Sir,
  I can suggest you two methods.
1) You can ask surgeon to do tracheostomy under local anaesthesia prefereblyTUMISSED. Then, you can intubate orally and this tube can be negotiated by surgeon in to lower end when he is ready.

2) You can use MLE Tube  which is very lengthy and smaller in diameter.

                                                Hemanayakulu

Sir,
If you want to use LMA for caradiac surgeries, you can use it with controlled ventilation . But, why you want to ventillate the pt with LMA when regular intubation is comfortable and safe.
                                                                 Hemanayakulu.