Transcript Chp8x
Pathophysiology How the body works? Our Goal Maintain adequate perfusion so the body is receiving oxygen & glucose, & continues to remove waste Cell Fundamental unit of human body Contains necessary components Energy Remove waste products Reproduce Other life essential function Cellular Metabolism Also known as Cellular Respiration Breaks down molecules of glucose to produce energy Two types of cellular metabolism Aerobic Anaerobic Cellular Metabolism Breakdowns glucose molecules to produce energy, in the presence of oxygen Glucose crosses cell membrane Broken down into pyruvic acid molecules, also known as glycolysis Releases small amounts of ATP, energy source Happens in the mitochondria Bi-product heat, CO2, H2O Aerobic Metabolism Breakdown of glucose molecules, WITHOUT the presence of oxygen Glucose crosses cell membrane, Glycolysis occurs Pyruvic acid is involved and releases ATP Without oxygen Pyruvic acid cannot go to next phase Converted into Lactic acid Anaerobic Metabolism Why do all the cells need oxygen? What are the consequences of inadequate oxygenation of the body’s tissues? What causes cells to swell and burst if hypoxia continues? If the anaerobic were to have oxygen, what would be produced instead of the lactic acid? A. B. C. D. Oxygen Carbon Dioxide ATP Nutrients Sodium has a positive charge & is found on the outside of the cell Potassium is a positive charge & is found inside the cell Flow against concentration gradient (pump) Sodium/Potassium Pump Failure Failure of the Sodium/Potassium Pump can result in: A.Cellular damage, swelling, & rupture B. Accumulation of acidic wastes C.Excess amounts of sodium outside the cell D.Large amounts of potassium inside the cell Brain Break Rub-a-Dub 1. Stand up. 2. Pat your head with your right hand. 3. Rub your stomach with your left hand. 4. Switch hands Components Necessary for Adequate Perfusion Composition of ambient air Patent airway Mechanics of ventilation Regulation of ventilation Ventilation/perfusion ratio Transport of oxygen and carbon dioxide by the blood Blood volume Pump function of the myocardium Systemic vascular resistance Microcirculation Blood pressure Perfusion is best described as: A. B. C. D. Availability of oxygen to the lungs for placement into the blood An adequate amount of white blood cells for delivery of oxygen to the cells Delivery of essential products and nutrients to the cell for use. Exchange of oxygen and carbon dioxide between the lungs and blood Questions What is hypoprofusion also known as? Shock B. Hypovolemia C. V/Q mismatch D. Respiratory Depression A. Composition of Ambient Air Amount of oxygen in air we breathe 21% Lower oxygen concentration-lower amount of oxygen in tissues Fi02 –fraction of inspired oxygen FDO2—fraction of inspired oxygen Composition of Ambient Air Question: How does the content of gases in the ambient air affect the oxygenation status of the patient? FDO2 Same as FiO2 but with patients on ventilators Toxic Gases: Displace amount of oxygen in air Other Gases: Disrupt ability for cell to carry oxygen Brain Break Friend Connect 1. Stand up. 2. Partner up with a friend or someone you don’t know. 3. Take 1 minute to review your notes without talking. I will give you 1 minute to discuss what you have learned so far without your partner talking. I will then give you 1 more minute to review your notes Then second person will talk about what they have learned without repeating 1st person. 1st person does not speak. Respiratory Review Patency of Airway Active inhalation Passive exhalation Nasopharynx Obstructed by blood, secretions, vomitus, tissue swelling, bone fragments, or other substances. Usually not a major airway if problem the oropharynx remains clear. May cause aspiration if not taken care of May be used as an alternate airway of oropharynx blocked Epiglottis • a flap of cartilaginous tissue that covers the opening of the larynx during swallowing. • If the epiglottis is injured and swells or becomes inflamed from infection, it can occlude the airway • A jaw-thrust or chin-lift maneuver is designed to lift the epiglottis clear of the glottic opening. • If obstruction caused by swelling or inflammation, advanced airway management is likely required Larynx Trachea & Bronchi A young patient is experiencing epiglottitis. He is working hard to breathe, has stridorous respirations & extremely hypoxic. His skin is cyanotic, and pulse rapid but strong. Why is this patient showing these symptoms? Respiratory Continued Lets Review! Alveolar Respiration Cellular Respiration Respiration Accessory Muscles of Inhalation Very energy intensive Will compound respiratory problems https://www.youtube.com/ watch?v=Hv68EQ3tCBI Airway compliance/resistance Compliance-how far the lungs will stretch, distend, and expand Airway resistance-how easy does the air get to alveoli. Pleural spacing A potential space between the pleura Maintains negative pressure Occluding any open wounds to the chest is done very early in the primary assessment How pleural spacing works Injury to the lung tissue will draw air into the pleural space With each breath the thorax increase in size Every time we breath in it increases its volume and collapses the lungs Minute Volume • In an average adult, tidal volume (VT) is ~ 500 mL and frequency is ~ 12 breaths per minute • MV = 500mL x 12/min = 6,000 mL/min or 6 L/min Minute Volume Minute Ventilation = Tidal Volume (VT) x Frequency (f/min) Tidal Volume The volume of air breathed in with each individual breath. Questions: How do patients compensate for a condition that decreases tidal volume? What is considered to be an “average” tidal volume for an adult A. B. C. D. 200 ml 1L 500 ml 1.5 L Minute Ventilation Summarized A decrease in tidal volume will decrease the minute ventilation. A decrease in frequency of ventilation will decrease minute ventilation. A decrease in minute ventilation will reduce the amount of air available for gas exchange in the alveoli. A decrease in minute ventilation can lead to cellular hypoxia. The ensure adequate ventilation, the patient must have both an adequate tidal volume and an adequate rate of ventilation. Dead Air Space Anatomical collides. Where So area in the respiratory tract where air no gas exchange occurs. the air moving in and out of exchange is wasted. Alveolar Ventilation Key Points of Alveolar Ventilation Faster breathing Dead air spaces fill regardless of volume of air breathed in and amount made available to alveoli. Assessing the tidal volume is as important as assessing the ventilatory rate. Discussion Question If a patient is hyperventilating (breathing too fast) why is he/she not getting enough oxygen? Inadequate ventilation and cellular hypoxia can occur from: A low tidal volume. A ventilatory rate that is too slow. A ventilatory rate that is too fast. Regulation of ventilation Primary control in brainstem Regular ventilation Breathing mostly involuntary process Controlled by the autonomic nervous system Receptors in body constantly measure Oxygen, carbon dioxide, hydrogen ions, and send signals to brain to adjust rate & depth of respiration Voluntary control Hold your breath, alter breathing pattern during talking, laughing, and singing. Involuntary control Respiratory center located in brain stem Chemoreceptor Specialized receptors that monitor the pH, carbon dioxide, and oxygen levels in arterial blood. Central chemoreceptor Located near respiratory in medulla, most sensitive to carbon dioxide and changes is pH Peripheral chemoreceptor Located near aortic arch and carotid bodies in neck, some what sensitive to carbon dioxide and Ph, mostly sensitive to the level of oxygen in arterial blood General Rule The greater amount of CO2 in the blood, the greater amount of acid The lesser amount of CO2 in the blood, the lesser amount of acide Central chemoreceptor's summarized An in arterial CO2 will hydrogen ions in CSF, which will rate & depth of respirations A in arterial CO2 will hydrogen ions in CSF, which will rate & depth of respirations Peripheral Summarization A arterial O2 will respirations rate & depth of Which one of the following is the primary stimulus to breathe in normal human beings? A. B. C. D. level of CO2 in the body Amount of nitrogen in air Amount of oxygen required by the body Level of oxygen in the body Hypoxic drive A persons rate and depth of breathing regulated primarily by the amount of carbon dioxide in blood this is referred to as hypercapnic or hypercarbic drive In patients with COPD they have a tendency to retain carbon dioxide in arterial blood as a result of their poor gas exchange So…. In a normal person it’s the carbon dioxide in the blood that triggers the urge to breath. In a person compromised with gas exchange (COPD, chronic bronchitis) the body gets used to the high levels of carbon dioxide & so no urge to breath. The lowered oxygen level that triggers the urge to breath- hypoxic drive Lung Receptors Irritant receptors Found in airways Stretch receptors Found in smooth muscle of airway Sensitive gases, aerosols, & particles Stimulate decrease in rate & volume of ventilation when overstretched J-receptors Found in capillaries Sensitive to increase in pressure of capillary Stimulate shallow, rapid respirations Respiratory Centers Ventral respiratory group (VRG) Has inspiratory & expiratory neurons Stimulate external intercostal muscles & diaphram Dorsal respiratory group (DRG) Initiates basic rhythm of breathing Pontine respiratory center Sends signals to VRG to turn off inhalation Ventilation/Perfusion Ratio Ratio between amount of air in alveoli and perfusion in capillaries https://www.youtube.com/ watch?v=RJ-H8_0-8wk Ventilatory Disturbance Less oxygenated air available Can lead to hypoxia Blood pressure not affected Pressure Imbalances What’s the point? The whole point of breathing is to get gas exchange to occur between the blood and the air, so that oxygen can get into our tissues. Without the oxygen, our tissues would die. https://www.youtube.com/watch?v=hK ACkc5aUTE&list=PLQ_IRFkDInv9INje6o21 PxV1pIpHV_QrT Perfusion Disturbance Tissues can become hypoxic due to low red blood cells Carbon Dioxide/Oxygen Exchange Oxygen and carbon dioxide exchange takes place in between the lungs and blood. What Happens? Most of the oxygen diffuses into the blood and at the same time, carbon dioxide diffuses out. What is an erythrocyte? A red blood cell that is typically a biconcave disc without a nucleus. Erythrocytes contain the pigment hemoglobin, which imparts the red color to blood, and transport oxygen and carbon dioxide to and from the tissues. What Happens? 97% of the oxygen is now carried by the erythrocytes, in which it combines with the hemoglobin. Hemoglobin & Oxy-hemoglobin Hemoglobin is purple colored. Oxy-hemoglobin is bright red colored. During circulation, the oxy-hemoglobin reaches the tissues, breaks up releasing most of its oxygen, and turns purple as hemoglobin. This makes the blood act as an efficient oxygen carrier. Blood Volume Determinant perfusion. of adequate blood pressure and Composition of Blood Red Blood Cells: carry oxygen to body cells and carry carbon dioxide away from cells White Blood Cells: part of immune system and help to fight infections Platelets: stops bleed, clots wounds. Plasma: liquid part of blood that carries blood cells and nutrients to tissues Distribution of Blood Cardiovascular system. Hydrostatic & Oscontic Pressure Pressure summarized hydrostatic pressure will push fluid out of capillary & create edema hydrostatic pressure will push less fluid out of vessel oncotic pressure will draw fluid into vessel creating volume overload oncotic pressure will not adverse hydrostatic pressure creating less vascular volume & promote edema Cardiac Output The volume of blood ejected from the left ventricle in one minute. A drop of blood ejected from left ventricle will return in one minute. # beats per minute Automaticity Nervous System Influence Sympathetic SNS SNS HR HR Parasympathetic PSNS HR PSNS HR Preload Resting phase of cardiac cycle Starling’s law Muscle fibers stretching during contracton Afterload Resistance in aorta cause by contraction of left ventricle Systemic Vascular resistance What's it do? 1. 2. 3. 4. The vessel Diameter controls the resistance. As the vessel gets smaller the resistance increases. An increase in resistance will increase the diastolic pressure. A decrease in resistance will decrease the diastolic pressure. Patient Scenario A patient whose vessels are dilating (getting bigger or vasodilation). His diastolic blood pressure would decrease because there isn’t enough blood in the vessels to build up pressure. Why? Pulse Pressure Difference between the systolic & diastolic BP Narrow Pulse Pressure= systolic diastolic Shock Widen Pulse Pressure= Head injury systolic diastolic Systemic vascular resistance Diastolic blood pressure Systemic vascular resistance Diastolic blood pressure Systolic & Diastolic Systolic- the force against the walls of the arteries when the left ventricle contracts. Diastolic- the force against the walls of the arteries when the left ventricle is at rest, or between contractions. What does that mean? The Systolic blood pressure measures the effectiveness of the pumping function of the left ventricle. The Diastolic blood pressure measures the resistance in the arteries between contractions. BP in a nut shell BP will affect perfusion BP will BP will cellular perfusion cellular perfusion