endosonographic procedures , including endobronchial ultrasound ( ebus)-guided transbronchial needle aspiration ( tbna ) and endoscopic ultrasound ( eus)-guided fine - needle aspiration ( fna ) are routinely used for accessing mediastinal and hilar lymph nodes and masses . in patients with hypoxemia , excessive cough , raised intracranial tension , or with central airway obstruction due to lesions compressing the trachea ; eus - fna may be safer than ebus - tbna as it employs the esophageal route .
however , patients with central airway obstruction requiring mechanical ventilation are often managed in respiratory care units , where eus - fna may not be available . in this situation , the pulmonologist can use the ebus scope for performing a technique known as eus ( with an echobronchoscope)-guided fna ( eus - b - fna ) .
this procedure has been reported to have a good diagnostic performance in the evaluation of mediastinal lesions .
herein , we describe a patient with respiratory failure due to airway obstruction by a mediastinal tumor , who was being mechanically ventilated .
a 50-year - old man presented to the emergency department with stridor of 1-week duration .
there was a significant reduction in appetite and he had lost 5 kg of his body weight . on admission to our facility ,
physical examination revealed an afebrile patient with a heart rate of 120 beats / min , respiratory rate of 38 breaths / min , and blood pressure of 80/50 mmhg .
contrast - enhanced computed tomography ( ct ) of his chest revealed the presence of a mass in the subcarinal region encasing the lower trachea and main bronchi and consolidation in the right upper lobe [ figure 1 ] .
mass in the subcarinal region encasing both the main bronchi and causing compression of the pulmonary vessels the patient was intubated with an endotracheal tube ( 7.0 mm internal diameter ) and mechanically ventilated .
he was initiated on intravenous co - amoxiclav ( 1.2 g thrice a day ) .
however , the patient could not be weaned off the ventilator over the next 5 days . on the 6 day , eus - b - fna of the subcarinal mass was performed .
cytological examination showed loosely cohesive clusters and dispersed population of small - sized tumor cells with hyperchromatic nuclei showing focal nuclear molding suggestive of small cell carcinoma of the lung [ figure 2 ] .
photomicrograph of the aspirate from the mediastinal mass obtained by endoscopic ultrasound ( with an echobronchoscope)-guided fine - needle aspiration showing loosely cohesive clusters and dispersed population of small - sized tumor cells with hyperchromatic nuclei showing focal nuclear molding suggestive of small cell carcinoma .
background shows nuclear debris ( h and e , 40 ) the final clinicoradiological stage was iiib ( t4 n3 m0 ) , but the patient had a poor performance status ( eastern cooperative oncology group score of 4 ) .
placement of a metallic tracheobronchial y - stent was considered but was not performed as the patient 's legal representative refused consent .
chemotherapy with cisplatin 100 mg ( 85% of 60 mg / m of body surface area [ bsa ] ) and irinotecan 160 mg ( 90% of 100 mg / m of bsa ) were administered . after a week
, the patient was successfully weaned off the ventilator and was discharged to home care .
however , the disease progressed and the patient succumbed to his illness 3 months after the diagnosis .
the index case illustrates the utility of eus - b - fna in accessing mediastinal lesions in mechanically ventilated patients , where ebus - tbna may be technically difficult or not feasible .
a diagnosis of advanced lung cancer was made and the administration of palliative chemotherapy enabled liberation from mechanical ventilation .
mediastinal or hilar lesions in critically ill patients can be approached endoscopically by the pulmonologist through the airway using tbna that can be performed with or without ebus guidance . both conventional and ebus - guided
tbna have been described in patients with respiratory failure , who are mechanically ventilated through an endotracheal tube ; however , they are not performed frequently .
this is because a small - sized endotracheal tube does not allow the entry of the echobronchoscope ( insertion tube diameter , 6.9 mm ) .
further , as the procedure requires a few minutes , significant hypoxia may occur in patients with a poor respiratory reserve .
the index patient was being ventilated with a small - sized endotracheal tube ( internal diameter of 7.0 mm ) and he had significant hypoxemia .
eus may be useful in such patients as the access is through the esophagus , thus not compromising ventilation .
eus offers access to lymph node stations 5 ( para - aortic ) , 8 ( paraesophageal ) , and 9 ( pulmonary ligament ) in addition to stations 4 l ( left lower paratracheal ) and 7 ( subcarinal ) .
however , this procedure is usually performed by gastroenterologists and many respiratory intensive care units may not have easy access to this technology , especially at the bedside .
eus - b - fna , which is performed by the pulmonologist with the same echobronchoscope used to perform ebus - tbna overcomes this limitation .
moreover , the introduction of the ebus scope ( 6.9 mm in diameter ) may be easier than the introduction of the eus scope ( 1214 mm in diameter ) in patients who also have esophageal narrowing . due to these reasons ,
ct - guided fna was not employed as it would have entailed a high risk of pneumothorax due to the central location of the mass .
a systematic review of the pubmed database using the search string : ( ebus or  endobronchial ultrasound  or 
transbronchial needle aspiration  ) and ( icu or  intensive care unit  or  critically ill  or
 mechanical ventilation *  or  mechanically ventilated  or intubated or  endotracheal tube  ) yielded 10 reports ( 62 patients ) of endoscopic interventions ( conventional tbna , ebus - tbna , eus - fna , or eus - b - fna ) for mediastinal / hilar lesions in critically ill patients [ table 1 ] .
forty - six patients could be diagnosed successfully resulting in an overall yield of 74.2% ; there were no major complications .
moreover , the diagnostic information obtained from the procedure led to a change in the treatment decision in most of these patients ( 49/62 ; 79% ) .
in our case , eus - b - fna allowed institution of appropriate chemotherapy and facilitated liberation of our patient with advanced lung cancer from mechanical ventilation , an event not commonly encountered in clinical practice . published reports of endoscopic diagnostic interventions for accessing mediastinal / hilar lesions in critically ill patients
the index case demonstrates that eus - b - fna is a valuable addition to the armamentarium of the pulmonologist for diagnosing mediastinal lesions in critically ill patients , including situations such as respiratory failure , which preclude a diagnostic bronchoscopy and ebus - tbna .
 endobronchial ultrasound ( ebus)-guided transbronchial needle aspiration ( tbna ) is routinely used for accessing mediastinal lymph nodes and masses . 
 however , in patients with respiratory failure , who are being mechanically ventilated through an endotracheal tube , ebus - tbna may not be feasible due to several reasons . 
 in such patients , the esophageal route offers a useful alternative for accessing mediastinal lesions . 
 herein , we describe a 50-year - old man with a mediastinal mass , who was being invasively ventilated for respiratory failure . 
 endoscopic ultrasound ( with an echobronchoscope)-guided fine - needle aspiration was performed , which revealed a diagnosis of small cell carcinoma . 
 appropriate cancer chemotherapy resulted in successful liberation of the patient from mechanical ventilation . 
 we have also performed a systematic review of literature for reports of endoscopic diagnostic procedures for mediastinal / hilar lesions in critically ill patients . 
Introduction
Case Report
Discussion
Conclusion
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