Basics of breathlessness Flashcards
What is breathlessness?
Breathlessness is a subjective, distressing sensation of awareness of difficulty with breathing
How does oxygen get into cells?
- Alveolus - Oxygen has to get from the outside to the alveolar capillaries
- Alveolar capillary - Oxygen needs to be taken up by Hb in the RBCs
- Blood vessel -RBCs need to be transported to the areas of oxygen demand
- Tissue capillary -Oxygen is used by the cells in respiration
Environment → Cells
What is the main drive for breathlessness?
HYPOXIA
What are the different types of hypoxia?
1.Hypoxic Hypoxia
Not enough oxygen getting into the blood from the environment (e.g. High Altitude, Hypoventilation (e.g. due to opioid overdose), Ventilation/Perfusion Mismatch)
2. Anaemic Hypoxia
Insufficient Hb to collect oxygen to carry in the blood.
3. Stagnant Hypoxia
Oxygen in blood is ineffectively circulated to areas of demand.
4. Histotoxic Hypoxia (VERY rare - problems with cells)
Sufficient oxygenation to tissues, however cells cannot use it.
What is this an example of?
Central Cyanosis: (around the core, lips, and tongue) - is a BAD sign as is central → NOT peripheral
Central Cyanosis = Major causes of hypoxia/hypo-perfusion
What is cyanosis?
Is the blue discolouration of the skin or mucous membranes due to the tissue near the skin surface having low oxygen saturation
What is this an example of?
Peripheral Cyanosis: (only the extremities or fingers).
What are the causes central cyanosis?
- Respiratory diseases (COPD, Pneumonia, PE)
- Cardiovascular (Heart Failure, Congenital Heart Disease - most common cause)
- CNS (Respiratory Depression) (ICH, Drug Overdose)
What causes peripheral cyanosis?
- Reduced Cardiac Output (i.e. Poor Stroke Volume/Shock)
- Hypothermia (Peripheral blood vessel shut down)
- Arterial/Venous Obstruction
What some causes of breathlessness? (fill in table)
- Bronchiectasis - is chronic inflammation of the bronchioles causing clogging the airways, decreasing the SA and this DECREASING gas exchange
- Pleural effusion, pneumonia, lung cancer - are in the lungs when shouldn’t be there
- Acidosis - hyperventilate to get rid of CO2
- Pregnancy - push up on diaphragm
- Arrhythmias - affects how heart pumps
What is the definition of hyperventilation?
Hyperventilation occurs when the rate or tidal volume of breathing eliminates more carbon dioxide than the body can produce
What are the causes of hyperventilation?
- Physiological Stress (i.e. increased CO2 production by active cells - e.g. in sepsis).
- Anxiety/Panic.
- Head Injury/Brain Injury (more commonly causes hyp_o_ventilation)
- Respiratory Disease (e.g. Asthma/Pneumonia/COPD – difficult to eliminate CO2 from the body at normal respiratory rate).
- Cardiovascular Disease (e.g. Heart Failure, Anaemia).
- Acidosis (e.g. DKA, Lactic Acidosis)
ABG very good way of determining if patient is hyperventilating appropriately
What are some signs/symptoms of hyperventilation?
- Dizziness e.g. alkalosis caused by DECREASE in CO2
- Breathlessness
- Heart palpitations
- Numbness & tingling (peripheral paraesthesia - burning* or prickling *sensation that is usually felt in the hands, arms, legs, or feet, but can also occur in other parts of the body)
How do we treat all of these breathless/cyanosed/hyperventilating patients?
- NASAL CANNULA: Connected to oxygen at the wall. Sit in the patients nostrils and curl around their ears to stay in place.
- VENTURI MASK: Coloured clip at the bottom of the mask controls how much additional air is entrained into the mask. It tells you how many litres of oxygen to deliver from the wall in order to deliver the correct percentage of oxygen with that clip. Can connect other devices such as nebuliser.
- SIMPLE MASK: Connect to any flow of oxygen from the wall. Uncertain amount of additional air breathed in by the patient. Can connect other devices such as nebuliser.
- NON-REBREATHE MASK: Has an oxygen reservoir bag at the bottom of the bag to maximise how much oxygen does into the patient.
CASE VIGNETTE:
67 year old lady with urosepsis. She has a reduced conscious level but is maintaining her airway. Her oxygen saturations are 76%. Her PMH includes hypertension only.
Which device is suitable for her oxygen delivery?
ANSWER: 15L non-rebreathe mask.
CASE VIGNETTE:
88 year old gentleman who is recovering from a pneumonia on a COTE ward. He is sat up in bed, but when he has conversations with the nursing staff he feels a little breathless. He needs approximately 3L of oxygen to maintain his saturations between 94-98%. He has a past medical history of prostate cancer and hypothyroidism.
Which device is suitable for her oxygen delivery?
ANSWER: 3L NC oxygen.
CASE VIGNETTE:
54 year old gentleman with COPD. ABG results from his admission show a chronically raised bicarbonate. He is recovering from surgery for a fractured neck of femur and needs oxygen post-operatively.
What is the appropriate method of oxygen delivery?
ANSWER: Venturi Mask + titrate aiming for saturations of 88-92%.
CASE VIGNETTE:
74 year old lady with COPD. She is admitted with an infective exacerbation of COPD, and has oxygen saturations of 68% on room air. She looks significantly breathless and is sat in the tripod position.
What is the appropriate method of oxygen delivery?
ANSWER: 15L Non-rebreathe mask.
