respiratory failure Flashcards
how many units of energy do you get from a single carbohydrate molecule in presence of oxygen and without oxygen
- with oxygen= 36 ATP molecules
- without oxygen= 2 ATP molecules
how do we inspire (quiet inspiration)
- diaphragm contracts and becomes flat
- external intercostal muscles contract pulling the ribcage upwards and outwards
- contraction of both of the muscles causes the volume of the thoracic cavity to increase which thus decreases pressure (creates this negative pressure- suction effect)
- pressure gradient generated causes air to flow in down pressure gradient
what happens during quiet expiration (passive)
- diaphragm relaxes becomes v shaped
- external intercostal muscles relax- ribcage moves downwards and inwards
- thoracic cavity volume decreases and pressure increases (alveolar and intrapulmonary)
- pressure gradient results in air to flow out as well as the recoiling of the elastin fibres in alveoli
what happens during active expiration e.g during coughing, exercise
- involves muscle contraction
- diaphragm relaxes as well as external intercostal muscles
- internal intercostal muscles contract further pulling the ribcage downwards and inwards
- accessory muscles (abdominal muscles) contract (pushes diaphragm upwards)
- this results in a decrease in thoracic cavity volume increasing the pressure more than in passive expiration
- greater pressure gradient formed air moves out the lungs
what happens during active forced inspiration
- contraction of diaphragm and external intercostal muscles
- abdominal muscles (accessory muscles) also contract
- lung volume increases and thoracic pressure decreases- pressure gradient drives air into the lung
- happens during exercise, respiratory distress such as asthma
why do we get a sore throat when breathing through are mouth
- nasal cavity adds moisture to air
- oral cavity does not
what are the conducting zones
- trachea
- bronchus
- bronchioles specifically terminating bronchioles
- larynx
- pharynx
what are the respiratory zones
- respiratory bronchioles
- alveoli
- alveolar sac
what is the upper respiratory region
- nasal cavity
- oral cavity
- pharynx
- larynx
what is the lower respiratory region
- trachea
- bronchus
- bronchioles (respiratory and terminal)
- alveolar sac
- alveoli
what is tidal volume and what is the anatomical deadspace volume and alveolar volume
- tidal volume 500mls
- anatomical deadspace is 150mls and alveolar volume is 350mls
- anatomical deadspace is fixed and does not change wether you breath fast or slow but alveolar volume can change
what noise do you get with upper airway obstruction and when
- during inspiration
- striddle
what noise do you get in lower respiratory obstruction and when
- during expiration
- wheezing
where is resistance greatest in respiratory system
- resistance is greatest in upper respiratory zone
- flow is turbulent
how is breathing controlled
- dual innervated consists of autonomic control (medulla) and somatic control (hyperventilation)
how does the body increase breathing rate
- chemoreceptors in carotid body and aortic arch sense changes in carbon dioxide, oxygen levels and ph
- this stimulates sympathetic nervous system (medulla)
- causes to breath faster and harder
what happens when sympathetic nervous system fails to work and increase breathing rate
- increased carbon dioxide levels as not cleared
- decrease in ph which can trigger release of nitric oxide
- causes vasodilation
- makes up sleepy
what happens when oxygen cannot get in
- hypoxemic hypoxia
- central and peripheral cyanosis
- organ failure of brain, heart, kidneys
what is cytotoxic hypoxia
- oxygen not utilised by tissues
- cyanide poisoning
- mitochondria do not work
what is respiratory failure and the types
- partial pressure of oxygen <8kPa
- type 1 respiratory failure is when there’s low oxygen but carbon dioxide is also cleared
- type 2 respiratory failure is when there’s both low oxygen and carbon dioxide is not cleared so raised carbon dioxide levels (hypercapnia)
how do we measure oxygen levels
- pulse oximeter to measure hb saturation
- arterial blood gas to measure partial pressure of oxygen
what is the oxygen cascade
- stepwise decrease in partial pressure of oxygen between the atmospheric air and the mitochondria
- essentially shows the decrease In partial pressure of oxygen as it moves from the atmosphere to the specific areas of our body
- drop in oxygen is fixed
- if this drop is altered suggests somethings wrong
- if measuring oxygen in artery need to know much oxygen initially breathing to calculate drop in oxygen
what is the oxygen dissociation curve
- a curve to show hb saturation at different partial pressures of oxygen
- sigmoid shape
- increasing partial pressure increases hb saturation
- positive cooperatively so binding of first oxygen makes it easier for subsequent oxygen to bind
- won’t be able to tell how well lung working of a patient if inspired oxygen very high as there’s mimcl changes in hb saturation when partial pressure Is high
what are some causes of respiratory failure
- pneumonia
- asthma
- pulmonary oedema
- COPD
- pneumothorax
- PE
- opioid poisining
- neuromuscular disease
what is pneumonia, causes, symptoms, what type of lung disease, what can it cause
- caused by pathogen e.g. streptococcal pneumonia, pneumocystis jiroveci
- infection of the lungs specifically alveoli
- shunt (poor ventilation but good perfusion) specifically intrapulmonary shunt where alveoli is obstructed with fluid
- can cause hypoxemic hypoxia
- symptoms include fever, breathlessness, cough
- obstructive lung disease
what is asthma, what type of lung disease, what it causes and treatment, symptoms
- obstructive lung disease
- narrowing of bronchioles (airways) secondary to inflammation
- wheezing and mucus plugging
- shunt
- leads to hypoxemic hypoxia
- leads to exhaustion and therefore ventilation
- use salbutamol a bronchodilator to dilate airways
what is COPD, type of lung disease, causes and mechanism, risk factor
- obstructive
- irreversible with bronchodilator
- caused by high compliance of lungs and low elastic recoil
-associated with emphysema, chronic bronchitis and mucus plugging - smoking is a risk factor
what is pneumothorax
- restrictive lung disease
- hole in lungs and therefore air enters the intrapulmonary cavity but cannot get out and this causes an increase in pressure which causes lungs to collapse, alveolar compressed
- can cause hypoxia
what is pulmonary embolism
- blood clot in pulmonary circulation
- poor perfusion
- dead space- physiological
what opioid poisoning
- reduced ventilatory drive so hypoventilation takes place
- carbon dioxide increases
- drop in oxygen
- shunt
what is neuromuscular disease in terms of respiratory diseases
- smaller breaths
- exhaustion
- rising carbon dioxide
- oxygen falls
what is pulmonary oedema
- swelling of tissues between blood vessels and air spaces due to back pressure from the left ventricle
- more difficult for oxygen diffusion
- build up of fluid
- restrictive
- intrapulmonary shunt
