Respiratory Monitoring PDF

RESPIRATORY MONITORING By Dr Ahmed Ezeldin MDPhD-MRCP UK Lecturer of critical care medicine Faculty of medicine- Alexandria university OUTLINES CLINICAL MONITORING Pulse oximetry provides continuous, noninvasive measurement of arterial oxygen s...

RESPIRATORY MONITORING By Dr Ahmed Ezeldin MDPhD-MRCP UK Lecturer of critical care medicine Faculty of medicine- Alexandria university OUTLINES CLINICAL MONITORING Pulse oximetry provides continuous, noninvasive measurement of arterial oxygen saturation. Pulse oximetry readings should be used to provide an early warning sign, decreasing the need for blood gas measurements. Limitations of pulse oximetry are: It cannot distinguish between normal hemoglobin and methemoglobin or carboxyhemoglobin. Nail polish may affect the measurement by about 2%. Pulse oximetry can slightly underestimate arterial oxygen saturation (SaO2) in patients with darkly pigmented skin. Low perfusion states can lead to inaccurate pulse oximetry readings. Low oxyhemoglobin saturations (below  GAS EXCHANGE Interpreting arterial blood gases (ABGs) is a critical skill. As it provides valuable information about a patient's acid-base balance, oxygenation, and ventilation  SPO2 is how much Hb particles saturated with O2 (Max 100%) Hb Hb Hb Hb Hb PO2 is pressure Hb Hb Hb Hb Hb Artery OXYGENATION  Capnography The expiratory capnogram provides:- Quantitative estimation of expired CO2. NORMALRANGEofETCO2: 35-45mm/hg ETCO2LessThan35mmHg= -"Hyperventilation/Hypocapnia" ETC02GreaterThan45mmHg= -"Hypoventilation/Hypercapnia" DIFFERENCES BETWEEN OXYGENATION AND VENTILATION Oxygenation: Ventilation: Definition: Oxygenation refers Definition: Ventilation refers to the process by which oxygen to the mechanical process of is added to the bloodstream from moving air in and out of the the alveoli in the lungs. lungs (breathing) to facilitate Purpose: It ensures that oxygen gas exchange. is delivered to the tissues and Purpose: It helps remove organs for cellular metabolism. CO₂ from the blood and bring Measurement: It is typically in fresh air (O₂). measured by arterial oxygen Measurement: It is typically saturation (SpO₂) or partial pressure of oxygen (PaO₂) in assessed using arterial arterial blood. carbon dioxide tension (PaCO₂), respiratory rate, or Physiology: Oxygen diffuses tidal volume.  Central Causes (Neurological or Brain-Related): Obstructive Sleep Apnea Neuromuscular Disorders (e.g., Amyotrophic Lateral Sclerosis, Myasthenia Gravis) Muscular Causes (Weakness or Mechanical Issues): Neuromuscular Disorders (e.g., Amyotrophic Lateral Sclerosis, Myasthenia Gravis) Guillain-Barré Syndrome DISEASES OF Chest Wall Disorders (e.g., Kyphoscoliosis) Obesity Hypoventilation Syndrome IMPAIRED Bronchospasm Causes (Airway Constriction): VENTILATION Chronic Obstructive Pulmonary Disease (COPD) Asthma Cystic Fibrosis Airway Obstruction (e.g., Foreign Body Aspiration) Pneumothorax  Pneumonia Pulmonary Edema DISEASES OF Chronic Obstructive Pulmonary Disease (COPD) IMPAIRED Pulmonary Embolism (PE) OXYGENATION Acute Respiratory Distress Syndrome (ARDS) Interstitial Lung Disease (ILD) Atelectasis CHEST IMAGING 1. Information Patient Comm Verify patient details like name, date of birth, and the time/date of on the X-ray. 2. Image Quality Patholo Assessment Positioning: Ensure the patient is gies: correctly positioned (AP, PA, or Pneumoni lateral view). a: Focal or  To differentiate an AP (anteroposterior) from a PA (posteroanterior) chest X-ray, you can look for specific features based on patient positioning and X-ray technique: 1. Clavicle Positioning 4. Lung and Scapula Fields AP X-ray: AP X-ray: The clavicles are usually The lungs higher and more horizontal, may appearing above the apex of appear less the lungs. expanded due to poor The scapulae are often inspiration projected over the lung (common  ROTATION The above image shows a patient with pneumonia and abscesses. You can also see a darkened circle, which represents an abscess The cardiothoracic ratio is calculated as (MRD+MLD)/ID where MRD is the greatest perpendicular diameter from the midline (where the spine is) to the right heart border, and the MLD is the greatest perpendicular diameter from the midline to the left heart border. The ID is the internal diameter of the chest at the level of the right half of the diaphragm. The cardiothoracic ratio should be less than 0.5. DEVICES  LOBAR PNEUMONIA HEART FALUIRE PLEURAL EFFUSION  LUNG ABSCESS PNEUMOTHRAX ARDS NORMAL CT CHEST Mediastinal window Lung window MECHANICAL VENTILATION  What is Invasive Mechanical Ventilation? IMV involves delivering air (with oxygen) directly into a patient's lungs through a tube inserted into their airway. The purpose is to ensure that the lungs get enough oxygen and are able to expel carbon dioxide. It's called invasive because it requires inserting a tube either into the trachea (via the mouth or nose, called endotracheal intubation) or directly into the trachea via the neck (tracheostomy).  Why Use Invasive Mechanical Ventilation? IMV is used in conditions where the patient cannot maintain adequate breathing due to: 1. Respiratory failure: Inability to oxygenate blood or remove CO2 (e.g., in COPD exacerbation, ARDS). 2. Apnea: When the patient stops breathing (e.g., during coma, overdose). 3. Airway protection: In patients who cannot protect their own airway from aspiration (e.g., in stroke or trauma). The Role of the Ventilator: The ventilator essentially takes over or assists in: Delivering oxygen to the lungs: It supplies air with a controlled amount of oxygen (FiO2) based on the patient’s needs. Removing carbon dioxide: It ensures that CO2, a waste product of metabolism, is expelled from the body. Maintaining positive pressure: During mechanical ventilation, positive pressure is used to inflate the lungs, which is different from normal, spontaneous breathing where the diaphragm creates negative pressure to draw air into the lungs. How It Works: Ventilation cycle: The ventilator delivers air (inhalation) by pushing it into the lungs under positive pressure, and then the lungs passively exhale. Ventilator modes: There are different settings that control how much of the breathing the ventilator does for the patient, including: 1) Controlled modes (e.g., Assist-Control, AC): The ventilator does most or all of the work, delivering a set number of breaths and a fixed volume or pressure of air.