During shoulder arthroscopic surgery, extravasation of irrigation fluid can occur around the shoulder and trachea, compressing the upper airway. Although the extravasation is generally reabsorbed asymptomatically within 12 hours, there are cases that lead to reintubation or life-threatening complications. Furthermore, the soft tissue edema around the shoulder may extend to the thoracic cage, compress the chest and induce the respiratory distress immediately after surgery. The investigators attempt to determine the effect of shoulder arthroscopic surgery on respiratory mechanics. Changes in respiratory mechanics and arterial blood gases were measured and compared before and after the shoulder arthroscopic surgery.

Currently, most shoulder surgeries are performed with arthroscopy. The advantages of shoulder arthroscopic surgery are decreased blood loss due to minimal incision for scope, a reduced operation time, minimization of surgical stress, and rapid recovery time after surgery. During shoulder arthroscopic surgery, extravasation of irrigation fluid can occur around the shoulder and trachea, compressing the upper airway. Although the extravasation is generally reabsorbed asymptomatically within 12 hours, there are cases that lead to reintubation or life-threatening complications. Furthermore, the soft tissue edema around the shoulder may extend to the thoracic cage, compress the chest and induce the respiratory distress immediately after surgery. From these facts, the mechanism of respiratory discomfort after shoulder arthroscopic surgery may be because the upper airway obstruction or restrictive pathology due to direct compression of thoracic cage by the soft tissue edema. There have been no studies on the respiratory effect of shoulder arthroscopic surgery. We have observed frequent and severe respiratory discomfort after the shoulder arthroscopic surgery. Therefore, in this study we attempt to determine the effect of shoulder arthroscopic surgery on respiratory mechanics. Changes in respiratory mechanics and arterial blood gases were measured and compared before and after the shoulder arthroscopic surgery.

Inclusion Criteria:

• Patients undergoing arthroscopic shoulder rotator cuff repair surgery
• American society of anesthesiologist (ASA) class I or II
• Patients under 70 yrs.

Exclusion Criteria:

• Patients older than 70 yrs,
• Patients with anatomical derangement of upper airway,
• Patients with pulmonary or cardiac disease,
• Patients with a history of laryngeal or tracheal surgery or hemodynamic instability

patients undergoing arthroscopic shoulder rotator cuff repair surgery