pulsus paradoxus - seen in
4. pericarditis 5. croup
asthma - histology
asthma drugs
role of corticosteroids (fluticosine, budesonide) in asthma therpay
asthma - albuterol used in
- during acute exacerbation
asthma - ipratropium vs tiotropium according to action
tiotropium is long acting
montelukast, zafirukast mechanism of action
block leukotriene receptor (CysLT1)
Zileuton mechanism of action / SE
5-lipoxygenase pathway inhibitor. Block conversion of arachnoid acid to leukotrienes
- hepatotoxic
adenosine receptor antagonists
2. caffeine
theophylline adverse effects
think asthma as a diagnosis when
inspiratory reserve volume (IRV)
air that can still be breathed in after normal inspiration (3.3L)
Expiratory reserve volume (ERV)
air that can be breathed out after normal expiration (1L)
Inspiratory capacity (IC)
inspiratory reserve volume (IRV) + tidal volume (TV)
3.8L
Vital capacity (VC)
Maximum volume of gas that can be expired after a maximal inspiration (4.8L)
inspiratory reserve volume (IRV) + tidal volume (TV) + Expiratory reserve volume (ERV)
Functional residual capacity (FRC)
Volume of gas in lungs after normal expiration (2.2L) Residual volume (RV) + Expiratory reserve volume (ERV)
minute ventilation (Ve)
total volume of gas that entering lungs per minute
Ve = tidal volume x respiratory rate
Alveolar ventilation (Va)
volume of gas per unit time that REACHES ALVEOLI
Va = (tidal volume - physiological dead space) x respiratory rate
situations that alter FEV1/FVC
decreased: obstructive lung disease
increased: restrictive lung disease
IRV is used during
exercise
Lung volumes that cannot be measured by spirometry
Causes of increased Vital capacity
acromegaly
physiologic dead space equation
tidal volume (Vt) x (arterial PCO2- expired PCO2)/ arterial PCO2
physiologic dead space definition
anatomic dead space of conducting airways plus alveolar dead space
Volume of inspired air that does not take part in gas exchange
alveolar dead space distribution
apex of healthy lung is largest contributor of dead space