10a. Hipoksia
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Transcript of 10a. Hipoksia
Hypoxia
Rudyanto Sedono
ICU Department of Anesthesiology
Faculty of Medicine University of Indonesia
Cipto Mangunkusumo Hospital
Jakarta
Topic related
Hypoxia definition Oxygen transport Type of hypoxia
Hypoxia
Hypoxemia
Insufficient oxygen at the cellular level Inadequate cellular oxygen uptake and
utilizationReduce oxygen for tissue respirationOxygen tension at cellular level is
inadequate
Hypoxia
Hypoxemia
Decreased oxygen partial pressure in arterial
Relative deficiency of oxygen in the arterial blood
Decreased oxygen concentration in the arterial blood
Oxygen is important for maintain aerobic metabolism in cellular level
of the body
Oxygen transport
1. Convection
2. Diffusion
3. Chemical reaction
Oxygen transport from air to the cell
ALVEOLUS
Lung capillary
AIR :
PiO2 : 20.9 % x 760 = 159 mmHg
PiCO2 : 0.04 % x 760 = 0.3 mmHg
PiN2 : 78.6 % x 760 = 597mmHg
PiH2O : 0.46 % x 760 = 3.5 mmHgN2 H2O
O2
PAO2:104 mmHg
CO2
PACO2:40 mmHg
O2
PaO2: 40 mmHg
O2
PaO2: 104 mmHg
CO2PaCO2: 45 mmHg
CO2PaCO2: 40 mmHg
PAN2:573 mmHg
PAH2O:47 mmHg
Diffusionprocess
Convection process
Chemical reaction process of oxygen bound to haemoglobin
Rule of hemoglobin affinity to oxygen.Describe as oxygen dissociation curve
Fick :
DO2 ( ml/min ) = 10 x CO ( L/min ) x CaO2
CaO2 = 1.34 x Hb x SaO2 + 0.003 x PaO2
Normal DO2 ≈ 1000 ml/minCO ≈ 5 L/minHb = 15 gr/100ml
SaO2 100%
Convection process of oxygen from heart-lung to capillary level
Diffusion process of oxygen from capillary to cell
Hypoxia
1. Hypoxic hypoxia
2. Circulatory hypoxia
3. Anemic hypoxia
4. Cytophatic hypoxia
Hypoxic hypoxia
Blood flow to capillary is held constant but oxygen saturation is decreased
Refers to the steps that depend on diffusion of oxygen
Diffusion from the lungs into arterial blood Diffusion from oxygenated capillary blood into
the tissues Low PO2 is the hallmark of hypoxic hypoxia
Caused of hypoxic hypoxia
1. Diffusion limitation
2. Hypoventilation
3. Decreased Fraction Inspiration of Oxygen
4. Shunting
5. V / Q mismatch
6. Contribution of low Mixed Venous Oxygen Saturation
Circulatory Hypoxia
Blood flow into a capillary is decreased while the arterial PO2 remains constant
Depend on cardiovascular system Stimulating the peripheral chemoreceptor Tachycardia, bradycardia, peripheral
vasoconstriction or vasodilatation
Anemic Hypoxia
The arterial hemoglobin concentration ( hematocrit ) decreased Decreased oxygen delivery Perioperative period hematocrit 30% as
optimal
Physiologic response to anemic hypoxia
1. Cardiac output response to hemodilution
- Increased stroke volume
- Increased heart rate
- Decreased peripheral vascular resistance
2. Blood oxygen extraction ratio
- Systemic and microcirculatory level
Cytopathic Hypoxia
Impaired production of ATP despite adequate availability of O2 in the cell
Sepsis condition Impaired mitochondrial function in sepsis Increased expression of various
mitochondrial uncoupling proteins Mitochondrial permeability transition
If you are not
confused, you are not conscious
Thank you