VITamin D and OmegA-3 TriaL (VITAL) bone health ancillary study: clinical factors associated with trabecular bone score in women and men

We investigated the association of clinical variables with TBS at baseline in the bone health sub-cohort of the VITamin D and OmegA-3 TriaL (VITAL). Lower TBS was associated with female sex, aging, BMI ≥ 25 kg/m², SSRI use, high alcohol intake, and presence of diabetes; there was a trend towards significance between lower TBS and history of fragility fractures.

INTRODUCTION

We investigated whether TBS differs by sex, race, body mass index (BMI), and other clinical variables.

METHODS

The VITamin D and OmegA-3 TriaL (VITAL) is determining effects of vitamin D₃ and/or omega-3 fatty acid (FA) supplements in reducing risks of cancer and cardiovascular disease. In the VITAL: Effects on Bone Structure/Architecture ancillary study, effects of these interventions on bone will be investigated. Here, we examine the associations of clinical risk factors with TBS assessments at baseline in the bone health sub-cohort, comprised of 672 participants (369 men and 303 women), mean (± SD) age 63.5 ± 6.0 years; BMI ≤ 37 kg/m², no bisphosphonates within 2 years or other bone active medications within 1 year.

RESULTS

TBS was greater in men than women (1.311 vs. 1.278, P < 0.001) and lower with elevated BMIs (P < 0.001), higher age (P = 0.004), diabetes (P = 0.008), SSRI use (P = 0.044), and high alcohol intake (P = 0.009). There was a trend for history of fragility fractures (P = 0.072), and lower TBS. TBS did not vary when analyzed by race, smoking, history of falls, and multivitamin or caffeine use.

CONCLUSIONS

Lower TBS was associated with female sex, aging, BMI ≥ 25 kg/m², SSRI use, alcohol use, and presence of diabetes; there was a trend between lower TBS and history of fragility fractures. TBS may be useful clinically to assess structural changes that may be associated with fractures among patients who are overweight or obese, those on SSRIs, or with diabetes. Ongoing follow-up studies will clarify the effects of supplemental vitamin D₃ and/or FA's on TBS and other bone health measures.

TRIAL REGISTRATION

NCT01747447.

Tracheostomy tube occlusion protocol predicts significant tracheal obstruction to air flow in patients requiring prolonged mechanical ventilation

OBJECTIVE

This study was undertaken to test the hypothesis that a tracheal tube occlusion protocol predicts clinically important obstruction to air flow in patients requiring prolonged mechanical ventilation, making routine bronchoscopy unnecessary.

DESIGN

A prospective evaluation of 75 patients who were clinically ready to be decannulated. All patients underwent the tracheal tube occlusion protocol followed by bronchoscopy.

SETTING

Three hospitals affiliated with a college of medicine.

PATIENTS

Over a 24-month period, 52 males and 23 females were enrolled in the study. Mean age was 55 yrs (range 25 to 85). Mean endotracheal/tracheostomy time was 2.4/8.9 wks (range 1 to 4/5 to 14). All patients were mechanically ventilated for at least 4 wks and were successfully weaned from the mechanical ventilator for at least 48 hrs. During spontaneous breathing, these data were observed: minute ventilation of < 10 L/min; resting respiratory rate of < 18 breaths/min; and arterial oxygen saturation of > 90% on 40% oxygen tracheal collar mask. The tracheal tube occlusion protocol consisted of deflating the cuff on the fenestrated tracheal tube and occluding the tube.

INTERVENTIONS

Patients who developed respiratory distress when the tracheal tube was occluded were deemed to have failed the protocol. At bronchoscopy, the patients were asked to cough and hyperventilate in an attempt to forcibly reduce the cross-sectional area of the trachea. A sustained, subjectively assessed decrease of > or = 50% of the effective cross-sectional area of the trachea was considered to be an indication for intervention.

MEASUREMENTS AND MAIN RESULTS

Sixty-three (84%) of 75 patients tolerated the tracheal tube occlusion protocol. Twelve (16%) of 75 patients developed signs of respiratory distress and showed decreased oxygen saturation values necessitating uncapping of the tracheal tube. All patients had some degree of tracheal injury. However, those patients who failed to tolerate the tracheal tube occlusion protocol had clinically important tracheal obstruction to air flow.

CONCLUSION

A tracheal tube occlusion protocol can predict clinically important obstruction to air flow after prolonged mechanical ventilation.

The FEF25-75% and the clinical diagnosis of asthma

Nonspecific bronchial provocation testing is clinically useful in the evaluation of patients with symptoms suggestive of asthma. Testing is usually reserved for those with normal or near normal baseline spirometry. Although bronchial provocation testing is safe and widely available, the protocol is time consuming and not without expense. It has been reported that a reduced FEF25-75% in the context of an otherwise normal spirogram suggests that asthma should be considered. To evaluate this suggestion, we compared the baseline FEF25-75% (expressed as percent of predicted) with the results of the subsequent methacholine bronchial provocation test in 205 consecutive patients referred for testing. The mean baseline FEF25-75% in the 112 patients with normally responsive airways (ie, a negative bronchial provocation test) was 95.4 +/- 27.5%. In the 93 patients with a positive bronchial provocation test, the mean FEF25-75% was 77.6 +/- 27.2%. The mean FEF25-75% in those with hyperresponsive airways was significantly lower (t = 4.616, P < .0001). Of those patients with a positive bronchial provocation test, there was no significant correlation, however, between the baseline FEF25-75% and the degree of bronchial hyperresponsiveness as assessed by the PC20FEV1 (r = .154, P = .141). When a significant reduction in FEF25-75% was defined as less than 60% of predicted, the sensitivity of the prediction rule was 25.8%, the specificity was 92.0%, the positive predictive value was 72.7%, and the negative predictive value was 60.0%. From these results, we conclude that the FEF25-75% derived from simple spirometry may be useful in predicting the presence or absence, but not the degree, of bronchial hyperresponsiveness.

Environmental tobacco smoke and lung cancer risk in nonsmoking women

BACKGROUND

Exposure to environmental tobacco smoke (passive smoking) has been suggested to be a cause of lung cancer, although early epidemiologic studies have produced inconsistent results.

PURPOSE

We conducted an epidemiologic case-control study to assess the relationship between exposure to environmental tobacco smoke and lung cancer risk among women who have never smoked (i.e., having smoked for a total of less than 6 months or having smoked less than 100 cigarettes in their lifetimes).

METHODS

Case patients (n = 210) were women with histologically confirmed primary carcinomas of the lung who were lifetime nonsmokers. They were identified through hospital tumor registries and the Florida Cancer Data System of the Statewide Cancer Registry. Community-based control women (n = 301) were also lifetime nonsmokers and were identified through random-digit dialing. Details on childhood and adulthood exposures to environmental tobacco smoke were ascertained through interviews with the study participants themselves or with surrogate respondents. Risks were calculated in terms of smoke-years, defined as the sum of the reported years of exposure to cigarette smoke from each smoker in the household.

RESULTS

The risk of lung cancer more than doubled for women who reported 40 or more smoke-years of household exposure during adulthood (odds ratio [OR] = 2.4; 95% confidence interval [CI] = 1.1-5.3) or 22 or more smoke-years of exposure during childhood and adolescence (OR = 2.4; 95% CI = 1.1-5.4). Risks were highest for non-adenocarcinoma lung cancers, although modest elevations in risk were also observed for adenocarcinomas. When a surrogate respondent other than the patient's husband provided information on exposure, the risk estimates were considerably lower.

CONCLUSION

These findings suggest that long-term exposure to environmental tobacco smoke increases the risk of lung cancer in women who have never smoked.

Bronchodilator testing "confidence intervals" based on the level of bronchial responsiveness

"Confidence intervals" based upon inhalation of placebo have been proposed as criteria for defining a significant response to an inhaled bronchodilator. The published intervals were derived from a clinically heterogeneous population. We calculated the difference (delta) between spirometric data before and after placebo in 109 consecutive patients referred for methacholine bronchoprovocation challenge testing. The mean delta, expressed both as a percent change and as actual volume change for both the FVC and FEV1, was not significantly different in patients with bronchial hyperresponsiveness, as compared to subjects with a negative methacholine challenge test; however, the variance of measurements in hyperresponsive subjects was significantly greater than that of the normal population. In addition, as the category of responsiveness increased from mild to moderate to severe hyperresponsiveness, so did the variance within these groups. A negative correlation between the measured PC20FEV1 and the volume and percent change was noted. We conclude that patients with hyperresponsive airways may display increased spirometric variation before and after placebo. This general approach for establishing normal limits for defining a significant response appears to be valid, but the actual values used may vary, depending on the composition of the population tested and the goals of the study. Also, the use of the term, "confidence intervals," in this context is inappropriate; and we propose, instead, the use of percentiles and the simpler terms, upper 90th or 95th percentiles.

Hypervitaminosis A in a cat

A 10-year-old cat that was kept on a diet consisting largely of raw liver was evaluated because of lethargy, partial anorexia, and weight loss of several months' duration. The cat's head and neck were rigidly extended, and a hard mass was palpable in the ventral cervical region. Cervical and thoracic radiography revealed proliferative bony lesions of the cervical and thoracic vertebrae as well as of the sternum and costal cartilages. Serum vitamin A concentration was 4 times normal. For reasons unrelated to hypervitaminosis A, euthanasia and necropsy were performed 6 months after evaluation. The skull and the cervical and first few thoracic vertebrae were rigidly fused, and the vertebral architecture was altered by deposition of new bone. The sternum and costal cartilages were similarly affected. The historical, physical, radiographic, laboratory, and postmortem findings were consistent with the diagnosis of hypervitaminosis A. On the basis of findings in this cat, hypervitaminosis A should be suspected in any sick cat fed a diet consisting partly or completely of raw liver.

Intrapleural streptokinase in management of parapneumonic effusions. Report of series and review of literature

Noncommunicating locules of fluid may develop in the setting of a thoracic empyema or a complicated parapneumonic effusion. When this occurs a single chest tube may not provide adequate drainage. In an effort to promote drainage and thereby obviate the need for further procedures, instillation of streptokinase into the involved pleural space has been advocated. This communication reviews the literature and reports our experience with intrapleural streptokinase. In our retrospective review of nine patients, instillation of streptokinase resulted in an obvious increase in chest tube drainage in six. Of the nine patients, four with improved drainage required no further procedures. Two patients with improved drainage and the three with no change in drainage required an additional chest tube, a decortication procedure, or were lost to follow-up. None of the four patients with an empyema were benefitted. Intrapleural instillation of streptokinase may be a useful adjunct in the treatment of a complicated parapneumonic effusion but appears less likely to be of benefit in the management of an empyema.

Malignant pleural effusions: pleurodesis using a small-bore percutaneous catheter

This study describes our experience using a percutaneously placed small-bore catheter for drainage of malignant pleural effusions and subsequent instillation of a sclerosing agent to obliterate the pleural space. We treated 15 consecutive patients with known metastatic cancer and a symptomatic pleural effusion. Twelve patients survived for more than four weeks after the procedure; 11 of these 12 patients had a successful objective clinical response. The procedure was well tolerated, with little or no discomfort during catheter placement and the maintenance period. No serious complications were encountered. We conclude that the use of a small-bore percutaneously placed "pneumothorax" catheter in the management of malignant pleural effusions is an effective and more comfortable alternative to large-bore closed-tube thoracostomy.

Echocardiography in planned interruption of the inferior vena cava

Interruption of the inferior vena cava by the transvenous placement of a filter or umbrella effectively prevents pulmonary embolism by acting primarily as a physical barrier to emboli. Such a device will be effective only if the site of thrombosis is distal to the planned placement site. We have presented two cases in which a preoperative echocardiogram revealed a right atrial embolus, thereby mandating either embolectomy, fibrinolytic therapy, or continued anticoagulation in addition to the filter placement. These cases suggest that an echocardiogram should be included in the evaluation preceding interruption of the inferior vena cava.

Traumatic urethral avulsion at the preputial fornix in a cat

A cat with pelvic fractures from being hit by a car had voided no urine in 13 hours despite iv administration of fluids. Abdominal radiography had revealed the pelvic fractures and apparently intact urinary bladder. Urine did not flow from a urethral catheter, and contrast radiography revealed the catheter to be extra-urethral within the penis. Intravenous pyelography revealed intact ureters and urinary bladder; celiotomy confirmed intact urinary bladder. Cystotomy and normograde urethral catheterization allowed localization of the ruptured urethra within the deep subcutaneous tissues of the caudal portion of the abdomen. After closure of the cystotomy and celiotomy incisions, perineal urethrostomy was performed.

Clinical use of methacholine bronchial challenge testing

Whereas the research applications have been well established, the clinical utility of bronchial challenge testing is still being defined. In 19 of 22 patients referred for testing (86%), the results of a methacholine challenge test helped to confirm a clinical suspicion of asthma or to suggest that alternative diagnoses should be investigated. There was a discrepancy between the pretest suspicion of the referring physician and the results of the challenge test in six of these 19 patients (32%). Thus our experience suggests that bronchial challenge testing provides useful information to supplement clinical acumen in the diagnosis of asthma.

Pulmonary disease caused by Mycobacterium malmoense

Mycobacterium malmoense was isolated from pulmonary material from 4 patients. Two patients had repeatedly positive smears and cultures along with roentgenographic progression of pulmonary disease in the absence of another pathogen. These 2 patients therefore meet the criteria for diagnosis of pulmonary mycobacteriosis. Isolation of the organism may represent colonization in a third patient, and M. malmoense has been isolated from a fourth patient on 2 occasions. It is not yet definite, however, that the pulmonary process is due to mycobacterial disease. Although uncommon, pulmonary disease caused by this organism has been reported from Europe. Only 1 prior case of pulmonary disease caused by M. malmoense, however, has been reported in the United States.

Oral progesterone treatment in chronic obstructive lung disease: failure of voluntary hyperventilation to predict response

Previous studies have shown that some patients with chronic obstructive lung disease and hypercapnia will respond to medroxyprogesterone with improvement in arterial blood gases. The exact mechanism of this effect is unclear but it is presumed to be a result of ventilatory stimulation. To determine whether the ability to correct arterial blood gas abnormalities by voluntary hyperventilation would predict a subsequent favourable response to progesterone, we studied 11 subjects with chronic obstructive lung disease and chronic hypercapnia. Five subjects had chronic obstructive lung disease of moderate severity with mean (SE) FEV1 1.8 (0.34) 1 maximum voluntary ventilation (MVV) 40.4 (7.16) 1/min-1, arterial oxygen tension (Pao2) 53.8 (2.40 mm Hg, and arterial carbon dioxide tension Paco2) 49.6 (3.91) mm Hg, and were able to normalise their blood gas tensions during voluntary hyperventilation (Pao2 85.4 (8.01) mm Hg; Paco2 32.8 (3.43) mm Hg). Six subjects had severe chronic obstructive lung disease with FEV1 0.77 (0.12) 1, MVV 19 (3.09) 1/min-1, Pao2 60.0 (2.89) mm Hg and Paco2 50.5 (1.38) mm Hg, and they could not significantly alter their blood gases with voluntary hyperventilation (Pao2 62.5 (3.19) mm Hg, Paco2 49.7 (1.84) mm Hg). The groups were similar in age, height, weight, and resting Pao2 and Paco2. Each subject received one month of oral placebo and one month of medroxyprogesterone acetate (Provera). 20 mg orally thrice daily, given in a randomised, double blind fashion. The groups responded similarly with a significantly higher Pao2 and lower Paco2 while having medroxyprogesterone acetate than while having placebo. Two patients with polycythaemia showed a reduction in haemoglobin concentration while taking progesterone. It is concluded that the response to medroxyprogesterone is not predictable from spirometric or blood gas changes after voluntary hyperventilation.

Pulmonary embolism

PE, a common and serious pulmonary problem, most often results as a complication of DVT in the lower extremities. There are no specific symptoms or signs that allow a clinical diagnosis of PE. The best approach to the diagnosis is controversial and is at least partially dependent on the diagnostic capabilities and expertise available at a given hospital. Pulmonary arteriography is the definitive diagnostic test and should be considered in patients with results of less-than-high probability V-Q scans, those at high risk of bleeding complications with anticoagulation therapy, and those considered candidates for thrombolytic therapy.

Bilateral diaphragmatic paralysis complicating local cardiac hypothermia during open heart surgery

Filling the pericardial sac with ice and saline during open heart surgery protects the myocardium during periods of ischemic arrest. Bilateral diaphragmatic paralysis complicated intense local hypothermia in five patients undergoing coronary artery bypass surgery. All complained of severe orthopnea, exertional dyspnea, insomnia, and excessive daytime somnolence. All exhibited paradoxic inward movement of the abdominal wall with inspiration. The diagnosis of bilateral diaphragmatic paralysis was confirmed with upright and supine spirometry and, in one patient, with transdiaphragmatic pressure measurements. Although paralysis has resolved in four patients, all experienced months of disabling impairment. One patient required four months of mechanical ventilatory support prior to her recovery. Alternative methods of intraoperative myocardial preservation that avoid this complication should be developed.

Pulmonary exercise testing

Pulmonary exercise testing can help define the specific cause of exercise-related symptoms. A knowledge of basic respiratory physiology and static pulmonary function studies is necessary to understand and interpret these tests.

Daily spirometric variability: normal subjects and subjects with chronic bronchitis with and without airflow obstruction

To determine the daily variability of spirometry, we performed spirometry on five consecutive days on 15 normal subjects and on 24 patients with chronic bronchitis. The patients with chronic bronchitis were divided into the following two groups: 13 with chronic airflow obstruction (forced expiratory volume in 1 s [FEV1] 80%, FEV1/forced vital capacity [FVC] ratio less than 75%) and 11 without airflow obstruction (FEV1 and FVC greater than 80%0. We attempted to control most of the factors known to affect spirometric variability. Our results indicate that the day-to-day FEV1 has to change by 17% and the FCV by 15% in patients with airflow obstruction before the change should be considered significant. In patients with nonobstructive chronic bronchitis or in normal subjects, a greater than 5% change should occur in FEV1 and FVC before considering the change to be significant.

Cyclic nucleotide phosphodiesterase activity in patients with obstructive airways disease

Cyclic nucleotide phosphodiesterase activity was examined in the pulmonary tissues of patients with no obstructive airways disease, obstructive airways disease responsive to isoproterenol (responders) and obstructive airways disease non-responsive to isoproterenol (non-responders). The phosphodiesterase catalyzed hydrolysis of 0.45 microM levels of adenosine 3',5'-cyclic monophosphate (cAMP) and guanosine 3',5'-cyclic monophosphate (cGMP) was essentially the same in responders as in patients without disease, but was reduced in the non-responders. The results suggest that neither the postulated beta adrenergic receptor-cAMP system defect nor the depressed levels of cAMP reported in patients with bronchodilator-responsive obstruction is caused by an alteration of phosphodiesterase activity.

Reoperation for primary hyperparathyroidism

Between 1960 and April, 1980, 302 patients were explored for primary hyperparathyroidism at Emory University Hospital. Seventeen of these 302 patients had undergone initial surgical exploration elsewhere, and were referred for persistent hypercalcemia. Of the 285 patients who were operated on at our institution, 14 subsequently had persistent hypercalcemia, and two had recurrent hypercalcemia. Twenty-eight of these 33 patients had had re-exploration, and 23 (82%) are now normocalcemic. Twenty-eight abnormal glands were found; 22 (79%) were retrievable via the neck and six (21%) required sternotomy. Of those glands removed via the neck, nine were in a near normal location and 13 in a subnormal or abnormal location. The causes of initial surgical failures were abnormally located glands, in ten patients, insufficient explorations of the neck in eight patients, hyperfunctioning parathyroid remnants in three patients, inadequate plans for hyperplasia in two patients, and carcinoma in one patient. In 57% of our patients who underwent successful re-exploration, the glands were correctly localized before operation by angiographic examination or selective venous sampling for parathormone. Thorough exploration and obtainment of biopsy specimens of all parathyroid glands are recommended in order to keep initial failures to a minimum. If reoperation is required, localization using CT scan, angiography and selective venous sampling are recommended.

The determination of resectability of lung cancer by fiberoptic bronchoscopy

The usefulness of flexible fiberoptic bronchoscopy (FFB) in determining resectability of lung cancer in 152 patients was evaluated. Based on clinical and routine chest roentgenographic examinations, 66 patients (43%) had what were considered to be operable lesions greater than 3 cm in diameter or tumors associated with atelectasis or obstructive pneumonitis (but less than an entire lung), without evidence of pleural effusion or chest wall, mediastinal, or extrathoracic involvement. Forty-eight (73%) of the 66 patients were eventually found to have unresectable conditions. With FFB alone, the conditions of 32 (67%) of these 48 patients were staged as unresectable, so that more invasive procedures, eg, mediastinoscopy or thoracotomy, were required in only 12 and four patients, respectively. Early FFB should be done in potentially resectable cases in which these roentgenographic criteria are met. This procedure is easy, safe, and economical and would allow many patients with lung cancer to have the stage of their disease determined and be treated entirely as outpatients.

Use of lateral position test and perfusion lung scan in predicting mediastinal metastases

The lateral position test (LPT) accurately measures differential ventilation of the lungs when the mediastinum is mobile. The quantitative perfusion lung scan (PLS) also correlates well with differential ventilation but is not dependent on mediastinal movement. If tumor metastasis to mediastinal lymph nodes (MLN) inhibits mediastinal movement, then the PLS may give discordant values for differential ventilation from that of the LPT. Before mediastinoscopy or thoracotomy or both, 14 cases of lung cancer were prospectively evaluated by comparing the relative ventilation of the involved lung as determined by LPT and PLS. Seven patients who had no evidence of MLN involvement had nearly equal ventilation by the two techniques (r = .94), and the absolute difference was always less than 12 percent (mean, 4.4 percent). Seven patients with MLN involvement had unequal ventilation as determined by LPT and PLS (r = 0.07), and between the two techniques there was a difference of at least 13 percent (mean, 27.3 percent). We conclude that the LPT used in combination with the PLS is an accurate, economical, and noninvasive technique for suggesting MLN metastasis and, thus, tentatively staging carcinoma of the lung. Those patients with discordant values should probably undergo mediastinoscopy before thoracotomy.

Bronchodilator effects on gastric acid secretion

Nine patients with chronic obstructive pulmonary disease were given oral aminophylline, intravenous aminophylline, and various inhaled and oral adrenergic bronchodilators to determine the effect of these agents on gastric acid secretion and gastrin release. Inhaled epinephrine hydrochloride resulted in an increase in basal acid output of borderline significance (.05 less than P less than .10). Oral aminophylline caused a significant increase in basal acid output from 2.43 to 4.06 mEq (P less than .05). Intravenous aminophylline also caused a significant increase in basal acid output from 0.66 to 2.19 mEq (P less than .01). There were no statistically significant changes in serum gastrin levels after administration of any of the bronchodilators. Aminophylline should be used with caution, if at all, in patients with peptic ulcer disease. In these patients, a beta agonist should be used for initial therapy. If the addition of aminophylline is necessary, antacids should be given.

Radiographic patterns of drug-induced lung diseases

Drugs which induce lung disease are categorized according to the radiographic pattern of the disease. The five categories are: (a) diffuse interstitial (reticulo-nodular) findings, (b) diffuse air-space consolidation, (c) pleural effusion of fibrosis, (d) hilar or mediastinal widening, and (e) localized areas of consolidation. Information regarding onset, reversibility, fever, eosinophilia, and findings associated with each drug is presented. An extensive list of references is included.

Biopsy of the main carina; staging lung cancer with the fiberoptic bronchoscope

The efficacy of main carinal biopsy through the fiberoptic bronchoscope for evaluating resectability has not been determined. Forty-eight patients with carcinoma, but without gross neoplastic involvement of the main carina, underwent biopsy. Five (10 percent) had abnormal results on biopsy of the main carina. Three of the five patients were initially considered candidates for surgery. There were no complications from the procedure. Biopsy of the main carina through the fiberoptic bronchoscope is a valuable staging procedure in selected patients because of its simplicity and yield and the significance of abnormal findings.

Reduced adenosine 3',5'-cyclic monophosphate levels in patients with reversible obstructive airways disease

1. Patients were grouped into categories of 'no airways disease', 'obstructive airways disease without response to bronchodilator' and 'obstructive airways disease with bronchodilator responsiveness'. 2. Cyclic nucleotides were assayed in specimens of lung tissue that were excised during surgery. 3. Reduced levels of adenosine 3',5'-cyclic monophosphate (cyclic AMP) were found in pulmonary tissue obtained from patients with reversible obstructive airways disease, lending support to the beta-adrenergic theory of asthma.

Toxicity of penicillamine. A serious limitation to therapy in rheumatoid arthritis

A retrospective study of penicillamine toxicity in 156 patients yielded a high incidence of toxic reaction (62%), necessitating discontinuation of the drug therapy in 36% of the patients. Of the total group, proteinuria occurred in 14%, hematologic toxic reaction in 11%, mucocutaneous toxic reaction in 28%, and gastrointestinal intolerance in 12%.

Inhibition of human pulmonary phosphodiesterase activity by therapeutic levels of theophylline

1. To test the hypothesis that inhibition of cyclic nucleotide phosphodiesterase is the major mechanism of the bronchodilator action of theophylline in reversible airways disease, the effects of therapeutic plasma levels of the drug on human pulmonary phosphodiesterase activity were examined. 2. Therapeutic levels of theophylline inhibited the phosphodiesterase-catalysed hydrolysis of adenosine cyclic 3',5'-monophosphate (cAMP) and guanosine cyclic 3',5'-monophosphate (cGMP), but the percentage inhibition was relatively small. 3. The results, while supporting the assumed contribution of phosphodiesterase inhibition to the overall mechanism of theophylline action, suggest that other presently unknown factors must also be taken into consideration to fully explain the beneficial effects of theophylline in reversible airways disease.

Effectiveness of oxygen therapy in hypoxic polycythemic smokers

Eleven hypoxic (arterial oxygen pressure [PaO2] less than or equal to 61 mm Hg), polycythemic (hematocrit reading greater than or equal to 54 percent) patients were studied to determine the effect of the carboxyhemoglobin level on their response to therapy with supplemental oxygen. Five nonsmokers with a mean carboxyhemoglobin level of 2.8 percent showed an excellent response to therapy with supplemental oxygen, with a decrease in hematocrit reading from 57 percent to 48 percent (P less than 0.0025) as the PaO2 increased from 53 mm Hg to 69 mm Hg (P less than 0.01) and the arterial oxygen saturation (SaO2) increased from 86 percent to 94 percent (P less than 0.0025). Six smokers with a mean carboxyhemoglobin level of 13 percent showed an incomplete response to therapy with supplemental oxygen, with a decrease in hematocrit reading from 62 percent to 57 percent (P less than 0.0025) as the PaO2 increased from 53 mm Hg to 69 mm Hg (P less than 0.0025) and the SaO2 increased from 82 percent to 88 percent (P less than 0.001). In spite of similar values for the PaO2, the smokers had higher hematocrit readings before and during therapy with oxygen (P less than 0.01), presumably due to superimposed desaturation by carboxyhemoglobin. We concluded that polycythemia in hypoxic smokers is due to additive effects of hypoxia and a high carboxyhemoglobin level. The former is responsive to therapy with oxygen, while the latter is not. To achieve a "complete" response to therapy with supplemental oxygen, hypoxic polycythemic smokers should quit smoking.

Respiratory abnormalities in hypothyroidism

While the respiratory and oxygen transport systems are complex, they are orderly, so that they can be studied logically and systematically. There are many interactions and potential abnormalities at various levels that may combine to give the ultimate defect of inadequate oxygen supply at the tissue level. An understanding of these many factors using hypothyroidism as a model should enable the clinician to approach the problem rationally and manage if effectively.

Failure of a "prophylactic" antimicrobial drug to prevent sepsis after fiberoptic bronchoscopy

A 53-year-old patient with lymphoblastic lymphoma developed progressive interstitial pulmonary infiltrates. The patient was believed to have Pseudomonas bronchitis and was given parenteral gentamicin. Transbronchial lung biopsy performed through a fiberoptic bronchoscope was complicated by the development of Pseudomonas septicemia. The organism isolated on blood culture, like the one isolated on sputum culture, was fully susceptible to gentamicin in vitro. A prophylactic antimicrobial drug did not prevent bacteremic Pseudomonas infection in our immunosuppressed patient with pre-existent Pseudomonas bronchitis.

Carboxyhemoglobin levels in primary and secondary cigar and pipe smokers

This study of 130 subjects was performed to obtain more data about the smoking habits and levels of carboxyhemoglobin in various types of pipe and cigar smokers. These smokers may be divided by history into primary or secondary smokers and also into current inhalers and noninhalers. Prior studies of carboxyhemoglobin levels have yielded conflicting results, presumably due to differences in current habits of inhalation, which were often not taken into account. Cigarette, primary pipe, and secondary pipe inhalers had similar carboxyhemoglobin levels that were significantly higher than nonsmokers (5.6, 5.0, 5.4, and 1.0 percent, respectively). Cigar inhalers had markedly elevated concentrations of carboxyhemoglobin (13.8 and 11.8 percent in primary and secondary inhalers, respectively). Most secondary cigar and pipe smokers inhaled, whereas most primary smokers did not. Intentional inhalation, rather than past smoking history, is the most important factor in determining the carboxyhemoglobin level for each type of smoke.

Postural hypoxemia in quadriplegic patients

Quadriplegic patients frequently undergo unusual positional changes, including head-down tilt. To determine if hypoxemia develops in this position and whether it is related to the duration of quadriplegia, five patients were studied within 1 year of injury (group A) and five after 1 year from injury (group B). Arterial blood gases were obtained in the seated and 45-degree head-down position. Group A patients had a decrease in arterial partial pressure of oxygen in the head-down position (p less than 0.025), while group B patients did not (p greater than 0.4). This study demonstrated that quadriplegic patients have positional hypoxemia early in their course. This probably results from relative hypoventilation of the upper lung fields caused by flaccid paralysis of the intercostal muscles. The positional hypoxemia disappears with time, presumably because of the change from flaccid to spastic paralysis of the intercostal muscles.

Indications for mediastinoscopy in bronchogenic carcinoma

In an attempt to formulate indications for mediastinoscopy, the histologic tumor type and the radiographic manifestations of the tumor were correlated with the occurrence of mediastinal node metastases in 121 patients who had potentially resectable bronchogenic carcinoma. Our results demonstrated that mediastinal metastases occur commonly in patients with central lesions irrespective of cell type, but that the histologic tumor type has a definite influence on the frequency of mediastinal involvement in patients with parenchymal masses or peripheral lesions. Our results also demonstrated that the absence of radiographic evidence of mediastinal involvement cannot be given strong consideration when selecting patients for mediastinoscopy, because almost 50 per cent of patients with mediastinal involvement did not have mediastinal widening on the chest roentgenogram. Our results, in conjunction with currently accepted principles governing the management of patients with bronchogenic carcinoma, have allowed us to propose a logical approach for the use of mediastinoscopy in the prethoracotomy evaluation of patients with potentially resectable lung cancer.

Cigar inhaling

Carboxyhemoglobin concentrations were compared in 3 groups of outpatients who had inhaled cigarettes in the past. Group 1 consisted of 16 current nonsmokers; group 2, 24 inhaling cigarette smokers; group 3, 10 inhaling cigar smokers. An arterial blood sample was analyzed for carboxyhemoglobin and hemoglobin, and oxygen saturation was calculated and measured. Mean +/- SE carboxyhemoglobin concentrations were 1.0 +/- 0.1, 4.6 +/- 0.5, and 8.4 +/- 1.4 per cent, respectively, for the 3 groups (P less than 0.005). Although calculated oxygen saturation values were not significantly different, measured oxygen saturation values were 96.7 +/- 0.7, 93.0 +/- 1.0, and 88.4 +/- 1.8 per cent, respectively (P less than 0.025). Hemoglobin concentrations in smokers were higher than in nonsmokers (P less than 0.001). This study indicated that cigar smokers who intentionally inhale have higher carboxyhemoglobin concentrations and lower measured oxygen saturation values than cigarette inhalers. This may be even more detrimental to their health than cigarette smoking.

Hyperacute radiation pneumonitis

We present a patient who developed radiation pneumonitis only eight days after beginning therapy. The pneumonitis responded dramatically to prednisone on four occasions, which was a helpful point in the differential diagnosis.