Tracheal Stenosis In Pregnancy : Anesthetic Dilemma

Author Information

Patil YS*, Wajekar AS**, Patel RD***, Samant PY****.

(* Associate Professor, ** Assistant Professor, *** Professor, Department of Anesthesiology; **** Additional Professor, Department of Obstetrics and Gynecology, Seth G S Medical College & KEM Hospital, Mumbai, India.)

Abstract

We present the anesthesia management of a pregnant patient with acquired subglottic stenosis for elective lower segment caesarean section (LSCS) under spinal anesthesia with severe postoperative desaturation requiring emergency intubation and tracheal dilatation. Presence of tracheal stenosis during pregnancy significantly affects maternal and foetal oxygenation and ventilation making anesthesia management very challenging. Congestion and edema of the airway in pregnant patients combined with increased respiratory load can worsen the obstruction in such patients. The goals of anesthesia are avoiding maternal loss of airway, maintaining both maternal and fetal oxygenation and ventilation. Although the surgery was successfully managed with neuraxial anesthesia, the patient still remained at high risk of postoperative complications. Emergency airway management may be required at any stage in such patients and preparation for difficult airway should include keeping bronchoscopy, bougie and tracheal dilators, jet ventilation and tracheostomy ready. In some scenarios, femoro-femoral cardiopulmonary bypass may also be required.

Introduction

Pregnancy is considered as difficult airway  and failed intubation can give rise to catastrophic consequences. Presence of tracheal stenosis during pregnancy significantly affects maternal and foetal oxygenation and ventilation making anesthesia management very challenging.^[1–3] Post intubation tracheal stenosis affects 4-13% of adults in United States and 90% of them progress to chronic subglottic stenosis.^[4]

We present the perioperative anesthesia management of a pregnant patient with acquired subglottic stenosis for elective lower segment cesarean section (LSCS). Although the surgery was conducted under combined spinal epidural anesthesia, she had postoperative severe hypoxia necessitating emergency intubation and tracheal dilatation.

Case Report

A 24 year old primigravida with history of tracheal stenosis was posted for elective LSCS in view of cephalopelvic disproportion. During first trimester, she contracted pneumonia and acute respiratory distress necessitating endotracheal intubation for 8 days. 15days later she developed acute stridor. Flexible bronchoscopy done by ear-nose-throat (ENT) surgeons, at the time and again 3 months later showed grade III soft tracheal stenosis near 5^th tracheal ring with tracheal lumen of 0.5 cm which required tracheal dilatation with bougie. Elective tracheostomy was avoided since it was a soft stenosis responsive to tracheal dilatation. Currently, she had inspiratory stridor which increased in supine position and with effort tolerance of one flight. Her haemoglobin was 9.1 g%. All other routine investigations were normal. Standard monitors including electrocardiography, automated blood pressure, pulse oximetry (SPO2) and end-tidal carbon dioxide were applied. Her pulse was 42/min with blood pressure 130/70 mm hg and SPO2 98%. Left uterine displacement was maintained. Combined spinal epidural (CSE) anesthesia was planned. ENT surgeon was present in the operating room throughout procedure. Difficult airway preparation included laryngeal mask airways (LMA) and different sizes of endotracheal tubes, Frova’s ventilating and intubating bougie, transtracheal jet ventilation, rigid bronchoscope with tracheal dilators of various sizes and tracheostomy tubes. Epidural catheter was inserted at L2-3 space and bupivacaine 0.5% 2cc was injected intrathecally in L3-4 space with a 25G spinal needle. T6 level was achieved. A healthy neonate with a good APGAR score was delivered. The intraoperative period was uneventful. No other sedatives were given. Post procedure 30mg tramadol diluted in 10cc was injected epidurally. Paracetamol 1g IV was given 8hrly. She was shifted to recovery room with oxygen by mask.

Four hours after surgery, she had hypotension up to 80/60 mm hg and desaturation up to 88%. Ventimask with reservoir bag at 8L/min brought her saturation up to 92%.  Two packed cell transfused since she appeared pale and blood loss was around 900ml. She was shifted to intensive care unit (ICU) in propped up position. She maintained 100% saturation with overnight continuous positive pressure ventilation. After chest physiotherapy in ICU, she probably had loosened secretion which obstructed the stenotic airway and she suddenly desaturated up to 67% with peripheral cyanosis. She was intubated with 5.5mm endotracheal tube. Her arterial blood gases 1 hour later were pH 7.098, pCO2 83.7, pO2 161.9, HCO3 18.3 and Sao2 98.4%. Emergency bronchoscopy and tracheal dilation under intermittent apneic technique with jet ventilaton under total intravenous anesthesia (TIVA) was done. After successfully dilating with 26 size tracheal bougie, she was intubated with 7mm endotracheal tube. She was electively ventilated and weaned off and extubated after 12 hours. She was shifted to ward on day 3 and discharged on day 8.

Discussion

Difficult intubation can lead to significant airway related injuries leading to adverse maternal and fetal outcomes.^[5] Congestion and edema of the airway in pregnant patients combined with increased respiratory load can worsen the obstruction in such patients.^[1] Mother and foetus are at high risk of impaired oxygenation and ventilation. Definitive treatment with stents for tracheal stenosis are licensed only for malignant conditions.^[1,6] Surgical morbidity and mortality associated with tracheal reconstruction prevents its use in benign stenosis. Generally such tracheal stenosis are managed with serial tracheal dilatations. Radiological evaluation with computed tomography or lateral neck x-ray was avoided in our patient due to her pregnancy and as prior bronchoscopy reports were available.

The goals of anesthesia are avoiding maternal loss of airway, maintaining both maternal and foetal oxygenation and ventilation. Preoperative bradycardia in the supine position can be attributed to inferior vena cava compression, relieved by left uterine displacement. Although the surgery was successfully managed with neuraxial anesthesia, patient still remained at high risk of postoperative complications. As occurred in our patient, any kind of airway irritation such as coughing or instrumentation can precipitate catastrophic complete airway obstruction.^[6] Ventilation through 5.5 mm endotracheal tube led to severe hypercarbia and emergency tracheal dilatation with bronchoscopic passage of a large size tube was required under TIVA.

Common causes of tracheal stenosis are inflammatory diseases, benign and malignant tumours, collagen vascular diseases etc. Prolonged intubation is one of the leading causes of acquired tracheal stenosis with incidence of almost 4-13% intubated adults.^[4] The tracheal wall in contact with the endotracheal cuff is generally the site of this stenosis.^[6] Local inflammation and mucosal ischaemia  near cuff leads to ulceration, granulation tissue, tracheal chondritis and fibrotic stenosis.^[5]  The site of tracheal stenosis is very important since upper stenosis may be treated with an endotracheal tube passed beyond the cords. But mid-level tracheal stenosis may require unilateral or differential bronchial intubation or even cardiopulmonary bypass.^[6]

If surgery demands, then elective intubation can be attempted in topical airway anesthesia or bilateral cervical plexus block.^[6,7] Salama et al reported a case of pregnant woman with tracheal stenosis whose stenotic area was preoperatively dilated by a balloon with fibre optic bronchoscopy under local anesthesia.^[2] Kuczkowski et al performed preoperative elective tracheostomy under local anesthesia in the 36th week of pregnancy which was kept till the end of her pregnancy.^[8] We did not perform elective tracheostomy in our patient, because ENT surgeons felt she can undergo tracheal dilatation if need arises. Parsa et al and Sutcliffe et al described the general anesthesia management for bronchoscopic dilatation of stenotic airway in pregnancy.^[1,3] Laryngeal mask airway is a valuable tool for ventilation and passing a guidewire, allowing flexible bronchoscopy.^[6]

Conclusion : Airway management of pregnant patients with critical tracheal stenosis can be tricky and the key step is prevention of loss of airway, maintenance of adequate oxygenation and ventilation. Although regional anesthesia is a boon in such patients for conduct of anesthesia, need for emergency airway management must be kept in mind. Multidisciplinary approach along with availability of experienced personnel and difficult airway equipments at hand ensures successful outcome.

References

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Citation

Patil YS, Wajekar AS, Patel RD, Samant PY. Tracheal Stenosis In Pregnancy : Anesthetic Dilemma. JPGO 2015. Volume 2 No. 8. Available from: http://www.jpgo.org/2015/08/tracheal-stenosis-in-pregnancy.html