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
Name clinical signs haemothorax (5)
Heart displaced to opposite side. Trachea only displaced if massive
Chest wall movement reduced over affected area
Stony dull to percussion
Breath sounds absent over fluid, may be bronchial at upper border.
Pleural rub may be found above effusion
Signs pneumomediastinum on xr? (2)
• Mediastinal pleura displaced from heart border
• continuous diaphragm sign (can see central pant)
Which side of the diaphragm usually ruptures?
Left (right protected by liver )
Fastest way to decompress tension pheumothorax?
Finger thoracostomy
Initial Treatment open pneumothorax?
• Oxygen
• 3 sided dressing on lesion to prevent tension - prevent air from entering during inspiration but allow to leave on expiration
Define massive hemothorax(3)
• Drain more than 1500 ml and symptoms and signs shock
• ongoing 250 ml /h in 6 hours, or >300 ml /h in 4 hours (monzon: ≥ 200 ml /h in 4-6h)
• shock and white - out lung (clot) on xr
See picture 26 and label the spirogram
See picture 27
Name equipment needed for intubation (10)
• 5 metals
1.lanyngoscope
2. Extra blades
3. Magill’s forceps
4. Introducing stilette
5.artery forceps
• 5 plastics
1. Syringe
2.ett
3. Mask
4-opa (guedel)
5. Airway filter
Suction tip
What is the initial management of tension pneumothorax? (3)
• Supplemental oxygen
. Emergency needle decompression 5th intercostal space anterior to midaxillary line
• Emergency finger thoracostomy may be used as precursor of ICD insertion
Do not intubate- positive pressure ventilation will worsen! Unless absolutely necessary!
What is the definitive management of tension pneumothorax?
• Intercostal drain insertion
• only then assess chest xray resolution
• manage associated injuries eg haemothorax, tracheo-bronchial injury
What will cause open pneumothorax?
Wound or defect in chest wall 2 times larger than trachea diameter (>3cm)
Name 5 clinical manifestations open pneumothorax
• Sucking chest wound- bubbling
• tachypnea, dyspnoea, resp distress
• severe hypoxia
. Low GCS
. Signs shock if associated bleeding (may be associated with thoracic haemorrhage)
Definitive Treatment open pneumothorax? (3)
• ICD _ never through same wound!
. Surgical debridement and closure of wound in layers- must be airtight
• treat haemothorax if present
• X-ray after
Name 6 Common sources of haemothorax from most to least common
- Intercostal arteries and veins
- Internal mammary (thoracic) artery
- Lung parenchyma
- Mediastinal great vessels- aorta, cava, pulmonary artery
- Heart (50% die on field so uncommon in ED)
- Abdominal organs via diaphragm laceration
Management of massive haemothorax? (5)
• Secure airway - intubate
• administer oxygen
• initiate emergency blood transfusions, can autotransfuse
• Emergency thoracotomy = definitive
• complete shock resuscitation
Never clamp ICD if massive! Doesn’t control bleed, just hides it
Which antibiotics should be given prior to ICD insertion and why?
Cephalosporin or co-amoxiclavulanic acid (for S aureus and epiderm - clean contam wound)
To prevent empyema
Which antibiotics should be given for penetrating abdominal trauma and why?
Co-amoxiclavulanic acid for aerobic and anaerobic cover.
Single dose unless exposure to gut content, then 3-5.
If haemorrhagic shock, double dose or shorter interval of second dose
Which antibiotics should be given for maxillofacial trauma and why?
Co-amoxiclavulanic acid for aerobic and anaerobic cover.
Often communicate with oral cavities, sinus cavities or skin therefore open fracture.
Which antibiotics should be given for soft tissue wounds and why?
1st or 2nd generation cephalosporins: cefazolin.
Only if wound is grossly contaminated and can’t be adequately cleaned. No need in simple wounds
Name 4 goals of lung protective ventilation
• Minimize fi 02
• plateau pressure ≤ 30 cm H2O
• tidal volume 6-8 ml /kg (pbw)
• peep
Name the 2 types of respiratory failure
Type 1 hypoxia
Type 2 hypercapnic
Name 8 causes respiratory failure in trauma
• Effusion
• ARDS
• contusion
• pneumothorax
• Atelectasis
• pneumonia
• aspiration
• pulmonary emboli’s
Name 2 causes ARDS broadly
Primary or direct: injury to alveoli
Secondary or indirect: vascular endothelial injury
Name 10 risk factors ARDS
• Massive sirs response (shock)
• sepsis
• Trauma
• drowning
Pancreatitis (sirs)
• high net positive fluid balance
. Blood and plasma transfusion !
• fat embolus !
Aspiration pneumonia!
• Burns
• Heart bypass
•Dic
Name the 3 pathological change phases and time of onset of ARDS
- Inflammation/exudation: 1-2 days
- Proliferation 1-2 days
- Fibrosis 2-4 weeks
How treat phase 1 (inflammation/ exadation) of ARDS? (5)
• Mostly supportive
• treat cause
• peep
• inverse ventilation - inspiration: expiration 2:1
• ventilate prone
How treat phase 2 (proliferation) of ARDS?
• Inhaled No may help via vasodilation at ventilated areas of lung to improve v/Q mismatch
How treat phase 3 (fibrosis) of ARDS?
Steroids
Define the Berlin criteria of ARDS according to timing, chest imaging, origin of oedema and oxygenation
• Within 1 week of known clinical insult or new or worsening respiratory symptoms
. Chest imaging bilateral opacities not fully explained by effusions, lobar/lung collapse or nodules
• respiratory failure not fully explained by cardiac fail or fluid overload. Need objective assessment eg echo to exclude hydrostatic Edema of no risk factor present
• oxygenation
Mild :. 200 mm Hg < pao2 / fio2 ≤ 300 mm Hg with peep or CPAP ≥ 5 cm H2O
Moderate: 100 < pao2 /fio2 ≤ 200 with peep ≥5
Severe: pao2 / fio2 ≤100,
Refractory hypoxemia !
Name 4 contraindications to proning
• Haemodynamic instability (can induce cardiac arrest)
. Spinal fractures
• open chest
• pelvic fractures that are unstable or exfixed
Name 6 indications ventilation
• Hypoxia
• hypercapnia
• reduce work of breathing
• airway control
• correct acid base status
• shock
How approach a patient desaturating on the ventilator?
Dopes
Displacement et tube
Obstruction et tube
Pneumothorax, pe, pulmonary oedema, bronchospasm
Equipment -ventilator disconnections or problems
Stacked breaths- bronchospasm and inappropriate ventilator settings
Name 6 complications ventilation
• Barotrauma
• air trapping - auto peep
• hemodynamic instability
• ventilator associated pneumonia
• oxygen toxicity
• cardiovascular effects
• diaphragmatic dysfunction
What are the best settings for mechanical ventilation - tidal volume, rr, fi02, flow rate, peep
• Tidal volume 6 ml /kg PBW
• rr 10-15
• fi02 21 to 100%, preferably <50%
• flow rate 4x minute ventilation, 40-60 L min
. Peep 8 cm h20
When is ORIF indicated in flail chest? (4)
-anterolat flail chest
-3 or more non-flail fractures but with displacement
- severe pain
-chest wall deformity
When is ORIF contraindicated in flail chest?
Severe TBI or other indication for ventilation
Cause o haemoptysis in a post-op trauma patient? (Most likely )
Pulmonary embolism
Normal p/f ratio?
> 400
Acute lung injury p/f ratio?
<300
ARDS p/f ratio?
<200
Pa 02 in acute respiratory failure in mmhg?
<60
Pac02 in acute resp failure in mm Hg?
> 50
Physiologic peep?
5
% Mortality of ARDS?
35-45
How correct respiratory acidosis on ventilator?
Increase minute volume
