Diagnostic epidural opioid technique.

Diagnostic epidural blocks were performed on 27 chronic pain patients sequentially using saline, fentanyl, and lidocaine solution. The patients were divided into one of four groups based on their response to the epidural solutions: placebo response group--pain relief with placebo solutions; fentanyl response group--pain relief with epidural fentanyl; lidocaine response group (LRG)--pain relief with lidocaine but not fentanyl; and no response group--no pain relief with any of the solutions used. The four groups were compared on the basis of age, sex, site of pain, duration of pain, narcotic use, pain assessment index, and workmen's compensation claims. The comparisons resulted in the conclusion that LRG patients had a much longer average duration of pain than the other groups. On the basis of the information gathered, it was theorized that, despite their response to epidural lidocaine, LRG patients may actually be a group of operant pain patients. Their failure to receive analgesia from epidural fentanyl may be a learned response such that they associate any sensory input from the affected area as painful. If follow-up studies support these findings, then the diagnostic opioid technique may be a more sensitive tool in diagnosing chronic pain.

Patient-controlled analgesia in pediatric surgery.

Patient-controlled analgesia (PCA) with a microprocessor-operated infusion syringe was first suggested for human use in 1965. Clinical studies from the United States and Europe have shown this form of analgesia to be well accepted by adults, but the use of this technology for children has not been studied. We evaluated PCA in 15 consecutive pediatric surgical patients between the ages of 11 and 18 years undergoing major thoracic or abdominal surgery. The patients and their parents were instructed in the use of the equipment prior to surgery and PCA was initiated after the patients left the recovery room. The mean duration of PCA was 2.6 days. No serious mechanical difficulties with the infusion apparatus were encountered. The acceptance of PCA was excellent with only two patients preferring some other method of analgesia. pain relief was assessed twice daily by a registered nurse using a verbal-visual pain scale. On a 1 to 10 scale average pain relief was 7.2. Eight of the patients had had a previous operation, and seven of these reported that PCA was a better method of achieving pain control. A comparison of the 15 study patients with 15 previous patients with similar procedures indicated that PCA patients used less analgesia in the postoperative period, although they tended to use more in the first 24 hours. PCA is found to be a safe and effective means of analgesia in pediatric patients. Adequate pain relief was achieved with less analgesia and with less nursing attention. This technology is recommended for postoperative pediatric patients.

Epidural morphine for postoperative pain relief: a dose-response curve.

Different doses of epidural morphine were studied in order to determine their effectiveness in providing postoperative pain relief after surgery of the lower extremities and their relationship to the incidence of untoward reactions. The study was carried out in a double-blind fashion using five dosages of epidural morphine (0.5, 1.0, 2.0, 4.0, and 8.0 mg) and included 60 patients. The higher doses of morphine (2.0, 4.0, and 8.0 mg) were equally effective and more effective than the lower doses (0.5 and 1.0 mg) in providing postoperative analgesia. Nausea and vomiting were encountered more frequently with the highest dose (8.0 mg) and this finding was statistically significant (P less than 0.03). No statistically significant difference was found between the doses studied with regard to itching, urinary retention, and respiratory depression; the latter was evaluated in a subgroup of 20 patients. These data suggest that effective postoperative pain relief after surgery of the lower extremities can be achieved with relatively low doses of morphine sulfate and with minimal side effects. For the type of surgery studied, 2 mg morphine sulfate appeared to be the optimum dose.

pain relief mediated by implantable drug delivery devices.

Various totally implantable drug delivery systems from single access ports to micropumps are now available for administration of repeated boluses, and continuous or programmable infusions. In this respect, emphasis is given to a relatively cheap, totally implantable system for self-administering intraspinal opiates in the treatment of cancer pain. The SECOR pump system, developed by Cordis, consists of a dual pump with refill port and safety valve. The volume of the pliable reservoir is 12 ml and refill is accomplished with a 25-G needle. The bolus delivered with each transcutaneous activation of the pumps is 0.1 ml. Clinical results demonstrated that this patient-controlled drug delivery system is safe and provides excellent pain relief associated with terminal cancer. A possible advantage of this drug delivery system over continuous infusion pumps is that patients can elect to have the morphine delivered only when they feel pain. Thus pain relief would be maximized and tolerance build-up would be minimized.