Nomad: Hypoxias & Asphyxia

NomadPARA:Respi:HypoxiasphyxiaNomadPARA:Respi:Hypoxiasphyxia 11

HYPOXIAS & HYPOXIAS & ASPHYXIAASPHYXIA

ByBy

Dr. M. Anthony David MD,Dr. M. Anthony David MD,

Professor of PhysiologyProfessor of Physiology


HYPOXIAHYPOXIA A condition where there is A condition where there is

decreased Oxygen supply decreased Oxygen supply to the tissues is called as to the tissues is called as ““hypoxiahypoxia””


HYPOXIA: CLASSIFICATION HYPOXIA: CLASSIFICATION

1.1. Hypoxic Hypoxia Hypoxic Hypoxia:: Arterial P OArterial P O22 is less. is less.

2. 2. Anemic HypoxiaAnemic Hypoxia:: Decreased Hemoglobin causing Decreased Hemoglobin causing OO22

carriagecarriage

3. 3. Stagnant HypoxiaStagnant Hypoxia:: Due to slow & low blood flow.Due to slow & low blood flow.

4. 4. Histotoxic HypoxiaHistotoxic Hypoxia:: Tissue toxins deny OTissue toxins deny O2 2 to the cells.to the cells.


TYPES OF HYPOXIA

1. HYPOXIC HYPOXIA1. HYPOXIC HYPOXIA

2. ANEMIC HYPOXIA2. ANEMIC HYPOXIA

3. STAGNANT HYPOXIA3. STAGNANT HYPOXIA

4. HISTOTOXIC HYPOXIA4. HISTOTOXIC HYPOXIA


HYPOXIC HYPOXIAHYPOXIC HYPOXIA The arterial POThe arterial PO22

is decreased.is decreased. This may be This may be

due to:due to:1. Decreased 1. Decreased

Atmospheric Atmospheric POPO22::

High AltitudeHigh Altitude Closed roomClosed room


Arterial POArterial PO2 2 decreased due to:decreased due to:

2. Decreased Ventilation:2. Decreased Ventilation: Respiratory Paralysis.Respiratory Paralysis. Bronchial AsthmaBronchial Asthma EmphysemaEmphysema

3. Defective Gas exchange:3. Defective Gas exchange: Pulmonary EdemaPulmonary Edema PneumoconiosisPneumoconiosis

All these cause a All these cause a decreased partial decreased partial pressure of Oxygen pressure of Oxygen and so and so Hypoxic Hypoxic Hypoxia.Hypoxia.


HYPOXIC HYPOXIAHYPOXIC HYPOXIA

Commonest type.Commonest type. CAUSES: PHYSIOLOGICAL:CAUSES: PHYSIOLOGICAL:

• High altitudes.High altitudes.

• > 3000 Mts above MSL: Alv. PO> 3000 Mts above MSL: Alv. PO22: 60mm : 60mm Hg.Hg.

• Causes irritabilityCauses irritability


HYPOXIC HYPOXIA: HYPOXIC HYPOXIA: PATHOLOGICAL CAUSESPATHOLOGICAL CAUSES

Lung Failure due to:Lung Failure due to:• Pulmonary Fibrosis.Pulmonary Fibrosis.• Ventilation/Perfusion imbalance.Ventilation/Perfusion imbalance.

Ventilatory Pump Failure:Ventilatory Pump Failure:• FatigueFatigue• Mechanical defectsMechanical defects• Depression of respiratory centers.Depression of respiratory centers.

Shunts.Shunts.


TYPES OF HYPOXIA






ANEMIC HYPOXIAANEMIC HYPOXIA A decrease in hemoglobin or RBC A decrease in hemoglobin or RBC

count causes decreased Oxygen count causes decreased Oxygen carriage and so hypoxia.carriage and so hypoxia.

Can also be due to Can also be due to CO PoisoningCO Poisoning..• CO combines irreversibly with Hb.CO combines irreversibly with Hb.

Abnormal Hemoglobins such as Abnormal Hemoglobins such as Sickle HbSickle Hb can also cause Anemic can also cause Anemic Hypoxia.Hypoxia.


TYPES OF HYPOXIA






STAGNANT HYPOXIASTAGNANT HYPOXIA Also called “Also called “IschemicIschemic” or “” or “Hypo-perfusion Hypo-perfusion

HypoxiaHypoxia”.”. Blood flow to tissues is Blood flow to tissues is slow or low.slow or low. The Oxygen reaching the tissues per unit The Oxygen reaching the tissues per unit

time is less.time is less. This situation is seen in:This situation is seen in:

• Heart failureHeart failure• Venous obstructionVenous obstruction

May lead to May lead to Adult Respiratory Distress Adult Respiratory Distress Syndrome Syndrome if it occurs in the lungs.if it occurs in the lungs.


TYPES OF HYPOXIA






HISTOTOXIC HYPOXIAHISTOTOXIC HYPOXIA Oxygen is available at tissue Oxygen is available at tissue

levelslevels But the cells cannot use it due to But the cells cannot use it due to

a toxic agent.a toxic agent. Seen inSeen in Cyanide poisoning.Cyanide poisoning.


Cyanide inhibits the intracellular Cyanide inhibits the intracellular enzyme, “enzyme, “Cytochrome oxidaseCytochrome oxidase””

This problem can be treated withThis problem can be treated with Methylene BlueMethylene Blue..• Methylene blue converts Cyan Hb into Methylene blue converts Cyan Hb into

CyanmetHb which is nontoxic.CyanmetHb which is nontoxic.

HISTOTOXIC HYPOXIAHISTOTOXIC HYPOXIA


EFFECTS OF HYPOXIAEFFECTS OF HYPOXIA Severe Hypoxia < 20mm HgSevere Hypoxia < 20mm Hg

• In 10 – 20 seconds: Loss of In 10 – 20 seconds: Loss of consciousness.consciousness.

• In 4 – 5 minutes: DEATHIn 4 – 5 minutes: DEATH Mild Hypoxia:Mild Hypoxia:

• Symptoms are similar to alcoholismSymptoms are similar to alcoholism• Impaired Judgment.Impaired Judgment.• Drowsiness.Drowsiness.• Dulled sensitivity to pain.Dulled sensitivity to pain.

EFFECTS OF HYPOXIAEFFECTS OF HYPOXIA


Headache. Headache. Nausea & Nausea &

Vomitting.Vomitting. Tachycardia.Tachycardia. AnorexiaAnorexia Disorientation.Disorientation. Excitement.Excitement.

EFFECTS OF MILD HYPOXIAEFFECTS OF MILD HYPOXIA


CYANOSISCYANOSIS

Bluish discoloration of the skin & Bluish discoloration of the skin & mucous membranes.mucous membranes.

Cause: the presence ofCause: the presence of Reduced Reduced Hemoglobin Hemoglobin in the blood.in the blood.

Seen only when the Seen only when the absoluteabsolute amount amount of Reduced Hb is of Reduced Hb is > 5 Grams/dLt> 5 Grams/dLt..

Is more common therefore inIs more common therefore in PolycythemiasPolycythemias..


OXYGEN THERAPYOXYGEN THERAPY Given to patients of Hypoxic hypoxia Can be given through:

• A Nasal catheter.• Venturi mask.

Pure Oxygen is not given A mixture of Air & Oxygen is given. Useful in all cases of Hypoxic

Hypoxia.


ASPHYXIAASPHYXIA ““Improper aeration of blood Improper aeration of blood

continued for sometime produces continued for sometime produces two pathological changes:two pathological changes:• Hypoxia : Hypoxia : O O22

• Hypercapnia : Hypercapnia : CO CO22


TYPES OF ASPHYXIATYPES OF ASPHYXIA LOCAL: Due to obstruction of blood LOCAL: Due to obstruction of blood

supply:supply:• Too tight tourniquet, for too long.Too tight tourniquet, for too long.• Blue painful, swollen congested limb.Blue painful, swollen congested limb.

GENERAL:GENERAL:• ACUTE:ACUTE:

Strangulation: Occlusion of tracheaStrangulation: Occlusion of trachea Airtight room: suffocation.Airtight room: suffocation.


GENERAL ASPYXIA: CHRONICGENERAL ASPYXIA: CHRONIC

Chronic Lung Disease.Chronic Lung Disease. Chronic Bronchiectasis.Chronic Bronchiectasis. EmphysemaEmphysema

• Decreased Alveolar VentilationDecreased Alveolar Ventilation COCO22 content content OO22 content content


ASPHYXIA: STAGESASPHYXIA: STAGES I STAGE:I STAGE:

• Violent Respiratory EffortsViolent Respiratory Efforts• Tachypnea & Hyperpnea.Tachypnea & Hyperpnea.• HypoxiaHypoxia• Loss of consciousnesss.Loss of consciousnesss.

II STAGE:II STAGE: Sympathetic dischargeSympathetic discharge• Hypertension & TachycardiaHypertension & Tachycardia• Ventricular fibrillationsVentricular fibrillations• ConvulsionsConvulsions


ASPHYXIA : STAGE IIIASPHYXIA : STAGE III Gasping :Gasping :

• Slow deep inspirationSlow deep inspiration HyporeflexiaHyporeflexia Pupillary DilatationPupillary Dilatation HypotensionHypotension BradycardiaBradycardia Cardiac ArrestCardiac Arrest Death.Death.


FAILURE OF ONE, IS FAILURE OF ONE, IS FAILURE OF ALL!FAILURE OF ALL!

BRAIN FAILURE

CARDIAC FAILURE

RESPIRATORYFAILURE


Date post:	14-Oct-2014
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Nomad: Hypoxias & Asphyxia

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