Medical Conditions with Airway Implications
D. John Doyle MD PhD FRCPC
Department of Anaesthesia
The Toronto Hospital, Toronto, Canada
Dr. D. John Doyle
Department of Anaesthesia
The Toronto Hospital
200 Elizabeth Street, Toronto, M5G-2C4
Canada
Telephone: 416-340-3242
Fax: 416-340-3698
Voice Pager: 416-375-0565
Table of Contents
Introduction
A number of medical conditions can present special
challenges to the anesthesiologist. This chapter reviews,
in synopsis format, some of the more common conditions
likely to affect airway management. I have tried to be
brief and to the point; however, for those interested,
numerous references are included.
Diabetes and the Airway
The link between diabetes mellitus and difficult
laryngoscopy has only been described in recent years. About
one third of long term type diabetics (juvenile onset) will
present with laryngoscopic difficulties. This is due at
least in part to diabetic "stiff joint syndrome"
characterized by short stature, joint rigidity, and tight,
waxy skin. The fourth and fifth proximal pharyngeal joints
are most commonly involved. Patients with diabetic stiff
joint syndrome have difficulty in approximating their palms
and cannot bend their fingers backward ("prayer sign").
When the cervical spine is involved, limited atlanto-
occipital joint motion may make laryngoscopy and intubation
quite difficult. Glycosylation of tissue proteins from
chronic hyperglycemia result in abnormal cross-linking of
collagen is believed to be responsible . Joint involvement
in diabetics is sometimes evaluated using a "palm test"
which determines how much of a patient's palm can be made
to make contact with a flat surface. Reissel et al.
studied laryngoscopic conditions in 62 diabetic patients
given a fentanyl/ thiopental/ vecuronium induction for
renal transplantation or vitrectomy surgery. Joint
stiffness, as judged by the "palm test" was shown to
correlate with difficulty in laryngoscopy.
Nichol and Zuck point out that "almost all of the
extension of the head on the neck that is helpful to the
laryngoscopist takes place at the atlanto-occipital joint".
In some cases of patients presenting with an "anterior
larynx" (which Nichol and Zuck view as a misnomer) head
extension is limited by abutment of the occiput against the
posterior tubercle of the atlas, with the result that the
cervical spine bows forward at laryngoscopy pushing the
larynx anteriorally. The same effect may occur in stiff
joint syndrome patients, not because of abutment of the
atlas against the occiput, but because of cervical spine
joint immobility.
Obstructive Sleep Apnea
Obstructive sleep apnea (OSA) consists of absent nasal and
oral airflow during sleep despite continuing respiratory
effort. This is generally due to backward tongue movement
and pharyngeal wall collapse (glossoptosis) secondary to
interference with the normal coordinated contraction of
pharyngeal and hypopharyngeal muscles. Enlargement of the
tongue, tonsils and/or adenoids is often contributory. OSA
is diagnosed by finding at least 30 episodes of apnea (of
duration at least 10 seconds) in a 7 hour study period.
Many, but not all, patients are obese. From an anaesthetic
viewpoint, OSA patients are particularly at risk for airway
obstruction during the induction and recovery phases of
anaesthesia. Management options range from heightened
clinical monitoring to use of artificial airway devices
(e.g. nasopharyngeal airway, Grudel airway), to carrying
out induction and recovery in a sitting or semi-sitting
position to minimize pharyngeal wall collapse.
Obesity
Patients 20% over their ideal weight are obese. When they
are 100% over this weight they are said to be "morbidly
obese". The obese patient has a reduced functional residual
capacity (FRC) with reduced pulmonary oxygen stores,
leading to rapid desaturation when apnea occurs. Obese
patients with a short thick neck, a large tongue and/or
redundant folds of oropharyngeal tissue may be difficult to
intubate and are at increased risk to develop airway
obstruction. Positive pressure ventilation may be more
difficult in these patients because of decreased chest wall
compliance (restrictive lung defect). The increased work of
breathing associated with obesity leads patients to take
smaller tidal volumes and breath at an increased
respiratory rate, leading to atelectasis,
ventilation/perfusion mismatching, and increased degrees of
airway closure. Should a surgical airway become necessary,
the situation is made much more difficult as the surgeon
attempts to identify the trachea deep in a mound of adipose
tissue. Very obese patients are at increased risk of
regurgitation/aspiration both because of increased
intraabdominal pressure and the high incidence of patients
having gastric fluid volumes greater than25 ml and gastric fluid
pH less than 2.5.
Anaesthetic Considerations in the Patient with Rheumatoid
Arthritis
Rheumatoid arthritis (RA) is a multisystem autoimmune
disease with many anesthetic implications. Patients with
RA may challenge the anesthesiologist at the time of
tracheal intubation because cervical spine instability. In
addition, temperomandibular joint (TMJ) or arytenoid joint
immobility may limit safe access to the airway. The
preoperative anesthetic assessment must focus on possible
airway difficulties. Patients must be questioned and
examined to ellicit evidence of neck pain, limitation of
cervical spine movement, nerve root impingement or spinal
cord compression. Lateral C-spine flexion-extension X-rays
are indicated in patients with cervical spine
symptamotology to assess the possibility of cervical spine
subluxation. The need for these X-rays in completely
asymptomatic patients remains controversial; however, one
should keep in mind case reports of neurological damage
following direct laryngoscopy and intubation in
asymptomatic patients. Patients with cervical spine
instability should generally be intubated and postioned
awake before surgery to avoid neurological injury. The
TMJs must be examined to ensure that mouth opening and
anterior subluxation of the mandible will permit direct
laryngoscopy. Patients demonstrating stridor or hoarseness
require awake direct or indirect laryngoscopy to assess the
possibility of arytenoid involvement and determine the size
of the glottic opening. Finally, the larynx may be
displaced from its usual location by erosion and
generalized collapse of the cervical vertibrae.
Zenker's Diverticulum
Zenker's diverticulum is an esophageal outpouching for
which patients sometimes seek a surgical repair. Because
food and other material may settle in the diverticulum,
there is a concern that any pouch material may find itself
into the airway with the induction of anaesthesia. Some
patients can manually empty the pouch themselves; others
may benefit from suction catheter placement in the pouch
prior to induction (easier said than done). One key thing
to remember, however, is this: application of cricoid
pressure (such as is done in a rapid sequence induction)
may actually dislodge any pouch contents into the
oropharynx.
Acromegaly
The acromegalic patient suffers from an excess of growth
hormone, usually from a pituitary adenoma. If this
condition occurs prior to closure of the epiphipeal growth
plates, giantism may occur. Once the growth plates have
fused in adolescence, the patient may take on acromegalic
features. From the viewpoint of airway management in the
acromegalic patient, three concerns exist: (1) the tongue
may be enlarged, (2) redundant folds of tissue may be
present in the oropharynx and (3) laryngeal stenosis occurs
more frequently than in the general population. These
factors may make laryngoscopy and intubation somewhat more
difficult and increase the likelihood of airway obstruction
during anaesthetic induction and recovery. Should true
giantism be encountered clinically (often for resection of
a pituitary adenoma), the following potential problems
should also be considered:
- possible need for an extra-long OR table
- possible need for an extra large laryngoscope
- ETTs may need to be cut longer then usual
- an extra large face mask may be necessary
Pregnancy
Pregnancy carries with it the following airway
considerations:
- Failed intubation (1:300-1:500 parturients) occurs
approximately five times more frequent than in the
general population. External assessment of the
parturient’s airway does not reliably predict
difficult intubation.
- Patient is generally regarded as a "full stomach"
after 16-20 weeks gestational age, with concern of
aspiration.
- Airway edema may be present, especially if the patient
is preeclamptic, so that a smaller than usual ETT may
be required.
- One-third to one-half of pregnant women in the supine
position develop airway closure during normal tidal
ventilation thus predisposing them to hypoxemia .
Increased oxygen consumption (20% higher at term than
in the nonpregnant state) associated with pregnancy
also increases the likelyhood that a parturient will
become hypoxic during induction of anesthesia.
- Big breasts may interfere with intubation.
Anaphylaxis
During anaphylactic (or anaphylactoid) reactions, massive
release of histamine and other noxious substances from mast
cells and basophils produce "leaky capillaries" which
result in interstitial fluid buildup (edema). When edema of
any portion of the airway results, respiratory obstruction
can occur. Airway-related clinical manifestations may
include dyspnea, stridor and facial edema. Erythema,
urticaria, bronchospasm and hypotension may also be
present. While many older textbooks advocate establishing a
surgical airway, early intubation is now the usual
recommendation if the airway appears to be at risk. Another
airway-related problem which may occur in anaphylaxis is
bronchospasm, sometimes with sufficient severity that air
entry is so poor that wheezing is not present and
ventilation may be next to impossible. As always, the
primary drug treatment in life-threatening anaphylaxis is
epinephrine (2-4 mcg/kg), either IV, SQ, or IM and repeated
at 5 - 10 minute intervals based on the patient's clinical
response.
Mediastinal Masses
Airway problems posed by mediastinal masses provide some of
the greatest challenges faced by clinical
anesthesiologists. Anesthesia is needed primarily for
diagnostic biopsies and staging of neoplasms but also
occasionally for relief of acute airway obstruction. The
choice of anesthesia is guided by the etiology and location
of the mass (extent and effect on adjoining(SP) airway or
cardiovascular structures). All patients require a
meticulous preoperative assessment that includes careful
history and physical exam aimed at delineating symptoms or
signs that may indicate compression of major airways, the
great vessels or the heart itself. For emergency relief of
airway compromise, one may have to precede with rigid
bronchoscopy as a means of relieving the obstruction and
determining the extent of airway compression. In elective
or semi-elective circumstances preoperative laboratory
investigations should include ECG, CXR, contrast CT scan of
the thorax and, if indicated by the patient's symptoms or
signs, an echocardiogram and/or pulmonary flow volume loops
with the patient sitting and supine (where available).
Great clinical judgement and experience must be exercised
by the anesthetist and surgeon in choosing a suitable
anesthetic plan. In general, short acting agents should be
used so that the patient returns to a "fully awake" state
immediately postoperavely. In instances where the mass is
small and does not compress ajoining structures one may
procede with an intravenous induction and institute
positive pressure ventilation. On the other hand, one must
be cognizant (SP) that airway or vascular compression may
worsen during general anesthesia. Thus a prudent approach
may include topical anesthesia of the airway followed by
awake fibreoptic
intubation of the trachea or inhalational induction
and spontaneous ventilation supplemented by manual
assistance. Seriously ill patients may requre diagnostic
biopsy or airway intrumentation with local anesthesia
alone as the risks of general anesthesia may outweigh
any possible benefits. In any event, a surgeon experienced
with rigid bronchoscopy must be present at induction
if the potential for airway compression is substantial.
If the airway is "lost" under anesthesia, placing the
patient in the lateral decubitus or prone position may
relieve the obstruction, however, rapid intubation of the
airway with a rigid bronchoscope is usually most effective.
Significant obstruction of the superior vena cava by tumor
(SVC syndrome) is indicated by cyanosis, engorged veins
and\or edema of the upper body. Patients with SVC syndrome
are especially prone to airway obstruction, hypotension and
massive hemorrhage. Ideally: patients should be kept in a
semi-upright position to reduce airway edema; diagnostic
tissue should be obtained under local anesthesia; packed
red cells should be available in the operating room; large
bore intravenous access should be obtained in the lower
extremities and; arterial catheter should be inserted
preoperatively.
MEDIASTINAL MASSES: Practical Points
- Signs and symptoms indicating airway compromise
include: stridor, orthopnea, dyspnea, cyanosis, cough,
decreased breath sounds and wheezes.
- Signs and symptoms indicating critical cardiovascular
compression include: fatigue, neck/facial edema,
faintness, JVD, headache, papilleadema, dyspnea,
pulsus paradoxus, orthopnea, postural changes in BP
and pallor.
- If there is SVC obstruction, don't put an IV in the
arms; the main source of venous return is the IVC, so
the main IV will have to go in a leg.
- With an anterior mediastinal mass, the mass compresses
the mediastinal structures to varying degrees.
Compression is maximal with the patient lying supine,
and would be expected to be less with the patient
lying prone or on his or her side. If the patient
seems to be getting into trouble when positioned
supine, consider placing the patient on his or her
side, or even prone.
- With SVC obstruction the face may become edematous and
venous engorgement is present. The edema is a concern
from the viewpoint of airway management - special
concern must be given to these patients when they are
extubated. The venous engorgement is potentially a
problem when nasal intubation is being considered
(popular for
fiberoptic intubation); the engorgement of
nasopharyngeal veins may lead to troublesome epistaxis.
- Echocardiography serves to evaluate myocardial
contractility and for assessment of
tumor encasement of the heart and great vessels.
- Patient history information (especially symptoms when
supine) often tells most of the story. That, together
with a CT scan of the thorax and a chest x-ray provide
the most important information. Differences between
sitting and supine flow volume loops can help test for
intrathoracic or extrathoracic obstruction. (However,
most pulmonary function labs are not set up to do
flow-volume loops in the supine position.) Fiberoptic
bronchoscopy also evaluates dynamic AW obstruction.
Finally, never forget that patients asymptomatic while
awake may obstruct their airway during anaesthesia.
- In emergency situations where there is no time for a
more complete assessment, increased emphasis must be
placed on the clinical findings, especially signs and
symptoms in the supine position. Options to consider
in this case: (a) awake FOB for intubation, checking
for dynamic airway collapse, and (b) maintenance of
spontaneous breathing throughout (muscle relaxants may
lead to airway loss).
- Where appropriate, preoperative radiation or
chemotherapy should be considered to shrink sensitive
tumors and alleviate symptoms.
Epiglottitis
Epiglottitis is the most dreaded of airway infections,
especially in children. Victims are usually children age 2
to 6, often infected with H. flu. These children may
appear to be systemically ill ("toxic") perhaps with a
fever and/or perhaps sitting up in a "tripod" position and
drooling from difficulty with swallowing. Examining the
child's airway may exacerbate the problem (by increasing
airway edema) so tongue depressors and laryngoscopy are not
options in the inital management of the child. Anything
that might bring the child to cry (for example, needles)
should generally be avoided. Consequently (and for other
reasons), the usual approach to management involves a
careful inhalational induction with the child sitting in
the anesthetist's lap and intubation of the child while he
or she is breathing spontaneously under deep halothane
anesthesia. If at laryngoscopy the orifice through the
epiglottis can't be identified, one trick is to have
someone compress the child's chest, thus generating a small
bubble in the epiglottis that the anesthetist can aim for.
In the past patients were managed by emergency
tracheostomy, however contemporary management of children
includes short term nasal intubation and intravenous
antibiotic therapy. There is considerable disagreement
concerning airway management in the adult however there
seems to be a growing concensus that the majority of adults
are adequately treated in an intensive care unit with
inhaled mist, antibiotics and corticosteroids and that
tracheal intubation is necessary only if symptoms of
respiratory distress develop.
Epiglottitis can occur in adults too (George Washington is
said to have died of it) but the situation is less dreadful
here because the adult airway is larger. Most people would
use awake
fiberoptic laryngoscopy to secure the airway in
this situation. There is growing experience with
conservative management of adult epiglottitis (admission to
an ICU for intravenous antibiotic therapy and with
avoidance of intubation).
The Airway in HIV-Infected Patients
With increasing frequency, clinicians are becoming aware of
airway-related problems in HIV-infected individuals. For
example, Kaposi's sarcoma in AIDS patients has been
reported to result in airway obstruction. Similarly,
opportunistic infections can also result in airway
obstruction. A recent review by Judson and Sahn
provides additional information for the interested reader.
Ludwig's Angina
Ludwig's angina is a multispace infection of the floor of
the mouth. The infection starts with infected mandibular
molars and spreads to sublingual, submental, buccal and
submandibular spaces. The tongue becomes elevated and
displaced posteriorally, which may lead to loss of the
airway, especially when the patient is placed in the supine
position. An additional concern is the potential for
abscess rupture into the hypopharynx (with possible lung
soiling) either spontaneously or with attempts at
laryngoscopy and intubation. Airway management options will
depend on clinical severity, surgical preferences, and
other factors (e.g. CT findings), but elective tracheostomy
prior to incision and drainage remains the classical
treatment modality (although many experts advocate
fiberoptic intubation
if at all possible.
Retropharyngeal Abscess
Retropharyngeal abscess formation may occur from bacterial
infection of the retropharyngeal space secondary to a
tonsillar or dental infections . Untreated, the posterior
pharyngeal wall may advance anteriorally into the
oropharynx, resulting in a dyspnea and airway obstruction.
Other clinical findings may include difficulty in
swallowing, trismus and a fluctuant posterior pharyngeal
mass. An abscess cavity may be evident on lateral neck x-
rays with anterior displacement of the esophagus and upper
pharynx. Airway management may be complicated by trismus or
airway obstruction. Because abscess rupture can lead to
soiling of the trachea, contact with the posterior
pharyngeal wall during laryngoscopy and intubation should
be minimized. Incision and drainage is the mainstay of
treatment. Tracheostomy is often, but not always required.
Tables
Table 1 - Some Nonneoplastic Noninfectious Medical Conditions
with Airway Implications
- Rheumatoid Arthritis
- Diabetes Mellitus
- Pregnancy
- Acromegaly/Giantism
- Obstructive Sleep Apnea
- Obesity
- Anaphylaxis
Table 2 - Some Infections Conditions with Airway Implications
- Ludwig's Angina
- Retropharyngeal Abscess
- Epiglottitis
- Tracheolaryngobronchitis
- Submandibular Abscess
- Pneumonia
Table 3 - Some Neoplastic Conditions with Airway Implications
- Laryngeal Papillamatosis
- Carcinoma of the Oral Cavity
- Bronchogenic Carcinoma
- Anterior Mediastinal Mass
- Epiglottic Cysts
- Thyroid Goitre
Table 4 - Anaesthetic Considerations in the Patient with Rheumatoid
Arthritis
- Airway-Related Considerations
- Possible cervical spine subluxation
- Possible TMJ involvement
- Possible involvement of arytenoids
- Possible laryngeal twisting
- Possible systemic complications of RA
- Cardiac involvement
- Special care is needed in patient positioning
- Patients may be on ASA or other platelet inhibiting drugs
- Patients may be on systemic corticosteroids
Table 5 - PATHOLOGY OF MEDIASTINAL MASSES
- Anterior Mediastinum
- thymomas (remember association with myasthenia gravis
[50% cases])
- thyroid tumors extending below sternum
- lymphoma
- teratoma
- Middle Mediastinum
- lymphoma
- aneurysms
- esophagus (achalasia, diverticula)
- cysts (bronchogenic, pericardial)
- Posterior Mediastinum
- tumors of neurogenic origin
- Children
- bronchial cysts, teratomas, lymphomas (anterior and
middle), neurogenic tumors (posterior)
Table 6 - Mediastinal Masses: Central questions to decide based on
patient evaluation
- Is there SVC obstruction?
- Is there tracheal compression?
- Is the PA involved?
- Is the heart involved?
Table 7 - Mediastinal Masses: Useful information to assess anterior
mediastinal masses:
- Clinical presentation (signs, symptoms and clinical findings;
most important)
- Chest x-ray
- CT scan of chest
- Flow-volume loops (sitting and supine)
REFERENCES AND BIBLIOGRAPHY
Adair JC, Ring WH: Management of epiglottitis in children.
Anesthesia & Analgesia 54:622-625, 1975
Amaha K, Okutsu Y, Nakamuru Y: Major airway obstruction by
mediastinal tumour. A case report. Br J Anaesth 45:1082-
4, 1973
Andreassen UK, Husum B, Tos M, Leth N: Acute epiglottitis
in adults. A management protocol based on a 17-year
material. Acta Anaesthesiologica Scandinavica 28:155-157,
1984
Archer GW Jr, Marx GF: Arterial oxygen tension during
apnoea in parturient women. Br J Anaesth 46:358-60, 1974
Arndal H, Andreassen UK: Acute epiglottis in children and
adults. Nasotracheal intubation, tracheostomy or careful
observation? Current status in Scandinavia. Journal of
Laryngology & Otology 102:1012-1016, 1988
Baines, D.B., Wark, H. and Overton, J.H. Acute epiglottitis
in children. Anaesthesia & Intensive Care 13:25-28, 1985.
Battaglia, J.D. and Lockhart, C.H. Management of acute
epiglottitis by nasotracheal intubation. American Journal
of Diseases of Children 129:334-336, 1975
Baughn RW, BauerS, Wise L: Volume and pH of gastric juice
in obese patients. Anesthesiology 43:686-9,
Benjamin B, O'Reilly B: Acute epiglottitis in infants and
children. Annals of Otology, Rhinology & Laryngology
85:565-572, 1976
Berlinger NT, Freeman TJ: Acute airway obstruction due to
necrotizing tracheobronchial aspergillosis in
immunocompromized patients: a new clinical entity. Ann
Otol Rhinol Laryngol 98:718, 1989
Bevan DR, Holdcroft A, Loh L, MacGregor WG, O’Sullivan JC:
Closing volume and pregnancy. Br Med J 1:13-5, 1974
Blanc VF, Weber ML, Leduc C, Laberge R, Desjardins R,
Perreault,G: Acute epiglottitis in children: management of
27 consecutive cases with nasotracheal intubation, with
special emphasis on anaesthetic considerations. Canadian
Anaesthetists Society Journal 24:1-11, 1977
Bray GA, Gray DS: Obesity. Part 1. Pathogenesis. West J
Med 149:429-41, 1988
Bray RJ, Fernandes FJ: Mediastinal tumour causing airway
obstruction in anaesthetized children. Anaesthesia 37:571-
5, 1982
Brazeau-Lamontagne L, Charlin B, Levesque RY, Lussier A:
Cricoarytenoiditis: CT assessment in rheumatoid arthritis.
Radiology 158:463-466, 1986
Breivik H, Klaastad O: Acute epiglottitis in children.
Review of 27 patients. British Journal of Anaesthesia
50:505-510, 1978
Buckingham B, Uitto J, Sandborg C, Keens T, Kaufman F,
Landing B: Scleroderma-like syndrome and the non-enzymatic
glycosylation of collagen in children with poorly
controlled insulin dependent diabetes (IDDM). Pediatric
Research 5:A626, 1981
Buckley FP, Robinson NB, Simonowitz DA, Dellinger EP:
Anaesthesia in the morbidly obese. A comparison of
anaesthetic and analgesic regimes for upper abdominal
surgery. Anaesthesia 38:840-51, 1983
Butt W, Shann F, Walker C, Williams J, Duncan A, Phelan P:
Acute epiglottitis: a different approach to management.
Critical Care Medicine 16:43-47, 1988
Carenfelt C: Etiology of acute infectious epiglottitis in
adults: septic vs. local infection. Scandinavian Journal of
Infectious Diseases 21:53-57, 1989
Chapple M, Jung RT, Francis J, Webster J, Kohner EM, Bloom
SR: Joint contractures and diabetic retinopathy.
Postgraduate Medical Journal 59: 291-4, 1983
Cheek TG, Gutsche BB: Maternal physiologic alterations
durng pregnancy in Anesthesia for obstetrics 2nd Ed.
Shnider SM and Levinson G (Eds) Williams and Wilkins,
Baltimore 1987 pp 10 ??
Claesson B, Trollfors B, Ekstr:om-Jodal B, Jeppsson PH,
Lagerg:ard T, Nyl:en O, Rign:er P: Incidence and prognosis
of acute epiglottitis in children in a Swedish region.
Pediatric Infectious Disease 3:534-538, 1984
Crosby E, Reid D: Acute epiglottitis in the adult: is
intubation mandatory? Canadian Journal of Anaesthesia
38:914-918, 1991
Davies JM, Weeks S, Crone LA, Pavlin E: Doffoci;t
omtibatopm om tje [artiroemt/ Can J Anaesth 36:668-74,
1989
Deeb ZE, Yenson AC, DeFries HO: Acute epiglottitis in the
adult. Laryngoscope 95:289-291, 1985
De Heyn G, Mullier JP, De Smet JM: Etiology and therapy of
Ludwig's angina. Acta Oto-Rhino-Laryngologica Belgica.
33(2):235-41, 1979
DiTirro FR, Silver MH, Hengerer AS: Acute epiglottitis:
evolution of management in the community hospital.
International Journal of Pediatric Otorhinolaryngology
7:145-152, 1984
Eleborg L, Norberg AA: Are diabetic patients difficult to
intubate? Acta Anaesthesiologica Scandinavica 32: 508,
1988
Farebrother MJB: Respiratory function and
cardiorespiratory response to exercise in obesity. British
Journal of Diseasese of the Chest 73: 211-39, 1979
Fontanarosa PB, Polsky SS, Goldman GE: Adult epiglottitis.
Journal of Emergency Medicine 7:223-231, 1989
Fritsch DE, Klein DG: Ludwig's angina. Heart & Lung
21(1):39-46, 1992
Funk D, Raymon F: Rheumatoid arthritis of the
cricoarytenoid joints: an airway hazard. Anesthesia &
Analgesia 54:742-745, 1975
Geterud A, Bake B, Berthelsen B, Bjelle A, Ejnell H:
Laryngeal involvement in rheumatoid arthritis. Acta Oto-
Laryngologica 111:990-998, 1991
Geterud A, Ejnell H, M:ansson I, Sandberg N, Bake B, Bjelle
A: Severe airway obstruction caused by laryngeal
rheumatoid arthritis. Journal of Rheumatology 13:948-951,
1986.
Goldhill DR, Dalgleish JG, Lake RH: Respiratory problems
and acromegaly. An acromegalic with hypersomnia, acute
upper airway obstruction and pulmonary oedema. Anaesthesia
37:1200-1203, 1982
Gonzalez C, Reilly JS, Kenna MA, Thompson AE: Duration of
intubation in children with acute epiglottitis.
Otolaryngology - Head & Neck Surgery 95:477-481, 1986
Greenberg JE, Fischl MA, Berger JR: Upper airway
obstruction secondary to acquired immunodeficiency
syndrome-related Kaposi’s sarcoma. Chest 88:638, 1985
Greenberg LW, Schisgall R: Acute epiglottitis in a
community hospital. American Family Physician 19:123-127,
1979
Grfic A, Rosenbloom AL, Weber FT, Giordano B, Malone JI:
Joint contracture in childhood diabetes. New England
Journal of Medicine 292:372, 1975
Hassan SZ, Matz GJ, Lawrence AM, Collins PA: Laryngeal
stenosis in acromegaly: a possible cause of airway
difficulties associated with anesthesia. Anesthesia &
Analgesia 55:57-60, 1976
Heller PJ, Scheider EP, Marx GF: Pharyngolaryngeal edema
as a presenting symptom in preeclampsia. Obstet Gynecol
62:523-4, 1983
Hogan K, Rusy D, Springman SR: Difficult laryngoscopy and
diabetes mellitus. Anesthesia and Analgesia 67:1162-5,
1988
Holland CS: The management of Ludwig's angina. British
Journal of Oral Surgery. 13(2):153-59, 1975
Imoto EM, Stein RM, Shellito JE, Curtis JL: Central airway
obstruction due to cytomegalovirus-induced necrotizing
tracheitis in a patient with AIDS. Am Rev Respir Dis
142:884, 1990
Judson MA, Sahn SA: Endobronchial lesions in HIV-infected
individuals. Chest 105:1314, 1992
Khilanani U, Khatib R: Acute epiglottitis in adults.
American Journal of the Medical Sciences 287:65-70, 1984
Lee JJ, Larson RM, Buckley JJ, Roberts AB: Airway
maintenance in the morbidly obese. Anesthesiology Review
7:33-6, 1980
Leicht MJ, Harrington TM, Davis DE: Cricoarytenoid
arthritis: a cause of laryngeal obstruction. Annals of
Emergency Medicine 16:885-888, 1987
Luce JM: Respiratory complications of obesity. Chest
78:626-31, 1980
Mackenzie AI: Laryngeal oedema complicating obstretric
anaesthesia. Anaesthesia 1978; 33: 271
Mackie AM, Watson CB: Anaesthesia and mediastinal masses.
Anaesthesia 39:899-903, 1984
MayoSmith MF, Hirsch PJ, Wodzinski SF, Schiffman FJ: Acute
epiglottitis in adults. An eight-year experience in the
state of Rhode Island. New England Journal of Medicine
314:1133-1139, 1986
McGeehan DF, Crinnion JN, Strachan DR: Life-threatening
stridor presenting in a patient with rheumatoid involvement
of the larynx. Archives of Emergency Medicine 6:274-276,
1989
McNelis FL: Medical and legal management of adult acute
epiglottitis. Laryngoscope 95:125-127, 1985
Mezon BJ, West P, MaClean JP, Kryger MH: Sleep apnea in
acromegaly. American Journal of Medicine 69:615-618, 1980
Neuman GG, Weingarten AE, Abramowitz RM, et al: The
anesthetic management of the patient with an anterior
mediastinal mass Anesthesiology 60:144-7, 1984
Norton ML, Brown ACD: Evaluating the patient with a
difficult airway for anesthesia. Otolaryngol Clin North Am
23: 771-85, 1990
Patterson HC, Kelly JH, Strome M: Ludwig's angina: an
update. Laryngoscope 92(4):370-8, 1982
Piro AJ, Weiss DR, Hellman S: Mediastinal Hodgkin’s
disease: a possible danger for intubation anesthesia. Int
J Radiat Oncol Biol Phys 1:415-9, 1976
Prakash UBS, Abel MD, Hubmay RD: Mediastinal mass and
tracheal obstruction during general anesthesia. Mayo Clin
Proc 63:1004-7, 1988
Redlund-Johnell I: Upper airway obstruction in patients
with rheumatoid arthritis and temporomandibular joint
destruction. Scandinavian Journal of Rheumatology 17:273-
279, 1988.
Reissell E, Orko R, Maunuksela EL, Lindgren L:
Predictability of difficult laryngoscopy in patients with
long-term diabetes mellitus. Anaesthesia 45:1024-1027,
1990
Rivron RP, Murray JA: Adult epiglottitis: is there a
consensus on diagnosis and treatment? Clinical
Otolaryngology 16:338-344, 1991
Rocke DA, Murray WB, Rout CC, Gouws E: Relative risk
analysis of factors associated with difficult intubation in
obstetric anesthesia. Anesthesiology 77: 67-73, 1992
Russell IF, Chambers IF: Closing volume in normal
pregnancy. Br J Anaesth 53:1043-7, 1981
Salzarulo HH, Taylor LA: Diabetic `still joint syndrome'
as a cause of difficult endotracheal intubation.
Anesthesiology 64:366-8, 1986
Schneller S: Medical considerations and perioperative care
for rheumatoid surgery. Hand Clinics 5:115-126, 1989
Schwartz HC, Bauer RA, Davis NJ, Guralnick WC: Ludwig's
angina: use of fiberoptic
laryngoscopy to avoid tracheostomy. Journal of Oral
Surgery 32(8):608-11, 1974
Seibold JR: Digital sclerosis in children with insulin-
dependent diabetes mellitus. Arthritis and Rheumatism
25:1357-61, 1982
Sendi K, Crysdale WS: Acute epiglottitis: decade of
change--a 10-year experience with 242 children. Journal of
Otolaryngology 16:196-202, 1987
Sethi DS, Stanley RE: Deep neck abscesses--changing
trends. Journal of Laryngology & Otology 108(2):138-43,
1994
Singelyn FJ, Scholtes JL: Airway obstruction in
acromegaly: a method of prevention. Anaesthesia & Intensive
Care 16:491-492, 1988
Stair TO, Hirsch BE: Adult supraglottitis. American
Journal of Emergency Medicine 3:512-518, 1985
Stanley RE, Liang TS: Acute epiglottitis in adults (the
Singapore experience). Journal of Laryngology & Otology
102:1017-1021, 1988
Trollfors B, Nylen O, Strangert K: Acute epiglottitis in
children and adults in Sweden 1981-3. Archives of Disease
In Childhood 65:491-494, 1990
Tveter:as, K, Kristensen S: Acute epiglottitis in adults:
bacteriology and therapeutic principles. Clinical
Otolaryngology 12:337-343, 1987
Vassallo CL: Rheumatoid arthritis of the cricoarytenoid
joints; cause of upper airway obstruction. Archives of
Internal Medicine 117:273-275, 1966
Vernon DD, Sarnaik AP: Acute epiglottitis in children: a
conservative approach to diagnosis and management.
Critical Care Medicine 14:23-25, 1986
Widlund G: Cardio-pulmonal function during pregnancy: A
clinical-experimental study with particular respect to
ventilation and oxygen consumption among normal cases in
rest and after word tests. Acta Obstet Gynaecol Scand
25:1-??, 1945
Wurtele P: Nasotracheal intubation--a modality in the
management of acute epiglottitis in adults. Journal of
Otolaryngology 13:118-122, 1984
Ziemer DC, Dunlap DB: Relief of sleep apnea in acromegaly
by bromocriptine. American Journal of the Medical Sciences
295:49-51, 1988