1. Anesthetic and Analgesic Methods Used for OB Anesthesia New Innovations
Joseph E Pellegrini, PhD, CRNA
Associate Professor
Deputy Program Director
University of Maryland Nurse Anesthesia Program

2. Obstetrical Anesthesia
Evolution taking place
Use of CLE  from 16% in 1985 to > 50% in 2000
Practice changes
Introduction of new drugs, techniques, and delivery apparatus
Consumerism
Litigation
Increased demands on Anesthesia Providers
24/7 coverage
Increased research in OB anesthesia arena
Promoted changes in Anesthesia Dept. guidelines

3. Goals of Laboring Analgesia
Principle Goal
Delivery of a healthy neonate
Expelling the fetus & placenta
Three distinct stages of Labor
Each stage has different analgesic requirements

4. Pain of Parturition

5. Pain Centers during labor progression

6. Initiation of Epidural Analgesia
Continue to have controversy as to when to initiate epidural analgesia
Some advocate waiting until 4 cm dilatation whereas others initiate at request
Early initiation associated with prolonged stages of labor
Early initiation associated with increased dystocia, instrumental and operative delivery rates
Recent study dispute these claims

7. Early
Late
Early
Late

8. Outline New Innovations for Laboring Analgesia
CSE Technique
Patient Controlled Epidural Analgesia
With or without a basal infusion rate
With or without predetermined timed boluses
New Innovations for Cesarean Section
Opioids administered for postoperative analgesia
DepoDur for postoperative analgesia
Side effect prophylaxis
Control of opioid induced side effects

9. The CSE Technique
Viewed as most significant advancement in OB anesthesia in the last decade
CSE - Usually performed using a needle-thru-needle technique
Intrathecal opioids very effective in controlling 1st stage labor pain
Fentanyl ug or Sufentanil ug with/without morphine mg and/or bupivacaine 2.5 mg
Addition of bupivacaine efficacy in question – typically not efficacious for 2nd stage labor pain
Need adequate amounts of local anesthetics to effectively block the pain for 2nd stage labor pain
Routinely administered via CLE

10. The CSE Technique
CSE technique often given in combination with an epidural infusion
Traditional Method –
Bolus before infusion
Traditional Admixtures
.125% - .25% Bupivacaine with/without mcg fentanyl
.2% Ropivacaine with/without mcg fentanyl
CLE infusion (continuous infusion)
% Bupivacaine with or without 1-2 mcg/ml fentanyl at 8-15 ml/hr
Ropivacaine with or without 1-2 mcg/ml fentanyl at 8-15 ml/hr
Alternative Method -
Patient Controlled Epidural Analgesia (PCEA)
Becoming more popular in OB anesthesia practices
Often administered immediately following placement of intrathecal opioids with small basal rates and set maximum hourly dose
Advantages
Less variability in the peak plasma concentration of drug
Faster onset of analgesia
Titrate able
Greater pain control and Satisfaction scores noted when compared to traditional continuous infusion rates

11. CSE for Cesarean Delivery
CSE use during c-section associated with higher sensory blockade
Conflicting results
Both studies - CSE performed without injection or catheter placed into epidural space
Anecdotal information – no differences noted in my own clinical practice when epidural catheter placed
Noted difference if test dose administered following IT injection
Epidural often used for placement of Morphine & 10 ug fentanyl administered via IT injection with mg hyperbaric bupivacaine
Possible difference is lateral orientation of spinal needle during injection as opposed to cephalad orientation

12. Patient Controlled Epidural Analgesia
PCEA accords laboring women autonomy in pain relief for labor and has been shown to very effective and desirable
Wide variety of dosing options
Often dependent whether or not initial bolus dose administered following test dose
Greater degree of maternal satisfaction reported when PCEA compared to conventional continuous infusion

13. Maximum hourly dose (ml)
Recipes for PCEA
Anesthetic Solution
Basal Rate
(ml/hr)
Bolus Dose
(ml)
Lockout interval
(minutes)
Maximum hourly dose (ml)
Bupivacaine 0.125% 4 20
+ fentanyl 2 mcg/ml
(if bolus given) 5 3 7 18
(if bolus not given)
6-8 25
Bupivacaine 0.25% 10
Bupivacaine 0.1% 26
Ropivacaine 0.125% 6 24

14. PCEA versus Conventional therapy
From Gambling DR, McMorland GH, Yu P, Laszlo C. Comparison of patient-controlled
epidural analgesia and conventional intermittent “top-up” injections during labor. Anesth
Analg 1990: 70:

15. PCEA
Traditionally PCEA is administered with or without a basal infusion rate
Some clinicians report that basal infusion rates not required
Omitting a basal infusion rate reduces analgesic consumption but conflicting results regarding effect on stage 2 labor and satisfaction
Recently conducted study analyzing effect on maternal hemodynamics, fetal and neonatal hemodynamics, length of stage 2 labor, effect on mode of delivery and maternal motor function and overall maternal analgesic satisfaction

16. Primary questions? Methods
Webster A, Lawson S, Nezat G, Pellegrini JE. Comparison of outcomes between groups of parturients administered PCEA laboring analgesia with and without a continuous basal infusion Unpublished Data
Primary questions?
What are the differences in relation to overall analgesic requirements and maternal, fetal and neonatal outcomes between groups of parturients administered a PCEA for laboring analgesia with or without a background basal epidural infusion
Methods
100 subjects enrolled
CSE technique used – all parturients administered 10 mcg intrathecal fentanyl
Parturients consented and randomized to receive PCEA laboring analgesia with or without a background basal infusion rate
One group received PCEA alone using 0.2% ropivacaine 5 ml boluses with a 15 min lockout (total of 20 ml/hr)
One group received PCEA using 0.2% ropivacaine 5 ml boluses with a 15 min lockout in combination with a background infusion of 0.2% ropivacaine of 5-10 ml/hr (maximal total set at 30 ml/hr)

17. No differences in demographic variables
Webster A, Lawson S, Nezat G, Pellegrini JE. Comparison of outcomes between groups of parturients administered PCEA laboring analgesia with and without a continuous basal infusion Unpublished Data
No differences in demographic variables
No differences in VNRS scores for pain at any interval measurement
Measured q 5 minutes following initiation for 30 minutes then q 1 hour thereafter until delivery
No differences in mode of delivery
SVD (72% in PCEA group;80% in PCEA + CLE group)
Instrument assisted (5% in PCEA group; 4% in PCEA + CLE group)
Cesarean Section (23% in PCEA group; 16% in PCEA + CLE group)
No differences in analgesic satisfaction scores
Both groups reported satisfaction or complete satisfaction with laboring analgesia

18. Webster A, Lawson S, Nezat G, Pellegrini JE
Webster A, Lawson S, Nezat G, Pellegrini JE. Comparison of outcomes between groups of parturients administered PCEA laboring analgesia with and without a continuous basal infusion Unpublished Data

19. Webster A, Lawson S, Nezat G, Pellegrini JE
Webster A, Lawson S, Nezat G, Pellegrini JE. Comparison of outcomes between groups of parturients administered PCEA laboring analgesia with and without a continuous basal infusion Unpublished Data

20. Webster A, Lawson S, Nezat G, Pellegrini JE
Webster A, Lawson S, Nezat G, Pellegrini JE. Comparison of outcomes between groups of parturients administered PCEA laboring analgesia with and without a continuous basal infusion Unpublished Data
Conclusions
Preliminary Data
No differences in level of analgesia afforded
PCEA alone supports previous studies regarding analgesic consumption
Noted shortened stage 2 labor in PCEA alone group but no adverse effects on mode of delivery
Both are viable options but data reported is preliminary
Despite findings many practitioners prefer inclusion of basal rate with PCEA
Novel approach to basal rate recently investigated
Recent investigation analyzing differences between groups of parturients that received either traditional PCEA + basal continuous infusion or PCEA with automated mandatory boluses

21. Oxytocin at Cesarean Section
Oxytocin is routinely administered following delivery
Oxytocin can be administered immediately after delivery of the shoulders, before or after delivery of the placenta
If administered before delivery of placenta decreased blood loss has been observed
Controversy exists concerning infusion versus bolus or combination
Infusion traditionally initiated at mU/min (20 10 ml/min or 7.5 ml/min) for several minutes until the uterus firmly contracted and no active bleeding noted
Effect of oxytocin dependent on number of oxytocin receptors
Pregnancy causes a 180 fold increase in concentration of oxytocin receptors with the greatest increase occuring just before the onset of labor
Administration of rapid IV bolus may cause significant hypotension & cardiovascular collapse
Some practitioners advocate administration of a single IV bolus of 2-5 units of oxytocin at time of delivery (most often in addition to infusion)
Studies have shown that administration of a 10 unit bolus can result in complete cardiovascular collapse

22. Bottom Line:
Be vary cautious in administration of oxytocin bolus especially when faced with parturient with low
MAP & Maternal pulse – can result in complete cardiovascular collapse

23. Cesarean Section – Postoperative Analgesia
Spinal Anesthesia
70% of all elective cesarean sections are performed using SAB
Approximately 90% receive intrathecal morphine for postoperative analgesia
Dose ranges from 0.10 – 0.30 mg
Analgesia efficacy from hours
Moderate to high side effect profile - some studies indicating higher profile when ITN used as compared to when epidural morphine is administered
Epidural Anesthesia
Routinely used when epidural analgesia is used for labor
Estimated that over 90% received PF Morphine Sulfate for postoperative analgesia
Dosing regimen administered (2-5 mg)
Duration of action hours
Side effect profile moderate to high
Studies using conventional PF Morphine at increased doses fail to yield longer durations of action
Recently investigations have been done using extended release liposome injection morphine (DepoDur)
Formulated in an attempt to increase the duration of analgesic action of epidural morphine

24. Depo-Dur
DepoDur (morphine sulfate extended-release liposome injection) is a sterile suspension of multivesicular liposomes using proprietary DepoFoam® formulation technology containing morphine sulfate, intended for epidural administration.
DepoFoam is a drug delivery system that encapsulates the morphine sulfate and allows it to be released slowly over time for a period of approximately 48 hours
Allows analgesia for approximately twice as long as conventional DuraMorph
Traditionally DuraMorph administered to cesarean section patients in doses ranging from 2-5 mg
Depo-Dur administered to cesarean section patients in doses ranging from 5-15 mg
Studies indicate a ceiling dose effect achieved at 10 mg
Recent study analyzed effect between groups of cesarean section patients administered either 10 mg DepoDur or 4 mg DuraMorph
Enrolled 70 ASA 1 and 2 cesarean section patients to receive one of the two regimens
Analyzed differences in analgesic requirements, pain scores, postop activities and side effects between the groups

25. Carvalho B, Roland, LM, Chu LF et al
Carvalho B, Roland, LM, Chu LF et al. Single-dose, extended release epidural morphine (DepoDur™) compared to conventional epidural morphine for post-cesarean section pain. Anesth Analg 2007; 105:

26. Carvalho B, Roland, LM, Chu LF et al
Carvalho B, Roland, LM, Chu LF et al. Single-dose, extended release epidural morphine (DepoDur™) compared to conventional epidural morphine for post-cesarean section pain. Anesth Analg 2007; 105:
(At rest)
(With Activity)

27. Carvalho B, Roland, LM, Chu LF et al
Carvalho B, Roland, LM, Chu LF et al. Single-dose, extended release epidural morphine (DepoDur™) compared to conventional epidural morphine for post-cesarean section pain. Anesth Analg 2007; 105:

28. Carvalho B, Roland, LM, Chu LF et al
Carvalho B, Roland, LM, Chu LF et al. Single-dose, extended release epidural morphine (DepoDur™) compared to conventional epidural morphine for post-cesarean section pain. Anesth Analg 2007; 105:
DepoDur provided longer latency of analgesia and greater satisfaction
Better analgesia (but was it clinically significant?)
Both conventional and Extended released morphine solution resulted in moderate to high side effect profiles
Side effects reported in the range of 20-60% for PONV & % for pruritis
Side effects traditionally treated with oral histamine blockers (questionable efficacy), antiemetics or opioid antagonists (often at the expense of analgesia)
There has been no definitive treatment regimen for treatment of side effects identified to use in post-cesarean section population
What can we give to treat or prevent side effects in the parturient population that has been given neuraxial morphine sulfate?
Recent study analyzed effect of prophylactic IM promethazine in groups of c-section patients administered intrathecal morphine for SAB

29. Promethazine Common antiemetic agent used in OB
Possesses strong anticholinergic and antihistamine properties
Two studies noted that when Promethazine administered as antiemetic agent to groups of patients administered epidural/intrathecal morphine noted a significant reduction in PONV and pruritis
Both studies used small sample sizes (<20 patients)
Not used in OB population
Study design not specific to measure pruritis
Study performed to determine if promethazine effective in preventing PONV & pruritis in a cesarean section population administered intrathecal morphine

30. Enrolled 60 ASA 1 & 2 subjects scheduled for elective cesarean section
Litchfield, J, Pronk C, Nezat G, Pellegrini JE. Effect of 25 mg IM promethazine on the incidence and severity of PONV and pruritis in a cesarean section population receiving intrathecal morphine. Accepted AANA J 2008
Enrolled 60 ASA 1 & 2 subjects scheduled for elective cesarean section
All subjects administered SAB with 12 mg bupivacaine, 10 mcg fentanyl and 0.3 mg Dura Morph
Randomized to receive either 25 mg IM promethazine or placebo in vastus lateralis immediately after SAB placed
Double blind
Placebo Controlled
Informed consent

31. Demographic Variables
Promethazine
Placebo
Gravida (range)
1-7
Parity (range)
0-3
0-4
Ethnicity
Caucasian (N)
African-American (N)
Hispanic (N)
Asian (N) 18 8 4 19 6 3 2
Height (Mean inches ± SD)
64 ± 2.4
64 ± 2.0
Weight (Mean Kg ± SD)
89 ± 17
85 ± 14
Total Surgical Time (Mean min ± SD)
47 ± 18
45 ± 17
Total PACU Stay (Mean min ± SD)
125 ± 42
125 ± 57
Litchfield J, Pronk C, Nezat G, Pellegrini JE. Effect of 25 mg IM promethazine on the incidence and severity of PONV
and pruritis in a cesarean section population receiving intrathecal morphine. Accepted AANA J

32. Promethazine Prophylaxis Study Findings
No difference in level of pain on injection noted between groups
No complaints of pain on injection reported
Higher incidence in level of sedation noted in placebo group
Not Significant
Apgar Scores
One Minute
Promethazine group range (7-9)
Placebo group range (6-9)
Five Minute
Promethazine group range (8-9)
Placebo group range (7-9)

33. Litchfield, J, Pronk C, Nezat G, Pellegrini JE
Litchfield, J, Pronk C, Nezat G, Pellegrini JE. Effect of 25 mg IM promethazine on the incidence and severity of PONV and pruritis in a cesarean section population receiving intrathecal morphine. Accepted AANA J 2009

34. Litchfield, J, Pronk C, Nezat G, Pellegrini JE
Litchfield, J, Pronk C, Nezat G, Pellegrini JE. Effect of 25 mg IM promethazine on the incidence and severity of PONV and pruritis in a cesarean section population receiving intrathecal morphine. Accepted AANA J 2009

35. Litchfield, J, Pronk C, Nezat G, Pellegrini JE
Litchfield, J, Pronk C, Nezat G, Pellegrini JE. Effect of 25 mg IM promethazine on the incidence and severity of PONV and pruritis in a cesarean section population receiving intrathecal morphine. Accepted AANA J 2009

36. Litchfield, J, Pronk C, Nezat G, Pellegrini JE
Litchfield, J, Pronk C, Nezat G, Pellegrini JE. Effect of 25 mg IM promethazine on the incidence and severity of PONV and pruritis in a cesarean section population receiving intrathecal morphine. Accepted AANA J 2009

37. Nausea Control Satisfaction
Litchfield J, Pronk C, Nezat G, Pellegrini JE. Effect of 25 mg IM promethazine on the incidence and severity of PONV
and pruritis in a cesarean section population receiving intrathecal morphine. Accepted AANA J

38. Pruritis Control Satisfaction
Litchfield J, Pronk C, Nezat G, Pellegrini JE. Effect of 25 mg IM promethazine on the incidence and severity of PONV
and pruritis in a cesarean section population receiving intrathecal morphine. Accepted AANA J

39. Conclusions
CSE is suggested method for analgesia in many OB anesthesia practices
PCEA reduces analgesic requirements and increases satisfaction in some studies
Basal infusion rates increase length of stage 2 labor but no adverse effects noted in relation to mode of delivery
PCEA with bolus can lead to higher incidence of cesarean section
Rapid infusion of oxytocin can result in significant hemodynamic instability
Extended release morphine shown to be safe and effective to use in cesarean section population
Prolonged duration of analgesia
Some concerns over prolonged side effect profile
Cannot use epidural catheter concomitantly with local anesthetic
Promethazine is viable option to prevent IT and epidural opioid induced side effects in a cesarean section population

40. Questions?