Abstract
Background
A protocol exists for the collection of samples to investigate unexplained hypoglycaemia, termed the ‘hypopack’. These packs are kept in Accident and Emergency departments and neonatal special care baby units throughout Northern Ireland and most wards of the Regional Children's Hospital. A retrospective audit of 107 hypopacks received between July 2001 and December 2003 highlighted a number of problems: samples collected when the patient was receiving dextrose, incomplete clinical history provided, insufficient and haemolysed samples received and poor filing of reports in charts. These were addressed by re-designing the request form, updating the protocol and introducing a summative report. The new protocol was introduced in April 2006.
Methods
The aim of this study is to assess whether the revised protocol improved utility of the hypopack. A retrospective re-audit of 100 hypopacks received between April 2006 and May 2007 was performed.
Results
Forty-nine percent of patients were hypoglycaemic (<2.6 mmol/L) compared with 35% in the original audit. In both audits, 33% of laboratory reports were missing from patients' charts. One case of medium-chain acyl-CoA dehydrogenase deficiency, three cases of hyperinsulinism and two endocrine-related cases were identified.
Conclusions
The new hypopack protocol has increased the number of appropriately performed investigations. Provision of information concerning dextrose infusion has assisted the interpretation of the hypopack results.
Introduction
‘Investigating hypoglycaemia during childhood’ was reviewed by Bonham, who recommended that appropriate samples were obtained and processed to assist in clinically managing the patient. 1 Since the early 1990s, the Clinical Biochemistry Department in the Royal Victoria Hospital has prepared and distributed packs containing specimen tubes and request forms for investigating non-diabetic hypoglycaemic episodes in children, termed 'hypopacks'. These packs are used when a child presents with symptoms of suspected hypoglycaemia or a low point-of-care glucose concentration. A prior audit of processing the hypopacks, between 2001 and 2003, identified a number of preanalytical, analytical and postanalytical issues, including insufficient clinical history, lack of dextrose infusion information, haemolysed samples, insufficient and missing samples, inappropriate use of packs and lack of filing of results in patients' notes. 2 These issues were addressed by a committee of laboratory and clinical staff who made recommendations including re-designing the hypopack form to obtain more appropriate clinical history, revising the protocol and providing a summative report. Recommendations were presented to paediatric and emergency medicine staff in the region's hospitals with a plan to re-audit the service. The specimens collected in the original and current hypopack protocol are described in Table 1. The aim of this study is to assess whether the revised protocol improved utility of the hypopack.
Original and current hypopack protocols
*A urine sample must be obtained as soon as possible after the hypoglycaemic episode. Catheterization may be required
Methods
A retrospective re-audit of 100 hypopacks received during April 2006–May 2007 was performed in assessing whether all specimens were reported and analysed; taken when the patient was hypoglycaemic; taken when the schild was receiving dextrose. Charts were reviewed by requesting clinicians to check that summary reports were filed appropriately and the diagnosis of the hypoglycaemic episode.
Results
One hundred hypopacks were received from 57 male and 43 female children. Of the total, 25% presented during the first month of life and 75% presented before their second birthday.
Hypoglycaemia was defined as a laboratory-measured glucose of <2.6 mmol/L. In this re-audit, 49% of patients were found to be hypoglycaemic compared with 35% in the previous audit. The percentage of true hypoglycaemia was greater from the neonatal unit than children's hospital in both the audits (50% versus 35.3% and 66.6% versus 50%). Only 4% of patients had a glucose concentration >5 mmol/L compared with 16% in the previous audit. Previously, 40% of hypopacks from hospitals outside Belfast had no glucose result provided, which was reduced to 2% in this audit (Table 2).
Glucose results and chart review from the audits of 2001–2003 audit 3 and 2006–2007
RJMH, Royal Jubilee Maternity Hospital; RBHSC, Royal Belfast Hospital for Sick Children
In the original audit, 30% of patients from Royal Belfast Hospital for Sick Children and Royal Jubilee Maternity Hospital were receiving dextrose during sample collection, which was reduced to 17% in this audit. The proportion of hypopacks with one or more samples missing was reduced from 33% to 18% in this audit. Measurement of insulin (Abbott IMX, Abbott Diagnostics, Maidenhead, UK) is affected by haemolysis and a similar proportion of samples were unsuitable in both audits (26% and 21%, respectively).
Of the 78% patient notes available, 67% had all reports filed compared to 65% in the previous audit. In the re-audit period, one case of isolated adrenocorticotropic hormone deficiency, three cases of hyperinsulinism in infancy (of which two were transient), one case of medium-chain acyl-CoA dehydrogenase deficiency and one patient with a previous diagnosis of Morquio disease were identified.
Discussion
In Northern Ireland, hypopacks are used to investigate hypoglycaemia in children. They are distributed to all Accident & Emergency Departments in regional hospitals and any paediatric or neonatal wards. Identifying hypoglycaemia is important, so that appropriate management is initiated before permanent neurological damage occurs. Specimens should be collected when the child is hypoglycaemic to provide information concerning intermediate metabolites 1 and other diagnostic markers. The list of investigations in the hypopack was guided using assay availability and clinical need. The National Metabolic Biochemistry Network has prepared a best practice guideline for the investigation of hypoglycaemia. 3 The current protocol has some specimens missing from this recommendation. Ammonia was omitted from the revised pack as it should be collected when a child is encephalopathic irrespective of glucose status. This was reinforced when the revised protocol was presented to clinicians. 4 Non-esterified free fatty acids were not offered in the revised protocol because of unacceptably long turnaround times. Pyruvate was removed as it was not perceived to be clinically useful and difficult to collect. 5,6 Reducing the number of tests and hence volume of blood reduced the number of missing samples and enabled the appropriate use of the small volumes available from neonates.
Hypopacks are designed for investigating suspected hypoglycaemia based on the clinical suspicion or a low point-of-care glucose measurement. The proportion of packs collected when the patient was clearly not hypoglycaemic (glucose >5 mmol/L) was reduced from 16% to only 4% through re-education when the new protocol was presented. The initial large proportion may have represented misuse of the pack for investigating non-hypoglycaemic metabolic disease.
Initial treatment of hypoglycaemia involved giving the patient dextrose, but this information was rarely noted and was required to interpret the insulin result. Specifically asking on the revised request form whether the child was receiving dextrose resulted in a reduction of hypopacks collected on dextrose infusion. The summative report enabled the clinician to conveniently view the results obtained during the hypoglycaemic episode together and decide whether further tests were required.
Presenting the revised hypopack protocol to clinical staff may have accounted, to some extent, for improvement identified in this re-audit. The shared approach of laboratory staff and clinicians in the revision process also assisted this re-audit.
A pre-prepared pack for investigating a condition or symptom requires collaboration and cooperation between clinicians and laboratory staff. Accessiblity of laboratory facilities is considered important when introducing a pack to a general hospital, which may not perform any specialist tests. Rapid transport of samples to referral laboratories is essential to avoid delaying patient management. In summary, an appropriately designed pack should help in reducing unnecessary investigations and provide the clinician with the minimum information required to make reasoned decisions on further investigations without unnecessary venepuncture. 7 The revised hypopack has achieved this by a collaborative approach.
Footnotes
ACKNOWLEDGEMENTS
We would like to thank Mr Brian Sheridan and his staff in the Regional Endocrine Laboratory at Royal Victoria Hospital for their assistance in analysing the insulin, growth hormone and cortisol samples, and Dr Stan Craig for his advice on the neonatal cases.