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33 Cards in this Set
- Front
- Back
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What is COPD? |
- Characterised by impaired lung ventilation leading to lack of oxygen and build up of CO2 thus decrease in PH - 5th biggest killer in Uk - 3000,000 with it, only 900,000 diagnosed correctly -Increase 3x faster in women thought to be due to increase in smoking incidence in women |
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What Diseases Fall Under the Term COPD? |
Chronic Bronchitis: Primarily caused by smoking |
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What are the Three Mechanisms of Airway Obstruction? |
1. Lumen partially occluded by excessive secretions e.g. mucus in chronic bronchitis leading to complete blockage of terminal airways 2. Issues in the walls of the airways e.g. Hypertrophy of mucus glands in chronic bronchitis / inflammation 3. Destruction of parenchyma outside the airways leading to a loss of elasticity and a narrowing of the airways e.g. In emphysema |
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What are the two Types of COPD? |
Type A: Pink puffer |
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What are the Clinical Features of Type A COPD? |
- Mid 50s - Shortness of breath - Weight loss - Over expanded chest - Narrowing of peripheral blood vessels |
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What are the Clinical Features of Type B COPD? |
- Mid 50s - Chronic cough and expectoration - Acute exacerbations with purulent sputum - Stocky build -Cyanosis |
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What is Emphysema? |
- Extensive damage to terminal airways leading to merging of air sacs - trapping air leading to a lack of ventillation / elasticity
- Leads to air not being properly expelled |
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What are the Characteristics of Bronchitis? |
- Excessive mucus production - Hypertrophy of mucus glands in large bronchi - Chronic inflammation in small airways - Narrowing of the small airways - Semi-solid mucus plugs occlude the small bronchi -Leading cause is smoking |
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What is the Importance of Blood Gasses, PH and Electrolytes? |
-High priority for accurate measurements as they are a vital physiological process of acute care patients - Important clinical decisions made based on these measurements - Lab plays key role in assessment of acid base disorders |
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What Affect does Fluctuations in PH Have? |
- Structure of biological molecules directly related to function - PH fluctuations can affect the molecular integrity e.g. Enzymes have an optimal PH, ionisation of AA leads to disrruptions in binding ability, covalent interactions holding structures together undergo conformational changes. - Can affect the interactions that cells have with the outside e.g. Permeability - Leads to CO2 accumulation and the formation of carbonic acid |
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Why do PH Changes have such Drastic Effects? |
A single point change in PH leads to a 10 fold difference |
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What are the two Types of Acid-Base Disorders? |
Acidosis: Causes CNS depression, confusion, disorientation and respiratory failure. Alkalosis: Hyperexcitability of neurones, twitches, paralysis of respiratory muscles. |
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What is the Role of Hydrogen Ion Homeostasis in Relation to Respiratory Processes? |
The formation of hydrogen ions leads to: |
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What are the Main Buffering Systems in the Body? |
In the body: Phosphate and Haemoglobin In cell culture medium: Bicarbonate designed to react with 5% CO2 production |
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What happens when the Extent of a Buffer is Exceeded? |
- Can only rely on the lungs and the kidneys to rebalance = COMPENSATION Lungs: H+ ions detect a change in PH and increase / decrease respiration to increase / decrease amount of CO2 expelled Kidneys: Increase / decrease excretion - however this is much slower |
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What Happens when H+ Ions are Increased / Decreased? |
Increased: PH is too low leading to acidosis Decrease: PH is too high leading to alkalosis |
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How is PH Maintained? |
Buffering Systems: Major normal physiological mechanisms Renal and respiratory regulation |
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What is the Role of Type A Intercellated Cells in Acidosis? |
Secrete acid via an apical H+ ATPase and H+ / k+ exchanger in the form of H+ ions and reabsorbs bicarbonate. |
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What is the Role of Type B Intercellated Cells in Alkalosis? |
Secrete bicarbonate and reabsorb acid |
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What are the 4 Subcategories of Acid-Base Disorders? |
1. Respiratory acidosis |
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How does Renal Compensation Work? |
- Main compensation mechanism in respiratory acidosis / alkalosis as the lungs are impaired - can't compensate for lack of ventillation - Works by altering bicarbonate reabsorption and acid excretion |
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How does Respiratory Compensation Work? |
- Main Compensation mechanism in renal acidosis / alkalosis - Works by hypo/hyperventillation |
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What Factors Affect Respiration Rate and Hence Respiratory Acid-Base Status? |
- PH changed exerted by receptors in the aortic arch, carotid body and brain stem - Increase in H+ ions leads to a decrease in PH and an increase in respiration - Decrease in H+ ions leads to an increase in PH and a decrease in respiration |
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What are the Causes of Metabolic Acidosis? |
-Example: Diabetes Mellitus and Lactic Acidosis - Increased H+ ion formation - Acid ingestion - Decrease of H+ ion excretion - Loss of bicarbonate found in GI fluids |
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What are the Compensation Mechanisms of Metabolic Acidosis? |
- Hyperventillation - If acidosis is not corrected a new steady state is achieved involving: Increased H+, decreased bicarbonate and decreased PC02 |
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How is Metabollic Acidosis Corrected? |
- Reversal of the underlying cause - Removal of the poison |
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What are the Causes of Respiratory Acidosis? |
Increased PCO2 due to: - Airway obstruction - Depression of the respiratory centre (sedatives / anasthetics) - Neuromuscular (polio, MND and neurotoxins) - Pulmonary disease ( Pneumonia) |
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How is Respiratory Acidosis Corrected? |
Acute: Oxygen Therapy Chronic: Improved ventilaion via physiotherapy, bronchodilation and antibiotics |
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What are the Causes of Metabolic Alkalosis? |
Primary increase in HCO3 caused by: - Massive ingestion of bicarbonate - Loss of acid via gastric acid loss from vommiting - Renal causes such as Cushings syndrome, drugs and mineral corticoid excess - Administration of alkali |
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What are the Causes of Respiratory Alkalosis? |
Fall in PCO2 caused by: - Hypoxia due to anaemia / altitude / pulmonary disease - Increased respiration due to stimulants, cerebal disturbances and hyperventillation |
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How is Respiratory Alkalosis Corrected? |
Correction is directed at the underlying cause |
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What Laboratory Assessments can be used for Acid-Base Disorders? |
- Arterial blood to analyse blood gasses - Anticoagulation with Heparin |
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How can the Accuracy of Measurements be Ensured? |
- Exclusion of air from the syringe - Analysis must be performed immediately as blood gasses are more prone to artifacts - Standardisation of methods - Clean probe / analyser used as proteins can stick to the metal causing a decrease in quality - Control temperature as an increase in temp leads to a decrease in the capacity to hold gas as it boils off |
