Reading: How to Improve Pre-O2 Before Intubation Flashcards
Why has pre-O2 the Pt been criticized?
Pre-O2 potentially causes atelectasis when high FiO2 is delivered. However, in at risk Pt’s the benefits outweigh this possible complication.
What are the initial and most serious life-threating complications associated with difficult airway access?
Hypoxemia and cardiovascular collapse
Why is obesity associated with a reduction in FRC in the supine position?
The supine position decreases FRC (0.8-1.0 L on average) through multiple mechanism, including the lungs’ weights on a rigid chest wall, and the heart and chest wall weights decreasing the transverse chest diameter. Abd contents are also moved upwards, causing a cranial shift of the diaphragm. Anesthetic drugs induce a decrease in muscle tone, resulting in a addition reduction in FRC 0.4-0.5L on average.
What is denitrogenation-related atelectasis?
Atelectasis in the dependent lung areas as a result of Pre-O2. When pure O2 is administered without positive pressure applied, there is an increased risk of denitrogenation-related atelectasis
What end-tidal O2 is commonly adopted as a surrogate for PAO2?
90%
True or False: The benefit of reaching an end inspiratory oxygen fraction of 100% before attempting intubation outweighs the risk of developing atelectatic-related hypoxia in at risk Pt’s
False, an end inspiration oxygen fraction of 90% before intubation should be reached. Otherwise the statement is true according to the article.
True or False: Studies have reported that pre-O2 in the semi-sitting position or in the 25* head-up position can achieve a higher PAO2.
True. It may also prolong the time to hypoxemia in obese Pt’s
True or False: Studies have shown a benefit of applying CPAP with O2 during pre-O2 in morbidly obese Pt’s
True. Compared to O2 alone, CPAP of 10cmH2O + O2 for 5 min increased the time to desturate and resuced the amount of atelectasis following inuntubation. Immediately after intubation, the amount of atelectasis measured by CT was 10% in the O2 only group but only 2% in the O2 + 10 cmH2O PEEP group
What is the aim of NIV (non-invasive ventilation) during pre-O2?
To recruit lung tissue available for gas exchange (ie to open the lung)
Up to what proportion of an obese Pt’s total lung volume can become atelectic following intubation if no positive pressure is provided during pre-O2?
Up to 10%
Did the study show that a recruitment maneuver (RM) after intubation was associated with a higher PaO2?
Yes. A recruitment maneuver performed immediately after intubation was associated with a higher PaO2 both 5 min after intubation and 30 min after intubation in ICU Pt’s. The one best method was described as applying CPAP of 40cmH2O for 30-40 seconds.
What was the conclusion of this article?
Denitrogenation can be associated with resorption-related atelectasis but the benefit of increasing oxygen stores is higher than the risk of developing atelectasis in Pt’s at risk (critically ill, obese, pregnant, Pt’s whom even slight hypoxemia can be life-threatening such as brain or heart diseased Pt’s). In thises, Pt’s the combination of pure O2, NIV, denitrogenation and post-intubation RMs outweighs the potential risk of post intubation atelectasis.
