Neonatal hypoglycaemia



  • Introduction 

    Hypoglycaemia is the most common metabolic disorder of the neonate, and occurs in 5-15% of all neonates. Untreated hypoglycaemia has a high mortality rate, and prolonged or severe neonatal hypoglycaemia can result in brain injury and adverse neurological outcomes; which may impact the neonate well into childhood.

    During intrauterine life, the neonate receives a continuous supply of glucose from the placenta via the umbilical cord. After birth, the umbilical cord is cut and the glucose supply ceases. This, coupled with a transient increase in insulin production cause a drop in blood sugar levels. Immediately after birth, the neonate must adapt and stimulate its own glucose supply with the assistance of enteral feeds (or intravenous fluids if the newborn is unable to feed).

    Even with immediate commencement of breastfeeding/formula feeding/intravenous glucose, there is an expected period of less than 72 hours post-birth in which the glucose levels fluctuate in the neonate. The balance of glucose supply and glucose utilisation in the neonate is impacted by various risk factors and/or underlying conditions.

    When there is an imbalance between glucose supply and glucose utilisation, the neonate may experience hypoglycaemia – which is defined as a blood glucose measurement of below 2.6mmol/L

    Aim

    This guideline will provide information about the risk factors, clinical signs, investigations, and treatmentof neonatal hypoglycaemia.  

    Definition of terms

    Blood glucose level (BGL):  Blood glucose measurement from a bedside glucometer, which is less accurate at low readings.  

    Capillary blood gas (CBG): blood test less invasive than arterial blood gas collected from infant heel, see here for collection instructions

    Hypoglycaemia: A TBG or BGL below 2.6mmol/L

    True blood glucose (TBG): Blood glucose measurement from laboratory or blood gas analyser, the most accurate reading of a blood glucose 

    Risk Factors

    Most neonates with hypoglycaemia are initially asymptomatic, and therefore, early detection of hypoglycaemia is based on surveillance of neonates who have risk factors for hypoglycaemia.

    Risk factors should be assessed on admission, and a blood glucose level (BGL) ordered if the neonate has 1 or more risk factors. 

    Table one: Risk factors include, but are not limited to

    Maternal Factors

    • Maternal diabetes
    • Maternal medication use – i.e. Beta Blockers

    Weight outside normal parameters

    • Small For Gestational Age (SGA) less than 10% Percentile 
    • Large for Gestational Age (LGA) greater than 90% Percentile
    • Intrauterine Growth Restriction (IUGR)

    Premature birth

    • Less than 37 Weeks Gestational Age (GA)

    Inborn errors of metabolism

    • Glucose-6-phosphate dehydrogenase deficiency, G6PD
    • Fatty acid oxidation disorders
    • Glycogen Storage Disease

    Congenital disorders

    • Beckwith- Wiedemann syndrome
    • Congenital hyperinsulinism
    • Congenital hormone deficiencies 
    • Congenital adrenal hyperplasia

    Perinatal stress

    • Respiratory distress, hypoxia, asphyxia   
    • Hypothermia
    • Sepsis

    Nil by mouth

    • Lack of IV Fluids
    • Disruption of IV Fluids due to PIVC issues

    Intake issues

    • Fasting
    • Poor suck
    • Vomiting

    Assessment Clinical Signs

    Neonatal hypoglycaemia is frequently asymptomatic and only detected when BGL testing is performed due to risk factors identified. Clinical signs of neonatal hypoglycaemia may also be shared or similar to the clinical signs of other conditions such as sepsis of asphyxia. 

    Therefore, if a neonate is presenting with clinical signs, it is important to get a true blood glucose (TBG) via a capillary blood gas (CBG) as soon as possible for diagnosis and treatment. 

    Clinical signs of hypoglycaemia:

    Central nervous system excitation:

    • Jitteriness
    • High-Pitched Cry
    • Seizures

    Central nervous system depression:

  • Lethargy
  • Apnoea
  • Poor Feeding
  • Investigations 

    All neonatal admissions presenting with risk factors for hypoglycaemia should have a CBG or a TBG on admission or if there is any clinical signs of hypoglycaemia. Depending on the result, a plan can be discussed with the medical team.

    A TBG should be taken as a capillary blood gas (CBG) for an instant result, when clinical signs are noted, so the potential hypoglycaemia can be treated as quickly as possible.

    A capillary bedside glucometer reading is unreliable at low readings; hence it is important to confirm that the TBG is less than 2.6 mmol/L which can be done by CBG.

    Glucose Infusion Rate (GIR/GUR)

    The Glucose Infusion Rate (GIR) is a measurement of how much glucose (as mg/kg/min) a neonate is receiving. When a neonate has hypoglycemia, their GIR should be calculated to make sure they are receiving an adequate dose of glucose.

    Initially these ranges can be used as a guide, but they can be increased if hypoglycemia persists.

    Term Neonates: 4-6mg/kg/min

    Premature Neonates: 6-8mg/kg/min

    The Glucose Delivery Calculator (NICU Tools) allows you to calculate the GIR of the neonate – including IV and enteral intake. 

    Table two: Parenteral nutrition glucose concentrations

    Standard TPN solutions used in Butterfly Ward:  
    N1 100g/L Glucose = 10% Glucose
    N2 125g/L Glucose = 12.5% Glucose
    N3 200g/L Glucose = 20% Glucose

     

    If a neonate requires greater than 10mg/kg/min of glucose to keep TBG greater than 2.6mmol/L, hyperinsulinism should be suspected and the priority blood tests (below) should be taken.  

    Additional tests to establish causes

    Further blood tests are required if it is suspected that the hypoglycaemia has an underlying cause.

    BGL done via a glucometer is ordered as a POCT (point of care test) and can be done by nursing staff. The result is then entered either via the Manage Labs tab or in the Hub.  

    Medical Staff must order all other tests, including CBG, prior to collection. In EMR the IP Hypoglycaemia Order Set includes picture of vials and which tests to order. 

    The following blood tests should be done while the neonate is hypoglycaemic. Appropriate tubes and amounts indicated in brackets. Serum Gel (Brown); Fluoride Oxalate (Yellow); Lithium Heparin (Orange). These samples should be venous or arterial, capillary specimens are not suitable.

    Urine – first voided urine after hypoglycaemic episode, requesting glucose, ketones, reducing substances and amino and organic acids

    Support non-pharmacological interventions to minimise pain and discomfort (wrapping, comfort care, and sucrose if appropriate) should be provided during blood tests.  

    Table three: Testing

    Priority Blood Tests (Medical staff MUST order these tests prior to collection)

    True Glucose

    (Yellow/Brown, 0.3mL)

    Insulin

    (Brown, 0.5mL, Ice)

    Growth Hormone

    (Brown 0.7mL, tested with Cortisol)

    Cortisol

    (Brown, 0.7mL tested with GH)

    Ketone

    (Blood Glucometer, Urine Dipstick)

    Lactate

    (on CBG)  (is this Yellow 0.3mL)

    Additional blood tests

    C-Peptide

    (Brown, 1mL, Ice)

    Ammonia*

    (Orange, 0.5mL, Ice)

    Free Fatty Acids

    (Yellow, 1mL)

    Amino Acids

    (Orange, 1mL, Ice)

    Carnitine

    (Orange, 1mL)

    Liver Function Tests (LFT)

    (Brown, 0.5mL)

     

    See also Specimen Collection handbook

    Treatment

    When a neonate is hypoglycaemic – prompt treatment is the goal. The aim of the treatment is to quickly bring the neonates BGL greater than 2.6mmol/L.

    A successful treatment plan should include identifying and treating causes, underlying aetiology for the hypoglycaemia.

    While treating the neonate’s hypoglycaemia (as per the below flowchart) it is also important to keep them “warm”, “pink”, “sweet” and “calm”.

    • Warm – Hypothermia increases a neonate’s metabolism, using glucose stores, driving hypoglycaemia. It also causes hypoxia, which results in further hypoglycaemia.
    • Pink – Hypoglycaemia results in hypoxia because it reduces surfactant production and vasoconstriction, driving up work of breathing, leading to respiratory distress – which then forms a feedback loop and results in further hypoglycaemia 
    • SweetMaintaining a normal BGL or treating a low/high BGL
    • Calm minimising energy use and stress, both of which significantly impact the above systems

    Refer to the Management of the neonate and/or Preterm infant management guideline for optimising basic care of the neonate

    Increasing IV Glucose Concentrations (for adjusting the glucose infusion rate GIR)

    Fluids with glucose concentration above 12.5% should be administered through a central venous line (either an umbilical catheter or peripherally inserted central catheter) to reduce risk of extravasation/thrombophlebitis.

    As per the RCH’s Paediatric Injectable Guidelines: 

    Intravenous fluid additive calculations to prepare 500 mL.

    The use of a Glucose 50% concentration infusion is via neonatal consultant approval only and administered only within PICU/NICU.

    Glucagon Treatment  

    In hypoglycaemia, a single bolus injection of glucagon can sometimes increase the blood glucose level enough to make further treatment unnecessary.

    A glucagon continuous infusion is the next step once maximum glucose concentration has been reached and the neonate remains hypoglycaemic. 

    • A Glucagon IM stat injection of glucagon 30-100mcg/kg (0.03-0.1mg/kg), should be given when the hypoglycaemic neonate is symptomatic but does not have IV access.
      • If hypoglycaemia persists despite IV fluids, a second dose of 200mcg/kg dose may be given (6-12 hours after first).
      • Some infants of diabetic mothers may require up to 300mcg/kg to a maximum dose of 1mg (total dose, not per kg).
    • A Glucagon IV Continuous Infusion should be commenced only when the neonate remains hypoglycaemic despite having increased the GIR (maximum) with a glucose concentration of 20% at appropriate TFI.
      • Start Glucagon Infusion with 5mcg/kg/hour and adjust according to response up to 20mcg/kg/hr 

    Administering Buccal Glucose 40% Gel

    Glucose 40% Gel can be administered into the buccal space and enters the systemic circulation via the lingual and jugular veins. Administration of buccal glucose should be immediately followed by enteral feeds, has been shown to increase BGL and reduce the need for IV fluids. Studies have shown this is most effective in babies less than 72 hours of age experiencing suspected transient hypoglycaemia. 

    At RCH this treatment is appropriate for babies who have asymptomatic hypoglycaemia and have no IV access and should be followed up with an enteral feed. Buccal glucose should be ordered by a doctor before administration.

    Medication: Oral gel, 15g glucose in 37.5g (Glucose 40%)

    Dose is 200mg/kg (0.5mL/kg) massaged directly into a neonate's buccal space, followed by a feed (breastfeed, EBM or formula) orally or NGT.

    Buccal Administration Procedure

    1. With an oral syringe, measure out 200mg/kg (0.5mL/kg) of 40% glucose gel.
    2. With a gloved hand, using gauze or a large swab – dry both sides of buccal mucosa (inside lips, above gum line and along cheeks).
    3. Using gloved fingers or a large swab massage the gel into the mucosa, splitting the dose between each side. Do not squirt directly into mouth or at back of throat
    4. Commence enteral feed – either breastfeed, EBM or formula.

    Hypoglycemia Flow Chart 2023

    Education and Family Support

    Education for family members regarding hypoglycaemia is an important aspect of the neonate’s holistic care.

    Education may include:

    • Risk factors and causes of neonatal hypoglycaemia
    • Clinical manifestations of neonatal hypoglycaemia
    • Investigations of neonatal hypoglycaemia
    • Basic nursing management to prevent and manage of neonatal hypoglycaemia
    • Medical management of neonatal hypoglycaemia 

    Family-centered care must always be upheld during clinical concerns of the neonate. Communication of a hypoglycaemic event, investigations taken and subsequent results should be discussed with the family when appropriate. Communication with the family can be documented within EMR progress notes.

    Companion documents

    Evidence table

    Click here to view the evidence table.

    Please remember to read the disclaimer.


    The revision of this nursing guideline was coordinated by Rose Wilson, RN, Butterfly Ward, and approved by the Nursing Clinical Effectiveness Committee. Updated February 2023.