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INTRODUCTION

Patients presenting with a large anterior mediasti-nal mass pose challenge to the anaesthesiologistdue to its complications ranging from dynamic air-way collapse to haemodynamic collapse on induc-tion of anaesthesia.1 At the extreme end of the dis-ease spectrum, however, anterior mediastinaltumours can be very difficult to manage in the peri-operative period, and the literature provides manyexamples of cardiorespiratory disasters and evendeath.2,3 Many of these publications relate to pae-diatric practice. Here we report the anaestheticdifficulties encountered in an adult patient whopresented to us with respiratory distress and wasposted for debulking of mediastinal mass.

CASE REPORT

A 35-year-old male presented with a one monthhistory of breathlessness and chest pain which wasmore in supine position. He was comfortable whilein the sitting and lateral position. After thoroughclinical and radiological evaluation, he was diag-nosed to have large anterior mediastinal tumourand was posted for emergency sternotomy anddebulking of the tumour. Review of the pre-op-erative CT imaging (Figure 1) revealed a 13 12

cm large mass in anterior mediastinum extendinginto the superior and middle mediastinum displac-ing the superior vena cava and right atrium andcompressing trachea and right main bronchus.Physical examination revealed that he was in res-piratory distress. Prominent non-pulsatile jugularvenous pulse was evident. Patient was shifted to

Case Report:Anaesthetic considerations in a patient with an anterior mediastinal mass

M. Madhusudan,1 J. Chaitanya,1 K. Vinay,1 N. Hemanth,1 P. Hemalatha,1 B. Vinod,2Aloka Samantaray,1 M. H. Rao1

Departments of 1Anaesthesiology, 2Cardiothoracic Surgery,Sri Venkateswara Institute of Medical Sciences, Tirupati

ABSTRACTWe report a 35-year-old gentleman who presented to us with respiratory distress. He was diagnosed to have a largeanterior mediastinal mass and was and posted for debulking of mediastinal mass. Immediately after intubation, airwaycollapsed and there was difficulty in ventilating the lungs, followed by drop in oxygen saturation. After sternotomy,oxygen saturation and airway pressures improved. In this report we discussed in detail about the successful anaestheticconsiderations for patients with large anterior mediastinal tumour including the management of airway obstruction.

Key words: Anterior mediastinal mass, Airway collapse, SternotomyMadhusudan M, Chaitanya J, Vinay K, Hemanth N, Hemalatha P, Vinod B, Samantaray A, Rao MH. Anaesthetic consid-erations in a patient with an anterior mediastinal mass. J Clin Sci Res 2013;2:225-8.

Corresponding author: Dr M.Madhusudan, Assistant Professor, Department of Anaesthesiology, Sri VenkateswaraInstitute of Medical Sciences, Tirupati, India. e-mail: drmadhu37@gmail.com

Received: 22 April, 2013.

Figure 1: CECT chest (saggital reconstruction) show-ing a soft-tissue mass measuring 12 13 cm showingminimal enhancement on intravenous contrast adminis-tration in the anterior mediastinum compressing the dis-tal part of trachea

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the operating room and was positioned in the lat-eral position. Apart from the routine AmericanSociety of Anaesthesiologist (ASA) standard moni-toring, left radial artery was cannulated with 20gauge cannula for invasive arterial pressure moni-toring and a 16 gauge peripheral intravenous can-nula was inserted in the lower limb under localanaesthesia. After 3 minites of pre oxygenation with100% oxygen, general anaesthesia was inducedslowly by inhalational administration of sevofluraneup to 8%. After check ventilation with face mask,endotracheal intubation (ETI) was facilitated withinjection vecuronium 0.1 mg/kg. Trachea was in-tubated with 7.5 mm plain endotracheal tube(ETT). We encountered severe resistance tomanual bag ventilation immediately after intuba-tion. We thought that it could be due to tracheal orright main stem bronchial compression by largeanterior mediastinal mass. We could not negotiatethe tracheal compression with a single lumen plainETT, so we did not think of using a double-lumenETT. The lungs could not be ventilated effectivelyto maintain arterial oxygen saturation by pulseoximetry (SpO2) of more than 90%. The patienthad one episode of bradycardia (heart rate <30beats per minute) and was successfully treated withintravenous injection of 0.6 mg atropine. But, theoxygen saturation did not improve. Consideringthe possibility of tracheal collapse, the surgeondecided to go ahead with emergency sternotomy.Immediately after sternotomy, the entire mediasti-num was filled with the tumour mass (Figure 2).There was a decrease in airway pressure and im-provement in oxygen saturation. The surgeon pro-ceeded for debulking of the tumour and only partof the tumour weighing around 350 mg wasdebulked and submitted for histopathology whichwas suggestive of primary mediastinal mixed ma-lignant germ cell turmour. Patient lost around 2.5liters of blood during the procedure and devel-oped hypotension which was managed with intra-venous fluids, blood transfusion and adrenalineinfusion. In view of short period of hypoxia forabout 5 min in the post ETI period and unstablehaemodynamic status, it was decided to ventilate

the patient electively in the post-anaesthesia careunit (PACU). Patient was extubated and was ad-ministered oxygen through a face mask during thefirst post-operative day. He had uneventful recov-ery, became haemodynamically stable after thatand was discharged from the PACU in the sec-ond post-operative day.

DISCUSSION

Airway and vascular collapse is a well-recognizedcomplication when patients with an anterior medi-astinal mass are managed surgically.1 The risk oflife-threatening or fatal airway obstruction orcardio-vascular collapse during induction of an-esthesia in patients with central airway obstruc-tion has been recognized since the 1970s.4 Overthe subsequent three decades, anaesthesiologistshave been aware of the high risk associated withgeneral anaesthesia in these patients. When pos-sible, in symptomatic patients with large anteriormediastinal masses, children with orthopnea andin more than 50% of tracheal compression gen-eral anaesthesia is avoided.5 If administered, it is

Figure 2: Intraoperative photograph showing mediasti-nal mass

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titrated stepwise induction with maintenance ofspontaneous ventilation and avoidance of neuro-muscular blockers is strongly advised. Only aftera successful trial of manual ventilation, the use ofneuromuscular blocking drugs should be consid-ered.

During anaesthesia lung volumes are reduced andbronchial smooth muscle relaxes, thereby increas-ing the compressibility of large airways.6 Partiallyobstructed respiration, which can occur during aninhalational induction, generates large negativepressures that tend to flatten further, a tracheaweakened by extrinsic compression. Muscularrelaxation, on the other hand, causes loss of chestwall tone and disrupts the forces of active airwayinspiration, thereby, further reducing external sup-port of the narrowed airway. Abnormal patternsof spontaneous breathing on emergence also cancause partial obstruction of breathing on inspira-tion.

General anaesthesia also results in reduction offunctional residual capacity (FRC) and alters res-piratory mechanics in a manner that favors airwaycollapse. In the supine position, the abdominalcontents tend to push the diaphragm cephalad into the chest, which reduces negative intrapleuralpressure and FRC. The compliance of the tho-racic wall is reduced in the anaesthetized state,further decreasing FRC by approximately 20%.7

Consequently, the chest wall expansion/lung-elasticrecoil equilibrium favors smaller lung volumes andclosure of susceptible airways especially in depen-dent areas of the lung. In the pathologic state, suchas in the presence of an intrathoracic mass, bothanatomic and physiologic perturbations may oc-cur. Mediastinal tumour invasion may compromisethe cartilaginous structural integrity, making the air-way more susceptible to direct tumour compres-sion. With tumour invasion, intrathoracic collapsewith forced expiration and reduced or lack of air-way dilatation during inspiration may occur. Simi-larly, partial upper airway obstruction in the rap-idly spontaneously breathing patient may generate

sufficiently negative intraluminal pressure to col-lapse the compromised segment.

In our case, the patient was posted for sterno-tomy and debulking of the tumour. Sternotomy isa very painful procedure which requires adequateanalgesia, deeper planes of anaesthesia and goodmuscle relaxation to spread the sternum. Wethought that spontaneous ventilation is difficult tomaintain, hence we decided to secure the airwaywith the help of neuromuscular blocking agents.We could maintain the ventilation with face maskbefore the tracheal intubation but were unable toventilate after ETI probably because of collapseof the trachea or bronchi distal to the ETT. Theonly option available to us at this stage in lieu offalling arterial oxygen saturation by pulse oxim-etry (SpO2) is to release this airway pressure bydoing an emergency sternotomy.

The other life saving maneuver at this stage couldbe a direct rigid bronchoscopy8 or to institute car-diopulmonary bypass (CPB).9,10 We could notexercise first option because of unavailability ofrigid bronchoscope. In experienced hands a rigidbronchoscope therefore can be advanced to stentthe airway.11 After initial assessment of the anatomy/pathology, it may be possible to stent11 the airwayfor resection surgery with an ETT or a double-lumen endobronchial tube placed under direct vi-sion into the most patent main bronchus. If thistechnique is not possible, ventilation can be main-tained down the rigid bronchoscope via a Venturiinjector, in the usual way, and anaesthesia can bemaintained intravenously. Once surgery has com-menced and the tumour has been lifted anteriorly,the degree of airway obstruction tends to lessen,and it may be possible to replace the broncho-scope with an endotracheal tube at some stage.

Though the second option was feasible in oursetup, it could not be implemented, as the casewas taken up on emergency basis and both theavailable heart lung machines were occupied atthat particular time for other open heart surgeries.The establishment of CPB by femoral cannulationsprior to induction of anaesthesia has been safely

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performed in adult patients. However, once air-way or cardiovascular collapse has occurred, itwill require at least 5-10 min to cannulate and es-tablish adequate circulation and oxygenation,10

even with a primed pump and a prepared team. Insuch a scenario, it is probable that a young patientcan be resuscitated but may suffer neurologicalinjury.12

This case report is an example of successful an-aesthetic management of patients with airway ob-struction. In patients at-risk of airway obstruction,whenever possible try to avoid general anaesthe-sia and if at all general anaesthesia is required,spontaneous ventilation should be maintained aslong as possible during and after induction of ana-esthesia. The decision to use neuromuscularblockers after induction and intubation may bedangerous in the high-risk patient with disease inthe distal trachea or main bronchus. Use of thesedrugs is strongly discouraged if the planned pro-cedure is solely diagnostic in nature and thus de-void of any meaningful tumour debulking. Reposi-tioning adult patients lateral or prone in compari-son with children may be less effective owing to amore ossified and developed chest wall. Shouldairway collapse occur, rigid bronchoscopy shouldbe immediately available to facilitate lifesaving ven-tilation. Lastly, if a high-risk patient requires a gen-eral anaesthesia, strong consideration should begiven to placement of the femoral cannulae withCPB machine stand-by before induction.

ACKNOWLEDGEMENT

We would like to extend our thanks to Dr P.Lakshmi, Assistant Professor, Department of Ra-diology, Sri Venkateswara Institute of MedicalSciences (SVIMS), Tirupati for her help with im-aging diagnosis.

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