acute 1.docx

Key Lung volumes E.g., Vt, VC, ect. ----------------------------------- Know description and normal ranges +-----------------------+-----------------------+-----------------------+ | **Volume** | **Description** | **Normal Range** | +=======================+==================...

Key Lung volumes E.g., Vt, VC, ect. ----------------------------------- Know description and normal ranges +-----------------------+-----------------------+-----------------------+ | **Volume** | **Description** | **Normal Range** | +=======================+=======================+=======================+ | Total lung capacity | Maximum volume of air | Depends on age, sex | | | your lungs can hold | and height | | | after a full | | | | inhalation | 5-6L | +-----------------------+-----------------------+-----------------------+ | *Tidal Volume* | Volume of air you | 500mL | | | breathe in and out | | | | during a normal | | | | breath | | +-----------------------+-----------------------+-----------------------+ | *Vital Capacity* | Maximum amount of air | 4L | | | you can exhale after | | | | a deep inhalation | | +-----------------------+-----------------------+-----------------------+ | *Residual Volume* | Volume of air | 1L | | | remaining in your | | | | lungs after a | | | | forceful exhalation | | +-----------------------+-----------------------+-----------------------+ | *Functional Residual | Volume of air left in | 2.5L | | Capacity* | your lungs after a | | | | normal exhalation | | +-----------------------+-----------------------+-----------------------+ | *Expiratory Reserve | Additional air you | 1000 mL | | Volume* | can forcefully exhale | | | | after a normal | | | | exhalation | | +-----------------------+-----------------------+-----------------------+ | *Inspiratory Reserve | Extra air you can | 2.4-3000 ml | | Volume* | inhale after a normal | | | | inhalation | | +-----------------------+-----------------------+-----------------------+ Mechanics and Distribution of ventilation ----------------------------------------- +-----------------------------------+-----------------------------------+ | **Control of breathing | - Respiratory canter is located | | (ventilation)** | in the brain stem | | | | | | - Receptors indicate pressures | | | changes and changes in the | | | blood levels which helps | | | control the rate of breathing | +===================================+===================================+ | **Respiration** | - Lungs facilitate gas exchange | | | between the circulatory | | | system and the external | | | environment | | | | | | - Ability of the lungs to | | | stretch  compliance | | | | | | - Lungs are composed of | | | branching airways that | | | terminate in respiratory | | | bronchioles and alveoli, | | | which participate in gas | | | exchange | | | | | | - Gas exchange occurs in the | | | lungs between alveolar air | | | and the blood of the | | | pulmonary capillaries via | | | diffusion | | | | | | - The alveoli are surrounded by | | | capillaries in which O2 from | | | the lungs will diffuse into | | | the blood and CO2 from the | | | blood will enter the lungs to | | | be expelled | | | | | | - For effective gas exchange to | | | occur, alveoli must be | | | ventilated and perfused | | | | | | - **Ventilation (V)** refers | | | the flow of air into the | | | alveoli | | | | | | - **Prefusion (Q)** refers to | | | the flow of blood to the | | | alveolar capillaries | | | | | | - Alveoli will have different | | | degrees of ventilation and | | | perfusion: alveoli at the | | | base of the lung have a | | | greater capacity that the | | | apex of the lung. | +-----------------------------------+-----------------------------------+ | **V/Q ratio** | Changes in ventilation and | | | perfusion in the lungs are | | | measured using the ration of | | | ventilation to perfusion (V/Q) | | | | | | Reduced ventilation: blood but no | | | air  shunt | | | | | | Reduced perfusion: air but no | | | blood  dead space | +-----------------------------------+-----------------------------------+ | **Pleura and the pleural space** | The lungs sit int the plural | | | cavity. The visceral pleura | | | covers the lungs and the parietal | | | pleura covers the internal lining | | | of the thoracic cage | | | | | | Inside the pleural cavity there | | | is pleural fluid which allows the | | | two layers to slide past each | | | other during respiration | | | | | | This fluid helps maintain | | | mechanical coupling between the | | | lungs and the chest | | | wall-preventing the two surfaces | | | from separating during | | | respiration  maintains pressure | | | to keep the lungs inflated | | | | | | There can be acute presentations | | | that impact the pleura and | | | pleural space | | | | | | **Pleuritis**: inflammation of | | | the parietal pleura, mainly due | | | to infection | | | | | | **Pleural effusion:** | | | accumulation of fluid in the | | | pleural space, usually as a | | | result if inflammation of the | | | pleura | | | | | | **Pneumothorax:** accumulation of | | | air in the plural space. Can | | | occur spontaneously or due ti | | | trauma and open chest wounds | | | | | | **Tension pneumothorax:** | | | overaccumulation of air in the | | | pleural space, usually as a | | | result of a valve mechanism. Air | | | enters but doesn't exit during | | | expiration causing an increase in | | | pleural pressure | +-----------------------------------+-----------------------------------+ | **Thorax** | Thoracic cage | | | | | | Protects the heart, lungs and | | | great vessels | | | | | | Ribs: all attach posteriorly to | | | the thoracic vertebrae | | | | | | 1-7  true ribs: attach to the | | | sternum by costal cartilage | | | | | | 8-10  false ribs: attach the | | | sternum by indirectly joining the | | | costal cartilage above it | | | | | | 11-12  floating ribs: have no | | | anterior attachment | | | | | | The dimensions of the thorax need | | | to change for respiration to | | | occur | | | | | | Pump handle: increases AP | | | diameter of the thorax during | | | inspiration | | | | | | Bucket handle movement increases | | | lateral diameter of the thorax | | | during inspiration | +-----------------------------------+-----------------------------------+ | **Respiration Muscles** | Diaphragm | | | | | | Large dome shaped muscle, | | | innervated by the phrenic nerve. | | | | | | During contraction, the diaphragm | | | descends and increases the | | | vertical diameter of the thorax. | | | | | | Intercostals | | | | | | 11 pairs of intercostals which | | | pass between adjacent ribs | | | | | | 3 layers: external (inspiration) | | | , internal (expiration) and | | | innermost (stabilise the chest | | | wall) | | | | | | Accessory muscles | | | | | | Assist with deep respiration or | | | during respiratory distress | | | | | | Scalenes, sternocleidomastoid, | | | pectoralis major and minor | +-----------------------------------+-----------------------------------+ Lung clearance mechanisms (mucociliary clearance, collateral ventilation, cough) -------------------------------------------------------------------------------- +-----------------------------------------------------------------------+ | **Secretion clearance impairment** | +=======================================================================+ | - ↓ secretion impairment Secretion retention: | | | | - Consolidation/collapse V/Q mismatch ↓ O2 and CO2 | | | | - ↑ airway resistance ↑ respiratory load ↓ alveolar ventilation | | ↓ O2 and CO2 | | | | - ↓ cough effectiveness | | | | - To clear secretions, need a strong cough and big breath | | | | - Weak and ineffective cough from: | | | | - Poor technique | | | | - Pain -- post op- not taking a big breath in | | | | - Weakness -- weak inspiratory muscles/abs | | | | - Thick/viscous secretions | | | | - Characteristics of a cough | | | | - Moist or dry? | | | | - Productive or Non-productive (NP) | | | | - Effective or ineffective? | | | | - Paroxysmal? | | | | - Assess sputum quantity and quality (colour, consistency, | | purulence) | | | | - ↓ mucociliary clearance cilia issue, secretion issue | | | | - Cilia they 'beat' to sweep mucous along the beating can be | | affected by smoking, general anesthetic, cold air. Can also ↓ | | no. of cilia (smoking) or damage cilia (burns) | | | | - Aqueous layer lubricates cilia to enhance efficiency impaired | | by ↑ periciliary fluid (pulmonary oedema) or ↓ levels | | (dehydration) | | | | - Viscous layer Ciliary movement can be impaired with | | hypersecretory conditions (CF, bronchiectasis) due to | | increased volume of mucus layer or depletion of sol layer | | | | - ↑ vol of mucous and ↑ thickness of mucous smoking, respiratory | | infections, CF | +-----------------------------------------------------------------------+ Ventilation & Perfusion (V/Q mismatch: shunt and dead space) ------------------------------------------------------------ - V/Q ratio ventilation (flow of air into and out of the alveoli)/perfusion (flow of blood to alveolar capillaries) mismatch = ↓ ability to provide O2 or blood. ↓ ventilation = blood but no air (shunt). ↓ perfusion = air but no blood (dead space)