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Introduction: Intravenous (IV) lidocaine is increasingly part of inpatient multimodal analgesia. Little pediatric literature exists regarding its use beyond the OR; we describe our initial experience.
Methods: Cases from 1/2016 to 7/2018 were retrospectively reviewed. Four groups were defined: Sickle cell/VOE, Post-op, Cancer, and Other. Lidocaine infusion initiation was defined as on Day 0. Plasma concentration (Cp) goal was 2-4 mcg/ml per policy. Data were presented graphically, and linear mixed models were also used to estimate trajectories for average daily pain score and opioid use, in Morphine Milligram Equivalents (MME), with age and post-op days as covariates.
Results: Table 1 shows demographics and mean infusion characteristics. Seven treatments (23%) included an initial bolus. Six infusions (20%) were stopped on Day 0, two for Cp ≥ 10 mcg/ml. One of these patients subsequently had a seizure coincident with a transfusion-related fever (Cp ≤ 5.6 mcg/ml). Paresthesia occurred in 20%. Figure 1 shows the lowest pain scores and MME recorded as percent change from baseline (Day 0 for Post-op, Day -1 otherwise). Figures 2 and 3 show pain score and MME trajectories. Based on modeling, MME decreases, on average, by an estimated 12% (95% CI: 4%-20%) and 13% (95% CI: 3%-21%) per day, in Cancer and Other groups, respectively (p = .006, .011). Pain scores for Cancer patients decrease by an estimated average of 0.7 (95% CI: 0.4-1.0) per day (p < .001).
Discussion: The exact analgesic mechanism of systemic lidocaine is not known, but it may involve anti-inflammatory effects and NMDA receptor modulation. It is not unexpected then that greatest benefit was in the Cancer and Other groups, which included mucositis, typhlitis, colitis, metastasis, and nerve injury. Careful assessment of hepatic blood flow, metabolic factors, and cardiac and neurologic history is a must, with infusion rate adjusted accordingly.
Conclusions: IV lidocaine lowered pain scores and opioid use most in inflammatory and neuropathic pain.
Edmundson, Elizabeth; Anson, Lynn; Miles, Heather; Orpin, Shannan; Staggs, Vincent S.; and Millspaugh, Daniel L., "Lidocaine Infusion for Pediatric Pain: Initial Experience Beyond the OR" (2019). Research at Children's Mercy Month 2019. 12.