Optimization of Tracheal Intubation and Ventilatory Management in a Rat Thoracotomy Model.

OBJECTIVE

To establish a practical and reproducible method for procedural standardization during tracheal intubation and ventilatory management during thoracotomy in rats, and evaluate the invasiveness of thoracotomy as a control condition.

METHODS

Tracheal length and diameter were measured in adult female Wistar rats to determine appropriate intubation devices. Positive end-expiratory pressure (PEEP) was titrated (0-5 cm H2O) under open chest conditions using a macroscopic lung expansion score. In a separate experiment, the rats underwent left thoracotomy with incision lengths of 1, 2, or 3 cm, followed by macroscopic and histological assessments 4 weeks later.

RESULTS

Mean tracheal length and inner diameter were 59.7 and 1.63 mm, respectively. A 16-gauge, 48-mm intravenous catheter was suitable for intubation. Optimal lung expansion was achieved at a PEEP of 4 cm H2O. Macroscopic pleural adhesions and post-operative weight loss were not observed in any thoracotomy groups. Histological examination revealed mild pleural thickening and fibrin deposition without differences in incision length.

CONCLUSIONS

A standardized intubation and ventilatory protocol with PEEP set at 4 cm H2O provides stable lung expansion during thoracotomy in rats. A thoracotomy up to 3 cm in length induces minimal pathological changes and is suitable as a control condition in experimental thoracic surgery models.