Use of intubating laryngeal mask airway in a morbidly obese patient with chest trauma in an emergency setting.

A morbidly obese male who sustained blunt trauma chest with bilateral pneumothorax was referred to the intensive care unit for management of his condition. Problems encountered in managing the patient were gradually increasing hypoxemia (chest trauma with multiple rib fractures with lung contusions) and difficult mask ventilation and intubation (morbid obesity, heavy jaw, short and thick neck). We performed awake endotracheal intubation using an intubating laryngeal mask airway (ILMA) size 4 and provided mechanical ventilation to the patient. This report suggests that ILMA can be very useful in the management of difficult airway outside the operating room and can help in preventing adverse events in an emergency setting.

Introduction

Management of difficult airway remains one of the most challenging tasks for the anesthesiologist. Anesthesiologists can come across difficult airway in patients for elective or emergency surgery in the operating room (OR) or outside the OR. Airway and ventilatory procedures outside the OR are associated with a higher incidence of adverse events and a higher risk of mortality than similar events in the OR.[12]

Morbidly obese patients are at risk of difficult mask ventilation as well as intubation, and airway management is a major factor underlying morbidity and mortality related to anesthesia in such patients.[3] The intubating laryngeal mask airway (ILMA) may provide better conditions for achieving effective ventilation and tracheal intubation in such patients.[45]

Case Report

A 36-yr-old male presented to the surgery emergency after blunt trauma chest with chief complaints of chest pain, more on the left side, and difficulty in breathing. There was no history of vomiting, loss of consciousness, pain in neck or any bleeding from the ear, nose or throat. On examination, the patient was morbidly obese (body mass index 45 kg/m2), drowsy but arousable on verbal commands with Glasgow coma score 13/15. The pulse rate was 102/min, BP 108/70 mmHg and respiratory rate 36/min. Pulse oximetry showed oxygen saturation of 60% on room air and 80% on ventimask with FiO2 0.5. Chest examination revealed bony crepitus on the left side and subcutaneous emphysema all over the chest, extending up to the infraclavicular area. Arterial blood gas analysis (on ventimask) revealed pH 7.28, pCO2 38, pO2 50, HCO3 18.1 and SO2 80%. Chest X-ray showed bilateral multiple rib fractures and bilateral pneumothorax with left lower zone collapse. Cervical spine X-ray revealed no bony injury.

The patient had persistent hypoxemia despite bilateral intercostal drainage being in situ, and was shifted to the intensive care unit for mechanical ventilation. Quick airway examination revealed mouth opening of 2.5 cm, large tongue, heavy jaw, short and thick neck, thyromental distance less than three finger breadths and Mallampati score 4.[6] Difficulty in face mask ventilation as well as tracheal intubation was anticipated and, therefore, awake intubation was planned. Difficult airway cart was prepared, but fiberoptic bronchoscope was not available and tracheostomy was expected to be difficult. After explaining the procedure to the patient, xylometazoline nasal drops were instilled into both nostrils and a prelubricated nasopharyngeal airway was gently inserted, through which 100% oxygen supplementation was carried out by Bain circuit and movements of the reservoir bag with respiration observed. The oxygen saturation improved and the patient became more cooperative. Bilateral superior laryngeal nerve block and transtracheal block were given with 2 ml of 2% lignocaine each using an 18G intravenous (IV) cannula. The cannula sheath was left in situ to provide translaryngeal jet ventilation if needed and 10% lignocaine was sprayed over the tongue and oropharynx.[7] Direct laryngoscopy was attempted, which revealed Cormack Lehane (CL) grade IV[8] and an intubation attempt was unsuccessful. We then attempted blind nasal intubation, but 6.5 mm ID endotracheal tube (ETT) could not be negotiated through the nasal cavity. Subsequently, we gently inserted a size 4 ILMA and the patient tolerated it well. The cuff was inflated with 30 ml air and placement confirmed by movements in reservoir bag and capnography. A well-lubricated 8 mm ID ETT was passed, through the ILMA, without any difficulty. The patient was cooperative and coughed just once on placement of the ETT. After confirming the placement by auscultation and capnography, ILMA was gently removed while pushing the proximal end of the tracheal tube with the help of the stabilizing rod. The patient was sedated with IV midazolam 2 mg, propofol 100 mg and morphine 6 mg. Neuromuscular blockade was achieved with vecuronium 7 mg IV and controlled ventilation was carried out. The patient remained on mechanical ventilation for 7 days, following which tracheotomy was performed. He was sedated with midazolam and put on synchronous intermittent mandatory ventilation and was gradually weaned off from the ventilator after 21 days [Figure 1].

Figure 1

Morbidly obese patient with endotracheal tube in place

Discussion

The use of ILMA to achieve adequate oxygenation/ventilation and provide a conduit for intubation in difficult to manage airways has been proven.[9] According to the American Society of Anesthesiologists 2003 difficult airway guidelines, awake intubation is the gold standard in a difficult airway patient after trauma if the patient is cooperative.[10]

Frappier et al. demonstrated, in a study on 118 patients scheduled for bariatric surgery, that ILMA is an effective and safe ventilatory device and blind intubation guide in morbidly obese patients. The rate of successful tracheal intubation was 96.3% and the success rate was not different among patients with low-grade (CL-I, II) and high-grade (CL III, IV) views.[5] Awake intubation in the emergency department using ILMA has earlier been reported in a morbidly obese patient with acute respiratory failure.[11]

However, ILMA usage in difficult airways is limited in certain situations such as mouth opening less than 1.5 cm, increased risk of aspiration and suspected or known abnormalities in the supraglottic anatomy.[12] The “ramped” position, Bullard laryngoscope or awake fiberoptic intubation can be used in obese patients at high risk of difficult tracheal intubation. Other options in morbid obesity include the short handle laryngoscope, video laryngoscopic-guided intubations and LMA C-trach, but they may not be available in an emergency.[13] ILMA is more efficient in the morbidly obese patients than in normal patients, with fewer airway adjustments needed for establishing ventilation.[14]

The successful airway management of this morbidly obese patient with chest trauma suggests that use of ILMA may provide a viable and safe option for “awake” endotracheal intubation outside the OR. We also suggest that the ILMA can be well tolerated in minimally sedated patients who are breathing spontaneously and who have been appropriately prepared for this method of tracheal intubation.