Vagal electrostimulation in postoperative thoracic surgery reduces the systemic inflammatory response and cardiopulmonary complications: an experimental study in pigs

BACKGROUND: Conventional thoracotomy (CT) often leads to systemic inflammatory response syndrome (SIRS), which induces several clinical complications. CT remains widely used in low-income institutions. Although minimally invasive surgical procedures, such as robotic surgery (RS), have been used to prevent many of the complications inherit from the surgical procedure. Here, we investigated the protective effect of vagus nerve stimulation (VNS) in a pre-clinical model during CT or RS and postoperative period (POP) relative to clinical complications and inflammatory control. The objective was to compare hemodynamic features and cytokine levels in the blood, lung, and bronchoalveolar lavage (BAL) fluids of animals subjected to CT or RS with or without VNS. METHODS: Twenty-four minipigs were subjected to 12 animals CT and 12 animals RS, with or without VNS, and accompanied 24 h later by pulmonary lobectomy. Blood samples for evaluating the hemodynamic parameters were collected before the surgical preparation, immediately after the beginning of VNS, and every 4 h until 24 h after the lobectomy. BAL fluid and lung tissue were collected at the end of the experiment. Cytokine levels were evaluated in the blood, BAL fluid, and lung tissues. RESULTS: VNS maintained a more stable heart rate during POP and decreased the incidence of overall cardiac complications while preventing increase in IL-6 levels 12 h after lobectomy, compared to sham animals. No differences were found in cytokine expression in the BAL fluid and lung tissue in any of the studied groups. CONCLUSIONS: Taken together, our data suggested that VNS should be considered a non-pharmacological tool in the prevention of the exacerbated inflammatory response responsible for severe clinical complications, especially in more aggressive surgical procedures.