A randomized multi-arm repeated-measures prospective study of several modalities of portable oxygen delivery during assessment of functional exercise capacity

BACKGROUND

Ambulatory oxygen is an important component of long-term oxygen therapy. Pulse-dose technology conserves oxygen and thus increases the operation time of a portable oxygen system.

METHODS

We tested 4 ambulatory oxygen systems (Helios, HomeFill, FreeStyle, and the compressed-oxygen cylinder system we regularly provide for long-term oxygen therapy at our Veterans Affairs hospital) with 39 subjects with stage-IV chronic obstructive pulmonary disease. Each subject performed one 6-min walk test with each oxygen system, and we measured blood oxygen saturation (via pulse oximetry [S(pO(2))]), heart rate, and modified Borg dyspnea score, and surveyed the subjects' preferences about the oxygen systems. We also studied whether the 2 systems that provide gas with a lower oxygen concentration (from a home concentrator or portable concentrator) showed any evidence of not providing adequate oxygenation.

RESULTS

With all 4 systems the mean pre-walk S(pO(2)) at the prescribed pulse-dose setting was 95-96%. The mean post-walk S(pO(2)) was 88-90% after each of the 4 walk tests. Between the 4 systems there were no statistically significant differences between the pre-walk-versus-post-walk S(pO(2)) ( = .42). With each system, the pre-walk-versus-post-walk S(pO(2)) difference was between -8% and -6%.

CONCLUSIONS

Between these 4 ambulatory oxygen systems there were no significant differences in S(pO(2)), walk time, or walk distance, and there was no evidence of inadequate oxygenation with the 2 systems that provide a lower oxygen concentration.

The rate and risk of heat-related illness in hospital emergency departments during the 1995 Chicago heat disaster

OBJECTIVES

To conduct an Emergency Department (ED)-based treated prevalence study of heat morbidity and to estimate the rate and risk of heat morbid events for all Chicago MSA EDs (N = 95; 2.7 million visits per year).

METHODS

ED patient log data were compiled from 13 randomly selected hospitals located throughout the Chicago MSA during the 2 weeks of the 1995 heat disaster and from the same 2-week period in 1994 (controls). Measurements included: age, sex, date, and time of ED service, up to three ICD-9 diagnoses, and disposition.

RESULTS

Heat morbidity for Chicago MSA hospital EDs was calculated at 4,224 (95% CI = 2964-5488) cases. ED heat morbidity increased significantly 5 days prior to the first heat-related death. In 1995, there was an increase in the estimated relative risk for the city = 3.85 and suburbs = 1.89 over the control year of 1994.

CONCLUSIONS

Real time ED-based computer automated databanks should be constructed to improve public health response to infectious or noninfectious outbreaks. Rapid area-wide M&M tabulations can be used for advancing the effectiveness of community-based prevention programs, and anticipating hospital ED resource allocation.

Multicenter study of case finding in elderly emergency department patients

OBJECTIVES

To assess the feasibility of a brief comprehensive case-finding program for detecting functional, cognitive, and social impairments among elderly ED patients and to estimate the prevalence of unknown, undetected, or untreated impairments elderly patients may have.

METHODS

A multicenter prospective study conducted at five private and public hospital EDs in five different communities across the country. Patients aged 60 years and older released to their homes during 52 randomly selected evening and weekend shifts between February 1 and April 30, 1993, were eligible for the case-finding program. They were evaluated by medical students who received special training (instructional videotape, supervised examinations, and conference calls) in the administration of a standardized 17-item protocol that included an interview and simple tests of function. The patients' physicians were notified of the screening results and were asked to return a one-month follow-up questionnaire. The physicians answered whether the presumed problem had been confirmed and whether a treatment plan for a new problem had been developed.

RESULTS

Patient acceptance of the case-finding program was good; 252 of 338 eligible patients (75%) agreed to participate, and 281 conditions were detected for 242 screened patients (96%). The most frequently reported problems were with: performing the activities of daily living (79%); vision (55%); lack of influenza vaccination (54%); home environment (49%); mental status (46%); general health (41%); falls (40%); and depression (36%). The physicians returned questionnaires for 153 patients (63%); 76 patients (50%) were evaluated at follow-up visits, during which 47 newly identified problems (62%) were confirmed and treatment plans were developed for 25 problems (53%) among 21 patients. A mean time of 17.7 +/- 10.2 minutes was required to complete the screen.

CONCLUSIONS

A brief comprehensive case-finding program for functional, cognitive, and social impairment among elderly ED patients is feasible. The screening uncovered a significant amount of morbidity among older patients visiting EDs.

Geriatric patient emergency visits. Part II: Perceptions of visits by geriatric and younger patients

OBJECTIVES

To compare group perceptions of reasons for emergency department care, ED use patterns, and the effect of illness on self-care ability for elderly and younger adult patients.

DESIGN

Patient survey.

SETTING

Six geographically distinct US hospital EDs.

PARTICIPANTS

From each site, a stratified sample (approximately 7:3) of elderly (65 years and older) and nonelderly (21 to 64 years old) control ED patients treated during the same time period was contacted.

METHODS

Three hundred ninety-nine elderly patients and 172 adult controls were interviewed using a structured survey instrument. Groups were compared using chi 2 analysis and the Mann-Whitney U test.

RESULTS

Both the elderly and the control patients (49% versus 38%) commonly stated that the most important reason for coming to the ED was because they were "too sick to wait for an office visit." Of patients with a regular physician, both groups often were referred to the ED by their primary care provider (35% versus 26%). While the elderly had more visits to their primary care provider (3.3 versus 2.9 visits; P less than .00001), there was no difference in the number of ED visits (1.5 versus 1.6 visits) during the preceding six months. Of those released from the ED, more elderly noted deterioration in their ability to care for themselves as a result of their illness (21% versus 11%; P less than .03).

CONCLUSION

The elderly use the ED for reasons similar to those for younger adults. Often they feel too ill to wait for an office visit or are referred in by their primary care provider. Elderly patients more commonly have difficulty with self care after release home, and emergency physicians must plan accordingly.

Geriatric patient emergency visits. Part I: Comparison of visits by geriatric and younger patients

OBJECTIVES

To describe emergency department use by the elderly, to define problems associated with emergency care of the elderly, and to compare these results with those for younger adult patients.

DESIGN

Retrospective, controlled chart review.

SETTING

Six geographically distinct US hospital EDs.

PARTICIPANTS

From each site, a stratified sample (approximately 7:3) of elderly (65 years or older) and nonelderly (21 to 64 years old) control patients treated during the same time period was used.

METHODS

Standardized review of ED records and billing charges. Comparisons of elderly and control patient groups using chi 2 analysis and Mann-Whitney U test (alpha = 0.05).

RESULTS

Four hundred eighteen elderly patients and 175 nonelderly controls were entered into the study. The elderly were more likely to arrive by ambulance (35% versus 11%; P less than .00001). More elderly than controls presented with conditions of either high or intermediate urgency (78% versus 61%; P less than .0003). The elderly more frequently presented with comorbid diseases (94% versus 63%; P less than .00001). Other findings for the elderly included a longer mean stay in the ED (185 versus 155 minutes; P less than .003), higher laboratory (78% versus 53%; P less than .00001) and radiology (77% versus 52%; P less than .00001) test rates, higher mean overall care charges ($471 versus $344; P less than .00001), and an admission rate (47% versus 19%; P less than .00001) twice that of younger adults.

CONCLUSION

Resource use and charges associated with emergency care are higher for the elderly than for younger patients. Increases in emergency resources and personnel or improvement in efficiency will be needed to maintain emergency care at present levels as the US population continues to grow and age.