Comprehensive Oxygen Therapy

The aim of oxygen therapy is to supplement the existing oxygen in the lung which is usually low  

INDICATIONS

1. Obstructive airway diseases like asthma.

2. Congestive cardiac failure.

3. Severe haemorrhage leading to severe anaemia.

4. Shock and collapse.

Asphyxia and suffocation.

6. Hyperpyrexic states as in thyrotoxicosis.

7. Pneumotoxic coli (distension of bowels due to air).

8. High altitudes as in the moon.

9. Pre-oxygenation in anaesthesia.

10. Certain premature babies.

11. Hyperbaric oxygen is given in cases of:

(a) Gas gangrene.

(b) Carbon monoxide poisoning.

(c) Frost bote.

(d) Migraine

Methods of giving oxygen:

The method depends on the concentration of oxygen needed.

Low Concentration:-

1. Ventimask

2. Ambu bag.

3. Oxygen tent.

4. Head tent.

B. High Concentration:-

1. Nasal catheter.

2. MC mask, poly masks.

3. T-piece.

4. Anaesthetic machine.

5. Endotracheal tube.

6. Tracheostomy.

COMPLICATIONS OF OXYGEN THERAPY

1. Risk of fire and explosion

2. In neonates, it causes retrolental fibroplasia, that is, the formation of the fibrovascular membrane posterior to the lens. or collapse of air vesicles of the lung can occur due to

3. Atelectasis rapid absorption through the alveoli.

4. Uncontrolled oxygen therapy may lead to emphysema.

5. Hyperbaric oxygen may cause convulsion.

ROLE OF THE NURSE IN OXYGEN THERA:

Ensure that no naked light is brought need the patient or the oxygen cylinder as the gas is highly inflammable.

2. No smoking is allowed.

3. In children wad, toys that sparkle should not be given to children receiving oxygen especially.

4. No vigorous combing of the hair near the oxygen cylinder or patient as this may produce an electrostatic effect.

5. No rubbing of nylon material on the cylinder for the electrostatic effect.

6. Patient must be closely monitored.

7. Give only the prescribed concentration and all punt of oxygen.

8. Handle the oxygen cylinder carefully as the gas is under pressure.

9. Electrical apparatus close to the patient must be checked and maintained in safe working condition.

10. Alcohol and ether must not be applied to the kin of a patient receiving oxygen therapy.

THE ANATOMY AND PHYSIOLOGY OF THE EYE WITH SOME EYE PROBLEMS

• Upper eyelid
• Rectus muscle
• Suspensory
• Sclerotic la ‘er
• Ligament
• Choroid layer
• Aqueous humour
• Retina
• Eye-lash
• Fovea (: rails lens
• Cornea
• Vitreous
• Iris
• Humour
• Topic nerve
• Blindspot
• Conjunctiva
• Ciliary body
• Lower eye

Fig 10.1; vertical section of the human eye

The eye is a spherical organ that is connected to the brain by the optic nerve. It is responsible for the perception of light stimuli. 

Different parts of the eye

• Conjunctiva:- This is a thin epithelium that lines the eyelid and it continues across the surface of the eyeball. It protects the inner part of the eye. It gets inflamed during infection instead of the entire eye
• Cornea:- This is a thick transparent tissue. It is a continuation of the sclera in front of the eye.
• Aqueous Humour:- This is a fluid occupying the front of the eye. The fluid contains salt, sugar and protein and supplies food and oxygen to the lens and cornea. The fluid is more watery than the vitreous humour. It also helps to maintain the shape of the eye.

• Ciliary Muscle:- This muscle pulls on the lens. Varying its tension makes the lens either thinner or thicker from back to front. This alters the focal length of the lens and results in proper accommodation.

• Iris:- This is a continuation of the choroid in front. It forms a partition between the anterior and posterior chambers of the eye. The iris regulates the amount of light that enters the eye. It is pigmented and therefore responsible for the colour of the eye. The space between the two iris is called the pupil, and through here light rays Enter the eye.
• Lens:- The lens is a transparent biconvex and elastic structure. It is held in position by the suspensory ligament. Its main function is that of focusing of image on the retina.
• Vitreous Humour:- Unlike the aqueous humour which is more watery, the vitreous honour is a thick, jelly-like fluid that fills the back of the eye. It also contains salt, sugar and protein. Together with the aqueous honour, help to refract light rays and produce an image on the retina. Both also help in keeping the eyeball firm and round and thus preventing its collapse.
• Retina:- The retina is the innermost layer of the eye. It contains two light-sensitive cells called the rods and the cones. The rods are sensitive to dim light while the cones are sensitive to bright light. It is on the retina that images are formed.
• Choroid:- This is a black layer at the back of the eye. It is pigmented and rich in blood vessels. It also provides food and oxygen to the adjacent parts of the eye. The choroid also helps prevent the reflection of light within the eye. It continues in front of the eye as the iris.
• Sclera:- This is the outermost part of the eye. It is a thick fibrous Connective tissue forming the white of the eye. The sclera also contains park pigments and also helps prevent reflection of light within the eye interpretation of an image, Fovea Centralis(yellow spot):- This is the most sensitive part of the retina and it is densely packed with cones. It gives the most accurate
• Optic Nerve – This nerve carries impulses to and from the brain. The point at which the nerve fibres leave the retina is called the blind spot. This spot has neither rods nor cones and is insensitive to light

IMAGE FORMATION BY THE EYE

The principle that if the light ray passes from a less dense medium to a denser medium it converges is upheld in image formation in the eye.

Light rays from an object pass through the cornea and lens and are refracted. The image formed on the retina is inverted but the optic centre in the brain corrects it as upright.

The ability of the eye to focus on objects at varying distances is called accommodation. There are certain changes that occur in the shape of the eye for it to see clearly objects at long distances and those at a near distance.

ADAPTATION FOR NEAR VISION

1. The ciliary muscles contract.

2. The suspensory ligaments relax.

3. The lens becomes thickened or more convex

4. The focal length shortens.

ADAPTATION FOR DISTANT VISION

1. The ciliary muscles relax.

2. The suspensory ligation contract

3. The lens stretches into an elongated shape.

4. The focal length is increased.

EYE DEFECTS.

(1) Short-sightedness (Myopia):

This is a defect in which patients see near objects clearly. They are unable to see the distant object clearly. 

The defect is due to the eyeball being brought to a focus before reaching the retina. The actual image the slightly elongated from front to back. Light rays from distant objects are

It is corrected by wearing a spectacle with a concave lens. This lens will lengthen the focal length as well as cause the light rays retina to be blurred or distorted to diverge slightly before entering the eye. 

Thus the image is formed on the retina. Rays from distant object short-sighted eye focus (uncorrected) 1 3 10.2: Short sight

(2) Long-sightedness ( hypermetropia):-

The patients with this effect see distant objects very clearly but cannot see near objects: clearly. The eyeball may be shorter than normal or the lens and the culinary muscle has lost their elasticity with age.

 Light rays from neat objects are brought to a focus behind the retina. Focus (uncorrected) Near object Long-sigh ted eye Fig 10.3: Long sight This defect is corrected by wailing a spectacle with a convex lens.  converge slightly before entering the eye.

The image will then be This will shorten the focal length as well as cause the light rays to on the retina

(3)Presbyopia:  This is the loss of accommodation power due to age. The lens is less elastic and near objects become difficult to bring to a focus. It is corrected by wearing bifocal lenses.

(4)Astigmatism:- cornea and the lens. It is corrected by wearing cylindrical lenses.

This is an eye defect due to irregularities in the curvature of the eyes, some eye problems in conjunctivitis  This is the inflammation of the conjunctiva and it is associated with redness of the eye. This infection is commonly called Apollo.

Causes of Conjunctivitis:-

1. Bacteria such as Staphylococcus Streptococcus and gonococcus.
2. Viruses such as Adenovirus and herpes simplex virus.
3. Allergy
4. Trauma.

Clinical Features of conjunctivitis 

• Redness of the eyes.
• Prickly or sand-like sensation in the eye,
• Lacrimation.
• Purulent eye discharge if due to bacterial infection.
• Inability to look at a bright light with the affected eye.
• The itching of the eye is due to allergy.
• investigations:

There is usually none except if due to bacteria infection and their purulent eye discharge. The swab is taken for microscopy, culture End sensitivity treatment, Broad-spectrum antibiotics are usually taken orally.

2. Analgesics.

5. Vitamin supplements.

Eye drops or ointments depending on the cause. If bacterial, Choramphenicolor Geneticin eye drops or ointments are in use, are commonly used. 

For viral, Dendric or Herpic eye drops or ointments. For allergic conjunctivitis (or vernal conjunctivitis) option, Spersallerg.

His important to note that in conjunctivitis, pain is not usual and blurring of and Steroid eye drops are commonly used, vision is not a feature.

Complication of infection

The infection may be chronic and invade the cornea

2. CATARACT

A cataract is the opacity of the lens. The cause may be congenital or acquired.

CONGENITAL CAUSE

1. Genetic as in Down’s syndrome.
2. Familial tendency
3. Infections in the uterus such as Rubella, Cytomegalovirus
4. Toxoplasmosis.

ACQUIRED CAUSES

1. Senility (old age).

2. Trauma

3. Eye infections.

4. Excessive heat.

5. Hypertension.

6. Diabetes mellitus.

CLINICAL FEATURES OF CATARACT

1. Smoke-like and cobweb-like vision.
2. Gradual loss of vision without any pain.
3. Whitish patch in the eye.

It is significant to note that cataract does not prevent light However, there may be decreased visual acuity in severe cases.

Investigations:-

There are no specific investigations done for cataracts.

Routine tests cataract

1. Haemoglobin level.

2. Urinalysis to rule out diabet?s mellitus.

3. Blood pressure measurement: not to rule out hypertension.

TREATMENT

Surgery is the only remedy. Chymotrypsin is injected into the posterior chamber is often the solution. Then the lens is removed and replaced with an artificial lens. The chemical lens and facilitates its removal.

For patients aged twenty-five years and below, the surgery done is needing and Aspiration, while Extraction is done for those above that age.

COMPLICATIONS OF CATARACT

1. Glaucoma

2. Blindness