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In conclusion, CSR that occurs during sleep in patients with severe CHF is eliminated by HT.

This is a retrospective analysis of 73 patients with non-oat cell carcinoma of the lung presenting as a Pancoast tumor. All patients were treated with curative intent between October 1964 and September 1987 (minimum follow-up 2 years). The treatment plan consisted of preoperative radiation therapy (usually 3000 cGy in 2 weeks or 4500 cGy in 5 weeks) in 41 patients and radiation therapy alone (usually 6500–7000 cGy in 6.5–8.0 weeks) in 32 patients. In general, radiation therapy alone was reserved for poor-prognosis patients (extensive disease or medical inoperability). Although 41 patients were initially scheduled to receive preoperative radiation therapy and surgery, the surgery was not performed in 12 cases (29%) because of patient refusal (4 patients), poor response to radiation therapy (4 patients), distant metastasis (2 patients), or debilitation (2 patients). Separate calculations were carried out for the patients who completed the surgery as planned (preoperative radiation therapy and surgery) and the entire group originally scheduled for combined-modality therapy. There was no significant difference in the absolute or cause-specific survival rates between treatment groups, but severe complications were significantly more common in patients receiving combined therapy.

Study Objective to determine if asymptomatic snorers have smaller pharyngeal volumes than age- and height-matched nonsnorers. Design we recruited asymptomatic heavy snorers and nonsnorers for a study. Each snorer was matched by age (±3 years) and height (±2 inches) with a nonsnorer. The nonsnorers were required to be near ideal body weight. All volunteers underwent overnight polysomnography, pulmonary function testing, and magnetic resonance imaging of the pharynx while awake. The volume of the pharynx was determined by a computer with data input from a digitizing instrument. Setting Veterans Administration Hospital and University of Florida Teaching Hospital Participants Nine volunteers were recruited for both the snorer and nonsnorer groups. Each participant was paid $50. There were no interventions. Measurements and results There were no differences in sleep variables between the two groups. There was also no significant difference between pharyngeal volumes for the two groups. Conclusions The volume of the pharynx in asymptomatic snorers is similar to the volume in age- and height-matched nonsnorers. (Chest 1991; 99:49–53)

A controversy exists over whether or not preoperative exercise testing can predict postthoracotomy complications. This study was designed to evaluate the usefulness of a presurgical exercise protocol in patients with lung disease, but no evidence of cardiac disease. Seventy patients underwent baseline pulmonary function testing and split function perfusion studies, when indicated, to calculate predicted postoperative pulmonary function. Noninvasive data were incrementally collected from 17 patients by using a treadmill exercise tolerance test that was designed to elicit maximal performance. Inhaled and exhaled gas flow and, volume, the partial pressure of O 2 and CO 2 , maximal O 2 consumption (VO 2 max), and maximal minute ventilation (V E Max) were measured. The breathing and heart rate reserves were calculated by standard formulae in an attempt to separate cardiac from pulmonary exercise limitation. Two patients had postoperative cardiopulmonary complications after thoracotomy and lung resection, and six patients had noncardiopulmonary complications. There was no significant prognostic relationship among VO 2 max, V E max. maximum O 2 pulse, and the incidence of postoperative cardiopulmonary complications. The percentages of predicted V E max and predicted maximum heart rate were related to the occurrence of total complications, but not specifically to cardiopulmonary complications. The results emphasize the difficulty in attempting to exercise thoracotomy candidates with chronic lung disease to maximal performance. Excluding patients from further surgical consideration because of exercise limitation is not feasible based on these data.

Chronic low flow oxygen is useful therapy for patients with chronic obstructive lung disease who are crippled by hypoxemia despite optimal programs of usual respiratory care. Patients should be considered for chronic oxygen therapy who have (a) a resting Pao2 less than 55 mm Hg while breathing room air; or (b) profound tissue hypoxemia measured by mixed venous Pao2 and suggested by symptoms such as cor pulmonale and congestive heart failure; or (c) pulmonary hypertension or polycythemia even though daytime Pao2 is greater than 55 mm Hg. Arterial blood must be obtained to demonstrate hypoxemia and assess the benefits of oxygen therapy. Patients on chronic oxygen must remain under close medical supervision. There are no absolute contraindications to chronic oxygen therapy, other than refusal of the patient to quit smoking. Complications of therapy appear to be negligible. The exciting suggestion of improved prognosis in patients with chronic obstructive lung disease on oxygen therapy and the possibility of delaying the long-term sequelae of chronic respiratory failure bear careful watching in the future.

Twelve patients with hypoxemia associated with severe chronic obstructive pulmonary disease were treated with continuous portable oxygen therapy and have been followed up for a mean period of 25.2 months at sea level. Pulmonary function testing has revealed no further significant deterioration at long-term follow-up (17 months). After oxygen therapy was initiated, arterial carbon dioxide tension increased slightly, but decreased to pretreatment levels when patients were allowed to breathe room air. The electrocardiogram, which was unchanged at one month, has shown some reversal of cor pulmonale in five patients. Six patients have died, yielding a 56 percent survival rate at two-and-one-half years by the life table analysis. Five patients were autopsied, with possible oxygen toxicity being present in only one. The quality of life in our patients was improved and was especially represented by a reduction in hospital admissions for respiratory illness. We believe that continuous oxygen therapy is beneficial and worthwhile economically in certain patients.

A simple, practical method is described for estimating unilateral lung function. Overall lung function is multiplied by right-left fractional perfusion estimated from a quantitative technetium ferric hydroxide macroaggregate lung scan. The calculated function attributed to the lung to be resected is then subtracted from the overall pulmonary function. The data from 13 patients indicate that the following postpneumonectomy functions can be predicted: forced vital capacity, forced expiratory one second volume, maximum voluntary ventilation, functional residual capacity, total lung capacity and diffusing capacity. The precedures described are available in most hospitals and represent a practical alternative to classic bronchospirometry, xenon radiospirometry and unilateral pulmonary artery balloon occlusion in the estimation of split lung function.

We evaluated 33 high-risk patients before pneumonectomy, all of whom had a forced expiratory volume in one second (FEV1) of less than 2.0 L before surgery. A quantitative perfusion lung scan was used to assess the right-left distribution of blood flow. A predicted postoperative FEV1 was calculated from the information on the lung scan and the preoperative FEV1. If this calculated value exceeded 800 ml, the patient was physiologically cleared for surgery up to and including a pneumonectomy. Surgery was otherwise believed to be contraindicated in the absence of studies using balloon occlusion. Perioperative mortality (less than or equal to 30 days after surgery) was found to be 15 percent (5/33). In surgery of this magnitude, we find this to be an acceptable percentage of mortality and have continued to use these simple physiologic criteria to determine whether a patient can tolerate pneumonectomy.

A case is presented of pathologically proved unilateral pulmonary edema due to uremia and blood transfusion. The lung that was spared had been denervated by a thoracic sympathectomy eight years earlier. That this denervation may have been responsible for the unilaterality of the pulmonary edema is suggested by experimental evidence supporting a neurogenic etiology of noncardiac pulmonary edema. The literature is briefly reviewed, and implications for therapy are discussed.

Four patients with diffuse pulmonary sarcoidosis were treated with alternate-day corticosteroid therapy. Prompt resolution of physiologic, radiologic and symptomatic evidence of disease occurred without significant side-effects of therapy. While corticosteroid therapy may not alter the longterm prognosis in sarcoidosis, prompt complete remission can be induced safely with an alternate day regimen. Such therapy is advised for acute, symptomatic pulmonary involvement.

The utility of the apnea index (number of apneic events per hour of sleep) in diagnosing sleep apnea syndrome is reviewed. Data from currently extant reports indicate that many otherwise normal, aging subjects may be classified as having sleep apnea syndrome based on the current diagnostic threshold of five apneic episodes per hour. A χ2 analysis suggests a relationship between age and level of sleep apnea. Several other reports indicate that use of a threshold of five apneic episodes per hour does not reliably predict increased health risk or somnolence in aging subjects. Adjustment of the apnea index, based on studies of aging normal subjects and of aging patients with sleep apnea syndrome is necessary to ensure reliable results in clinical and research applications.

Twenty-one postmenopausal women were monitored for sleep-disordered breathing and nocturnal oxygen desaturation to evaluate the contribution of progestational hormones to the occurrence of these sleep events. For approximately one month 11 subjects received 30 mg of medroxyprogesterone (MPG) daily, and 10 received placebo tablets in a randomized, double-blind controlled study. Respiration, saturation and electroencephalography were monitored during one night of sleep before and one night after therapy. Contrasted with the low incidence of disordered breathing and desaturation in premenopausal women, 71 percent of the postmenopausal women had such events. In the placebo-treated group, all measured variables of sleep and breathing were identical on the two nights, which suggested that the findings of a single night of sleep monitoring may be representative of other nights of sleep. Although several subjects appeared to show improvement with MPG, only the maximum duration of apnea was significantly reduced the second night (p less than 0.03).21 postmenopausal women were monitored for sleep-disordered breathing and nocturnal oxygen desaturation to evaluate the contribution of progestational hormones to the occurrence of these sleep events. For approximately one month, 11 subjects received 30 mg of medroxyprogesterone (MPG) daily, and 10 received placebo tablets in a randomized, double-blind controlled study. Respiration, saturation and electroencephalography were monitored during one night of sleep before and one night after therapy. Contrasted with the low incidence of disordered breathing and desaturation in premenopausal women, 71% of the postmenopausal women had such events. In the placebo-treated group, all measured variables of sleep and breathing were identical on the 2 nights, suggesting that the findings of a single night of sleep monitoring may be representative of other nights of sleep. Although several subjects appeared to show improvement with MPG, only the maximum duration of apnea was significantly reduced the 2nd night (p0.03). The study supports the observation that disordered breathing and desaturation are similarly frequent in postmenopausal women and in men.

Twenty patients with mild to severe chronic obstructive pulmonary disease received ultrasonic nebulization to assess the danger of short-term changes in blood gas levels during this therapy. The status of arterial oxygenation was monitored during 20 minutes of therapy and for 20 minutes following therapy. In nine patients with periodic studies of arterial blood, the mean change in arterial oxygen pressure from base line was a decrease of 0.8 mm Hg at ten minutes into therapy, 2.8 mm Hg at the conclusion of therapy, and 2.9 mm Hg 20 minutes after therapy. In all 20 patients, ear oximetric studies showed only a small mean change at ten minutes into therapy, at the end of therapy, and at 20 minutes after therapy. Changes in the status of arterial oxygenation during and after therapy with ultrasonic nebulization in a group of patients with chronic obstructive pulmonary disease are generally small and of no statistical and limited clinical significance; however, alarming falls in arterial oxygenation can occur and cannot be predicted by base-line testing of pulmonary function or studies of arterial blood. It would be prudent to monitor patients with chronic obstructive pulmonary disease during therapy with ultrasonic nebulization or to withhold therapy altogether.

Oxygen desaturation occurs during sleep in some patients with COPD. To investigate the effects of these hypoxemic episodes on the pulmonary vasculature, we studied four patients with our routine polysomnographic techniques and simultaneously recorded pulmonary artery pressure. In all four subjects, nocturnal episodes of desaturation were accompanied by elevations in the pulmonary artery pressure. Low flow oxygen abolished the drops in arterial oxygen saturation (but not the breathing abnormalities) and no elevations in the PA pressure were observed. We postulate that in some COPD patients these initially transient events may lead to sustained pulmonary hypertension and cor pulmonale. Nocturnal oxygen therapy may be indicated in more patients than previously suspected and may prevent the development of cor pulmonale.

We monitored arterial oxygen saturation (SaO2) in 10 patients with severe chronic obstructive lung disease during 24 h of breathing room air followed by 24 h of breathing two litres of oxygen per minute. Three subjects without chronic obstructive lung disease were monitored while breathing room air. Greatest declines in SaO2 occurred during sleep, with intermittent decreases as great as 44% saturation (range, 12% to 44% saturation. Baseline SaO2 was significantly higher while patients breathed low-flow oxygen (94% versus 86% saturated), and declines in SaO2 during sleep were less noteworthy (1% to 27% saturation). Subjects without chronic obstructive lung disease showed declines in SaO2 of much lesser magnitude (3% to 11% saturation) with sleep. These declines were not primarily due to alveolar hypoventilation. Our data indicate that there are patients with chronic airways obstruction who suffer profound intermittent desaturation at night that can readily be relieved with low-flow oxygen administration.

A patient with chronic interstitial pneumonia was treated with steroids with excellent results. Electron microscopic examination of a lung biopsy taken before treatment showed the functional defect to be associated with a gross increase in the width of the anatomic barrier to gaseous diffusion into the blood. A peculiar sudanophilic and oleophilic inclusion was identified in the cytoplasm of his alveolar macrophages, and it is postulated that this material, which is of obscure origin, was the primary lung irritant.

A 60-year-old white man with chronic bronchitis was noted to develop acute respiratory failure and metabolic acidosis four days after being started on methazolamide (Neptazane) for an ophthalmologic problem. The patient was intubated with ventilator support and improved after his metabolic acidosis resolved. Caution is emphasized in the use of carbonic anhydrase inhibitors in patients with obstructive airway disease.

The second case of subcutaneous implantation of cancer following thoracentesis is reported. This type of metastasis has also been seen with percutaneous needle biopsy of the pleura or lung. This potential complication does not contraindicate thoracentesis.

In Reply.— Dr Frazier has rendered an opinion concerning "who needs pulmonary function studies." I tend to agree with his opinion that the allergic asthmatic child should be studied prior to surgery if at all possible. On the other hand, we never know whether our opinions are correct until some sort of study has been constructed and these opinions prospectively evaluated. To the best of my knowledge, there has been no study of preoperative pulmonary function testing in children. Without such studies, the questions of which abnormalities, how severe they must be, and what sort of operations are affected remain unanswered. This was the main point of my COMMENTARY. Dr Frazier may know who needs pulmonary function testing, but I am not sure that I absolutely know at the present time.

PREOPERATIVE pulmonary function testing is easy to perform. Setups for spirometry are cheap and simple, and automated systems are available to compute all varieties of measurement. Today's problems for the clinician are "What does preoperative pulmonary function testing mean?" and "Who needs these studies?" The patient with bronchogenic carcinoma often has concomitant obstructive airway disease, since cigarette smoking is a common factor. If a surgeon contemplates resection of the carcinoma, pneumonectomy looms as a possibility. If the possibility of removing an entire lung exists, the assessment of pulmonary function is mandatory. Consequently, much has been written about preoperative assessment of the pneumonectomy candidate. Assessment for Pneumonectomy The understanding of preoperative assessment for pneumonectomy has proceeded in three phases. First to be recognized was that reduction oftotalfunction made removal of a lung hazardous.1-3The amount of reduction (and by what test) and the hazard of the operation were

Excerpt To the editor: In November 1987, the American Board of Internal Medicine will administer a special certifying examination in critical care medicine. To qualify to sit for this examination, ...

In a middle-aged man with cardiopulmonary failure secondary to severe kyphoscoliosis, skeletal traction produced improvement by roentgenographic, functional, and clinical criteria. Although an attempt to perpetuate this improvement by surgical spine correction was unsuccessful, it is thought that these therapeutic maneuvers should be attempted again in the absence of other definitive therapy.