FEATURES: Pa O2 < 6O mm of Hg Pa Co2 – normal or low (< 50 mm Hg) Hydrogen Ion conc. - normal Bicarbonate ion conc. - normal

ACUTE CHRONIC -Acute asthma - emphysema -pulmonary edema - Lung fibrosis -pneumonia - Lymphangitis carcinomatosa -lobar collapse -Rt to Lt shunts -pneumothorax - Brainstem lesion -pulmonary embolus -ARDS

 Ventilation-perfusion(v/q)mismatch Presence of low v/q units contributes to hypoxemia  Intracardiac&intrapulmonary shunts Bypass of deoxygenated blood from alveoli

FEATURES : Pa O2 < 60 mm Hg Pa Co2 > 50 mm Hg Hydrogen Ion conc. - increased Bicarbonate Ion conc. – increased

 ACUTE CHRONIC -Acute exacerbation -COPD of COPD -upper airway obst. -sleep apnoea -acute neuropathies/ -kyphoscoliosis paralysis -narcotic drugs -myopathies -flail chest injury -ankylosing spondylitis

 PaCo2 is dependent on alveolar ventilation  Decrease in minute ventilation in neuro-muscular disorders  Increased airway resistance  Increase in the volume of dead space

- Occurs as a result of lung atelectasis - Most common in peri operative period - After gen.anesthesia decrease in functional residual capacity collapse of dependent lung units

 Frequent changes of position  Non invasive positive pressure ventilation  Chest physiotherapy  Aggressive control of incisional pain

 In shock hypo perfusion of resp. muscles occurs  Up to 40% of CO may be distributed to the resp. muscles

Dyspnoea Confusion and somnolence Restlessness,anxiety,seizures Asterixes Cyanosis Hepatic enlargement,pedaledema Arrhythmias

 Spirometry  Blood Gas analysis: PaO2 PaCo2  Pulse oximetry  Acedemia  Bicarbonate

 Maintenance of airway  Treatment of underlying cause  Oxygen therapy  physiotherapy  Bronchodilators  Antibiotics  Respiratory stimulants

 100% oxygen cannot be used because,  In adults it causes pulmonary oedema & free radical damage causing fibrosis.  premature infants develop retrolental fibroplasia  Hence 35-60% O2 (high flow O2) is used.

In Type II failure Tolerance to raised Co2 develops Depend on hypoxic drive to breathe lower conc. O2(24-28%) used

 Mechanical ventilation negative-pressure - iron lung positive-pressure - Face mask Nasal prongs ETT pressured targeted&volume targeted

Intubation trauma Volutrauma Pneumothorax Lung infection Cardiac failure Weakness of respiratory muscles

WHEN TO CESSATE MECHANICAL VENTILATION ?  Breathe without ventilator support for min.  Resp. rate >35 per min for > 5 min  O2 saturation <90%  Heart rate > 140 per min  Systolic BP 180mm Hg