At this point, I agree with above. Would you rather risk/deal with inadequate ventilation or just put a tube in? Most likely you have already created some trauma/mucosal irritation with either multiple LMA placements or readjustments or playing with the amount of air in the cuff. At that point you have to ask yourself what advantage does an LMA offer over the tube?
If it's for decrease in sore throat then you can throw that out the window. Patient is already "moderately obese," which would be an indication to throw a tube in someone over a BMI of 35, especially if in lithotomy.
I haven't had any one tactic work any better with a less than ideal seated LMA. Obviously ensure the patient is deep enough. If you think the epiglottis is smacked up over the LMA, sometimes I've found more neck extension while pulling the LMA a an inch or two out then shoving it back down works. In one retrospective review of approximately 19,700 anesthetics involving use of an SGA, use of SGA sizes 2 and 3 was associated with increased incidence of SGA failure. So going a size up most likely will be the answer rather than sizing down (uptodate stuff).
Someone is going to comment on using igel (someone always does), but I haven't used those/they're more expensive.
I personally hate LMA's and if there's any chance I'm questioning if its a good fit for the case, I'm throwing in a tube (unless the attending disagrees of course).
