Options of Introduction
There are many ways the fiberoptic bronchoscope can be introduced. An awareness
of these alternatives is important. Each method has its own unique advantage. The
anesthetic procedure will vary depending on the method you have selected.
- Transnasal:
The transnasal method is by far the best approach. The introduction of scope must be more
by feel, and not by vision. It is aesthetic. Patients can swallow secretions easily.The
disadvantage is the difficulty beginners seem to have in introduction of the scope. Nose
bleeding occurs due to injury. I avoid this approach in patients at high risk for
bleeding.
Cocaine used as a topical anesthetic is ideal for the transnasal approach. The
mucosa shrinks, permitting easier passage and the bleeding is minimized by
vasoconstriction.
- Transoral:
- With a mouth bite: Transoral with mouth bite: This is the current method I use. A
mouth bite is slipped into position for the patient to bite on and affixed with tape. This
method protects accidental injury to the bronchoscope and is tolerated well by the
patient.
- Through a soft ET tube: Transoral with soft ET tube: Initially, I used to adopt
this technique. The soft endotracheal tube is slipped over the bronchoscope as a sleeve.
The scope is then introduced directly into the trachea. The endotracheal tube is slipped
into the trachea.
The bronchoscope is withdrawn and a mouth bite is
placed about the endotracheal tube for protection and taped in place. This permits removal
and re-insertion of the scope conveniently. This is especially useful in training fellows.
The secretions around the pharynx can be a problem and patients often develop a
sore throat with this method.
In patients who have precarious pulmonary status, a cuffed endotracheal tube has
been substituted for a soft endotracheal tube. If ventilatory support becomes necessary,
it becomes easy to provide.
- Through a rigid bronchoscope: The fiberoptic bronchoscope is introduced after
insertion of a rigid bronchoscope. This method used to be practiced by thoracic surgeons
in the early days. With increasing familiarity and experience with fiberoptic scope, this
method of introduction of the fiberoptic bronchoscope is now rarely done.
- Transtracheal:
- Patient on a ventilator: When patients are on a ventilator, once can perform a
bronchoscopy through a portex adapter. The adapter permits insertion of a bronchoscope and
performance of the procedure without the interruption of continuous mechanical
ventilation.
- Patient with a tracheostomy: If the patient has a tracheostomy, it is extremely
easy to introduce the bronchoscope through the tracheostomy stoma. Instill local
anesthetic through the stoma and proceed with bronchoscopy.
The size of the bronchoscope and the endotracheal tube are important
considerations. You need a size 8 tube and larger with a bronchoscope 5.5 mm in diameter.
With smaller tubes, the peak pressures developed by the ventilator become excessive. The
risk of pneumothorax becomes higher.
Prior to bronchoscopy, you should increase the oxygen concentration to 100% and
increase the tidal volume to account for a leak. The procedure should be done
intermittently.
If the endotracheal tube is smaller than 8 mm, we have three options:
Reintroduce a larger ET tube, use a pediatric bronchoscopy or try introducing the
bronchoscope along the side of the ET tube.
References:
- Barret, CR. Flexible fiberoptic bronchoscopy in the critically ill patient. Chest
73:746-9, 1978.
- Feldman, NT, et al. An alternate method for fiberoptic bronchoscopic examination
of the intubated patient. AARD 111:562-3, 1975.