Hypoglycaemic emergencies attended by the Scottish Ambulance Service

390 Pages·2015·3.76 MB·English

by  David Fitzpatrick

Hypoglycaemic emergencies attended by the
Scottish Ambulance Service: a multiple
methods investigation.

David Fitzpatrick
Thesis submitted to the University of Stirling for the
Degree of Doctor of Philosophy

School of Nursing, Midwifery and Health

May 2015

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ABSTRACT
Background
Changing service demands require United Kingdom ambulance services to redefine
their role and response strategies, in order to reduce unnecessary Emergency
Department attendances. Treat and Refer guidelines have been developed with this
aim in mind. However, these guidelines have been developed in the absence of
reliable evidence or guiding mid-range theory. This has resulted in inconsistencies in
clinical practice. One condition frequently included in Treat and Refer guidelines is
hypoglycaemia. Therefore this thesis aimed to investigate prehospital hypoglycaemic
emergencies in order to develop an evidence base for future interventions and
guideline development.
Research approach
A pragmatic and inductive applied health services research approach was employed.
Multiple methods were used in a sequential explanatory design. Three linked studies
were undertaken with the results of previous studies informing the development of the
next.
Study one: A scoping review of prehospital treatment of hypoglycaemic events.
Aims: i) To describe the demographics of the patient population requiring ambulance
service assistance for hypoglycaemic emergencies; ii) To determine the extent to
which post-hypoglycaemic patients with diabetes, who are prescribed oral
hypoglycaemic agents (OHA), experience repeat hypoglycaemic events (RHE) after
being treated in the prehospital environment.
Methods: A scoping literature review was conducted using an overlapping retrieval
strategy that included both published and unpublished literature.
Findings: Twenty-three papers and other relevant material were included.
Hypoglycaemia related ambulance calls account for 1.3% to 5.2% of ambulance calls
internationally. Transportation rates varied between studies (25%-73%). Repeat
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hypoglycaemic emergencies are experienced by 2-7% of patients within 48 hours.
There was insufficient detail to determine any relationship between repeat events and
OHA. The low quality of included papers means that the results should be cautiously
interpreted. The safety of leaving patients on OHA at home post hypoglycaemic
emergency is unknown. Consequently patients taking OHAs who experience a
hypoglycaemic emergency should be transported to hospital for observation. There
was a lack of knowledge about the Scottish demographics of the patient population.
Study two: A retrospective cross-sectional observational study of diabetes
related emergency calls.
Aims: To investigate i) the patient demographics and characteristics of hypoglycaemia
related emergency calls; ii) the incidence of repeat hypoglycaemic events; and iii) the
factors associated with emergency calls that result in individuals being left at home.
Methods: A retrospective observational cross-sectional study conducted using Medical
Priority Dispatch System® call data from West of Scotland Ambulance Control Centre
over a 12 month period. Data were extracted on age, gender, dispatch code, time of
call, deprivation category, and immediate outcome (home or hospital). Multiple
regression analysis was used to determine predictors of remaining at home.
Findings: 1319 calls for hypoglycaemia were received. Patient demographics were
similar to the scoping review findings. Most patients remained at home (N = 916 vs N =
380; p < .001). RHE’s were experience by 3.1% within 48 hours, and 10.6% within two
weeks. The most significant independent predictor for patients remaining at home was
a prior call to the ambulance service (OR of 2.4 [95%CI 1.5 to 3.7]). Patients’ reasons
for remaining at home and the causes of subsequent severe events are unknown. It is
likely that non-clinical factors may explain some of this behaviour.
Study 3: Investigating patients’ experiences of prehospital hypoglycaemic care.
Aim: To investigate the experiences of patients who are attended by ambulance
clinicians for a hypoglycaemic emergency.
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Methods: In-depth interviews with adults with diabetes who had recently experienced
a hypoglycaemic emergency treated by ambulance clinicians. Participants were
recruited from Greater Glasgow and Clyde and Lanarkshire Health Board areas. Data
were analysed using Framework Analysis.
Findings: Twenty six patients were interviewed. Three key themes were developed.
Firstly, an explanation for help seeking behaviour; patients’ impaired awareness of
hypoglycaemia as well as the inability of friends and relatives to cope can contribute to
an ambulance call-out. Secondly, the perceptions of ambulance service care; patients
felt the service provided was good; however ambulance clinicians’ advice was
inconsistent. Thirdly, the influences on uptake of follow-up care; patient preferences
for follow-up care were influenced by previous experiences of home, hospital and
primary care. Post-hoc analysis identified three psychological theories that may explain
these findings and provide a useful basis for intervention development: Common
Sense Model (Leventhal et al, 1998); Health Belief Model (Rosenstock, 1966); Ley’s
cognitive hypothesis model of communication (Ley and Llewelyn, 1995; 1981).
Conclusion
Most people treated for severe hypoglycaemia by ambulance clinicians remain at
home and do not follow-up their care. A few experience repeat hypoglycaemic
emergencies. Key causal, but modifiable factors, contributing to this include:- impaired
awareness of hypoglycaemia; inconsistent delivery of ambulance clinician referral
advice; and patients’ perceptions of the costs and benefits of follow-up care.
Ambulance services cannot address all these factors in isolation. The studies in this
thesis have generated an evidence base and identified plausible candidate theories.
This will support the future development of novel interventions to improve severe
hypoglycaemic emergency follow-up.

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Contents
Abstract ......................................................................................................................................... ii
Summary of Figures .................................................................................................................... xii
Summary of tables ..................................................................................................................... xiii
Summary of appendices ............................................................................................................. xiv
Acknowledgments ....................................................................................................................... xv
Declaration ................................................................................................................................. xvi
Personal Statement .................................................................................................................... xvii
CHAPTER 1: An introduction to prehospital emergency care ....................................................... 1
1.1 Overview ....................................................................................................................... 1
1.2 A brief history of prehospital emergency care ............................................................. 1
1.3 The creation of the NHS ambulance service ................................................................. 3
1.4 Education, guidelines and professional registration ..................................................... 4
1.5 Changing demands ........................................................................................................ 6
1.6 Changing role ................................................................................................................ 8
1.7 Treat and Refer ............................................................................................................. 9
1.8 Developing the evidence base for the paramedic profession .................................... 11
1.9 Approach to research in ambulance care ................................................................... 13
1.9.1 Ontological and epistemological foundations of research ........................................ 13
1.9.2 Theoretical frameworks ............................................................................................. 16
1.9.3 Application of theory in research ............................................................................... 18
1.9.4 Deductive and Inductive approach ............................................................................ 20
1.9.5 Strengths and limitations of inductive and deductive approaches ........................... 20
1.10 The use of theory in this thesis ................................................................................... 24
1.11 Methods ...................................................................................................................... 25
1.11.1 Research location and population ........................................................................... 25
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CHAPTER 2: Diabetes .................................................................................................................. 27
2.1 Introduction ................................................................................................................ 27
2.2 Diabetes ...................................................................................................................... 27
2.2.1 Prevalence .................................................................................................................. 31
2.2.2 Symptoms of diabetes mellitus .................................................................................. 33
2.2.3 Diagnosing diabetes ................................................................................................... 34
2.3 Treatment of diabetes ................................................................................................ 36
2.3.1 Type I treatment ........................................................................................................ 36
2.3.2 Type II treatment ....................................................................................................... 37
2.4 Complication of diabetes ............................................................................................ 37
2.4.1 Long-term consequences of hyperglycaemia and hypoglycaemia ............................ 37
2.4.2 Short-term consequences of hyperglycaemia and hypoglycaemia ........................... 39
2.4.3 Immediate consequences of hypoglycaemia ............................................................. 45
2.5 Prehospital management of hypoglycaemia .............................................................. 45
2.5.1 Hypoglycaemia Treat and Refer guidelines ................................................................ 49
2.5.2 Inconsistencies in Treat and Refer guidelines ............................................................ 50
CHAPTER 3: A scoping review to determine the safety of prehospital treatment of
hypoglycaemic events ................................................................................................................. 51
3.1 Introduction ................................................................................................................ 51
3.2 Exploring the literature ............................................................................................... 52
3.2.1 Review types and terminology ................................................................................... 52
3.2.2 Aims of review ............................................................................................................ 61
3.2.3 Scoping review ........................................................................................................... 63
3.3 Identifying the research question ............................................................................... 65
3.4 Identifying relevant studies......................................................................................... 66
3.5 Study selection ............................................................................................................ 67
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3.6 Charting the data ........................................................................................................ 68
3.7 Descriptive summary of results................................................................................... 77
3.7.1 Patient Demographics ................................................................................................ 77
3.7.2 Incidence of OHA induced hypoglycaemia ................................................................ 78
3.7.3 Consequences and causes of OHA induced hypoglycaemia ...................................... 78
3.7.4 Repeat calls for hypoglycaemic events ...................................................................... 79
3.7.5 Transport to hospital .................................................................................................. 79
3.8 Discussion .................................................................................................................... 80
3.8.1 Hypoglycaemia associated with OHA use .................................................................. 82
3.8.2 Repeat calls and OHA ................................................................................................. 82
3.9 Quality of papers ......................................................................................................... 84
3.10 Limitations ................................................................................................................... 85
3.11 Conclusion ................................................................................................................... 85
CHAPTER 4: A retrospective cross-sectional observational study of diabetes related emergency
calls .............................................................................................................................................. 87
4.1 Introduction ................................................................................................................ 87
4.2 Aims ............................................................................................................................. 88
4.3 Methods ...................................................................................................................... 88
4.3.1 Study Design ............................................................................................................... 88
4.3.2 Data sources ............................................................................................................... 89
4.3.3 Setting ........................................................................................................................ 95
4.3.4 Participants ................................................................................................................ 95
4.3.5 Call data ...................................................................................................................... 96
4.3.6 Data sources/analysis ................................................................................................. 98
4.3.7 Multilevel modelling ................................................................................................ 100
4.3.8 Governance and ethics ............................................................................................. 106
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4.4 Section 2: Results ...................................................................................................... 107
4.4.1 Total calls .................................................................................................................. 107
4.4.2 Incidence and type of diabetes related emergency call .......................................... 108
4.4.3 Patient characteristics for diabetes related calls ..................................................... 108
4.4.4 Aim 1: Patient characteristics for hypoglycaemia related calls ............................... 109
4.4.5 Aim 2: Incidence of repeat hypoglycaemia events ................................................. 113
4.4.6 Aim 3: Factors associated with staying at home ..................................................... 114
4.5 Section 3: Discussion ................................................................................................. 116
4.5.1 Patient Characteristics of hypoglycaemic related emergency calls ......................... 118
4.5.2 Age and emergency hypoglycaemic calls ................................................................. 118
4.5.3 Gender and emergency hypoglycaemic calls ........................................................... 119
4.5.4 Time of call ............................................................................................................... 119
4.5.5 Hospital or home – immediate outcome ................................................................. 120
4.5.6 Repeat and recurrent calls for hypoglycaemic events ............................................. 121
4.5.7 Predictors of immediate outcome (ED or Home) .................................................... 122
4.5.8 Strengths and limitations ......................................................................................... 124
4.5.9 Reflexivity in quantitative enquiry ........................................................................... 127
4.5.10 Conclusion .............................................................................................................. 128
CHAPTER 5: Investigating patients’ experiences of prehospital hypoglycaemic care .............. 131
5.1 Introduction .............................................................................................................. 131
5.2 Considerations on research methods ....................................................................... 132
5.2.1 The need for change ................................................................................................ 132
5.2.2 Mixing approaches and methods. ............................................................................ 133
5.2.3 Evolving typology of mixed methods ....................................................................... 134
5.2.4 Fundamental principles of multiple methods .......................................................... 137
5.2.5 Selecting the research method ................................................................................ 140
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5.2.6 The role of the researcher and reflexivity in qualitative research ........................... 145
5.2.7 Study aims ................................................................................................................ 156
5.2.8 Methods ................................................................................................................... 156
5.2.9 Ethics ........................................................................................................................ 160
5.2.10 Caldicott approval .................................................................................................. 161
5.2.11 Data protection ...................................................................................................... 161
5.2.12 Obtaining contact information of potential participants ....................................... 162
5.2.13 Interviewer safety .................................................................................................. 163
5.2.14 Contacting potential participants .......................................................................... 163
5.2.15 Consent .................................................................................................................. 164
5.2.16 Interviews ............................................................................................................... 164
5.2.17 Analysis – applied qualitative research .................................................................. 166
5.3 Findings ..................................................................................................................... 169
5.3.1 Introduction ............................................................................................................. 169
5.3.2 Summary of themes ................................................................................................. 169
5.3.3 Participant demographics ........................................................................................ 169
5.4 General overview ...................................................................................................... 177
5.5 Theme 1: Explanations for help seeking behaviour .................................................. 180
5.5.1 Recognising hypoglycaemia ..................................................................................... 180
5.5.2 Influences of the carer’s perspective ....................................................................... 184
5.5.3 Summary .................................................................................................................. 194
5.6 Theme 2: Perceptions of prehospital emergency care and advice ........................... 194
5.6.1 Ambulance Control Centre (ACC) ............................................................................. 195
5.6.2 “they are a bit of a crutch” ....................................................................................... 198
5.6.3 Unsuccessful ambulance service treatment ............................................................ 200
5.6.4 Perceptions of advice provided by ambulance clinicians ........................................ 201
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5.6.5 Perception of information transfer between services. ............................................ 206
5.6.6 Summary .................................................................................................................. 209
5.7 Theme 3: Influences on uptake of follow-up care .................................................... 210
5.7.1 Experiences of home recovery and care .................................................................. 210
5.7.2 Contextual factors influencing home recovery ........................................................ 215
5.7.3 Summary .................................................................................................................. 218
5.7.4 Hospital recovery and care ...................................................................................... 218
5.7.5 Summary .................................................................................................................. 227
5.7.6 Experiences of diabetes care providers ................................................................... 228
5.7.7 Summary .................................................................................................................. 235
5.8 Discussion .................................................................................................................. 236
5.8.1 Introduction ............................................................................................................. 236
5.8.2 Perception of hypoglycaemia ................................................................................... 236
5.8.3 Considerations of the predictive validity of proposed psychological theories ........ 248
5.8.4 Limitation and Trustworthiness of the qualitative framework approach ................ 261
5.8.5 Conclusion ................................................................................................................ 268
CHAPTER 6: Overall discussion and conclusion ........................................................................ 272
6.1 Key findings ............................................................................................................... 272
6.1.1 A scoping review to determine the safety of prehospital treatment of
hypoglycaemic events ....................................................................................................... 273
6.1.2 A retrospective cross sectional observational study of diabetes related emergency
calls. ................................................................................................................................... 274
6.1.3 Investigating patients’ experiences of prehospital hypoglycaemic care ................. 275
6.1.4 Strengths and limitations ......................................................................................... 276
6.2 Final discussion ......................................................................................................... 282
6.2.1 The diabetes challenge ............................................................................................ 282
6.2.2 Reducing demand on emergency departments ....................................................... 283
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