Effectiveness and safety of CPNB and continuous local wound infusion Basal infusion with PCA option Types of pumps – elastomeric vs. electronic Outpatient and home infusion pumps

1. CONTINUOUS PUMP DELIVERY SYSTEMS
IN PAIN MANAGEMENT
Dr Ho Kok Yuen
MBBS, MMed (Anaes), FIPP, DAAPM
Consultant Anaesthesiologist
President, Pain Association of Singapore
Clinical Director, Pain Management Service, Raffles Hospital

2. Early Indications
• Prolonging intraoperative surgical anaesthesia
• Sympathectomy and vasodilation to increase
blood flow
– Limb salvage
– Digital replantation
– Raynaud’s disease
• Chronic pain
– CRPS
– Phantom pain

3. Indications for Continuous Pump
Delivery Systems
• Continuous peripheral nerve blocks
– Perioperative analgesia
– Postoperative analgesia
– CRPS
– Phantom pain
• Continuous intrathecal/epidural infusions
– Cancer pain

4. Continuous Peripheral Nerve Blocks
(CPNB)
• Brachial plexus
– Interscalene
– Infraclavicular
– Axillary
• Lumbar plexus
– Femoral nerve sheath
– Psoas compartment
• Sciatica nerve

5. Nerve stimulation technique

6. Ultrasound-Guided

7. Ultrasound Guidance Improves
Efficacy of PNB
• Higher rate of successful blocks
• Less time to perform, less discomfort
• Faster onset (29% shorter onset time)
• Longer duration (25% longer)
• Reduced risk of vascular puncture
Abrahams MS, et al. Br J Anaesth 2009;102:408-17

8. Advantages of Continuous
Peripheral Nerve Block
• Improved pain control during mobilisation
• Decrease opioid use
• Less nausea, vomiting, pruritus and sedation
• Greater patient satisfaction
• Improved functional outcomes
• Outpatient use
Capdevila X, et al. Anesthesiology 1999;91:8-15
Richman JM, et al. Anesth Analg 2006;102:248-57
Bingham AE, et al. Reg Anesth Pain Med 2012

9. 1. 19 RCT’s (11 double-blind)
2. Better analgesia for all time periods at 24, 48 and 72 h and all
catheters
3. Reduction in opioid use
4. Lower incidence of PONV (21 % vs. 49 %), sedation (27% vs.
52%), and pruritus (10 vs. 27 %) with PNB´s
5. Improved patient satisfaction (4 RCT’s only)
6. CPNB, regardless of catheter location, provided superior
postoperative analgesia and fewer opioid-related side effects
when compared with opioid analgesia
Anesth Analg 2006;102:248-57
Richman JM, et al. Anesth Analg 2006;102:248-57

10. Drugs
Local Anaesthetics
• Bupivacaine, levo-bupivacaine and ropivacaine
– Cardiotoxicity ratio 3: 1.7: 1
– Ropivacaine: less motor block
• Common concentrations:
– Bupivacaine or L-bupivacaine 0.1-0.25%
– Ropivacaine 0.2%

11. Drugs
Adjuvants
• Unknown analgesic combination for optimal
pain relief
• E.g. adrenaline, clonidine, opioid

12. Clonidine
• Meta-analysis of 20 RCTs
• Prolongs analgesia and sensory by about 2 hrs
• Increases risk of hypotension, fainting,
bradycardia and sedation
• Prolongs motor block
Popping DM, et al. Anesthesiology 2009;111:406-15

13. Determinants of CPNB Effect
• Dose (mass)
• Volume (rate)
• Concentration

14. Infusion Strategies
• Continuous infusion
– Greater use of LA
– May produce dense block
• Infusion with patient-controlled (PCA) boluses
– Comparable analgesia
– 30% less LA
• Patient-controlled (PCA) boluses only
– Higher pain scores
– Greater opioid consumption

15. Taboada M, et al. Anesth Analg 2008;107:1433-7

16. Figure 1. Box plots of verbal rating pain scores (VRS) obtained from the two groups at 6, 8,
12, and 24 h postoperatively.
Taboada M et al. Anesth Analg 2008;107:1433-1437

17. Taboada M, et al. Anaesthesiology 2009;110:150-4
• 50 patients randomized to 0.125% levobupivacaine
infusion administered through a popliteal catheter as
an automated regular bolus or as CI, both combined
with PCA
• Both dosing regimens - similar postop analgesia
• Consumption of LA and dose request from the PCA
lower in the automated bolus group

18. 60 patients received ISB:
Gp 1: CI of 0.125% bupivacaine with sufentanil 0.1 microg/mL and
clonidine 1 microg/mL at 10 mL /h
Gp 2: 5 mL/h plus PCA boluses
Gp 3: only PCA boluses
Sensory block more frequent and pain control was significantly higher in
Groups 1 and 2 than in Group 3 (P < 0.01).
A basal infusion of 5 mL/h combined with PCA boluses most appropriate
Singelyn FJ, et al. Anesth Analg 1999;89:1216-20

20. 0.2% ropivacaine delivered as
a CI combined with PCA bolus
doses via an infraclavicular
perineural catheter optimizes
analgesia while minimizing
oral analgesic use compared
with basal- or bolus only
dosing regimens.

21. Intermittent Bolus Superior?
• Intermittent bolus
– higher pressure and more volume per time
– may increase spread of LA in the popliteal fossa,
thus reaching the two trunks of the sciatic nerve
more easily
• Intermittent bolus doses may reach the
targeted nerve before they are taken up by
perineural tissue or removed by blood vessels

22. Advantage of PCA bolus
• Decreasing basal infusion rate and
theoretically decreasing motor block
• Decreasing incidence of insensate extremity
• Increasing duration of infusion/analgesia for
ambulatory patients discharged with a finite
volume of LA
Borgeat A, et al. Anesth Analg 2001;92:218-23
Ilfeld BM et al. Anesthesiology 2002;97:959-65
Ilfeld BM, et al. Anesthesiology 2004;101;970-7

23. Optimal Infusion Regimen
• Basal rate 4-10 ml/h
– Lower rates for catheters of the lower extremity
– Higher rates for catheters of the upper extremity
• Bolus volume 2-10 ml
• Bolus lockout period 20-60 minutes

25. Elastomeric Pumps
• Lightweight, portable
• Simple to set up
• Disposable
• Overinfusion
– Initial 3-6 hrs
– Near reservoir exhaustion
• Infusion rate increases with
increasing ambient temp
and pump height
Ilfeld BM, et al. RAPM 2003;28:424-32

26. Outpatient/Home Continuous
Pump Infusions
• Advantages
– Shortens hospital stay
– Early discharge
– Good pain control at home

27. Outpatient/Home Continuous
Pump Infusions
• Problems with nerve catheters
– Accidental dislodgement
– Excessive leakage at insertion site
– Infection
– Neurological injury

28. Electronic Infusion Pumps
• Accurate and consistent
infusion rates
• Adjustable infusion rate
• Has PCA function
• Variable bolus lockout
period
• Limited to inpatient use
Ilfeld BM, et al. RAPM 2003;28:424-32

29. Incisional Catheters
• Simple, safe, inexpensive
• Catheter placed at correct position under direct vision
• Eliminates risk of inadvertent penetration of vascular or neural structures
(vs. perineural)
• Only area of surgery affected allowing normal use of extremity and early
rehabilitation (vs. perineural)
• Useful for ambulatory and inpatient surgery
Liu, Kehlet

31. Lower Pain Scores

32. Less Opioid Consumed

33. Continuous Wound Infusion
• 58 patients undergoing LSCS
• Randomized to:
– Wound infusion with ropivacaine 0.2% at 5ml/h
– Epidural morphine 2mg 12H
• Better analgesia at 24 and 48 hrs, less nausea,
vomiting, pruritus and urinary retention
O’Neill P, et al. Anesth Analg 2012;114:179-85

34. Summary
• Effectiveness and safety of CPNB and
continuous local wound infusion
• Basal infusion with PCA option
• Types of pumps – elastomeric vs. electronic
• Outpatient and home infusion pumps