Does cough increase the spread of subarachnoid anesthesia?

Two matched groups of eight patients were given hyperbaric tetracaine (12 mg) intrathecally. One group was instructed to cough vigorously three times after injection. The mean upper level of analgesia by pinscratch technique was the sixth thoracic dermatome in both groups. We conclude that three vigorous coughs do not influence the spread of spinal anesthesia.