1002 1-5 Flashcards
in pulmonary system, describe the bronchi
bronchi is conducting airways of lungs
- right main bronchus more vertical
- progressive branching increases
- progressive thinner walls
describe alveoli
Alveoli is the primary gas exchange unit
- pores of Kohn : allow air to pass from alveolus to alveolus
- approx. 300 million in adult
- 2 types of epithelial cells: Type I – structural Type II – secrete surfactant
what is the main driver of breathing
CO2
describe chest wall and pleura
ribs and intercostal muscles
Pleura 3 types
visceral pleura- the membrane covering the lungs
parietal pleura- membrane living the thoracic cavity
pleural cavity- thin or cavity allowing the two surfaces to slide with breathing.
Muscle
major- diaphragm and external intercostal muscles.
accessory- sternocleidomastoid and scalene muscles - increase A/P
explain about respiratory physiology
respiration
central controller - pons, medulla other parts of brain - (output) effectors respiratory muscles - sensors chemoreceptors, lung and other receptors - (input) central controller
how brainstem is involved in control of breathing
complex process controlled from brainstem
- control centre+
afferent + efferent pathways
Respiratory centres in medulla : autonomic control regulated by afferents
- Medullary rhythmicity area
- Pontine respiratory centre
what is afferent
chemoreceptors
what are the 3 types of receptors of LUNG
3 type of receptors:
Irritant: proximal larger airways
Stretch: smooth muscle of airways
J-receptors: near capillaries, pressure sensitive
what are the ions needed in breathing
CO2 - main driver of breathing
CO2 + H2O = H2CO3
H2CO3 = Carbonic Acid
H+ + HCO2 (Carbonate)
describe how efferents are involved in breathing
Efferents:
respiratory centre to diaphragm, intercostal muscles + accessory muscles
phrenic nerve arise from spinal nerves, C3, 4 + 5
intercostal nerves leave spinal cord between T 1+ T 12
inspiration is active + expiration is passive
what is the mechanic of breathing
Mechanics of breathing
- Major and accessory muscles
- Elastic properties of lung and chest
- Resistance to airflow
what is dead space
Dead Space is the parts of the airway that takes no part in gas exchange
what is tidal volume
Tidal Volume is the amount of gas that is inhaled and then exhaled in one breath
how to calculate minute ventilation
Minute Ventilation = (Tidal Volume – Dead Space) X Respiratory Rate
describe Minute Ventilation
The amount of gas that is inspired and exhaled in one minute.
what are the alterations in MV? (the causes of unconsciousness) and why they happen?
Causes of unconsciousness A - Anoxia or alcohol E - Epilepsy I - Insulin (diabetes mellitus) O - Overdose U - Ureamia T - Trauma I - Infection P - Psychiatric/ psychosomatic S - Shock
Trauma to brainstem – brain death Spinal cord injury Nervous system MS, Guillain Barrè Syndrome, Myasthenia gravis Airway – burns, trauma, tumors, foreign objects, inflammation Thoracic chest wall injury # ribs, flail chest Pleural disease or injury Pleural Effusion, pneumothorax, haemothorax Lung disease or injury Asthma Chronic Obstructive Pulmonary Disease Pneumonia Pulmonary Oedema
what is the subjective data of Health history and the examples?
the symptoms that can be seen, observed or gained from patients or their family.
Cough
Onset, how often, time of day, productive (sputum), Haemoptysis.
Shortness of breath – timing, on exertion
Orthopnoea – SOB whilst supine
Paroxysmal nocturnal dyspnoea – awakening at night with SOB
Chest pain with breathing
History of respiratory infections and lung disease
Smoking history
Environmental exposure
what is the scale that can check measure breathlessness?
Borg category-ratio scale – How short of breath are you right now?
0 (nothing at all)- 10( maximal)
what the normal chests look like?
posterior chest
- should be in a straight line
- Symmetrical (even) , in an elliptical shape with ribs in a 45o angle to spine.
anterior chest
Ribs are sloping downwards with symmetrical interspaces
Inspect
Airways – foreign object, swelling, signs of burns, tumors
Note:
facial expressions
Skin colour and condition – cyanosis is a late indication of low oxygen
Respirations
Accessory muscles
Bulging intercostals
Abdominal recession - paradoxical breathing
what is palpation
Using fingers palpate the entire chest wall
-Palpate trachea for position – normally midline
The results are:
Crepitus
Course crackling sensation – subcutaneous emphysema
Caused by air in subcutaneous tissue
Fremitus
Vibration of the chest wall due to vocalization of “99”.
Increased fremitus – lungs become filled with fluid or more dense
Pneumonia, tumors & pleural effusions
Decreased – lung hyperinflated – barrel chest
Absent – Pneumothorax and lung alveolar collapse (Atelectasis)
what are the assessment of respiration?
Respiratory Rate- Number of full inspiration/expirations in one minute (adult: 12-20 infant: 30-50)
Ventilatory Depth - Observing the degree of excursion or movement in the chest wall
Deep respiration, full expansion of the lungs with full exhalation
etc
Ventilatory Rhythm - Breathing pattern – regular or irregular
Men & children – diaphragmatic breathing, seen in lower chest and abdomen
Women – thoracic muscle, seen in upper chest
Ventilatory Sound - Audible by ear,
Stertor – snoring sound when secretions block the trachea or large bronchi
Stridor – inspiratory wheeze indicating upper airway obstruction
Wheezing – high pitch musical sound occurring on inspiration, indicating partial obstruction of small (lower) airways
Inspiratory grunt – babies – occluded airway
what can you check though auscultation?
breath sounds
normal:
Bronchial: loud, high pitched
Bronchovesicular: medium pitched
Vesicular: soft, low pitched, gentle, rustling sounds
abnormal:
Nil
Wet – Crackles or Rales = pulmonary oedema
Noisy - Rhonchi: air passing past sputum = pneumonia
Wheeze: narrow airways = asthma
how to do percussion?
Starting over the apices, percuss the interspaces at 5cm intervals moving from side to side for comparison.
Avoid dampening effect of bone (scapula and ribs)
Resonance – normal low-pitched, clear hollow sound over lungs
Hyperresonance – lower-pitched, booming sound – too much air as in Pneumothorax and Emphysema
Dull – abnormal density in lung as with pneumonia, pleural effusion, atelectasis or tumour
Percussion has a 5-7cm depth limit
what is the pulmonary function test?
Peak expiratory flow meters :
Is the point of highest flow during maximal expiration
Serial monitoring
Intra-individual accuracy
Limited assessment of respiratory diseases
Peak expiratory flow (trend of lung function)
spirometry:
Gold standard
Diagnostic
High reliability
what are the things to be checked in lung function tests?
Four volumes: tidal volume (VT): volume of inspired or expired air per breath
inspiratory reserve volume (IRV): volume that can be inspired above TV
expiratory reserve volume (ERV): volume that can be expelled at end of TV
residual volume (RV): volume of gas remaining in the lungs after maximal expiration
Four capacities: inspiratory capacity (IC) functional residual capacity (FRC) vital capacity (VC) total lung capacity (TLC):volume of gas in lungs after maximal inspiration
what is use of pulse oximetry
pulse oximetry is for Relative measure of percentage of bound oxygen to haemoglobin
- COPD patients n=64
- Acute exacerbation
- Comparison of oximeters
- Significant hypoxia PaO2 < 60 mmHg
describe Capnography
it is to confirm endotracheal tube placement during emergency airway management - > 2000 intubations.
what are the 4 major components of respiratoration
Mechanical movement of gases into and out of lungs – (mechanism of breathing) – last week’s lecture
Gas exchange across alveolar membrane
Carriage of gasses to and from tissues
Metabolic processes of the cell to produce energy
explain use of oxygen in cells?
Production of Adenosine Triphosphate (ATP) for energy requires delivery adequate level of Oxygen (O2) to cells
Electron transport system in mitochondria supplies 95% of cellular energy but uses 90% of DO2
This delivery of oxygen (DO2) is dependent on cardio-vascular sufficiency, the focus of future lectures
Without oxygen, cells die.
why DO2 important ? (dissolved oxygen)
Inadequate DO2 will cause:
Pyruvic acid converts to lactic acid
Drop in intracellular pH
Diminished protein synthesis, denaturing of existing proteins
Free fatty acid accumulation, swelling of intracellular organelles
Sodium-potassium pump dysfunction
Tissue/organ failure
Without oxygen, cells die.
what is the alteration of PaO2
Decreased partial pressure of inspired oxygen Altitude Suffocation Increase in other gasses in air eg carbon monoxide Ventilation/perfusion (V/Q) mismatch Decreased Ventilation - Shunting Airway occlusion eg COPD Fluid in lungs eg pulmonary oedema Alveolar collapse Decreased Perfusion – Dead Space Decreased cardiac function Decreased BP Pulmonary emboli
oxygen transport, why oxygen is carried in blood?
O2 considerably less soluble than CO2 Due to ability to form carbonic acid where as O2 has no ability Carbonic Acid (H2CO3) = H2O + CO2 Therefore most O2 carried attached to haemoglobin (about 97% of total) Measured as SpO2 (peripheral monitor) or SaO2 (arterial gas analysis) The remainder 3% is dissolved in plasma Measures as PaO2
oxygen saturation?
% of oxyhaemoglobin in total (saturated and unsaturated) haemoglobin
Normal SaO2 = 98%
Normal SvO2 = 75%
Difference is a reasonable estimate of oxygen extraction by cells
what is the oxygen consumption and oxygen extraction ration
Volume of oxygen consumed by the tissues per minute (VO2)
Reflects body cellular metabolism
Norm 3.5 ml/min/kg resting
At rest 250 ml/min
Exercise 3600 ml/min
\
Estimate of the balance between oxygen usage by cells and oxygen delivery
-VO2: DO2
- OER = 22-32%
describe arterial blood gases
Using an arterial blood sample we can measure: pH – acidity or alkalinity normally 7.35 – 7.45 <7.35 acid >7.45 alkaline PaO2 – partial pressure of oxygen in arterial blood Normally 80-100 mmHg PaCO2 – partial pressure of oxygen in arterial blood Normally 35-45 mmHg > 45 acid < 35 alkaline Bicarbinate - normal 21-26mmol Base Excess - -2 to +2 mmol/L
describe the blood gas analysis
Simple steps
1. Determine whether the blood is acidic or alkaline by examining pH
2. Determine the primary cause of the pH
- Examine PaCO2 to determine respiratory cause of acidosis or alkalosis
- Examine Bicarbonate and 3. Base Excess to determine renal cause of acidosis or alkalosis
4. Determine if there is respiratory/renal compensation
Determine oxygen status by examining PaO2 and SaO2
describe pulse oximetry (finger thing)
Relative measure of percentage of bound oxygen to haemoglobin
SaO2 = HbO2 / Total Hb
Two wavelengths – visible and infrared beams
Measure absorption in pulsatile element of blood flow between Hb and Hb02
Use of pulse oximetry COPD patients n=64 Acute exacerbation Comparison of oximeters Significant hypoxia PaO2 < 60 mmHg
simply explain respiratory physiology
Three steps in the process of oxygenation:
- Ventilation (gas in and out of lungs)
- Diffusion (o2 and Co2 in the alveoli and capillaries of body tissue)
- Perfusion of lungs (move blood to and from the alveolocapillary membrane for gas exchange to occur)
- The respiratory centre lies in the brainstem and controls respiration
- Chemoreceptors respond to change in the chemical composition
• Central – detects changes in pH (adjust inspiration rate and depth)
• Peripheral – detect arterial O2 and CO2 Predominantly o2 therefore adjust
respiration in response to hypoxaemia (Craft, et al 2015)
what are the factors effecting oxygenation
- Physiological
- Developmental
- Behavioural
- Environmental
the alternations in respiratory functioning
and they contribute-
Alveolar hyperventilation
• Ventilation in excess of that required to eliminate carbon dioxide
produced by cellular metabolism • Alveolar hypoventilation
• Ventilation inadequate to meet the body’s oxygen demand or to eliminate sufficient carbon dioxide
• Atelectasis
• Collapse of the alveoli, preventing normal diffusion of oxygen
and carbon dioxide
and they contribute
- Ventilation/perfusion mismatch
• Diffusion impairment
• Alteration in membrane thickness and/or surface area which results in impaired gas exchange
• Hypoxia
• Inadequate tissue oxygenation at the cellular level
• Cyanosis
• Blue discoloration of the skin and mucous membranes, caused by the presence of desaturated haemoglobin in capillaries, is a late sign of hypoxia
what are the signs and symptoms?
CNS Unexplained apprehension Unexplained restlessness or irritability Unexplained confusion or lethargy Combativeness Coma Respiratory Tachypnoea Dyspnoea on exertion Dyspnoea at rest Use of accessary muscles Retraction of interspaces on inspiration Pause for breath between sentences, words Cardiovascular Tachycardia Mild hypertension Dysrhythmia’s (pre mature ventricular contraction) Hypotension Cyanosis Cool clammy skin Other Diaphoresis Decreased urinary output Unexplained fatigue
respiratory assessment diagnostic test for different 4 parts?
Ventilation and oxygenation studies
- Pulmonary function test spirometry
- Peak expiratory flow
- Arterial blood gas
- Oximetry
Viewing structures of the respiratory system
- Chest X-ray examination
- Bronchoscopy
- Lung scan (CT)
what are the common asthmatic symptoms or signs? triggers? and risk?
- Bronchoconstriction
- Oedema of airways
- Mucous hypersecretion
triggers: allergens drugs aspirin cold air stress
risks:
family history
history of allergies
age
