- Email: [email protected]
Spectrum of Advanced Upper Airway Obstruction due to Goiters
Spectrum of Advanced Upper Airway Obstruction due to Goiters* Stephen R. Karbowitz, M.D., F.C.C.P.; Leonard B. Edelman, M.D.; Sunil Nath, M.D.; Joe H. Dwek, M.D., F.C.C.P.; and Gumpeni Rammohan, M.D., F.C.C.P.
Five patients with advanced upper airway obstruction due to goiter were identified in our institution. All had symptoms of respiratory insufficiency to such a degree that surgery was clearly indicated. FUnctional characteristics of this
group were compared with prior series of goiter patients who had less severe respiratory symptoms. A peak inspiratory flow less than 1.5 Usee characterized this group who required surgery.
airway obstruction (UAO) caused by goiter U pper varies from asymptomatic patients with abnormal flow-volume curves, 1 to reports of acute respiratory failure. 2-5 It became apparent after study of our index patient (case 1) with chronic ventilatory failure due to a substernal goiter, that there was only anecdotal reporting of patients with advanced UAO due to goiter. Specific physiologic criteria characterizing those patients who required surgery for goiter is absent from the screening study of the flow-volume curve and goiter as reported by Jauregui et al. 1 Thus, after our index case, we prospectively screened all How-volume curves in our laboratory and all patients with respiratory insufficiency consultations for UAO due to goiter. We identified five patients with goiters severe enough to require surgical correction because of symptomatic airway compromise, and flow-volume curves typical of U AO according to the criteria of Rotman et al. 6 These patients were identified over a three-year period. All studies were performed with an automated mass flow meter. We believe the characteristics of this group offer a better insight into this subset of patients with severe UAO and goiter.
-
c.) Q)
CASE
1
A 63-year-old man was admitted for progressive dyspnea and ventilatory failure. He was a heavy smoker for 40 years. He had noted dilated veins on his chest for two years. On admission, he was in moderate respiratory distress. Respirations were 20/min, blood pressure, 170/100 mm Hg, pulse, 86 per minute, and he was afebrile. His thyroid was enlarged, nodular, and was estimated at 75 g. Examination of the chest revealed bilateral basilar rales. There was no definite stridor or wheezing. Heart sounds were normal. Laboratory studies were most remarkable for evidence of chronic hypercapnia (Table 1). This was initially assumed to be due to chronic obstructive lung disease. The chest roentgenogram revealed a superior mediastinal mass extending to the thoracic inlet and *From the Pulmonary Section, Department of Medicine, Booth Memorial Medical Center, Flushing, NY. Manuscript received April30; revision accepted July 6. Reprint requests: Dr: Karbowitz, Booth Memorial Hospital, 56-45 Main Street, Flushing, New York 11355
18
0 1 2
I
(I)
........
--
0
(I)
1
2
I
34
~
Q)
@
....J
w
1-
<[
0::
3':
0
....J
LL. CASE REPORTS
®
4 3 2 1
7 6 5 4 3 2 1
0
1 2 3 4 5
0
1
2
3
4
VOLUME (Liters) FIGURE 1. Flow-volume curve of patient 1 before (A) and after (B) removal of substernal thyroid. Advanced Upper Airway Obstruction due to Goitels (Karbowltz et a/)
Table !-Clinical and Physiologic Featun1s q{Goiters Causing Severe Upper Ainoay Obstruction* Patient
Clinical Presentation Ventilatory failure Stridor
1 2
Pathology Multinodular goiter Multinodular goiter Multinodular goiter
Enlarging goiter despite throxine Follicular Choking adenoma sensation stridor Multinodular Ventilatory failure goiter stridor Mean befOre surgery SD Mean befOre surgery SD Statistical significance by paired Student's
3
4
5
lA>cation Substernal Substernal Cervical
Cervical
Substernal
PaC02, mmHg
PEF Us
PIF Us
b 57 b 7.36 a44 a 7.40 b40 b 7.38 a 7.45 a 37 bNA bNA aNA aNA
4.4 6.2 2.3 4.5 5.5 5.8
1.7 1.7 4.3 3.7 3.5 1.3 1.9 1.2 2.3 3.1 1.2 3.8 3.2 4.2
bNA a30
bNA a 7.44
5.2 3.9
1.4 1.8
2.5 2.3
b59 a43
b 7.38 a 7.50
NA NA
NA NA NA
NA NA
4.35 1.44 5.10 1.08 NS
1.40
2.47
pH
b a t-test
.22 2.90 1.10 p<0.10
VE50 Us
VJ50
Us
VES0NJ50
1.5
2.1 0.6 2.4
1.2 1.0 1.6 1.5 6.3 1.8
1.5 1.7 1.7
1.4
NA NA
.95 3.33 .82 NS
NA 1.20 .42 2.43 .77 p<0.10
2.70 2.41 1.43 .33 NS
*Definition of abbreviations: PIF, peak inspiratory flow; PEF, peak expiratory flow; VE50, maximum expiratory flow at 50% of vital capacity; VJ50, maximum inspiratory flow at 50% of vital capacity; b, befOre surgery; a, after surgery; NS, not significant; NA, not available. deviating the trachea to the left. The initial flow-volume curve demonstrated evidence ofUAO (Fig IA). Thyroid scan with technetium 99m demonstrated an enlarged thyroid with mediastinal extension. During his hospital stay, he was initially treated with aminophylline and bronchodilator inhalation. During this therapy, his PaC02 remained above 55 mm Hg. It was decided that the goiter itself could be the cause of the chronic ventilatory failure. The patient underwent a total thyroidectomy with removal of a benign multinodular goiter of 175 g through a cervical incision. Postoperatively, the patient was fully relieved of dyspnea. The PaC02 one month postoperatively was 44 mm Hg. Repeat flow-volume curves one month postoperatively showed correction ofUAO (Fig 18). CASE
2
A 67-year-old woman was admitted for evaluation of progressive dyspnea on exertion. The patient was noted to have stridor after walking one block to the medical clinic. Physical examination demonstrated a small cervical goiter. Chest roentgenograms showed a widened mediastinum superiorly, without obvious change for the past three years. Roentgenographic interpretation was initially that of tortuous great vessels. Technetium scans confirmed a goiter in the neck extending through the thoracic inlet into the substernal area. The CT scans confirmed a marked narrowing of the trachea. Flowvolume curves revealed the pattern of UAO. After removal of her substernal goiter, all symptoms disappeared. CASE
3
This 45-year-old woman was admitted fur thyroidectomy fur a cervical goiter that was enlarging despite thyroxine therapy. The patient had choking sensations but no consistent dyspnea. A chest roentgenogram showed a mass at the thoracic inlet with a narrow tracheal lumen. The flow-volume curve confirmed variable extrathoracic UAO. After removal of the goiter, there were no further episodes of choking. CASE
4
A 78-year-old woman with cervical goiter that had been asymptomatic fur many years, was admitted with episodes of choking and stridor over a one-year period. On examination, a 5 X 6 em goiter was
palpated. Tracheal tomograms showed intrinsic compression. The Bow-volume curve confirmed UAO. After removal of the goiter, she was asymptomatic and comfOrtable. CASE
5
This 89-year-old man was admitted because of progressive dyspnea of several weeks' duration. He was a cigar smoker. The dyspnea was initially assumed to be due to chronic obstructive lung disease. However, stridor was heard upon examination, and dilated veins were obvious across both shoulders. A chest roentgenogram demonstrated a substernal mass with widening of the superior mediastinum. He could not perform How-volume curves. Despite his age, he was advised to have the goiter removed because this was the single factor limiting his ability to function. He refused, until he developed acute respiratory failure requiring tracheal intubation and mechanical ventilation. It was felt that the patient could not be extubated until the goiter was removed. After surgery, he was promptly extubated and breathed without difficulty. RESULTS
All five patients had clear clinical requirements for surgical correction of a goiter. Three had stridor, two had acute exacerbation of ventilatory failure, and one had a goiter enlarging despite suppressive therapy with thyroxine. Four were multinodular goiters, and one was a follicular adenoma (Table 1). The substernal goiters were removed by cervical incisions. There was no postoperative complication. The mean peak expiratory flow (PEF) was 4.4 liters per second (Us) before surgery, and did not significantly change afterward (Table 1). The mean peak inspiratory flow (PIF) was 1.40 Us before surgery and doubled afterward (p<0.10). Similarly, the mean maximum flow at 50 percent of vital capacity during inspiration (VI50) doubled (p<0.10). The two patients with hypercapnia corrected postoperatively. CHEST I 87 I 1 I JANUARY, 1985
19
Table 2-Compariaon of Pretreatment Flow8: Patients with Severe Goit1'0U8 Upper Ainoay Obstruction va Unaelected Goiter Population•
Flows
Present Study (n=4) Mean±SD
Reference Study' (n=ll) Mean±SD
p Value by Paired Student's t-test
PEF VE50 VI50
4.35± 1.44 2.47±0.95 1.20±0.42
4.46± 1.99 3.15± 1.57 2.96±0.96
NS NS
<.05
•Definition of abbreviations: PEF, peak expiratory flow; VE50, maximum expiratory Bow at 50% of vital capacity; VI50, maximum inspiratory flow at 50% of vital capacity; NS, not significant.
DISCUSSION Our study demonstrates that a mean PIF of 1.5 Us identifies a subset of patients with goiter and UAO who require urgent surgery. This is consistent with the results of other clinical and experimental studies. 1·7 •8 Jauregui et al' reported a mean VI50 of2.96 Us in a group of 11 patients treated for goiter. Of this group, nine were treated successfully medically and two required surgical correction. His report did not elaborate as to which patients required surgery. This corresponds to a VI50 more than double that of the four patients in our group who performed flow-volume curves (Table 2). This difference is significant (p<0.05) even in the small sample sizes of both groups. Miller and Hyate studied the flow-volume curves of seven healthy adult men while interposing a progressively narrowed orifice from 13 mm internal diameter (ID) to 4 mm ID. Flattening of the flow-volume curves became apparent at 6 mm ID. In changing the orifice from 6 mm ID to 4 mm ID, the PIF decreased from 3. 0 Us to 1.8 Us. This matches closely the difference between the VI50 of 2. 96 Us of Jauregui et al and our group of patients with severe symptoms of UAO and VI50 of 1.20 Us. This also is consistent with the report of Shim et al8 who found a maximum midinspiratory flow (MMIF) of less than 1.4 Us in patients with chronic UAO and significant limitation of function. One should note that PIF, VI50, and MMIF should all be fairly similar in patients with a flat inspiratory limb of the flow-volume curve. In our series of goiters, symptomatic UAO is correlated with the flow-volume curve. Shambaugh et al9 have shown that patients with goiters can remain asymptomatic for years and progress within days to lifethreatening airway obstruction. The weight of the excised gland did not correlate with the degree of obstruction. Therefore, patients should have frequent flow-volume curves to monitor for incipient UAO. A PIF or VI50 less than 1.5 Us is an indication for immediate thyroidectomy to avoid acute ventilatory failure. Careful review of the literature has failed to reveal a prior report of chronic hypercapnia solely due to 20
substernal goiter, such as we have demonstrated in case 1. Despite vigorous medical therapy with bronchodilators for possible intrinsic airway disease of the lung, there was no improvement in alveolar hypoventilation until after thyroidectomy. Numerous reports2.3.5.9.to have described acute respiratory failure from benign goiters. Voegel et al'0 reported benign goiter as a cause of postintubation airway obstruction. Canham and Sahn5 described a goiter suppressed by thyroxine causing rapidly progressive respiratory failure. These reports have emphasized acute respiratory failure in patients without previous flow-volume curves. In our series, case 1 demonstrates chronic ventilatory failure. This may represent an intermediate stage between an abnormal flow-volume curve and acute respiratory failure. This once again demonstrates the importance of serial flow-volume curves and frequent clinical evaluations. Other obstructing lesions of the upper airways, such as enlarged tonsils and adenoids, 11 have been documented as causing chronic UAO, pulmonary hypertension, and cor pulmonale in the pediatric population. In the adult, UAO and chronic ventilatory failure have been reported due to an aneurysm of the ascending aorta with normalization following surgery. 12 These lesions of the upper airway associated with chronic hypoventilation share two features. They are outside the tracheal lumen, either in the pharynx or in the mediastinum; and they are benign. These characteristics cause an extremely slow and indirect increase in the airway resistance as compared to intraluminal lesions. This may allow time for adaptive hypoventilation without acute dyspnea. Our index patient (case 1), clearly illustrates that substernal goiter may cause chronic ventilatory failure. Thyroidectomy should not be delayed because of concern regarding ventilatory failure. ACKNOWLEDGMENT: The writers thank Eleanor Strako for secretarial assistance in preparation of the manuscript; and Frank Danek for technical assistance in the Bow-volume curve studies.
REFERENCES 1 Jauregui R, Lilker E, Bayley A. Upper obstruction in enlarged goiter. JAMA 1977; 238:2163-66 2 Torres A, Arroyo J, Kastanos N, Estopa R, Augusti-Vidal A. Acute respiratory failure and tracheal obstruction in patients with intrathoracic goiter. Crit Care Med 1983; 11:265-66 3 Warren CP. Acute respiratory failure and tracheal obstruction in the elderly with benign goiters. Can Med Assoc J 1979; 121: 191-94 4 Segall D. Endothoracic goiter. Arch Intern Med 1968; 121:
353-55 5 Canham E, Sahn S. Recurrent '"suppressed" goiter causing upper airway obstruction. Am Rev Respir Dis 1982; 125:757-63 6 Rotman H, Liss M, Weg J. Diagnosis of upper airway obstruction by pulmonary function testing. Chest 1975; 68:796-99 7 Miller R, Hyatt R. Obstruction lesion of the larynx and trachea: clinical and physiologic characteristics. Mayo Clin Proc 1969; 44:145-61 Advanced Upper AJrway Obstruction due to Goiters (Karbcwltz et til)
8 Shim C, Corro P, Park S, William M. Pulmonary function studies in patients with upper airway obstruction. Am Rev Respir Dis 1972; 106:233-38 9 Shambaugh GE, Seed R, Korn A. Airway obstruction in substernal goiter, clinical and therapeutic implications. J Chron Dis 1973; 26:737-43 10 Voegel LD, Hagood MF, Yarborough DR. Benign goiter as a cause of post-intubation airway obstruction. S Med J 1973;
66:1304-05
11 Levy AM, Thsakin BS. Hypertrophied adenoids causing pulmonary hypertension and congestive heart failure. N Eng! J Med 1967; 277:506-16 12 Lefrak SA, Stevens PM, Howell JF. Respiratory insufficiency due to tracheal compression by an aneurysm of the ascending transverse and decending aorta. J Thorac Cardiovasc Surg 1972; 63:956-61
Current Topics In Pulmonary
Disease
The American Lung Association of Pennsylvania and the Pennsylvania Thoracic Society and Pennsylvania Society for Respiratory Therapy, will sponsor this postgraduate course at the Marriott Hotel (City Line Avenue), Philadelphia, March 12-14. For information, contact Ms. Kaye M. Miller, Pennsylvania Thoracic Society, 5114 Lancaster Street, Harrisburg 17lll {717:564-4850).
Postgraduate
Course in Bronchoesophagology
Chevalier Jackson Clinic ofTemple University School of Medicine, will present this course at the Clinic, 3440 North Broad Street, Philadelphia, March 18-22. For information, contact Charles M. Norris, M.D., 3440 North Broad Street, Philadelphia 19140 {215:223-4843).
CHEST I 87 11 I JANUARY, 1985
21
Five patients with advanced upper airway obstruction due to goiter were identified in our institution. All had symptoms of respiratory insufficiency to such a degree that surgery was clearly indicated. FUnctional characteristics of this
group were compared with prior series of goiter patients who had less severe respiratory symptoms. A peak inspiratory flow less than 1.5 Usee characterized this group who required surgery.
airway obstruction (UAO) caused by goiter U pper varies from asymptomatic patients with abnormal flow-volume curves, 1 to reports of acute respiratory failure. 2-5 It became apparent after study of our index patient (case 1) with chronic ventilatory failure due to a substernal goiter, that there was only anecdotal reporting of patients with advanced UAO due to goiter. Specific physiologic criteria characterizing those patients who required surgery for goiter is absent from the screening study of the flow-volume curve and goiter as reported by Jauregui et al. 1 Thus, after our index case, we prospectively screened all How-volume curves in our laboratory and all patients with respiratory insufficiency consultations for UAO due to goiter. We identified five patients with goiters severe enough to require surgical correction because of symptomatic airway compromise, and flow-volume curves typical of U AO according to the criteria of Rotman et al. 6 These patients were identified over a three-year period. All studies were performed with an automated mass flow meter. We believe the characteristics of this group offer a better insight into this subset of patients with severe UAO and goiter.
-
c.) Q)
CASE
1
A 63-year-old man was admitted for progressive dyspnea and ventilatory failure. He was a heavy smoker for 40 years. He had noted dilated veins on his chest for two years. On admission, he was in moderate respiratory distress. Respirations were 20/min, blood pressure, 170/100 mm Hg, pulse, 86 per minute, and he was afebrile. His thyroid was enlarged, nodular, and was estimated at 75 g. Examination of the chest revealed bilateral basilar rales. There was no definite stridor or wheezing. Heart sounds were normal. Laboratory studies were most remarkable for evidence of chronic hypercapnia (Table 1). This was initially assumed to be due to chronic obstructive lung disease. The chest roentgenogram revealed a superior mediastinal mass extending to the thoracic inlet and *From the Pulmonary Section, Department of Medicine, Booth Memorial Medical Center, Flushing, NY. Manuscript received April30; revision accepted July 6. Reprint requests: Dr: Karbowitz, Booth Memorial Hospital, 56-45 Main Street, Flushing, New York 11355
18
0 1 2
I
(I)
........
--
0
(I)
1
2
I
34
~
Q)
@
....J
w
1-
<[
0::
3':
0
....J
LL. CASE REPORTS
®
4 3 2 1
7 6 5 4 3 2 1
0
1 2 3 4 5
0
1
2
3
4
VOLUME (Liters) FIGURE 1. Flow-volume curve of patient 1 before (A) and after (B) removal of substernal thyroid. Advanced Upper Airway Obstruction due to Goitels (Karbowltz et a/)
Table !-Clinical and Physiologic Featun1s q{Goiters Causing Severe Upper Ainoay Obstruction* Patient
Clinical Presentation Ventilatory failure Stridor
1 2
Pathology Multinodular goiter Multinodular goiter Multinodular goiter
Enlarging goiter despite throxine Follicular Choking adenoma sensation stridor Multinodular Ventilatory failure goiter stridor Mean befOre surgery SD Mean befOre surgery SD Statistical significance by paired Student's
3
4
5
lA>cation Substernal Substernal Cervical
Cervical
Substernal
PaC02, mmHg
PEF Us
PIF Us
b 57 b 7.36 a44 a 7.40 b40 b 7.38 a 7.45 a 37 bNA bNA aNA aNA
4.4 6.2 2.3 4.5 5.5 5.8
1.7 1.7 4.3 3.7 3.5 1.3 1.9 1.2 2.3 3.1 1.2 3.8 3.2 4.2
bNA a30
bNA a 7.44
5.2 3.9
1.4 1.8
2.5 2.3
b59 a43
b 7.38 a 7.50
NA NA
NA NA NA
NA NA
4.35 1.44 5.10 1.08 NS
1.40
2.47
pH
b a t-test
.22 2.90 1.10 p<0.10
VE50 Us
VJ50
Us
VES0NJ50
1.5
2.1 0.6 2.4
1.2 1.0 1.6 1.5 6.3 1.8
1.5 1.7 1.7
1.4
NA NA
.95 3.33 .82 NS
NA 1.20 .42 2.43 .77 p<0.10
2.70 2.41 1.43 .33 NS
*Definition of abbreviations: PIF, peak inspiratory flow; PEF, peak expiratory flow; VE50, maximum expiratory flow at 50% of vital capacity; VJ50, maximum inspiratory flow at 50% of vital capacity; b, befOre surgery; a, after surgery; NS, not significant; NA, not available. deviating the trachea to the left. The initial flow-volume curve demonstrated evidence ofUAO (Fig IA). Thyroid scan with technetium 99m demonstrated an enlarged thyroid with mediastinal extension. During his hospital stay, he was initially treated with aminophylline and bronchodilator inhalation. During this therapy, his PaC02 remained above 55 mm Hg. It was decided that the goiter itself could be the cause of the chronic ventilatory failure. The patient underwent a total thyroidectomy with removal of a benign multinodular goiter of 175 g through a cervical incision. Postoperatively, the patient was fully relieved of dyspnea. The PaC02 one month postoperatively was 44 mm Hg. Repeat flow-volume curves one month postoperatively showed correction ofUAO (Fig 18). CASE
2
A 67-year-old woman was admitted for evaluation of progressive dyspnea on exertion. The patient was noted to have stridor after walking one block to the medical clinic. Physical examination demonstrated a small cervical goiter. Chest roentgenograms showed a widened mediastinum superiorly, without obvious change for the past three years. Roentgenographic interpretation was initially that of tortuous great vessels. Technetium scans confirmed a goiter in the neck extending through the thoracic inlet into the substernal area. The CT scans confirmed a marked narrowing of the trachea. Flowvolume curves revealed the pattern of UAO. After removal of her substernal goiter, all symptoms disappeared. CASE
3
This 45-year-old woman was admitted fur thyroidectomy fur a cervical goiter that was enlarging despite thyroxine therapy. The patient had choking sensations but no consistent dyspnea. A chest roentgenogram showed a mass at the thoracic inlet with a narrow tracheal lumen. The flow-volume curve confirmed variable extrathoracic UAO. After removal of the goiter, there were no further episodes of choking. CASE
4
A 78-year-old woman with cervical goiter that had been asymptomatic fur many years, was admitted with episodes of choking and stridor over a one-year period. On examination, a 5 X 6 em goiter was
palpated. Tracheal tomograms showed intrinsic compression. The Bow-volume curve confirmed UAO. After removal of the goiter, she was asymptomatic and comfOrtable. CASE
5
This 89-year-old man was admitted because of progressive dyspnea of several weeks' duration. He was a cigar smoker. The dyspnea was initially assumed to be due to chronic obstructive lung disease. However, stridor was heard upon examination, and dilated veins were obvious across both shoulders. A chest roentgenogram demonstrated a substernal mass with widening of the superior mediastinum. He could not perform How-volume curves. Despite his age, he was advised to have the goiter removed because this was the single factor limiting his ability to function. He refused, until he developed acute respiratory failure requiring tracheal intubation and mechanical ventilation. It was felt that the patient could not be extubated until the goiter was removed. After surgery, he was promptly extubated and breathed without difficulty. RESULTS
All five patients had clear clinical requirements for surgical correction of a goiter. Three had stridor, two had acute exacerbation of ventilatory failure, and one had a goiter enlarging despite suppressive therapy with thyroxine. Four were multinodular goiters, and one was a follicular adenoma (Table 1). The substernal goiters were removed by cervical incisions. There was no postoperative complication. The mean peak expiratory flow (PEF) was 4.4 liters per second (Us) before surgery, and did not significantly change afterward (Table 1). The mean peak inspiratory flow (PIF) was 1.40 Us before surgery and doubled afterward (p<0.10). Similarly, the mean maximum flow at 50 percent of vital capacity during inspiration (VI50) doubled (p<0.10). The two patients with hypercapnia corrected postoperatively. CHEST I 87 I 1 I JANUARY, 1985
19
Table 2-Compariaon of Pretreatment Flow8: Patients with Severe Goit1'0U8 Upper Ainoay Obstruction va Unaelected Goiter Population•
Flows
Present Study (n=4) Mean±SD
Reference Study' (n=ll) Mean±SD
p Value by Paired Student's t-test
PEF VE50 VI50
4.35± 1.44 2.47±0.95 1.20±0.42
4.46± 1.99 3.15± 1.57 2.96±0.96
NS NS
<.05
•Definition of abbreviations: PEF, peak expiratory flow; VE50, maximum expiratory Bow at 50% of vital capacity; VI50, maximum inspiratory flow at 50% of vital capacity; NS, not significant.
DISCUSSION Our study demonstrates that a mean PIF of 1.5 Us identifies a subset of patients with goiter and UAO who require urgent surgery. This is consistent with the results of other clinical and experimental studies. 1·7 •8 Jauregui et al' reported a mean VI50 of2.96 Us in a group of 11 patients treated for goiter. Of this group, nine were treated successfully medically and two required surgical correction. His report did not elaborate as to which patients required surgery. This corresponds to a VI50 more than double that of the four patients in our group who performed flow-volume curves (Table 2). This difference is significant (p<0.05) even in the small sample sizes of both groups. Miller and Hyate studied the flow-volume curves of seven healthy adult men while interposing a progressively narrowed orifice from 13 mm internal diameter (ID) to 4 mm ID. Flattening of the flow-volume curves became apparent at 6 mm ID. In changing the orifice from 6 mm ID to 4 mm ID, the PIF decreased from 3. 0 Us to 1.8 Us. This matches closely the difference between the VI50 of 2. 96 Us of Jauregui et al and our group of patients with severe symptoms of UAO and VI50 of 1.20 Us. This also is consistent with the report of Shim et al8 who found a maximum midinspiratory flow (MMIF) of less than 1.4 Us in patients with chronic UAO and significant limitation of function. One should note that PIF, VI50, and MMIF should all be fairly similar in patients with a flat inspiratory limb of the flow-volume curve. In our series of goiters, symptomatic UAO is correlated with the flow-volume curve. Shambaugh et al9 have shown that patients with goiters can remain asymptomatic for years and progress within days to lifethreatening airway obstruction. The weight of the excised gland did not correlate with the degree of obstruction. Therefore, patients should have frequent flow-volume curves to monitor for incipient UAO. A PIF or VI50 less than 1.5 Us is an indication for immediate thyroidectomy to avoid acute ventilatory failure. Careful review of the literature has failed to reveal a prior report of chronic hypercapnia solely due to 20
substernal goiter, such as we have demonstrated in case 1. Despite vigorous medical therapy with bronchodilators for possible intrinsic airway disease of the lung, there was no improvement in alveolar hypoventilation until after thyroidectomy. Numerous reports2.3.5.9.to have described acute respiratory failure from benign goiters. Voegel et al'0 reported benign goiter as a cause of postintubation airway obstruction. Canham and Sahn5 described a goiter suppressed by thyroxine causing rapidly progressive respiratory failure. These reports have emphasized acute respiratory failure in patients without previous flow-volume curves. In our series, case 1 demonstrates chronic ventilatory failure. This may represent an intermediate stage between an abnormal flow-volume curve and acute respiratory failure. This once again demonstrates the importance of serial flow-volume curves and frequent clinical evaluations. Other obstructing lesions of the upper airways, such as enlarged tonsils and adenoids, 11 have been documented as causing chronic UAO, pulmonary hypertension, and cor pulmonale in the pediatric population. In the adult, UAO and chronic ventilatory failure have been reported due to an aneurysm of the ascending aorta with normalization following surgery. 12 These lesions of the upper airway associated with chronic hypoventilation share two features. They are outside the tracheal lumen, either in the pharynx or in the mediastinum; and they are benign. These characteristics cause an extremely slow and indirect increase in the airway resistance as compared to intraluminal lesions. This may allow time for adaptive hypoventilation without acute dyspnea. Our index patient (case 1), clearly illustrates that substernal goiter may cause chronic ventilatory failure. Thyroidectomy should not be delayed because of concern regarding ventilatory failure. ACKNOWLEDGMENT: The writers thank Eleanor Strako for secretarial assistance in preparation of the manuscript; and Frank Danek for technical assistance in the Bow-volume curve studies.
REFERENCES 1 Jauregui R, Lilker E, Bayley A. Upper obstruction in enlarged goiter. JAMA 1977; 238:2163-66 2 Torres A, Arroyo J, Kastanos N, Estopa R, Augusti-Vidal A. Acute respiratory failure and tracheal obstruction in patients with intrathoracic goiter. Crit Care Med 1983; 11:265-66 3 Warren CP. Acute respiratory failure and tracheal obstruction in the elderly with benign goiters. Can Med Assoc J 1979; 121: 191-94 4 Segall D. Endothoracic goiter. Arch Intern Med 1968; 121:
353-55 5 Canham E, Sahn S. Recurrent '"suppressed" goiter causing upper airway obstruction. Am Rev Respir Dis 1982; 125:757-63 6 Rotman H, Liss M, Weg J. Diagnosis of upper airway obstruction by pulmonary function testing. Chest 1975; 68:796-99 7 Miller R, Hyatt R. Obstruction lesion of the larynx and trachea: clinical and physiologic characteristics. Mayo Clin Proc 1969; 44:145-61 Advanced Upper AJrway Obstruction due to Goiters (Karbcwltz et til)
8 Shim C, Corro P, Park S, William M. Pulmonary function studies in patients with upper airway obstruction. Am Rev Respir Dis 1972; 106:233-38 9 Shambaugh GE, Seed R, Korn A. Airway obstruction in substernal goiter, clinical and therapeutic implications. J Chron Dis 1973; 26:737-43 10 Voegel LD, Hagood MF, Yarborough DR. Benign goiter as a cause of post-intubation airway obstruction. S Med J 1973;
66:1304-05
11 Levy AM, Thsakin BS. Hypertrophied adenoids causing pulmonary hypertension and congestive heart failure. N Eng! J Med 1967; 277:506-16 12 Lefrak SA, Stevens PM, Howell JF. Respiratory insufficiency due to tracheal compression by an aneurysm of the ascending transverse and decending aorta. J Thorac Cardiovasc Surg 1972; 63:956-61
Current Topics In Pulmonary
Disease
The American Lung Association of Pennsylvania and the Pennsylvania Thoracic Society and Pennsylvania Society for Respiratory Therapy, will sponsor this postgraduate course at the Marriott Hotel (City Line Avenue), Philadelphia, March 12-14. For information, contact Ms. Kaye M. Miller, Pennsylvania Thoracic Society, 5114 Lancaster Street, Harrisburg 17lll {717:564-4850).
Postgraduate
Course in Bronchoesophagology
Chevalier Jackson Clinic ofTemple University School of Medicine, will present this course at the Clinic, 3440 North Broad Street, Philadelphia, March 18-22. For information, contact Charles M. Norris, M.D., 3440 North Broad Street, Philadelphia 19140 {215:223-4843).
CHEST I 87 11 I JANUARY, 1985
21