5.1 Diabetic + Day surgery Flashcards
Preoperative
- May have taken full dose of insulin and be fasting
May have omitted insulin and be hyperglycaemic
has not attend pre op - unclear of long standing sugar control checked with hba1c
may indicate someone with poor engagement in diabetic care - poor control
Intraop
May be prone to hypoglycaemia
Post op
higher risk of complications
- post op infection
- erratic bgl
A 52-year-old man has been admitted for a tympanoplasty on the morning of surgery. He is a
longstanding insulin-dependent diabetic who has failed to attend the preoperative assessment clinic.
a) What specific issues does this patient’s diabetes present? (30%)
age and comorb
> > Longstanding diabetes, now 52 years old:
• High probability of micro- (retinopathy, neuropathy, nephropathy) and
macrovascular (ischaemic heart disease, cerebrovascular disease)
complications.
A 52-year-old man has been admitted for a tympanoplasty on the morning of surgery. He is a
longstanding insulin-dependent diabetic who has failed to attend the preoperative assessment clinic.
a) What specific issues does this patient’s diabetes present? (30%)
Diabetes
> > Failure to attend preoperative assessment:
• This may be indicative of generalised poor compliance with
medical management, which is associated with a greater burden of
complications of diabetes.
• Need to assess recent control by checking glycosylated haemoglobin
(HbA1c). HbA1c greater than 69 mmol/mol is associated with increased postoperative complications risk. Non-urgent surgery should be cancelled and diabetes management optimised.
- Patient has not had instructions on alteration of insulin regimen and may now be at greater risk of perioperative hypo- or hyperglycaemia.
- Patient may not have starved appropriately preoperatively.
A 52-year-old man has been admitted for a tympanoplasty on the morning of surgery. He is a
longstanding insulin-dependent diabetic who has failed to attend the preoperative assessment clinic.
a) What specific issues does this patient’s diabetes present? (30%)
Admitted on morning of surgery:
Admitted on morning of surgery:
• Limited time to now undertake thorough assessment and investigation.
Still need to make a thorough assessment of symptoms
and signs suggestive of serious vascular or renal comorbidity.
If further investigation and assessment are indicated, non-urgent surgery should be postponed.
b) How should his diabetes be
managed whilst in hospital? (35%)
Each hospital generally has a protocol of how they like to manage insulin dependent diabetics
one example is a variable rate insulin infusion
VRII
Pre op
Patient is commenced on a dextrose infusion with regular blood glucose checks
An insulin infusion is prsescribed and adjusted based on bgl levels
Diabetes team involved - DNS and endocrinologist
Involvement of patient in their care
Intraoperative
If prolonged procedure can continue insulin dex infusion with regular bgl checks
if short procedure can hold and regularly check bgl
Post op
Resume oral diet as soon as tolerated
if patient not taking full diet adjust insulin dose
(consider half long acting )
b) How should his diabetes be
managed whilst in hospital? (35%)
Exogenous insulin is always required for patients who do not produce insulin in order to prevent catabolism, hyperglycaemia and ketosis.
During times of stress such as surgery, the release of pro-catabolic hormones exacerbates this situation further.
Insulin may be given as an infusion, or, for
short periods of starvation and minor surgery, the normal long-acting insulin dose may be relied upon.
Regional anaesthesia and opioids both reduce
catabolic hormone secretion helping to improve metabolic management perioperatively.
It is important to minimise starvation periods in diabetics, both pre- and postoperatively.
b) How should his diabetes be
managed whilst in hospital? (35%)
> > The patient should be first on morning or afternoon list. Should not be on elective evening list as this is likely to lead to excessive starvation time.
> > Monitor capillary blood glucose (CBG) hourly if ‘basal-bolus’ insulin regimen and starvation time is short (one missed meal).
Basal insulin provides continuous insulin release.
Bolus is omitted with missed meal
and then given when eating restarts.
Glucose-containing fluids are to be avoided.
b) How should his diabetes be
managed whilst in hospital? (35%)
If period of starvation is likely to be prolonged (more than one meal) or if
the patient does not use a long-acting inulin, a variable rate intravenous
insulin infusion (VRIII) must be commenced on admission, in combination
with glucose and potassium containing fluid (0.45% saline with 5%
glucose and 0.15% or 0.3% potassium chloride at 25–50 ml/kg/h).
When the patient is ready to eat postoperatively and is not suffering from
nausea or vomiting, a pre-meal bolus should be given at 30–60 minutes
prior to discontinuation of the VRIII to avoid iatrogenic ketoacidosis.
b) How should his diabetes be
managed whilst in hospital? (35%)
> > CBG target 6–10 mmol/l (up to 12 acceptable) for both regimens.
Hourly CBG monitoring for both and if otherwise indicated.
Aim to return to eating and mobilising as soon as possible
c) What are the anaesthetic considerations for tympanoplasty? (35%)
Technique
Monitoring
> > Local or general anaesthetic: local anaesthetic avoids loss of consciousness, which may make monitoring for hypoglycaemia easier in
a diabetic patient.
> > Facial nerve monitoring: if intubated, need to allow paralysis to wear off to facilitate this. Supraglottic airway device use depends on the patient’s
characteristics. Gastroparesis associated with long-standing diabetes may make this choice inappropriate.
c) What are the anaesthetic considerations for tympanoplasty? (35%)
Day case surgery:
need to ensure good analgesia and antiemesis in order to facilitate same day discharge.
Tympanoplasty tends to be emetogenic.
In a diabetic patient, avoidance of nausea and vomiting is even more important in order to facilitate return to normal insulin regimen.
Dexamethasone worsens diabetic control and should be avoided.
Total intravenous anaesthesia may be considered.
Oral analgesia usually sufficient for tympanoplasty, but NSAIDs may not be appropriate in a diabetic patient with renal complications.
c) What are the anaesthetic considerations for tympanoplasty? (35%)
..Hypotensive anaesthesia: optimises surgical field but may be inappropriate in the presence of micro- and macrovascular comorbidities.
> > Nitrous oxide: avoid due to emetogenesis and gas diffusion into middle ear cavity with the potential for disruption of tympanoplasty grafts (either at the time that the nitrous is being administered or postoperatively as it washes out causing negative pressure in the cavity).
> > Optimisation of ventilatory control: low–normal etCO2 required to avoid vasodilatation, which is associated with blood loss and impaired surgical
field.
