Breathing Flashcards
What is the oxygen delivery equation?
Do2= co [ (hb x 1,34) sao2 +0,003 pao2 ]
Sa02 = % of haem binding sites saturated with 02
Pa 02= amount o2 dissolved in plasma
Which 3 factors is oxygen flux dependent on?
• co
• hb
• pao2
Name 6 causes of oxygen dissociation curve shift to left
(Increased hb affinity for 02, especially in lungs)
• increased ph, decreased H
• decreased pco2
• decreased temp
• decreased 2,3- dpg
• fetal haemoglobin
• carboxyhaemoglobin
Name 4 causes of oxygen dissociation curve shift to right
( Decreased hb affinity for 02- release)
• decreased ph, increased H
• increased pco2
• increased temperature
• increased 2,3- dpg
Indications for oxygen therapy (6)
Hypoxaemia /hypoxia
• systemic hypoxia: pao2 <60 or sao2 <90 on room air
• regional hypoxia eg acute coronary syndrome , threatened limb etc
Shock
Respiratory distress
Carbon monoxide poisoning
Anaemia
Etc
Name 4 types hypoxia
- Cardiogenic/ischaemic / stagnant: drop in co
- Anaemic: drop hb
- Hypoxic: drop pao2 and sao2
- Hystotoxic: eg cyanide poisoning. Inhibit cellular resp
All indications for oxygen!
Name 5 risks prescribing supplemental oxygen
- Fire
- Retrolental fibroplasia in neonates (retinopathy of prematurity)
3.02 induced hypoventilation eg copd, CO2 narcosis: lowers respiratory drive → respiratory depression → increase paco2 - Oxygen toxicity if > 16-24 hours on 100% : oxygen free radicals, pulmonary oxygen toxicity
- Absorption atelectasis :room nitrogen is 78% - wash out of nitrogen from alveoli with oxygen lead to atelectasis ( nitrogen one of things that keep alveoli open)
What does an oxygen flow meter regulate?
Fi02: fractional inspired concentration of oxygen.
Calibrated from 1-15 lpm
Name 3 examples of low flow oxygen delivery device and function.
Deliver oxygen at less than patient’s peak inspiratory flow rate so that the oxygen is diluted by room air.
• nasal cannulae
• simple face mask
• non - rebreathing and partial rebreathing face masks
Name example of high oxygen delivery device and function.
Deliver oxygen at rate in excess of patient’s pifr to allow for more precise titration
Eg venturi face mask
Indication reservoir bag masks?
Emergency oxygenation for patient able to breathe on own. temporary.
Function of hudson mask?
Nebulising
Name 5 causes falsely high pulse oximetry
• Anaemia
• sats <70
• carboxyhemoglobin
• methemoglobin
• circulating dye eg methylene blue
Name 5 causes falsely low pulse oximetry
• Poor perfusion: vasoconstriction/ low co
• dark skin
• nail polish
• fungal nail infection
• methemoglobin
What does capnogram measure?
End tidal co2 (etco2)
Normal etc02? ( mmhg and % )
5-6%
35 -45 mmhg
Name 6 causes increase in etco2
• Malignant hyperthermia
• increased cardiac activity
• Bicarbonate infusion
• increased muscular activity (shivering)
• effective drug therapy for bronchospasm
• tourniquet release
Name 6 causes decrease in etco2
• Decreased muscular activity : relaxants
• hypothermia
• decreased cardiac output (cardiac arrest)
. Pulmonary embolism
• increased minute ventilation,
• bronchospasm
Name 6 indications intercostal drain
• Pneumothorax
• haemothorax
• empyema
. Prophylaxis chest injury before positive pressure ventilation or aeromedical transfer
• pleurodesis (to obliterate pleural space to prevent recurrent effusion or pneumo)
• pleural lavage for rewarming
Name 3 contraindications intercostal drain
•Lung adherent to chest wall
• loculated chest collections
• uncorrected coagulapathy.
Name the borders of the rectangle of safety for intercostal drain
Superior : base of axilla
Inferior: line of fifth intercostal space
Anterior: lateral edge pec major
Posterior : edge latissimus dorsi
Site of insertion of icd?
4th or 5th intercostal space (superior border rib) between anterior and mid axillary lines within rectangle of safety
Sizes icd in adults?
24-28
Sizes icd in children?
16-20
Name 3 immediate complications intercostal drain
• Haemorrhage from trauma to intercostal vessels or lungs
• penetrating trauma to lungs, diaphragm, liver, spleen
• malpositioning: intra abdominal
Name early complications intercostal drain
Re-expansion pulmonary oedema
Name 2 late complications intercostal drain
• Empyema
• retained haemothorax
Name 3 indications for removal intercostal drain
• No continuing air leak : drain no longer swinging or bubbling
• fluid being drained <50 ml last 24h
• recent cxr show re-expanded lung and resolved haemothorax.
Name the clinical signs pneumothorax. (3)
Chest wall movement decreased over affected side
Resonant to percussion
Breath sounds absent or greatly reduced
Name xr signs of tension pneumo (2)
Mediastinal shift away from pneumo
Depressed hemidiaphragm on side of pneumo