Foreign body removal with repair of iatrogenic tracheo-bronchial tear repair: An anesthetic challenge.

Foreign body aspiration into the airway is common in the pediatric age group and its anesthetic management is a challenge. Iatrogenic tracheo-bronchial injury further worsens the situation. Flexible pediatric fiberscope is the gold standard for securing the airway in cases of airway injury. We present a case of a 7-year-old girl who presented to the hospital with signs and symptoms of foreign body aspiration and suspected tracheo-bronchial tree injury. The impacted foreign body was removed by rigid bronchoscopy and the presence of a tracheo-bronchial tear was confirmed. To repair the airway tear, thoracotomy was planned necessitating one lung ventilation. A pediatric flexible fiberscope was not available, so left endobronchial intubation for one lung ventilation was done with the help of an airway exchange catheter using a rigid bronchoscope as a conduit. Subsequent intra-operative and post-operative period were uneventful.

Introduction

Aspiration of foreign body (FB) into the airway is a common cause of accidental deaths in children. We report the successful management of a patient who had aspirated a FB and subsequently sustained a tracheobronchial injury.

Case Report

A 7-year-old girl developed severe cough with respiratory distress following aspiration of a FB. Repeated unsuccessful attempts at rigid bronchoscopy were made for removal of the FB in a local hospital. Consequent to the attempts tracheobronchial injury was suspected and the patient was transferred to our hospital. On arrival in our emergency room, child was conscious, oriented, tachypneic (RR=50/min), and with a heart rate of 140 beats per minute. The child also had a right sided chest tube with air leak. There was decreased air entry on the right side of chest and there was subcutaneous emphysema over the right hemithorax. Arterial blood gas (ABG) analysis showed pH 7.415, pO2 63.7, pCO2 27.9, SO2 90.8, HCO3 17.4, and BE –5.2. Chest X-ray was suggestive of right-sided pneumothorax. The child was prepared for an emergency rigid bronchoscopy followed by thoracotomy for airway repair. After obtaining written informed consent, she was shifted to the operating room. Electrocardiography, non-invasive blood pressure, and pulse oximetry monitors were attached and baseline vitals recorded. The patient was premedicated with glycopyrollate 0.01 mg / kg intravenous (IV), ranitidine 1 mg/kg IV, metoclopramide 0.1 mg/kg IV, and fentanyl 2 mcgm/kg IV. Anesthesia was induced with thiopentone sodium 5 mg/kg IV. Two breaths with bag and mask were given to check if the patient could be ventilated after which succinyl choline 1.5 mg/kg IV for neuromuscular blockade. Laryngoscopy was done to aid insertion of a pediatric ventilating rigid bronchoscope (ED 5.7 mm, ID 4.9 mm). Anesthesia was maintained with sevoflurane and 100% oxygen and vecuronium for relaxation. The patient was ventilated manually through a Jackson-Rees circuit connected to the ventilating side-arm of the bronchoscope with low tidal volumes at high rate (40-50 breaths/min) and gas flow was adjusted to compensate for the leak around the bronchoscope and through the chest drain.

An 1.5 cm tear at the carina extending into right main stem bronchus and an impacted FB in right main bronchus were visualized. After the removal of FB (tamarind seed), right thoracotomy for repair of tear was planned for which the surgeons requested right lung deflation with use of one lung ventilation (OLV). Non-availability of a pediatric flexible bronchoscope in the emergency operation theatre made endobronchial intubation for OLV difficult. The only available method for OLV was selective left-sided endobronchial intubation but an attempt at blind endobronchial intubation could potentially worsen the airway injury. A safe way to intubate the left mainstem bronchus was innovated by asking the surgeon to place the tip of the rigid bronchoscope in the left main stem bronchus under direct vision. An airway exchange catheter (14 Ch, 50 cm) was introduced using the bronchoscope as a conduit. After the removal of the bronchoscope, an uncuffed endotracheal tube of 5.5 mm ID was threaded over the airway exchanger and fixed at 24 cm at the angle of the mouth. Left endobronchial intubation was confirmed clinically.

Anesthesia during thoracotomy was maintained with 50% oxygen in N2O and sevoflurane with adequately spaced IV top ups of fentanyl and vecuronium. Adequacy of ventilation was clinically gauged by chest auscultation and looking for rise of left hemithorax with each breath. Pulse oximetry, capnography, and repeated ABG provided an objective assessment of the adequacy of ventilation. After the repair of the tear, the endotracheal tube was gradually withdrawn to the mid-tracheal level and bilateral lung inflation with no air leak was confirmed. A gentle suctioning of trachea was done to remove any blood in trachea, but only minimal bleeding was seen. Apart from two brief episodes (<45 s) of hypoxia (SpO2 < 60%) during removal of the FB, intraoperative period remained uneventful. ABG at this point showed: pH 7.307, pO2 105.3, pCO2 48.9, SO2 98.9 HCO3 23.9, and BE –2.5. Local anesthetic was instilled under direct vision by the surgeon, through the intrapleural catheter, for postoperative analgesia. Perioperative steroid and bronchodilator therapy was given. Decision to extubate the trachea in the immediate post-operative period was taken. Neuromuscular blockade was reversed with neostigmine (0.05 mg/kg) and glycopyrrolate (0.01 mg/kg) IV and trachea extubated. The patient was sent to ICU for observation. The postoperative period remained uneventful and the patient was discharged on the 10th postoperative day.

Discussion

Inhaled FB remains a significant cause of morbidity and mortality in young children. Rigid bronchoscopy is the most suitable procedure for its removal.[1] Rare complications of bronchoscopy like airway edema, perforation, or scarring have been documented.[2] Several anesthetic techniques for managing FB aspiration have been described, but there is no consensus regarding the optimal technique. Spontaneous ventilation was popular before the mid 1990s,[3] whereas more recently, reports in favor of controlled ventilation have appeared.[4] Chen et al.[5] found that use of spontaneous ventilation increases risk of intraoperative hypoxia.

In the case of airway trauma, inhalational anesthetic induction and spontaneous ventilation is considered to be safe as intermittent positive pressure ventilation (IPPV) may cause massive surgical emphysema in patients in whom there is no communication between the airway rent and the pleural space. In patients with communication between the airway rent and the pleural space, most of the delivered breath may be vented into the pleural space[6] leading to a tension pneumothorax. We preferred IPPV with low tidal volume and high respiratory rate as rigid bronchoscopy was done before the repair and bucking or movement during bronchoscopy could augment airway injury. The presence of a chest drain provided protection against tension pneumothorax. IPPV in the presence of a broncho-atmospheric fistula has been used in the past. Jacob and Sen[7] deliberately created broncho-atmospheric fistula (Malecot catheter placed in the cystic cavity having a large bronchial communication was connected to an underwater seal) in a case of pulmonary hydatids. A broncho-atmospheric fistula does not pose a problem during spontaneous ventilation but excessive air leak can occur during IPPV. This can be managed by increasing the airflow resistance through the tract by raising the water level in the water seal drainage bottle. In our case, the water level in the water seal drainage was probably providing enough resistance to allow the ventilation. In cases of airway injury, ventilation with low tidal volume, and high rate prevents creating excess airway pressure and minimizes the leaks.[8] Effective mechanical ventilation in the case of bronchopleural fistula can be accomplished by using maneuvers that reduce the airway pressure, fistula flow, and loss of tidal volume which include: Limiting the amount of peak-end-expiratory pressure used during ventilation; limiting the effective tidal volume; and shortening the inspiratory time.[9] We tried to do the same in our case.

Prasanna et al.[10] preferred manual ventilation, in the case of tracheal injury, as it provides a breath to breath monitoring to airflow resistance. With the advent of new and improved ventilators, mechanical ventilation may be preferred. We opted for manual ventilation due to non-availability of a suitable ventilator in our operating room.

Tracheal intubation in patients with intra-thoracic tracheobronchial injuries is best achieved under vision, using a fiberoptic bronchoscope, to ensure that the tracheal tube does not leave the trachea at the site of rupture or increase the damage at the site of injury.[6] Recommended methods of OLV in children are balloon-tipped bronchial blockers, Univent tubes, double lumen tubes (DLT), and single lumen endotracheal tube.[11] A DLT cannot be used in a small child. Endobronchial blockers could not be used as the bronchus to be blocked was injured. The only option remaining was selective endobronchial intubation of the contra-lateral bronchus under vision. We used the rigid bronchoscope to achieve a safe left endobronchial intubation as a flexible fiberoptic bronchoscope was not available.

After surgery, early extubation is recommended in cases of tracheobronchial injury to avoid additional complications caused by the tube, elevated endotracheal pressure during artificial ventilation or repeated suctioning.[12] We too preferred an early extubation.

To conclude, rigid bronchoscope, which is usually used for removal of inhaled FB, can be successfully used with an airway exchange catheter to achieve safe endobronchial intubation in special situations.