Pneumonia 1

Pneumonia - Part 1

Overview

• This video is an NCLEX review focusing on pneumonia as a part of a broader series on respiratory disorders.

• The video is divided into two parts, with this being part one, covering:

  • Pathophysiology of pneumonia

  • Definition of pneumonia

  • Risk factors for pneumonia

  • Diagnosis of pneumonia

  • Signs and symptoms of pneumonia

Definition of Pneumonia

• Pneumonia is defined as:

  • A lower respiratory tract infection that causes inflammation of the alveoli sacs.

• The alveoli sacs are critical for gas exchange in the lungs:

  • The diagram shows purple areas resembling grape sacs where gas exchange occurs.

  • Alveoli inflate and deflate, allowing carbon dioxide to be exhaled and oxygen to be inhaled and transported through the body.

Key Players in Pneumonia

• Pneumonia is primarily caused by:

  • Germs: This includes bacteria, viruses, or fungi (though fungal pneumonia is rare).

  • Inflammation of the alveoli leads to pneumonia symptoms.

• Lung Parenchyma Components: (Trio for Gas Exchange)

  • Alveoli

  • Alveolar ducts

  • Bronchioles

Normal Gas Exchange Process

1. Oxygen Inhalation Process:

   • Oxygen enters through the upper respiratory system (nose, sinuses, larynx).

   • It travels down the trachea, which splits at the carina into right and left bronchi.

   • Oxygen reaches the lungs via the hilum, where the pulmonary artery (carrying unoxygenated blood) and pulmonary vein (carrying oxygenated blood) enter the lungs.

   • These branches lead to:

     • Secondary bronchi

     • Tertiary bronchi

     • Bronchioles

     • Alveolar ducts

     • Alveolar sacs

2. Gas Exchange Mechanism:

   • Alveolar sacs are enveloped by capillaries from pulmonary arteries and veins.

     • The pulmonary artery brings unoxygenated blood.

     • Oxygen diffuses through the capillary wall into red blood cells, while carbon dioxide is expelled into the alveoli for exhalation.

   • This continuous process helps maintain oxygen delivery throughout the body.

Pathophysiology of Pneumonia

• Pneumonia occurs when the respiratory system is unable to combat invading germs.

• Inflammation of the alveoli leads to:

  • Accumulation of fluid and white blood cells in the alveoli.

  • Increased difficulty in gas exchange due to congestion and fluid.

  • Results in hypoxemia (low oxygen levels in the blood) and may lead to respiratory acidosis due to carbon dioxide retention.

Risk Factors for Developing Pneumonia

• Prior Infections:

  • Prior infections like influenza or a cold weaken the immune system, increasing pneumonia risk.

• Weak Immune System:

  • Populations at risk include:

  • Infants

  • Elderly- main cause

  • Ventilator associated pneumonia-repositioning every 2hour, best indicator is positive sputum culture not xray or blood test

  • Individuals with HIV or on immunosuppressant medications.

• Immobility:

  • Patients who are bed-ridden or have conditions like strokes or dementia are at higher risk, especially from aspiration pneumonia.

• Underlying Lung Issues:

  • Chronic Obstructive Pulmonary Disease (COPD) and recent surgery increase risk.

• Post operative patient- encourage

Respiratory Acidosis in Pneumonia

• Understanding Respiratory Acidosis:

  • Caused by the inability of alveoli to expel carbon dioxide due to inflammation and fluid buildup.

  • Results in:

  • Low blood oxygen (hypoxemia).

  • Retention of carbon dioxide leading to acidity in the blood.

• Key Arterial Blood Gas (ABG) Values:

  • PaO2: Typically less than 90 mmHg.

  • Blood pH: Less than 7.35 (indicative of acidosis).

  • PaCO2: Greater than 45 mmHg (due to carbon dioxide retention).

  • Bicarbonate (HCO3-): May be greater than 26 mEq/L as the kidneys attempt to compensate for acidity.

Pathogens Causing Pneumonia

• Bacteria, viruses, and fungi can all lead to pneumonia, necessitating understanding of each pathogen's role and implications for treatment.