Spread of analgesia and ventilatory response to carbon dioxide following epidural somatostatin.

The effects of somatostatin, injected into the epidural space, on analgesia and control of ventilation were studied in 25 patients aged 41 +/- 9 yrs (mean +/- SD). The patients were allocated to three groups to receive: Group I--1 mg of somatostatin in 2 ml saline (n = 13); Group II--1 mg of somatostatin in 10 ml saline (n = 6); and Group III--somatostatin in a loading dose of 250 micrograms followed by an infusion of 125 micrograms h-1 (n = 6). Segmental cutaneous analgesia, assessed by pinprick, without loss of thermal sensibility or motor blockade was found in all patients. Onset times and durations of analgesia were 15 +/- 2 min and 69 +/- 19 min (mean +/- SD) in Group I and 14 +/- 2 min and 68 +/- 11 min in Group II. The extent of dermatome analgesia at 30 min and 60 min after somatostatin injection, respectively, was: T6 +/- 2 to T12 +/- 1, T4 +/- 2 to L1 +/- 2 in Group I, and T7 +/- 3 to L1 +/- 3, T3 +/- 1 to T12 +/- 2 in Group II. Continuous analgesia with onset of 16 +/- 2 min and extending from T7 +/- 1 to T12 +/- 1 was observed in Group III. No side-effects were observed. The control of ventilation studies in eight patients in Group I by the Read's rebreathing method did not show any significant change.