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STUDY OBJECTIVE: To examine the safety and efficacy, as well as the economic impact, of outpatient intravenous antibiotic administration using an ambulatory infusion pump. DESIGN: Retrospective analysis of patients treated through a single home care pharmacy. SETTING: General community and skilled nursing facilities of the greater Monterey (California) area. PATIENTS: Ninety-eight consecutive patients with infections requiring parenteral antibiotics, treated outside the acute-care setting and not eligible for traditional intravenous minibag administration. INTERVENTIONS: Patients received intravenous antibiotics either in the home setting (86%) or in skilled nursing facilities (11%) using a Pharmacia Deltec CADD-VT ambulatory infusion device. MEASUREMENTS AND MAIN RESULTS: Between April 1, 1986, and July 30, 1988, 98 patients received parenteral antibiotics using an infusion pump, and complete data were available on 96 (98%). A total of 109 treatment courses were given over 1,917 treatment days, with a mean duration of therapy of 18 days. Twenty-three different infections were treated by the use of 12 separate antibiotics. The most common complications included vein irritation (11%) and the inability to maintain venous access (6.2%). Therapy costs were equivalent to or less than the intravenous minibag system depending on the frequency of antibiotic administration. Eighty percent of patients experienced successful resolution of their infection. CONCLUSIONS: Ambulatory antibiotic infusion pumps can be used safely and effectively in the outpatient setting. Use of these pumps should increase the number of patients eligible for out-of-hospital treatment, resulting in a marked reduction in treatment costs.

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Aerosol inhalation lung scans offer distinct advantages in the evaluation of airways and the qualitative distribution of ventilation. The sensitivity in detecting mild obstructive disease is similar to that of xenon washout and both probably surpass standard pulmonary function tests that measure total rather than regional ventilation. Although imaging studies using krypton gas are ideal for assessment of rapidly ventilated space, krypton's short half-life precludes its usefulness for demonstrating air trapping. Neither 133Xe nor 81mKr gas demonstrates sites of airway abnormality as aerosol does. Aerosols are ideal for the general nuclear medicine practice in community hospitals because of their convenience, cost effectiveness, and information yield. Current technique using same-day multiple-view aerosol scans after a preliminary perfusion scan, makes use of the most logical diagnostic scheme in the vast majority of patients with chest complaints, since a normal perfusion scan often eliminates the need for a ventilation scan.

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In 12 asthmatic subjects with mild to severe airways obstruction, we compared the relative magnitude and sites of airway dilatation of a beta-adrenergic stimulant administered by different routes. Specific airway conductance (SGaw), peak expiratory flow, the sum of the absolute volume of isoflow and residual volume as a percentage of total lung capacity (capacity of isoflow) and the ratio of maximal expiratory flow at 50 per cent of vital capacity breathing 80 per cent helium-20 per cent oxygen to that breathing air (ratio Vmax50) were determined before and after the administration of aerosolized terbutaline (0.5 mg), subcutaneous terbutaline (0.5 mg) or placebo. Increases in SGaw and peak expiratory flow of greater than or equal to 25 per cent were considered to indicate significant dilatation of central airways; increases in ratio Vmax50 of greater than or equal to 0.10 and decreases in capacity of isoflow of greater than or equal to 10 per cent were assumed to reflect dilatation of peripheral airways. In addition, radioaerosol and radioxenon lung imaging was performed to determine the relationship between changes in lung imaging patterns and changes in physiologic indices in response to bronchodilator therapy. Placebo caused little change in lung function or lung imaging. After inhaled terbutaline, SGaw and peak expiratory flow increased greater than or equal to 25 per cent in seven subjects, ratio Vmax50 increased greater than or equal to 0.10 in only three subjects, capacity of isoflow decreased greater than or equal to 10 per cent in only one subject, radioaerosol images showed less central deposition in nine subjects and radioxenon images showed improved distribution and/or washout of xenon in five subjects. After the administration of subcutaneous terbutaline, SGaw and peak expiratory flow increased greater than or equal to 25 per cent in 10 subjects, ratio Vmax50 increased greater than or equal to 0.10 in 10 subjects, capacity of isoflow decreased greater than or equal to 10 per cent in 11 subjects, and radioaerosol and xenon images showed improvement in 11 and eight subjects, respectively. These findings are consistent with the action of inhaled terbutaline mainly on large airways and of subcutaneous terbutaline on both large and small airways. Although reduced central radioaerosol deposition correlated well with physiologic evidence of large airway dilatation, improvement in xenon distribution and washout could be attributed to dilatation of either large and/or small airways.

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Solutions of 99mTc-diethylenetriaminepenta-acetate (99mTc-DTPA) and 99mTcO-4 were aerosolized and inhaled by subjects seated against a scintillation camera. Initial clearance rates of these radionuclides were determined over 6 posterior lung regions. Clearance of 99mTcO-4 (molecular weight, 163 dalton exceeded that of 99mTc-DTPA (molecular weight, 492 daltons) by an average factor of 3.3. Upper-lobe clearance of both radionuclides was greater than lower-lobe clearance in the normal subjects, but this gradient was abolished when the subjects exhaled against 7 cm of positive end-expiratory pressure. Twenty-one patients with clinical and roentgenographic evidence of interstitial lung disease (ILD) and diminished CO diffusion rates were studied with 99mTc-DTPA. Clearance of 99mTc-DTPA was increased in each of 5 patients with idiopathic pulmonary fibrosis, 4 of 8 with sarcoid, 2 of 5 with pneumoconiosis, and 2 of 3 patients with other forms of ILD. In contrast, the clearance of 99mTcO-4 was decreased in 4 patients with pulmonary alveolar proteinosis. Furthermore, no increase in 99mTc-DTPA clearance was found in 5 patients with chronic obstructive pulmonary disease. These studies suggest that the initial clearance of these aerosolized hydrophilic radionuclides is accomplished in part by diffusion through the epithelium of alveoli and respiratory bronchioles. Whereas radionuclide clearance is impaired by the presence of precipitated protein in these structures in pulmonary alveolar proteinosis, clearance is accelerated in ILD. This may indicate increased epithelial permeability in ILD related to injury and increased retractile forces.

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The sites of airway obstruction and dilatation after terbutaline administration were studied by inhalation imaging and pulmonary function tests in 12 stable asthmatic patients. Inhaled terbutaline as a therapeutic aerosol decreased airway resistance (Raw) and improved radioaerosol (Ae) images in nine, delta V max50 in three, and xenon (Xe) images in five of 12 subjects, suggesting that its predominant site of action was on major airways. Subcutaneously injected terbutaline improved Raw, delta V max50, and Ae images in 11 and Xe images in eight subjects indicating that it released bronchospasm in the major and minor airways. These findings in asthma suggest that aerosol and Xe imaging procedures are sensitive indicators of large and small airway obstruction respectively.

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An improved radioaerosol administration system has been developed to reduce the number of droplets larger than 2.0 micron in diameter which have caused abnormal hyperdeposition of inhaled aerosols in the large airways. The new system has achieved this goal by interposing a reservoir-setting bag in the aerosol delivery line between the nebulizer and the patient. The components are inexpensive, commercially available and easily assembled in any nuclear medicine service.

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We have described a patient with paralysis of the diaphragm, in whom dyspnea, hypoxemia, and hypercapnia increased when he changed from the upright to the supine position. Ventilation (V) and perfusion (P) images of the right lung appeared to be normal and remained nearly the same in the upright and supine positions. In contrast, V and P images of the left lung were smaller than those of the right lung in the upright position and decreased further in the supine position. In addition, the ventilation image of the left lung was much smaller than the perfusion image in both positions.

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Clearance rates of soluble radioaerosols of sodium pertechnetate (99mTcO4; mol wt 163) and diethylenetriaminepenta-acetate (99mTc-DTPA; mol wt 492) were determined in seven normal subjects and ten patients with systemic sclerosis affecting the lungs. Twenty millicuries (mCi) each of 99mTcO4 and 99mTc-DTPA in 5 ml saline were aerosolised and inhaled using a disposable "Blount" nebuliser on two different days. Two regions of interest over each posterior lung field were monitored with scintillation camera, and data were stored on magnetic tape using a Hewlett Packard Data Analyser. Decreasing levels of radioactivity were plotted semilogarithmically and half-time (T 1 1/2) removal rates were calculated. The T 1 1/2) values in normal subjects did not differ significantly from T 142 values of the patients with TcO4. However, the removal rates of the higher molecular weight solute were significantly faster from lower lung zones in patients with systemic sclerosis than in the normal subjects. The faster absorption of DTPA from lower lung zones of the patients could be due to regional abnormalities of alveolar epithelium at the lung bases, presumably as a result of greater retractive forces secondary to fibrosis.

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Krypton lung-imaging is considered the ventilation procedure of choice when it is available. Aerosol and krypton wash-in images both reveal regional abnormalities of ventilation, but the aerosol images also disclose evidence of major airways disease. Xenon wash-out images are probably the most sensitive indicators of regional abnormalities of ventilation and/or small airways obstruction, whereas xenon wash-in images are far less sensitive and may be frequently misinterpreted. The Tc-DTPA aerosol inhalation procedure is perferred over xenon and krypton ventilation imaging for routine use immediately after a perfusion examination in pulmonary embolism suspects. This combined method provides the referring physician with the necessary diagnostic information quickly and with around-the-clock availability. In our opinion, this new aerosol procedure deserves wider application in the diagnosis and management of pulmonary disease. Lung imaging procedures, performed after th inhalation of 99mTechnetium labeled aerosols, 133Xenon and and 81mKrypton gases, were used to visualize the sites of airway obstruction and regional abnormalities of ventilatory function in normal volunteers, patients with obstructive airway disease and pulmonary embolism suspects. This chapter presents intercomparisons of these three methods regarding their functional significance, diagnostic merits, and limitations. A new nebulizer-radioaerosol delivery system is described. Test agent kits are inexpensive and readily available for on site assembly. Currently, we consider radioaerosol imaging in multiple views as more informative and suitable for routine use than xenon methods to detect regional abnormalities of the airways and ventilatory function. The krypton procedure is preferred in pulmonary embolism suspects because it requires far less patient cooperation than the xenon and aerosol methods and the lung images disclose regional ventilatory impairment quickly and accurately. However, krypton gas is cyclotron-produced and not yet commercially available.

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A new tracer method for quantitative measurement of tracheal transport velocity (mm per min) in dogs has been described. Using the same technique, the effects of dehydration, rehydration, postural drainage, and chest percussion on tracheal transport velocity were studied. Mean tracheal transport velocity decreased significantly (14.1 +/- 1.4) after dehydration (P less than 0.05) and reverted to normal (19.0 +/- 1.3) with rehydration in 10 dogs. After postural drainage in 7 dogs, mean tracheal transport velocity increased 39.7 +/- 1.78 (SE) per cent (P less than 0.01). After chest percussion in 6 dogs, mean tracheal transport velocity increased 50.9 +/- 1.22 (SE) per cent. With combined postural drainage and chest percussion, mean tracheal transport velocity increased 50.0 +/- 0.32 (SE) per cent. Although maximal improvement occurred after the combined therapy, the changes were not significantly different from those observed with each therapy alone. These therapeutic measures have been used empirically in the past. The present study gives some objective evidence for their beneficial effects in anesthetized dogs.

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One hundred subjects answered a respiratory questionnaire and underwent a physical examination, tests of pulmonary function, and three radionuclide lung-imaging procedures. The results of the radionuclide procedures were compared with each other and with pulmonary function tests and other diagnostic findings to determine their relative sensitivity for detecting evidence of early obstructive airway disease. Perfusion lung imaging was less sensitive than most of the other diagnostic tests evaluated. The aerosol and xenon lung-imaging procedures revealed abnormalities with approximately the same frequency as each other, but more often than any one group of pulmonary function tests, including spirometric data, maximal expiratory flow-volume curves, alveolararterial oxygen gradient, or indices derived from single-breath nitrogen washout. We concluded that xenon and aerosol lung-imaging studies are sensitive and useful screening procedures for detecting evidence of early localized obstructive airway disease and for locating regional abnormalities in the airways of patients with respiratory disease.

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Regional lung ischemia was imaged with a rapidly diffusible radioaerosol of pertechnetate. The method is compared with similar techniques using 11C and 15O. The principles involved include (A) the rapid alveolar-capillary diffusion of inhaled radioactive gases (11CO, C15O, and C15O2) and the radioaerosol of 99mTcO4-; (B) the patency of the airways to the ischemic regions; and, most importantly; (C) the much slower tracer removal from lung tissue with a stagnant circulation as opposed to the surrounding normal lung. The 11CO and C15O label the hemoglobin in red blood cells, and the C15O2 labels water in the circulation and in the stagnant ischemic region. The TcO4- probably labels the albumin of the plasma in the embolized regions and in the circulating blood. Experiments involving pulmonary embolism in dogs, proved by pre- and post-mortem angiography and gross post-mortem examination, show that positive ischemic lesions (hot spots) are observed, after TcO4- aerosol and C15O2 gas inhalation, in the embolized region on the same day. Clinical trials with aerosol-inhalation method in suspected pulmonary embolism and now under way.

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A new method for measuring the velocity of the tracheal mucous transport rate in anesthetized dogs is described. The length of the trachea is determined with the bronchoscope as the distance between the larynx and the lower end of the trachea at the level of the carina. A small volume (0.04 to 0.1 ml) of albumin microspheres 5 mgm to 7 mum in diameter labeled with radioactive 99m technetium or 113m indium is deposited on the mucosal surface at the lower end of the trachea via a catheter placed in the inner channel of a fiberoptic bronchoscope. The movement of the microspheres towards the larynx is visualized and recorded using a scintallation camera (Picker Dyna Camera) with a large field of view (30 cm in diameter) for 30 to 60 minutes, depending upon the time required for the spheres to reach the top of the trachea. Polaroid pictures are made immediately and every minute thereafter until the activity reaches the larynx. The data are also recorded and stored on magnetic tape for subsequent analyses by computer. The length in millimeters divided by the time in minutes gives the transport velocity rate. The mean velocity was found to be 19.2 +/- 1.6 mm/min (+/- SE).

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Dynamic lung circulation scintigraphy employing intravenously administered 99mTc as pertechnetate was used to visualize the pulmonary arterial and systemic arterial circulations in a patient with bronchogenic carcinoma. Computer-processed dynamic images and region-of-interest data were utilized to demonstrate differences between tumor and normal regions regarding pulmonary and systemic blood supplies.

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A new method is described for imaging small ischemic regions in the lung immediately after a single breath of radioactive carbon monoxide (11CO). A tungsten-collimated scintillation camera is used to visualize the 0.51-MeV annihilation photons due to the 11C. In normal dogs the entire field is cleared of 11CO within 10 sec. However, in dogs with experimentally occluded 2-mm-diam segmental arteries, the ischemic but well-ventilated segment appears as a region of persistent high radioactivity, due most likely to temporary entrapment of 11CO-labeled red blood cells in the ischemic region. This technique also provides a simple noninvasive means for instantly labeling the systemic circulation without left heart catheterization.

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