Video-assisted thoracoscopic surgery is the procedure of choice for the diagnosis of diseases of pleura, undiagnosed small peripheral pulmonary nodules and interstitial lung disease.[1]Adequate surgical exposure during thoracoscopy requires partial or complete collapse of the operative lung. Traditionally, thoracoscopic surgeries have been done using a double-lumen endotracheal tube (DLT). However, placement of DLT has risks,[2] and its use in small children is limited by size (smallest DLT is 26Fr and smallest Univent is of 3.5 mm ID).The use of two-lung ventilation during thoracoscopies has been studied in the past. Satisfactory use of a single-lumen tube (SLT) in thoracoscopic pleural biopsy,[3] wedge resection of lung[3] and thoracoscopic sympathectomy[4] have been shown. Two-lung ventilation with a SLT using low tidal volumes and increased respiratory rate showed normal acid base gases values in all patients undergoing thoracoscopic surgery for primary spontaneous pneumothorax.[5]General anaesthesia with two-lung ventilation is generally necessary for infants and small children, as they often will not tolerate collapse of one lung.[6] Placement of an endotracheal tube in a child with a potentially irritable airway also increases the risk of perioperative respiratory complications.[7]
CASE REPORT
We report the management of two 7-year-old, American society of Anaesthesiologists grade II, children posted for thoracoscopic lung biopsy for confirmation of their diagnosis of sarcoidosis and interstitial lung disease. Both had clinical and radiological evidence of upper and lower respiratory tract infections and pre-operative investigations revealed hypoxia.After obtaining a written informed consent from the parents, the children were pre-medicated with syrup Promethazine. Standard monitoring was instituted. Anaesthesia was induced with Fentanyl, Propofol and Vecuronium and a size 2.5 Proseal laryngeal mask airway (PLMA) was inserted in both the patients. Anaesthesia was maintained with Sevoflurane 2–3% in (50:50) O2–N2O (oxygen-nitrous oxide). The patients were placed in the left lateral decubitus position. Before introduction of the thoracoscope, both lungs were deflated by disconnection of the breathing circuit. Subsequent pneumothorax created by insertion of ports further led to lung collapse, precluding the use of carbon dioxide (CO2) insufflation. Biopsy specimens were retrieved using an endovascular stapler while both lungs were ventilated using a tidal volume of 6 mL/kg and a rate of 25 cycles/min with airway pressures ranging between 22 and 27 cm of H2O. Post-operative pain relief was achieved by local infiltration and non-steroid anti-inflammatory drugs. Emergence from anaesthesia and post-operative period was uneventful for both the patients.Because both our patients were small children, debilitated, with poor pulmonary reserve, scheduled for short procedures, one-lung ventilation was unnecessary and not without complications. They also had upper respiratory tract infection. Therefore, two-lung ventilation was used with a PLMA. Use of low tidal volumes with increased respiratory rate ensured that airway pressures remained lesser than leak pressures for PLMA.Even if the procedures are of a longer duration or intra-operatively, if visualization is inadequate, an Arndt bronchial blocker may be inserted through the PLMA as shown by Li et al. for paediatric scoliosis correction surgery.[8]
CONCLUSION
We conclude that the need for one-lung ventilation and the airway device used should be highly individualized according to the surgical need, the procedure undertaken and the patient's pulmonary status.