A comparison of high vs standard tidal volumes in ventilator weaning for individuals with sub-acute spinal cord injuries: a site-specific randomized clinical trial.

STUDY DESIGN: Prospective, randomized, controlled parallel group trial with single-blinded data analysis. OBJECTIVES: To determine the safety and efficacy of higher (20 ml kg(-1) ideal body weight (IBW)) vs standard (10 ml kg(-1) IBW) tidal volumes (Vt) for patients with sub-acute traumatic tetraplegia during ventilator weaning using a 14-day (minimum) weaning protocol. SETTING: United States regional spinal cord injury treatment center. METHODS: Thirty-three ventilator requiring inpatients were randomized to either the higher (Group 1) or the standard (Group 2) Vt protocol. Initially, all patients were ventilated at 10 ml kg(-1) IBW Vt and 5 cm H(2)O [corrected] of PEEP for 72 h. For Group 1, Vt was raised 100 ml kg(-1) until reaching target Vt of 20 ml kg(-1) IBW. Group 2 was maintained at Vt of 10 ml kg(-1) IBW. Plateau pressures were kept at or below 30 cm H(2)O. [corrected]. Safety outcomes included incidence of adverse events. RESULTS: Because of smaller than expected enrollment, evaluation of efficacy was not possible. Therefore, we report the safety outcomes of 33 study participants. The 16 patients in Group 1 and 17 patients in Group 2 were demographically similar at baseline, except for age. The average age was 39.3 years in Group 1 and 27.2 years in Group 2, (P=0.002). There was no difference in median days to wean: 14.5 days in Group 1 and 14 days in Group 2. The incidence of adverse pulmonary events was similar between groups. CONCLUSION: Higher tidal volumes can be safely utilized during weaning of patients with tetraplegia from mechanical ventilation using a 14-day weaning protocol.

FDG SPECT in patients with lung masses.

STUDY OBJECTIVES: To determine whether 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG) single-photon emission CT (SPECT) is useful in characterizing pulmonary masses. DESIGN: Scans were prospectively acquired and interpreted. Interpretations were performed with CT or chest radiograph but interpreters were blinded to eventual diagnosis. SETTING: University hospital practice and affiliated Veterans Administration medical center. PATIENTS OR PARTICIPANTS: Forty patients participated as part of an institutional review board-approved research protocol, and informed consent was obtained in all. Eight additional patient scans were acquired as part of their clinical evaluation for pulmonary mass. MEASUREMENTS AND RESULTS: There were 26 malignant lesions (12 were 1 to 2 cm in size, the rest were larger) and 17 benign lesions (3 were < 1 cm in size, 9 were 1 to 2 cm in size, and 5 were larger). Averaged sensitivity, specificity, positive predictive value, and negative predictive value were, respectively, 50% (12 of 24), 94% (17 of 18), 92% (12 of 13), and 59% (17 of 29) for lesions 1 to 2 cm in size, 100% (28 of 28), 90% (9 of 10), 97% (28 of 29), and 100% (9 of 9) for lesions > 2 cm in size. There was good correlation between readers (p < 0.0001). CONCLUSION: FDG SPECT is useful in characterizing pulmonary masses > 2 cm in size and appears to be equivalent to positron emission tomography for these lesions. Although currently clinically suboptimal for characterizing lesions < or = 2 cm in size, FDG SPECT appears to be better than current anatomic imaging methods. In addition, the positive predictive value of FDG SPECT for small lesions is also high (92%), and this technique appears potentially useful in the subset of patients in whom a positive result would alter clinical diagnostic pathways or care.

Sigmoid diverticular perforation complicating lung transplantation.

We present three lung transplant recipients who had sigmoid colonic diverticular perforation within 4 weeks of transplantation, giving an overall incidence of 8.6% (3 of 35) in our population. Our cases are unusual because they all occurred in the early posttransplantation period and because the incidence of perforation is substantially higher than that reported in other transplant populations. The reason for the apparent increased incidence of perforation in our lung transplant recipients is unclear, but it is likely related to the short follow-up period, intense posttransplantation immunosuppression, perioperative hypoperfusion, and increased intraluminal pressure from the use of narcotics and bowel stimulants. We discuss these potential causes and comment on preventive measures being undertaken at our program.

Effect of Proposition 187 on mental health service use in California: a case study.

In this DataWatch we examine whether the passage of California's Proposition 187 affected the use of mental health services in San Francisco County. Using time-series analyses, we identified a 26 percent decrease in the initiation of outpatient mental health services by younger Hispanics at selected service sites after the passage of Proposition 187 in November 1994. Further analyses suggest that decreased use of outpatient mental health services by young Hispanics was associated with their subsequent increased use of crisis services. Other studies of Proposition 187's effect on mental health service use in California are needed to corroborate the findings of this case study.

Clinical evaluation of two fast methods for creatine kinase isoenzyme assay.

Sixty patients admitted to the Cardiac Care Unit were evaluated serially for the presence of CK-MB by electrophoresis and by two comparative fast methods each involving a minimal amount of procedural steps. Immunoinhibition was run manually and by centrifugal analysis. Batch ion-exchange was run in an automated fashion. Correlation among the three methods was good. Further, all three methods displayed excellent accuracy with diagnostic efficiencies ranging from 90% (batch ion-exchange) to 95% (electrophoresis). Utilization of the immunoinhibition reagent on a centrifugal analyzer gave high throughput and reliable results.

Sodium polystyrene sulfonate (kayexalate) aspiration: histologic appearance and infrared microspectrophotometric analysis of two cases.

OBJECTIVE: Sodium polystyrene sulfonate (kayexalate) is a cation-exchange resin given enterally for the treatment of hyperkalemia. Aspiration of this material is a rare occurrence, but when visualized in the alveolus, it has a characteristic microscopic appearance that is virtually diagnostic. In two cases, recognition of the characteristic morphology of the foreign material raised the question of sodium polystyrene sulfonate. DESIGN: We used infrared spectroscopy to demonstrate the presence of this material in lung biopsies of two patients by identifying foreign body particles. Histories of the patients were reviewed for exposure to sodium polystyrene sulfonate. SETTING: Two lung specimens were referred to the Armed Forces Institute of Pathology with an unknown foreign material identified within the air spaces. PATIENTS: The lung biopsies were from two children, one postterm female infant who died at 3 days of life and a 4-year-old girl who underwent lung biopsy during surgical repair for tetralogy of Fallot. Both patients had received sodium polystyrene sulfonate previously for control of hyperkalemia. RESULTS: The lung specimens showed characteristic basophilic, amorphous foreign material in airspaces on histologic sections. The identity of this material was confirmed by Fourier transform infrared microspectrophotometry. CONCLUSIONS: To our knowledge, we report the first two cases of sodium polystyrene sulfonate aspiration in children. This material has a distinctive morphologic appearance on histologic sections, and its identity can be confirmed by Fourier transform infrared microspectrophotometry.

Addition of NaCl to MS-2 system clinical cuvettes for combined salt tolerance and susceptibility testing for group D streptococci.

Sodium chloride was added directly to individual wells of MS-2 system clinical cuvettes for evaluating the feasibility of simultaneous susceptibility and salt tolerance testing for group D streptococcal isolates. Salt tolerance was correctly detected for all 177 enterococci tested; there was no false-positive results for 29 group D nonenterococcal or 45 viridans streptococcal isolates.

Calcium fractions in serum of patients with thermal burns.

Total calcium measurement is less useful clinically than assay of the physiologically active fractions, free and ionized calcium. The latter were measured in burned patients by ultrafiltration and by ion-selective electrode. Hypocalcemia was observed in these patients but it was generally limited to low total calcium. On average, free or ionized calcium were in the normal range. Total and free calcium were weakly correlated with severity of burn injury suggesting a loss of several forms of calcium in severe burn injury. An algorithm was derived to allow calculation of free calcium from total calcium and albumin. Interpatient variables are important, however, so that the algorithm should not be substituted for actual assay of free and ionized calcium.

Production of volatile nitrogenous compounds from the degradation of streptomycin by Pseudomonas maltophilia.

Ammonia, methylamine, and pyridine were detected in broth filtrates of a streptomycin-degrading strain of Pseudomonas maltophilia during growth on streptomycin as a sole carbon and nitrogen source. Ammonia and methylamine, quantitatively measured by conversion to chromophores with picryl sulfonic acid, were found to accumulate in broth, whereas pyridine concentration increased in the early stages of streptomycin degradation and then decreased as the degradation of the antibiotic neared completion. Exogenous pyridine was metabolized by washed-cell suspensions. Use of N-streptomycin-methyl-(14)C showed that the methylamine arose from the N-l-glucosamine-methyl moiety of streptomycin. Methylamine was an end product and was not further metabolized by cells.

Diagnostic efficacy of a new enzyme immunoassay for creatine kinase MB isoenzyme.

A new commercial enzyme immunoassay kit for quantification of creatine kinase-MB (CK-MB) isoenzyme was compared with its electrophoretic determination with respect to efficacy in diagnosis of acute myocardial infarction. Enzygnost CK-MB (Behring Diagnostics) is a solid-phase "sandwich"-type enzyme immunoassay with antibodies to the B-subunit coated on plastic tubes and peroxidase-conjugated antibodies to the M-subunit added after incubation with sample. This kit is designed to measure only CK-MB and not CK-MM, CK-BB, adenylate kinase, or atypical CK molecules. The linear-regression equation comparing the two methods was: Enzygnost = 0.98 . electrophoresis - 0.72, with a correlation coefficient of r = 0.967 (n = 143). For 51 patients admitted for diagnosis of possible acute myocardial infarction, the Enzygnost kit achieved 100% sensitivity, specificity, and efficiency in predicting the correct diagnosis. Corresponding values for the electrophoretic assay were: 95.5% sensitivity, 93.1% specificity, and 94.1% efficiency. We conclude that this kit method provides an excellent alternative to electrophoresis.

Effect of California's proposition 187 on the use of primary care clinics.

California's ballot proposition 187, passed by the voters in November 1994, threatened to discontinue undocumented immigrants' eligibility for most health services while mandating that health care professionals report suspected undocumented patients to authorities. Although the proposition has not been put into practice, reports suggest that its passage was associated with a decline in the use of health services by some groups. To assess the effects of the passage of Proposition 187 on the use of primary care services, we surveyed a representative sample of California clinics serving low-income groups (n = 129). Using a mailed questionnaire and phone interviews with clinic directors, we obtained qualitative and quantitative data regarding the effects of the passage of the proposition on clinic use. Among primary care clinics statewide and clinics serving predominantly Latino patients, we detected no significant decline in total monthly visits following the election. Nevertheless, half of clinic directors (51%) thought that the number of clinic visits declined after the passage of Proposition 187, and many directors thought that the deterrent effects of the election persisted for weeks to months after the election. Whereas the number of visits probably declined at some clinics, only a small minority of patients at most primary care clinics could have been deterred from seeking care after the passage of Proposition 187.