Awake Fiberoptic Endobronchial Intubation

Paul S. Patane, MD, CPT, MC, USAR, Brence A. Sell, MD, and Michael E. Mahla, MD

E NDOBRONCHIAL intubation with double- lumen endotracheal tubes (DLT) has many

uses in the modern operating room including lung resection, esophageal surgery, anterior spi- nal fusions of thoracic vertebrae, and bronchopul- monary lavage. Even under the best of condi- tions, these intubations may be difficult. Fiberoptic bronchoscopy has simplified and as- sured proper placement of these endotracheal tubes. Because of the intense laryngeal and carinal stimulation produced by intubation with a DLT, this is usually performed after inducing general anesthesia.lW3 In the patient at risk for aspiration or with cervical spine disease, an awake intubation may be preferred. Two cases of awake fiberoptic DLT placement in patients with abnormal cervical spines are reported.

anesthesia, plus glossopharyngeal, superior laryngeal, and transtracheal nerve blocks. A 3.5mm fiberoptic broncho- scope was placed through the bronchial lumen of a no. 37 left-sided DLT and advanced, under fibroscopic guidance, orally to the vocal cords. The trachea was visualized, and the tube advanced into the left mainstem bronchus with its position verified by differential breath sounds and bronchos- copy. The patient tolerated the intubation without complaint, hemodynamic response, or recall. Anesthesia was induced with sufentanil, pancuronium bromide, and metocurine, and maintained with infusions of methohexital and sufentanil. At the conclusion of the procedure, the DLT was changed to a no. 7 oral endotracheal tube under direct visualization. This was thought to be safe because the airway was secure, the stomach empty, and the situation controlled. The patient tolerated the procedure well with no change in her somatosen- sory-evoked responses or neurologic examination from base- line. Six days later, the patient underwent posterior release, Luque rod instrumentation, and fusion without complication. She was discharged from the hospital 40 days after admis- sion.

CASE REPORT 1 CASE REPORT 2

A 65-year-old woman had dyspnea on minimal exer- tion. Two years before admission she had been in an automo- bile accident, sustaining a compression fracture of her third thoracic vertebra, and developed a severe thoracic kyphosis. Her medical history was significant for hypertension, well controlled with hydrochlorothiazide and a no. 2 clonidine patch, a symptomatic hiatal hernia treated with cimetidine, 300 mg, at bedtime, and bilateral asymptomatic carotid bruits with normal oculoplethysmography. Physical examina- tion showed a marked flexion deformity of the thoracic spine, extension of the cervical spine, and severely limited range of motion of the neck. Findings in the remainder of the physical examination were unremarkable. The patient was scheduled to undergo a staged repair of her kyphosis. Results of routine laboratory studies were within normal limits. Pulmonary function testing was consistent with a moderate restrictive defect. The electrocardiogram showed inverted T waves inferolaterally and increased right ventricular voltage. Car- diopulmonary exercise testing showed significant pulmonary impairment during exercise with normal cardiac perfor- mance. Magnetic resonance imaging showed a 90° kyphosis at the level of the third and fourth thoracic vertebrae (Fig 1). Myelography showed no compression of the spinal cord. The anterior release and fusion were to be done through a thoracotomy incision and required placement of a DLT to facilitate exposure of the thoracic spine. Because of the patient’s pulmonary disease, hiatal hernia, tracheal, cervical, and thoracic deformities, it was decided that an awake intubation was indicated. The patient received no premedica- tion. Upon arrival in the operating room, a precordial stethoscope, electrocardiograph, automated blood pressure cuff, radial arterial catheter, and pulse oximeter were placed. The patient was sedated with 1.25 mg of droperidol and 5 pg of sufentanil. Baseline somatosensory evoked responses were obtained. Anesthesia of the airway was obtained with topical

A 64-year-old man had increasing back pain and decreasing sensation over the T&10 dermatomes. His medi- cal history was significant for severe degenerative disease of the cervical spine. Six months before admission, the patient underwent a posterior thoracic laminectomy and discectomy for right lower-extremity paresis with good results until the onset of the present symptoms. Physical examination showed decreased pinprick sensation over the T8-10 dermatomes on the right and T8 on the left, and slightly decreased strength and sustained clonus in the right lower extremity. Somatosen- sory-evoked responses showed no responses from the posterior tibia1 stimulation bilaterally, and reproducible responses from right median nerve stimulation that showed increased latency. Myelography showed an extradural defect at T7-9 and spinal stenosis at L2-4. The patient was scheduled for anterior discectomy at T8-9. Results of routine preoperative laboratory studies were within normal limits. The surgeons requested the placement of a DLT to facilitate exposure. Because of the patient’s cervical spine disease, it was elected to intubate him awake, which allowed neurologic assessment after intubation and positioning. He received no premedica- tion. On arrival in the operating room, a precordial stetho- scope, electrocardiograph, automatic blood pressure cuff, radial arterial catheter, and pulse oximeter were placed. The patient was sedated with 10 rg of sufentanil and 2.5 mg of

From the Walter Reed Army Medical Center, Wash- ington, DC.

Address reprint requests to Paul S. Patane. MD. Anesthesia and Operative Service, Walter Reed Army Medi- cal Center, Washington, DC 20307.

This is a US government work. There are no restric- tions on its use.

0888-6296/90/0402-0012S00.00/0

Journal of Cardiothoracic Anesthesia, Vol4. No 2 (April), 1990: pp 229-23 1 229

230 PATANE, SELL, AND MAHLA

Fig 1. Magnetic resonance imaging of patient’s thorax.

droperidol. Anesthesia of the airway was obtained as in case 1. A 3.5-mm fiberoptic bronchoscope was placed through the lumen of a no. 41 left-sided DLT and advanced, under fiberscopic guidance, orally to the cords. The trachea was visualized, and the tube was positioned by differential breath sounds and bronchoscopy. The patient tolerated the intuba- tion without complaint, hemodynamic response, or recall. The neurologic examination was unchanged after intubation and positioning. The operative and postoperative course was uneventful.

DISCUSSION

Awake intubation using nerve blocks, seda- tion, and bronchoscopy is an accepted technique for securing the airway in patients with anatomic airway abnormalities or neurological compro- mise. In the past, patients who were to undergo split-lung function testing were intubated en- dobronchially under local anesthesia.4 Awake endobronchial intubation for anesthesia and tho- racic surgery using topical anesthesia was de- scribed by Bjork et al’ in 1953. These uncomfort-

able procedures were eventually abandoned in favor of placement under general anesthesia. Awake endobronchial intubation has not been reported since the availability of the fiberoptic bronchoscope.

There are of course many ways to accom- plish an awake intubation. Bjork et al5 effected awake endobronchial intubation by using a mix- ture of topical tetracaine and cocaine. Topical anesthesia has also been safely obtained using lidocaine.6 It is common in this institution to perform glossopharyngeal, superior laryngeal, and transtracheal nerve blocks with lidocaine for awake intubations. A combination of topical anesthesia for the mouth and oropharynx fol- lowed by superior laryngeal and transtracheal nerve blocks may also be used. All of these techniques are acceptable as long as adequate airway anesthesia is achieved. A narcotic and droperidol were selected to produce comfort and

AWAKE FIBEROPTIC ENDOBRONCHIAL INTUBATION 231

amnesia, respectively. Midazolam, a short-acting benzodiazepine, may be preferable as an amnes- tic agent and anxiolytic in these patients, since it will allow a more rapid intraoperative wake-up than droperidol, should this be desired.

The bronchoscope should easily pass through the center of the endotracheal tube without resistance. Lubrication with a sterile water-soluble lubricant may be helpful. In the cases reported, the Mallinckrodt Bronchocath endobronchial tube was used. These range from 28F to 41 F and have internal diameters ranging from 4.5 to 7.4 mm. Therefore, a 3.5-mm pediat- ric bronchoscope can easily pass through all of these. There is a great variety of bronchoscopes and DLTs on the market, and their dimensions should be checked before the procedure to assure ease of manipulation of the bronchoscope through the tube. Care should be taken in placement and withdrawal of the scope through the tube, as

these instruments are expensive and fragile. In- ability to slide the endotracheal tube off the bronchoscope may be caused by kinking of the instrument. This is most likely to occur with a thin scope. Standard endotracheal tubes are short enough that a sufficient portion of the scope is free to allow manipulation. Insertion of the bronchoscope through the longer DLT leaves little of the bronchoscope distal to the end of the endobronchial tube. A solution to this is to cut the ends of the tube to accommodate the rela- tively short bronchoscope.3 Any resistance in placement, manipulation, or withdrawal should alert the operator to the possibility that the bronchoscope is in danger of being damaged.’

In summary, the bronchoscope has revolu- tionized the approach to the difficult airway and greatly facilitates the placement of endobron- chial tubes in the asleep and the awake patient.

REFERENCES

1. Raj PP, Forestner J, Watson TD, et al: Techniques for fiberoptic laryngoscopy in anesthesia. Anesth Analg 53:708-714, 1974

2. Shinnick JP, Freedman P: Bronchofiberscopic placement of a double-lumen endotracheal tube. Crit Care Med 10:544-545, 1982

3. Shulman MS, Brodsky JB, Levesque PR: Fiberop- tic bronchoscopy for tracheal and endobronchial intubation with a double-lumen tube. Can J Anaesth 34:172-173, 1987

4. Gaensler EA: Bronchospirometry. J. Lab Clin Med 39~917-934, 1952

5. Bjork VO, Carlens E, Friberg 0: Endobronchial anesthesia. Anesthesiology 14:60-72, 1953

6. Sutherland AD, Williams RT: Cardiovascular re- sponses and lidocaine absorption in fiberoptic-assisted awake intubation. Anesth Analg 65:389-391, 1986

7. Siegel M, Coleprate P: Complication of fiberoptic bronchoscope. Anesthesiology 61:214-215, 1984