LUNG FUNCTION DECLINE IN COPD IS RELATED TO BACTERIAL LOAD

Patients with chronic obstructive pulmonary disease (COPD) experience a progressive decline in lung function that may be caused in part by airway inflammation. According to a recent prospective cohort study, inflammation due to bacterial colonization in the lower airway worsens lung function in moderate to severe COPD.

Wilkinson et al recruited 30 COPD patients, who used diary cards to record symptoms, peak expiratory flow, and exacerbations. Lung function was measured at baseline and at one year. At these time points, sputum was also collected and analyzed for bacteria.

All sputum samples contained a significant amount of bacteria. Patients who experienced an increase in bacterial load between baseline and follow-up had a greater decrease in forced expiratory volume in one second (FEV1) than did patients with a stable or decreasing bacterial load. The authors also found that the total bacterial count at one year was related to the absolute rate of decline in FEV1.

Haemophilus influenzae was the most commonly isolated pathogen at both sampling times. Fifty percent of patients had entirely different bacterial species at each sampling time, whereas the other 50% demonstrated persistence of a single species.

The decline in FEV1 was 102 mL per year in patients who had different bacterial types at each sample, compared to a decrease of 3.6 mL in the group with a single species. Patients with a higher-than-average bacterial load at follow-up had higher levels of interleukin 8 than did the other patients, suggesting a link between bacterial load, airway inflammation, and decline in FEV1.

Wilkinson TMA, Patel IS, Wilks M, et al. Airway bacterial load and FEV1 decline in patients with chronic obstructive pulmonary disease. Am J Respir Crit Care Med. 2003;167:1090-1095.

FINDINGS OF 22-YEAR EPIDEMIOLOGICAL SEPSIS STUDY

An analysis of data collected by the National Center for Health Statistics shows that during a 22-year period, the incidence of sepsis and the number of sepsis-related deaths increased. Furthermore, both these rates contain racial and sex disparities.

Martin et al used the National Hospital Discharge Survey to identify sepsis cases that occurred from 1979 through 2000. Cases were included based on discharge records that contained a diagnostic code for sepsis.

After adjusting for sex, the authors found that in every year studied, men were more likely than women to have sepsis. Black men had the highest rates of sepsis during the study period (331 cases per 100,000 people), the youngest mean age at onset (47), and the highest mortality rate (23%).

The overall incidence of sepsis increased from 82.7 cases per 100,000 to 240.4 cases per 100,000. This increase was most apparent from 1979 through 1989.

Mortality declined between the start and the end of the study, from 27.8% to 17.9%. However, because of the upsurge in incidence, the number of sepsis-related deaths nearly tripled, from 43,579 to 120,491.

The authors pointed out that the increase in incidence and the number of deaths may have occurred because sepsis has become more commonly recognized and, therefore, more frequently coded in medical records. On the other hand, the expanding use of invasive procedures, immunosuppressants, chemotherapy, and transplantation, as well as the appearance of HIV infection, may have contributed to the growth in incidence and mortality.

Martin GS, Mannino DM, Eaton S, Moss M. The epidemiology of sepsis in the United States from 1979 through 2000. N Engl J Med. 2003;348:1546-1554.

IV EPINEPHRINE IS SAFE FOR ADULTS WITH LIFE-THREATENING ASTHMA

A small, retrospective chart review has found that intravenous epinephrine is safe in adults with acute, life-threatening asthma.

The study, conducted by Smith et al, identified 27 patients between the ages of 19 and 58 who were admitted to one of two emergency departments for acute asthma and given intravenous epinephrine. Clinical data gathered both before and after administration of epinephrine were evaluated, as were any notes on adverse events.

All patients received intravenous epinephrine after initial treatment with a nebulized ß-agonist failed to control their symptoms. Twenty-four of the 27 patients were administered a loading dose of epinephrine that was between 50 mg and 1 mg of a 1:10,000 solution. Fourteen of these patients also received a continuous infusion (usually 1 mg/h). The remaining three patients received infusions only (1 mg over one hour in two cases; 1 to 2 mg/min for two hours in one case).

No deaths or documented adverse events occurred during epinephrine infusion. No patients had echocardiographic changes indicating ischemia, nor were there abnormal increases in cardiac enzyme levels.

Smith et al noted that although intravenous epinephrine appeared to be safe, their study population was small, and only one patient was older than 55 and had atherosclerosis. However, the authors concluded that the danger posed by severe respiratory distress in asthma patients outweighs that of possible adverse events from intravenous epinephrine, even in people with cardiovascular disease.

Smith D, Riel J, Tilles I, et al. Intravenous epinephrine in life-threatening asthma. Ann Emerg Med. 2003;41:706-711.

CPAP IMPROVES SLEEPINESS SCORES IN PATIENTS WITH SEVERE OSA

Continuous positive airway pressure (CPAP) improves both subjective and objective sleepiness scores in patients with obstructive sleep apnea (OSA). Furthermore, the benefits increase with the severity of OSA.

Patel et al performed a meta-analysis of 12 CPAP trials. Subjective sleepiness was measured using the Epworth Sleepiness Scale (ESS), and objective sleepiness was measured using the Multiple Sleep Latency Test and also the Maintenance of Wakefulness Test. The 12 studies included 745 adults with OSA.

Neither the mean apnea/hypopnea index nor baseline ESS score predicted the degree of ESS improvement with CPAP. When the analysis was limited to six trials of patients with severe OSA and significant sleepiness, the improvement in ESS score was significantly greater with CPAP than with placebo.

The authors concluded that CPAP therapy significantly improves subjective and objective sleepiness scores. This conclusion differs from those of previous meta-analyses because the present study included results from recent randomized clinical trials.

Patel SR, White DP, Malhotra A, et al. Continuous positive airway pressure therapy for treating sleepiness in a diverse population with obstructive sleep apnea: results of a meta-analysis. Arch Intern Med. 2003;163:565-571.