(This post can be a bit too technical for the non-medical field readers.. i just had to blog this out so that i may refer to this later as a reference.. LEVEL 7 evidence.. hehehe)
I was doing Prof Sara's hand list the other day. It has always been challenging for anaesthetists to provide excellent surgical conditions and at the same time maintaining safe and effective anaesthesia for the patient. ( i dunno whether surgeons do appreciate our efforts for them?) In the particular case of neurotization or brachial plexus injury nerve repair, the surgeons would usually need the minimal usage of muscle relaxation for their nerve stimulation during the repair. The sugery can be very long therefore the issue of balancing between muscle relaxation and tube discomfort that may make the patient gag if the anaesthesia is too light in the middle of the operation.
Traditionally, we would give only one dose of muscle relaxation for intubation and keeping the patient deep under anaesthesia either via increasing the inhalational agent or balancing it with IV Propofol.IN being conservative , we would prefer to keep the patient with a definitive airway which is the ETT. Unfortunately , once the muscle relaxation wear off it would stimulate the airway reflexes making the patient wake up and being uncomfortable. It would be obscene to have patients moving and gagging the tube while the operation is on. However , putting the patient deep with inhalational for many hours may invoke severe post op nausea and vomiting. hehehe a difficult decision ah?Using a laryngeal mask for many hours may not be such a good idea because of the amount of secretion that may build up and precipitate laryngospasm either intra or as one is taking the LMA off.
I tried a slightly non conservative move the other day by putting in LMA proseal and provide IPPV for the patient. NG tube was possible to be passed through thus making me able to channel out the air off the stomach if the IPPV cause the stomach to inflate.I wanted to use LMA SUPREME ( which i find is the most excellent supraglottic airway to use by date) but as usual in UMC- it is not available when you want it!! I did not use a single muscle relaxant for the op therefore there was no way that the surgeons would not stimulate the nerve and making my muscle relaxant as an excuse and pressure !!
Initially i tried to use TCI propofol but unfortunately the infusion kept fissuring my IV access. And guess what? I resorted to the good excellent DEXMEDETOMIDINE which i gave as a small dose infusion to reduce the usage of my inhalational agent which was sevoflurane. I kept the MAC between 0.7-0.8 and my DEX was running at a rate of 0.5-0.7 ic/g/hr. However , i sort of forgot about my BIS until the patient was drapped over which was too late for me to place the sensor! I could have reduced my MAC further if there was BIS on board but i guess ok la tu.. :)
The op took us 6 hours and i kept him on IPPV for the whole period.He was particularly deep and no surgical stimulation as such for the whole duration. The surgeons had a maximal nerve stimulation but of curse the surgery is tedious and micro standard.
Patient was comfortable post op and it was not long too take the Proseal out! with the Dex effect , patient was fairly arousable when stimulated post op! It was excellent anaesthesia on board and i guess should be applied to similar cases in the future!