1. Yee l. kwan, rn, ccrn Dunap, class of 2013 October 22, 2012
O2 vs N2O. Who’s the bad guy??
Yee l. kwan, rn, ccrn
Dunap, class of 2013
October 22, 2012

2. How many of you…
Always use 100% O2 for emergence?
Yes No

3. I routinely…
Titrate the FIO2 to the lowest amount my patient needs to maintain their baseline sat.
Yes No

4. What’s the point?
By the end of this presentation you should be able to…….
Discuss the pros & cons of O2 and N2O use
Identify risks for and s/s of O2 toxicity
Discuss various methods/techniques to prevent atelectasis in our pts

5. o2 is good b/c Well, it’s essential to life!
Possible prevention of surgical site infection (SSI)
Can reduce incidence of PONV
Prevention of hypoxia

6. Meyhoff, C.S., Staehr, A. K., & Rasmussen L. S. (2012)

7. Hazards of o2 therapy Oxygen toxicity Absorption atelectasis*
Induced hypoventilation
Fire hazard
Retinopathy of Prematurity (ROP)

8. Atelectasis….did you know?
In 90% of anesthetized pts
Both with spontaneous ventilation and paralysis
Edmark et al. – CT of lungs of anesthetized patients
PEEP – 10 cmH2O
VC maneuver – 40 cmH2O, 7-8s
Benoit et al. – postop atelectasis

9. Atelectasis….did you know?
Benoit et al. (2002)

10. I typically….
Use N2O regularly as part of my anesthetic (assuming no contraindications).
Yes No
Depends on who I’m working with that day

11. I don’t use N2O because….. I’m not comfortable with it
I prefer to keep things simple
Risk of N&V
My preceptors don’t like it

12. N20 is good b/c Has analgesic effects Rapid uptake and elimination
Little cardiac or respiratory depression
Nonpungent
Additive effect with co-administration of other volatile agents
Can speed up the rate of lung collapse for OLV

13. 2nd gas effect…in reverse
Using the 2nd gas effect to speed up emergence
Peyton et al. found
Time to eye opening and extubation were significantly shorter
Partial pressure of Sevo 39% higher

14. N20 Contraindications
Absolute
relative
Known deficiency of enzyme or substrate in methionine synthase pathway Gas filled spaces Increased ICP
Pulmonary HTN Prolonged anesthesia >6hrs 1st trimester High risk PONV Risk of MI

15. Do you use recruitment maneuvers during your anesthetics?
Yes
Not usually No

16. When I use a recruitment maneuver I apply pressure to
20cmH2O
30cmH2O
40cmH2O
I don’t know. I just squeeze until it feels “about right”

17. After this presentation I will definitely think about using N2O on my next patient
Yes No

18. In summary….. Lots of evidence already exists both pro and con
Every patient requires individual consideration
There never is a right or wrong choice
Think about why you do what you do – is there a good rationale?

19. References:
Edmark, L., Kostova-Aherdan, K., Enlund, M., & Hedenstierna, G. (2003). Optimal oxygen concentration during induction of general anesthesia. [Clinical Trial Randomized Controlled Trial]. Anesthesiology, 98(1),
Edmark, L., Auner, U., Enlund, M., Ostberg, E., & Hedenstierna, G. (2011). Oxygen concentration and characteristics of progressive atelectasis formation during anaesthesia. [Research Support, Non-U.S. Gov't]. Acta anaesthesiologica Scandinavica, 55(1), doi: /j x
Grocott, H. P. (2008). Oxygen toxicity during one-lung ventilation: is it time to re-evaluate our practice? [Review]. Anesthesiology clinics, 26(2), , v. doi: /j.anclin
Hedenstierna, G., & Edmark, L. (2010). Mechanisms of atelectasis in the perioperative period. [Research Support, Non-U.S. Gov't Review]. Best practice & research. Clinical anaesthesiology, 24(2),
Hedenstierna, G., & Rothen, H. U. (2000). Atelectasis formation during anesthesia: causes and measures to prevent it. [Review]. Journal of clinical monitoring and computing, 16(5-6),
Meyhoff, C. S., Jorgensen, L. N., Wetterslev, J., Christensen, K. B., & Rasmussen, L. S. (2012). Increased Long-Term Mortality After a High Perioperative Inspiratory Oxygen Fraction During Abdominal Surgery: Follow-Up of a Randomized Clinical Trial. Anesthesia and analgesia. doi: /ANE.0b013e a51
Rothen, H. U., Sporre, B., Engberg, G., Wegenius, G., Hogman, M., & Hedenstierna, G. (1995). Influence of gas composition on recurrence of atelectasis after a reexpansion maneuver during general anesthesia. [Clinical Trial Comparative Study Randomized Controlled Trial Research Support, Non-U.S. Gov't]. Anesthesiology, 82(4),

20. Staehr, A. K. , Meyhoff, C. S. , & Rasmussen, L. S. (2011)
Staehr, A. K., Meyhoff, C. S., & Rasmussen, L. S. (2011). Inspiratory oxygen fraction and postoperative complications in obese patients: a subgroup analysis of the PROXI trial. [Comparative Study Multicenter Study Randomized Controlled Trial Research Support, Non-U.S. Gov't]. Anesthesiology, 114(6), doi: /ALN.0b013e31821bdb82
Vimlati, L., Kawati, R., Hedenstierna, G., Larsson, A., & Lichtwarck-Aschoff, M. (2011). Spontaneous breathing improves shunt fraction and oxygenation in comparison with controlled ventilation at a similar amount of lung collapse. [Comparative Study Research Support, Non-U.S. Gov't]. Anesthesia and analgesia, 113(5), doi: /ANE.0b013e31822ceef8