Enhanced recovery after surgery (ERAS) protocols or fast track surgery are a number of
interventions which are carried out in the perioperative period. They are aimed to
decrease the harmful effects of surgery on the body and help the patient recover better
after surgery. ERAS has been shown to reduce the length of hospital stay, overall
hospital costs, opioid consumption in the perioperative period and to reduce complication
rates.
One of the most important components of ERAS is adequate perioperative pain control using
a multi-modal analgesic approach to help decrease dependence on opioids and provide
better recovery and less postoperative hospital stay. Also, the severity and duration of
acute postoperative pain is one of the predictors of chronic postsurgical pain (CPSP).
Neuroplasticity (spinal sensitization) following the trauma of surgery can transform an
acute pain to chronic pain if not treated effectively by aggressive management of acute
pain.
Lidocaine (or 2-(diethylamino)-N-(2.6-dimethylphenyl) acetamide) is the main prototype of
amino-amide local anesthetics. It has analgesic, anti-hyperalgesic and anti-inflammatory
properties, which enable its use as a general anesthetic adjuvant. It can reduce
nociception, cardiovascular responses to surgical stress, postoperative pain, and
analgesic requirements.
Accordingly, Lidocaine infusion can have a role in enhancing postoperative quality of
recovery, decreasing incidence of chronic postoperative pain and even increasing overall
survival in patients undergoing major surgeries like in pancreatectomy.
The Systemic effects of intravenous Lidocaine infusion depends on its plasma level which
is affected by the rate and dose of administration, drug interactions and speed of
metabolism and elimination. Around 90% of lidocaine undergoes hepatic metabolism
(CYP3A4), with the production of active metabolites. During lidocaine continuous
infusion, the accumulation of these metabolites may inhibit its biotransformation and
might be involved in some cases of intoxication. The clearance rate of lidocaine is
approximately 0.85 L/kg/h. Finally, lidocaine is eliminated by the kidney (10% of
lidocaine is eliminated unchanged in the urine).
The target plasma concentrations for Lidocaine for providing effective analgesia is 2.4 ±
0.6 μg/mL, while side effects as - have been reported when the plasma concentration was
higher than 5-8 μg/mL. The suggested dosing regimens mentioned in literature to achieve
this effective plasma level while avoiding toxicity is a bolus of 1-2 mg/kg at surgery
start followed by infusion of 1-2 mg/kg/h over the duration of the surgery which is a
relatively wide range, specially, considering the wide variability in type and duration
of surgeries, demographics, physical and medical status of patients and type of
anesthetic agents and drugs used which all can affect Lidocaine activity, elimination &
toxicity.
To the best of our knowledge, no evidence exist in the literature that can point towards
the ideal dosing regimen for intravenous Lidocaine infusion that can achieve the desired
valuable clinical effects while decreasing the incidence of adverse side effects among
the wide variety of surgeries and patients encountered within ERAS protocols.