19B01 – Robotic prostatectomy (58.6%)
You are seeing a 50-year-old man in the pre-anaesthetic clinic.
He is scheduled for robotic-assisted laparoscopic radical prostatectomy in one week’s time. He has type 2 diabetes mellitus and hypertension, and he smokes 10–15 cigarettes a day. Current medications include:
Metformin Empagliflozin Ramipril
Summary – Middle-aged smoker with metabolic syndrome, listed for urgent robotic prostate cancer surgery, that is taking medicines that increase perioperative morbidity if continued.
1- How would you prepare this patient for surgery?
This will be a focussed pre-operative assessment, keeping in mind that this is urgent cancer surgery scheduled for 7 days time. It will include a focussed history, including functional status, Examination including airway assessment, targeted investigations based on findings, and informed consent.
What specific preparation will you advise?
Smoking – smoking cessation advice. Medications – Withhold SGLT2 3 days pre surgery, metformin and ramipril on morning of surgery.
Why will you stop the SGLT2 inhibitors 3 days before? Risk of euglycemic ketoacidosis if continued perioperatively, due to increased ketone production with normal blood sugar.
What are the features of EKA?
Drowsiness, abdominal pain, nausea, vomiting, fatigue, HAGMA on ABG, pH<7.3, HCO3 <15mmol/l, BE <-5, increased plasma ketones. Capillary ketone measurement – above 0.6mmol/l during perioperative period, or above 1.5mmol/l at any other time. (urinary ketones are not helpful). ANZCA SGLT2i Statement
The patient continues to take their SGLT2i, would you cancel the case?
The guidance is that the drug needs to be stopped for 3 days, so I would postpone the case and explain to the patient and surgeon the reason. ANZCA SGLT2i Statement
Why have you chosen to stop their ACEi, what is the current evidence?
My approach is to stop in the morning of surgery and restart as soon as possible afterwards, to prevent intraoperative hypotension and need for BP support. The ACC guidance suggests that it is also a reasonable approach to continue ACEi peri-operatively. ACC guideline
Are there any other investigations you would like for this patient?
FBC – Baseline Hb, Iron studies if anaemia, HBA1C – >69 indicates poor control AAGBI Diabetes Diabetes Society AUS
How to give smoking cessation advice?
AAR framework from ASA – Ask, Advise, Refer. Non-pharmacological support from face to face and quitlines; Pharmacological therapy including Nicotine replacement, Bupropion, Varenicline, clonidine. ANZCA PS12
2 – What are the issues associated with robotic surgery
The main issues are related to limited patient access and specific patient positioning due to the size and setup of the robot, and robotic procedures commonly being prolonged procedures.
What are the issues related to positioning and long duration surgery
Risk of pressure and nerve injury, and impact on patient physiology from steep head down positioning. There is a risk of gastric reflux and ocular injury, and a protected airway and impervious covering over the eyes. There is also a risk of lower limb compartment syndrome, due to vessel compression and hypoperfusion along with compression.
Why is there a risk of lower limb compartment syndrome?
Positioning to achieve maximal access can require hip extension, if this is extreme, this can lead to compression of the iliac vessels impairing perfusion and venous return. Duration of surgery can lead to direct muscle compression, and hypotension for prolonged periods during surgery with the legs elevated will exacerbate any perfusion deficit.
What are the physiological impacts of positioning for robotic surgery
CVS – increased venous return, increased preload. RS – Reduced FRC, atelectasis, CNS – Risk of cerebral oedema, pos-operative confusion or reduced level of consciousness post-op.
What are the implications of restricted access during surgery
Once the robot is in place and the instruments are docked with the machine, there is restricted access to the head, so managing the airway requires undocking of the instruments, which can take several minutes to remove the instruments
What is your intraoperative fluid management plan?
I will avoid hypotonic solutions, and would choose 0.9% NaCl as my crystalloid, balancing intraopertive volume requirements with a desire to minimise risk of cerebral oedema post-op, which would be increased with large volume crystalloid infusion. The relief trial suggested that an overly restrictive fluid strategy is associated with increased AKI, and laparoscopic surgery so I would aim for no more than 10ml/kg on induction, 8ml/kg/hr intraoperatively, and 1.5ml/kg/hr postop.
criticalpressure 