Results: At the end of surgery, PaO2 in the LRM group (258.95 ± 47.94 mmHg) was higher than that in the control group (228.93 ± 45.67 mmHg), p < 0.05; the PaO2/FiO2 value in the LRM group (517.90 ± 95.87 mmHg) was higher than that in the control group (457.86 ± 91.33 mmHg), p < 0.05.