Increased circulating catecholamines

Alpha-adrenergic agonism

Toxic doses of local anesthetic

Procedures done during which time period carry the lowest risk for preterm labor?

Why else is this time frame better if must do a surgery in a pregnant pt?

Second trimester procedures not involving uterine manipulation carry the lowest risk for preterm labor.

less risk for fetal development issues d/t drugs here, b/c out of 2-8 week formative phase

What is risk of doing surgery in the 3rd trimester?

When should we give prophylactic tocolysis?

Larger uterus & thus more risk for uterine manipulation & subsequent stimulation of pre-term labor - per lec.

Selectively & in consultation w/ the pt's OB

What is the primary consideration in urgent or emergent situations?

At what point in pregnancy is transabdominal doppler for FHR possible?

But it may be difficult until ____?

possible at ~18 weeks

May be difficult until ~22 weeks

At the very least FHR should be checked ______ & on arrival in the ____

*Heart rate monitoring of a pre-viable fetus offers value as an indication to _____________.

At the very least FHR should be checked preoperatively & on arrival in the PACU

Heart rate monitoring of a pre-viable fetus offers value as an indication to optimize the maternal state (and thus helps us improve conditions for fetus too)

Mom may want to remember giving birth to her children.

Who knew?

also, possible risk for teratogen effect   

H2 blocker

Non-particulate antacid

Adequate ______ for regional anesthetic!!!!

The dose of local anesthetic is...?

adequate prehydration

Decreased

(d/t engorged epidural veins and thus decreased space)

In pregnancy, FRC is decreased.

In what position will the FRC further decrease?

What do we need to be sure to give them?

Supine (70% per lec)

Supplemental O2

Regarding GETA

***PREOXYGENATE***

What is necessary after the first trimester?

An ETT

and if the airway is suitable, a RSI is preferred

What are proven safe drugs for surgery during pregnancy?

Which 2 are prolly safe?

Which 1 is still questionable?

Pentathol

Opioids

NDMR

Sucs

Propofol

N2O

benzos

5 other anesthetic considerations for emergence

Careful monitoring of ____ level

Emergence may be ____

Risk for _____

Postop ___ measurement, intraop if possible

Postop _____ _______ monitoring?

Careful monitoring of MRs level

(pt will blow off gas fast and thus dont want your pt awake but still paralyzed)

Emergence may be rapid

Risk for aspiration

Postop FHR measurement, intraop if possible

Postop uterine contraction monitoring? (up to OB)

Decreased FRC

Decreased MAC

Increased Alveolar Ventilation

Which uterine incision provides less blood loss, heals better and stronger and is generally okay for a VBAC?

Which incision is risky for a VBAC?

Lower Transverse

classical longitudinal 

How does Prostaglandin gel (ripening agent) affect VBAC?

Should it be used?

Increases the risk of uterine rupture during VBAC substantially

Use is discouraged

How does Oxytocin affect VBAC?

What is required if it is used?

Mixed results

The use of oxytocin for VBAC requires close patient monitoring

Masking pain might delay the dx of uterine dehiscence or rupture

Sympathectomy would attenuate maternal compensation to hemorrhage

What is the most common sign of uterine rupture?

What are 4 other arguments for Labor Epidural and VBAC?

Fetal distress is the most common sign of uterine rupture NOT abd pain!!

1. Pain & uterine tenderness have low sensitivity for lower uterine segment scar dehiscence or rupture (don't always have pain even w/o epidural when rupture occurs - study with 1781 pts having a VBAC only 8 ruptured and 0 had any pain)

2. Pain and uterine tenderness have low specificity for lower uterine segment scar dehiscence or rupture

3. Epidural analgesia may not mask pain of dehiscence/rupture

4. Lower uterine segment scar dehiscence rarely results in significant hemorrhage

There is __ ____ evidence that epidural analgesia decreases the likelihood of vaginal delivery in VBAC.

Having a functioning epidural in place is advantageous should ______ ____ become necessary.

If you used epidural for a VBAC, may want to use more ____ LA concentrations.

There is no good evidence that epidural analgesia decreases the likelihood of vaginal delivery in VBAC

Having a functioning epidural in place is advantageous should emergent C/S become necessary

May want to use more dilute LA concentrations

Failed intubation

Inadequate ventilation/oxygenation

Aspiration of gastric contents

Hypertensive disorders of pregnancy

Obesity

Emergency procedures

Trends for anesthetic techniques with an C/S

GETA
Spinal

Epidural 

GETA↓ - decr. use unless emergency d/t incr. understanding of airway risks in preg.

Spinal↑ - spinal is king unless have preexisting epidural 

Epidural ↑ - inc. use b/c often in place for labor pain already

Preop Management of Pregnant Pt 

It is imperitive to look at the airway & ____ it!!

Is preop sedation necessary?

Are anticholinergics routinely used?

If anticholinergics are necessary, what is the best choice? Why?

document

sedation usually not necessary or even desired by the pt

anticholinergics rarely necessary

(undesirable effects--dry mouth, reduce LES tone)

Glycopyrrolate; doesn't cross placenta like atropine

Preop Management of Pregnant Pt

What is used for aspiration prophylaxis?

30ml non-particulate antacid (bicitra)

H2 blockers?

Metoclopramide?

would do all 3 if pt walks in and says "yep just ate 2 big macs" 

Preop Management of Pregnant Pt

What things are considered when assessing a patients fluid status?

*What is a standard fluid bolus?

*For preeclampsia?

Elective surgery - NPO status

Preeclampsia

Fluid bolus prior to regional

standard: 15-20ml/kg

preeclampsia: 7-10 ml/kg

Preop Management of Pregnant Pt

Includes availability of blood: ____ or _____.

Optimize position to avoid...?

What type of O2 admin is usually appropriate?

T&S or hold clot

Aortocaval compression

(position: L uterine displacement; also need O2, standard maternal monitors & fetal monitoring when appropriate)

NC

IV fluids

Left uterine displacement

Prophylactic vasopressor? (old school & "stupid")

Ephedrine or Phenylephrine?

Support the airway, intubate if necessary

100% O2

Support circulation

Subdural block

Although it's mainly a problem of the past, when has local anesthetic toxicity been a problem?

What do we use to treat this?

With the use of Bupivicaine in higher concentration(0.5-0.75%) formulas

Lipid therapy

Easy

Quick

Awake patient

Dense block

High success rate

Minimal drug use

Cheap

Safe

Whats bad about spinal techniques? (6)

also see slide 39

Rapid sympathectomy

Slower than GETA (but faster then epidural)

Awake patient (good and bad)

Coagulopathy

Patient Refusal

Cardiac contraindications

Sometimes the touhy needle may be useful as an introducer for the spinal needle in a ____ shot technique.

What's good about epidurals? (6)

see slide 41

single shot

Often in place for labor already

Slower onset of sympathetic block

Less intense motor block

Ability to redose

Useful for post op pain control

Awake patient

What's bad about epidurals? (5)

When will you lose the good effect of slow onset of a sympathectomy with epidural?

Large volumes of drug

Slower onset of anesthesia

Less intense analgesia

Unintentional dural puncture

Venous puncture or migration

If you slam a huge dose rapidly with epi in it

What's good about general anesthesia?

What are 6 indications for GA?

Fast

Indications:

Dire fetal distress w/o a preexisting epidural

Acute maternal hypovolemia

Coagulopathy

Inadequate regional anesthesia

Refusal of regional

Lack of patient cooperation

What's bad about general anesthesia? (3)

see slide 44

Airway concerns

Aspiration

Patient unable to participate with birth

Ectopic Pregnancy

(Increased almost 5x from 1970 to 1992)

What defines an ectopic pregnancy?

92% of deaths frome ectopic pregnancy are from...?

any pregnancy outside of the uterus

-98% are in the fallopian tubes per Ron

Hemorrhage

Prior tubal surgery

Inflammation (prior PID)

Congenital anatomic distortion

Previous pelvic/abdominal surgery

Concurrent IUD use

Delayed ovulation

Assisted reproductive techniques

Abdominal or pelvic pain (90-100%)

Delayed menses (75-95%)

Vaginal bleeding (50-80%)

If the infant survives an abdominal pregnancy, what may be the result?

What happens when removing the placenta in this situation?

The placenta will be poorly perfused & may result in fetal growth restriction & oligohydramnios

Removal of the placenta is problematic, may lead to massive hemorrhage & require additional surgery

What is a double setup?

What is included in the double setup?

How do you manage the epidural?

What should you be prepared for?

Allowing the pt to deliver in the OR, but being ready for RA C/S or GETA if needed...often seen with twin births when one is breached.

Same as for any case

Assess the patients airway

Aspiration prophylaxis

Supplemental oxygen

Standard monitors

Keep an anesthesia record

If epidural is in place, dose in consultation w/ the OB (when and if needed)

Be prepared to rapidly advance your epidural level and/or proceed to general anesthesia

What are the advantages of immediate PPBTL? (4)

(postpartum tubal ligation)

Lower complication rate w/ minilap than w/ laparoscopy

Avoids cost of a 2nd hospitalization

May have an epidural in place already

Simpler for surgeon

LAMs

Multiparous women are at increased risk of uterine atony & postpartum hemorrhage

Assessment of the newborn may not be complete (if any question about the baby's survival dont do PPBTL)

Inadequacy of staffing for unscheduled, elective surgeries

Consent issues

Physical signs of hemodynamic instability

Laboratory evidence of excessive blood loss

Questionable condition of the neonate

Patient is at all hesitant or ambivalent

Patient with coexisting cardiac disease

Worldwide, 75% of PPBTL are done...?

In US?

With infiltration of local anesthetic

In the U.S. most are done with a regional anesthetic and laproscopy

What regional technique is preferred with PPBTL?

How does the incidence of hypotension during spinal for PPBTL compare to C/S?

Epidural with existing catheter in place (best success rate on reactivating catheters within 24 hrs)

or

Spinal preferred in the absence of an epidural catheter or with failure of epidural catheter reactivation

Greatly decreased incidence of hypotension relative to spinal for C/S

Regarding GETA for PPBTL...

How do volatile agents affect uterine tone?

When is it usually too late to reactivate an epidural?

Volatile agents may inhibit uterine tone

after about 24hrs per Ron

False

Insignificant amounts of drug are present in breast milk by 4 hours postoperatively

Mesosalpinx w/ LA

-great post op pain

In the 1st stage of labor, pain results from _____ dilation & ______ of the lower uterine segment w/ contractions.

How is pain during this stage transmitted?

In the 1st stage of labor, pain results from cervical dilation & distention of the lower uterine segment w/ contractions.

Slow conducting A-delta and C fibers (Visceral afferents)

What does the pain in the second stage of labor result from?

How is it transmitted?

The distention of the pelvic floor, vagina, & perineum

Transmitted by rapidly conducting somatic nerve fibers

Why is Bupivicaine the most commonly used drug for labor epidurals?

What are we concerned about with bupivicaine?

Excellent sensory analgesia w/ minimal motor block

cardiotoxicity w/ high concn

Thought to be less cardiotoxic than bupivicaine

Longer duration of action than bupivicaine

Rapid onset

Very short half life in maternal & fetal blood

Reduces efficacy of subsequently admin bupivicaine & opioids

Implicated in back pain following large epidural volumes??

False!

Epidural infusion pumps should be distinct from the IV infusion pumps

Epidural tubing should be unique, have no injection ports, and be labeled "epidural"

Patient refusal or inability to cooperate

Incr. ICP 2ndry to a mass lesion(but ok w pseudo tumor cerebri)

Skin or soft tissue infection at the site of needle placement

Frank coagulopathy

Uncorrected maternal hypovolemia

Inadequate training or experience w/ the technique "if you suck" =-)

You're in the wrong place

or

You forgot to add the drug

You forgot that you work down in the cafeteria now because you couldn't do anesthesia

Catheter has become dislodged

Catheter migrated

Disconnect from the infusion pump

Change in nature of labor--Have obstetrician examine the patient

Improperly positioned catheter

Anatomic barrier to diffusion - epidural adhesions

Drug problem

-dont see as much now d/t opioids

What is the 1st thing to do to manage a spotty epidural?

If the catheter is in the epidural space but the block is asymmetric?

Evaluate if the catheter is actually in the right place, replace if in doubt

Withdraw the catheter 0.5-1cm, place less blocked side in dependent position, and increase the volume (and decrease the concentration) of the local anesthetic; replace if unsuccessful

Ask the OB to evaluate the progress of labor

Check for bladder distention

Increase the volume and/or concentration of local anesthetic, or add an opioid to the solution of LA

Severe back pain

Significant delay in normal recovery 

Deterioration of lower limb function

Deterioration of bladder function

Backache

Abnormal neurologic findings

Increased temperature

False!!

No causal relationship

Abnormal neuro findings almost ___ r/t epidural, but always warrants prompt ___ & ____ if serious problems suspected.

Epidural hematoma symptoms will likely include what 3 things?

Abnormal neuro findings almost never r/t epidural, but always warrants prompt examination & consultation if serious problems suspected.

back pain

bilateral findings

progression of symptoms

Increased temp is not normal following prolonged epidural. T/F?

Why?

False it is very common (1-2 degrees)

unclear - Result of sympathetic block, or resetting of thermostat