The Critical Airway

Abstract

Imagine you are asked to evaluate the airway of a 4 months old with noisy breathing. Surrounded by anxious parents and helpless staff, you find an emaciated infant with biphasic stridor and suprasternal and subcostal retractions. He has been feeding poorly and intermittently cyanotic for several days. The first thing you must remember not to do is panic. The critical airway can be safely and effectively managed when a composed surgeon follows a sensible thought process and conducts a directed work up as part of a multidisciplinary care team.

Appendices

Summary Points

Technical Points

In a child with noisy breathing, one must consider: the acuity of the child’s airway and to establish whether the noise is stridor vs. stertor.

A bedside flexible laryngoscopy can help establish the status of the nasopharynx, base of tongue, supraglottis and vocal fold mobility or pathology. More distal lesions cannot be reliably seen during this type of endoscopy in a young child.

Plain films and airway fluoroscopy can give clues, but are not diagnostic for airway pathology.

A swallowing study may be used in conjunction with an airway fluoroscopy to rule out a vascular ring or sling.

MLB are the gold standard for evaluation of stridor.

Always communicate the plan with the anesthesiologist, establish the airway, and do not remove the anterior cricoid cartilage unless it is clear that a CTR is to be performed. Avoid a laryngofissure unless absolutely necessary for posterior exposure. Avoid vocal fold injury.

Avoid a T-tube in young patients <4 years old and in patients with airways that would not accommodate an 8 mm T-tube.

Preoperative cultures to rule-out MRSA and pseudomonas in the airway.

Patients should undergo a multi-disciplinary evaluation: otolaryngology, pulmonology, gastroenterology, speech pathology. When indicated: genetics, general surgery and critical care.

Editor’s Comment

Few situations are as terrifying as the child with acute compromise of the airway. As always, a calm and systematic approach is best. Mask ventilation should be attempted first while preparations are made for endotracheal intubation, temporary airway, and tracheostomy, usually in that order. In the trauma setting, neutral position of the neck must be maintained. Needle cricothyroidotomy with jet insufflation is an excellent option but care should be exercised in that excessive pressure, especially in an infant, can cause pneumothorax and life-threatening decompensation. Even in the setting of oral injury or bleeding, one brief attempt at orotracheal intubation – by the person with the most experience – is usually reasonable.

Emergency tracheostomy is rarely indicated in a child. It is truly a very delicate operation. The lack of adipose tissue and the presence of clean planes of dissection in some ways make it easier; but the small caliber of the trachea greatly increases the risk of iatrogenic injury. As always, meticulous technique, good lighting, and proper instrumentation are critical. All maneuvers should be deliberate and never forced. A trap-door tracheal incision, popular in adults, should not be used in children and, of course, it is important to avoid injury to the cricoid cartilage. If a tracheostomy tube is not available, an appropriate size cuffed or uncuffed endotracheal tube works just as well. In elective cases, some prefer to create a true fistula by suturing the edge of the tracheotomy to the skin.

Costal cartilage harvest is a straightforward procedure that involves removing a portion of one of the lower rib cartilages. Ribs seven through nine are often fused near the sternum, providing a wider graft, if needed. Although a graft can be taken from the costal margin, this can cause discomfort and a noticeable cosmetic defect. It is important to know exactly what size graft the airway surgeon needs for that particular patient. Most ask for a piece that has perichondrium on one side, allowing preservation of the posterior perichondrium; however, some request that there be perichondrium on both sides. This almost always results in violation of the pleura and pneumothorax, which should be evacuated with a soft rubber catheter under water seal or displaced with saline. Rarely is a chest tube required. Typically, the surgeon will sterilely prepare the neck and the chest as a unit and begin the airway portion of the operation. After determination of the size of the graft that is needed, a second surgeon is sometimes called on to harvest the graft. A small transverse incision is made over the lower rib cartilages, the pectoralis muscle fibers are separated, (not divided), and the site for the graft is marked with cautery. The cartilage can be incised with a scalpel and peeled off the posterior perichondrium. If both perichondrial surfaces are needed, the pleura can be attempted to be peeled off the perichondrium, but this is rarely completely possible. Injury to the intercostal vessels or internal mammary artery can result in significant bleeding. Inadvertent lung injury is rare but necessitates placement of a chest tube.

Differential Diagnosis

Laryngomalacia

Vocal fold paralysis

Subglottic stenosis

Subglottic cyst

Tracheal stenosis

Tracheomalacia

Bronchomalacia

Nasal obstruction

Diagnostic Studies

MLB is gold standard

Plain radiograph

Airway fluoroscopy

Barium swallow

Modified barium swallow

Functional endoscopic evaluation of swallowing (FEES)

Parental Preparation

It might not be possible to take away the tracheostomy at this stage of the repair.

Decision regarding laryngotracheal reconstruction vs. CTR might need to be made intra-operatively.

Harvest of rib artilage graft might be necessary.

There is a risk of postoperative dysphagia and aspiration.

Preoperative Preparation

Communication with anesthesiologist and critical care team

Bronchoscopy table set up, camera checked and white-balanced

Informed consent

Rule out tracheal pathogens (MRSA, Pseudomonas) in child with a tracheostomy tube

Technical Points

Have the same approach to the bronchoscopy; know how to manipulate the camera and bronchoscope while performing the procedure.

Vertical incision for tracheostomy.

Horizontal cervical skin incision at level of cricoid for reconstruction.

Avoid horizontal tracheal incision and removal of cricoid plate unless the need for a CTR is confirmed.

Avoid CTR if the stenosis involves the vocal folds.

Have a bougie in the esophagus for resections.

Tension-free anastomosis is critical to the success of a resection.