Page 27 - CASA Bulletin of Anesthesiologisy 2022 9(6)-1 (3)

Vol. 9, No 6, 2022

ketamine, which is a psychotropic mediation with profound analgesic properties shows great
promise in the treatment for chronic patients with concomitant depression 28, 29 .

U k , k ’ A -depressive
properties is mediated through activation of mTOR in the prefrontal cortex. The anti-depressive
effects of ketamine can also be seen within a few hours to days following treatment unlike other
antidepressants which takes months before beginning to see its effect 29, 30 K ’
effect onset is particularly useful in patients with suicidal ideations who are at high risk of
carrying out suicidal behaviors at any given time .
31
Lidocaine

Lidocaine infusions have opioid sparing properties and has shown to decrease opioid
consumption and improve quality of life following complex spine surgeries making it an ideal
adjunct for pain control in opioid dependent patients 32, 33 . The mechanism of pain relief and anti-
hyperalgesia is mediated by NMDA and voltage gated sodium channel inhibition . Systemic
34
lidocaine also has anti-inflammatory properties. Systemic lidocaine stimulates the release of
superoxide anions and interleukin 1B that inhibits neutrophil priming, a process where
k ‘ ’ . Other
35
mechanisms of lidocaine include inhibition of voltage gated calcium channels, potassium
channels, glycine receptors and G protein pathways.

Dexmedetomidine

Dexmedetomidine is another opioid sparing adjunct that has recently garnered much
attention for its diverse effects including analgesia, anxiolysis, perioperative sympatholysis and
preservation of respiratory functions. Dexmedetomidine is a 2 agonist with moderate analgesic
properties that work on peripheral and central 2 receptors. Its high lipophilicity allows it to pass
the blood brain barrier, get absorbed into the cerebrospinal fluid and bind to the 2 receptors of
the spinal cord to decrease nociceptive neurotransmitters such as Substance P . In a study by
33
Hwang et al., dexmedetomidine infusion was compared with remifentanil infusion in patients
undergoing posterior lumbar interbody fusion surgery. Patients who received a dexmedetomidine
infusion had significantly lower pain scores at the immediate and late postoperative periods (48
hr) and had lower hydromorphone requirements for 48 hours compared to the remifentanil group
.
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Dexamethasone

Major surgeries such as complex spine surgeries cause massive release of proinflammatory
cytokines and profound systemic inflammation. Glucocorticoids such as dexamethasone can
suppress the production of pro-inflammatory cytokines and prostaglandin synthesis by inhibiting
Phospholipase A2 and the expression of COX-2 enzymes subsequently reducing postoperative
hyperalgesia secondary to central sensitization. Preoperative administration of intravenous
dexamethasone has shown to reduce acute pain during mobilization up to 24 hours after primary
disc surgery and glucocorticoids have also shown to have sustained postoperative opioid sparing
effects up to 3 days postoperatively 37, 38, 39
.
Mg

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