Lung function and NIV

Question 1

What is spirometry

Answer 1

• test used to establish objective measures of lung function.
• different breathing exercises into a machine that measures volumes of air and flow rates and produces a report.
• Reversibility testing involves giving a bronchodilator (i.e. salbutamol) prior to repeating the spirometry to see the impact this has on the results.

Question 2

What is FEV1

Answer 2

• forced expiratory volume in 1 second
• amount of air a person can exhale as fast as they can in 1 second.
• It will be reduced if there is any obstruction to the air flow out of the lungs.

Question 3

What is FVC

Answer 3

• forced vital capacity
• total amount of air a person can exhale after a full inhalation
• measure of the total volume of air that the person can take in to their lungs. It will be reduced if there is any restriction on the capacity of their lungs.

Question 4

what is considered obstructive lung disease

Answer 4

• FEV1 is less than 75% of FVC (FEV1:FVC ratio < 75%).
• he person may have a relatively good lung volume but air is only able to move in and out of the lungs slowly due to obstruction.

Question 5

What are obstructive airway diseases

Answer 5

• asthma
• COPD
• Cystic fibrosis

Question 6

What is restrictive airway disease

Answer 6

• FEV1 and FVC are equally reduced and FEV1:FVC ratio > 75% this suggests restrictive lung disease
• restriction to the ability of the lungs to expand and take air in.

Question 7

what are som3 causes of restrictive lung disease

Answer 7

Interstitial lung disease
Neurological (i.e. motor neurone disease)
Scoliosis or chest deformity
Obesity

Question 8

What is peak flow

Answer 8

• simple way of demonstrating how much obstruction to airflow is present in the patient’s lungs

Question 9

What is non-invasive ventilation

Answer 9

• an alternative to full intubation and ventilation to support the lungs in respiratory failure due to obstructive lung disease
• full face mask or a tight fitting nasal mask to blow air forcefully into the lungs and ventilate them without having to intubate them
• not pleasant, but less invasive than intubation

Question 10

What is bilevel positive airway pressure BIPAP?

Answer 10

• involves a cycle of high and low pressure to correspond to the patients inspiration and expiration
• used where there is type 2 respiratory failure e.g. COPD

Question 11

What is the criteria for starting BiPAP

Answer 11

• Respiratory acidosis (pH < 7.35, PaCO2 >6) despite adequate medical treatment.
• Initiated by a registrar or above
• Repeat an ABG 1 hour after every change and 4 hours after that until stable

Question 12

Contraindications for BiPAP

Answer 12

• untreated pneumothorax
• structural abnormality or pathology affecting the face, airway or GI tract
• CXR prior to NIV ALWAYS

Question 13

What is CPAP (continuous positive airway pressure)

Answer 13

• It provides continuous air being blown into the lungs that keeps the airways expanded so that air can more easily travel in and out
• used to maintain the patient’s airway in conditions where it is prone to collapse.

Question 14

indications for CPAP

Answer 14

Obstructive sleep apnoea
Congestive cardiac failure
Acute pulmonary oedema