At a glance
There is a rising incidence and prevalence of diabetes mellitus. About 50% of people with diabetes mellitus are unaware of their condition. Patients with diabetes have a higher risk of cardiovascular disease. Patients with diabetes have a higher perioperative risk. They are more likely because of their disease to require surgery and those undergoing surgery are likely to be less well controlled and to have complications from their diabetes.
Hazards and challenges of diabetes mellitus
Patients with diabetes mellitus are at risk of the complications of the disease. It is worth considering these in outline when considering how best to care for patients with diabetes undergoing surgery.
Perioperative risks and complications of diabetes mellitus
It is important in assessing risk of complications in patients with diabetes undergoing surgery to consider the specific type of surgery and anaesthetic technique. There is evidence for higher risk in those with diabetes undergoing surgery.
However, the following risks and observations are worth considering in patients with diabetes undergoing surgery:
Myocardial infarction postoperatively (may be silent, has a greater mortality). There is an increased risk of postoperative acute myocardial infarction for people with diabetes. The myocardial infarction may be silent (no obvious symptoms) and has a greater overall mortality for people with diabetes.
Patients with diabetes mellitus undergoing percutaneous coronary intervention (PCI) are at increased risk for adverse outcomes.
Cardiac arrest as a consequence of autonomic neuropathy.
Patients with diabetes and chronic kidney disease (diabetic nephropathy) have a worse outcome (complications and mortality) even accounting for the increased risk of associated conditions (hypertension, peripheral vascular disease).
Stroke. This is consistent with the generally increased risk in diabetes mellitus, although again the surgical procedure and other risk factors for stroke (for example, smoking, anaesthetic technique) are important.
Problems with lower limb ischaemia. This is consistent with high incidence of peripheral vascular disease.
Heel pressure sores, particularly with peripheral neuropathy. Postoperative wound infection.
Other infections such as chest and urinary infections are more common in those with diabetes. Tuberculosis can occur particularly in elderly patients with diabetes.
Disruption and worsening of control of diabetes (for example, from the stress of surgery, lack of oral intake, postoperative vomiting, etc).
Poor perioperative control of diabetes is associated with unfavorable outcomes.
Poor intraoperative blood glucose control is associated with worse outcome after cardiac surgery in patients with diabetes.
Diabetes mellitus is a risk factor for prolonged intensive care after cardiac surgery.
Pre-surgical estimation of the patient with diabetes
Ensure that diabetes and comorbidities are optimally managed before the procedure.
Establish history of the patient’s diabetes and the state of their control of the diabetes.
To look for complications of diabetes mellitus.
To establish the safest method of anaesthesia and surgery.
It is apparent from a review of the risks of surgery associated with diabetes mellitus that the assessment and reduction of risk require an individual assessment of the particular patient and the surgery being undertaken.
Choice of anaesthetic
Local or general anaesthesia can be used.
Local anaesthesia: Reduces the stress response.
Hypoglycaemia readily detectable with the patient awake.
Postoperative nausea reduced.
Easy postoperative control of diabetes.
Guidance before surgery
Adults with diabetes, going for an operation and other elective procedures need to be provided guidance just before the same so that they do not face any psychological crisis.
In general, emergency or non-elective cases must have blood glucose controlled with insulin, glucose and potassium infusions as above with special attention being given to rehydration before surgery.
Diabetic Ketoacidosis This can present as abdominal pain and vomiting, with the vomiting usually preceding the pain (unlike in the acute abdomen when pain usually precedes vomiting). If diabetic ketoacidosis does not respond to treatment, it should be remembered that the acute abdomen may have triggered diabetic ketoacidosis.
Anaesthesia and surgery in diabetic ketoacidosis are hazardous but occasionally required (eg, for perforated diverticular abscess). For example, there is a risk of cerebral oedema (resulting from swings in serum osmolarity) and the effects of acidosis on ventilation can cause problems.
Hyperosmolar non-Ketotic Diabetic Coma: These patients rarely require surgery but, if required, it ishigh-risk. Heparinisation is usually required.
Lactic acidosis should be suspected when there is acidosis but no ketosis. It can be caused by the effects of biguanides but occurs also in septicaemia, pancreatitis, liver failure and chronic kidney disease.