The doses recommended below should be regarded as a guide for use in the average adult. Spinal anaesthesia for surgery: 2-4 ml (10-20 mg Bupivacaine hydrochloride). The spread of anaesthesia obtained with Bupivacaine depends on several factors including the volume of the solutions and the position if the patients during and following the injection. When injected in the L3-L4 intervertebral space with the patient in the sitting position, 3 ml of Bupivacaine spreads to the T7- T10 spinal segments. With the patient receiving the injection in the horizontal position and then turned supine, the blockade spine spreads to T4-T7 spinal segments. It should be understood that the level of spinal anaesthetic can be unpredictable in a given patient.