o 2 vs n 2 o. whos the bad guy?? yee l. kwan, rn, ccrn dunap, class of 2013 october 22, 2012
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O2 vs N2O. Who’s the bad guy??
YEE L. KWAN, RN, CCRN
DUNAP, CLASS OF 2013
OCTOBER 22, 2012
How many of you…
Always use 100% O2 for emergence?
1 2
50%50%
1. Yes
2. No
I routinely…
Titrate the FIO2 to the lowest amount my patient needs to maintain their baseline sat.
1 2
50%50%
1. Yes
2. No
What’s the point?
By the end of this presentation you should be able to…….
1.Discuss the pros & cons of O2 and N2O use
2.Identify risks for and s/s of O2 toxicity
3.Discuss various methods/techniques to prevent atelectasis in our pts
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
Meyhoff, C.S., Staehr, A. K., & Rasmussen L. S. (2012)
HAZARDS OF O2 THERAPY
• Oxygen toxicity
• Absorption atelectasis*
• Induced hypoventilation
• Fire hazard
• Retinopathy of Prematurity (ROP)
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
Atelectasis….did you know?
Benoit et al. (2002)
I typically….
Use N2O regularly as part of my anesthetic (assuming no contraindications).
1 2 3
33% 33%33%
1. Yes
2. No
3. Depends on who I’m working with that day
I don’t use N2O because…..
1 2 3 4
25% 25%25%25%1. I’m not comfortable
with it
2. I prefer to keep things simple
3. Risk of N&V
4. My preceptors don’t like it
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
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
N20 CONTRAINDICATIONS
ABSOLUTE
Known deficiency of enzyme or substrate in methionine synthase pathway
Gas filled spaces
Increased ICP
RELATIVE
Pulmonary HTN
Prolonged anesthesia >6hrs
1st trimester
High risk PONV
Risk of MI
Do you use recruitment maneuvers during your anesthetics?
1 2 3
33% 33%33%1. Yes
2. Not usually
3. No
When I use a recruitment maneuver I apply pressure to
1 2 3 4
25% 25%25%25%
1. 20cmH2O
2. 30cmH2O
3. 40cmH2O
4. I don’t know. I just squeeze until it feels “about right”
After this presentation I will definitely think about using N2O on my next patient
1 2
50%50%
1. Yes
2. No
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?
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), 28-33.
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), 75-81. doi: 10.1111/j.1399-6576.2010.02334.x
Grocott, H. P. (2008). Oxygen toxicity during one-lung ventilation: is it time to re-evaluate our practice? [Review]. Anesthesiology clinics, 26(2), 273-280, v. doi: 10.1016/j.anclin.2008.01.008
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), 157-169.
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), 329-335.
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: 10.1213/ANE.0b013e3182652a51
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), 832-842.
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), 1313-1319. doi: 10.1097/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), 1089-1095. doi: 10.1213/ANE.0b013e31822ceef8
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