Non-Invasive Ventilation (NIV) for Chronic Obstructive Pulmonary Disease (COPD)

Non-Invasive Ventilation (NIV) for Chronic Obstructive Pulmonary Disease (COPD)

What is Chronic Obstructive Pulmonary Disease (COPD)?

In the lungs, the airways branch out like a tree, and each branch further spreads out into many small, balloon-like air sacs. In a normal healthy person, the airways are clear and open, and the air sacs are elastic and springy. Each breath fills the air sacs like balloons and each breadth out deflates the air sacs.

Chronic obstructive pulmonary disease (COPD) is a lung disease in which the lungs are damaged, making it hard to breathe. When a person has COPD, the airways and air sacs lose their shape and become floppy. The amount of air that goes in and out becomes lesser as the airways and air sacs lose their elasticity. The walls between the air sacs are destroyed or swollen and the cells in the airway produce too much mucus (sputum), clogging the airways. This condition develops slowly, and it may be years before any symptoms (like shortness of breath) occur. Hence, COPD is often only diagnosed in middle-aged or older people.¹ COPD is a major cause of death and illness, and in Singapore, it ranked 7th in hospital admissions and mortality rate in 2004².

Causes and Complications of COPD

Smoking is the most common cause of COPD. Most people with COPD are smokers or former smokers and approximately 80 to 90 percent of COPD deaths are due to smoking. Risk factors of COPD include air pollution, second-hand smoke, dust, chemicals, history of childhood respiratory infections and heredity. There is presently still no cure for COPD and the damage to the airways and lungs cannot be reversed, though there are possibilities to slow the damage, prevent complications and alleviate the symptoms.³

When there is an abrupt increase in symptoms of shortness of breath and/or wheezing and increase in production of purulent sputum (sputum containing pus), this is known as an acute exacerbation. Hospitalization may be required if the symptoms are severe and artificial ventilation is performed on the patient.

Non-Invasive Ventilation (NIV)

The traditional way to artificially ventilate a COPD patient has been to use endotracheal intubation. Intubation involves putting in of a hollow tube into the airway past the larynx and into the trachea to help the patient to breathe. While intubation is a rapid, simple and non-surgical technique that helps maintains airway patency, it is an invasive procedure associated with complications like laryngeal trauma, spinal cord and vertebral column injury, nerve injury and even death.

A more recent approach, called Non-Invasive Ventilation (NIV), has profoundly changed the management and outcome of these COPD patients.⁴, ⁵ NIV is used in a conscious, cooperative patient. In this method, oxygen is delivered through a mask that forms a seal around the nose or mouth and nose. The mask can be periodically removed and the patient's natural protection against secretions getting into the lower airway is preserved⁶.

The use of NIV was shown to reduce complications, intubation rates, length of stay in the ICU, and mortality compared to intubation⁷. The incidence of nosocomial pneumonia during NIV is also lower than in intubated patients. In addition, NIV has the advantage that it can be applied intermittently, avoids the need for sedation, and allows the patient to eat, drink and talk. It now has a history of use in many different clinical environments including the emergency room, general wards, intermediate respiratory care units and in intensive care units⁸.

NIV in NUH

NUH has an active history in COPD patient management. It had begun patient education in 2001 to aid the patient in managing their condition. In the same year, it also helped optimize drug treatment to prevent exacerbations.

To implement NIV in NUH, specific training is necessary for optimal administration. This is important in both in the medical ward, the emergency department, and the ICU. A specific approach is required to optimise the ventilation delivered, to decrease leaks, and to help the patient to understand, accept, and tolerate the technique. In addition, the speed in which NIV is applied makes the process easier. Once administered, patients will then require careful and continuous monitoring by a consultant

NUH's NIV program rolled out in the ICU in 2002 and in the Emergency dept in 2003. COPD management programmes were also extended to the Emergency Department and Treatment Unit (EDTU) and the development of the Hospital@Home programme in 2005.

Results of NIV treatments in NUH

After implementation of NIV in NUH, the rates of endotracheal intubation in patients with severe respiratory distress in the Intensive Care Unit (ICU), was halved. This subsequently led to a decrease in death rates and the lengths of stays in the hospital.

NUH found that an increase use of Non Invasive Ventilation was associated with a reduction in death rates. There was also a further drop in the death rates when the NIV treatment was moved from the ICU to the Emergency Department. When it was further implemented in the EDTU and Hospital @Home programs, it also led to significant falls in readmission rates.

Success of NIV is measured in two particular areas (1) reduction in mortality rates, and, (2) treatment failures.

A Cochrane systematic review and meta-analysis of NIV to treat respiratory failure resulting from exacerbations of COPD reveals that reduction in mortality varies from 26% to 64% internationally,. In NUH, our mortality was reduced by 50%, which compares very well against international benchmarks.
In terms of treatment failure i.e., inability to prevent intubation and MICU admission by using NIV, NUH achieved a rate of 27.6%. This is very much lower than the international range of 38% to 67% as reported in the Cochrane review.
Beyond lowering death rates, NUH also estimates that in a cohort of 300 patients with COPD, the reduction in hospitalization alone resulted in savings of more than $1 million for the patients and the hospital per year.

Footnotes:

1. Chronic Obstructive Pulmonary Disease (COPD) Fact Sheet, August 2006, American Lung Association; http://www.lungusa.org/site/pp.asp?c=dvLUK9O0E&b=35020
2. Launch Of The Nhg Integrated Chronic Obstructive Pulmonary Disease (Nice) Programme; National Healthcare Group; 18 May 2005; http://www.nhg.com.sg/pressreleases/pr18052005.htm
3. COPD; National Heart Lung and Blood Institute; Disease and Conditions Index; Jan 2006; http://www.nhlbi.nih.gov/health/dci/Diseases/Copd/Copd_WhatIs.html
4. Bott J, Carroll MP, Conway JH, et al. Randomised controlled trial of nasal ventilation in acute ventilatory failure due to chronic obstructive airways disease. Lancet 1993;341:1555-1557
5. Brochard L, Mancebo J, Wysocki M, et al. Noninvasive ventilation for acute exacerbations of chronic obstructive pulmonary disease. N Engl J Med 1995;333:817-822
6. Therapy For Acute Exacerbations; Pulmonology Channel, 7 Mar 2007, http://www.pulmonologychannel.com/copd/acuteexacerbation.shtml
7. Brochard L, Mancebo J, Wysocki M, et al. Noninvasive ventilation for acute exacerbations of chronic obstructive pulmonary disease. N Engl J Med 1995;333:817-822
8. Noninvasive ventilation in acute exacerbations of COPD; M. W. Elliott; EUROPEAN RESPIRATORY REVIEW, 2005;14: 39-42; http://err.ersjournals.com/cgi/content/abstract/14/94/39

This material does not cover all information and is not intended as a substitute for professional care. Please consult your physician on any matters regarding your health.