American Thoracic Society Journal news tips for August 2004 (second issue)

08/06/04

Combined Antibiotic Lowers Death Rate Significantly in Critically Ill Patients with Pneumoccal Bacteremia

Combination antibiotic therapy improved survival significantly among critically ill patients who had severe pneumonia with complicating bactermia, according to published results from an international prospective, observational study. The researchers studied 844 consecutive patients with bactermic pneumococcal pneumonia who were treated in 21 hospitals in 10 countries on 6 continents. (Bactermia is the presence of bacteria in the bloodstream, which is a relatively common problem. Usually, the bacteria are rapidly removed by white blood cells. However, sometimes there are too many bacteria to be removed easily and they overwhelm the white cells, resulting in a serious disease complication.) Among the 844 adult patients with bactermia due to Streptococcus pneumoniae in the study, there were 94 who were critically ill. The combination antibiotic therapy received by 47 resulted in a 14-day mortality rate of 23.4 percent, as contrasted with the 55.3 percent mortality rate for the 47 on monotherapy. The authors said that the improvement in survival was independent of the country of origin, intensive care unit support, class of antibiotics, or in vitro activity of the antibiotics prescribed. Among the balance of patients who were not critically ill, the 14-day mortality rate was not significantly different between either the combination or monotherapy treatment groups. Overall, of the 844 patients, 16.5 percent (139) died by Day 14 of their treatment. The study appears in the second issue for August 2004 of the American Thoracic Society's peer-reviewed American Journal of Respiratory and Critical Care Medicine.

Screening for Obstructive Sleep Apnea in Commerical Drivers

In an effort to develop a simpler test to identify commercial truck drivers who suffer from severe sleep apnea and who might fall asleep at the wheel, medical investigators have developed a two-stage strategy combining questions about the symptoms of sleep apnea, with body weight data, plus a test for oxygen concentration in the blood when needed. From this combination, they produced a predictive rate of 91 percent for the disorder. To develop their new test, researchers studied 406 commercial drivers in order to uncover cases of sleep apnea before a crash. Utilizing a level of five or more sleep apnea episodes per hour to define any apnea, 114 drivers were shown to be affected by mild to moderate apnea; in addition, 19 drivers had 30 or more episodes per hour to demonstrate severe sleep apnea. (Sleep apnea is a serious sleep disorder in which an affected person pauses in breathing during sleep for 10 seconds or longer and then resumes breathing after a very brief arousal.) According to the authors, sleepiness accounts for between 31 to 41 percent of the major crashes of commercial vehicles. In 2001, large trucks were involved in 429,000 crashes. Nearly 5,000 were fatal. The researchers said that the simplest strategy they employed depended first on responses to questions about three apnea-related symptoms. Then they looked at body mass index (BMI) data because obesity is a major obstructive sleep apnea factor. In addition, they examined a risk score that combined information about symptoms with BMI as well as about age and sex. When they added oximetry to measure oxygen level in the blood, the test was 91 percent sensitive. If oximetry was not employed, it was 81 percent predictive. They called their new tool the multivariable apnea prediction index. The study appears in the second issue for August 2004 of the American Thoracic Society's peer-rerviewed American Journal of Respiratory and Critical Care Medicine.

Opportunistic Pathogen Seems to Make Airflow Restriction Worse in Chronic Obstructive Pulmonary Disease Patients

Researchers have demonstrated that there is a strong association between severity of airflow restriction in patients with chronic obstructive pulmonary disease (COPD), especially those with severe illness, and colonization with an opportunistic pathogen called Pneumocystis. (In COPD, patients have persistent obstruction of the airways associated with either emphysema or chronic bronchitis, caused by years of smoking.) The investigators examined lung tissue from 68 smokers with varying severity of COPD who underwent lung resection or lung transplantation. In addition, they looked at tissue from 44 control subjects who received lung transplants for diagnoses other than COPD. They checked the Pneumocystis colonization rates from both sets of patients. (Pneumocystis is an opportunistic pathogen that causes pneumonia in immunocompromised individuals and, according to the authors, could be a pathogen involved in the progression of COPD.) Using nested polymerase chain reaction techniques, they detected colonization in about 37 percent of the 30 smokers who had severe COPD (11 patients). This figure contrasted sharply with the detection of Pneumocystis in 5.3 percent of the 38 smoking patients with normal lung function or less severe COPD (2 patients). In the 44 control patients who had other diagnoses than COPD, 9.1 percent (4 patients) were colonized with the pathogen. The study appears in the second issue for August 2004 of the American Thoracic Society's peer-reviewed American Journal of Respiratory and Critical Care Medicine.

Source: Eurekalert & others

Last reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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