Massive hydrothorax following supracostal percutaneous nephrolithotomy.

Abstract

Sir, Percutaneous nephrolithotomy (PCNL) is used commonly for the treatment of large renal and upper ureteric calculi. We report a 30-year-old female who developed a massive hydrothorax diagnosed postoperatively following PCNL for left renal calculus. Standard anaesthesia with controlled ventilation was administered. PCNL was performed in the prone position with a left supracostal (between 11th and 12th rib) approach. Multiple attempts were required to reach the superior calyx. Intraoperatively the patient remained haemodynamically stable. The procedure lasted 120 min; blood loss was ≈ 400 mL. Following extubation the patient was comfortable and haemodynamically stable with oxygen saturation (SpO2) 98% on 40% oxygen. After 30 min, the patient complained of breathing difficulty. She was tachypnoeic, with SpO284% (O2 5 L/min). Air entry was absent in left hemithorax, with dullness on percussion. Chest radiograph revealed left hydrothorax [Figure 1a]. An intercostal chest drain with underwater seal was inserted in the left 5th intercostal space. Haemorrhagic fluid (850 mL) was drained. Patient experienced difficulty in breathing following rapid pleural decompression. Continuous positive airway pressure was given by face mask with 100% oxygen for 20 min. Thereafter, she was asymptomatic, SpO2 was 100% and arterial blood gas analysis was normal. Repeat chest radiograph 24 h later showed lung expansion [Figure 1b]. The drain was removed on the 3rd postoperative day. The patient was discharged on the 6th postoperative day.Figure 1: Postoperative chest radiograph showing (a) opacity of left hemithorax and (b) re-expansion of the lung at 24 hAnaesthetic challenges during PCNL include the potential for fluid absorption, dilutional anaemia, hypothermia, blood loss, injury to adjacent organs and pleural space violation.[12] The renal calyceal system can be accessed via a subcostal or supracostal route. The supracostal access (above the 12th or 11th rib) is commonly used as it provides direct access to the upper, middle and lower calyx and the upper ureter.[2] However, this approach can potentially damage the lung and pleura resulting in hydrothorax, pneumothorax or hydropneumothorax.[1] Pleural injury can be avoided by supracostal puncture over the most lateral portion of the 12th rib as this portion of the diaphragm is not covered by a pleural reflection.[3] The intercostal puncture is made in the lower half of the intercostal space to avoid injury to intercostal vessels.[4] The supracostal approach requires coordination with the anaesthesiologist to control ventilation. The needle is passed through the retro-peritoneum and diaphragm during complete exhalation to prevent injury to the lung. The passage of the needle through the renal parenchyma to the collecting system is done during deep inspiration (the kidney gets displaced downwards). An Amplatz sheath is used to maintain low-pressure irrigation that can reduce the risk of pleural effusion and extravasation.[4] Reasons for development of hydrothorax are three-fold: (a) Inadvertent entry into the pleura; (b) inadequate tamponade of the nephrostomy tract combined with inadequate drainage of the kidney after the puncture; and (c) failure to seal the tract with a working sheath during stone removal.[5] Hydrothorax and pneumothorax can be difficult to identify during PCNL. Intraoperatively, a decrease in SpO2 and a significant increase of airway pressure is suggestive of hydrothorax. The diagnosis can be confirmed with a chest radiograph; with the patient in the prone position, fluid can be seen tracking along the lateral borders of the chest cavity and compressing the ipsilateral lung.[3] In the immediate postoperative period, pleural injury presents clinically with poor SpO2, dyspnoea and tachypnoea.[4] A postoperative chest X-ray is mandatory. The treatment of hydrothorax depends on patient symptoms and its extent.[4] Patients with no or mild symptoms and minimal effusion are managed conservatively; those with significant symptoms and large pleural effusion need intercostal drainage. Re-expansion pulmonary oedema, an uncommon complication following drainage of a pneumothorax or pleural effusion, presents clinically as cough, chest discomfort and hypoxemia. Risk factors include young age, long duration of lung collapse and rapid re-expansion. Treatment is largely supportive (oxygen supplementation, noninvasive and invasive ventilation). A high index of suspicion should be maintained when PCNL is performed with a prolonged operating time, multiple tracts and supracostal access. The access puncture should be performed in complete lung deflation and ventilator stand-still in coordination with the anaesthesiologist to minimise the risk of pleural injury. A chest X-ray should be performed promptly in symptomatic postoperative patients to exclude intrathoracic injury. Hydrothorax, haemothorax and/or pneumothorax sustained during PCNL may necessitate chest tube placement.