David J. Kanarek

Postpneumonectomy syndrome: Diagnosis, management, and results☆

Airway obstruction may be caused by extreme mediastinal shift and rotation after right pneumonectomy or after left pneumonectomy in the presence of a right aortic arch. Eleven adults (aged 18 to 58 years) with severe symptoms were treated surgically between 5 months to 17 years after pneumonectomy (7 right, 4 left). An initial patient with only one functional lobe was treated unsuccessfully by aortic division and bypass graft. Ten underwent mediastinal repositioning. After two recurrences prostheses were used to maintain mediastinal position. Five patients who underwent such repositioning are doing well from 5 months to more than 5 years later. One died 1 month after operation probably of pulmonary embolism. One who showed residual airway collapse after operation has some recurrent obstruction. Three other patients who showed severe malacic obstruction of the airway after mediastinal repositioning variously underwent aortic division with bypass graft and tracheal and bronchial resection. One is well almost 6 years later. Two died postoperatively. Occurrence of the syndrome is unpredictable. Where malacic changes have not occurred, mediastinal repositioning may reasonably be expected to correct obstruction. Optimal treatment for concurrent severely malacic airways is unclear.

Toxicity of thoracic radiotherapy on pulmonary function in lung cancer

Physiological changes in pulmonary function (PF) as a result of radiation therapy (RT) or radiation therapy plus chemotherapy (RT + CT) for unresectable lung cancer were evaluated in an ongoing prospective study and an attempt was also made to define a guideline which can be used to minimize adverse effect of RT on pulmonary function before RT is given. The study design consisted of: (a) standard overall pulmonary function test (PFT); (b) regional PFT, i.e. a quantitative analysis of regional distribution of ventilation, perfusion and volume using 13N and a positron camera before RT; and (c) follow-up studies of standard PFT every 6 months for 3 years after RT or RT + CT. Predicted post-RT PF prior to RT was calculated by a formula: predicted FEV1 after RT = FEV1 before RT x (1 - an average of the percent of ventilation and perfusion contributed by lung tissue within the RT treatment volume). A total of 267 patients with unresectable, but still potentially curable lung cancer by RT were entered into this study, and 135 patients who were free of recurrence underwent repeat studies. Loss of PF as a result of RT is closely related to the degree of PF reserve prior to RT. Patients with FEV1 > 50% of the predicted showed a statistically significant decrease in FEV1, FVC, MBC, peak expiratory flow rate and DLCO, i.e. a 22% loss of the initial value. Airway resistance was increased by 31%. Two-thirds of this group of patients showed a decrease in PF as predicted by the above formula. For patients with limited PF reserve defined by FEV1 < 50% of the predicted, the pattern of PF loss after RT was quite different. An improvement in PF although it was < or = 10%, contrary to the prediction, was noted in 50% of patients, and another 37% of patients showed a small decrease in PF (< or = 10% of the initial value). Only 13% of patients showed a loss of pulmonary function as predicted by regional PF data. Patients with a significant shift (> 10%) of ventilation and/or perfusion to the uninvolved side of the lung by centrally located primary tumor or involved lymph nodes showed an increase in PF in 60% of patients after RT, and another 20% of patients showed a minor decrease in PF (< 10% of the initial value). Only 20% of these patients showed a decrease in pulmonary function as predicted by regional PF data. Guidelines for minimizing adverse effect of RT on PF, which are based on the initial PF reserve and regional PF data, are presented.

EFFECT OF POSTOPERATIVE RADIOTHERAPY ON CHANGES IN PULMONARY FUNCTION IN PATIENTS WITH STAGE II AND IIIA LUNG CARCINOMA

To assess the pulmonary tolerance to postoperative radiotherapy (RT) in patients with resected lung carcinoma, a prospective study was begun in January 1977, which consisted of (a) initial pulmonary function test (PFT) and arterial blood gases (ABG) at 1 month after surgery, and before beginning of postoperative RT, and (b) follow-up PFT and ABG 1 year after postoperative RT and then every year thereafter. As of December 1987, 137 patients have been enrolled into this study, and 71 patients who were free of recurrence were subjected to the follow-up PFT and ABG. The remaining 66 patients were unable to complete the follow-up studies because of recurrent carcinoma in 60, refusal to participate in the study in 5 patients even in the absence of significant respiratory symptoms, and progressive asbestos-related pleural thickening in 1 patient. The patient characteristics were as follows: Age ranged from 27 to 79 years with the median of 59 years; sex ratio was 1.4 to 1 for male to female; surgical procedures included lobectomy in 49 and pneumonectomy in 22 patients; tumor extent consisted of Stages T1-T2N1M0 in 44, T1-T2N2M0 in 9, and T3N0-N2M0 in 18 patients, respectively. Histologic types included squamous cell carcinoma in 26, adenocarcinoma in 42, small cell carcinoma in 1, and large cell carcinoma in 2 patients. Target volume for RT included the ipsilateral hilum, the mediastinum, and the thoracic inlet including both supraclavicular fossae. A total dose of 54 Gy was delivered in 1.8 Gy of daily fractions, 5 days per week over a period of 6 weeks. Contrary to expectation, there were minor changes in PFT indices in both lobectomy and pneumonectomy patients. The follow-up PFT in the lobectomy group showed small -3% to +2% changes in mean values of ventilatory indices, lung volume, and ABG. The follow-up PFT in the pneumonectomy group also showed small -9% to +13% changes in mean values of ventilatory indices, lung volume, and ABG. Sixteen patients have had more than one PFT during the follow-up period (2 years to 10 years), and there was no significant long term adverse effect of RT on PFT in this subset of patients. Lung scans assessing regional function, which were available in six patients, were not helpful in predicting changes in PFT indices as a result of postoperative RT.

Left ventricular ejection fraction response during exercise in asymptomatic systemic hypertension

To study the effect of mild-to-moderate elevations in diastolic blood pressure (BP) on systolic left ventricular (LV) function, 28 hypertensive patients and 20 normal subjects underwent upright exercise first-pass radionuclide angiography. All were asymptomatic, had normal rest and exercise electrocardiographic findings and no evidence of LV hypertrophy or coronary artery disease. LV function at rest was similar in the 2 groups, but with exercise hypertensive patients had a greater end-systolic volume (69 +/- 19 vs 51 +/- 19 ml, p less than 0.002) and lower ejection fraction (EF) (0.59 +/- 0.09 vs 0.72 +/- 0.07, p less than 0.0001), stroke volume (101 +/- 28 vs 130 +/- 36 ml, p less than 0.005) and peak oxygen uptake (23 +/- 7 vs 33 +/- 9 ml/kl/min, p less than 0.05). Hypertensive patients were separated into 3 groups: group 1-12 patients with an increase in EF with exercise greater than or equal to 0.05; group 2-7 patients with a change in EF with exercise less than 0.05; and group 3-9 patients with a decrease in EF with exercise greater than or equal to 0.05. Group 3 hypertensive patients were older, had a higher heart rate at rest and lower peak oxygen uptake. Rest LV function was similar in the 3 hypertensive subgroups, but exercise end-systolic volumes were higher in groups 2 and 3. Exercise thallium-201 images was normal in all but 1 of 14 hypertensive group 2 or 3 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Exercise testing in asymptomatic or minimally symptomatic aortic regurgitation: relationship of left ventricular ejection fraction to left ventricular filling pressure during exercise.

Exercise radionuclide angiography is being used to evaluate left ventricular function in patients with aortic regurgitation. Ejection fraction is the most common variable analyzed. To better understand the rest and exercise ejection fraction in this setting, 20 patients with asymptomatic or minimally symptomatic severe aortic regurgitation were studied. All underwent simultaneous supine exercise radionuclide angiography and pulmonary gas exchange measurement and underwent rest and exercise measurement of pulmonary artery wedge pressure (PAWP) during cardiac catheterization. Eight patients had a peak exercise PAWP < 15 mm Hg (group 1) and 12 had a peak exercise PAWP ≥ 15 mm Hg (group 2). Group 1 patients were younger and more were in New York Heart Association class I. Group 1 patients also had a higher mean rest ejection fraction (0.64 ± 0.08 vs 0.49 ± 0.13, p < 0.01, higher exercise ejection fraction (0.63 ± 0.10 vs 0.40 ± 0.18, p < 0.01), lower end-systolic volume (38 ± 13 vs 79 ± 36 ml/m2, p < 0.01) and higher peak oxygen uptake (24.9 ± 5.1 vs 16.6 ± 4.9 ml/kg/min, p < 0.01) than group 2 patients. However, the two groups had similar cardiothoracic ratios, changes in ejection fractions with exercise, and rest and exercise regurgitant indexes. Using multiple regression analysis, the best correlate of the exercise PAWP was peak oxygen uptake (r = −0.78, p < 0.01). No other measurement added significantly to the regression. When peak oxygen uptake was excluded, rest and exercise ejection fraction also correlated significantly (r = − 0.62 and r = −0.60, respectively, p < 0.01). Patients with asymptomatic or minimally symptomatic severe aortic regurgitation have a wide spectrum of cardiac performance in terms of the PAWP during exercise. The absolute rest and exercise ejection fraction and the level of exercise achieved are noninvasive variables that correlate with exercise PAWP in aortic regurgitation, but the change in ejection fraction with exercise by itself is not.

Exercise testing in aortic regurgitation: Comparison of radionuclide left ventricular ejection fraction with exercise performance at the anaerobic threshold and peak exercise☆

Abstract Serial radionuclide left ventricular ejection fractions (EF) were measured during graded supine exercise in 16 control patients and 35 asymptomatic or minimally symptomatic patients with severe aortic regurgitation (AR). Simultaneous pulmonary gas exchange analysis permitted determination of the anaerobic threshold, which is the point during exercise at which lactic acid begins to accumulate in the blood. The EF and oxygen uptake were measured at rest, anaerobic threshold and peak exercise. The mean EF (±1 standard deviation) in control patients increased from 0.65 ± 0.06 at rest to 0.73 ± 0.05 at anaerobic threshold (p 16 ml/ kg/min (Group I, n = 26) and

Radiation exposure from Chest CT: Issues and Strategies

Concerns have been raised over alleged overuse of CT scanning and inappropriate selection of scanning methods, all of which expose patients to unnecessary radiation. Thus, it is important to identify clinical situations in which techniques with lower radiation dose such as plain radiography or no radiation such as MRI and occasionally ultrasonography can be chosen over CT scanning. This article proposes the arguments for radiation dose reduction in CT scanning of the chest and discusses recommended practices and studies that address means of reducing radiation exposure associated with CT scanning of the chest.

Ventilatory response to carbon dioxide inhalation in depression.

The ventilatory response to carbon dioxide (CO2 response) was determined in 18 patients admitted to an inpatient service with endogenous depressive illness. Admission mean CO2 response value for the group was below the mean value for a control group. At the time of hospital discharge marked clinical improvement had occurred in depressive symptomatology; mean CO2 response had increased slightly and was no longer significantly below the control value. CO2 response deserves further investigation as a possible physiologic characteristic of certain depressed patients.

Regional edema formation in isolated perfused dog lungs.

Studies using gravimetric analysis of lungs of frozen animals have suggested that the differences in pulmonary microvascular pressure between non-dependent and dependent lung do not influence the formation of regional pulmonary edema. We wondered if the inability to detect variation in regional extravascular lung water (EVLW) was due to the slow freezing process and, therefore, reassessed the distribution of EVLW in vertically suspended isolated perfused dog lungs with a radioisotopic technique that does not require freezing. Total lung water (TLW), blood or intravascular lung water (FVLW), and EVLW were measured in absolute quantities using a positron camera and the positron-emitting isotopes CI5O as a blood label and H215 total lung water label. Mean isotopic TLW in 17 lungs that were normal or moderately edematous (wet:dry ratio < 7) was 142 ± 9 (SE) ml compared to the gravimetric estimate of 148 ± 7 ml (r = 0.92) and isotopic EVLW was 64 ± 6 ml compared to the gravimetric estimate of 70 ± 6 ml (r = 0.8). Analysis of the distribution of regional isotopically measured EVLW in the 17 lungs in various states of spontaneous edema formation revealed a small non-dependent to dependent, gravity-related increase in percent regional EVLW compared to percent regional TLW, which did not vary with the degree of edema in the lung. Serial measurements of absolute regional EVLW in four lungs during spontaneously developing edema also failed to show a disproportionate increase in accumulation of EVLW in any lung zone. Thus, despite the wide variation in microvascular hydrostatic pressure between-top and bottom of the vertical isolated lung, edema formation seems to be uniform. Circ Res 48:121-127, 1981

Case 48-1977

Presentation of Case A 58-year-old man was admitted to the hospital because of bilateral pleural effusions. Four years previously symptoms of a respiratory-tract infection developed, with a cough a...