Good evening,
Next week I am going to anesthetize an obese female for an endoscopic combined intra-renal surgery.
She is 160cm tall and 142 kg. No others medical issues. She denied OSAS (STOpBang QUESTIONNAIRE LESS THAN THREE). Any previous surgery and so no history about diffucult facemask ventilation and/or laryngoscopy.
She was scheduled 2 weeks ago but I decided to postpone her surgery because of the lack of beds in ICU and, I think, most importatly, the absence of a recovery area in my current hospital. I was scared about extubation, to be honest.
My 1st question is: how do you procede in managing her airway? Is it appropriate to put her to sleep, taken for granted preoxygenation/CPAP, and try with facemask ventilation and so on? Or is it better to start with an Awake FOB due to the fact that in this hospital we have a bronchoscopist available?
2nd: was it sensible to postpone the surgery?
Thank you.
Airway managment in an obese patient
#1
by manuelacruci on Wed, 2015-03-11 18:34
By now you must have safely anaesthetised this patient and we would like to know how you did it.
You were right to cancel her because you felt she needed postop care in ICU/HDU which was not available. Better safe than be sorry.
From the BMI she must be apple shaped. Not all patients with OSA( obstructive Sleep Apnoea) would know they have the problem. their partners are useful in describing their sleep patterns and breathing and apnoea episodes. however, patients with OSA may have associated pulmonary hypertension. this makes these cases challenging. In most patients with BMI in excess of 40 who are apple shaped, I always assume they have OSA when I am anaesthetising them. So your request for HDU was reasonable.
Most obese patients who have good neck movement are generally easy to intubate using the macintosh in a mojority of the cases. A videolaryngoscope (my preference is the C-Mac standard and D-blade) is useful to have.
Mask ventilation is the biggest challenge and I do not do external facial mask ventilation in these patients. After optimum positioning, pre-oxygenation and induction with propofol in adequate doses( 2 to 3mg/Kg), I insert an iGel (size 4 or 5). in most situations ventilation is easy through an iGel. once the ventilation is adequate I give Rocuronium and continue to ventilate and deepen the anaesthetic. After the Rocuronium has taken effect I intubate them often using the standard C-Mac blade with D-Blade on standby.
a 15 degree head up tilt helps as does a slight flexion of the legs on the abdomen, as the second bit relaxes the intraabdomenal pressure making ventilation easier.
Extubation
fully awake, sitting up. Use Sugammadex after monitoring T1/T4 ratios. once the oropharynx has been cleared of secretiions, insert a properly sized airway. As the patient starts to breathe, let the cuff down on the et tube so the patient is inhaling both through the Et tube and through the airway to prevent negative pressure pulomonary oedema. extubate when patient reaches adequate tidal volumes (> 5ml/Kg) and is fully awake.
observe in recovery for 30 minutes,if well I often discharge them back to the ward, except when they have been diagnosed with OSA or I strongly suspect OSA. We do so many obese patients these days that it is not feasible or practical to ask for HDU for all these cases.
I have used awake fibreoptic intubation in a 165 Kg lady with a BMI of 56 posted for total thyroidectomy, who had a goitre that weighed 1400 grams! The AFOI intubation itself was difficult as the tumour had completely altered the anatomy. successfully operated and was in HDU for 2 days before discharge. in the ward she complained of numbness in the lateral part of the thigh( compression of the lateral cutaneous nerve of the thigh due to aft tissue under the inguinal ligament, boatman's syndrome). As a result I did not get a thank you card for my efforts.
Please share what you did in your case, it will be interesting to know.
BW
Dr.S.Radhakrishna