Anaesthesia and analgesia for people having surgical repair of an abdominal aortic aneurysm
Evidence review L
NICE Guideline, No. 156
Anaesthesia and analgesia for people having surgical repair of unruptured and ruptured abdominal aortic aneurysm
Review questions
What is the most effective approach to anaesthesia and/or analgesia in improving surgical outcome in people undergoing i) endovascular repair (EVAR) and ii) open repair of an unruptured abdominal aortic aneurysm?
What is the most effective approach to anaesthesia and/or analgesia in improving surgical outcome in people undergoing i) EVAR and ii) open repair of a ruptured abdominal aortic aneurysm?
Introduction
Repair of abdominal aortic aneurysms (AAAs) is associated with a variety of risks, including bleeding, infection, nerve or spinal damage, as well as cardiovascular, respiratory, gastrointestinal, and renal complications. People undergoing AAA repair often have cardiovascular and respiratory comorbidities, which can increase the incidence and severity of the aforementioned risks. Optimising how anaesthesia and analgesia are used is an important part of minimising the incidence of complications. This review aims to assess the use of local, regional or general anaesthesia and different analgesic regimens in ‘optimising’ surgical outcome amongst people undergoing surgery for unruptured and ruptured AAA.
PICO table
Table 1
Inclusion criteria.
Methods and process
This evidence review was developed using the methods and process described in Developing NICE guidelines: the manual. Methods specific to this review question are described in the review protocol in Appendix A.
Declarations of interest were recorded according to NICE’s 2014 conflicts of interest policy.
A focused search strategy was used to pull in all studies that assessed the effectiveness of perioperatively administered local or regional anaesthesia and/or analgesia compared to general anaesthesia and/or analgesia in ‘optimising’ surgical outcome amongst people undergoing surgery for an AAA. Randomised, quasi-randomised and non-randomised controlled trials were considered for inclusion. Studies were excluded if they:
- were not in English;
- were not full reports of the study (for example, published only as an abstract);
- were not peer-reviewed;
- focused on postoperative anaesthesia and/or analgesia.
Prospective cohort studies were to be considered for inclusion if insufficient trial evidence was identified and if they had sample sizes larger than 500 and were conducted across multiple centres. Full details of the inclusion criteria are available in the review protocol in Appendix A.
Clinical evidence
Included studies
From an initial database of 2,201 abstracts, 116 full-text articles were ordered. Of these 7 studies conducted in people with unruptured AAA met inclusion criteria for this review, whereas no studies were identified relating to ruptured AAA.
An update search was conducted in December 2017, to identify any relevant studies published during guideline development. The search found 222 abstracts; all of which were not considered relevant to this review question. As a result no additional studies were included.
Excluded studies
The list of papers excluded at full-text review, with reasons, is given in Appendix H.
Summary of clinical studies included in the evidence review
Table 2
Summary of included studies.
See Appendix D for full evidence tables.
Quality assessment of clinical studies included in the evidence review
See Appendix F for full GRADE tables.
Economic evidence
Included studies
A literature search was conducted jointly for all review questions by applying standard health economic filters to a clinical search for AAA. This search returned a total of 5,173 citations. Following review of all titles and abstracts, no studies were identified as being potentially relevant to review question 13 or review question 24.
An update search was conducted in December 2017, to identify any relevant health economic analyses published during guideline development. The search found 814 abstracts; all of which were not considered relevant to this review question. As a result no additional studies were included.
Excluded studies
No studies were retrieved for full-text review.
Evidence statements
Use of anaesthesia and analgesia during repair of unruptured AAA general anaesthesia combined with an epidural compared with general anaesthesia alone during elective open repair
Mortality
- Very low-quality evidence from up to 3 RCTs, including up to 400 people undergoing elective open repair of an AAA, could not differentiate levels of in-hospital mortality or 12-month mortality between people who received general anaesthesia combined with an epidural and those who received general anaesthesia alone.
Adverse events
- Very low-quality evidence from up to 4 RCTs, including up to 450 people undergoing elective open repair of an AAA, could not differentiate the postoperative incidence of myocardial infarction, congestive heart failure or general cardiovascular morbidity between people who received general anaesthesia combined with an epidural and those who received general anaesthesia-alone.
- Very low-quality evidence from up to 4 RCTs, including up to 450 people undergoing elective open repair of an AAA, could not differentiate the postoperative incidence of acute respiratory failure or pneumonia between people who received general anaesthesia combined with an epidural and those who received general anaesthesia alone.
- Very low-quality evidence from up to 4 RCTs, including up to 327 people undergoing elective open repair of an AAA, could not differentiate the postoperative incidence of renal failure or renal insufficiency between people who received general anaesthesia combined with an epidural and those who received general anaesthesia alone.
Surgical complications
- Very low-quality evidence from up to 5 RCTs, including up to 327 people undergoing elective open repair of an AAA, could not differentiate the levels of surgical complications between people who received general anaesthesia combined with an epidural and those who received general anaesthesia alone. Moderate quality evidence from 1 RCT, including 40 people undergoing elective open repair of an AAA, reported less need for additional analgesia in people who received general anaesthesia combined with an epidural compared with those who received general anaesthesia alone.
Need for reoperation
- Very low-quality evidence from 1 RCT, including 160 people undergoing elective open repair of an AAA, could not differentiate reoperation rates between people who received general anaesthesia combined with an epidural and those who received general anaesthesia alone.
Resource use
- Very low-quality evidence from up to 2 RCTs, including up to 217 people undergoing elective open repair of an AAA, could not differentiate the duration of postoperative hospital stay or postoperative stay in the intensive care unit between people who received general anaesthesia combined with an epidural and those who received general anaesthesia-alone.
General anaesthesia combined with intrathecal opioid compared with general anaesthesia alone during elective open repair
Mortality
- Very low-quality evidence from 1 RCT of 217 people undergoing elective open repair of an AAA could not differentiate levels of in-hospital mortality between people who received general anaesthesia combined with intrathecal opioid injection and those who received general anaesthesia alone.
Adverse events
- Very low quality evidence from 1 RCT of 217 people undergoing elective open repair of an AAA could not differentiate the postoperative incidence of myocardial infarction or congestive heart failure between people who received general anaesthesia combined with intrathecal opioid injection and those who received general anaesthesia alone.
- Very low quality evidence from up to 2 RCTs, including up to 242 people undergoing elective open repair of an AAA, could not differentiate the postoperative incidence of respiratory depression, acute respiratory failure or pneumonia between people who received general anaesthesia combined with intrathecal opioid injection and those who received general anaesthesia alone.
Anaesthesia and analgesia during elective EVAR
No evidence was identified relating to anaesthesia and/or analgesia during elective EVAR.
Use of anaesthesia and analgesia during repair of ruptured AAA
No evidence was identified relating to ruptured AAA.
The committee’s discussion of the evidence
Interpreting the evidence
The outcomes that matter most
The guideline committee discussed the relative importance of a variety of outcomes and agreed that the following would be useful to their decision-making:
- Mortality
- The adverse events of anaesthesia or analgesia
- Additional surgical interventions or changes to the approach to anaesthesia and/or analgesia
The quality of the evidence
Use of anaesthesia and analgesia during repair of unruptured AAA
The committee noted that the evidence was limited to the comparison of general anaesthesia alone with general anaesthesia with an epidural or an intrathecal opioid. No evidence was found for other combinations of anaesthesia and analgesia. It was considered that some of the evidence may not have been generalisable to the UK context, primarily because of the formulations and doses of the interventions used. This affected the applicability of the evidence. This applicability was further affected by the populations in a number of the studies, which included people other than those undergoing open repair of an AAA, such as those undergoing surgery for aortoiliac occlusive disease, and those undergoing visceral or renal arterial reconstruction requiring abdominal aortic cross-clamping.
The committee noted that only 1 outcome in 1 comparison reached significance (the need for additional analgesia in the comparison of epidural plus general anaesthesia and general anaesthesia-alone), though this was likely a result of low event rates and small sample sizes. For this reason, the committee noted that there is an absence of evidence, not evidence of absence with regard to differences in the effects of the interventions and comparators studied.
No evidence was identified for anaesthesia and/or analgesia in people undergoing EVAR for unruptured AAA. The committee agreed that it was not necessary to draft consensus recommendations as they had recommended that EVAR should not be used to treat unruptured infrarenal aneurysms elsewhere in the guideline.
Use of anaesthesia and analgesia during repair of ruptured AAA
Since no evidence was identified for anaesthesia and/or analgesia in people undergoing any type of repair of ruptured AAA, the committee agreed that it was appropriate to draft consensus recommendations based on their collective skills, knowledge and experiences (discussed in the benefits and harms section below).
Benefits and harms
Use of anaesthesia and analgesia during repair of unruptured AAA
On the whole, the identified evidence relating to elective open repair did not allow the committee to draw many distinctions between the use of general anaesthesia alone, general anaesthesia with an epidural, and general anaesthesia with an intrathecal injection of opioid. However, the committee noted that the addition of an epidural to general anaesthesia was associated with a lower need for additional analgesia compared with the use of general anaesthesia alone. This preference for the addition of an epidural to general anaesthesia was also supported by the committee’s own clinical experience. The superior analgesic effect of adding an epidural has also been demonstrated and accepted in more general terms, such as in abdominal surgery more broadly, and the committee noted that there was no biological reason to expect that this result would be different in this population.
The committee subsequently discussed the possible populations in which the addition of an epidural to general anaesthesia would be contraindicated, but concluded that there were no such populations that could be specified. In the absence of explicit contraindications, possible reasons not to undertake an epidural might include possible side effects (including cardiac, respiratory, or gastrointestinal complications), the failure rate of epidurals, and the need for relatively intensive postoperative management to maximise benefits of an epidural. However, the committee did not feel that these concerns, when properly accounted for in the management of the patient, outweighed the possible benefits of using an epidural in conjunction with general anaesthesia in people undergoing open repair of an unruptured AAA.
The potential complications of epidural mean that some are now trying alternative methods, including the use of wound catheters to apply local anaesthesia, a technique that is being used more and more in abdominal surgery and which some are starting to use in the open repair of unruptured AAAs. However, the group did not feel that they had sufficient evidence or cause to explicitly recommend the use of wound catheters at this point.
No evidence was identified for optimal use of anaesthesia or analgesia in people undergoing elective EVAR. The committee noted that they recommended the procedure should not be performed in elective cases but acknowledged that in some circumstances, such as a hostile abdomen, EVAR may be warranted. In such situations no approach to anaesthesia and/or analgesia is considered superior to another. The committee agreed that it was important to tailor the approach to the individual patient, particularly in the case of people undergoing complex EVAR. They agreed that some important factors that should be considered include the ‘ease’ of the planned surgery, based upon the size, morphology and position of the aneurysm as well as the estimated duration of surgery, the patient’s preference and concerns (for example, general anaesthesia may be preferable to patients who are anxious about being in the operating theatre). The committee agreed any recommendations on the use of anaesthesia or analgesia in people undergoing elective EVAR would be misleading as they had recommended that the procedure should not be performed in elective cases, elsewhere in the guideline.
Use of anaesthesia and analgesia during repair of ruptured AAA
No evidence was identified for the optimal management of anaesthesia and/or analgesia in people having open repair or EVAR of a ruptured AAA.
The committee agreed that the use of general anaesthesia alone is widely accepted as best practice when performing open surgical repair of a ruptured AAA. Furthermore, the committee agreed that the use of epidurals in addition to general anaesthesia is not considered safe or appropriate in the context of ruptured aneurysm. This is for a number of reasons; including a lack of sufficient time to administer an epidural when a patient is losing blood quickly, as well as the fact that people with ruptured AAA are generally not in a condition to tolerate administration of an epidural. The committee agreed that no recommendation was necessary as it is common practice to use anaesthesia alone during open surgery for ruptured AAA.
In the context of EVAR, the committee concluded that the approach of using anaesthesia and/or analgesia should be based primarily on the stability of the patient’s condition. The committee felt that there was a lack of awareness among anaesthetists of the potential for effectively using local infiltrative anaesthesia alone in people undergoing EVAR for an AAA, at least at the start of the procedure. General anaesthesia can lead to loss of sympathetic control and muscle tone, which in patients with a ruptured aneurysm can lead to profound hypotension; for this reason, the use of local anaesthesia alone (at least initially) may be preferable.
Support for the use of local infiltrative anaesthesia alone in people undergoing EVAR for a ruptured AAA also came from a supplementary piece of evidence identified by the committee. A subgroup analysis of an included RCT for the question on EVAR versus open repair in ruptured AAA (IMPROVE) found that people who underwent EVAR for a ruptured AAA under local anaesthesia had a lower mortality (13%) than those who underwent the procedure under general anaesthesia (34%). This translated to a meaningful benefit for local anaesthesia (OR 0.25 (95% CI 0.10 to 0.70)), which the committee agreed may indicate a survival advantage associated with the use of local anaesthesia. However, the committee also acknowledged that this was a non-randomised comparison and there is no further evidence to support this. They also acknowledged that local infiltration alone may be distressing for the patient, or that it may not be feasible in all circumstances.
Cost effectiveness and resource use
No cost-effectiveness evidence was identified for this review area, and it was not prioritised for economic modelling.
Use of anaesthesia and analgesia during repair of unruptured AAA
The committee considered that the use of an epidural in addition to general anaesthesia during open surgical repair is already widespread practice, so recommending their use would have a limited impact on resource use.
Use of anaesthesia and analgesia during repair of ruptured AAA
The committee considered that the use of general anaesthesia alone in people undergoing open repair of a ruptured AAA is already widespread practice, so recommending its use will have a limited impact on resource use. The committee also agreed that the recommendation to consider local infiltrative anaesthesia alone for people having EVAR for ruptured AAA is unlikely to lead to any substantial change in resource use.
Other factors the committee took into account
No other factors were discussed by the committee.
Appendices
Appendix A. Review protocols
Review protocol for review question 13: Anaesthesia and analgesia for people having surgical repair of an unruptured abdominal aortic aneurysm
Table
Systematic reviews of study designs listed below: Randomised controlled trials
Review protocol for review question 24: Anaesthesia and analgesia for people having surgical repair of a ruptured abdominal aortic aneurysm
Table
Systematic reviews of study designs listed below: Randomised controlled trials
Appendix B. Literature search strategies
Clinical search literature search strategy
Main searches
Bibliographic databases searched for the guideline
- Cumulative Index to Nursing and Allied Health Literature - CINAHL (EBSCO)
- Cochrane Database of Systematic Reviews – CDSR (Wiley)
- Cochrane Central Register of Controlled Trials – CENTRAL (Wiley)
- Database of Abstracts of Reviews of Effects – DARE (Wiley)
- Health Technology Assessment Database – HTA (Wiley)
- EMBASE (Ovid)
- MEDLINE (Ovid)
- MEDLINE Epub Ahead of Print (Ovid)
- MEDLINE In-Process (Ovid)
Identification of evidence for review questions
The searches were conducted between November 2015 and October 2017 for 31 review questions (RQ). In collaboration with Cochrane, the evidence for several review questions was identified by an update of an existing Cochrane review. Review questions in this category are indicated below. Where review questions had a broader scope, supplement searches were undertaken by NICE.
Searches were re-run in December 2017.
Where appropriate, study design filters (either designed in-house or by McMaster) were used to limit the retrieval to, for example, randomised controlled trials. Details of the study design filters used can be found in section 4.
Search strategy review questions 13 and 24
Table
Medline Strategy, searched 11th February 2016 Database: Ovid MEDLINE(R) <1946 to January week 1 2016
Health Economics literature search strategy
Sources searched to identify economic evaluations
- NHS Economic Evaluation Database – NHS EED (Wiley) last updated Dec 2014
- Health Technology Assessment Database – HTA (Wiley) last updated Oct 2016
- Embase (Ovid)
- MEDLINE (Ovid)
- MEDLINE In-Process (Ovid)
Search filters to retrieve economic evaluations and quality of life papers were appended to the population and intervention terms to identify relevant evidence. Searches were not undertaken for qualitative RQs. For social care topic questions additional terms were added. Searches were re-run in September 2017 where the filters were added to the population terms.
Health economics search strategy
Appendix C. Clinical evidence study selection
Review question 13 and 24 study selection
Appendix D. Clinical evidence tables
Download PDF (259K)
Appendix E. Forest plots
Epidural plus general anaesthesia versus general anaesthesia-alone/plus placebo during open repair of unruptured AAA
Mortality
Cardiovascular adverse events
Any cardiovascular adverse event
Myocardial infarction
Congestive heart failure
Ventricular tachyarrhythmia
Respiratory adverse events
Acute respiratory failure (prolonged ventilation)
Pneumonia
Renal adverse events
Renal failure
Renal insufficiency
Gastrointestinal adverse events
Gastrointestinal bleeding
Surgical complications
Blood loss
Sepsis
Resource use
Length of stay
Intrathecal opioid plus general anaesthesia versus general anaesthesia-alone during open repair of unruptured AAA
Respiratory adverse events: respiratory depression
Appendix F. GRADE tables
Epidural plus general anaesthesia versus general anaesthesia-alone/plus placebo during open repair of unruptured AAA
Mortality
Any adverse event
Cardiovascular adverse events
Respiratory adverse events
Renal adverse events
Gastrointestinal adverse events
Surgical complications
Need for reoperation
Resource use
Appendix G. Economic evidence study selection
Appendix H. Excluded studies
Clinical studies
Economic studies
No full text papers were retrieved. All studies were excluded at review of titles and abstracts.
Appendix I. Glossary
- Abdominal Aortic Aneurysm (AAA)
A localised bulge in the abdominal aorta (the major blood vessel that supplies blood to the lower half of the body including the abdomen, pelvis and lower limbs) caused by weakening of the aortic wall. It is defined as an aortic diameter greater than 3 cm or a diameter more than 50% larger than the normal width of a healthy aorta. The clinical relevance of AAA is that the condition may lead to a life threatening rupture of the affected artery. Abdominal aortic aneurysms are generally characterised by their shape, size and cause:
- Infrarenal AAA: an aneurysm located in the lower segment of the abdominal aorta below the kidneys.
- Juxtarenal AAA: a type of infrarenal aneurysm that extends to, and sometimes, includes the lower margin of renal artery origins.
- Suprarenal AAA: an aneurysm involving the aorta below the diaphragm and above the renal arteries involving some or all of the visceral aortic segment and hence the origins of the renal, superior mesenteric, and celiac arteries, it may extend down to the aortic bifurcation.
- Abdominal compartment syndrome
Abdominal compartment syndrome occurs when the pressure within the abdominal cavity increases above 20 mm Hg (intra-abdominal hypertension). In the context of a ruptured AAA this is due to the mass effect of a volume of blood within or behind the abdominal cavity. The increased abdominal pressure reduces blood flow to abdominal organs and impairs pulmonary, cardiovascular, renal, and gastro-intestinal function. This can cause multiple organ dysfunction and eventually lead to death.
- Cardiopulmonary exercise testing
Cardiopulmonary Exercise Testing (CPET, sometimes also called CPX testing) is a noninvasive approach used to assess how the body performs before and during exercise. During CPET, the patient performs exercise on a stationary bicycle while breathing through a mouthpiece. Each breath is measured to assess the performance of the lungs and cardiovascular system. A heart tracing device (Electrocardiogram) will also record the hearts electrical activity before, during and after exercise.
- Device migration
Migration can occur after device implantation when there is any movement or displacement of a stent-graft from its original position relative to the aorta or renal arteries. The risk of migration increases with time and can result in the loss of device fixation. Device migration may not need further treatment but should be monitored as it can lead to complications such as aneurysm rupture or endoleak.
- Endoleak
An endoleak is the persistence of blood flow outside an endovascular stent - graft but within the aneurysm sac in which the graft is placed.
- Type I – Perigraft (at the proximal or distal seal zones): This form of endoleak is caused by blood flowing into the aneurysm because of an incomplete or ineffective seal at either end of an endograft. The blood flow creates pressure within the sac and significantly increases the risk of sac enlargement and rupture. As a result, Type I endoleaks typically require urgent attention.
- Type II – Retrograde or collateral (mesenteric, lumbar, renal accessory): These endoleaks are the most common type of endoleak. They occur when blood bleeds into the sac from small side branches of the aorta. They are generally considered benign because they are usually at low pressure and tend to resolve spontaneously over time without any need for intervention. Treatment of the endoleak is indicated if the aneurysm sac continues to expand.
- Type III – Midgraft (fabric tear, graft dislocation, graft disintegration): These endoleaks occur when blood flows into the aneurysm sac through defects in the endograft (such as graft fractures, misaligned graft joints and holes in the graft fabric). Similarly to Type I endoleak, a Type III endoleak results in systemic blood pressure within the aneurysm sac that increases the risk of rupture. Therefore, Type III endoleaks typically require urgent attention.
- Type IV– Graft porosity: These endoleaks often occur soon after AAA repair and are associated with the porosity of certain graft materials. They are caused by blood flowing through the graft fabric into the aneurysm sac. They do not usually require treatment and tend to resolve within a few days of graft placement.
- Type V – Endotension: A Type V endoleak is a phenomenon in which there is continued sac expansion without radiographic evidence of a leak site. It is a poorly understood abnormality. One theory that it is caused by pulsation of the graft wall, with transmission of the pulse wave through the aneurysm sac to the native aneurysm wall. Alternatively it may be due to intermittent leaks which are not apparent at imaging. It can be difficult to identify and treat any cause.
- Endovascular aneurysm repair
Endovascular aneurysm repair (EVAR) is a technique that involves placing a stent –graft prosthesis within an aneurysm. The stent-graft is inserted through a small incision in the femoral artery in the groin, then delivered to the site of the aneurysm using catheters and guidewires and placed in position under X-ray guidance.
- Conventional EVAR refers to placement of an endovascular stent graft in an AAA where the anatomy of the aneurysm is such that the ‘instructions for use’ of that particular device are adhered to. Instructions for use define tolerances for AAA anatomy that the device manufacturer considers appropriate for that device. Common limitations on AAA anatomy are infrarenal neck length (usually >10mm), diameter (usually ≤30mm) and neck angle relative to the main body of the AAA
- Complex EVAR refers to a number of endovascular strategies that have been developed to address the challenges of aortic proximal neck fixation associated with complicated aneurysm anatomies like those seen in juxtarenal and suprarenal AAAs. These strategies include using conventional infrarenal aortic stent grafts outside their ‘instructions for use’, using physician-modified endografts, utilisation of customised fenestrated endografts, and employing snorkel or chimney approaches with parallel covered stents.
- Goal directed therapy
Goal directed therapy refers to a method of fluid administration that relies on minimally invasive cardiac output monitoring to tailor fluid administration to a maximal cardiac output or other reliable markers of cardiac function such as stroke volume variation or pulse pressure variation.
- Post processing technique
For the purpose of this review, a post-processing technique refers to a software package that is used to augment imaging obtained from CT scans, (which are conventionally presented as axial images), to provide additional 2- or 3-dimensional imaging and data relating to an aneurysm’s, size, position and anatomy.
- Permissive hypotension
Permissive hypotension (also known as hypotensive resuscitation and restrictive volume resuscitation) is a method of fluid administration commonly used in people with haemorrhage after trauma. The basic principle of the technique is to maintain haemostasis (the stopping of blood flow) by keeping a person’s blood pressure within a lower than normal range. In theory, a lower blood pressure means that blood loss will be slower, and more easily controlled by the pressure of internal self-tamponade and clot formation.
- Remote ischemic preconditioning
Remote ischemic preconditioning is a procedure that aims to reduce damage (ischaemic injury) that may occur from a restriction in the blood supply to tissues during surgery. The technique aims to trigger the body’s natural protective functions. It is sometimes performed before surgery and involves repeated, temporary cessation of blood flow to a limb to create ischemia (lack of oxygen and glucose) in the tissue. In theory, this “conditioning” activates physiological pathways that render the heart muscle resistant to subsequent prolonged periods of ischaemia.
- Tranexamic acid
Tranexamic acid is an antifibrinolytic agent (medication that promotes blood clotting) that can be used to prevent, stop or reduce unwanted bleeding. It is often used to reduce the need for blood transfusion in adults having surgery, in trauma and in massive obstetric haemorrhage.
Final
Methods, evidence and recommendations
This evidence review was developed by the NICE Guideline Updates Team
Disclaimer: The recommendations in this guideline represent the view of NICE, arrived at after careful consideration of the evidence available. When exercising their judgement, professionals are expected to take this guideline fully into account, alongside the individual needs, preferences and values of their patients or service users. The recommendations in this guideline are not mandatory and the guideline does not override the responsibility of healthcare professionals to make decisions appropriate to the circumstances of the individual patient, in consultation with the patient and/or their carer or guardian.
Local commissioners and/or providers have a responsibility to enable the guideline to be applied when individual health professionals and their patients or service users wish to use it. They should do so in the context of local and national priorities for funding and developing services, and in light of their duties to have due regard to the need to eliminate unlawful discrimination, to advance equality of opportunity and to reduce health inequalities. Nothing in this guideline should be interpreted in a way that would be inconsistent with compliance with those duties.
NICE guidelines cover health and care in England. Decisions on how they apply in other UK countries are made by ministers in the Welsh Government, Scottish Government, and Northern Ireland Executive. All NICE guidance is subject to regular review and may be updated or withdrawn.