Effect of local anesthetics on platelet physiology and function.

Local anesthetics are often used at the site of injury or mixed with platelet-rich plasma to reduce pain when treating orthopedic and sports-related injuries. Local anesthetics have been shown to have deleterious effects on stromal cells, but their impact on platelets has not been investigated. In this study, we aimed to assess the effects of lidocaine, bupivacaine, and ropivacaine on platelet health. Based on the deleterious effects of local anesthetics on nucleated cells, we hypothesized that these compounds would affect platelet viability, intracellular physiology, and function. Platelet preparations were derived from randomly selected donors and exposed to lidocaine 1%, bupivacaine 0.75%, ropivacaine 0.5%, and saline at 1:1 and 1:3 ratios. Platelet morphology, viability, intracellular calcium, production of radical oxygen species (ROS), apoptosis, and adhesion were assessed via fluorescent microscopy and flow cytometry. Bupivacaine resulted in increased ROS production, calcium dysregulation, apoptosis, and reduced platelet adhesion. By contrast, ropivacaine and lidocaine were similar to saline in most assays, except for a low degree of mitochondrial stress as evidenced by increased ROS production. Ultimately, bupivacaine 0.75% was harmful to platelets as evidenced by reduced platelet viability, adhesion, and increased apoptosis, whereas lidocaine 1% and ropivacaine 0.5% were relatively safe at the 1:1 and 1:3 dilutions. Clinical significance: Lidocaine 1% and ropivacaine 0.5% can be used at up to a 1:1 ratio with platelet preparations to reduce the pain and discomfort of PRP procedures while maintaining platelet therapeutic potential.