Makindo Medical Notes.com

Hypoxia kills. Oxygen points can usually deliver up to 15 L/min of oxygen. Oxygen delivery depends on many variables including mask type, patient respiratory rate and minute volume. Just increasing flow does not always mean high FiO₂. The concentration of oxygen the patient breathes in is determined by the type of mask as well as the flow from the wall and the breathing pattern. By using a fixed performance system (Venturi)you can gauge the percentage much more accurately

Indications for use

• Correcting hypoxaemia, Pneumothorax (helps resorb air)
• Acute myocardial infarction, Severe trauma
• Post anaesthesia recovery
• Acute severe asthma, Acute pulmonary oedema
• Acute respiratory distress syndrome
• Acute sicking crisis if hypoxic
• Cluster headaches, Carbon monoxide poisoning

Precautions and or possible complications: (Support saturations with least FiO₂)

• May depress ventilation in some patients with chronic hypercapnia (CO₂ retainers)
• May cause atelectasis (60% 0₂) in partially obstructed patient with use
• Oxygen toxicity (> 50% 0₂ < 24-48 hours
• In premature infants, can cause Retinopathy of Prematurity (ROP)

Types of Oxygen Delivery Devices

• Nasal Cannula:
  • Delivers low-flow oxygen (1-6 litres per minute).
  • Provides 24-44% oxygen concentration.
  • Used for patients with mild respiratory distress or chronic oxygen needs.
• Simple Face Mask:
  • Delivers moderate-flow oxygen (6-10 litres per minute).
  • Provides 40-60% oxygen concentration.
  • Used for patients requiring higher oxygen concentrations than a nasal cannula can provide.
• Venturi Mask:
  • Delivers precise oxygen concentrations (24-60%) at specific flow rates.
  • Used for patients with chronic obstructive pulmonary disease (COPD) to prevent hypoventilation.
• Non-Rebreather Mask:
  • Delivers high-flow oxygen (10-15 litres per minute).
  • Provides 60-100% oxygen concentration.
  • Used for patients with severe respiratory distress or hypoxia.
• High-Flow Nasal Cannula (HFNC):
  • Delivers high-flow oxygen (up to 60 litres per minute).
  • Provides up to 100% oxygen concentration with heated and humidified air.
  • Used for patients with moderate to severe respiratory distress.
• Bag-Valve Mask (BVM):
  • Manual resuscitator used to deliver positive pressure ventilation.
  • Provides nearly 100% oxygen concentration when connected to an oxygen source.
  • Used in emergency situations for patients who are not breathing adequately.
• Continuous Positive Airway Pressure (CPAP):
  • Delivers continuous positive pressure to keep airways open.
  • Used for patients with obstructive sleep apnoea or severe respiratory distress.
  • Provides variable oxygen concentration depending on the setup.
• Bilevel Positive Airway Pressure (BiPAP):
  • Delivers two levels of pressure: higher during inhalation and lower during exhalation.
  • Used for patients with COPD, obstructive sleep apnoea, or respiratory failure.
  • Provides variable oxygen concentration depending on the setup.

Clinical Indications

• Hypoxemia:
  • Low levels of oxygen in the blood requiring supplemental oxygen to maintain adequate oxygen saturation levels.
• Respiratory Distress:
  • Conditions such as asthma, pneumonia, COPD exacerbations, and acute respiratory distress syndrome (ARDS).
• Postoperative Care:
  • Patients recovering from surgery may require supplemental oxygen to ensure adequate oxygenation during the healing process.
• Chronic Conditions:
  • Patients with chronic lung diseases such as COPD, interstitial lung disease, or pulmonary fibrosis may need long-term oxygen therapy.

Adjusting Oxygen therapy

Mode	About	Use	Image
Room Air	Atmospheric air contains 21% oxygen. Even a modest increase can improve tissue oxygenation	Those without additional oxygen requirement and SaO2 > 94% or those with hypercapnia and COPD
Nasal Cannula [Delivers FiO2 24-44%]	A nasal cannula (NC) comprises a thin tube with two small nozzles that protrude into the patient's nostrils. It can only comfortably provide oxygen at low flow rates. Low flow delivery system. Flow rate: 1 - 6 L/min. FiO₂ starts at 24% for 1L/min and increases 4% for each L/min up to 44% for 6 L/min. Usually Well tolerated - some find this preferable to a face mask. No dead space. Must be low flow as rate: > 6 L/min cause nasal mucosal drying and nose bleeds. Use: minimal or no respiratory distress or oxygenation problem	Mild hypoxia and stable. O₂ sats stable and above 90% and otherwise normal observations
Simple (Hudson) Face Mask [Delivers FiO₂ 24-44%]	Low flow delivery system. Small space. Use at 5-8 l/min. Must flow at over 5L/min to flush away expired CO2. Flow rate determines FiO2: 5 - 6 is 40%, 6 - 7 is 50%, 7 - 8 is 60%. Mask doesn't need tight seal. Use as one would with nasal prongs but requires higher concentrations	Same as nasal cannulae. May be preferred for comfort
Venturi Mask	High flow delivery system with flow rate b/w 4 - 12 L/min. FiO2 can be set specifically with different flow rate and air ports. Fi02 can be 24, 28, 31, 35, and 40%. External ports must remain open to entrain room air. Use in COPD patients that require specific oxygen concentrations to administer high Fi02 but not too high such that the hypoxic drive to breath is blunted; titrate to keep sats about 88-92%	Used to give precise FiO₂ so may be useful with COPD and CO2 retention and need to give 24 or 28% oxygen. Colour codes BLUE = 2-4L/min = 24% O2 WHITE = 4-6L/min = 28% O2 YELLOW = 8-10L/min = 35% O2 RED = 10-12L/min = 40% O₂ GREEN = 12-15L/min = 60% O₂
Non-Rebreather with Reservoir Bag	High flow delivery system giving high FiO₂. This mask utilizes 3 one-way valves and an oxygen bag reservoir. Supplies the highest possible oxygen concentration of any of the masks. Flow rate 6 - 15 L/min supplies 50-70% Fi02. Requires tight-fitting mask Flow can set to meet the patient's maximum inspiratory needs. The bag should not completely deflate on inspiration. Should be used when over 50% oxygen required. Use it in any spontaneously breathing patient who requires the highest FiO₂. Indications - carbon monoxide poisoning, trauma, severe asthma, pulmonary oedema, acute PE etc	Sick patients severe Asthma, LVF, Shock, Anaphylaxis, Acute PE, Acute pneumonia
CPAP/NIV	Positive pressure throughout respiratory cycle Prevents collapse of airways recruiting more alveoli for gas exchange and reduces the work of breathing. Can be accompanied by high FIO₂. Starting pressure is 5 cm H₂O. See topic	Type 1/2 Respiratory failure. NIV used for COPD. CPAP for Pulmonary oedema