What does a spinal and sedation procedure involve?

What Does a Spinal and Sedation Procedure Involve?

A spinal and sedation procedure involves the administration of local anesthetic into the subarachnoid space (spinal anesthesia) combined with intravenous sedative medications to provide patient comfort while maintaining cardiorespiratory function during medical procedures.

Spinal Anesthesia Component

• Spinal anesthesia (also called subarachnoid block) involves injecting local anesthetic into the cerebrospinal fluid in the subarachnoid space to block nerve impulses from the lower body 1
• The procedure typically uses local anesthetics such as lidocaine or bupivacaine, with doses carefully calculated based on patient factors and the desired level of anesthesia 1
• For most procedures, lower doses of intrathecal bupivacaine (< 10 mg) are recommended to reduce associated hypotension 2
• Sometimes intrathecal opioids (preferably fentanyl rather than morphine or diamorphine) may be added to prolong postoperative analgesia 2
• A test dose (2-3 mL of 1.5% lidocaine) is often administered before the full dose to check for unintentional subarachnoid space penetration 1

Sedation Component

• Procedural sedation refers to administering sedatives with or without analgesics to induce a state that allows patients to tolerate unpleasant procedures while maintaining cardiorespiratory function 2
• The level of sedation typically targeted is moderate sedation (previously called "conscious sedation"), where patients respond purposefully to verbal or tactile stimulation 2
• Common sedative medications used include:
  • Midazolam (a benzodiazepine) 2, 3
  • Propofol (often titrated at 25-75 mcg/kg/min) 2, 4
  • Sometimes ketamine, which may help counteract hypotension 2, 5

Pre-procedure Assessment

• A thorough pre-procedure evaluation is essential to identify medical history and physical findings that could adversely affect sedation outcomes 2
• Assessment should include:
  • Airway evaluation
  • Cardiopulmonary status
  • Current medications
  • Allergies
  • Previous anesthesia experiences 2
• The American Society of Anesthesiologists (ASA) physical status classification helps determine risk, with ASA IV and V patients often requiring an anesthesia specialist 2

Monitoring During the Procedure

• Continuous monitoring of vital signs is essential during both spinal anesthesia and sedation 2
• Standard monitoring includes:
  • Pulse oximetry
  • Blood pressure measurement
  • Heart rate monitoring 2
• Drug delivery and monitoring should be performed by certified nursing personnel, nurse anesthetists, or anesthesiologists 2
• Capnography (monitoring of end-tidal CO2) may be used to detect early respiratory depression, especially with deeper levels of sedation 2

Procedural Details

1. Patient positioning (often lateral or sitting position for spinal insertion) 2
2. Sterile preparation of the injection site 2
3. Administration of local anesthetic to the skin and deeper tissues 1
4. Insertion of a spinal needle into the subarachnoid space 1
5. Confirmation of correct placement by observing cerebrospinal fluid flow 1
6. Injection of the calculated dose of local anesthetic 1
7. Positioning the patient appropriately after injection (often supine with slight head elevation) 2
8. Administration of sedative medications intravenously, titrated to the desired level of sedation 4, 3

Post-procedure Care

• All patients should have a period of bed rest and observation after the procedure 2
• Vital signs and lower limb neurological function should be assessed at regular intervals 2
• Supervised ambulation should occur after an appropriate duration of observation 2
• Most patients can be discharged later the same day or observed overnight depending on the procedure 2

Benefits of Combined Spinal and Sedation

• The sedation component provides:
  • Reduced anxiety and improved patient comfort 6
  • Amnesia for the procedure 2
  • Improved patient satisfaction 4, 3
• The spinal component provides:
  • Profound anesthesia for procedures below the umbilicus 2
  • Reduced need for systemic analgesics 2
  • Potentially fewer respiratory complications compared to general anesthesia 2

Common Pitfalls and Considerations

• Sedation depth exists on a continuum, and patients can inadvertently progress to deeper levels of sedation than intended 2
• Providers should be prepared to rescue patients from one level deeper than the targeted sedation level 2
• Hypotension is a common side effect of spinal anesthesia and may be exacerbated by sedative medications 2, 7
• Respiratory depression can occur with sedation, particularly when combined with intrathecal opioids 2
• For patients with obstructive sleep apnea, special considerations are needed as they are more susceptible to the respiratory depressant effects of sedatives and opioids 2
• Having the patient awake enough to provide feedback during the procedure is desirable as it allows for early detection of complications 2