Guy W. Soo Hoo

OBJECTIVES: To evaluate the efficacy of nasal mechanical ventilation in patients with chronic obstructive pulmonary disease and hypercapnic respiratory failure and to identify predictors of success or failure of nasal mechanical ventilation. DESIGN: Prospective case series. SETTING: Medical intensive care unit in Veterans Administration Medical Center. PATIENTS: Twelve chronic obstructive pulmonary disease patients treated during 14 episodes of hypercapnic respiratory failure. INTERVENTIONS: Nasal mechanical ventilation in addition to conventional therapy to treat hypercapnic respiratory failure. Patients underwent nasal mechanical ventilation for at least 30 mins, or longer if the therapy was tolerated. Responses to therapy and arterial blood gases were monitored. MEASUREMENTS AND MAIN RESULTS: Half of the episodes were successfully treated with nasal mechanical ventilation. There were no differences in age, prior pulmonary function, baseline arterial blood gases, admission arterial blood gases, or respiratory rate between those patients successfully treated and those patients who failed nasal mechanical ventilation. Unsuccessfully treated patients appeared to have a greater severity of illness than successfully treated patients, as indicated by a higher Acute Physiology and Chronic Health Evaluation II score (mean 21 +/- 4 [SD] vs. 15 +/- 4; p = .02). Unsuccessfully treated patients were edentulous, had pneumonia or excess secretions, and had pursed-lip breathing, factors that prevented adequate mouth seal and contributed to greater mouth leaks than in successfully treated patients (the mean volume of the mouth leak was 314 +/- 107 vs. 100 +/- 70 mL; p < .01). Successfully treated patients were able to adapt more rapidly to the nasal mask and ventilator, with greater and more rapid reduction in PaCO2, correction of pH, and reduction in respiratory rate. CONCLUSIONS: Patients who failed nasal mechanical ventilation appeared to have a greater severity of illness; they were unable to minimize the amount of mouth leak (because of lack of teeth, secretions, or breathing pattern) and were unable to coordinate with the ventilator. These features may allow identification of poor candidates for nasal mechanical ventilation, avoiding unnecessary delays in endotracheal intubation and mechanical ventilation.

Animal-to-human transmission of drug-resistant salmonella and the role of antimicrobial use in food animals in the emergence of these bacteria are controversial subjects. Investigation of a 4.9-fold increase in Salmonella newport isolations from Californians in 1985 showed that 87 percent of the isolates had an unusual antimicrobial-resistance pattern (including chloramphenicol resistance) and a single, identical plasmid. Interviews of 45 patients and 89 matched controls in Los Angeles County showed that illness was associated with penicillin or tetracycline use during the month before onset (P less than 0.001) and with eating ground beef during the week before onset (P = 0.052). The epidemic strain was isolated from hamburger products eaten by cases, abattoirs where the animals from which the meat came were slaughtered, dairies that sent cows for slaughter on days when culture-positive products were processed, and ill dairy cows. Isolation of salmonella from beef carcasses in abattoirs correlated with the proportion of dead or moribund animals received for slaughter (r = 0.60, P less than 0.05). Isolation of chloramphenicol-resistant salmonella from dairy farms was associated with the use of chloramphenicol at those dairies. We conclude that food animals are a major source of antimicrobial-resistant salmonella infections in humans and that these infections are associated with antimicrobial use on farms.

OBJECTIVE: To review performance characteristics of 12 insulin infusion protocols. RESEARCH DESIGN AND METHODS: We systematically identify and compare 12 protocols and then apply the protocols to generate insulin recommendations in the management of a patient with hyperglycemia. The main focus involves a comparison of insulin doses and patterns of insulin administration. RESULTS: There is great variability in protocols. Areas of variation include differences in initiation and titration of insulin, use of bolus dosing, requirements for calculation in adjustment of the insulin infusion, and method of insulin protocol adjustments. Insulin recommendations for a sample patient are calculated to highlight differences between protocols, including the patterns and ranges of insulin dose recommended (range 27-115 units [mean +/- SD 66.7 +/- 27.9]), amount recommended for glucose readings >200 mg/dl, and adjustments nearing target glucose. CONCLUSIONS: The lack of consensus in the delivery of intravenous insulin infusions is reflected in the wide variability of practice noted in this survey. This mandates close attention to the choice of a protocol. One protocol may not suffice for all patients.

Glycolysis is increased in tumor tissues. [18F]fluoro-2-deoxy-D-glucose (FDG) is a glucose analogue radiopharmaceutical used in positron emission tomography (PET) to trace glucose metabolism. We investigated the sensitivity and specificity of FDG-PET imaging in the diagnosis and staging of lung cancer. One hundred and seven patients who had abnormal chest roentgenograms underwent whole-body PET imaging using FDG. PET scan results were classified as positive or negative based on the presence or absence of increased FDG uptake in the lung and/or in the mediastinum. All 82 patients with lung cancer had increased FDG uptake in the lungs, whereas only 12 of 25 patients with nonmalignant diseases had increased FDG uptake. Sixteen lung cancer patients with mediastinal metastases had increased FDG uptake in the mediastinum, of whom three had no lymphadenopathy on computed tomography of the chest. Sixteen lung cancer patients without mediastinal nodal involvement had no FDG uptake in the mediastinum. Seven of these patients had lymphadenopathy on computed tomography. FDG-PET imaging is 100% accurate in predicting mediastinal involvement in patients with lung cancer. It is 100% sensitive and 52% specific in predicting the malignant nature of a chest radiographic abnormality.