SEMIO CH21 TRIGGER

PO2 AT SAT 95%

PO₂ ~80

NORMAL VALUE PO2

80-100

PO2 HYPOXEMIA

60-79

PO2 RESPIRATORY FAILURE

BELOW 60

3 MAIN MECHANISMS OF RESPIRATORY FAILURE

VENTILATION DISORDER

V/Q RATIO DISORDER

ALVEOLOCAPILLARY DIFFUSION DISORDER

HOW MOVES O₂ AND CO₂ → ALVEOLAR HYPOVENTILATION

O₂ ↓ + CO₂ ↑

VENTILATION ASSOCIATED W/ ?

MUSCULAR AND NEUROMUSCULAR PATHOLOGY

ALVEOLAR HYPOVENTILATION CAUSES

HYPOXEMIA + HYPERCAPNIA ( O2 DEFICIENCY + CO2 EXCESS)

IN V/Q RATIO → WHAT MEANS V ? Q ?

V → VENTILATION → AIR REACHING ALVEOLI

Q → PERFUSION → BLOOD REACHING THE ALVEOLI

NORMAL VALUE V/Q RATIO

V/Q = 1

WHEN V/Q BELOW 1 ITS CALLED ?

SHUNT EFFECT

PHYSIOLOGICAL LOGIC BEHIND SHUNT EFFECT ?

V ↓ → FEW OXYGEN REACHES THE ALVEOLI

NORMAL Q = BUT THE BLOOD REACHES PROPERLY ALVEOLIS

TRIGGER SHUNT EFFECT

PERFUSION PRESENT + VENTILATION LOW

WHEN V/Q ABOVE 1 ITS CALLED ?

DEAD SPACE

PHYSIOLOGICAL LOGIC BEHIND DEAD SPACE ?

VENTILATION OK BUT POOR PERFUSION

PARTIAL RESPIRATORY FAILURE =

HYPOXEMIA ALONE

TOTAL RESPIRATORY FAILURE =

HYPOXEMIA + HYPERCPNIA

HYPERCAPNIA VALUE

PCO₂ ABOVE 40

TRIGGER ACUTE RESPIRATORY FAILURE

ABSRUPT ONSET + RESPIRATORY ACIDOSIS + NO METABOLIC COMPENSATION

TRIGGER CHRONIC R° F°

LONG STANDING HYPERCAPNIA + METABOLIC COMPENSATION

DANS UN BLOOD TEST → QUELLE VALEUR ME PERMET DE DIRE QU’IL Y A UNE METABOLIC COMPENSATION ?

QUAND HCO3- EST AU DESSUS DE 25 → METABOLIC COMPENSATION

QUAND ON DIT NO METABOLIC COMPENSATION ON SOUS ENTEND ?

LOW PH

2 MAIN CLINICAL FEATURES OF HYPOXEMIA

CYANOSIS CENTRAL + PERIPHERAL

MULTIORGANIC DYSFUNCTION

3 MAIN CLINICAL FEATURES OF HYPERCAPNIA

HEADACHE + TACHYCARDIA + PERIPHERAL VASODILATATION