Systemic Lidocaine Infusion for Acute Pain Management in a Surgical Intensive Care Unit: A Single-Arm Pilot Trial

Objectives: Currently, there are a lack of data on the use of systemic lidocaine infusion in critically ill surgical patients, particularly regarding optimal dosing and monitoring. This study aimed to assess the feasibility of conducting a subsequent full-scale, randomized controlled trial (RCT) on the use of systemic lidocaine infusion in surgical intensive care units (ICUs). Methods: A single-center, prospective, single-arm pilot trial was conducted at the surgical intensive care unit (ICU) at Houston Methodist Hospital. The study population included 12 subjects over 18 years old who were admitted to the surgical ICU after open abdominal surgery. A low-dose lidocaine infusion of 10-30 mcg/kg/min within 1 h of ICU admission. Results: The feasibility outcomes encompassed recruitment, retention, and withdrawal rates. The study initially screened 18 participants, all of whom were successfully enrolled, resulting in a recruitment rate of 100%. However, 6 participants (33.3%) from the enrolled group were subsequently withdrawn for various reasons, resulting in a retention rate of 12 participants (66.7%). All 12 remaining participants were included in the analysis at the baseline stage. The safety outcomes included adverse events and serum lidocaine levels, with no serious adverse events reported. Dizziness and hypertension were the most frequently reported adverse events in their respective categories, affecting 16.7% of patients each. Four patients (33%) exhibited elevated lidocaine levels exceeding 5 mcg/mL; however, no clinical features of lidocaine toxicity were observed. This study adhered to the CONSORT 2010 extension for pilot and feasibility trials. In accordance with these guidelines, no formal hypothesis testing for efficacy was performed. The exploratory outcomes included a reduction in opioid requirements, as measured by morphine milligram equivalents (MMEs), and pain scores. The median MMEs decreased from 22.6 on postoperative day 0 to 2.5 on day 3. The pain scores decreased by 1.09 units per day (β = -1.09; 95% CI: -1.82 to -0.36; p = 0.003); however, the absence of a control group limits the robustness of this observation. Conclusions: A large-scale, randomized controlled trial to evaluate the safety and efficacy of systemic lidocaine infusion in the surgical intensive care unit (ICU) seems feasible, with minor adjustments to the eligibility criteria and improved collaboration among nurses, anesthesiologists, and surgeons.