Respiratory and haemodynamic effects of lateral thoracotomy or sternotomy in mechanically ventilated rats

We compared left lateral thoracotomy and sternotomy in rats which were mechanically ventilated for at least 1 h in order to perfect the technique and the surveillance of thoracic opening. Lateral thoracotomy proved to be superior to sternotomy as it was associated with a lower mortality within the first 24 h (20% compared with 50%; p less than 0.05). Lateral thoracotomy causes a smaller reduction in mean blood pressure (104 +/- 11 vs. 71 +/- 7 mm Hg; mean +/- SD; p less than 0.05). Furthermore, following lateral thoracotomy, the rats had a higher postoperative PaO2 (77 +/- 16 vs. 72 +/- 7 Torr) and a lower PaCO2 (29.5 +/- 1.5 vs. 35 +/- 4.3 Torr), although these differences were not statistically significant.