A 62-year-old man, 170 cm, 72 kg, with early gastric cancer diagnosed during a medical inspection 1 month earlier was admitted to hospital for a laparoscopic gastrectomy. There was nothing in his medical record except for having taken medication for hypertension that was found in a medical inspection. A preoperative chest X-ray, pulmonary function test and electrocardiogram showed normal findings. Premedication was not administered, and the vital signs measured upon arrival showed a blood pressure (BP), heart rate (HR) and saturation of peripheral oxygen (SpO2) of 140/90 mmHg, 65/min and 99%, respectively. Fentanyl 0.1 mg and thiopental 325 mg were administered with 100% inspired oxygen through the anesthetic mask. After confirming a loss of consciousness, endotracheal intubation was performed after an intravenous injection of succinylcholine 70 mg.
There were no problems with the intubation. After ventilation of both lungs had been confirmed, the tube was fixed to the incisal tooth at a depth of 23 cm, and vecuronium 6 mg was administered for muscle relaxation. A urinary catheter was inserted. Arterial puncturing was performed at the left radial artery for invasive monitoring of the arterial blood pressure. Venous catheterization was performed through the right external jugular vein. Anesthesia was maintained with oxygen 1.5 L/min, air 1.5 L/min, and sevoflurane 1.5-3.0 vol%, while the muscle relaxant was administered intermittently. Mechanical ventilation was performed with a tidal volume (TV) respiratory rate (RR) and peak airway pressure (P
max) of 500 ml, 12/min, and 16 cmH
2O, respectively. After inducing anesthesia, the partial end-tidal carbon dioxide pressure (P
ETCO2), BP, HR and SpO
2 was 37 mmHg, 130/90 mmHg, 80/min and 99%, respectively. For laparoscopy, a total of 5 trocars (3 of 5 mm, 11 mm, and 12 mm) were inserted and an 11 mm Hasson trocar was connected to a carbon dioxide gas pump (CO
2 endoflator, Olympus, Japan). To secure the operative view and space, 12 mmHg of CO
2 was provided and the patient was turned to the reverse trendelenburg position, and the operation proceeded. Auscultation on both lungs after repositioning showed regular breathing sounds. The P
max after the pneumoperitonium was 22 cmH
2O, and the P
ETCO2 was 38 mmHg. Approximately 70 minutes after the pneumoperitonium, the Pmax increased suddenly to 30 cmH
2O, and then endotracheal suction was performed to exclude the effect of endotracheal excretion but the amount excreted was small. Subsequently, the P
max was maintained at the higher 30 cmH
2O, and the SpO
2 decreased to 96%. His vital signs then showed a P
ETCO2, BP, and HR of 39 mmHg, 110/60 mmHg and 75/min, respectively, while the arterial blood gas analysis (ABGA) indicated a pH, partial pressure of arterial carbon dioxide (PaCO
2) and PaO
2 of 7.37, 48 mmHg and 118 mmHg, respectively. Upon auscultation, the breathing sound of the right side was normal but the breathing sound of the left lung decreased significantly. Manual ventilation was performed to preclude the tube from moving into the bronchus and the endotracheal tube was withdrawn back to 4 cm with auscultation. However, the breathing sound of the left lung still decreased. There were no significant changes in the patient's BP and HR, but the friction of inspired oxygen (FiO
2) was increased and another ABGA was used under consideration of the incidence of pneumothorax. The results indicated a pH, PaCO
2 and PaO
2 of 7.33, 53 mmHg and of 105 mmHg, respectively. The pneumoperitonium was terminated immediately and a chest X-ray (chest AP view) was performed. The findings on the chest x-ray confirmed the incidence of pneumothorax in the left lung (
Fig. 1), and 12-French catheter (Trocar catheter, Mallinckrodt medical Inc, Ireland) was inserted along the midaxillary line into the space between the 5
th and 6
th rib after consulting with the surgeon. After catheterization, the Pmax was decreased to 24 cmH
2O and the breathing sound of the left lung showed a favorable change. The P
ETCO2 was 38 mmHg, and the SpO
2 increased to 99%. The ABGA findings indicated a pH of 7.37, a PaCO
2 of 44 mmHg, and a PaO
2 of 158 mmHg, indicating significant improvement. After confirming the stability in the patient and performing a pneumoperitonium with the same gas pressuring pressure for the operation, the FiO
2 was reduced to 0.6 and mechanical ventilation was performed with a TV of 500 ml and RR of 14/min. The measured ABGA showed a pH, PaCO
2 and PaO
2 of 7.39, 44 mmHg, 192 mmHg, respectively, whereas the P
max and P
ETCO2 was 24 cmH
2O and 32 mmHg, respectively. The total surgical time was 4 hours.
After his spontaneous respiration returned, muscle relaxation was achieved using a mixture of glycopyrrolate 0.4 mg and neostigmine 2 mg, and the endotracheal tube was removed after he reached consciousness. The patient did not complain of any discomfort or respiratory disturbance except for surgical site pain, and he was transported to the post-anesthesia recovery unit. Oxygen at 5 L/min was administered through a venturi mask when the pulse oximetry indicated a SpO
2 of 99%. After the patient's consciousness returned to normal, he was transferred to the ward while oxygen of 3 L/min was provided through a venturi mask. A chest X-ray performed on the chest PA view confirmed a considerable decrease in the pneumothorax (
Fig. 2). During his hospitalization, the patient did not complain of any discomfort of dyspnea. On postoperative day 4, the catheter was removed, and on postoperative day 6, a chest X-ray and computerized tomography (CT) did not show any abnormal findings. The patient was discharged home in good condition.