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Peripheral nerve catheter techniques
TECHNICAL SKILLS
Peripheral nerve catheter techniques
Learning objectives After reading this article, you should be able to: C understand the benefits and side-effects of peripheral nerve catheters C describe the different methods of catheter insertion C be aware of the relationship between anaesthetic concentration, pain relief and motor block.
Graeme McLeod
Abstract Peripheral nerve catheter techniques provide pain relief on movement for upper and lower limb arthroplasty and amputation. The optimal perineural concentration and volume of ropivacaine and levobupivacaine are not known for upper or lower limb block. The most common complication associated with perineural infusion is infection and, thus, aseptic technique is necessary for both insertion of catheters and use of elastomeric balls. Compared with parenteral opioids, perineural infusion of local anaesthetic accelerates rehabilitation and reduces hospital length of stay. However, little evidence exists regarding surgical outcomes, particularly those concerned with functional wellbeing.
the nerve is confirmed by injection of 1 ml increments of local anaesthetic and spread readily seen. Injection of 5 ml aliquots of solution forms a hydrospace around the nerve and creates a space for catheter insertion. Catheter insertion is relatively straightforward in the lower limb, as the catheter is threaded easily, whereas in the upper limb placement is more difficult, and insertion length limited to approximately 5 cm. Catheter position may be confirmed with ultrasound by eliciting movement of the catheter, or spread of further local anaesthetic. Alternatively, stimulating catheters may be used to locate peripheral nerves. This device has a wire placed within its wall, allowing continued nerve stimulation after catheter insertion to optimize placement. Although studies have shown faster surgical block, and a sparing effect on rescue medication, stimulating catheters are not associated with a decrease in side-effects. Realistically, they take more time to place, and have been superseded by direct ultrasound imaging.4
Keywords Arthroplasty; catheter; levobupivacaine; outcome; perineural; pharmacodynamics; ropivacaine
Benefits The principal benefit of perineural infusion of local anaesthetic is extended pain relief into the second and third postoperative days. After lower limb surgery, pain relief is better than patientcontrolled analgesia1 and similar to epidural analgesia after major limb surgery, albeit with reduced opioid-related sideeffects.2 For amputation, continuous pain relief is possible for 1e2 weeks if necessary. Motor block invariably occurs after continuous infusion of commercial preparations of local anaesthetics, but is reduced by using lower concentrations of levobupivacaine3 or ropivacaine, while still maintaining pain relief.
Pharmacodynamics The optimal perineural concentration and volume of ropivacaine and levobupivacaine are not known for upper or lower limb block. As such, there has been a tendency to use the same concentrations of local anaesthetics investigated in epidural block studies. However, a recent trial designed to prevent pain up to 36 hours after knee arthroplasty has shown that the EC50 of femoral levobupivacaine is 0.024%.3 The doseeresponse curves of levobupivacaine and ropivacaine have yet to be determined.
Technical aspects Perineural catheters may be positioned either surgically or percutaneously (see Figure 1). Surgical intervention typically occurs when placing a sciatic catheter during above-knee amputation, with percutaneous tunnelling to the lateral aspect of the thigh. By contrast, anaesthetists identify peripheral nerves using either nerve stimulation or ultrasound, although a combined procedure is often used by inexperienced anaesthetists to verify nerve location. For ultrasound-guided block, a 50 mm or 100 mm Tuohy needle is introduced through the skin and advanced towards the nerve. When inserted out of plane to the ultrasound probe, a needle track can often be seen, whereas when inserted in plane the needle may be visible. Proximity to
Graeme McLeod PGCertMedEd MD MRCGP FRCA FFPMRCA is a Consultant & Honorary Reader in Anaesthesia, University Department of Anaesthesia and Clinical Lead for Anaesthetic Research, Ninewells Hospital & Medical School, Dundee, UK. Conflicts of interest: none declared.
ANAESTHESIA AND INTENSIVE CARE MEDICINE 11:3
Figure 1 Insertion of femoral perineural catheter.
109
Ó 2010 Elsevier Ltd. All rights reserved.
TECHNICAL SKILLS
catheters should be inserted using full aseptic technique, that is hat, mask, gown, gloves and hand scrub.
Outcomes Unfortunately, little evidence exists regarding surgical outcomes after perineural infusion. Compared with opioids, perineural infusions accelerate rehabilitation and reduce hospital length of stay.6 However, continuing a femoral nerve block for 4 days seems to have little impact on health-related quality of life between 7 days and 12 months after knee arthroplasty.8 It is important that future research measures medium- and long-term functional wellbeing. A
REFERENCES 1 Richman JM, Liu SS, Courpas G, et al. Does continuous peripheral nerve block provide superior pain control to opioids? A meta-analysis. Anesth Analg 2006; 102: 248e57. 2 Fowler SJ, Symons J, Sabato S, Myles PS. Epidural analgesia compared with peripheral nerve blockade after major knee surgery: a systematic review and meta-analysis of randomized trials. Br J Anaesth 2008; 100: 154e64. 3 McLeod GA, Dale J, Robinson D, et al. Determination of the EC50 of levobupivacaine for femoral and sciatic perineural infusion after total knee arthroplasty. Br J Anaesth 2009; 102: 528e33. 4 Tran de QH, Munoz L, Russo G, Finlayson RJ. Ultrasonography and stimulating perineural catheters for nerve blocks: a review of the evidence. Can J Anaesth 2008; 55: 447e57. 5 Ilfeld BM, Morey TE, Thannikary LJ, Wright TW, Enneking FK. Clonidine added to a continuous interscalene ropivacaine perineural infusion to improve postoperative analgesia: a randomized, double-blind, controlled study. Anesth Analg 2005; 100: 1172e8. 6 Capdevila X, Dadure C, Bringuier S, et al. Effect of patient-controlled perineural analgesia on rehabilitation and pain after ambulatory orthopedic surgery: a multicenter randomized trial. Anesthesiology 2006; 105: 566e73. 7 Neuburger M, Buttner J, Blumenthal S, Breitbarth J, Borgeat A. Inflammation and infection complications of 2285 perineural catheters: a prospective study. Acta Anaesthesiol Scand 2007; 51: 108e14. 8 Ilfeld BM, Meyer RS, Le LT, et al. Health-related quality of life after tricompartment knee arthroplasty with and without an extendedduration continuous femoral nerve block: a prospective, 1-year followup of a randomized, triple-masked, placebo-controlled study. Anesth Analg 2009; 108: 1320e5.
Figure 2 Elastomeric ball for femoral perineural infusion at 10 ml/hour.
Adjuvunts It seems that infusion of drugs other than local anaesthetics by the perineural route confers no clinical benefit. For example, addition of the a2 agonist clonidine to a ropivacaine interscalene perineural infusion had no effect on pain or rescue medication.5
Mode of delivery Electronic or elastomeric infusion devices may be used to deliver local anaesthetic. Electronic pumps are accurate, but tend to limit mobilization and require hourly nursing observation of drug delivery. On the other hand, elastomeric pumps are light, portable and disposable, and increasingly offer a patient bolus facility (Figure 2). For example, using ropivacaine 0.2%, a patient-controlled technique improved functional recovery and pain relief while decreasing the consumption of rescue analgesics.6
Complications Acute complications associated with perineural catheter techniques include paraesthesia, aspiration of blood and difficulty threading the catheter. A recent observational study of 2285 continuous upper and lower limb nerve blocks showed an 3% incidence of infection related to duration of infusion, but no long-term sequelae.7 These results indicate that all perineural
ANAESTHESIA AND INTENSIVE CARE MEDICINE 11:3
110
Ó 2010 Elsevier Ltd. All rights reserved.
Peripheral nerve catheter techniques
Learning objectives After reading this article, you should be able to: C understand the benefits and side-effects of peripheral nerve catheters C describe the different methods of catheter insertion C be aware of the relationship between anaesthetic concentration, pain relief and motor block.
Graeme McLeod
Abstract Peripheral nerve catheter techniques provide pain relief on movement for upper and lower limb arthroplasty and amputation. The optimal perineural concentration and volume of ropivacaine and levobupivacaine are not known for upper or lower limb block. The most common complication associated with perineural infusion is infection and, thus, aseptic technique is necessary for both insertion of catheters and use of elastomeric balls. Compared with parenteral opioids, perineural infusion of local anaesthetic accelerates rehabilitation and reduces hospital length of stay. However, little evidence exists regarding surgical outcomes, particularly those concerned with functional wellbeing.
the nerve is confirmed by injection of 1 ml increments of local anaesthetic and spread readily seen. Injection of 5 ml aliquots of solution forms a hydrospace around the nerve and creates a space for catheter insertion. Catheter insertion is relatively straightforward in the lower limb, as the catheter is threaded easily, whereas in the upper limb placement is more difficult, and insertion length limited to approximately 5 cm. Catheter position may be confirmed with ultrasound by eliciting movement of the catheter, or spread of further local anaesthetic. Alternatively, stimulating catheters may be used to locate peripheral nerves. This device has a wire placed within its wall, allowing continued nerve stimulation after catheter insertion to optimize placement. Although studies have shown faster surgical block, and a sparing effect on rescue medication, stimulating catheters are not associated with a decrease in side-effects. Realistically, they take more time to place, and have been superseded by direct ultrasound imaging.4
Keywords Arthroplasty; catheter; levobupivacaine; outcome; perineural; pharmacodynamics; ropivacaine
Benefits The principal benefit of perineural infusion of local anaesthetic is extended pain relief into the second and third postoperative days. After lower limb surgery, pain relief is better than patientcontrolled analgesia1 and similar to epidural analgesia after major limb surgery, albeit with reduced opioid-related sideeffects.2 For amputation, continuous pain relief is possible for 1e2 weeks if necessary. Motor block invariably occurs after continuous infusion of commercial preparations of local anaesthetics, but is reduced by using lower concentrations of levobupivacaine3 or ropivacaine, while still maintaining pain relief.
Pharmacodynamics The optimal perineural concentration and volume of ropivacaine and levobupivacaine are not known for upper or lower limb block. As such, there has been a tendency to use the same concentrations of local anaesthetics investigated in epidural block studies. However, a recent trial designed to prevent pain up to 36 hours after knee arthroplasty has shown that the EC50 of femoral levobupivacaine is 0.024%.3 The doseeresponse curves of levobupivacaine and ropivacaine have yet to be determined.
Technical aspects Perineural catheters may be positioned either surgically or percutaneously (see Figure 1). Surgical intervention typically occurs when placing a sciatic catheter during above-knee amputation, with percutaneous tunnelling to the lateral aspect of the thigh. By contrast, anaesthetists identify peripheral nerves using either nerve stimulation or ultrasound, although a combined procedure is often used by inexperienced anaesthetists to verify nerve location. For ultrasound-guided block, a 50 mm or 100 mm Tuohy needle is introduced through the skin and advanced towards the nerve. When inserted out of plane to the ultrasound probe, a needle track can often be seen, whereas when inserted in plane the needle may be visible. Proximity to
Graeme McLeod PGCertMedEd MD MRCGP FRCA FFPMRCA is a Consultant & Honorary Reader in Anaesthesia, University Department of Anaesthesia and Clinical Lead for Anaesthetic Research, Ninewells Hospital & Medical School, Dundee, UK. Conflicts of interest: none declared.
ANAESTHESIA AND INTENSIVE CARE MEDICINE 11:3
Figure 1 Insertion of femoral perineural catheter.
109
Ó 2010 Elsevier Ltd. All rights reserved.
TECHNICAL SKILLS
catheters should be inserted using full aseptic technique, that is hat, mask, gown, gloves and hand scrub.
Outcomes Unfortunately, little evidence exists regarding surgical outcomes after perineural infusion. Compared with opioids, perineural infusions accelerate rehabilitation and reduce hospital length of stay.6 However, continuing a femoral nerve block for 4 days seems to have little impact on health-related quality of life between 7 days and 12 months after knee arthroplasty.8 It is important that future research measures medium- and long-term functional wellbeing. A
REFERENCES 1 Richman JM, Liu SS, Courpas G, et al. Does continuous peripheral nerve block provide superior pain control to opioids? A meta-analysis. Anesth Analg 2006; 102: 248e57. 2 Fowler SJ, Symons J, Sabato S, Myles PS. Epidural analgesia compared with peripheral nerve blockade after major knee surgery: a systematic review and meta-analysis of randomized trials. Br J Anaesth 2008; 100: 154e64. 3 McLeod GA, Dale J, Robinson D, et al. Determination of the EC50 of levobupivacaine for femoral and sciatic perineural infusion after total knee arthroplasty. Br J Anaesth 2009; 102: 528e33. 4 Tran de QH, Munoz L, Russo G, Finlayson RJ. Ultrasonography and stimulating perineural catheters for nerve blocks: a review of the evidence. Can J Anaesth 2008; 55: 447e57. 5 Ilfeld BM, Morey TE, Thannikary LJ, Wright TW, Enneking FK. Clonidine added to a continuous interscalene ropivacaine perineural infusion to improve postoperative analgesia: a randomized, double-blind, controlled study. Anesth Analg 2005; 100: 1172e8. 6 Capdevila X, Dadure C, Bringuier S, et al. Effect of patient-controlled perineural analgesia on rehabilitation and pain after ambulatory orthopedic surgery: a multicenter randomized trial. Anesthesiology 2006; 105: 566e73. 7 Neuburger M, Buttner J, Blumenthal S, Breitbarth J, Borgeat A. Inflammation and infection complications of 2285 perineural catheters: a prospective study. Acta Anaesthesiol Scand 2007; 51: 108e14. 8 Ilfeld BM, Meyer RS, Le LT, et al. Health-related quality of life after tricompartment knee arthroplasty with and without an extendedduration continuous femoral nerve block: a prospective, 1-year followup of a randomized, triple-masked, placebo-controlled study. Anesth Analg 2009; 108: 1320e5.
Figure 2 Elastomeric ball for femoral perineural infusion at 10 ml/hour.
Adjuvunts It seems that infusion of drugs other than local anaesthetics by the perineural route confers no clinical benefit. For example, addition of the a2 agonist clonidine to a ropivacaine interscalene perineural infusion had no effect on pain or rescue medication.5
Mode of delivery Electronic or elastomeric infusion devices may be used to deliver local anaesthetic. Electronic pumps are accurate, but tend to limit mobilization and require hourly nursing observation of drug delivery. On the other hand, elastomeric pumps are light, portable and disposable, and increasingly offer a patient bolus facility (Figure 2). For example, using ropivacaine 0.2%, a patient-controlled technique improved functional recovery and pain relief while decreasing the consumption of rescue analgesics.6
Complications Acute complications associated with perineural catheter techniques include paraesthesia, aspiration of blood and difficulty threading the catheter. A recent observational study of 2285 continuous upper and lower limb nerve blocks showed an 3% incidence of infection related to duration of infusion, but no long-term sequelae.7 These results indicate that all perineural
ANAESTHESIA AND INTENSIVE CARE MEDICINE 11:3
110
Ó 2010 Elsevier Ltd. All rights reserved.