ASY-805.1: Insulin Tolerance Test. ASY-805.2: Associated Documents. ASY-805.3: Distribution of Documents. ASY-805.4: Review of Document: a b

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1 ASY-805.1: Insulin Tolerance Test ASY-805.2: Associated Documents a b Handbook page task print-out ASY-805.3: Distribution of Documents Copy No Number Location 1 Quality Centre W W232 Laminated Page 4, 5 and G:\Division\NDO\common\ETCProtocols ASY-805.4: Review of Document: Date Signature Next review Sign when read Do not photocopy Document number: ASY-805 Page 1 of 8

2 Table of Contents ASY-805.1: Insulin Tolerance Test...1 ASY-805.2: Associated Documents...1 ASY-805.3: Distribution of Documents...1 ASY-805.4: Review of Document:...1 ASY-805.5: References...3 ASY-805.6: Clinical application...3 ASY : Purpose of test...3 ASY : Indications...3 ASY : Side effects...3 ASY-805.7: Equipment...3 ASY-805.8: Patient preparation for Insulin Tolerance test...4 ASY-805.9: Procedure for Insulin tolerance test...4 ASY : Supervision...4 ASY : Insulin injection...5 ASY : Dosage...5 ASY : Dose schedule...5 ASY : Insulin preparation 20 units/ml...5 ASY : Checklist...5 ASY : Recommendation for sex steroid priming of GH secretion...6 ASY : Indications...6 ASY : Preparation...6 ASY : Protocol...6 ASY : Reference...6 ASY : The Insulin Tolerance Test (ITT)...8 Risks...8 Summary...8 Reference...8 The following documents are referred to in this document and have been checked for consistency: A ACTH... 8 h:\5qualman\assays\0805-insulin tolerance test.doc Do not photocopy Document number: ASY-805 Page 2 of 8

3 ASY-805.5: References a Shah et al, Brit Med J 304: , b Fish HR, Chernow B, O'Brien JT. Endocrine and Neurophysiologic Responses of the Pituitary to Insulin-Induced Hypoglycaemia: A Review. Metabolism 1986,35: ASY-805.6: Clinical application This test can be useful but clinical consultation with an Endocrinologist must precede the test being performed. ASY : Purpose of test a To lower plasma glucose sufficiently to stimulate the secretion of growth hormone, cortisol and ACTH. This requires a 50% drop from baseline values at minutes post insulin and/or a fall of plasma glucose to 2.2mmol or less. b To measure a patient s sensitivity to given dose of insulin. ASY : Indications As a test of hypothalamic-pituitary function. ASY : Side effects Symptomatic hypoglycaemia minutes after insulin is administered. May provoke cerebral or cardiac complications (very rare). ASY-805.7: Equipment a b c d e 1 20g cannula, luer plug, syringes, swabs, needles, syringe with saline, Tegaderm. Labelled tubes, observation chart, timing clock. Normal saline, 2x 10ml amps 50% Dextrose, drawing up cannula, labels and tubes for samples, insulin, gelofusine. Patient information sheets (see ASY :). Medisense or similar POTC glucose analyser. Do not photocopy Document number: ASY-805 Page 3 of 8

4 ASY-805.8: Patient preparation for Insulin Tolerance test A recent ECG is necessary prior to the test at the discretion of the consultant. The patient is fasted on water only for 8 hours overnight (ie. from midnight) and rests in bed throughout the test. The patient should not be receiving any drugs. If the patient is on steroids or insulin, special arrangements regarding the doses of these hormones have to be made. Patient must not have consumed alcohol within 24hr. The tests should not be done if veins are doubtful. At least one good vein is essential. The test should not be done in epileptics, in the very old (70+ yrs), in patients with ischaemic heart disease or important rhythm disorders. See ASY : for sex steroid priming of GH secretion. ASY-805.9: Procedure for Insulin tolerance test a b c d e f g h Insert a 20g cannula into suitable vein and take (-60 ) cortisol and glucose sample and measure glucose on POTC glucose analyser as per manufacturers instructions. See wall chart. Encourage patient to change into a hospital gown (patient can become very clammy). Patient rests 30 minutes. Dilute and draw up insulin as per ASY :. Draw 0 sample Immediately after sampling, IV certified RN injects insulin (see ASY :) followed by 10ml flush with normal saline and the clock is started at the completion of injection. After 120 sample (samples as per table below), give the patient breakfast. Patient must remain resting on bed till after substantial meal. When the patient has stable glucose levels, remove the cannula. Extra glucose monitoring at 5 intervals between sampling is suggested. Samples drawn as follows: Glucose x x x x x x x x GH x x x x x x Cortisol x x x x x x x L.Hep (ml) EDTA (ml) POTC glucose analyser Note: Paediatric Department, Christchurch Hospital has a protocol for ITT in small children. ASY : Supervision a A Physician or Endocrine nurse must maintain continuous supervision throughout the test. A chart must be kept recording pulse and other symptoms eg: sweating, confusion, drowsiness etc. every 5 minutes from the start of the test. If untoward reaction occurs (coma, rapid palpitations, angina etc.) the test should be terminated with infusion of 2x 10ml ampoules 50% dextrose. (5grams dextrose in 10ml). Do not photocopy Document number: ASY-805 Page 4 of 8

5 ASY : Insulin injection ASY : Dosage Soluble insulin is used as a rapid intravenous injection and if 1 unit per ml solution is used, small doses can be dispensed with accuracy. In all cases the dose of insulin must be calculated and checked by the Registrar after consultation with the Consultant Physician. The registrar must observe and supervise the preparation and administration of the insulin dosage. IV insulin shall be given by an IV certified RN over 1 minute, followed by a 10ml flush with normal saline. ASY : Dose schedule a Likely hypopituitary, underweight and not on replacement therapy, also for children under 4yr of age: 0.05 U/kilo body weight b Possible Hypopituitary, children 4-8 years: 0.1 U/kilo c Normals, children older than 8 y: 0.15 U/kilo d Obese patients: 0.2 U/kilo e Acromegalic or giants: 0.3 U/kilo ASY : Insulin preparation 20 units/ml a Equipment i 1 500ml bag Gelofusine ii 100 units/ml actrapid insulin (penfill) iii 1x 20ml syringe iv 1x 1 insulin syringe v 3x needles vi 1 additive label b Method to make 1 unit per ml of solution of insulin/gelofusine: i Draw up 20ml Gelofusine ii Draw up 20 units of Actrapid insulin (0.2ml on Insulin Syringe) iii Add Insulin 20 units to 20ml Gelofusine. iv Complete additive label and attach to syringe. v Calculate patient dose using dosing schedule (see ASY :) vi Withdraw the required dose from the gelofusine/insulin syringe (1 unit/ml ratio). Do not photocopy Document number: ASY-805 Page 5 of 8

6 ASY : Recommendation for sex steroid priming of GH secretion ASY : Indications For male or female children in whom adequacy of GH secretion is being tested. ASY : Preparation As for Arginine, ITT 1 or other GH provocation testing. Patients should be shown to be euthyroid prior to undertaking the test. ASY : Protocol a Oestradiol Valerate 1.0mg ( Progynova ) tabs 1 or 2 daily for 3 successive days just prior to GH testing. b Dose is decided by body weight: less than 20kg use 1.0mg; more than 20kg use tabs 2 daily (2.0mg/day). ASY : Reference JCEM 2000, 85, page Insulin dose is usually increased (0.2 instead of 0.15 U/kg) when done with sex steroid priming. Do not photocopy Document number: ASY-805 Page 6 of 8

7 Name:... DoB... NHI:... Insulin Tolerance Test Or attach hospital label Weight BP P T Check ECG done No meds given No alcohol No hx epilepsy Not 70 yrs + One suitable within 24 hours or heart disease vein IV cannula (18g) inserted 60 min bed rest commenced Test performed by Dr Nurse Time POTC Gluc GH/Cort ACTH Pulse Symptoms glucose Baseline units of insulin diluted with ml of saline Post sampling: Give food and fluids Remain on bed rest until blood sugar level returns to normal range ( ) Remove cannula once normal blood sugar level obtained Discharge home do not drive 2 hours post test. Time Do not photocopy Document number: ASY-805 Page 7 of 8

8 Patient Information ASY : The Insulin Tolerance Test (ITT) Your doctor has requested a special test of your pituitary and adrenal gland function known as an insulin tolerance test (ITT for short). The aim of the test is to measure the hormone response to the stress of a low blood sugar level. The medication insulin is used in people with diabetes to control high blood sugar levels. When given to non-diabetic people it may reduce blood sugar levels to lower than normal. The body recognises that the sugar level is lower than it should be and responds by increasing the production of a number of hormones, which act to increase the sugar level. Two of these are cortisol (produced by the adrenal gland, under control of a hormone called ACTH, which is made by the pituitary gland) and growth hormone (made by the pituitary gland). It has been well established how much cortisol and growth hormone should be made in response to a low blood sugar. Therefore this test will see if your pituitary and adrenal glands are working normally. A fixed dose of insulin will be administered by injection into a vein after having nothing to eat or drink from midnight the previous night, except water. No alcohol is to be consumed within 24 hours of this test. Your blood sugar will soon begin to fall and should reach its lowest point 20 to 40 minutes after the injection. You may feel sweaty, drowsy, shaky, and hungry and have trouble concentrating while your blood sugar is low. These are expected effects. The blood sugar has to fall to less than 2.2 mmol/l for the hormone production to be stimulated. The symptoms are usually short lived and people start to feel better about an hour after the insulin, as the blood sugar starts to rise again. Blood samples for glucose (sugar) and the hormones are taken regularly during this test. You will be monitored closely and fed prior to leaving the Endocrine Test Centre. It is advisable to organise transport to and from the hospital for this test. Risks Provided the test is carefully planned and done by experienced staff, the ITT is a safe test. The unpleasant symptoms last about half an hour and recovery occurs even before eating. It is a good idea to have an extra something to eat later in the day after completion of the test. There are groups of patients who should not have an ITT - people with epilepsy, people who have had strokes and people with known heart disease (heart attacks, angina, and irregular heart rhythms). If you have any of these, please inform your doctor and/or the endocrine test nurses. We routinely do a cardiograph (ECG) to screen for possible unknown heart conditions before performing an ITT. Having a low blood sugar may precipitate an epileptic seizure or a heart attack in susceptible people. The nursing staff are very experienced and know to administer glucose promptly if signs of a very low blood sugar develop. A doctor is always on hand nearby. Serious effects during an ITT are very rare. In a large review of over 6500 tests 1, only 2 cases of coma, 2 cases of seizures and 2 episodes of angina were reported. All reversed promptly on glucose administration. Summary The ITT is used to check your pituitary and adrenal gland function. Growth hormone and ACTH/cortisol are released in response to a low blood sugar You may feel some unpleasant effects of the low blood sugar such as sweating, drowsiness, "the shakes", hunger, poor concentration. These usually last about half an hour Serious side effects such as seizures, coma and angina are very rare (less than 1 in 1000) and are rapidly reversed with glucose Reference Fish HR, Chernow B, O'Brien JT. Endocrine and Neurophysiologic Responses of the Pituitary to Insulin-Induced Hypoglycaemia: A Review. Metabolism 1986,35: Insulin tolerance test Issue date: 8 June 2010 Document number: ASY-805 Page 8 of 8