Anesth Analg 2007;104:1303-1304
© 2007 International Anesthesia Research Society
doi: 10.1213/01.ane.0000260554.17916.ef
LETTER TO THE EDITOR
Section Editor:
Lawrence Saidman
Outpatient Continuous Peripheral Nerve Catheters
Elie Joseph Chidiac, MD, and
Samuel Perov, MD
Department of Anesthesiology, Michigan Orthopaedic Specialty Hospital, Wayne State University/Detroit Medical Center, Detroit, Michigan, echidiac{at}med.wayne.edu
To the Editor:
Recently, Swenson et al. (1) reported on the results from a retrospective study of 620 patients sent home with continuous popliteal, interscalene or femoral catheters for postoperative analgesia. As the authors point out, there is no peer-reviewed publication that thoroughly discusses "how to create a program for continuous peripheral nerve blocks at home," with all the practical aspects and supporting literature. Our Institution began a similar program in 2003. Like Swenson et al., we had to develop our own protocols, including preoperative and postoperative patient instructions, a process for the patient to contact an anesthesiologist, and a process for outpatient telephone follow-up with data sheets. To date, we have discharged over 1000 patients with continuous peripheral nerve blocks to their homes (CPNBH). Our results are similar to those of the Utah group, with a low incidence of catheter site infection, catheter dislodgement, fluid leakage, shortness of breath (with interscalene CPNBH), difficulty with catheter removal at home, and prolonged neurological deficits.
Two fundamental differences between our protocol and that of Swenson et al. (1) are the concentration of the local anesthetic infusate and their decision to use ultrasound for placement without nerve stimulation.
The authors chose 0.25% bupivacaine at 5 mL/h and suggest that there is no consensus on a specific local anesthetic or a specific concentration. However, most of their references on CPNBH (and nearly all the recent literature on the subject) have used 0.2% ropivacaine or 0.125% bupivacaine, with good results. One of their references used 0.25% bupivacaine at 5 mL/h for popliteal catheters but found a very high incidence of leg tingling (2). We have three concerns here: First, 0.25% bupivacaine as a continuous infusate causes tissue damage and muscle apoptosis in minipigs (3). Second, catheter migration, although extremely rare, may cause increased blood concentrations and systemic toxicity (4). Finally, the higher concentration may result in motor blockade, with episodes of falling. Swenson et al. (1) make no mention of the degree of motor blockade that was obtained in their patients. Excessive numbness and motor weakness may result in injury from improper positioning of the surgical extremity or loss of proprioception, and vulnerable nerves (the ulnar nerve at the elbow, the radial nerve at the midhumeral level, and the common peroneal nerve at the fibular head) could be injured (5).
With respect to the routine use of ultrasound guidance, we believe this is the first large-scale study of peripheral nerve catheter placement with ultrasonography and without nerve stimulation. However, all the studies on continuous techniques that were referenced by the authors used nerve stimulation as the method of choice for catheter placement. Their references on ultrasound guidance were for single-shot blocks. Ultrasonography may be added to nerve stimulation, but should not replace it (5). While we do not know the degree of sensory and motor blockade obtained in this study, we know, from the authors’ own references, that catheter placement with nerve stimulation allows the infusion of a more dilute solution. A further refinement is the use of simulating catheters, where more precise placement results in blocks of faster onset and better quality (6,7). A continuous infusion of 0.0625% levobupivacaine through a stimulating catheter has the same effect as 0.125% levobupivacaine through a nonstimulating catheter (7), suggesting a closer perineural location of the stimulating catheter.
In summary, we applaud Swenson et al. in their effort to publicize this method of postoperative pain control and encourage the reader to use the authors’ web site for guidance and advice on creating CPNBH programs.
REFERENCES
- Swenson JD, Bay N, Loose E, et al. Outpatient management of continuous peripheral nerve catheters placed using ultrasound guidance: an experience in 620 patients. Anesth Analg 2006;103:1436–43.[Abstract/Free Full Text]
- White PF, Issioui T, Skrivanek GD, et al. The use of a continuous popliteal sciatic nerve block after surgery involving the foot and ankle: does it improve the quality of recovery? Anesth Analg 2003;97: 1303–9.[Abstract/Free Full Text]
- Zink W, Sef C, Bohl JRE, et al. The acute myotoxic effects of bupivacaine and ropivacaine after continuous peripheral nerve blockades. Anesth Analg 2003;97:1173–9.[Abstract/Free Full Text]
- Capdevila X, Pirat P, Brinquier S, et al. Anesthesiology 2005;103:1033–45.[Web of Science][Medline]
- Boezaart AP. Perineural infusion of local anesthetics. Anesthesiology 2006;104: 872–80.[Web of Science][Medline]
- Casati A, Fanelli G, Koscielniak-Nielsen Z, et al. Using stimulating catheters for continuous sciatic nerve block shortens onset time of surgical block and minimizes postoperative consumption of pain medication after halux valgux repair as compared with conventional nonstimulating catheters. Anesth Analg 2005;101: 1192–7.[Abstract/Free Full Text]
- Rodriguez J, Taboada M, Carceller J, et al. Stimulating popliteal catheters for postoperative analgesia after hallux valgus repair. Anesth Analg 2006;102:258–62.[Abstract/Free Full Text]
|
