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Unformatted text preview: 2006 Update in 2006 Update in Obstetric Anesthesia: Part I Norman Bolden, M.D. August 8, 2006 Selected Topics and Excerpts From Selected Topics and Excerpts From 32 Annual Virginia Apgar Seminar nd Obstetric Anesthesia and Care of the Newborn March 19­21, 2006 Orlando, Florida Objectives 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. 2006 Update in OB Anesthesia 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……) CSE Kits/Needles 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) Incidence of Failure to obtain CSF 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 30­40% (Their technique was excellent­­­but their results were poor) Why is our success rate so low????? March 2006 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. Length of Spinal Needle for CSE very 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;97:574­7 24 g Sprotte (N = 36) 24 g Gertie Marx (N = 37) (120 mm long—protrudes 9 mm) ( 127 mm long­­­­protrudes 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) NB search: Espocan CSE needles NB search: Espocan CSE needles (Less failures, less paresthesias) 50 patients Espocan, 50 patients Conventional Epidural Tuohy + Gertie Marx spinal needle Espocan Conv Epid + 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;101:535­40 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. Review of Currently Available Review of Currently Available Options for CSEs at MHMC: MHMC CSE Options 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. Durasafe CSE needles with Durasafe CSE needles with different whitacre needles Durasafe CSE needles with Durasafe CSE needles with different 25 g Whitacres 25 g Pencan thru 18g Braun Tuohy 25 g Pencan thru 18g Braun Tuohy (our usual Epidural needle) 25 g Espocan CSE Needle 25 g Espocan CSE Needle 25 g Espocan Epidural and 25 g Espocan Epidural and Spinal needle with sheath What about CSE for the 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!” 13 cm Gertie Marx vs. 9 cm Espocan 13 cm Gertie Marx vs. 9 cm Espocan (Arnie’s “Biggie Size” Needle) Gertie Marx CSE for the Obese Gertie Marx CSE for the Obese Needle is very flimsy Wings on needle easily come off Epidural space often encountered 9.5­12 cm in obese patients so regular CSE needles ineffective even with indenting skin. 25 g Pencan thru Durasafe Epidural needle 25 g Pencan thru Durasafe Epidural needle (Whoa­­­­careful 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) MHMC CSE Series since MHMC CSE Series since March 2006 Pencan thru Durasafe needle (20mm) Success: Paresthesias: 4 of 4 (no failures) 1 of 4 (25%) Success: Paresthesias: 27 of 30 5 of 30 (17%) Espocan CSE Needles (15mm): 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 Failure to obtain CSF thru spinal 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 CSE Failures CSE Failures Tenting of Dura by Needle Tenting of Dura by Needle Why all the fuss with CSEs? Are they worth the Why all the fuss with CSEs? Are they worth the H/A­­­­and by the way, are there more H/As with CSEs? Many large academic centers perform 75­90% 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. Labor CSE Advantages: Rapid onset of effective labor analgesia. 2­3 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 ? Improved success of epidurals as ? 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: 913­29 Labor CSE Advantages: Rapid onset of effective labor analgesia. 2­3 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 CSE and progress of labor CSE and progress of labor Is combined spinal­epidural 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 P655­665 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) Labor CSE Advantages: Rapid onset of effective labor analgesia. 2­3 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) Labor CSE Disadvantages: 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 Respiratory Depression and Respiratory Depression and CSEs Reference Doses of IT narcotics for Reference Doses of IT narcotics for labor Previous Doses Sufentanil 10­15 mcg Fentanyl 50 mcg Current Doses Sufentanil 2.5­5 mcg Fentanyl 15­25 mcg Labor CSE Disadvantages: 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 Status of Epidural not known 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 1.5­2 hours) Labor CSE Disadvantages: 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 CSE and Fetal Bradycardia 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 Risk Factors for Fetal Decelerations 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, 208­211 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. Intrathecal Sufentanil and Fetal Heart Rate Abnormalities: A Double­Blind, Double Placebo­Controlled Trial comparing Two Forms of Combined Spinal Epidural Analgesia with Epidural Analgesia in Labor Van de Velde et al, Anesth Analg 2004;98:1153­9 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 (Within first hour of initiation) Group 1: Group 2: Group 3: 12% 24% Uterine Hyperactivity Groups 1 & 2 Group 3 2% 22% Hypotension (Requiring Ephedrine) Group 1 Group 2 Group 3 7% 29% ( 12% 11% Bupi) CSE and Fetal Bradycardia CSE and Fetal Bradycardia Summary 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. Temporarily Changing 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! Nitroglycerin: Tocolysis now! Nitroglycerin: Tocolysis now! The precise mechanism by which NTG causes uterine relaxation (tocolysis) remains unclear Ususal dosage 100­500 mcg IV, 400­800mcg SL (1­2 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 Nitroglycerin: Tocolysis 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!) Nitroglycerin as Rx CSE associated Nitroglycerin as Rx CSE associated Fetal Decelerations Small doses of I.V. Nitroglycerine (60­180 mcg) are associated with resolution of severe fetal distress related to uterine hyperactivity along with negligible side effects. Mercier et al, Anesth Anal 1997;84:1117­1120 Labor CSE Disadvantages: 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 Labor CSEs are more costly Labor CSEs Current Braun Perifix Epidural Tray: Pencan Needle Individual Durasafe CSE Kit (Needles Only) Individual Espocan CSE Kit (Needles Only) $ 5.25 $ 9.00 $15.50 (Prepacked $7.03 or 45% less) Braun Kit with Espocan CSE Needle added: $17.97 (Add’l $7.03 or 39%) $25.00 (We will soon have a large stock of our current Braun/Perfix Epidural kits, and have a smaller supply of epidural trays prepackaged with the Espocan Needle) Labor CSE Disadvantages: 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 Higher incidence of “Paresthesias/Pain” during Higher incidence of “Paresthesias/Pain” during spinal advancement with CSE than with single shot spinals 89 woman for elective C/S randomized to single shot spinal or needle thru needle spinal (CSE). Paresthesias in 37% needle thru needle Paresthesias in 9% single shot spinal No patients had persistent neurological symptoms on postop day #1 McCandrew CR­ Anaesth Intensive Care – 01­Oct­2003: 31(5): 514­7 Epidural lidocaine decreases Epidural lidocaine decreases paresthesias/pain associated with dural puncture during CSEs 3cc 2% Xylocaine with 1:200 K epi (vs. saline) given via Tuohy needle after LOR, and then spinal needle advanced. Pain/Paresthesias in Lidocaine Group 9 % Pain/Paresthesias in Saline Group 81% Van den Berg et al, Anesth Analg 2005: 101: 882­5 Note: This should NOT be done for labor CSEs! When should the epidural test dose When should the epidural test dose be administered with CSE? Administering the 3cc test dose of 1.5% Xylo with epi immediately after the labor CSE leads to an increased incidence of hypotension (spinal Bup + Epidural Xylo) and leads to undesired (excessive) motor block Options include: 1. Administer epidural test dose after spinal dose wears off. 2. Start Continuous Infusion immediately after CSE performed CSE test dose options CSE test dose options (Continued—Option 1) Test dose administered prior to dosing epidural. Very labor intensive as one must monitor VS after spinal dose, and then return (1.5 – 2 hours) to administer test dose and epidural bolus and monitor VS. Pain allowed to return so less patient satisfaction. Not Resident/CRNA friendly overnight during calls. CSE test dose options CSE test dose options (Continued­­­Option 2) One can immediately start the continuous infusion after spinal dose given Experience > 5 years Rationale: If intravascular, patient will c/o pain. Can test catheter at that time prior to epid re­bolus, and if +, pull catheter. Low dose of Bupivicaine administered so very low possibility of toxicity (~ 10 mg of Bupivicaine in an hour vs. toxic dose of 150mg) If intrathecal cath, patient will slowly develop motor block and hypotension (10 mg Bupi in an hour). Patients instructed to call nurse for increased motor block and/or hypotension and we must follow up on patients. Anesthesia “friendly”, patients more satisfied as pain doesn’t return and anesthesia personnel don’t have to stay and check VS for two prolonged periods. What the heck is in our What the heck is in our CSE cocktail anyway???? (I’d put my money on the residents over the attendings) (gift certificate) MHMC CSE “Cocktail” MHMC CSE “Cocktail” Fentanyl 15 mcg Bupivicaine 1.25 mg Epinephrine .1 mg (Do we really need this?­­­not used in NEJM study) (Is there a downside to epi?) Saline diluent to make total volume 3cc LAs added to CSE solutions LAs added to CSE solutions Intrathecal narcotics alone can produce effective relief of labor pain for the first stage of labor Intrathecal narcotics alone are ineffective in relieving pain associated with the 2nd stage of labor LAs (bupivicaine) combined with spinal narcotics provide effective relief of pain associated with the second stage of labor Patients receiving bupivicaine added to spinal narcotics often report better relief of perineal pain/pressure throughout labor, and also require fewer physician administered top up doses. What about the downside to adding epi? Epinephrine in CSE solutions Epinephrine in CSE solutions Prolongs duration of block/pain relief from intrathecal narcotic + LA solutions for labor pain relief Produces additional motor block, compared to solutions without epinephrine Goal in OB anesthesia to have as little motor block as possible, while maintaining satisfactory pain relief Though epinephrine is associated with additional motor block, this motor block is minimal, and most patients are still able to “walk” after a CSE with Bupivicaine. But why would they want to?????? NB Suggestions for labor CSEs NB Suggestions for labor CSEs 1. 2. 3. Use CSE needle that protrudes 15 mm beyond the Epidural needle (preferably with a low incidence of paresthesias) Currently suggest Espocan at MHMC Do NOT perform CSE technique in patients with bad fetal tracings or patients expected to go to the OR soon. You will have a higher incidence of fetal bradycardias in the setting of bad tracings and you will not know if epidural catheter works immediatley following the CSE. Advance Espocan needle slowly thru epidural needle (to decrease paresthesias) and first LOR is subarachnoid space. 4.. 4 5. 6. 7. 8. Stabilize spinal needle. It WILL move! If no CSF obtained, withdraw spinal needle and advance epidural needle 1 mm. Reinsert spinal needle. If no CSF, thread epidural catheter, give test dose and bolus. (Remember, ~ 10% incidence of failure to get CSF) Inject 15 mcg Fentanyl, 1.25 mg Bupivicaine (less n/v/itching/respiratory depression and less hypotension) Do NOT administer the 3cc Xylocaine (1.5%) epidural test dose immediately after spinal dose as this will increase incidence of hypotension and lead to unwanted motor block. 9.. 9 After spinal dose administered, two options: A. Wait > 1 hour to administer Epidural test dose and bolus epidural 1. 2. B. Pain will return Anesthesia personnel labor intensive Start continuous epidural infusion immediately 1. 2. 3. 4. Notify patient if legs become very heavy to contact nurse as patient may be receiving too much medication Do not place patients on PCEA who have a language barrier or who cannot comprehend nuances of PCEA. Greater patient satisfaction Less labor intensive­­­less physician administered top up dosed. 10. 10. 11. If Hypotension develops RX with Neosynephrine or Ephedrine If Fetal Decelerations are noted: A. B. C. LUD, Oxygen, Rx BP (even if BP is marginal rx BP to eliminate this as a variable) 2 metered sprays of sublingual Nitroglycerin Decelerations should resolve in 5­10 minutes. If patient taken to OR, prepare for urgent C/S. Patient Controlled Epidural Patient Controlled Epidural Analgesia (PCEA) Overall greater patient satisfaction with PCEA vs. continuous infusion Lower drug usage with PCEA (no basal rate) vs. continuous infusion PCEA with basal rate is associated with 30% more drug usage compared with PCEA and no basal rate. PCEA with basal rate associated with decreased physician “top­ups”. Only physician administered “top­ups” associated with hypotension. PCEA PCEA Majority of academic tertiary care facilities routinely utilize PCEA for labor pain relief When new epidural pumps obtained, we will routinely use PCEA at MHMC. Current pumps have few patient administration buttons, and therefore, difficult to consistently employ PCEA. MHMC PCEA Settings (Various centers polled last year by Drs. Bolden/Lahud): Basal 8­10 cc/hr. Bolus 5cc # Boluses/hr =4. Lockout = 10 minutes Confused? Confused? I hope to eliminate some of the confusion……. We will primarily be ordering espocan CSE needles for non­ obese patients, and retain Long Gertie Marx CSE kits for the obese patient. We will stop ordering the durasafe CSE kits. I am sure some attendings would have objected, so I wanted everyone to know the reason/rationale for this change. When we obtain new PCEA pumps, we will be using PCEA on the majority of our patients (except those patients with a language barrier or those unable to comprehend the instructions) Stay tuned for more exciting topics in the world of OB Anesthesia in “2006 Update in Obstetric Anesthesia­­ Part II” ...
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This note was uploaded on 12/16/2011 for the course BIOLOGY 101 taught by Professor Mr.wallace during the Fall '11 term at Montgomery College.

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