Cost effectiveness of ward based non-invasive ventilation for acute exacerbations of chronic obstructive pulmonary disease: economic analysis of randomised controlled trial

OBJECTIVE

To evaluate the cost effectiveness of standard treatment with and without the addition of ward based non-invasive ventilation in patients admitted to hospital with an acute exacerbation of chronic obstructive pulmonary disease.

DESIGN

Incremental cost effectiveness analysis of a randomised controlled trial.

SETTING

Medical wards in 14 hospitals in the United Kingdom.

PARTICIPANTS

The trial comprised 236 patients admitted to hospital with an acute exacerbation of chronic obstructive pulmonary disease and mild to moderate acidosis (pH 7.25-7.35) secondary to respiratory failure. The economic analysis compared the costs of treatment that these patients received after randomisation.

MAIN OUTCOME MEASURE

Incremental cost per in-hospital death.

RESULTS

24/118 died in the group receiving standard treatment and 12/118 in the group receiving non-invasive ventilation (P=0.05). Allocation to the group receiving non-invasive ventilation was associated with a reduction in costs of 49362 pounds sterling (78741 dollars; 73109 euros), mainly through reduced use of intensive care units. The incremental cost effectiveness ratio was -645 pounds sterling per death avoided (95% confidence interval -2310 pounds sterling to 386 pounds sterling), indicating a dominant (more effective and less costly) strategy. Modelling of these data indicates that a typical UK hospital providing a non-invasive ventilation service will avoid six deaths and three to nine admissions to intensive care units per year, with an associated cost reduction of 12000-53000 pounds sterling per year.

CONCLUSIONS

Non-invasive ventilation is a highly cost effective treatment that both reduced total costs and improved mortality in hospital.

Non-invasive ventilation in acute exacerbations of chronic obstructive pulmonary disease: long term survival and predictors of in-hospital outcome

BACKGROUND

Non-invasive ventilation (NIV) reduces the need for intubation and the mortality associated with an exacerbation of chronic obstructive pulmonary disease (COPD). This study aimed to identify factors that could be used to stratify patients according to their risk of requiring invasive mechanical ventilation. The second aim was to determine the long term survival of patients treated with and without NIV.

METHODS

In this prospective multicentre randomised controlled trial 118 patients were allocated to standard treatment and 118 to NIV between November 1996 and September 1998. Arterial blood gas tensions and respiratory rate were recorded at enrolment and after 1 and 4 hours. Prognostic factors were identified using logistic regression analysis. All patients were followed until death or 1 January 1999.

RESULTS

At enrolment the H+ concentration (OR 1.22 per nmol/l, 95% CI 1.09 to 1.37, p<0.01) and Paco2 (OR 1.14 per kPa, 95% CI 1.14 to 1.81, p<0.01) were associated with treatment failure. Allocation to NIV was protective (OR 0.39, 95% CI 0.19 to 0.80). After 4 hours of treatment improvement in acidosis (OR 0.89 per nmol/l, 95% CI 0.82 to 0.97, p<0.01) and fall in respiratory rate (OR 0.92 per breaths/min, 95% CI 0.84 to 0.99, p=0.04) were associated with success. Median length of survival was 16.8 months in those treated with NIV and 13.4 months in those receiving standard treatment (p=0.12). The trend in improved survival was attributable to prevention of death during the index admission.

CONCLUSION

Initial pH and hypercapnia can be used to stratify groups of patients according to their risk of needing intubation. NIV reduces this risk and progress should be monitored using change in respiratory rate and pH. The long term survival after NIV is sufficiently good to render treatment appropriate.

Non-invasive ventilation in acute exacerbations of chronic obstructive pulmonary disease: long term survival and predictors of in-hospital outcome

BACKGROUND

Non-invasive ventilation (NIV) reduces the need for intubation and the mortality associated with an exacerbation of chronic obstructive pulmonary disease (COPD). This study aimed to identify factors that could be used to stratify patients according to their risk of requiring invasive mechanical ventilation. The second aim was to determine the long term survival of patients treated with and without NIV.

METHODS

In this prospective multicentre randomised controlled trial 118 patients were allocated to standard treatment and 118 to NIV between November 1996 and September 1998. Arterial blood gas tensions and respiratory rate were recorded at enrolment and after 1 and 4 hours. Prognostic factors were identified using logistic regression analysis. All patients were followed until death or 1 January 1999.

RESULTS

At enrolment the H(+) concentration (OR 1.22 per nmol/l, 95% CI 1.09 to 1.37, p<0.01) and PaCO2 (OR 1.14 per kPa, 95% CI 1.14 to 1.81, p<0.01) were associated with treatment failure. Allocation to NIV was protective (OR 0.39, 95% CI 0.19 to 0.80). After 4 hours of treatment improvement in acidosis (OR 0.89 per nmol/l, 95% CI 0.82 to 0.97, p<0.01) and fall in respiratory rate (OR 0.92 per breaths/min, 95% CI 0.84 to 0.99, p=0.04) were associated with success. Median length of survival was 16.8 months in those treated with NIV and 13.4 months in those receiving standard treatment (p=0.12). The trend in improved survival was attributable to prevention of death during the index admission.

CONCLUSION

Initial pH and hypercapnia can be used to stratify groups of patients according to their risk of needing intubation. NIV reduces this risk and progress should be monitored using change in respiratory rate and pH. The long term survival after NIV is sufficiently good to render treatment appropriate.

Comparison of three outcomes instruments in children

SUMMARY

The purpose of this study was to compare prospectively the distributions, validity, and discriminative ability of three pediatric outcome questionnaires. Consecutive patients completed the Activities Scales for Kids (ASK), the Child Health Questionnaire Parent Form (CHQ-PF-28), and the Pediatrics Outcomes Data Collection Instrument (PODCI). The scores of the three instruments were compared with each other and with parents' and clinicians' ratings. Of 210 patients, 166 (79%) completed the three questionnaires. The CHQ-PF-28 had a different distribution than the other two questionnaires and showed both floor and ceiling effects. The ASK and PODCI instruments were highly correlated and discriminated better than the CHQ-PF-28, with fewer floor and ceiling effects. Each questionnaire, however, seemed to be measuring slightly different things.

One year period prevalence study of respiratory acidosis in acute exacerbations of COPD: implications for the provision of non-invasive ventilation and oxygen administration

BACKGROUND

Non-invasive ventilation (NIV) reduces mortality and intubation rates in patients with chronic obstructive pulmonary disease (COPD) admitted to hospital with respiratory acidosis. This study aimed to determine the prevalence of respiratory acidosis in patients admitted with COPD, to draw inferences about oxygen therapy, and to determine the need for NIV services for acute COPD in typical UK hospitals.

METHODS

This one year prospective prevalence study identified patients with COPD aged 45-79 years inclusive who were admitted to Leeds General Infirmary, St James's University, and Killingbeck Hospitals, Leeds between 1 March 1997 and 28 February 1998. The prevalence of respiratory acidosis and the relationship with oxygenation are described. Other outcomes included intensive care use and in hospital mortality. From this data population prevalence estimates were determined for respiratory acidosis, from which the need for NIV in a typical district general hospital was modelled.

RESULTS

983 patients were admitted, 11 of whom required immediate intubation. 20% of the remaining 972 had a respiratory acidosis. Acidosis was associated with subsequent admission to the intensive care unit (ICU): pH<7.25, OR 6.10 (95% confidence interval (CI) 1.19 to 31.11); pH 7.25-7.30, OR 8.73 (95% CI 2.11 to 36.06). pH was inversely correlated with arterial oxygen tension (PaO(2)) in the 47% of patients who were hypercapnic, with a PaO(2) of >10 kPa being associated with acidosis in most hypercapnic patients. 80% remained acidotic after initial treatment, giving an age/sex specific prevalence for England and Wales of 75 (95% CI 61 to 90)/100 000/year for men aged 45-79 years and 57 (95% CI 46 to 69)/100 000/year for women. Modelling the need for NIV for all COPD patients indicates that a typical UK hospital will admit 90 patients per year with acidosis of which 72 will require NIV.

CONCLUSIONS

In patients with acute COPD the PaO(2) should be maintained at 7.3-10 kPa (SaO(2) 85-92%) to avoid the dangers of hypoxia and acidosis. If all COPD patients with a respiratory acidosis (pH<7.35) after initial treatment are offered NIV, a typical UK hospital will treat 72 patients per year.

Early use of non-invasive ventilation for acute exacerbations of chronic obstructive pulmonary disease on general respiratory wards: a multicentre randomised controlled trial

BACKGROUND

Within the intensive-care unit, non-invasive ventilation (NIV) can prevent the need for intubation and the mortality associated with severe episodes of chronic obstructive pulmonary disease (COPD). The aim of this study was to find whether the introduction of NIV, early after the admission on a general respiratory ward, was effective at reducing the need for intubation and the mortality associated with acute exacerbations of COPD.

METHODS

We did a prospective multicentre randomised controlled study comparing NIV with standard therapy in patients with mild to moderate acidosis. NIV was administered on the ward with a simple non-invasive ventilator and a standardised predefined protocol. Patients were recruited from 14 UK hospitals over 22 months.

FINDINGS

236 patients were recruited, 118 received standard therapy alone and 118 additional NIV. The two groups had similar characteristics at enrolment. The use of NIV significantly reduced the need for intubation as defined by the failure criteria. 32/118 (27%) of the standard group failed compared with 18/118 (15%) of the NIV group (p=0.02). In-hospital mortality was also reduced by NIV, 24/118 (20%) died in the standard group compared with 12/118 (10%) in the NIV group (p=0.05). In both groups pH, PaCO2, and respiratory rate improved at 4 h (p<0.01). However, NIV led to a more rapid improvement in pH in the first hour (p=0.02) and a greater fall in respiratory rate at 4 h (p=0.035). The duration of breathlessness was also reduced by NIV (p=0.025).

INTERPRETATION

The early use of NIV for mildly and moderately acidotic patients with COPD in the general ward setting leads to more rapid improvement of physiological variables, a reduction in the need for invasive mechanical ventilation (with objective criteria), and a reduction in in-hospital mortality.

Trauma registry databases: a comparison of data abstraction, interpretation, and entry at two level I trauma centers

BACKGROUND

A key part of a viable trauma system is the Trauma Registry (TR), used for research, education, and performance improvement. This study sought to assess the consistency of data abstraction, interpretation, and entry by two hospitals with an identical TR database program.

METHODS

In phase I, trauma service personnel were queried as to how data were abstracted and entered into the TR. In phase II, a 1-year retrospective review was conducted of TR data for two trauma centers in San Antonio, Texas.

RESULTS

The phase I review revealed substantial variances in the coding and abstracting of TR data in 30 of the 500 elements (6%). Phase II demonstrated that, because of these variances, considerable differences resulted in coded types and causes of injury.

CONCLUSION

This study illustrates that these variances can impact attempts to combine databases, establish norms, or assess institutional outcomes. To ensure the standardization and accuracy of this valuable information, changes may be required. Recommendations include standardization and education. A uniform trauma registry or national certification may be necessary.

One year's trauma mortality experience at Brooke Army Medical Center: is aeromedical transportation of trauma patients necessary?

The purpose of this study was to review whether air ambulance transportation of trauma patients to the Brooke Army Medical Center (BAMC) level I trauma center contributed to maintaining national mortality standards in the trauma care of these patients. Aeromedical transportation is considered a standard-of-care component of regional trauma systems throughout the United States. Pooled trauma database information from 792 consecutive ambulance-transported trauma patients received at BAMC during the fiscal year from October 1, 1995, to September 30, 1996, were reviewed. The 792 trauma patients were composed of 687 patients transported by ground ambulance and 105 patients who received helicopter aeromedical evacuation. Aeromedical evacuation was associated with increased levels of prehospital medical care and faster transportation than ground ambulance service. The mortality rates (immediate, early, and late deaths) of both ambulance groups were compared with national mortality standards using the internationally recognized Trauma and Injury Severity Score methodology, based on the Major Trauma Outcome Study in 1986 and validated in 1992. The Z test for independent populations demonstrated no statistically significant difference between BAMC trauma mortality rates for either ambulance group compared with national trauma mortality rates. The results suggest that aeromedical evacuation of the more severely injured patients farthest from the BAMC trauma center resulted in mortality rates that met national standards.

Amplification of DNA markers from evolutionarily diverse genomes using single primers of simple-sequence repeats

The abundance and scattered distribution of simple-sequence repeats (SSR) in eukaryotic genomes prompted us to explore the use of SSR-based oligonucleotide primers in single primer amplification reactions. In a pilot experiment, 23 primers were used across a panel of evolutionarily diverse eukaryotic genomes, including grapes, lettuce, tomato, pine, maize, salmon, chicken, Holstein cows and humans. The primers were 16-20 bases in length and represented SSRs of di-, tri-, tetra-, and pentanucleotide repeats. The results showed that tetranucleotide repeat primers were most effective in amplifying polymorphic patterns. Of 11 such primers tested, 70% produced polymorphic patterns from the DNA of one or more species. Primers representing a combination of two tetranucleotide repeats, or compound microsatellites, were equally effective. The polymorphisms contained in such fingerprints were able to identify individuals of vertebrate species as well as lines or varieties of plants. Inheritance of the polymorphic bands was studied in a maize recombinant inbred population, DE811 x B73. Thirty-two polymorphic bands, derived from two amplification patterns, were mapped as dominant markers on an existing RFLP map of the same population. The bands were distributed across nine of the ten chromosomes.

Prevention of immunoglobulin production by allotype-dependent T cells

Adoptive lymphocyte transfers between Iga, Igb and Igd allotype-congenic mouse strains revealed host barriers against the production of certain donor allotypes. First, as recipients of Igb cells, Iga and Igd mice permitted the production of donor Ig-4b but not that of Ig-1 b. The apparent mediators of this Ig-1 b barrier were T cells specific for Ig- 1 b determinants on B cells. Additional cell transfers showed Iga mice to have a second barrier against allotype production by Igd donor cells. Reciprocal cell transfers showed Igb and Igd mice to have comparatively weak barriers against Iga-producing cells. As host barriers were absent in mice deficient for T cells (athymic nude mice), it appears that they are T cell-mediated. Further, the allotype-dependence of such barriers means that the antigens responsible must be under the control of allotype-linked genes. The regulatory implications of this for the immune system are discussed.