Abdominal Insufflation Pressures and Flow Rates

[DocMcCoy]

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Since starting my attending gig for my lap cases I’m getting a lot more bradycardia and hypotension with insufflation than I recall in residency. Didn’t pay too much attention to pressures and flow rates then but definitely do now. All of our general surgeons go to a pressure of 15 with a flow rate of 40L/min right off the bat Unless I have a good reason to make them otherwise. I don’t want to make life harder for anybody but damn if I don’t see clinically significant bradycardia and hypotension in most of my cases. Y’all surgeons run flows similar to this? Seems excessive to optimize surgical conditions. Dosent seem to bother my partners but we go through a lot of glyco/atropine/ephedrine and in the wrong patient seems like a bad idea.

 

[deleted875186]

There’s data that lower insufflation pressures and deep neuromuscular block leads to less postop pan. Maybe you could bring it up to the surgery department.

 

[Ronin786]

Those numbers sound similar to what our surgeons use. The only time I had to ask them to turn down pressure was in a gyn case on a super obese in steep trendelenburg. Made ventilation a bit easier (although now that I think about it, it couldn't have made more than a couple cmH2O on my vent).

 

[Hork Bajir]

Not sure about vagal response (would think this has more to do with the rate of insufflation than the final pressure), but small differences in pressure definitely make a big difference in hemodynamics. 12cm H20 might increase your preload and CO (by compressing splanchnic venous capacitance beds, analogous to wearing a pair of MAST trousers), whereas 14-15cm might tank your preload and CO (by causing kinking of the subdiaphragmatic IVC).

If the vagal response is a recurrent issue and you don’t want to ask your surgeons to change practice, maybe include 0.2 of glyco with your induction meds and see if it helps smooth things out?

 

[DM27]

Where I am the Gyn surgeons have a tendency to rocket in insufflation pressures in the 15-20cmH2O range at the start of the case. Compared to the general surgery cases I definitely see a higher incidence of bradycardia and hypotension (however there is some sex bias I am likely not accounting for). Unless I have a strong reason not to, I will do what is said above and give some combination of 0.2mg glyco a few minutes before insufflation and also give some ephedrine with insufflation if I am concerned.

I have not seen much bradycardia since or dealt with any absolute tachycardia, however, the hypotension still occurs in some cases.

You could try talking to them, but it might be tough if all of the people senior to you are happy to deal with silently and have been for years.