Lecture 10 VMT 2024

Chapter 9: A Breath of Fresh Air

Quote by Gautama Buddha:

"To awaken, sit calmly, letting each breath clear your mind and open your heart."

The Respiratory System

Function: The primary function of the respiratory system is to bring oxygen from the air into the body for transport via the bloodstream to individual cells while facilitating the removal of carbon dioxide, a waste product of metabolism, from the body. This process is vital for cellular respiration, which provides energy for bodily functions.

Respiratory System Structures

The respiratory system is divided into two main tracts:

  1. Upper Respiratory Tract:

    • Comprises:

      • Nose: The entry point for air, equipped with cilia and mucous membranes that filter, warm, and moisten the incoming air.

      • Mouth: A secondary pathway for air that can also serve as an entry route when nasal breathing is inadequate.

      • Pharynx: A muscular tube that serves both respiratory and digestive systems, extending from the nasal cavity and mouth to the larynx.

      • Epiglottis: A flap of tissue that covers the trachea during swallowing to prevent food from entering the airway.

      • Larynx: Also known as the voice box, this organ contains the vocal cords and is crucial for phonation and protecting the airway.

      • Trachea: A tube that extends from the larynx to the bronchi, lined with ciliated epithelium to trap particles and pathogens.

  2. Lower Respiratory Tract:

    • Comprises the bronchial tree and lungs.

    • Bronchi: Major air passages branching from the trachea into the lungs. The primary bronchi bifurcate at the carina and further divide into secondary and tertiary bronchi.

    • Bronchioles: Smaller airways that continue to branch and lead to the alveoli. The diameter reduces progressively from bronchi to bronchioles.

    • Alveoli: Tiny air sacs at the end of bronchioles where gas exchange occurs. The alveolar walls are thin, allowing oxygen to diffuse into the blood while carbon dioxide diffuses out.

Thorax

  • The thorax contains the thoracic cavity, which houses the lungs and is lined by a double-layered membrane called the pleura.

  • Diaphragm: A dome-shaped muscle separating the thoracic cavity from the abdominal cavity; its contraction and relaxation facilitate breathing.

Breathing

Inhalation: The process of drawing air into the lungs.Exhalation: The process of expelling air from the lungs.Respiration: Refers to both the mechanical act of breathing and the biochemical processes of gas exchange.

Terms Associated with Breathing

  • Suffix -pnea relates to breathing:

    • Apnea: Temporary cessation of breathing.

    • Dyspnea: Difficulty or discomfort in breathing.

    • Bradypnea: Abnormally slow breathing rate.

    • Tachypnea: Abnormally rapid breathing rate.

  • Ox/i, ox/o, ox/y: Refer to oxygen.

  • Capn/o: Refers to carbon dioxide.

Respiratory Clinical Signs

  • Abnormal lung sounds:

    • Crepitations: Crackling sounds indicating fluid in the lungs.

    • Ronchi: Low-pitched wheezing sounds reflecting obstruction in the airways.

    • Stertor: Snoring-like sound originating above the larynx.

    • Stridor: High-pitched sound produced by blockage in the airways below the larynx.

  • Other signs:

    • Cyanosis: Bluish coloration of the skin due to low oxygen levels.

    • Epistaxis: Nosebleed, often indicating vascular issues or trauma.

    • Stenotic nares: Narrowed nostrils affecting airflow.

Respiratory Pathology

Conditions affecting the respiratory system include:

  • Aspiration: Inhalation of foreign material into the lungs.

  • Atelectasis: Collapse of lung tissue, reducing gas exchange.

  • Bronchitis: Inflammation of the bronchial tubes, often causing cough.

  • Bronchopneumonia: Infection affecting both the bronchi and the lung tissues.

  • COPD (Chronic Obstructive Pulmonary Disease): A group of progressive lung diseases that cause breathing difficulties.

  • Diaphragmatic hernia: A defect in the diaphragm allowing abdominal contents to enter the thoracic cavity.

  • Emphysema: Condition characterized by damage to the alveoli, making it difficult to breathe.

  • Hemothorax: Accumulation of blood in the pleural cavity.

  • Pneumothorax: Accumulation of air in the pleural cavity causing lung collapse.

  • Pyothorax: Accumulation of pus in the pleural cavity.

  • Laryngeal paralysis (LarPar): Dysfunction of the laryngeal muscles affecting airflow and voice.

  • Pulmonary edema vs pleural effusion: Distinction between fluid in the lung tissue and fluid in the pleural space.

  • Upper Respiratory Infection (URI): Viral or bacterial infections of the upper respiratory tract, including infectious tracheobronchitis commonly known as ‘Kennel Cough’ and feline upper respiratory complex.

Respiratory Diagnostics & Procedures

Techniques for assessing respiratory health include:

  • Bronchoscopy: Procedure to visualize the airways directly.

  • Endotracheal intubation: Inserting a tube into the trachea to maintain an open airway.

  • Endotracheal wash (ETW) vs transtracheal wash (TTW): Techniques to collect respiratory secretions for analysis.

  • Thoracic radiographs: Imaging studies to evaluate lung structure and function.

  • Thoracotomy/thoracocentesis: Surgical procedures for diagnosis or treatment of thoracic conditions.

  • Tracheostomy vs tracheotomy: Surgical procedures to create an opening in the trachea for ventilation.

  • Ventrodorsal (VD) thoracic radiograph: A specific view for assessing thoracic structures.

Respiratory Treatments

Common treatments for respiratory conditions include:

  • Antitussives: Medications to suppress coughing.

  • Bronchodilators: Drugs that relax bronchial muscles to improve airflow.

  • Coupage: A technique involving percussion on the chest to help clear mucus.

  • Mucolytics: Agents that thin and loosen mucus in the airways.

  • Nebulization: A method to deliver medication directly to the lungs in aerosol form, often used in treating asthma and other respiratory conditions.