Oxygen tubing lengths and output flows: implications for patient care.

BACKGROUND: Historical wisdom has recommended up to 50 ft (15.24 m) of tubing based on the oxygen cylinder delivery system. Yet, many individuals may store their stationary systems in one area of the home and conduct their activities at distances by adding additional tubing. The aim of this study was to discriminate at what lengths clinically relevant decreases in flow greater than 20% occurred. METHODS: Plastic tubing was added at 25 ft (7.62 m) intervals connected via a swivel adapter up to 200 ft (60.96 m) to a cylinder, concentrator and liquid stationary oxygen system to simulate a home oxygen environment. Flows of 1-5 L/min were set then measured via the Timemeter 200 after each segment of additional tubing. RESULTS: Output from the cylinder with regulator/flowmeter was greatly diminished as tubing and flowrate was increased which resulted in clinically significant reductions in flow at 2 L/min for tubing lengths greater than 100 ft (30.48 m). The oxygen concentrator had little flow reduction at 1 or 2 L and more flow loss at higher tubing lengths with 3, 4 and 5 L/min. Liquid oxygen was only mildly reduced at 125 ft (38.10 m) of tubing and 4 or 5 L of flow. Neither the concentrator nor liquid oxygen delivery units had flow reductions greater than 13.5 and 4.0%, respectively, at 2 L/min with 200 ft (60.96 m) of tubing. SUMMARY AND RECOMMENDATIONS: Tubing length up to 200 ft (60.96 m) could be utilized for providing patient home oxygen with Puritan Bennett style liquid oxygen. We recommend consideration of tubing lengths up to 200 ft (60.96 m) and up to 3 L/min or 100 ft (30.48 m) at 4-5 L/min for Invacare 5 and similar oxygen concentrators; however flow delivery should be verified by the manufacturer. The cylinder regulator/flowmeter system suffered the greatest flow loss. Flows of 1-2 L/min can be clinically maintained with up to 100-ft (30.48 m) of tubing. This study brings clarity of when tubing can be lengthened which may enhance movement within the home and lessen constraints.

Marathon with cystic fibrosis and bilateral lung transplant.

The article presents studies performed before, during and after a marathon run (42,195 m) in a 32-year-old man who underwent a bilateral lung transplantation because of end-stage cystic fibrosis (CF) 15 months prior to the race. Before the run his FEV1 was 81% predicted, compared with 19% predicted before the operation, and his maximal oxygen uptake was 31.9 ml/kg(-1)/min(-1). He completed the New York City Marathon 1998 without major problems in 7 h 8 min 50s. Pulmonary tests, biochemical changes and endocrine responses indicated transient changes, mostly as expected in healthy marathon runners. The case demonstrates that physiological trainability and psychological will power following a successful bilateral lung transplantation can transform a chronically ill CF patient into a robust marathon runner.

Abdominal organ segmentation using texture transforms and a Hopfield neural network.

Abdominal organ segmentation is highly desirable but difficult, due to large differences between patients and to overlapping grey-scale values of the various tissue types. The first step in automating this process is to cluster together the pixels within each organ or tissue type. We propose to form images based on second-order statistical texture transforms (Haralick transforms) of a CT or MRI scan. The original scan plus the suite of texture transforms are then input into a Hopfield neural network (HNN). The network is constructed to solve an optimization problem, where the best solution is the minima of a Lyapunov energy function. On a sample abdominal CT scan, this process successfully clustered 79-100% of the pixels of seven abdominal organs. It is envisioned that this is the first step to automate segmentation. Active contouring (e.g., SNAKE's) or a back-propagation neural network can then be used to assign names to the clusters and fill in the incorrectly clustered pixels.

Evaluation of a multicrystal gamma camera and rotating chair for tomographic studies of the heart.

BACKGROUND: This study evaluates the feasibility of performing tomographic studies with a multicrystal gamma camera combined with a rotating chair. METHODS AND RESULTS: Tomographic acquisitions were performed with a cardiac phantom containing eight defects of different sizes. Defect size was determined from the fraction of counts in the short-axis slices that fell below a fixed threshold value. Image contrast was determined from the ratio of minimum/maximum counts. Images of an American College of Nuclear Physicians cardiac single-photon emission computed tomographic phantom were acquired and the results were compared with those obtained from 194 centers in the United States. For cardiac studies with 201Tl and 99mTc, threshold values of 65% to 70% gave the best correlation (R2 > 0.94) between true and measured defect sizes, although the slope of the regression line was less than 0.95 for both isotopes. Small inferior defects demonstrated poor image contrast, particularly for 99mTc. Of the three defects in the American College of Nuclear Physicians phantom, the two largest were identified in the tomographic images. CONCLUSIONS: A multicrystal gamma camera system coupled with a rotating chair can be used for tomographic studies of the heart. Image quality is poorer than that seen on conventional single-photon emission computed tomographic systems, particularly for 99mTc.

Detection by immunoblot assay of antibodies to Taenia solium cysticerci in sera from residents of rural communities and from epileptic patients in Bali, Indonesia.

Several studies from Bali have indicated the presence of Taenia solium. Relatively little has been reported, however, implicating human exposure to this parasite on Bali based upon the prevalence of anti-T. solium antibodies in asymptomatic and epileptic individuals. This study was conducted to determine by immunoblot assay and ELISA the frequency of anti-cysticercus antibodies in two groups of Balinese. Among 746 residents of four ecologic zones, 94 (13%) were positive by immunoblot. Of 74 epileptic patients from throughout the island, 10 (14%) were positive by immunoblot and 8 (11%) by ELISA; however, only 4 (22%) of the 18 sera positive in either test were positive in both assays. The previously defined high specificity and sensitivity of immunoblot indicates that T. solium cysticercosis is well established in Bali and that a significant amount of epilepsy may be due to neurocysticercosis.

Serosurvey of some major zoonotic infections in children and teenagers in Bali, Indonesia.

One hundred and ninety serum samples, mainly from children and teenagers, from northeast Bali were tested for the presence of antibodies against five zoonotic agents: Brucella abortus, Coxiella burnetii, Toxoplasma gondii, Toxocara canis and Trichinella spiralis. All children were negative for brucellosis and Q fever. A high prevalence rate was found for toxocariasis (63.2%) and trichinosis (19.5%). Antibody prevalence against T. gondii was found to be rather low (3.1%). To our knowledge, this is the first evidence of toxoplasmosis, toxocariasis and trichinosis infection in humans on Bali. Eating habits and poor hygiene may explain the frequency of parasitic infestations in the children and teenagers in Bali.

Prognostic significance from 10-year follow-up of a qualitatively normal planar exercise thallium test in suspected coronary artery disease.

A normal exercise thallium-201 scintigram has been shown to confer an excellent prognosis over a 1- to 4-year follow-up period. However, progression of coronary disease could result in cardiovascular mortality with increasing time. Therefore, the vital status of 309 patients with normal stress thallium myocardial imaging was determined after an average of 10.3 years. Deaths were classified as cardiac or noncardiac. Statistical analysis was performed using Kaplan-Meier survival curves. Standardized mortality ratios were calculated and compared with those of an age- and sex-matched general population. Follow-up was complete in 288 patients (93%). Of 18 deaths, only 3 were cardiac; the remaining 15 were mainly secondary to cancer. Thus, cardiac mortality was 1% and total mortality 6.3% at 10 years. In addition, both all-cause and cardiac mortality rates were significantly less than would be expected in an age- and sex-adjusted segment of the general population. Thus, normal exercise thallium scintigraphy retains its high negative predictive value for death < or = 10 years after initial testing. This supports the use of stress thallium imaging to predict which patients with suspected coronary artery disease are at low risk for cardiac death and thus do not need invasive testing.

Bypass surgery for chronic stable angina: predictors of survival benefit and strategy for patient selection.

The variable mortality risk associated with chronic stable angina calls for careful selection of patients for coronary artery bypass grafting (CABG) if the aim of management is to prolong life. The randomized and observational studies done in the last 20 years have identified the variables relevant to patient selection and thus have provided a rational basis for such clinical decisions. These studies showed that the sicker the patient, as gauged by relevant measures of coronary disease and cardiovascular morbidity, the more likely it is that CABG will prolong life. A CABG-related improvement in survival is therefore more likely to occur the worse the left ventricular function; the greater the number of diseased vessels; the more proximal the location of coronary lesions (more muscle is threatened by such lesions); the greater the severity of the lesions as determined by angiography; the more severe the angina; the more easily provocable the ischemia or the more extreme the measures of ischemia; and, within limits, the older the patient. Greater survival gain after CABG also occurs in patients with peripheral vascular disease, in patients with baseline electrocardiographic ST-segment and T-wave changes, and probably in women. Thus, patients are likely to live longer after CABG if they have left main disease; three-vessel disease with left ventricular dysfunction (ejection fraction less than 50%), class III or IV angina, provocable ischemia, or disease in the proximal left anterior descending coronary artery; two-vessel disease with proximal left anterior descending artery involvement; and two-vessel disease with class III or IV angina as well as either severe left ventricular dysfunction alone or moderate left ventricular dysfunction together with at least one proximal lesion. When the decision of whether to do CABG is less clear-cut, the presence of peripheral vascular disease, female sex, baseline electrocardiographic ST-segment and T-wave changes, or older age (over 60 but under 80 years) should weigh in favor of doing CABG. In general, patients with single-vessel disease do not seem to derive survival benefit from CABG.

Lomefloxacin, a new difluoroquinolone: in vitro activity against gram-positive and gram-negative bacteria.

The in vitro activity of lomefloxacin, a new difluoro-quinolone, was compared to other antimicrobial agents against a selection of Gram-positive and Gram-negative organisms. Against the Enterobacteriaceae, the lomefloxacin MIC inhibiting 90% of strains was less than or equal to 0.5 micrograms/ml. Ninety per cent of Pseudomonas aeruginosa and Acinetobacter sp. isolates were inhibited at less than or equal to 4 micrograms/ml. All staphylococci including methicillin-resistant organisms were susceptible at 1.0 micrograms/ml. Enterococcus faecalis, Listeria spp., and sero Group B streptococci were more resistant with an MIC90 of 8, 16 and 4 micrograms/ml, respectively.

Role of exercise thallium-201 myocardial perfusion scintigraphy in predicting prognosis in suspected coronary artery disease.

While exercise thallium imaging has improved sensitivity and specificity for detection of coronary artery disease (CAD), its predictive value for morbid cardiac events is unclear. Of 532 consecutive patients who underwent exercise thallium imaging, follow-up was complete in 515 (97%) after an average of 36 months (range 31 to 48). Two hundred six patients had an abnormal exercise thallium response and 309 had a normal response. Twenty morbid cardiac events occurred (13 deaths and 7 acute myocardial infarctions [AMI]). Of the 13 patients who died, 12 had abnormal thallium results. Overall, 5.8% of the patients with abnormal thallium results died, in contrast to 0.3% of patients with normal results. Of the 7 patients who had a nonfatal AMI, 3 had abnormal exercise thallium results. Moreover, similar proportions of patients (1.4% and 1.3%) with normal and abnormal exercise thallium results had nonfatal AMI. Presence or absence of pathologic Q waves and inclusion of exercise electrocardiographic results did not significantly alter the results. Thus, although a normal exercise thallium response significantly reduces the likelihood of cardiovascular death, its predictive value for nonfatal AMI is limited. Moreover, the relatively low event rate for patients with a positive exercise thallium response further limits its prognostic value.

Expectations and outcomes for patients given mental health care or spiritist healing in Puerto Rico.

In Puerto Rico, spiritism offers a traditional alternative to community mental health services. The author compares reported expectations and outcomes of mental health center patients and patients of spiritist healers. The spiritists' patients reported significantly higher expectations, especially for mood and feeling complaints. Both patient groups had a similar duration and severity of symptoms. The outcome ratings of spiritists' patients were significantly better than those of therapists', but this difference could be accounted for by the higher expectations of the spiritists' patients. With these exceptions, the findings do not account for the selection of one type of treatment over the other.