NEW YORK (Reuters Health) – A UK national audit shows that in chronic obstructive pulmonary disease (COPD), non-invasive ventilation (NIV) is often used – or not used – inappropriately, and patients are dying as a result.
NIV “is one of the few medical interventions that is proven to save lives in severely ill COPD patients admitted to hospital with respiratory failure,” lead researcher Dr. C. Michael Roberts of London’s Royal College of Physicians told Reuters Health by email.
However, he said, “some patients who would benefit from NIV do not receive it at all or receive it late, whilst others receive it inappropriately and should be considered for alternative medical management.”
In a November 12th online paper in Thorax, he and his colleagues report on 9716 patients hospitalized across the country for COPD exacerbations during three months in 2008.
Guidelines recommend that NIV begin within one hour of admission when respiratory acidosis persists despite maximum medical therapy.
Twelve percent of patients (1168) received respiratory support, mainly with NIV alone. Of the 1678 patients who were acidotic on admission, 750 (45%) were treated with NIV.
There were 453 patients with lower acidotic blood gas levels both on admission and subsequently; only 70% of them received NIV. This means that “nearly one third of those with the greatest evidence base for effectiveness did not,” the authors say.
Out of 465 patients with a normal pH on admission who later became acidotic, only 47% received NIV.
On the other hand, 131 patients had a normal PaCO2 and pure metabolic acidosis underlying a deranged pH – and 11% of these received NIV.
Furthermore, said Dr. Roberts, “Some of the patients in the audit had their illness made worse by the administration of high levels of oxygen in the ambulance or accident and emergency department.”
Deaths were more frequent than what’s been reported in randomized trials. Hospital mortality was 25% overall for patients receiving NIV but 39% for those with late onset acidosis. It was higher in all acidotic groups receiving NIV (26%) than those treated without (14%).
Only 4% of patients receiving NIV who died had invasive mechanical ventilation. Such ventilation was employed in just 122 (1%) of patients overall.
“There are already national guidelines for the evidence based use of NIV,” continued Dr. Roberts, “and there is an urgent need for more training to be given to emergency medical and nursing staff on the indications for and timely use of NIV in COPD patients.”
“In the case of the UK, we have seen ‘mission creep’ from the original trial evidence to apply the intervention (NIV) to patients outside the entry criteria for the research studies, with potentially serious adverse outcomes for these patients.”
The study, he pointed out, “demonstrates that national audit programs are invaluable in gathering data that highlights deficiencies in care that once identified can be remedied with the potential to save lives.”
In fact, Dr. Roberts added that he is now taking part in the recently launched European audit of COPD care. This project, which is being managed by the European Respiratory Society in Lausanne, Switzerland, involves 13 countries besides the U.K.
Moniek Haan, representing the society, told Reuters Health, “Evidence is growing that COPD patient care varies widely between different hospitals and between different European countries, and is frequently not consistent with published guidelines. There are many different service models and it remains unknown which deliver the best results for patients.”
The participants hope to publish their reports and analyses by mid 2011.
Reference:
Acidosis, non-invasive ventilation and mortality in hospitalised COPD exacerbations
Thorax 2010.
