The hospital admission decision for patients with community-acquired pneumonia. Results from the pneumonia Patient Outcomes Research Team cohort study.

BACKGROUND: The hospital admission decision directly influences the magnitude of resource use in patients with community-acquired pneumonia, yet little information exists on how medical practitioners make this decision. OBJECTIVES: To determine which factors medical practitioners consider in making the hospital admission decision and which health care services they believe would allow ambulatory treatment of low-risk hospitalized patients with community-acquired pneumonia. METHODS: Medical practitioners responsible for the hospital admission decision for low-risk patients with community-acquired pneumonia were asked to describe patient characteristics at initial examination that influenced the hospitalization decision, and to identify the health care services that would have allowed initial outpatient treatment of hospitalized patients. RESULTS: A total of 292 medical practitioners completed questionnaires for 472 (76%) of the 624 low-risk patients eligible for this study. Although all patients had a predicted probability of death of less than 4%, practitioners estimated that 5% of outpatients and 41% of inpatients had an expected 30-day risk of death of more than 5%. Univariate analyses identified 3 practitioner-rated factors that were nearly universally associated with hospitalization: hypoxemia (odds ratio, 173.3; 95% confidence interval, 23.8-1265.0), inability to maintain oral intake (odds ratio, 53.3; 95% confidence interval, 12.8-222.5), and lack of patient home care support (odds ratio, 54.4; 95% confidence interval, 7.3-402.6). In patients without these 3 factors, logistic regression analysis demonstrated that practitioner-estimated risk of death of more than 5% had a strong independent association with hospitalization (odds ratio, 18.4; 95% confidence interval, 6.1-55.7). Practitioners identified home intravenous antibiotic therapy and home nursing observation as services that would have allowed outpatient treatment of more than half (68% and 59%, respectively) of the patients initially hospitalized for treatment. CONCLUSIONS: Practitioners' survey responses suggest that the availability of outpatient intravenous antimicrobial therapy and home nursing care would allow outpatient care for a large proportion of low-risk patients who are hospitalized for community-acquired pneumonia. These data also suggest that methods to improve practitioners' identification of low-risk patients with community-acquired pneumonia could decrease the hospitalization of such patients. Future studies are required to help physicians identify which low-risk patients could safely be treated in the outpatient setting on the basis of clinical information readily available at presentation.

Clearance of Pneumocystis carinii cysts in acute P carinii pneumonia: assessment by serial sputum induction.

STUDY OBJECTIVES: To determine the feasibility of repeat sputum induction in acute Pneumocystis carinii pneumonia (PCP) and to define the rate of clearance of P carinii cysts from the respiratory tract of HIV-seropositive patients with acute PCP. DESIGN: Prospective cohort evaluation. SETTING: University medical center. PARTICIPANTS: Twenty-four HIV-seropositive subjects with acute PCP. MEASUREMENTS: Sputum induction for P carinii 2, 3, 4, and 6 weeks after initial diagnosis, and follow-up for 1 year. RESULTS: Eighty-eight percent of subjects had residual cysts at 2 weeks, 76% at 3 weeks, 29% at 4 weeks, and 24% at 6 weeks postdiagnosis. A prior AIDS-defining illness (p = 0.033) or prior PCP (p = 0.004) predicted relapse within 6 months, but persistent cysts at 3 weeks did not; 8 of 16 sputum-positive subjects and 1 of 5 sputum-negative subjects experienced a relapse within 6 months (p = 0.34). Secondary prophylaxis with trimethoprim-sulfamethoxazole was associated with a reduced risk of relapse. CONCLUSIONS: Serial sputum induction coupled with direct fluorescent antibody staining is a feasible, noninvasive method of respiratory tract surveillance for the eradication of P carinii during and after acute PCP. Three-quarters of HIV-seropositive patients with acute PCP have persistent cysts in their lungs at the end of antimicrobial treatment, despite clinical recuperation, but only one quarter have residual cysts 6 weeks postdiagnosis. A prior AIDS-defining illness and prior PCP are positively associated, and subsequent trimethoprim-sulfamethoxazole prophylaxis is negatively associated, with relapse within 6 months, while persistent organisms at 3 weeks do not appear to be a significant predictor of relapse risk.

Low dose aminophylline selectively increases upper airway motor activity in normals.

Because certain pharmacologic agents differentially influence upper airway and diaphragm motor activity, we postulated that the adenosine antagonist theophylline might preferentially increase alae nasi activity in human subjects. Using a double-blinded, randomized, placebo controlled design, we studied the effect of low dose aminophylline (1-2 mg/kg) on alae nasi and diaphragm surface electromyographic (EMG) activity. Seven healthy volunteers served as subjects for two trials on separate days. Subjects breathed from a close circuit while end tidal PCO2 was held constant in the eucapnic range. During each trial we recorded EMG signals from the alae nasi and diaphragm before and after intravenous infusion of either aminophylline or placebo. After the administration of aminophylline, the mean alae nasi EMG signal increased 87 +/- 31 (SD)% (P less than 0.005) while the mean diaphragmatic EMG signal did not change. There was no significant change in either the alae nasi or diaphragmatic EMG signal after placebo. There was no change in minute ventilation, tidal volume, or respiratory frequency after either aminophylline or placebo. We speculate that low dose aminophylline produces a selective increase in upper airway muscle activity through stimulation of the reticular activating system.

Alpha-methyldopa selectively reduces alae nasi activity.

1. Sedatives such as the benzodiazepines and alcohol reduce upper airway muscle activity. We hypothesized that a sedating antihypertensive, alpha-methyldopa, might have similar effects. To investigate this hypothesis we studied the effect of alpha-methyldopa on alae nasi electromyographic (EMG) activity during hypercapnia. 2. We studied ten healthy subjects and three subjects with obstructive sleep apnoea during CO2-stimulated breathing. In a preliminary study four subjects demonstrated a fall in alae nasi EMG activity 4 h after the ingestion of 500 mg of alpha-methyldopa during CO2 rebreathing. 3. In six additional normal subjects and three subjects with obstructive sleep apnoea, we studied the alae nasi EMG activity during steady-state hypercapnia with PCO2 held constant 5 torr (0.7 kPa) above baseline. On 2 separate days we studied subjects before and 2 h after they had ingested 750 mg of alpha-methyldopa or placebo. 4. In the normal subjects the mean alae nasi EMG activity fell by 34% 2 h after ingestion of alpha-methyldopa (P less than 0.05) without a change in other ventilatory parameters. 5. In the sleep apnoea group the individual mean alae nasi EMG activity fell 16-49%, with ventilation and tidal volume falling in one patient. 6. We conclude that alpha-methyldopa selectively reduces upper airway motor activity.