diabetes, surgery and medical illness Flashcards
management of diabetes during surgery - peri op management of BGC depends on factors including (6)
- required duration fasting
- timing of surgery - am or pm
- usual treatment regimen
- prior glycaemia control
- other comorbids
- likelihood that the pt will be capable of self managing their diabetes in the immediate post op period
what must all patients have written on their drug chart on admission
emergency treatment for hypoglycaemia
Use of insulin during surgery:
Elective surgery—minor procedures in patients with good glycaemic control
if usually treated with insulin and good glycaemia control (HbA1C <69 or 8.5%) then adjust usual insulin regimen during operative period
this should be adjusted depending on type of insulin usually prescribed, following details local protocols, monitoring and control of electrolytes, avoidance of hyperchloraemic metabolic acidosis
day before surgery: give usual insulin as normal, other than OD LA insulin analogues which should be given at dose reduced by 20%
Use of insulin during surgery
Elective surgery—major procedures or poor glycaemic control
Patients usually treated with insulin, who are either undergoing major procedures (surgery requiring a long fasting period of more than one missed meal) or whose diabetes is poorly controlled, will usually require a variable rate intravenous insulin infusion (continued until the patient is eating/drinking and stabilised on their previous glucose-lowering medication).
Emergency surgery for pt with T1 and T2D - always check the following before surgery
blood-glucose, blood or urinary ketone concentration, serum electrolytes and serum bicarbonate
if ketones high or bicarbonate low, also check blood gases
if ketoacidosis present, follow recommendations for DKA immediately and delay surgery if possible
if no acidosis, IV f uids + insulin infusion should be started and managed as for major elective surgery - aka variable rate insulin
When insulin is required and given during surgery, the following drugs should be stopped once the insulin infusion is commenced and not restarted until the patient is eating and drinking normally.
acarbose
meglitinides (repaglinide)
SUs
pioglitazone
DDP4 inhibtors (gliptins)
SGLT2i
which drugs can be continued as normal during insulin infusion during surgery
GLP1 receptor agonsits
which drug class needs to be omitted on day of surgery and not restarted until pt is stable
hint - MHRA advice about treatment interruption during hospitalisation for illness/surgery!
SGLT2i
their use during periods of dehydration and acute illness is associated with an increased risk of developing diabetic ketoacidosis.
which 3 drugs can be taken as normal during the whole peri-op period
pioglitazone
DDP2i
GLP1RA
why should SUs always be omitted on the day of surgery until the patient is eating and drinking again.
and how often to monitor BG, and what to do if hyperglycaemia
associated with hypoglycaemia in the fasted state
check capillary BG hourly
if hyperglycaemia occurs, give appropriate dose of SC RA insulin
second dose can be given 2 hours later and consider variable rate insulin infusion if hyperglycaemia persists
If the patient will miss more than one meal or there is significant risk of the patient developing acute kidney injury, metformin hydrochloride should be stopped when the pre-operative fast begins
Why?
Metformin hydrochloride is renally excreted; renal impairment may lead to accumulation and lactic acidosis during surgery
If only one meal will be missed during surgery, and the patient has an eGFR greater than 60 mL/minute/1.73m2 and a low risk of acute kidney injury (and the procedure does not involve administration of contrast media), it may be possible to continue metformin hydrochloride throughout the peri-operative period—just the lunchtime dose should be omitted if the usual dose is prescribed three times a day.
