THE RESPIRATORY SYSTEM

DEFINITIONS

SINUSITIS- Inflammation of the lining of the paranasal sinuses, the Maxillary (side pocket of the nasal cavity) and the Frontal (above the eyes on either side of the forehead)

RHINITIS-Inflammation of the lining of the nasal cavity or Rhinarium

EPISTAXIS- Bleeding from the nose, either unilateral (one nostril) or bilateral (both nostrils).

LARYNGITIS- Inflammation of the laryngeal mucosa

PHARYNGITIS- Inflammation of the lining of the pharynx, (2 divisions- Oropharynx & Nasopharynx).

TONSILLITIS- Inflammation (usually accompanied by enlargement) of the tonsils. Rare as an isolated inflammatory reaction.

TRACHEITIS- Inflammation of the tracheal lining.

BRONCHITIS- Inflammation of the Bronchi / larger airways. (Inflammation of the smaller bronchioles is called bronchiolitis ) (surprise!)

PLEURISY- Inflammation of the pleura (visceral next to the lungs, parietal lining the thoracic wall.)

PNEUMONIA- Inflammation of the lungs, although the use of this term is usually confined to the accumulation of pus / exudate seen in the alveoli.

AIRWAY DISEASE

Sinusitis on its own is unusual, normally it precedes or follows problems in the nasal chamber, as access to the sinuses is via OSTIA or holes which communicate with the nose.

Causes of Rhinitis

1) Bacterial and Viral infections- Feline upper resp disease, canine viruses such as Parainfluenza. Serous, then mucoid then purulent discharges. Chronic hyperplastic rhinitis can complicate, particularly in cats.

2) Foreign bodies. Seeds enter from the front ( usually in dogs), and grass is regurgitated from the oesophagus into the pharynx (usually cats). Serous then purulent discharge.

3)Polyps. Feline problem, these grow from the opening of the eustachian tube, and extend into the pharynx. Young cats. Serous / purulent. Noisy!

4)Aspergillosis. Long nosed (doliocephalic) dogs. ++rare in cats. Sneezing and mucopurulent then bloody discharge. Unilateral but destructive so can become bilateral.

5) Allergic rhinitis. Serous and sneezing. Related to Feline Asthma Syndrome in cats.

6) Neoplasia. Aged dogs, rare in cats. Unilateral serous then purulent then bleeding then bilateral as tumour enlarges. Severe occlusion of the airway on the affected side(s).

Other causes of epistaxis-

1) Clotting problems - Inherited coagulopathies, Autoimmune platelet deficiencies, Warfarin and anticoagulant poisonings.

2) Trauma.

3) Occasionally, tooth root abscesses.

Brachycephalic Upper Airway Syndrome (BUAS)

Multiple anatomical deformities

Stenotic nares | Hyperplastic soft palate | Laryngeal malformation | Everted laryngeal ventricles | Hypoplastic trachea

Coughing

"An airway reflex initiated by mechanical (pressure) or chemical stimuli."

Cough receptors are in the upper airways, there are none in the lower airways and alveoli. The purpose of the cough is to remove intra-airway material, but this reflex is only activated when the stimulus reaches the upper airways. In the case of pneumonia, therefore, serious disease may precede coughing.

Coughs are rarely productive in the dog and cat, but owners often mistakenly report productive retching of saliva as something brought up from the lungs.

Types of cough-

-Harsh / hacking / dry. Large airway, usually a tracheitis or tracheobronchitis (e.g. Kennel Cough), but can be a heart cough ( covered in the circulatory system), so always worth asking about exercise tolerance.

-Honking. Usually tracheal collapse (small breeds) occasionally a foreign body.

-Soft mild cough. Usually lower airways, so can be the most serious.

Causes of cough-

- Tonsillitis, pharyngitis, laryngitis, laryngeal paralysis, neoplasia (Also see choking, dysphagia if these sites are involved).

-Tracheal collapse, hypoplastic trachea, tracheal stenosis or neoplasia, tracheal compression (heart enlargement, tumours), tracheobronchitis, bronchitis, bronchiectasis, lungwor, foreign bodies, asthma.

-Cardiac disease

-Mediastinal disease (tumours, inflammation)

-Lung parenchyma disease (pneumonia, oedema, abscess, haemorrhage, neoplasia).

-Pleurisy. may be dry (inflammatory) or effusive-chyle, haemorrhage, exudate, pus.

Treatment of coughing

Identify and treat the primary cause if possible.

Nursing- Warmed, moistened air, Vapour inhalation, Human cough remedies ( e. g. benylin, honey and lemon, if tolerated.)

Drugs- Mucolytics- bromhexine (Bisolvon)

- Suppressants- If a non-productive, exhausting cough. Butorphanol (Torbutrol), codeine, steroids.

ACUTE RESPIRATORY FAILURE

Defined as failure of gas exchange in the lungs, mainly failure to take up O2, but also failure to lose CO2.

HYPOXIA AND CYANOSIS

Threr are 2 ways to look at what is going on-

1) What is the mechanism by which oxygen exchange is failing?

-Poor oxygen intake (particularly a problem in anaesthesia)

-Poor tidal flow (rate, volume, dead space)

-Alveolar hypoxia ( Oxygen not getting into the alveoli)

-Haemoglobin hypoxia (Anaemia, poisoning e.g. carbon monoxide)

-Circulatory hypoxia ( Poor cardiac output )

-Toxic hypoxia ( Cyanide, alkalosis)

-Tissue demand hypoxia ( Extreme levels of muscle activity)

2) What causes lead to the above problems? (A long list!)

-Trauma (Pneumothorax, haemothorax, chylothorax, ruptured diaphragm, miscellaneous airway haemorrhage and damage)

-Foreign bodies and tumours

-Non traumatic intra pulmonary haemorrhage ( Warfarin, coagulopathies.)

-Pulmonary oedema

-Other effusions ( neoplastic, pyothorax)

-Anaesthesia

-Increased abdominal pressure ( pregnancy, gastric torsion)

- Poisons ( paraquat )

RECOGNISE AND REACT:

1)Cyanosis

Is not obvious at the mucous membranes until Hb oxygen saturation is below 80% so use a pulse oximeter if available, and you suspect cyanosis .

2) Breathing patterns - Hyperpnoea = Exagerrated breathing movements

Tachypnoea= Rapid respiration

Dyspnoea = Abnormal respiratory pattern

Orthopnoea = Animal assumes sternal recumbency with elbow abducted in order to breath.

3) Cardiovascular effects- Tachycardia, arhythmias.

Remember ABC- Airway, breathing, circulation.

Establish and maintain an airway

1) Remove obstructions in the upper airway - suction for liquids, forceps or Heimlich for FB’s.

2) Oxygen supply. Many ways to do this, no matter what the original cause of respiratory failure.

-Mask (can also be used with an AMBU bag)

-Intranasal cannula

-Needle into trachea

-Urinary catheter into trachea, either per os or via tracheotomy

-TRACHEOSTOMY

Procedure for tracheostomy

a/ Animal in dorsal recumbency with head extended

b/ Full surgical prep of neck if poss.

c/ Midline incision just below the cricoid, then divide sternohyoideus muscles.

d/ Either incise between the 2nd and 3rd or 3rd and 4th tracheal rings and insert tube OR cut a square, hinged flap out of two rings to allow passage.

e/Tie or suture in place.

f/ Clean every 2-4 hours with sterile saline.

Other nursing procedures for Airway disease

Supply humidified air; turn recumbent patients to prevent hypostatic pneumonia; use coupage for secretions.

Draining pleural effusions

Thoracocentesis is used to remove / examine fluids from the pleural cavity as a "one-off". This is accomplished with a needle + syringe, separated by a 3-way tap, and a giving set to allow for patient movement.. Th 6th to 8th intercostal spaces are used, either side depending on the clinical examination.

If longer term drainage is needed, a chest drain must be used. Local anaesthetic is infiltrated in the skin at space 9, then in the intercostal muscles at space 6/8. The drain is passed through the skin at 9 then advanced forwards and through into the chest at 6/8. It is sutured in place using a "finger trap".

STERILE PREP MUST BE USED FOR BOTH OF THESE PROCEDURES.

AIR TIGHT CLOSURE OF THE END OF THE DRAIN MUST BE MAINTAINED AT ALL TIMES.

Suction or evacuation of the effusion is generally via a syringe (intermittent) or water bottle or Heimlich valve (constant).

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