Hypoxemia

the way pt breathing?
vitals (SaO2,BP,RR)

Hypoxemia= Low O2 in blood
Hypoxia= Low O2 at tissue level
Hypoxia causes: (Hypoxemia, Anemic, ischemia, toxic)

Hypoxemia causes:

  1. apnea/hypopnea (Opioid,OSA,OHS,Benzo,anesthesia,stroke,Neuromuscula,OHS,muscle exhaustion in COPDexac,cardiac arrest)

  2. diffusion defect: (ILD,IPF, usually chronic, HomeO2)

  3. Shunt (V/Q): V problem, Crap in alveoli (pus (PNA), blood (PH), Fluid (ARDS, edema) collapsed (Atelectasis), high a-a, bad lungs

  4. Dead-space (V/Q): Q problem, perfusion to alveoli problem, (PE)

  5. High altitude

Hypoxia + hypotension

  1. PE + tachy

  2. Tension Pneumothorax + absent breath sounds

  3. Sepsis

Approach:
-- NC(6L,45%)-NRM (15L,60-70%)-> not fixing-> shunt (Crap)-> need PP (HF,BIPAP,CPAP)-> CXR,CBC,AC?,edema?,Fever?
-- NC(6L,45%)-NRM (15L,60-70%)-> fixing-> dead space-> PE?

DX

  • ABG (PaO2,BiPAP vs intubation) repeat 1-2 hr

  • CC panel (lactate)

  • CBC (Hgb,WBC)

  • BMP (HCO3,Lytes,Cr)

  • trop (CP,MI)

  • CXR (PNA,HF,Atelectasis,PTX)

  • EKG

  • echo (HF?)

  • CT (PE?)

1. Nasal Cannula (NC)

  • Flow: 1–6 L/min

  • FiO₂: ~25–45% (+3–4% per 1 L)

  • Type: Variable

  • Notes:

    • Humidify if >4 L

    • Mixes with room air (21%)

    Use: Mild hypoxia, stable pts

2. Simple Face Mask

  • Flow: 6–10 L/min (minimum 6)

  • FiO₂: 35–50%

  • Type: Variable
    Use: Moderate O₂ need
    Must keep ≥6 L → avoid CO₂ rebreathing

3.Venturi Mask (NO bag)

  • Flow: ~4–12 L/min (depends on adapter)

  • FiO₂: ~24–50% (PRECISE)

  • Type: Fixed FiO₂

  • Notes: Can humidify
    Use: COPD / need precise FiO₂

4. Non-Rebreather (NRB)

  • Flow: 10–15 L/min

  • FiO₂: 80–95%

  • Type: High FiO₂

  • Notes:

    • Bag must be 2/3 inflated

    • Has reservoir
      Use: Severe hypoxia / bridge to escalation

5. HFNC (Heated/Humidified High Flow)

  • Flow: 10–60 L/min

  • FiO₂: 21–100% (titratable)

  • Type: High-flow, heated/humidified

  • Effects:

    • ↓ RR, ↓ WOB

    • Mild PEEP effect >30L
      Use: Moderate–severe hypoxia, PNA
      Better than NIPPV if aspiration risk
      Use max flow + FiO₂ in acute decompensation

⚡ NIPPV (Non-Invasive Ventilation)

CPAP (Continuous)

  • Effect: Oxygenation only

  • Pressure: ~10 cm H₂O

  • Use:

    • CHF / pulmonary edema/ atelectasis

    • Hypoxia without hypercapnia, not too Tachypnea

  • Mechanism:

    • Keeps alveoli open

    • Pushes fluid out

BiPAP (IPAP/EPAP)

  • Effect: Oxygenation + ventilation

  • Settings:

    • EPAP ~5-10 -in O2

    • IPAP ~10-15 (5 above EPAP)- off co2

  • Use:

    • COPD, OHS, hypercapnia

    • Tachypnea, low TV (big to blow off Co2)

  • Mechanism:

    • ↓ WOB

    • ↑ tidal volume

    • Blows off CO₂

CONTRAINDICATIONS (VERY HIGH-YIELD)

  • ❌ Not protecting airway (ABSOLUTE)

  • ❌ Vomiting / aspiration risk

  • ❌ AMS / uncooperative

  • ❌ Needs to be awake (or RT at bedside)

Severe → NRB → HFNC → NIPPV → Intubate