On Effects of Ketamine to Axillary Block in Hand Surgery

To the EditorWe have been using axillary block for upper extremity surgery anesthesia in the Istanbul Hand Surgery Microsurgery Center since 1992. Although articain is fast in effect, acting as a local anesthetic, it seems to be insufficient for controlling tourniquet pain.[1] We decided to combine ketamine and articain, to be able to begin operative procedures immediately and to control tourniquet pain.

In search of a new anesthetic agent, a prospective study was designed to compare the effectiveness of the two drugs, articaine and ketamine, used in three different combinations. Three groups of patients, each consisting of 15 patients (25 to 45 years old), were formed randomly. Only ketamine (2 mg/kg + 38 ml 0.9 percent NaCl) was used in one group, with Ultracaine (articaine 2 percent - 40 ml) in the second group and, with Ultracaine + ketamine (articaine 2 percent - 40 ml + ketamine 2 mg/kg) in the third group. The time interval between the application of the tourniquet (300 mmHg) and the first sign of pain was recorded in all groups. The operation was started immediately in Groups 1 and 3 that were given ketamine. In Group 2, the operation was delayed for 10 min for the onset of anesthesia.

We observed that ketamine alone was not sufficient to achieve adequate anesthesia duration (mean 0.1 hr). Ultracaine only patients had a mean 1.2 hr of anesthesia (onset of tourniquet pain), while patients who had Ultracaine and ketamine together had a mean anesthesia time of 4.2 hr.

The sudden onset of anesthesia in Groups 1 and 3 who were given ketamine may be explained as a result of antogonism to NMDA receptors.[2] [3] Intrathecal ketamine was shown to block axonal conduction by Gebhardt.[4] We believe that an axonal conduction block may contribute to the analgesic mechanism of regional ketamine. We concluded that articaine and ketamine in combination are more successful than articaine alone. We explain this by the following reasons. Ketamine might increase the binding capacity of local anesthetic to albumin alpha acid glucoprotein and change ionic balance. Another mechanism might be due to two isomers (S) and (R): S isomer blocks the opiate receptors and R isomer has hypnotic effects.[5]

@prefauf:Adnan Noyan, M.D.

REFERENCES

• 1 Noyan A. Our experience of continuous periaxillary block utilizing Ultracaine in hand surgery. In: Prithvi R, Erdine S, eds. Management of Pain: A World Perspective Bologna, Italy: Monduzzi Editore 1995: 315-317
• 2 Durrani Z. Ketamine for intravenous regional anesthesia. In: Domino EF, ed. Status of Ketamine in Anesthesiology Ann Arbor, MI: NPP Books; 1990
• 3 Takahashi H, Miyazaki M, Nanbu T. The NMDA-receptor antagonist ketamine abolishes neuropathic pain after epidural administration in a clinical case.  Pain . 1998;  75 391-394
• 4 Gebhardt B. Pharmacology and clinical results with peridural and intrathecal administration of ketamine.  Anesthetist . 1994;  43Sup 2 S34-40
• 5 White P F. Ketamine update: its clinical uses in anesthesia. In: Domino EF, ed. Status of Ketamine in Anesthesiology Ann Arbor, MI: NPP Books; 1990