How do you administer spinal anesthesia for this case?

Spinal Anesthesia Administration Protocol

For spinal anesthesia administration, use pencil-point spinal needles with lower doses of intrathecal bupivacaine (<10 mg) combined with fentanyl as the intrathecal opioid to minimize hypotension and respiratory depression. 1, 2

Patient Preparation and Positioning

• Position the patient in either lateral decubitus or sitting position, depending on the surgical site and patient comfort 1, 3
• Ensure proper monitoring is in place including pulse oximetry, ECG, and non-invasive blood pressure monitoring before beginning the procedure 1, 2
• Administer supplemental oxygen during the procedure to prevent hypoxemia 1, 2
• Consider administering nonparticulate antacids, H2-receptor antagonists, and/or metoclopramide for aspiration prophylaxis before the procedure 1

Medication Selection and Dosing

• Use lower doses of intrathecal bupivacaine (<10 mg) to reduce associated hypotension in elderly or compromised patients 1, 2
• Add fentanyl (10-25 mcg) rather than morphine or diamorphine as the intrathecal opioid to reduce respiratory and cognitive depression 1, 2
• Consider the smallest effective dose of local anesthetic to achieve the desired effect while minimizing side effects 4, 5
• For hip fracture repair or lower limb surgery, hyperbaric bupivacaine is preferred for more predictable spread 2, 3

Administration Technique

• Use pencil-point spinal needles instead of cutting-bevel spinal needles to minimize the risk of post-dural puncture headache 1
• Perform the procedure under strict aseptic technique 4
• Inject the anesthetic solution slowly to avoid rapid spread and high block 4
• After injection, position the patient according to the desired spread of anesthesia (e.g., lateral position with fractured hip inferior for hip fracture repair) 1
• Monitor for immediate complications including hypotension, bradycardia, and high spinal block 4, 6

Sedation Management

• Use minimal sedation during spinal anesthesia in elderly or compromised patients 1, 2
• If sedation is required, use small doses of midazolam or propofol with careful titration 1
• Avoid opioids for sedation due to the risk of respiratory depression 1, 2

Adjunctive Techniques

• Consider peripheral nerve blockade (femoral nerve or fascia iliaca block) as an adjunct to extend the period of postoperative non-opioid analgesia 1, 2
• For hip fracture repair, anterior approaches (femoral nerve/fascia iliaca block) are more amenable to ultrasound guidance and reduce the risk of deep hematoma in anticoagulated patients 1

Monitoring and Management of Complications

• Monitor vital signs continuously during and after the procedure 1, 4
• Treat hypotension promptly with intravenous fluids and vasopressors if needed 2, 6
• Have resuscitative equipment, oxygen, and emergency drugs immediately available 4
• Be prepared to manage potential complications including failed block, high spinal, total spinal, and local anesthetic systemic toxicity 4, 6

Special Considerations

• For patients with respiratory compromise, spinal anesthesia is preferred over general anesthesia to avoid airway manipulation and mechanical ventilation 2
• For anticoagulated patients, ensure INR is <1.5 before neuraxial anesthesia 2
• For elderly patients, use reduced doses of local anesthetics to minimize hemodynamic effects 1, 2
• For outpatient procedures, consider lower doses of long-acting agents to produce an adequately short spinal block 1, 7

Common Pitfalls and Caveats

• Avoid simultaneous administration of spinal and general anesthesia as this is associated with precipitous falls in blood pressure 1, 3
• Be aware that medication errors in preparing spinal anesthesia mixtures are common - carefully measure all components 8
• Remember that the total dose of local anesthetic is the most important determinant of both therapeutic and unwanted effects 7
• Recognize that cardiovascular effects associated with sympathetic block are the most common side effects but can be successfully treated with volume expansion and vasopressors 7, 6