Intrathecal sufentanil produces sensory changes without hypotension in male volunteers

[Intrathecal but not systemic sufentanil reduces the consumption of propofol for bispectral index-guided sedation]

OBJECTIVE

The addition of opioids to local anesthetics in spinal anesthesia modulates some aspects of anesthesia and analgesia. We evaluate the effect of adding different doses of intrathecal and subcutaneous sufentanil on propofol requirements for sedation during spinal anesthesia.

MATERIAL AND METHODS

Prospective clinical trial randomizing patients undergoing knee arthroscopy to 4 groups. Group 1 received 12.5 mg of 0.75% hyperbaric bupivacaine (HBB); Group 2, 12.5 mg of HBB plus 2.5 microg of intrathecal sufentanil; Group 3, 12.5 mg of HBB plus 5 microg of intrathecal sufentanil; and Group 4, 12.5 mg of HBB plus 5 microg of subcutaneous sufentanil. When spinal anesthesia had been induced, a bispectral index (BIS) monitor was connected and baseline values were recorded for each patient. Sedation was then initiated with propofol at a dose of 2.5 microg/ml, using an effect-site target-controlled infusion system to maintain a BIS value between 60 and 75. BIS, vital signs, total propofol dose (TPD), mean infusion dose (MID), and awakening time were recorded.

RESULTS

One hundred patients were included in the study. MID and TPD were lower in Groups 2 and 3 than in Groups 1 and 4 (P = .009). Consumption of propofol was 35.23% less in Group 2 and 37.50% less in Group 3 than in Group 1 (P = .001).

CONCLUSIONS

The addition of 2.5 microg or 5 microg of intrathecal sufentanil to HBB reduces MID, TPD, and consumption of propofol in patients undergoing spinal anesthesia; the addition of 5 microg of subcutaneous sufentanil does not produce this effect.

Automated regular boluses for epidural analgesia: a comparison with continuous infusion

BACKGROUND

Intermittent epidural bolus dosing is a method of drug delivery that can prolong the duration of labour analgesia induced by a combined spinal epidural (CSE). In this randomized, double-blinded study, we compared the analgesic efficacy of two drug delivery systems: regular intermittent epidural boluses and continuous epidural infusion and assessed the incidence of breakthrough pain after CSE.

METHODS

With the approval of the Hospital Ethics Committee, we recruited 60 parturients into this randomized controlled trial. A CSE was performed with intrathecal fentanyl 25 mug in all patients. The parturients were then randomly allocated into two groups. The infusion group received a continuous epidural infusion of levobupivacaine 0.1% with fentanyl 2 microg/mL at a rate of 10 mL/h. The bolus group received 5-mL epidural boluses every half hour. The sample size was computed to detect a 40% reduction in the rate of breakthrough pain.

RESULTS

The bolus group had a lower incidence of breakthrough pain than the infusion group (10% vs. 37%, P < 0.05). The bolus group also had significantly higher satisfaction scores for labour analgesia: 97+/-8 (mean+/-SD) vs. 89+/-7 (P < 0.05).

CONCLUSION

Automated regular bolus delivery of epidural analgesia when compared with continuous infusion decreased the incidence of breakthrough pain and increased maternal satisfaction. In a busy obstetric unit, this may also serve to decrease the anesthetists' workload.

Assessment of peripheral neuropathy using measurement of the current perception threshold with the neurometer in patients with type 2 diabetes mellitus

Measurement of current perception threshold (CPT) using the Neurometer at 2000, 250 and 5 Hz assesses function in three different nerve fibre types. This method was used to investigate peripheral neuropathy in 116 patients with type 2 diabetes mellitus and 38 healthy controls. The CPT at 2000 Hz was significantly higher in diabetic patients than in controls, and showed a significant negative correlation with motor and sensory nerve conduction velocities. At 250 Hz, CPT showed a significant positive correlation with the vibration perception threshold. At 5 Hz, the change in systolic blood pressure in the Schellong test in patients with hypoaesthesia tended to be less than in those with normal sensation or hyperaesthesia. Significantly higher CPT values were obtained in patients with proliferative diabetic retinopathy and macroalbuminuria. These data suggest that CPT is useful in detecting abnormalities of myelinated as opposed to unmyelinated nerve fibres in patients with type 2 diabetes.

Selective spinal anesthesia for outpatient laparoscopy. III: sufentanil vs lidocaine-sufentanil

PURPOSE

The efficacy of low dose intrathecal lidocaine-sufentanil was compared with intrathecal sufentanil for short duration outpatient gynecological laparoscopy.

METHODS

Thirteen ASA I and II patients undergoing gynecological laparoscopy were studied in a randomized double-blind trial. Patients received either intrathecal 10 mg lidocaine plus 10 microg sufentanil (Group LS) or intrathecal 20 microg sufentanil (Group S), each diluted to 3 mL with sterile water through a 27g Whitacre needle in the sitting position. Sensory and motor recovery were assessed with pinprick and a modified Bromage scale.

RESULTS

One of seven Group LS patients and two of five Group S patients required conversion to general anesthesia for failed skin test with forceps. Two of the remaining three Group S patients felt sharpness with skin incision. The study was terminated early because of inadequate anesthesia in Group S. The small sample size (n = 9) made statistical analysis uninformative.

CONCLUSION

Intrathecal 20 microg sufentanil is unsuitable as a sole agent for gynecological laparoscopy.