Dosage of Lipid Emulsions as an Antidote to Lipid-Soluble Substances

Introduction: Lipid emulsions are increasingly used as an antidote to lipophilic drug intoxications. The dose recommended by the American Society of Regional Anesthesia is used primarily for the treatment of local anesthetic systemic toxicity. There is insufficient information about what the dose of lipid emulsions (LE) should be in other intoxications depending on their severity. Aim: To determine the LE dose in a shock or haemodynamic instability in patients with acute exogenous intoxications treated with LE. Materials and methods: Forty-nine patients with acute lipophilic drug intoxications were treated with LE in the Clinic of Toxicology at the Naval Hospital in Varna. Statistical analysis was performed using the statistical functions of Excel 2016 and the Statistica 7.0 software package. Results: The percentage of patients receiving a low dose of LE of 0.3 ml/kg (93.87%) was significantly higher than the percentage of patients treated with a medium (2.04%) and a high dose (4.08%) of LF. The high dose of LE of 1.5 ml/kg recommended by the American Society of Regional Anesthesia was administered to two patients (4.08%). In severe intoxications with exotoxic shock, the rate of LE administration varies from 20 ml/h to 40 ml/h. Conclusions: In severe intoxications with cardiotoxic syndrome and haemodynamic instability, LE should be used in the dose as suggested by the American Society of Regional Anesthesia. It is possible to use lower doses of LE in the range of 0.3–0.6 ml/kg in all moderate poisonings administered by continuous intravenous infusion for 12-24-48 hours. No side effects were observed at these doses.

Updates on Wound Infiltration Use for Postoperative Pain Management: A Narrative Review

Local anesthetic wound infiltration (WI) provides anesthesia for minor surgical procedures and improves postoperative analgesia as part of multimodal analgesia after general or regional anesthesia. Although pre-incisional block is preferable, in practice WI is usually done at the end of surgery. WI performed as a continuous modality reduces analgesics, prolongs the duration of analgesia, and enhances the patient’s mobilization in some cases. WI benefits are documented in open abdominal surgeries (Caesarean section, colorectal surgery, abdominal hysterectomy, herniorrhaphy), laparoscopic cholecystectomy, oncological breast surgeries, laminectomy, hallux valgus surgery, and radical prostatectomy. Surgical site infiltration requires knowledge of anatomy and the pain origin for a procedure, systematic extensive infiltration of local anesthetic in various tissue planes under direct visualization before wound closure or subcutaneously along the incision. Because the incidence of local anesthetic systemic toxicity is 11% after subcutaneous WI, appropriate local anesthetic dosing is crucial. The risk of wound infection is related to the infection incidence after each particular surgery. For WI to fully meet patient and physician expectations, mastery of the technique, patient education, appropriate local anesthetic dosing and management of the surgical wound with “aseptic, non-touch” technique are needed.

Multiple myeloma and malignant lesions: a potential risk factor for local anesthetic systemic toxicity

BackgroundMultiple myeloma is a cancer of plasma cells that often leads to complications including osteolytic bone lesions, nephropathy and neuropathy. Multiple myeloma is only one etiology of many cancer pain conditions that may necessitate interventional pain treatment when refractory to multimodal medications. Notably, local anesthetic systemic toxicity is a rare but life-threatening complication of local anesthetic administered for these interventions.Case presentationA 50–60-year-old woman presented with multiple myeloma complicated by chronic bone pain and in an acute pain crisis. A fluoroscopic-guided L4–5 epidural catheter was placed with clinical doses of bupivacaine for comfort to undergo MRI of the spine. Soon after, she became tachycardic, tachypneic and hypoxic requiring non-invasive positive pressure airway support. As this respiratory distress was attributed to a large pleural effusion, a pigtail catheter was inserted in the intensive care unit with submaximally dosed lidocaine infiltration. She then developed a left bundle branch block followed by cardiovascular collapse minimally responsive to high-dose inotrope and vasopressor support. Lipid emulsion was started with dramatic therapeutic response and recovery to baseline. A CT of the thoracolumbar spine showed worsening extensive lytic lesions throughout all vertebral bodies and ribs from diffuse myeloma.ConclusionsPatients with oncologic lesions focal to the thoracolumbar spine may be at higher risk for local anesthetic systemic toxicity from palliative epidurals due to increased cancer-related angiogenesis. Likewise, local anesthetic infiltration for procedures near any malignant sites could have a similar risk and may require lower initial fractionated dosages with increased vigilance.