pulmonary function tests

obstructive lung disease

issues in bronchi or bronchioles, air can’t get out

obstructive disease examples

bronchial asthma, COPD, bronchiectasis, bronchiolitis

restrictive lung disease

issue with lung parenchyma, air can’t get in

restrictive lung disease example

lung fibrosis

PFT indications

evaluate sx, assess bronchodilators and respiratory impairment, monitoring disease course and therapy, risk evaluation prior to surgery

PFT contraindication

increased myocardial demand, increased intra-thoracic/intra-abdominal pressure

PFT methods

spirometry, plethysmography

spirometry

device with mouthpiece with small electronic machine to assess air volume

spirometry complication

syncope

spirometry steps

use nasal clip and have patient breathe in and out as hard as possible 3 times

plethysmography

gold standard for measuring lung volumes

patient sits in air tight box to basically do spirometry

PFT bronchodilator preparation stoppage time

SABA 4-6 hours before

SAMA 12 hours before

LABA 24 hours

ultra-LABA 36 hours

LAMA 36-48 hours

types of PFTs

bronchodilator usage, bronchoprovocation challenge

bronchoprovocation challenge indication

patient has normal spirometry but you still suspect asthma

bronchoprovocation challenge meds

methacholine, mannitol

FVC

amount of air exhaled forcefully and quickly after inhaling as much as possible

FEV1

expired air during first second of FVC test

MCC of FEV1 reduction

airway OBSTRUCTION

vital capacity

total volume of air that can be exhaled after inhaling as much as possible

peak expiratory flow rate

max flow generated by forceful exhalation from full inspiration

tidal volume

amount of air inhaled or exhaled during normal breathing

residual volume

air left in lungs after exhaling as much as possible

total lung capacity

total volume of lungs when filled with as much air as possible

PFT interpretation requirements

consider height, age, gender, race

consider quality of test

PFT interpretation steps

determine if FEV1/FVC is low/normal

determine if FVC is low

confirm restrictive pattern

determine reversibility

establish DDx

compare to previous

determining if FEV1/FVC is normal

obstructive disease: low ratio and normal FVC

restrictive disease: normal ratio, low FVC

determining if FVC is low

obstructive disease: low ratio and normal FVC

restrictive disease: normal ratio and low FVC

confirming restrictive pattern

find lung volumes, if low may be ILD

determining reversibility of obstructive defect

administer bronchodilator (asthma = reversible, COPD = irreversible)

peak expiratory flow rate

measures degree of obstruction in those with respiratory conditions

peak expiratory flow rate indication

monitoring asthma/COPD

incentive spirometry indication

patients with issues taking full breath in like post op, chest trauma

atelectasis potential cause

lack of deep breathing

atelectasis complication

pneumonia

MCC of post op fever

atelectasis