respiratory failure

Zanzibar university• Prepared :

• RN, BSc,N. Abdulla khamis ngwali

• Supervised by:

• Madame saada ali

Respiratory Failure

• Respiratory failure is inadequate gas exchange by the respiratory system, with the result that levels of arterial oxygen, carbon dioxide or both cannot be maintained within their normal ranges.

• A fall in blood oxygenation is known as hypoxemia.

• A rise in arterial carbon dioxide levels is called hypercapnia.

Cont…

• There are some diseases and conditions that affect breathing can cause respiratory failure. Examples include COPD (chronic obstructive pulmonary disease) and spinal cord injuries. COPD prevents enough air from flowing in and out of the airways. Spinal cord injuries can damage the nerves that control breathing.

Classification of Respiratory Failure

• Hypoxemia- inadequate O2 transfer

– PaO2 of 60mmHg or less when pt. Receiving 60%

or greater O2

• Hypercapnia- insufficient CO2 removal

Increases PaCO2.

Copyright © 2007, 2004, 2000, Mosby, Inc., an affiliate of Elsevier Inc. All Rights Reserved.

Cont…

Fig. 68-2

Inhaling

Affects PaO2

Exhaling

Affects PCO2

Factors that affects Hypoxemic Respiratory Failure

• V/Q Mismatch

• Shunt

• Diffusion Limitation

• Alveolar Hypoventilation- inc. CO2 and dec.

PO2

Range of V/Q Relationships

Ventilation Perfusion Mismatch(V/Q)

• An imbalance between alveolar ventilation and pulmonary capillary blood flow.

• Normal V/Q =1 (1ml air/ 1ml of blood)

• Ventilation=lungs

• Perfusion or Q=perfusion

• Pulmonary Embolus- (VQ scan)

Shunt

• In medicine, a shunt is a hole or a small passage which moves, or allows movement of fluid from one part of the body to another.

Cont…

• There are 2 Types;

– 1. Anatomic- passes through an anatomic channel of

the heart and does not pass through the lungs

exercise.

– e.g. ventricular septal defect. (The hole that occurs

in the wall of the heart that separates the heart's

lower chambers (septum) and allows blood to pass

from the left to the right side of the heart)

Cont..

–2. Intrapulmonary shunt- blood flows through

pulmonary capillaries without participating in

gas exchange ex: alveoli filled with fluid.

–Patients with shunts are more hypoxemic

than those with VQ mismatch and they may

require mechanical ventilators.

Diffusion Limitations

• Gas exchange is compromised by a process that

thickens or destroys the membrane

– 1. Pulmonary fibrosis

– 2. ARDS(Acute respiratory distress syndrome)

A classic sign of diffusion limitation is hypoxemia during

exercise but not at rest.

Diffusion Limitation

Alveolar Hypoventilation

• Alveolar hypoventilation is a rare disorder in which a

person does not take enough breaths per minute. Mainly

due to hypercapnic respiratory failure but can cause

hypoxemia

• Increased pCO2 with decreased PO2

• Restrictive lung disease

• CNS diseases

• Neuromuscular diseases.

Factors that affects HypercapnicVentilatory Failure.

1. Abnormalities of the airways and alveoli-

air flow obstruction and air trapping

– Asthma, COPD, and cystic fibrosis

2. Abnormalities of the CNS- suppresses drive to

breath

3. Drugs e.g. narcotics,

4. Head injury and spinal cord injury

Causes

Respiratory failure can occur as a result of:

• Conditions that affect the nerves and muscles

that control breathing. Examples include

muscular dystrophy, amyotrophic lateral sclerosis

(ALS), spinal cord injuries, and stroke.

• Damage to the tissues and ribs around the lungs.

An injury to the chest can cause this damage.

Cont…

• Problems with the spine, such as scoliosis (a

curve in the spine). This condition can affect the

bones and muscles used for breathing.

• Drug or alcohol overdose. An overdose affects

the area of the brain that controls breathing.

During an overdose, breathing becomes slow

and shallow.

Cont…

• Lung diseases and conditions, such

as COPD (chronic obstructive pulmonary

disease),pneumonia, and cystic fibrosis. These

diseases and conditions can affect the flow of air

and blood into and out of lungs.

• Acute lung injuries. For example, inhaling

harmful fumes or smoke can injure lungs.

Signs and Symptoms of Respiratory Failure

Respiratory failure is accompanied by a number of symptoms including:• Bluish coloration of the lips or fingernails• Confusion or loss of consciousness• Fainting or change in level of consciousness or

lethargy• Fatigue• Irregular heart rate (arrhythmia)• Rapid breathing (tachypnea) or shortness of

breath

Management of the patient with respiratory failure

• O2 therapy

• Position

• Mobilization of secretions

• Positive pressure ventilation(PPV)

O2 Therapy

Oxygen therapy is the administration of oxygen at

concentrations greater than that in room air to treat

or prevent hypoxemia (not enough oxygen in the

blood).

• Mechanism of action

– Reverses hypoxemia

O2 Therapy

Position of the patient

• The patient should be stay upright position

• Positioning- 45 degrees or recliner chair or bed

Mobilization of secretions

Positive pressure ventilation

• The provision of air under pressure by a mechanical respirator, a machine designed to improve the exchange of air between the lungs and the atmosphere.