{
  "abstract": "Background Regional anesthesia is widely used in pain management to reduce opioid requirements, enable early mobilization and improve postoperative outcomes. However, commonly used combinations of local anesthetics and adjuvants can crystallize under clinical conditions, which generates concerns regarding neurotoxicity and embolization complications.Purpose This study aimed to determine whether microporous filters can effectively eliminate crystals formed by mixing local anesthetics and adjuvant.Method Commonly used local anesthetics (lidocaine, mepivacaine and ropivacaine) and adjuvants (dexamethasone, dexmedetomidine and sodium bicarbonate) were combined and tested. The mixture was passed through 5 µm and 0.2 µm filters, and the presence of crystals before and after filtration at specific time points and volumes was assessed microscopically.Results Lidocaine mixtures showed no detectable crystallization under any condition. In contrast, crystallization occurred in most combinations containing mepivacaine or ropivacaine, with the highest grades observed in ropivacaine–bicarbonate mixtures (grade 5). Filtration reduced crystallization grades by 1–3 points depending on the mixtures, but did not eliminate crystals in most mixtures. Crystals also persisted after longer intervals and with larger filtration volumes. No meaningful difference was observed between the 5 µm and 0.2 µm filters.Conclusion Crystallization can occur in anesthetic–adjuvant mixtures that are commonly used for regional anesthesia. Although filtration reduces these crystals, it does not eliminate crystals, especially those with large volumes or unstable combinations.",
  "authors": [
    {
      "affiliations": [
        "Department of Anesthesiology and Pain Medicine, Chung-Ang University Hospital, Dongjak-gu, Republic of Korea"
      ],
      "name": "Chan Su Park"
    },
    {
      "affiliations": [
        "Department of Anesthesiology and Pain Medicine, College of Medicine, Chung-Ang University, Dongjak-gu, Republic of Korea",
        "Department of Anesthesiology and Pain Medicine, Chung-Ang University Gwangmyeong Hospital, Gwangmyeong-si, Republic of Korea"
      ],
      "name": "Min Kyoung Kim"
    },
    {
      "affiliations": [
        "Department of Anesthesiology and Pain Medicine, Chung-Ang University Hospital, Dongjak-gu, Republic of Korea",
        "Department of Anesthesiology and Pain Medicine, Chung-Ang University, Dongjak-gu, Republic of Korea"
      ],
      "name": "Geun Joo Choi"
    },
    {
      "affiliations": [
        "Department of Anesthesiology and Pain Medicine, Chung-Ang University Hospital, Dongjak-gu, Republic of Korea",
        "Department of Anesthesiology and Pain Medicine, Chung-Ang University, Dongjak-gu, Republic of Korea"
      ],
      "name": "Chong Wha Baek"
    },
    {
      "affiliations": [
        "Department of Laboratory Medicine, Chung-Ang University College of Medicine, Dongjak-gu, Republic of Korea",
        "Department of Laboratory Medicine, Chung-Ang University Gwangmyeong Hospital, Gwangmyeong-si, Republic of Korea"
      ],
      "name": "Oh Joo Kweon"
    }
  ],
  "title": "Crystallization of local anesthetic mixtures with adjuvants and the effect of micropore filtration",
  "uid": "e8227e65-4895-5cef-a96d-bb1bddccaf77"
}