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Correspondence  |   July 1999
Regression of Sensory Analgesia with Lumbar Epidural Catheters 
Author Notes
  • Chef de Clinique; Department of Anesthesiology; Medical Center Alkmaar; Alkmaar, The Netherlands;
Article Information
Correspondence
Correspondence   |   July 1999
Regression of Sensory Analgesia with Lumbar Epidural Catheters 
Anesthesiology 7 1999, Vol.91, 317. doi:
Anesthesiology 7 1999, Vol.91, 317. doi:
To the Editor:-I read with interest the study by Boylan et al. [1 ] comparing epidural bupivacaine-morphine analgesia with patient-controlled analgesia after abdominal aortic surgery. However, I have a major concern.
After a loading dose of 10 ml of 2% lidocaine followed by 15 ml of 0.25% bupivacaine via a lumbar epidural catheter, sensory block in the epidural group was probably at an adequate thoracic level of upper abdominal surgery. Forty-eight-hour postoperative analgesia was provided by epidural infusion of morphine combined with 0.125% bupivacaine at a mean infusion rate of 4.3 ml/h and a few 5-ml bolus injections of 0.25% bupivacaine in some patients. This dose of bupivacaine is too low to prevent regression of sensory analgesia below the level of surgery. This would have been noticed if not only visual analog pain scores but also levels of sensory analgesia had been obtained, as in any other study investigating the analgesic effects of neuraxial local anesthetics.
Nonlipophilic opioids such as morphine slow the regression of sensory analgesia, as was demonstrated by Hjortso et al. [2 ] Using a lumbar epidural catheter, they maintained a thoracic level of sensory analgesia for 16 h by adding 0.5 mg/h of morphine to 8 ml/h of 0.5% bupivacaine (nearly eight times more bupivacaine than that used by Boylan et al. [1 ]).
Ferrante et al. [3 ] also used a lumbar epidural catheter to infuse 4 ml/h of 0.25% bupivacaine combined with the nonlipophilic meperidine after they had established sensory anesthesia to T6. The dose of bupivacaine in their study (which was approximately twice as high as the dose used by Boylan et al. [1 ]) was chosen to allow regression of sensory block. They found that the mean time for regression of five dermatomes was 6 h.
In conclusion, Boylan et al. [1 ] infused bupivacaine via a lumbar epidural catheter after upper abdominal surgery without reporting levels of sensory analgesia and using lower doses than those that caused early regression of sensory block in another study. Therefore, in my opinion, bupivacaine did not contribute to postoperative analgesia, and their study, in fact, compared intravenous morphine to epidural morphine.
Robert Jan Quist, M.D.
Chef de Clinique; Department of Anesthesiology; Medical Center Alkmaar; Alkmaar, The Netherlands;
(Accepted for publication February 1, 1999.)
REFERENCES 
REFERENCES 
Boylan JF, Katz J, Kavanagh BP, Klinck JR, Cheng D, DeMajo WC, Walker PM, Johnston KW, Sandler AN: Epidural bupivacaine-morphine analgesia versus patient-controlled analgesia following abdominal aortic surgery. Anesthesiology 1998; 89:585-93
Hjortso N-C, Lund C, Mogensen T, Bigler D, Kehlet H: Epidural morphine improves pain relief and maintains sensory analgesia during continuous epidural bupivacaine after abdominal surgery. Anesth Analg 1986; 65:1033-6
Ferrante MF, Fanciullo GJ, Grichnik KP, Vaisman J, Sacks GM, Concepcion MA: Regression of sensory anesthesia during continuous epidural infusions of bupivacaine and opioid for total knee replacement. Anesth Analg 1993; 77:1179-84