Morbid obesity and anaesthesia

 

Scenario:

·         40 year old man

·         180kg 170cm BMI+++

·         Not known to any doctors

·         SBO requiring urgent laparotomy

 

Issues:

Overall

·      Major comorbidity + major surgery

·      Risky anaesthetic and surgery

·      Risky intra-op and post-op

Obesity itself

·      Airway: difficulty bag-mask ventilation due to obstruction; difficult intubation due to positioning

·      Breathing: difficulty ventilating due to restriction, difficulty oxygenating due to shunt

·      Circulation: difficult vascular access and BP monitoring

·      Logistics: difficulty positioning and transferring

Secondary pathology

·      Airway and breathing: sleep-disordered breathing

·      Circulation: AF, coronary artery disease, cardiomyopathy, cor pulmonale

·      Other: diabetes, GORD

 

Assessment:

Questions

·      What is the severity of obesity?

·      What secondary pathologies are present?

·      What needs testing?

·      What needs optimizing?

 

 

 

 

What to do pre-op:

-Assessment (HxExIx)

                Severity of illness: evidence of hypovolaemia, sepsis, organ dysfunction

Presence and severity of comorbidities

Prev anaes esp airway

-Optimisation:

                Time to test anything? e.g. sleep studies (?OSA), TTE (?PHTN, RV dysfx)

                Needs review by anyone? e.g. peri-op med

                Need treatment of anything? e.g. diabetes

-Planning for the entire stay:

                People: second anaesthetist to help me, peri-op physician of some sort

                Equipment: hover mat, oxford ramp, HFNP, locked analgesic infusion pumps

                Facilities: HDU

 

Intra-op:

-Pre-induction

                Access: 2 x 18g IV and arterial line

Monitoring: standard + 5 lead ECG + arterial

-Induction: modified rapid-sequence

                2nd anaesthetist!

                Positioning: oxford ramp + HFNP 50L/min highest FiO2

                Say airway plan: 1)video scope size 8 ETT with stylet 2) iGel size 4 3) BMV with red guedel 4) scalpel bougie cric

                Give drugs: alfentanil 15mcg/kg LBW + propofol 2g/kg LBW + rocuronium 1.2mg/kg

-Maintenance

                Anaesthetic: deflurane to minimize uptake

                Analgesia: ketamine 0.3mg/kg + infusion 0.1mg/kg/h + lignocaine 1mg/kg + infusion 1mg/kg/h + titrated fentanyl 0.5mcg/kg + paracetamol 1g + parecoxib 40mg

                Fluid: CSL how much?

-Emergence

                Suction

                Bite block

                Reversal: sugammadex + TOF >0.9 confirmation

                On bed

                Sitting up

                Obeying commands

                Ensure all systems good: airway/breathing/circ/neuro/neuromusc/acid-base/temp

 

Post-op:

-Disposition: HDU due to risk of airway obstruction and death

-Analgesic plan: paracetamol + ketamine infusion + fentanyl PCA +/- rectus sheath catheters + APS referral

-Rectus sheath catheters: load ropiv 0.75% 10mL each, infuse ropiv 0.2% 6mL/h each