Noninvasive ventilation: has Pandora’s box been opened?

Exacerbations of COPD are the largest single cause of hospital admission with respiratory disease, and are frequently associated with impaired gas exchange and mortality rates of up to 14%. 1 Acute hypercapnic respiratory failure leads to admissions to intensive care units with a mortality rate of 59% at one year. 2 Noninvasive ventilation (NIV) is a well established and validated therapy for acidotic hypercapnia respiratory failure in COPD, 1 a leading cause of global mortality and morbidity. The use of NIV in patients with acute type II or chronic respiratory failure has increased over the past 10 years. A Cochrane Systematic Review determined the efficacy of NIV in the management of patients with respiratory failure due to an acute exacerbation of COPD. NIV resulted in decreased mortality, decreased need for intubation, and a reduction in treatment failure. 1 However a Royal College of Physicians/British Thoracic Society (RCP/BTS) audit failed to provide evidence that NIV was effective in reducing mortality. The reason for their finding is unclear. 3 There is little convincing evidence for the use of NIV in severe, but stable COPD. In many cases, patients with severe chronic COPD may not tolerate long-term NIV. However, NIV has been accepted as the convention for ventilation support for patients who have developed progressive type II respiratory failure. 4 What is less clear, however, is the quality of how NIV is delivered to patients in hospitals in the UK. The RCP/BTS audit of NIV use in 233 hospitals showed NIV was available in all but 11 hospitals, but only 31% of patients who were admitted with hypercapnic acidotic exacerbations of COPD (pH  7.35) received NIV. 3 A recent update of the guidelines of NIV has reinforced much of current practice but thrown up several interesting questions. 5 Data from the recent BTS National COPD audit (NCROP) demonstrated large gaps in training of staff, provision of written guidelines and the ability to audit practice. 6 Any patient on NIV is classified as receiving Critical Level 2 care, defined as " Patients requiring more detailed observation or intervention including support for a single failed organ system ". This suggests NIV should be administered in an intensive care unit (ICU) or high dependency unit (HDU) setting, but it has been widely recognised that NIV can be successfully used outside the ICU or HDU.