Inclusion criteria:  Written consent. Men and women aged 18 years or more. The physical status from ASA classification I, II or III. BMI <= 34.9 kg / m2. Low risk of respiratory complications. Laparoscopic surgery in the pelvis.  Exclusion criteria:  The physical status from ASA IV or V. BMI> = 35 kg / m2. Neuromuscular disease. Allergy to Anesthetic Agents. Operations on two cavities. Operations on the chest cavity.