Spinal anesthesia-involves injection of small volumes of local anesthetic solution into the subarachnoid space at the level of the lumbar spine.
Spinal anesthesia-a spinal needle is passed between two adjacent spinal processes via the supraspinous ligament, interspinous ligament, ligament flavum, dura mater, and arachnoid mater, and the CSF is aspirated and then local anesthetic is injected.
Spinal anesthesia-the spinal needle can be used as a single shot method or a catheter can be used for repeated or continuous dosing.
Spinal anesthesia-older patients have a greater spread of the agent to extra dermatomes.
Spinal anesthesia-the spread of the anesthesia depends on the solution density compared to that of the CSF, the total dose and total volume of the anesthetic administered.
The length of anesthesia is variable, as little as 30 minutes with lidocaine and as long as 6 hours with tetracaine.
Spinal anesthesia-may cause hypotension by causing sympatholytic induced vasodilation and bradycardia.
Spinal anesthesia-hypotension may be worse in patients with hypovolemia or have cardiac disease.