Respiratory System Flashcards
What is the relation of Pulm. artery to bronchus at each lung hilum ??
“RALS”
Right bronchus = Anterior
Left bronchus = Superior
CARINA - is Posterior to ascending aorta & Anteromedial to descending aorta
What are the lung
- Volumes
- Capacities
TV ( 6 to 8 ml/kg = 500ml)
IRV (
ERV (
Residual Volume (TLC minus VC)
Insp. Capacity (IRV + TV)
Func. Residual C (RV + ERV)
Vital C (IRV + TV + ERV)
TLC (IRV + TV + ERV + RV = VC + RV)
How much is the normal Peak Expiratory Flow ??
520 to 700 L/min
Define Lung capacity ?
Sum of >= 2 physiological volumes
- there are 4 volumes & 4 capacities
What is Physiological dead space (VD) ??
VD = TV * (PaCO2 - PeCO2)/PaCO2
(PeCO2 = expired air CO2)
- It is approx. = to Anatomical dead space in normal lungs
What is Transfer factor ??
Rate at which gas will diffuse from alveoli ==> blood
- Carbon monoxide is used to test rate of diffusion
What are the causes of raised TLCO (Total gas transfer) ??
Raised - “MAPLE- H”
- Male gender
- Asthma
- Pulm. Haemorrhage (Wegener’s, Goodpastures)
- Polycythaemia
- Left- Right Cardiac shunt
- Exercise
- Hyperkinetic states
What are the causes of lower TLCO ??
Lower “LAPE”
- Lower Cardiac Output
- Anaemia
- Pulm. FIBROSIS
- Pulm. OEDEMA
- Pulm. EMOBOLI
- Pneumonia
- Emphysema
- Cryptogenic Organizing Pneumonia
What conditions cause Increased KCO (transfer coefficient) with a normal/ reduced TLCO ??
Pneumonectomy/ Lobectomy
Kyphosis/ Scoliosis
Neuromuscular weakness
Ankylosis of costo-vertebral joints (Ank. Spon.)
What are the ABCs of obstructive lung disease ??
Asthma
Bronchiectasis
Bronchiolitis obliterans
COPD
Eg. of Restrictive Lung disease ??
ARDS
Asbestosis
Infant RDS
Kypho-scoliosis (eg. Ank. Spon.)
Pulm. Fibrosis
Neuromuscular disorders
Sarcoidosis
Severe Obesity
Salicylate poisoning hallmark ??
Early- Resp. Alkalosis (Resp. centre stimulation
Late - Met. Acidosis (direct acid effect + Acute renal failure)
What is O2 dissociation curve ??
Relationship b/w Percentage of saturated Hb & partial pressure of O2 in blood
- NOT affected by Hb conc.
Cause of
- Left Shift
- Rt. Shift
Left –Lower O2 delivery ==> Low CADET
Rt. – RaiseD O2 delivery ==> Raised CADET
CADET - Co2, Acid, (2,3-DPG), Exercise, Temp.,
How does Salbutamol work ??
Beta receptor AGONIST (relaxes bronchial SM by effects on Beta 2 receptors)
How does Ipratropium work ??
Muscarinic ACh receptor BLOCKERS
- Relaxes Bronchial SM
TIOTROPIUM is long acting
Methylxanthines or Aminophyllines action ??
Non-specific PD inhibitor (increases cAMP)
Non-specific Adenosine receptor blockers
Drug for Aspirin induced asthma
Leukotriene ANTAGONISTS
- Montelukast, Zafirlukast
- Anti-inflammatory + bronchodilator action
Contraindication for Leukotriene antagonists ??
Churg-Strauss synd.
CRP levels and starting antibiotics in Pneumonia ??
< 20 mg/L = no antibiotics
20 to 100 mg/L = consider DELAYED antibiotics prescription
> 100 mg/L = OFFER antibiotics
in admitted pts., CRP monitoring determines response to Rx.
Rx. of Low-severity Pneumonia ??
1st line = AMOXICILLIN
Macrolides/ Tetracycline if Penicillin allergics
5 days course
Rx. for Moderate severity Pneumonia ??
Dual Abx. Therapy
- Amoxicillin + Macrolides
- 7 to 10 days course
Rx. for High severity Pneumonia ??
Dual Abx. Therapy
- Beta-lactamase stable penicillin (Co-amoxiclav, Ceftriaxone, Piptaz)+ Macrolides
Klebsiella Pneumonia features
- Gram -ve rods, part of normal gut flora
- MC in Alcoholics, DM, Aspiration cases
- RED-CURRANT Jelly sputum
- often affects UPPER Lobes
- Lung abscess, Empyema common