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2006 Update in Obstetric Anesthesia: Part I

2006 Update in Obstetric Anesthesia: Part I. Norman Bolden, M.D. August 8, 2006. Selected Topics and Excerpts From 32 nd Annual Virginia Apgar Seminar Obstetric Anesthesia and Care of the Newborn March 19-21, 2006 Orlando, Florida. Objectives.

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2006 Update in Obstetric Anesthesia: Part I

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  1. 2006 Update in Obstetric Anesthesia: Part I Norman Bolden, M.D. August 8, 2006

  2. Selected Topics and Excerpts From 32nd AnnualVirginia Apgar SeminarObstetric Anesthesia andCare of the NewbornMarch 19-21, 2006Orlando, Florida

  3. Objectives • Expose staff to current practices and trends in the area of Obstetric Anesthesia • Share practical applications related to these topics that can be incorporated into our routine practice at MHMC • Compare/contrast our practices with those of other tertiary care facilities • Give references for various topics • Time will not permit critical review of all references and this will NOT be attempted.

  4. 2006 Update in OB Anesthesia • Part I: CSE and PCEA • Part II: All other topics in OB Anesthesia • More diverse and interesting topics (Date to be announced……)

  5. CSE Kits/Needles • Why so many choices?? (We currently have 5 different kits or combinations of CSE needles at MHMC ----enough is enough!) • What would make one CSE needle better or more effective than another? • Aren’t all 25 g needles created equal? • Why do we fail to get the CSF when we want to during CSEs, (and far too often get the gusher when we don’t want to see it!---during regular epidurals)

  6. Incidence of Failure to obtain CSF during CSE Most commonly quoted figure of failed CSEs (failure to obtain CSF during CSE): Reported incidence 10% Reported incidence varies from 8%-38% depending on needles used • MHMC Feb 2006 Woodring and Sheth, incidence of failure to get CSF 30-40% (Their technique was excellent---but their results were poor) • Why is our success rate so low?????

  7. March 2006 Virginia Apgar Obstetric Anesthesia Conference, Orlando FL • Spinal needle must protrude 15 mm beyond epidural needle to have high likelihood for success in obtaining CSF! • Length of spinal needle alone cannot be used as sole determinant as to if spinal needle is long enough for CSE success with a given epidural needle. • Hubs of spinal needles inserted thru Tuohys varies considerably with manufacturer. You must actually measure to make sure that your spinal needle protrudes 15 mm beyond your epidural needle.

  8. Length of Spinal Needle for CSE very important (as is the hub)! • A comparison of 24 g Sprotte and Gertie Marx Spinal Needles for CSE during labor Riley et al, Anesthesiology, 2002;97:574-7 24 g Sprotte (N = 36) 24 g GertieMarx (N = 37) (120 mm long—protrudes 9 mm) ( 127 mm long----protrudes 17mm) No CSF *6/36 (17%) 0/37 *(In all 6 cases where the sprotte needle did not produce CSF, the longer Gertie Marx needle was inserted and CSF was obtained)

  9. NB search: Espocan CSE needles(Less failures, less paresthesias) • 50 patients Espocan, 50 patients Conventional Epidural Tuohy + Gertie Marx spinal needle Espocan ConvEpid + Gertie Marx • Intravascular Catheter 2% 6% • Paresthesia (or Pain) 14%42% • Wet tap 2% 2% • Failure to obtain CSF 8%28% • Intrathecal Cath Placement 0% 0% • Brown, Birnbach, Stein et al Anesth Analg 2005;101:535-40

  10. Our success rate was lower than expected because our CSE needles were too short! Most of our CSE needles only protruded 13 mm beyond the epidural needle, rather than the recommended 15 mm.

  11. Review of Currently Available Options for CSEs at MHMC:

  12. MHMC CSE Options • Please take a look at the two trays being passed around, each with various CSE needles. • Please feel the resistance with Pencan thru conventional Tuohy, vs. no resistance with Espocan CSE set. This will take some getting used to.

  13. Durasafe CSE needles with different whitacre needles

  14. Durasafe CSE needles with different 25 g Whitacres

  15. 25 g Pencan thru 18g Braun Tuohy (our usual Epidural needle)

  16. 25 g Espocan CSE Needle

  17. 25 g Espocan Epidural and Spinal needle with sheath

  18. What about CSE for the Obese??? • Most CSE kits packaged with only 9 cm Tuohy • At OB conference, I asked what do others do when they want to do a CSE in the really obese (many MHMC patients) • 3 from panel said they just don’t do them as needles not long enough. • One panelist said “Biggie size it with Gertie Marx!”

  19. 13 cm Gertie Marx vs. 9 cm Espocan (Arnie’s “Biggie Size” Needle)

  20. Gertie Marx CSE for the Obese • Needle is very flimsy • Wings on needle easily come off • Epidural space often encountered 9.5-12 cm in obese patients so regular CSE needles ineffective even with indenting skin.

  21. 25 g Pencan thru Durasafe Epidural needle (Whoa----careful now!) • For those that don’t like the espocan, but want to increase success rate • Extends 20 mm • Very wasteful (Braun epidural kit, Durasafe CSE needle, Pencan needle)

  22. MHMC CSE Series since March 2006 • Pencan thru Durasafe needle (20mm) • Success: 4 of 4 (no failures) • Paresthesias: 1 of 4 (25%) • Espocan CSE Needles (15mm): • Success: 27 of 30 • Paresthesias: 5 of 30 (17%) Since routinely utilizing spinal needles which protrude at least 15 mm beyond the epidural needle, we have had greater success with the CSE technique, and our success rate now mirrors that reported by others with high success rates. (Currently failure to obtain CSF in 10%)

  23. Failure to obtain CSF thru spinal needle during CSE: Explanations • Needle too short (Recommend 15 mm protrusion of spinal thru epidural needle) • Needle off midline • Tenting of Dura

  24. CSE Failures

  25. Tenting of Dura by Needle

  26. Why all the fuss with CSEs? Are they worth the H/A----and by the way, are there more H/As with CSEs? • Many large academic centers perform 75-90% CSEs for labor pain relief • MHMC performs ~ 15% CSEs for labor • Last week of every OB rotation consists of ALL CSEs. This provides residents with exposure to technique, and allows them to form their own opinions about the technique.

  27. Labor CSE Advantages: • Rapid onset of effective labor analgesia. 2-3 mins vs. ~ 15 minutes with conventional epidurals • Less LA and opioid required • Less motor block. Allows for “walking epidurals”. • ? Improved success of subsequent epidural (probably NOT!)---let’s look at this…… • May speed progress of labor • Greater patient satisfaction

  28. ? Improved success of epidurals as part of CSE • Failure to get CSF in ~ 10% of cases (Higher failure rate if spinal needle not long enough) • Randomized study1 of 2183 patients receiving either CSE or a standard epidural found no significant difference of successful epidural between the two groups. • 1Norris MC< et al: Anesthesiology 2001: 95: 913-29

  29. Labor CSE Advantages: • Rapid onset of effective labor analgesia. 2-3 mins vs. ~ 15 minutes with conventional epidurals • Less LA and opioid required • Less motor block. Allows for “walking epidurals”. • ? Improved success of subsequent epidural (probably NOT!) • May speed progress of labor—let’s look at this… • Greater patient satisfaction

  30. CSE and progress of labor • Is combined spinal-epidural Analgesia Associated with more Rapid Cervical Dilation in Nulliparous Patients when Compaired with Conventional Epidural Analgesia? Tsen et al Anesthesiology 91: No 4, Oct 1999 Cervical Dilation (after 3 cm) N=100 (50 each group) CSE mean dilation 2.1 +/- 2.1 cm/hr , Epid mean dilation 1.1 +/- 1 cm/hr (5 pts had initial dilation > 5cm/h in CSE group, none in Epid) • The Risk of Cesarean Delivery with Neuraxial Analgesia Given Early versus Late in Labor Wong et al, NEJM Feb 2005 Vol 352. No 7 P655-665 No difference in C/S rate Median time from initiation to complete dilation significantly shorter after intrathecal analgesia than systemic analgesia (295 minutes vs. 385 minutes P < 0.001)

  31. Labor CSE Advantages: • Rapid onset of effective labor analgesia. 2-3 mins vs. ~ 15 minutes with conventional epidurals • Less LA and opioid required • Less motor block. Allows for “walking epidurals”. • ? Improved success of subsequent epidural (probably NOT!) • May speed progress of labor • Greater patient satisfaction (Higher satisfaction with CSE vs. Conventional, but high with both)

  32. Labor CSE Disadvantages: • Pruritus, N/V (Mild symptoms and less frequent with smaller doses). • Respiratory Depression (Rare with doses) • ? Increase in PDPH (NOT!) • ? Increase in intrathecal catheters (NOT!) • Fetal Decelerations • Untested Epidural • More costly • Paresthesia/Pain during spinal insertion

  33. Respiratory Depression and CSEs

  34. Reference Doses of IT narcotics for labor • Previous Doses • Sufentanil 10-15 mcg • Fentanyl 50 mcg • Current Doses • Sufentanil 2.5-5 mcg • Fentanyl 15-25 mcg

  35. Labor CSE Disadvantages: • Pruritis, N/V (Mild symptoms and less frequent with smaller doses). • Respiratory Depression (Rare with doses) • ? Increase in PDPH (NOT!) • ? Increase in intrathecal catheters (NOT!) • Untested Epidural • Fetal Decelerations • More costly • Paresthesia/Pain during spinal insertion

  36. Status of Epidural not known • We like to have functioning epidurals. If the epidural is not working properly, we suggest early replacement • Epidural not immediately dosed after CSE so there is no way to know if epidural will function for an urgent C/S. • Epidural test dose not initially performed as this additional LA would lead to increased incidence of hypotension and unwanted excessive motor block. (This potentially makes the CSE more labor intensive if personnel must return to “test” the catheter and administer the epidural bolus (usually after 1.5-2 hours)

  37. Labor CSE Disadvantages: • Pruritis, N/V (Mild symptoms and less frequent with smaller doses). • Respiratory Depression (Rare with doses) • ? Increase in PDPH (NOT!) • ? Increase in intrathecal catheters (NOT!) • Untested Epidural • Fetal Decelerations • More costly

  38. CSE and Fetal Bradycardia • Numerous reports documenting severe bradycardia after IT fentanyl or sufentanil sometimes in association with documented uterine hypertonus. • Proposed mechanism: rapid onset of analgesia with IT opioids causes acute decrease in catecholamines, especially epi, which is tocolytic. The resulting disinhibition may cause increased uterine tone with subsequent placental ischemia and fetal bradycardia. • Though FHR abnormalities usually resolve, one must always be prepared for urgent C/S.

  39. Risk Factors for Fetal Decelerations following CSE for labor • Predicting prolonged fetal heart rate deleration following intrathecal fentanyl/bupivicaine Gaiser et al, International Journal of Obstetric Anesthesia (IJOA) (2005) Vol 14, 208-211 33/151 patients (21%) had fetal decelerations (mean 4.1 minutes) following CSE for labor. None of these patients underwent C/S. Lack of fetal engagement (zero station) (odds ratio 5.5) and presence of heart rate decelerations within 30 minutes prior to CSE (odds ratio 3.6) were associated with prolonged fetal heart rate decelerations after CSE.

  40. Intrathecal Sufentanil and Fetal Heart Rate Abnormalities: A Double-Blind, Double Placebo-Controlled Trial comparing Two Forms of Combined Spinal Epidural Analgesia with Epidural Analgesia in Labor Van de Velde et al, Anesth Analg 2004;98:1153-9 Three Hundred Paturients randomized to three groups: Group 1: Epidural with 12.5 mg Bupivicaine, 12.5 mcg Epi, 7.5 mcg Sufentanil Group 2: CSE with Sufentanil 1.5 mcg, Epi 2.5 mcg, and Bupivicaine 2.5 mg Group 3: CSE with Sufentanil 7.5 mcg Fetal Decels Group 1: 11% (Within first hour of initiation) Group 2: 12% Group 3: 24% Uterine Hyperactivity Groups 1 & 2 2% Group 3 22% HypotensionGroup 1 7% (Requiring Ephedrine) Group 2 29% ( Bupi) Group 3 12%

  41. CSE and Fetal BradycardiaSummary by Dr. Richard Smiley (Virginia Apgar Conference Mar 2006) • Fairly clear that incidence of fetal heart rate abnormalities is similar between CSE and most epidural techniques (though time course is different—more rapid with CSEs) • Cesarean sections are NOT more common with CSE analgesia (if OB’s are “trained”) • More recent randomized series suggest bradycardias are associated with higher doses of opioids than generally used today, with lower dose opioid/LA mixtures resulting in same incidence as standard epidurals.

  42. Temporarily Changing Course….. • Hang in there while I cover this related topic. • We will return to the pros and cons of CSEs shortly……. • What can be done if the fetal decelerations after CSE are in fact due to increased uterine tone????? ---NTG may be the answer!

  43. Nitroglycerin: Tocolysis now! • The precise mechanism by which NTG causes uterine relaxation (tocolysis) remains unclear • Ususal dosage 100-500 mcg IV, 400-800mcg SL (1-2 metered sprays)---(published reports from 50 mcg-1850 mcg) • Relaxation of the uterus is typically reported within 90 seconds • ASA Task Force on OB Anesthesia: Practice guidelines for OB Anesthesia Recommends NTG as effective agent for uterine relaxation for retained placenta tissue

  44. Nitroglycerin: Tocolysis(Uses) • Retained Placenta • Internal and External Versions • Entrapped Fetuses at Vaginal Delivery and Cesarean Section • Fetal Surgery • *Fetal Distress (Bradycardia) associated with hyperstimulation or tetany (whether or not caused or associated with CSE!)

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