One hour before thoracic surgery, the patient-subjects received diazepam 0.15 mg kg-1 as premedication. After arriving at the operating theatre, standard monitoring system practices were applied, including heart rate (HR), systolic arterial pressure (SAP), diastolic arterial pressure (DAP), mean arterial pressure (MAP), and pulse oximetry (SpO2). Moreover, an intra-vein cannula was placed, and the infusion of multi-electrolytic fluid 5-10 ml kg-1 h-1 was started. After pre-oxygenation, atropine 0.5 mg and fentanyl 3 µg kg-1 were given, and the induction of anaesthesia with thiopentone 5-7 mg kg-1 was started. Suxamethonium was administered for neuromuscular blockade, and bronchial intubation with a Robertshow double lumen tube was performed. The left bronchus was intubated for right lung surgery, and the right bronchus was intubated for left lung surgery. Tube placement was checked via auscultation and fiberscope. Anaesthesia was maintained with sevoflurane, additional fentanyl doses were used if needed, and neuromuscular blockade was obtained with vecuronium 0.1 mg kg-1. Additionally, 0.1 mg kg-1 dose of morphine was given subcutaneously for postoperative pain control. Patients were also ventilated with O2 (oxygen) and AIR (air) mixture, using the following settings: volume control intermittent positive pressure ventilation, FiO2 (oxygen fraction) 0.4, Vt (tidal volume) 6-10 ml/kg, and f (frequency) 12-15 /min. Furthermore, end tidal CO2 (carbon dioxide) was monitored due to normocapnia maintenance (4.0-5.3 kPa). At the end of surgery, intercostal blockade was brought about with 0.5% bupivacaine, with 5 ml for each nerve. Finally, the neuromuscular blockade was reversed with neostigmine 0.04 mg kg-1 and with atropine 0.01 mg kg-1.