jc gerancher making pnb last a longtime
DESCRIPTION
this presentation reviews basic information on adjuncts to local anesthetics and peripheral nerve blockade. it was last undated and used for anesthesiology resident education in 2011. hope you find this information helpful. John Gerancher JC Gerancher MDTRANSCRIPT
Makingperipheral nerve
blocks work …for a really, really long
JC Gerancher MD
Professor and Section Head
Regional Anesthesia & Acute Pain Management
Medical Director of Surgical Services Informatics
Analgesia defined…
• Anesthesia• Motor block• Sensory block• “Analgesia= first request for additional
analgesia.”
Patient Satisfaction as an outcome of regional analgesia (not anesthesia)
• 7 of 10 RCT’s demonstrate improved patient satisfaction from post-op regional analgesia
• All of these 7 trials showed lower VAS pain scores
• None of 5 RCT’s demonstrate improved satisfaction from intra-op regional anesthesia
- Wu 2001
Local Anesthesia for PNB: No Free Lunch
Manufacturer’s Recommended Maximum Dose
(mg)
Mean Latency to Surgical Anesthesia (minutes)
Mean Durationof SurgicalAnesthesia
(hours)
Mean Duration of Postoperative
Analgesia (hours)
2-chloroprocaine(Nesacaine)
980 5-15 1-2 2-3
Lidocaine(Xylocaine)
490 7-15 2-3 3-5
Mepivacaine(Polocaine,Carbocaine)
400 10-15 3-4 4-6
Bupivacaine (Marcaine)
225 15-40 6-10 12-17
Ropivacaine(Naropin)
250 15-40 5-9 8-14
Local Anesthesia for PNB: No Free Lunch
Manufacturer’s Recommended Maximum Dose
(mg)
Mean Latency to Surgical Anesthesia (minutes)
Mean Durationof SurgicalAnesthesia
(hours)
Mean Duration of Postoperative
Analgesia (hours)
2-chloroprocaine(Nesacaine)
980 5-15 1-2 2-3
Lidocaine(Xylocaine)
490 7-15 2-3 3-5
Mepivacaine(Polocaine,Carbocaine)
400 10-15 3-4 4-6
Bupivacaine (Marcaine)
225 15-40 6-10 12-17
Ropivacaine(Naropin)
250 15-40 5-9 8-14
Mixtures for Supraclavicular block
0
5
10
15
20
25
Duration(hours)
latency(minutes)
2% lidocaine
0.5% bupivacaineplus epi
1% lido + 0.25%bupivacaine plusepi
-Bromage 1972
LA’s compared without epinephrine for fem-sciatic block
05
10152025303540
duration(hours)
latency(minutes)
2% mepivacaine
0.75% ropivacaine
0.5% bupivacaine
0.5% ropivacaine
0.5% levo-bupivacaine
-Casati 1998,2002
PNB Analgesia: Bupivacaine versus RopivacaineAuthor Type of PNB Equal dose? Epi used? Ropivacaine (hours) Bupivacaine (hours)
Junca Cervical Plexus R>B No 6 10Casati ISB R>B No 11 11Fanelli ISB R>B No 11 11Klein ISB R>B Yes 11 13Vaghadia SCB R>B No 11 12Bertini AXB Yes No 11 11Raeder AXB R>B No 12 13Liisanantti AXB Yes No 15 17Greengrass LPB-S Yes Yes 13 17McNamee F-S Yes No 13 15Fanelli F-S R>B No 11 14Connolly S R>B No 13 16
PNB LA choice and Analgesia
• Bupivacaine probably has a longer duration of analgesia
• You can’t make ropivacaine last longer by giving more of it
• Giving more than one drug probably makes sense.
• Local anesthetics choice is only one factor in the safe application of PNB.
• Is a very good idea• Positive effects
–Prolongs duration– Increases intensity–Reduces plasma levels (toxicity)–Marker of i.v. administration
Epinephrine in PNB
Increase in PNB duration (and maybe analgesia) with
epinephrine
0
20
40
60
80
100
Lido Mepiv Ropiv Bupiv
% increase inDuration
-Covino 1986, Weber 1999
33ml 0.5% Ropivacaine +/- Epi
- Hickey 1990
•Epino change in levels achieved with ropivacaine
•ropivacaine itself a vasoconstrictor
•Maybe why epi does not prolong ropivacaine block
Plasma Levels:
Duration
Clonidine for PNB
• Dose dependent prolongation of local anesthesia, analgesia
• Analgesia is independent of a systemic effect
• Mechanism: [alpha2]-Adrenoreceptor agonism, hyperpolarization-activated cation current.
© Karl Harrison, University of Oxford 2004
Clonidine analgesia for PNBAuthor Block Solution
Epi ?
Clonidine DoseControl
?Duration Without
Duration With
ReinhartAnkle (peds)
1.73% lidocaine No 140 mcg No 3 7
Singelyn AXB 1% mepivacaine Yes 0.5 mcg/ kg No 4 8
Iskandar Mid-H 1.5%mepivacaine No 50 mcg No 2 4
Casati AXB 0.75% ropivacaine No 1.0 mcg/kg No 13 15
Casati F-S 0.75% ropivacaine No 1.0 mcg/ kg No 14 17
El Saied AXB 0.75% ropivacaine No 150 mcg No 10 13
Hutschala AXB 0.25% bupivacaine Yes 2mcg/ kg Yes 1 7
Couture F-S 0.5% bupivacaine Yes 1.0 mcg/ kg No 12 12
Culebras ISB 0.5% bupivacaine Yes 150 mcg Yes 16 14
Clonidine analgesia for PNB• Prolongs shorter duration local anesthetics • 30-100 mcg is an effective dose • 30-100 mcg is unlikely to produce side effects• Clonidine may extend prolongation achieved
by epinephrine• Onset and quality of blockade is not impeded • Use with bupivacaine plus epinephrine?
‘Single Shot’: Proposed Maximal mean analgesia durations by
approach
02
46
810
1214
1618
CPB ISB SCB AXB POP F-S
First request foranalgesia (hrs)
Continuously Prolonged PNB: Is what we do usual?
• Exclusive use of stimulating catheters
• Inpatient infusions >> ambulatory infusions
• FNB > ICB > sciatic/popliteal >ISB
• ‘trifecta’ for TKA • All blocks done by CA-2 &-3’s
Dosing continuous PNB
• 0.2% ropivacaine and 0.25% bupivacaine at 0.1ml/kg/hr have been proven safe
• Unbound drug is the fraction of concern
• Little evidence for differential block
- Thomas 1999,Salonen 2000, Ekatodramis 2003
Continuous ISB
-Ilfeld 2004
No ‘clinically relevant improvements’ adding clonidine to cPNB?
• Worst and average VAS equal• Opioid consumption equal• Sleep disturbances equal• Side effects no different• Fewer patient controlled doses• More motor block from femoral cPNB• Are cPNB’s for chronic pain different?
-Ilfeld 2003, Capdevilla 2005
Continuous PNB Summary
• 0.2% ropivacaine has become most commonly used, but little studied
• Adjuncts probably have little utility• Basal rate of 7-10ml or 0.1ml/kg/hour• Patient controlled dosing popular
Impressive Multimodal Analgesia:COX-2 plus PCEA following TKA
Placebo Rofecoxib
PCEA requests (0-40 hours) 41 21Opioid consumption post PCEA 9 mg 6 mgVomiting 26% 6%VAS daily while in hospital 4 2VAS one week after discharge 4 3Degree flexion at discharge 73 84Degree flexion at one month 101 109
-Buvanendran, 2003
One dose of gabapentin for acute pain management:
Characteristics of studies
Number of studies found in the literature 22
Dose of gabapentin studied 300-1200mg
Degree of opioid sparing 20-62%
Mean 24 hour morphine sparing 30 mg
Numbers to treat (nausea) 25
Number to treat (vomiting) 6
Number to treat (urinary retention) 7
-Tiipana, 2007
-Gray 2006
U/S versus Nerve Stimulation
Technique Approach Block Time (min)
% ‘Success’
Onset Time (min)
Duration (min)
Williams2003
U/S+StimStim
SCB 510
8578
846652
Marhofer2004
U/SStim
ICB 100100
915
384310
Soeding2005
U/S+ “feel”“feel” alone
ISB andAXB
9590
672618
Liu2005
U/SU/SStim
122
678
839090
Where to Place Needles for the Best PNB technique:“Survey says..”
Where to Place Needles for the Best PNB technique:“Survey says..”