How Anesthesiologists Pre-empt Pain

Regional Anesthesia / Local Anesthesia


Optimal pain management is the responsibility of every caregiver who encounters the patient. Opportunities arise prior to a surgical procedure that can make a difference in the outcome regarding pain management. Anesthesiologists are in a unique position with special tools to get a head start on pain management. These tools can have a significant impact on the pain experience, even days later, for better or worse. If you skip a regional anesthetic, your patient might experience more unnecessary pain, days and even months later. Likewise, addressing pain before it happens or comes into one's awareness, can improve the pain experience, resulting in less pain. This is the concept behind pre-emptive analgesia.


With preemptive analgesia, an analgesic regimen is introduced before the onset of noxious stimuli with the goal of preventing sensitization of the nervous system to subsequent stimuli that could amplify pain.


Anesthesiologists have many opportunities to positively influence the recovery of the patient. Consideration of and taking advantage of the various tools available is something that we as anesthesiologists face every day with every patient. It is part of the multimodal care which is the foundation of our practice. A group of tools we use are regional anesthesia techniques to aid in pain management during and / or after a surgical procedure.


In this post, I will describe those regional anesthesia tools, when they are considered, and how they can affect the recovery of the patient. In most institutions, patients undergoing regional anesthesia techniques will be care for by a dedicated acute pain service or anesthesia providers. As such, you should seek expert counsel if you have questions regarding these devices in your patients. Check with your local institution for guidelines. This is a summary directed at the non-pain and non-anesthesia-trained provider. Check out a great resource for more detailed information from NYSORA (New York School of Regional Anesthesia).

https://www.nysora.com/techniques/neuraxial-and-perineuraxial-techniques/


In this post for the non-pain physician, I will review some of the more common regional anesthesia or local anesthesia techniques. This is not meant to be an inclusive review, rather to provide some practical tips about regional anesthesia for both medical providers and the layperson.


N. B. Regional anesthesia techniques are placed by specialists with intense training. As such there may be a consult service (pain service, regional anesthesia service) that manages the day-to-day care of these catheters. Determine your policy in your institution to assure compliance with policy.

Neuraxial anesthesia

Examples: Includes both spinal and epidural analgesia.

Spinal (or intrathecal) anesthesia - injection of medication into the subarachnoid space and into the spinal fluid.

Epidural anesthesia - injection of medication into the epidural space (outside the dura).


Indication: surgeries associated with moderate or intense pain particularly if that pain has a negative effect on ability to take a full breath; pain from rib fracture. Upper or lower abdominal surgery, lower extremity surgery.


Contraindications: patient refusal, coagulopathy, vertebral abnormalities, abnormalities of skin over insertion site


Identification: the epidural catheter can be identified from its midline location on the back, here shown at the lumbar level, or may be more superior at the thoracic vertebral level

Laterality: both sides of the body affected similarly; bilateral effect to analgesia although on occasion can have more pain relief on one side if block is 'patchy'


Medication:

Spinal: local anesthetics

(bupivacaine, mepivacaine,

lidocaine) or opioids (fentanyl, sufentanil, hydromorphone, morphine)

Epidural: local anesthetics (bupivacaine, lidocaine, mepivacaine)

or opioids such as hydromorphone or morphine, alone or in combination.


Duration of analgesia:

Spinal - usually administered as a 'single shot' injection; local anesthetics can last a

range of hours depending on type of the local anesthetic; opioids, such as

hydromorphone, can last up to 24 hours

Epidural - usually a catheter is placed into the epidural space to facilitate continued

administration of medication to provide analgesia for one to four days


Vertebral level:

Spinal - placed at the lumbar level

Epidural - placed at lumbar or thoracic level, depending upon location

and dermatomal level of surgical incision or 'pain generator'


Monitoring: neurologic exam to assure level of motor blockade is receding in patients receiving 'single shot' spinal. Patients who have an epidural in place should always be able to move their legs, even if they are 'numb'; vigilance for local anesthetic toxicity; pulse oximetry, temperature (for fever, source of infection). There is often an order set affiliated with the placement of these catheters to address the monitoring and nursing care necessary in the post-op setting.


Look for: erythema (redness), swelling, purulent discharge from catheter insertion point, assure dressing is intact, catheter remains connected in a closed system


Miscellaneous:

Spinal - patients receiving local anesthetics will experience numbness of the lower extremities and have a motor blockade (weakness) and will need assistance in transferring to bed; fall risk until motor function returns to normal; those receiving spinal opioids are at risk for respiratory depression for 24 hours

Epidural - may have a degree of motor blockade (but usually less than those receiving spinal local anesthetic); with continuous administration of medication through catheter, they are tethered to IV pole equipment

Some protocols may include Foley catheter placement for the duration of the epidural anesthesia


Removal: removed prior to hospital discharge, ideally at least one day prior to discharge


Paravertebral Anesthesia

Indication: pain of the anterior chest wall associated with surgery / medical condition


Contraindication: patient refusal, abnormalities of skin over insertion site, coagulopathy, empyema


Identification: catheter is located just lateral to the midline. In the figure, there are to catheters in place.

Laterality: unilateral or bilateral


Medication: local anesthetics


Duration: can be 'single shot' and therefore dependent on the duration of action of particular local anesthetic. Can also place a catheter to facilitate infusion of local anesthetic for one to four days


Vertebral level: dependent upon the surgical incision, typically placed at various thoracic levels


Monitoring: pulse oximetry, vigilance for local anesthetic toxicity