Mechanical ventilation (main): Difference between revisions

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Modes
==Background==
*Intubation and ventilation typically required for [[respiratory failure]] or airway protection/severe [[altered mental status]]


===Categories of [[respiratory failure|Respiratory Failure]]===
*Type 1 - [[Hypoxemia]]
*Type 2 - [[hypercapnia|Hypercarbia]]
*Type 3 - Perioperative
*Type 4 - [[Shock]]


CPAP
==Patient Positioning<ref>Greenwood J. Good Lung UP or DOWN? Maneuvers to Improve Oxygenation in Acute Respiratory Failure. Updated 7/15/2014. https://umem.org/educational_pearls/2464/.</ref>==
*HOB elevation > 30 degrees
*Reverse trendelenberg at 30 degrees in obese hypoventilaters
*Lateral decubitus for severe unilateral lung disease
**'''G'''ood lung to '''G'''round generally
**Good lung UP in these exceptions:
***Massive [[hemoptysis]] - prevent blood into dependent, good lung
***Large [[abscess]] - pus fills up dependent lung
***Unilateral [[emphysema]] - prevent hyperinflation


- needs spont breathing pt
==See Also==
{{Mechanical ventilation pages}}
{{Related Difficult Airway Pages}}


- not for fatiguing pt
== Calculators ==
{{Aa_Gradient_Calculator}}


- no back up rate
==External Links==
*Vent basics resource: https://emcrit.org/wp-content/uploads/2010/05/Managing-Initial-Vent-ED.pdf


==References==
<references/>


CONTROL MODE
[[Category:Critical Care]]
 
[[Category:Pulmonary]]
- only in OR
 
- machine initiates and delivers breath
 
- fixed rate and TV
 
 
ASSIST CONTROL (AC)
 
- preset rate and TV
 
- pt able to trigger additional breaths
 
 
SYNCH INTERM MANDATORY VENT (SIMV)
 
- preset rate and TV synch to pt effort
 
- for each additional breath triggered by pt- vent delivers variable TV depending on pt effort and condition of lung
 
- because of pt effort- not recommended for tired or septic pt
 
 
PRESSURE SUPP0RT
 
- use with SIMV or PEEP- not AC
 
- preset boost during inspiration of spont gen breath
 
 
GENERAL
 
RR X TV =
 
 
 
 
[[Category:Pulm]]

Latest revision as of 16:32, 21 March 2026

Background

Categories of Respiratory Failure

Patient Positioning[1]

  • HOB elevation > 30 degrees
  • Reverse trendelenberg at 30 degrees in obese hypoventilaters
  • Lateral decubitus for severe unilateral lung disease
    • Good lung to Ground generally
    • Good lung UP in these exceptions:
      • Massive hemoptysis - prevent blood into dependent, good lung
      • Large abscess - pus fills up dependent lung
      • Unilateral emphysema - prevent hyperinflation

See Also

Mechanical Ventilation Pages

Airway Pages

Calculators

A-a O₂ Gradient

Alveolar-arterial (A-a) O₂ Gradient
Parameter Value
Age (years)
FiO₂ (%)
PaCO₂ (mmHg)
PaO₂ (mmHg)
A-a Gradient mmHg
Expected A-a mmHg (age-adjusted normal)
Interpretation
  • Normal A-a gradient ≈ (Age/4) + 4 on room air
  • Elevated A-a gradient suggests: V/Q mismatch, shunt, or diffusion impairment
  • Normal A-a gradient + hypoxia suggests: hypoventilation or low FiO₂
References
  • Formula: A-a = [FiO₂ × (Patm – PH2O)] – (PaCO₂/0.8) – PaO₂
  • Kanber GJ, et al. The alveolar-arterial oxygen gradient in young and elderly men during air and oxygen breathing. Am Rev Respir Dis. 1968;97(3):376-381. PMID 5637791.

External Links

References

  1. ↑ Greenwood J. Good Lung UP or DOWN? Maneuvers to Improve Oxygenation in Acute Respiratory Failure. Updated 7/15/2014. https://umem.org/educational_pearls/2464/.
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