Mechanical Ventilation of Obese Patients During Oral Surgical Procedures

The prevalence of obese patients in a great number of patients scheduled for elective surgery under general anesthesia has been on the increase. Recent studies suggest an intraoperative protective mechanical ventilation for the obese. Surgical procedures in the oral cavity increase the risk of perioperative complications of obese patients. By making this randomized clinical study, investigators want to determine whether the protective intraoperative ventilation with the use of higher positive end-expiratory pressure and recruitment maneuvers compared to ventilation with low positive end-expiratory pressure and without recruitments cause better postoperative respiratory function parameters of obese patients during oral surgical procedures. Investigators also aim to establish the fact which value of a positive end-expiratory pressure has a favorable impact on the respiratory function without negative hemodynamic effect.

Oral surgeries of obese patients in general endotracheal anesthesia are a special challenge as in the most extensive types of interventions any form of regional anesthesia is inadequate, duration of surgery is short but requires deep level of anesthesia after which a quick awakening and most rapid release from hospital are expected, with a known high perioperative risk complications of obese patients.

Oral surgical procedures in the oral cavity due to possible postoperative upper airway oedema increase the risk of postoperative hypoxia in obese patients. Therefore, it is important to intraoperatively mechanically ventilate obese patients with the aim of good ventilation-perfusion ratio without creating new atelectasis, to minimize the risk of postoperative respiratory decompensation and to provide rapid recovery.

As the prevalence of obesity in the world increases as chronic diseases, the number of obese patients scheduled for oral surgery is growing. Studies involving different ways of intraoperative mechanical ventilation of obese patients are mostly processed laparoscopic abdominal studies that can not exclude the additional effect of intraabdominal pressure on the formation of pulmonary atelectasis.

Eligibility Criteria:
Inclusion Criteria:

* body mass index greater than 30 kg / m2
* surgical operation in the area of the oral cavity in general endotracheal anesthesia - cystectomy, alveotomy, mandible and maxilla osteosynthesis after jaw trauma, operation of retained and affected teeth, orthodontic surgical treatment of jaw deformity, benign tumor surgery
* ASA (American Society of Anesthesiologists) Classification of Patients 2-3
* duration of general endotracheal anesthesia from 1 to 2.5 hours

Exclusion Criteria:

* Allergy to anesthetics
* previous lung operations
* documented heart disease (NYHA II, III)
* Pulmonary disease (asthma, COPD)
* Obstructive pulmonary function disorders according to spirometry: FVC(forced vital capacity) may and may not be normal, FEV1(forced expiratory volume at one second) \<80%, FEV1 / FVC \<80%)
* neuromuscular disease
* clinical sign of cardiovascular disease established during preoperative treatment
* pregnancy
* Patients who, for some reason after surgery, have to remain intubated and mechanically ventilated in the Intensive Medicine Unit
* refuse to sign informed consent