5 Introduction to Pathophysiology

Objectives Understanding basic pathophysiology. The concept of perfusion The composition of ambient air. How changes in respiratory system function can affect ventilation. The transport of oxygen and carbon dioxide in the blood. Factors that affect cardiac output. The two ways the heart can fail resulting in decreased cardiac output.

PATHOPHYSIOLOGY

Pathophysiology Pathophysiology The study of how disease processes affect the body Allows for better identification of certain signs and symptoms to a specific course of treatment

Pathophysiology The Cell Basic unit of the human body All organs and systems Glucose is a basic nutrient for cell. Converts to energy through metabolism Oxygen Fuels metabolism Aerobic metabolism Normal glucose metabolism using oxygen Carbon dioxide is a byproduct. continued on next slide

Pathophysiology The Cell Oxygen Fuels metabolism Anaerobic metabolism Abnormal glucose metabolism without oxygen Creates increased byproducts of carbon dioxide and lactic acid Accumulated waste makes body acidic and toxic. Critical Thinking: What medical condition commonly deals with low levels of glucose? What can EMRs do to help increase the amount of glucose in the body?

Pathophysiology Fluid Balance The body is 60% water. Balance is necessary for proper cellular function. continued on next slide

Pathophysiology Fluid Balance Body adjusts fluid levels through intake and elimination of fluids. INTAKE Drinking fluids ELIMINATION Sweating Breathing Urination continued on next slide

Pathophysiology Disruption of Fluid Balance Dehydration Not enough fluid intake Excessive fluid elimination Vomiting and diarrhea continued on next slide

Pathophysiology Disruption of Fluid Balance Edema or swelling Fluid trapped in the body's tissues from illness Hands, legs and feet Lungs Injury Capillaries leak

Think About It A patient's fluid balance can easily be assessed externally. Dry mucous membranes, sunken eyes, tachycardia, and low blood pressure can indicate dehydration. Edema in the ankles and feet can give an indication of poor fluid distribution.

THE CARDIOPULMONARY SYSTEM

The Cardiopulmonary System Cardiovascular and respiratory systems work together. Respiratory system Transfers oxygen to the bloodstream Cardiovascular system Transports oxygen to the body's cells Brings carbon dioxide back to the lungs for elimination

The Cardiopulmonary System Respiratory System Structures Airway Lungs Muscles of respiration continued on next slide

The Cardiopulmonary System Respiratory System Airway Movement of air (ventilation) in and out of the chest requires a patent airway. continued on next slide

In the alveoli is where the exchange of oxygen and carbon dioxide take place. (B) The alveoli are surrounded by capillaries that bring in oxygen and venules that carry away carbon dioxide.

The Cardiopulmonary System Respiratory System Lungs Diaphragm and chest wall responsible for pressure changes that stimulate breathing Tidal volume Air moved in and out in one breath Class Activity: Evaluate the adequacy of tidal volume by assessing the rise and fall of the chest and auscultating the breath sounds of their classmates. continued on next slide

The Cardiopulmonary System Respiratory System Dysfunction Disruption of pressure Chest cavity is a closed container. Diaphragm, ribs and intercostal muscles change the size of the cavity. continued on next slide

The Cardiopulmonary System Respiratory System Compensation Brain monitors carbon dioxide levels in blood.(Medulla) Increases or decreases respiration rate and tidal volume as needed

The Cardiopulmonary System Cardiovascular System Blood Transport system of the body Blood consist of: Red blood cells: which carry O2 and carbon dioxide. White blood cells: which fight infection. Plasma: the liquid in the blood. Platelets: aid in clotting Critical Thinking: What are some ways blood volume can be increased? continued on next slide

The Cardiopulmonary System Cardiovascular System Blood vessels are pathways. Arteries Carries oxygenated blood away from the heart Veins Carries deoxygenated blood to the heart continued on next slide

The Cardiopulmonary System Cardiovascular System Blood vessels are pathways. Arterioles Feeds oxygenated blood to the capillaries Capillaries Offloads oxygen and picks up carbon dioxide, where the gas exchange between the blood and the cells takes place continued on next slide

The Cardiopulmonary System Cardiovascular System Blood vessels are pathways. Pulmonary arteries Carries deoxygenated blood from the heart to the lungs Pulmonary veins Carries oxygenated blood from the lungs to the heart continued on next slide

The Cardiopulmonary System Cardiovascular System Blood pressure Created by the beating heart to move blood around the body Talking Point: Dilation of vessels can come from sever allergic reactions/anaphylaxis, injuries to the brain and spinal cord and sepsis. Decreased volume results from major hemorrhage and. leaking of fluid through capillary walls from sepsis or other infections. Talking Point: Constriction of vessels can come from chronic smoking, drugs, and genetics. Increased fluid is associated with CHF. Results of Hypertension include stroke, heart attack, and kidney failure. continued on next slide

The Cardiopulmonary System Cardiovascular System Heart 4 chambered pump designed to move blood Stroke volume Volume of blood ejected from the heart in one contraction Cardiac output Amount of blood ejected from the heart in one minute Talking Point: Heart rate directly affects cardiac output. If the heart rate gets too fast, heart does not have enough time to fully contract and eject the right amount of blood which decreases the stroke volume and in turn decreases cardiac output. continued on next slide

The Cardiopulmonary System Cardiovascular System Heart failure Electrical failure Tachycardia Bradycardia Ventricular fibrillation Mechanical failure Trauma Squeezing of the heart muscle Loss of cardiac muscle due to cell death

Think About It The best way to assess a patient's tidal volume is to watch the chest rise and fall while counting the ventilations per minute. Hypoxia leads to cell death. Getting your patient on oxygen can delay the change to anaerobic metabolism. continued on next slide

Think About It Low blood pressure can lead to hypoxia and cell death. What are some ways that EMRs can attempt to increase pressure?

HYPOPERFUSION AND SHOCK

Hypoperfusion and Shock Delivery of oxygen and nutrients and removal of waste to every cell and organ continued on next slide

Hypoperfusion and Shock All components of the cardiopulmonary system must be functioning. Oxygen delivered all the way to the alveoli and carbon dioxide transported all the way out Enough available blood, a functioning pump, and enough pressure to make the exchange

Hypoperfusion and Shock Shock occurs when perfusion fails. Hypoperfusion Cells become hypoxic without perfusion of adequate oxygen. Switch to anaerobic metabolism Lactic acid and waste products build up. Cells eventually die. continued on next slide

Hypoperfusion and Shock Pediatric Compensation One of the leading causes of death in pediatric patients. Children compensate differently than adults. Increased heart rate is the main mechanism. continued on next slide

Hypoperfusion and Shock Pediatric Compensation Vasoconstriction allows them to maintain blood pressure with significant volume loss. Blood pressure is an unreliable factor during assessment. Higher metabolism rates burn off oxygen faster. Talking Point: Since children are better at compensating than adults, EMR may have a false sense of security in the impression of their patient. Continually reassess to recognize subtle changes in the condition of the pediatric patient.

SUMMARY

Summary Understanding pathophysiology helps you understand the basic and most important functions of the body and their critical dysfunctions. Delicate balance of fluid in the body Levels must be appropriate in the major spaces and balanced constantly to maintain life. continued on next slide

Summary Aerobic metabolism Anaerobic metabolism The normal way the body converts glucose into energy Anaerobic metabolism Not as efficient, and it creates significantly more waste product continued on next slide

Summary Perfusion Combined function of the respiratory and cardiovascular systems. All functions needed in order to deliver oxygenated blood to the cells. continued on next slide

Summary Oxygen is introduced into the body from the ambient air. Respiratory system moves air in and out of the lungs (ventilation). Inspired air pairs with circulating blood (respiration) for perfusion. Appropriate quantities ensure adequate delivery of oxygen to the cells. continued on next slide

Summary The cardiovascular system Transport mechanism for oxygen, carbon dioxide, and nutrients for the cells Requires the presence of appropriate elements of blood, pressure within the system, and a functioning pump continued on next slide

Summary Cellular metabolism Relies upon a constant supply of glucose and oxygen Normal metabolism relies upon perfusion and the successful operation of the cardiopulmonary system.