B260: THE SCIENCE AND TECHNOLOGY OF NURSING Gas Exchange Vema Sweitzer, MN, RN 1

Gas exchange/Oxygenation Oxygenation can be defined as the mechanisms that facilitate or impair the body’s ability to supply oxygen to all cells of the body. The function of the respiratory system is to obtain oxygen from atmospheric air, to transport this air through the respiratory tract into the alveoli, and ultimately to diffuse oxygen into the body that carries oxygen to all the cells of the body. 2

Pulmonary System Ventilation The process of moving gases into and out of the lungs Perfusion The ability of the cardiovascular system to pump oxygenated blood to the tissues and return deoxygenated blood to the lungs 3

Pulmonary System Diffusion: Exchange of respiratory gases in the alveoli and capillaries. The thickness of the alveolar capillary membrane affects the rate of diffusion. Oxygen transport = Lungs + cardiovascular (CV) system Hemoglobin carries O 2 and CO 2 Carbon dioxide transport 4

Cardiovascular Physiology Cardiopulmonary physiology involves delivery of deoxygenated blood (blood high in carbon dioxide and low in oxygen) to the right side of the heart and then to the lungs, where it is oxygenated. Oxygenated blood (blood high in oxygen and low in carbon dioxide) then travels from the lungs to the left side of the heart and the tissues.

Cardiovascular Physiology Myocardial pump Two atria and two ventricles As the myocardium stretches, the strength of the subsequent contraction increases (Starling’s law). Myocardial blood flow Unidirectional through four valves S 1 : mitral and tricuspid close S 2 : aortic and pulmonic close Coronary artery circulation Coronary arteries supply the myocardium with nutrients and remove wastes. Systemic circulation Arteries and veins deliver nutrients and oxygen and remove waste products.

Blood Flow Regulation Cardiac output Amount of blood ejected from the left ventricle each minute Stroke volume Amount of blood ejected from the left ventricle with each contraction Cardiac output (CO) = Stroke volume (SV) × Heart rate (HR) Preload End-diastolic pressure Afterload Resistance to left ventricular ejection

Lifestyle Factors Nutrition Cardioprotective nutrition = Diets rich in fiber; whole grains; fresh fruits and vegetables; nuts; antioxidants; lean meats; and omega-3 fatty acids. Exercise People who exercise for 30 to 60 minutes daily have a lower pulse rate and blood pressure, decreased cholesterol level, increased blood flow, and greater oxygen extraction by working muscles. 8

Lifestyle Risk Factors Smoking Associated with heart disease, COPD, and lung cancer The risk of lung cancer is 10 times greater for a person who smokes than for a nonsmoker. Substance abuse Excessive use of alcohol and other drugs impairs tissue oxygenation. Stress A continuous state of stress or severe anxiety increases the metabolic rate and oxygen demand of the body. 9

Environmental Factors The incidence of pulmonary disease is higher in smoggy, urban areas than in rural areas. A patient’s workplace sometimes increases the risk for pulmonary disease. Coccidioidomycosis Asbestosis 10

Pneumonia Pneumonia is an acute inflammation of the lung that is most frequently caused by a microorganism. Fluid and exudate in the alveoli. 11

Nursing Diagnosis Impaired gas exchange r/t fluid and exudate accumulation in the alveoli AEB wheezing. Outcome Patient will have a O2 sat of %, clear breath sounds and temperature between

Plan of Care (POC) Assessments or what do we see Interventions or what we do Teaching or what do we teach 13

Oxygenation Safety Oxygen must be prescribed and adjusted only with a HCP’s order. Determine that all electrical equipment in the room is functioning correctly and properly grounded. An electrical spark in the presence of oxygen can result in a serious fire. Check the oxygen level of portable tanks before transporting a patient to ensure there is enough oxygen in the tank. 14

Oxygenation Safety Secure oxygen cylinders so they do not fall over. Store them upright and either chained or secured in appropriate holders. 15

Suctioning Suctioning is necessary when patients are unable to clear respiratory secretions from the airways by coughing or other less invasive procedures. 16

How to Suction a Tracheostomy 17

How to Suction a Tracheostomy 18

Emergency Patient is having Acute Dyspnea Acute dyspnea for patient with tracheostomy is most commonly caused by partial or complete blockage of the tracheostomy tube retained secretions. To unblock the tracheostomy tube: 1. ASK THE PATIENT TO COUGH: A strong cough may be all that is needed to expectorate secretions. 2. REMOVE THE INNER CANNULA: If there are secretions stuck in the tube, they will automatically be removed when you take out the inner cannula. The outer tube – which does not have secretions in it – will allow the patient to breath freely. Clean and replace the inner cannula. 3. SUCTION: If coughing or removing the inner cannula do not work, it may be that secretions are lower down the patients airway. Use the suction machine to remove secretions. 4. If these measures fail – commence low concentration oxygen therapy via a tracheostomy mask, and call for medical assistance. 19

Suctioning (Skill 40-1) Key points: Use sterile procedure Suction set on continuous suction of mm Hg Insert catheter, suction intermittently seconds and slowly rotate and withdraw Monitor patient: Risk for hypoxia Hypotension Arrhythmias Trauma Irritation Nursing Diagnosis: Ineffective airway clearance r/t retention of secretions and poor cough effort. 20

Oxygenation: Chest Tubes Chest tubes A catheter placed through the thorax to remove air and fluids from the pleural space Purpose To remove air and fluids from the pleural space To prevent air or fluid from reentering the pleural space To re-establish normal intra-pleural and intra- pulmonary pressures 21

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