Laparoscopic adrenalectomy in a post-pneumonectomy state.

Abstract

Sir, Post-pneumonectomy patients pose challenges in anaesthesia management. Oxygenation and ventilation changes due to the absence of one lung, age, associated systemic co-morbidities and absence of disease in other lung are important factors affecting the outcome after surgery.[1] A 44 years old female patient with no systemic co-morbidities was posted for laparoscopic adrenalectomy; she had undergone right pneumonectomy for adenocarcinoma of lung 4 months before [Figure 1]. She had received four cycles of chemotherapy (cisplatin, pemetrexed, aprepitant). On positron emission tomography scan, an enhancing nodular lesion involving left adrenal gland was revealed, possibly metastatic (17 mm × 17 mm × 14 mm).Figure 1: Chest radiograph post-pneumonectomyLaparoscopic left adrenalectomy was planned by the surgeon due to small size. Her breath holding time was more than 25 s. Two-dimensional echocardiogram (2DE) was normal, and exercise stress test was negative for inducible ischaemia. Pulmonary function tests (PFT) indicated early small airway obstruction. 24 h urinary metanephrines and vanillylmandelic acid levels were suggested due to the presence of the adrenal mass, resting heart rate of 120/min and blood pressure 150/90 mm Hg, to rule out phaeochromocytoma, which were found to be normal. General anaesthesia with controlled ventilation was planned. Monitoring consisted of electrocardiogram (ECG, leads II, V5, V6); oxygen saturation, end-tidal carbon dioxide (ETCO2), intra-arterial blood pressure (right radial artery) and central venous pressure (right internal jugular vein under ultrasound guidance). Partial pressure of oxygen and partial pressure of carbon dioxide on room air was 64 mm Hg and 38 mm Hg respectively. General anaesthesia was induced with injection midazolam 2 mg, injection fentanyl 150 μg, injection propofol 100 mg and injection atracurium 40 mg. Trachea was intubated with 7 mm cuffed endotracheal tube. Pressure controlled mode was used for ventilation targeting an expired tidal volume of 250–300 ml, a respiratory rate to target end ETCO2 between 35 and 40 mm Hg, a positive end-expiratory pressure of 5 cm of H2O and peak airway pressure <25 cm of H2O. Intraoperatively, 400 ml of Ringer's lactate solution was infused. Haemodynamics were stable intraoperatively. Trachea was successfully extubated by reversing neuromuscular blockade with 2.5 mg neostigmine and 0.5 mg glycopyrrolate at the end of 3 h. Injection paracetamol 1 g was infused prior to extubation for analgesia. Patient was observed in surgical intensive care unit overnight, shifted to ward next day and discharged on 3rd post-operative day. In presence of normal structural cardiac status, regional anaesthesia is well-tolerated but epidural anaesthesia is preferable as vasodilatation after a spinal anaesthetic may require additional fluid administration, which may not be well tolerated due to single lung that may lead to pulmonary oedema. Due to compensatory increase in pulmonary artery pressure and pulmonary vascular resistance after pneumonectomy, tachycardia, hypertension, hypercapnoea, acidosis, intubation and extubation response should be avoided in case of documented pulmonary hypertension. A low tidal volume (5–6 ml/kg) with increased respiratory rate to target the baseline CO2 using low inflating pressures prevents ventilation associated lung injury owing to hyperinflated lung parenchyma.[2] Pre-operative workup like PFT, resting 2DE, chest radiograph and arterial blood gas estimation on room air are essential tests in such patients. Exercise stress test, dobutamine stress echo should be reserved for specific patients and for major surgeries. Diffusion capacity of the lung for carbon monoxide is indicated in a patient with poor pulmonary reserve or in patients who are scheduled for cardiac or thoracic surgery. After pneumonectomy, the recommended total fluid intake is 1–2 ml/kg/h over 24 h.[34] Narcotics, paracetamol, regional anaesthesia, nerve blocks, non-steroidal anti-inflammatory drugs should be used for optimal pain relief. Incentive spirometry should be started pre-operatively.