Theresa Lii, M.D., is currently a pain medicine fellow at Stanford and is part of the Stanford Fellowship in Anesthesia Research (FARM) program. Her research interests include evaluating the effectiveness of opioid-sparing pharmacologic treatments as well as exploring the impact of rapid-acting psychiatric interventions for patients with acute and chronic pain.
BACKGROUND: Effective analgesia is essential in managing traumatic rib fractures. Intravenous lidocaine (IVL) is effective in treating perioperative pain, acute pain in the emergency department, cancer pain in hospice, and outpatient chronic neuropathic pain. Our study examined the associations between IVL versus epidural analgesia (EA) and pain for the treatment of acute rib fracture in the inpatient setting.METHODS: We performed a retrospective study involving adults admitted to an academic level I trauma center from June 1, 2011 to June 1, 2016 with consults to the pain service for acute rib fracture pain. Eighty-nine patients were included in the final analysis (54 IVL and 35 EA patients). Both groups had usual access to opioid medications. The primary outcome was absolute change in numeric pain scores during 0-24 and 24-48hours after initiating IVL or EA, compared with baseline. Secondary outcomes include opioid consumption, incentive spirometry, supplemental oxygens, pneumonia, endotracheal intubation and length of hospital stay.RESULTS: Numeric pain scores differed at baseline (mean 5.6 for IVL vs 4.5 for EA, p=0.01), while age, injury severity, and number of fractured ribs were similar. IVL and EA were associated with similar reductions in numeric pain scores within 0-24 and 24-48hours (mean -2.9 for IVL vs -2.3 for EA during both periods, p=0.19and p=0.17 respectively) . There was greater non-neuraxial opioid consumption with IVL compared with EA (98.6 vs 22.3 mg morphine equivalents (MME) at 0-24hours, p=0.0005; 105.6 vs 18.9 MME at 24-48hours, p<0.0001). When epidural opioids were analyzed, the EA group was exposed to higher total MME at 0-24hours (655.2 vs 98.6 MME, p<0.0001) and 24-48hours (586 vs 105.6 MME, p=0.0001), suggesting an opioid sparing effect of IVL.CONCLUSION: Our results suggest that IVL is similar to EA in numeric pain score reduction, and that IVL may have an opioid sparing effect when taking neuraxial opioids into account. IVL may be an effective alternative to epidurals for the treatment of rib fracture pain. It should be considered for patients who have contraindications to epidurals or are unable to receive an epidural in a timely manner.
View details for DOI 10.1136/rapm-2019-101120
View details for PubMedID 32503863
Pain modulates rhythmic neuronal activity recorded by Electroencephalography (EEG) in humans. Our laboratory previously showed that rat models of acute and neuropathic pain manifest increased power in primary somatosensory cortex (S1) recorded by electrocorticography (ECoG). In this study, we hypothesized that pain increases EEG power and corticocortical coherence in different rat models of pain, whereas treatments with clinically effective analgesics reverse these changes. Our results show increased cortical power over S1 and prefrontal cortex (PFC) in awake, freely behaving rat models of acute, inflammatory and neuropathic pain. Coherence between PFC and S1 is increased at a late, but not early, time point during the development of neuropathic pain. Electroencephalography power is not affected by ibuprofen in the acute pain model. However, pregabalin and mexiletine reverse the changes in power and S1-PFC coherence in the inflammatory and neuropathic pain models. These data suggest that quantitative EEG might be a valuable predictor of pain and analgesia in rodents.
View details for DOI 10.1097/j.pain.0000000000000652
View details for PubMedID 27347647
Oscillations are fundamental to communication between neuronal ensembles. We previously reported that pain in awake rats enhances synchrony in primary somatosensory cortex (S1) and attenuates coherence between S1 and ventral posterolateral (VPL) thalamus. Here, we asked whether similar changes occur in anesthetized rats and whether pain modulates phase-amplitude coupling between VPL and S1. We also hypothesized that the suppression of burst firing in VPL using Z944, a novel T-type calcium channel blocker, restores S1 synchrony and thalamocortical connectivity. Local field potentials were recorded from S1 and VPL in anesthetized rats 7 days after sciatic chronic constriction injury (CCI). In rats with CCI, low-frequency (4-12 Hz) synchrony in S1 was enhanced, whereas VPL-S1 coherence and theta-gamma phase-amplitude coupling were attenuated. Moreover, Granger causality showed decreased informational flow from VPL to S1. Systemic or intrathalamic delivery of Z944 to rats with CCI normalized these changes. Systemic Z944 also reversed thermal hyperalgesia and conditioned place preference. These data suggest that pain-induced cortical synchrony and thalamocortical disconnectivity are directly related to burst firing in VPL.
View details for DOI 10.1097/j.pain.0000000000000362
View details for PubMedID 26683108
Thalamocortical oscillations are critical for sensory perception. Although pain is known to disrupt synchrony in thalamocortical oscillations, evidence in the literature is controversial. Thalamocortical coherence has been reported to be increased in patients with neurogenic pain but decreased in a rat model of central pain. Moreover, theta (4 to 8 Hz) oscillations in primary somatosensory (S1) cortex are speculated to predict pain in humans. To date, the link between pain and network oscillations in animal models has been understudied. Thus, we tested the hypothesis that pain disrupts thalamocortical coherence and S1 theta power in two rat models of pain. We recorded electrocorticography (ECoG) waveforms over S1 and local field potentials (LFP) within ventral posterolateral thalamus in freely behaving rats under spontaneous (stimulus-independent) pain conditions. Rats received intradermal capsaicin injection (Cap) in the hindpaw, followed hours later by chronic constriction injury (CCI) of the sciatic nerve lasting several days. Our results show that pain decreases coherence between LFP and ECoG waveforms in the 2- to 30-Hz range, and increases ECoG power in the theta range. These changes are short-lasting after Cap and longer-lasting after CCI. These data might be particularly relevant to preclinical correlates of spontaneous pain-like behavior, with potential implications to clinical biomarkers of ongoing pain.
View details for DOI 10.1016/j.pain.2014.01.013
View details for PubMedID 24457192
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