Anaesthesia in Diabetic patient

Anaesthesia in the Diabetic patientDr Kapila HettiarachchiConsultant AnaesthetistSBSCH- Peradeniya

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Part 1 A questions related to DM

(10th November 1992)A 40-year-old diabetic of 10 years duration presents for routine abdominal surgery.How would you evaluate his fitness for anesthesia? Outline the problems thatcould occur during the intra-operative period.

(Dec 2005) 5.A 70 year old female with a history of diabetes mellitus of 15 years duration presents with a peri anal abscess. Describe your anaesthetic management.

(Nov 2007) 8. A 50 years old male with a long standing history of diabetes mellitus presents for a wound toilet in the left leg. Outline your perioperative management of this patient.

(April 2011) 6. A 45 year old lady with Type 1 diabetes mellitus controlled with insulin requires total abdominal hystetectomy. Describe your anaesthetic management 1st April, 2003A 52 year old diabetic patient who is on short acting oral hypoglycaemic drugs ispresenting for abdominal hysterectomy.Describe the perioperative management.

Type of DMMedicationEnd-organ changes Nature of surgery Urgency of surgeryLevel of glycemic control

To Assess History and Examination

Investigation

Nephropathy • H/o hypertension, swelling of face and body

• Hypertension and its medication

• Urine – Proteins Sugar

• Microalbuminuria on a timed overnight collection.

• B. Urea, S. Creatinine, S. Electrolytes irrespective of age.

• Possible need for suxamethonium as a result of gastroparesis.

• Ensure adequate hydration to reduce postoperative renal dysfunction.


Investigation

IHDCHF and Cardiomyopathy

• Angina or MI

• Breathlessness, swelling of feet

• Poor exercise tolerance

• Oedema feet, enlarged liver, raised JVP, basal crepts, S3/S4

• ECG• X-ray Chest


Investigation

Autonomic neuropathy

• Early satiety, lack of sweating

• Gastroparesis in the form of vomiting, nocturnal diarrhea, abdominal distension.

• Orthostatic hypotension

• Bladder atony and urinary retention

• Impotence• Palpitation• Sensory discomfort of

lower limbs• Resting tachycardia• Irregular pulse• Dense peripheral

neuropathy.

• SBP response to standing: BP(lying) - BP(Standing) (>30 mm Hg)

(Normal is <10 mmHg)

• DBP response to sustained handgrip: Handgrip sustained at 30% of maximum squeeze for upto 5 minute & BP every minute.

• Difference between DBP just before release – Initial DBP.

(Normal is > 16 mmHg)

To Assess History andExamination

Investigation

Autonomicneuropathy

• Valsalva: Ratio of the Longest R-R to the shortest R-R

(Normal is > 1.21)

• Beat-to-beat variation with deep breathing obtunded: Mean of (maximum HR – minimum HR) of 3 cycles of 6bpm (< 5bpm)

(Normal is > 15 bpm)

• HR response to standing obtunded: Ratio of Longest R-R around 30th beat after standing to the Shortest R-R around 15th beat after standing

(Normal is > 1.04)

Autonomic neuropathy predisposes to hypothermia under anaesthesia


Investigation

Retinopathy Vision deterioration Ophthalmologic examination

• Prevent surges in blood pressure, for example at induction, as this might cause rupture of the new retinal vessels.

To Assess History and Examination Investigation

Stiff joint syndrome

• Stiffness in hand joints• Inability to approximate the

palmar surfaces of phalangeal joints.

• “Prayer Sign”• Non-familial short stature• Tight-waxy skin

• X-ray cervical spine to delineate limited atlantoaxial extension.

Difficult intubation


Investigation

Electrolyte & metabolic derangement

- Non-Compliance of drug- Severe infection or

starvation- Poor control in the past

few days/weeks- S/S of hypoglycemia or

ketoacidosis

- ABG and electrolytes

To Assess History and Examination InvestigationStandard of BS Control

- Hyper/Hypoglycemic episodes- Medication and Compliance

• BS (fasting, PP)

• GTT (if required)

• Glycosylated Hb (HbA1c)

Regional blocks

Regional techniques offer some potential Advantages

1. Avoidance of intubation

2. Having an awake patient to warn of impending hypoglycaemia

3. Earlier return to normal eating patterns.

Disadvantages1. Risks of nerve injury higher. Poor patient positioning is

more likely to result in pressure sores that are often slow to heal given poor peripheral blood flow.

2. Combination of LA with epinephrine may pose greater risk of ischemic or edematous nerve injury (or both) in diabetic

3. Document peripheral neuropathykeeps the patients and relatives informed avoids medico-legal hassles later on

Autonomic neuropathy can result in sudden tachycardia, bradycardia, postural hypotension and profound hypotension after central neuraxial blockade.

4. The chances of epidural abscess are also increased.

Airway

Anticipate difficulty in intubation.

Rapid sequence induction

Respiratory Obese Infection Diabetics are prone to all types of infection.

Indeed an infection might actually worsen diabetic control.

Tight glycaemic control will reduce the incidence and severity of infections and is routine practice in the management of sepsis and diabetic foot infections.

Perform all invasive procedures with full asepsis.

Anaesthetic Management

General Principles Avoid hypoglycaemia (under 4mmol/l) as this can cause

irreversible cerebral damage

Avoid severe hyperglycaemia (over 14mmol/l) to minimise dehydration and metabolic upset

Type 1 diabetics need insulin to prevent ketogenesis and “metabolic derangement’’

Aim for a blood glucose between 6 and 10mmol/l

Accurate, easy-to-use glucose monitors, make the practice of “permissive hyperglycaemia” unacceptable given the known outcome benefits of tight control


General Principles First on the operating list to shorten the preoperative fast and

potentially allow normal oral intake later that same day

Tight metabolic control is important for both type 1 and type 2 patients. If control has been tight in the preceding weeks then fluid and electrolyte balance will be essentially normal.

The best marker for recent control is the percentage of glycosylated haemoglobin (HbA1C).

7% indicate good control over 9% and particularly 12%, indicate poor control likely associated electrolyte and water loss.

Microvascular complications are more


Assess control by blood glucose.

Continue all diabetic medication until the day of surgery except: a.) Chlorpropamide (stop 3 days prior as long acting, substitute with a shorter acting sulphonylurea)

b.) Metformin only if major surgery as risk of lactic acidosis c.) Glitazones d.) Long acting insulin – substitute with short/intermediate acting

Measure blood sugar preoperatively – 4 hourly if on insulin, 8 hourly if not

Major or minor - eat within 4 hours of the operation then treat this group as having “Minor” surgery. Otherwise, surgery is “Major”

Pre-medication Prescribe an H2 antagonist such as

ranitidine150mg and

metoclopramide 10mg, at least 2 hours preoperatively

Drugs Induction agents- If autonomic neuropathy

present use more cardiac stable drugs. N.B. Propofol might drop BP drastically

Analgesics- high doses will obtund stress

Muscle relaxants - careful about suxamethonium if renal failure is present

Inhalationals - halothane and sevoflurane, produce greater negative inotropic effects in diabetic patients than in non-diabetic patients

Minor surgery, type 2 diabetes NOT on insulin (diet/ tablet controlled), 1st on list

Preoperative blood sugar <10mmol/l Take normal medication including evening dose

Preoperative blood sugar >10mmol/l Treat as if “Major” surgery

Omit oral hypoglycaemic on morning of surgery

Monitor blood glucose 1 hour preop; intraoperatively if over 1 hour; and 4hourly postop until eating.

Recommence oral hypoglycaemics with first meal

Minor surgery, type 2 diabetes ON insulin/type 1 diabetes, 1st on list

Take normal medication on day prior* Omit morning SC insulin if glucose < 7 mmol/l Give half normal insulin if glucose >7 mmol/l Monitor blood glucose 1 hour preop;

intraoperatively at least once; 2 hourly until eating and then 4 hourly.

Recommence normal SC insulin with first meal

*If taking a long acting insulin, either convert to short/intermediate acting several days prior or ½ the dose the day prior to surgery

Major surgery, all types of diabetes, 1st

on list, infusion pump available: Normal medication on day prior (unless very poorly controlled, in which

case, establish sliding scale 3 days prior)

Day of surgery, omit oral hypoglycaemics/ normal SC insulin

Check blood glucose 1 hour preop; hourly intraop until 4 hours postop; 2 hrly thereafter and 4 hourly once stabilised.

Insulin is the key infusion. With close monitoring, and adjustment according to a sliding scale, there is no absolute requirement for concurrent dextrose containing solutions, as the tendency will be purely towards hyperglycaemia.

However, commonly 5% or 10% dextrose solutions containing 20mmol/l of KCl are infused at a steady rate of 100ml/hr to provide carbohydrate substrate. Titrate the insulin infusion (through a dedicated line with one-way valve) as below.

Blood glucose (mmol/l)

Insulin infusion rate (unit/h)

If poor control* (unit/h) *If glucose not maintained <10mmol/l then increase the rates

<4 0 04.1-9 1 29.1-13 2 313.1-17 3 417.1-28 4 6>28 6 (check infusion

running)8

Postoperatively Check BS Minor Surgery: Restart OHD with first meal Major surgery: Treat as IDDM

When oral diet is resumed, t.d.s soluble insulin 8-12 units before each meal,

restart oral therapy when daily requirement is less than 20 units.

Major surgery, all types of diabetes,1st on list, NO infusion pump available:

Preoperative management, blood glucose testing and postoperative management as previous example.

Start intravenous infusion of 500ml 5% or 10% dextrose solution with insulin and KCL added as below according to blood glucose and potassium measurements

Blood glucose(mmol/l)

Soluble insulin(units per bag)

• Blood potassium

• (mmol/l)

Potassium Chloride (KCL) (mmol per bag)

<4 04-6 5 <3 206-10 10 3-5 1010-20 15 >5 0>20 20

*If blood potassium level unavailable, add 10mmol KCL per bag

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Anaesthesia in Diabetic patient