Improving outcomes in older people undergoing elective ...

Improving outcomes in older people undergoing elective surgery

ABSTRACT Older people have much to gain from surgery, but pose a significant
challenge not only in emergency surgery but also in elective surgery. Despite
significant progress in the care of older surgical patients, they remain more likely
to ‘fail’ pre-assessment and have higher rates of post-operative complications
than younger people. The evidence suggests that this is a consequence of age-
related increases in co-morbidities and reduction in physiological reserve.
Numerous studies have demonstrated improvements in outcome when individual
co-morbidities are appropriately assessed and optimised. However, current
models of care do not allow for the translation of this evidence into routine
clinical practice, particularly in those with complex co-morbidities and functional
dependence. This article explores the reasons for poor outcome in older people
and describes an alternative model of care for the older elective surgical patient.

KEYWORDS Comprehensive geriatric assessment, elderly, elective surgery, older
people, pre-operative

Dhesi J. Improving outcomes in older people undergoing elective surgery. J R Coll Physicians Edinb 2010; 40:348–53

This review is based on a presentation given by Dr Dhesi at the RCPE Care of
the Elderly Symposium on 15 September 2010.

INTRODUCTION

With the changes in demographics and in surgical and
anaesthetic techniques, more and more older people are
undergoing elective surgery. This is apparent across
surgical subspecialties.1–3 The benefits of surgery in the
elderly are comparable to the younger population,
namely improvements in symptom and pain control,
functional status and quality of life.4 Indeed, in hip and
knee arthroplasty in persons aged more than 80 years,
the most dramatic post-operative functional gains have
been demonstrated in the most disabled of patients.5 In
older patients with cancer, although curative surgery
occurs less commonly, the results in terms of 30-day
mortality are similar to younger people.6–8

Despite the benefits seen with surgery in older people,
they are more likely to be considered to have a clinical
profile that is ‘too risky for surgery’, which potentially
reduces their access to effective elective procedures.
Those who have surgery do indeed have a high rate of
complication, with one fifth of patients aged 70 or more
undergoing non-cardiac surgery developing one or more
serious post-operative complication.8–12 Although the
rate of surgical complications in older patients is
comparable with that of younger patients, the rate of
medical complications is much higher. For example, in a
systematic review of colorectal surgery, older people
had significantly more post-operative medical
complications, while there was no significant difference
in anastomotic leaks.8 Furthermore, older people often
tolerate these complications less well than younger patients
as a consequence of a reduction in physiological reserve
seen with ageing and/or co-morbidity. Worryingly, the
occurrence of post-operative complication has been
shown to be more important than pre-operative patient
risk and intra-operative factors in determining survival
after major surgery.13 Not surprisingly, older people have
a longer length of stay than younger people, predominantly
as a result of the post-operative complications, but also
as a result of difficulties in discharge from hospital.7,10,14,15

This article explores the reasons why older people have
a higher chance of adverse post-operative outcome and
describes methods whereby outcomes may be improved.

PREDICTORS OF ADVERSE POSTXOPERATIVE
OUTCOME
Several multivariate studies have shown that the primary
pre-operative risk factor for poor post-operative outcome
is not age but co-morbidity.9,16,17 Cardiac disease, in
particular ischaemic heart disease, heart failure and
arrhythmia, and reduced physiological reserve are the
strongest predictors of post-operative problems.9,16–18,19
Pulmonary disease, dementia, poor nutrition and, more
recently, anaemia have also been implicated.17,20,21
Interestingly, age is an independent predictor of surgical
site infections and respiratory failure but not of cardiac
events or venous thromboembolism.22,23

Cardiac disease is prevalent in the older population, but
in many it may be asymptomatic and/or unrecognised;
silent ischaemia is common in the elderly and in diabetics
or may be masked by poor exercise tolerance. Post-
operative cardiac complications are common and
particularly serious in the elderly with a higher mortality
in the older compared with the younger population.24,25

The other factor consistently identified as an independent
risk factor for adverse outcome is ‘functional reserve’ or
cardiorespiratory/physiological reserve.19 Normal ageing
affects the resting function of many organs such that the
fit older person has a lower functional reserve and ability
to ‘deal’ with physiological stress. However, when pathology
is superimposed on physiological change, then there is a
further reduction in reserve capacity. It is that reserve
capacity that is called upon during times of stress such as
surgery, with increases in metabolic requirements, often in
the setting of a catabolic state (i.e. cancer or inflammatory
processes). In the past surgeons have relied on the ‘end of
the bed test’ (a visual inspection) to assess functional
reserve. More recently, objective measures such as
cardiopulmonary exercise testing (CPET)19,26 and metabolic
equivalents (METs)27 have gained popularity. In a similar
vein, frailty, which may be defined by clinical judgement,
frailty scales or by operational means, is an independent
and additional risk factor for poor outcome.28,29

As it is estimated that 50% of those aged over 75 years
have a limiting chronic condition, most often cardio-
respiratory, metabolic or neurological,30 and as 10–15%
of those aged over 80 years are deemed frail,31 it is
not surprising that this group has the poorest post-
operative outcome.

Taking this evidence into account, it would seem that
post-operative outcomes in older people could be
improved by ensuring that patients are optimised for
surgery. This requires the clinical application of the
evidence base throughout the elective surgical pathway,
targeting those most at risk. In the following sections
these issues are discussed in more detail.


IMPROVING OUTCOMES BY APPLYING THE
EVIDENCE BASE FOR MEDICAL MANAGEMENT
OF THE SURGICAL PATIENT

There is a growing evidence base for the assessment and
peri-operative management of organ-specific disease. In
some specialties this has been summarised into extremely
useful clinical guidelines, such as those from the American
College of Cardiology or the European Society of
Cardiology on peri-operative cardiovascular evaluation
for non-cardiac surgery.32,33 These guidelines summarise
risk assessment, the need for pre-operative investigation
and the evidence base for the use of beta blockers and
statins in user-friendly algorithms. Similarly, the American
College of Physicians has published a guideline on the
risk assessment and management of peri-operative
respiratory complications based on systematic reviews.34
These existing guidelines are very welcome but require
considered application in the context of the older
population. This is because of the prevalence in this
population of multiple co-morbidities, polypharmacy,
issues with compliance and the practical and cost-
related problems of attending multiple appointments for
investigation and review.

Guidelines are less clear, less available and not as easily
applicable in the case of co-morbidities other than
cardiorespiratory disease. For example, it is known that
anaemia on admission results in a higher incidence of
infection, increased risk of peri-operative myocardial
ischaemia and increased 30-day mortality.20,35,36 There is
growing evidence that pre-operative interventions such
as a correction of iron deficiency can reduce the need
for post-operative transfusion.20,37 However, this evidence
base is not well known to the pre-assessment nurses
who routinely see these patients and is therefore not
often taken into account. In other situations the
importance of the context of the problem is not always
understood. For example, the implication of low-grade
anaemia, e.g. in a frail elderly patient with subclinical
ischaemic heart disease, may not be appreciated by
junior surgical staff.

Further difficulties arise in developing and applying
guidelines for the more ‘multidisciplinary’ areas, such as
nutrition. Despite the importance of malnutrition as a
predictor of adverse outcome17,18,23 and the widespread
availability of nutritional assessment tools, it is often
recognised late. Furthermore, as the evidence for timing,
duration and type of intervention is uncertain, a
standardised approach is not applied.

Other issues require close multidisciplinary working, for
example delirium. There is a good evidence base to allow
the pre-operative identification of patients who are at
high risk of post-operative delirium.38–40 However, this risk
is rarely communicated to anaesthetic staff, who could
ensure vigilant intra-operative monitoring and management
(for example, of peri-operative blood pressure lability); to
surgical ward staff, who could ensure that evidence-based
strategies to reduce the severity, duration and impact of
delirium are implemented;41–43 or to old-age psychiatrists,
who could assist in the pharmacological management if
required. Once delirium is established it is often not
recognised and its impact on the patient, in-hospital
mortality and rates of institutionalisation are not
appreciated by surgical staff.44–46 Evidence suggests that
‘hands on’ geriatric input is needed to implement delirium
strategies and to change clinical practice.43,47

In summary, while there is an evidence base for improving
medical management of the surgical patient, it is not easily
applicable to a patient with multiple co-morbidities nor is
it easily accessible to those who provide direct care for
older surgical patients.


IMPROVING OUTCOMES BY CHANGING THE
ELECTIVE CARE PATHWAY

As discussed, some of the major risk factors for adverse
post-operative outcome, namely co-morbidity and
functional reserve, are potentially modifiable. This implies
that careful pre-operative assessment and management
may be the key to preventing post-operative complications.
To achieve this, the pre-assessment process needs to
focus on the recognition of known co-morbidity, the
identification of unrecognised disease and the assessment
of functional reserve. However, it also needs to be taken
as an opportunity to optimise the medical, functional,
psychological and social condition of the patient, in
order to get the patient as ‘fit as possible’ for surgery.

The pre-assessment process can also allow the prediction
of likely post-operative complications, so that surgical
and anaesthetic teams can be prompted to identify
medical complications early and thereby allow a more
planned and standardised approach to the management
of these complications. This will facilitate multidisciplinary
working between surgical, anaesthetic, intensive care and
elderly care teams. The involvement of a geriatrician may
aid a multidisciplinary approach to capacity, consent and
advanced directives. It also allows early discharge
planning with the identification of those who are most
likely to require additional support and/or rehabilitation
in the post-operative phase.

Unfortunately, the prevalent models of care are narrowly
focused on the surgical issue with which the patient
presents. The majority of pre-assessment clinics are
nurse-led, often nurses with extensive surgical
backgrounds but very little elderly care experience. The
nurse uses a proforma and either identifies the patient
as being ‘fit for surgery’ or as requiring further assessment.
If further review is required, the referral is returned to
the general practitioner (for example, for hypertension
control) or to an anaesthetist or medical specialist such
as cardiologist for specialist medical input. Unfortunately,
this results in a significant proportion of patients being,
at best, delayed for surgery and, at worst, not receiving
the necessary surgery.

Surveys and case note reviews suggest that pre-operative
referrals for medical assessment to organ specialist
physicians result in little advice that truly impacts either
on peri-operative management or the outcome of
surgery.48 In one study, 40% of cardiac consultations made
no recommendation other than ‘proceed with surgery’ or
‘cleared for surgery’.49 This suggests that either the
referrals were inappropriate or that the reviewing
physician was focused on the single organ pathology.

Anaesthetists do review patients in pre-assessment clinics,
but often this is for the patient with complex anaesthetic-
related issues. They more often see patients on the day of
surgery with limited medical information. This reduces the
opportunity to make minor intra-operative adjustments
which may have significant clinical implications (for
example, tight control of blood pressure in a patient with
mild cognitive impairment may reduce delirium).

Furthermore, post-operative care on the surgical ward
is most often provided by junior surgical doctors, with
advice from on-call medical teams, despite this being a
high-risk population. The on-call model leads to
fragmented medical care in the critical post-operative
period. Geriatrician opinions are occasionally sought,
but in a reactive manner rather than pre-empting
issues proactively, and often late in the admission.

An alternative model is the ‘POPS’ model (Proactive
care of Older People undergoing Surgery) illustrated in
Figure 1. The hypothesis underlying this model is that
pre-operative comprehensive geriatric assessment
(CGA), which incorporates the prediction of adverse
outcomes, combined with targeted interventions (pre-
and post-operatively), reduces post-operative complica-
tions and hence the length of stay in older people. This
model was established at Guy’s and St Thomas’ Hospital,
London, in 2005, with initial funding from the Guy’s and
St Thomas’ Charity.

The POPS model ensures that the older patient with
medical co-morbidities or functional dependence is
followed throughout the surgical journey by a
multidisciplinary elderly care team. Pre-operatively, the
team uses CGA methodology to assess and optimise the
patient for surgery, to predict unavoidable post-operative
complications, to predict post-operative rehabilitation or
care needs and to communicate these issues with involved
healthcare professionals and families/carers. This allows a
proactive rather than a reactive approach. The team then
follows the patient through to admission and provides
regular medical input, helping the surgical team in the
early identification and standardised management of
medical complications. POPS has established ward-based
multidisciplinary team meetings with an emphasis on early,
safe and effective discharge planning.

Data published from a pre- and post-POPS study
conducted in orthopaedic elective patients demonstrated
reductions in post-operative medical complications
(delirium, pneumonia, pressure sores), improvements in
pain control and mobilisation and reductions in length of
stay.47 As a consequence the POPS service received
mainstream trust funding. Since then the service has
become embedded into the routine care of older people
undergoing elective surgery (as well as expanding to
cover emergency surgery) across all the major surgical
specialties based at this large London teaching hospital.
Staff and patient questionnaires have demonstrated a
high level of satisfaction with the service.

Furthermore, over the past five years, post-operative
outcomes have steadily improved, reflected by routinely
collected data demonstrating that the older, frailer
cohort attending for elective surgery now has a similar
length of stay as a young, fit cohort. This has occurred as
a consequence of pre-operative optimisation resulting in
fewer medical complications, which are recognised
earlier and managed by advice from a single team in a
proactive manner. In addition, the team ensures
appropriate discharge planning and for this a knowledge
base of the local rehabilitation services and the provision
of social services has been invaluable.


___
Figure 1 A model for proactive care of older people undergoing surgery used at Guy’s and St Thomas’ Hospital, London.47

1. Targeting the patient

Referral criteria based on co-morbidities and
functional impairment known to affect post-
operative outcome
Sources:
Surgical referral from outpatient department
• GP referral
• Waiting list screening
• Deferred cases


2. Pre-operative assessment
Multidisciplinary assessment leading to targeted
intervention

>> Medical and nursing
• Comprehensive geriatric assessment
• Medical/nursing risk stratification and optimisation

>> Physiotherapy
• Cardiovascular and respiratory assessment and
intervention
• Falls assessment, muscle strengthening and
balance training
• Pelvic floor training

>> Occupational therapy
• Optimisation of home circumstances
• Timely provision of equipment

>> Social worker
• Provision of services/benefits pre-operatively
• Assessment of potential discharge concerns

3. Hospitalisation

>> Surgical ward rounds by geriatrician and
specialist nurse
• Early and standardised management of post-
operative complications

>> Ward-based multidisciplinary meetings
• Facilitate therapy liaison
• Implement timely discharge planning

>> Education for surgical nursing and medical staff
• Medical issues
• Geriatric giants (immobility, instability,
incontinence and impaired intellect)
• Discharge planning

4. Community
Use of local intermediate-care services
Follow-up
• Medical
• Physiotherapy/occupational therapy
• Health promotion
–––


THE EVIDENCE GAP

The evidence base for improving outcomes in older
people having surgery is growing. However, many
questions with regards to the clinical management of
this population remain unanswered. There are questions
related to the geriatric syndromes, for example, whether
nutritional or physiotherapy interventions for frailty can
reduce its impact as an independent predictor for
adverse post-operative outcome. Then there are
questions regarding medical conditions. One example is
anaemia: Should iron stores be checked in all older
surgical patients and does supplementation improve
clinical outcome? In addition, there are questions that
can be answered only by complex interventions: Can
post-operative delirium be reduced by pre-operative
optimisation in conjunction with intra-operative
interventions? There are questions relating to the
process and cost effectiveness of care such as: Who
should be implementing guidelines? Should it be the pre-
assessment services, primary care services or organ
specialists or should a new specialty of ‘peri-operative
medicine for the elderly’ be considered? And, finally,
how should one organise the education and training of
the workforce in order to meet the needs of this
growing population?


THE FUTURE

Older patients are a high-risk surgical population by
virtue of their associated co-morbidities and reduction
in functional reserve. However, it needs to be recognised
that increasing numbers of older people will require
elective surgery. In order to provide a high-quality and
cost-effective service, different models of care need to
be considered for this population. Methods need to be
developed for translating the existing evidence base for
single organ disease assessment and management into
routine clinical practice for older people with multiple
co-morbidities. It is time to move on from developing
risk assessment tools to developing interventions to
reduce post-operative complications and mortality. In
order to do this, the development of integrated care
pathways needs to be considered, using the skills of
surgical teams, anaesthetic teams, organ specialists and
geriatricians. There is a need for a medical specialty to
take the lead in providing continuity of medical care for
older people having elective surgery. One could argue
that geriatrics is best placed to take this forward.


REFERENCES

1 Klopfenstein CE, Herrmann FR, Michel JP et al. The influence of an
aging surgical population on the anesthesia workload: a ten-year
survey. Anesth Analg 1998; 86:1165–70. doi:10.1097/00000539-
199806000-00005
2 Pofahl WE, Pories WJ. Current status and future directions of
geriatric general surgery. J Am Geriatr Soc 2003; 51:S351–4.
doi:10.1046/j.1365-2389.2003.51347.x
3 Birrell F, Johnell O, Silman A. Projecting the need for hip
replacement over the next three decades: influence of changing
demography and threshold for surgery. Ann Rheum Dis 1999;
58:569–72. doi:10.1136/ard.58.9.569
4 Ethgen O, Bruyere O, Richy F et al. Health-related quality of life in
total hip and knee arthroplasty: a qualitative and systematic review
of the literature. J Bone Joint Surg Am 2004; 86:963–74.
5 Brander VA, Malhotra S, Jet J et al. Outcome of hip and knee
arthroplasty in persons aged 80 years and older. Clin Orthop Relat
Res 1997; 345:67–78. doi:10.1097/00003086-199712000-00011
6 Tan E, Tilney H, Thompson M et al. The United Kingdom
National Bowel Cancer Project: epidemiology and surgical risk in
the elderly. Eur J Cancer 2007; 43:2285–94. doi:10.1016/j.
ejca.2007.06.009
7 Hamel MB, Henderson WG, Khuri SF et al. Surgical outcomes for
patients aged 80 and older: morbidity and mortality from major
noncardiac surgery. J Am Geriatr Soc 2005; 53: 424–429. doi:10.1111/
j.1532-5415.2005.53159.x
8 Colorectal Cancer Collaborative Group. Surgery for colorectal
cancer in elderly patients: a systematic review. Lancet 2000;
356:968–74. doi:10.1016/S0140-6736(00)02713-6
9 Liu LL, Leung JM. Predicting adverse postoperative outcomes in
patients aged 80 years or older. J Am Geriatr Soc 2000; 48:405–12.
10 Polanczyk CA, Marcantonio E, Goldman L et al. Impact of age on
perioperative complications and length of stay in patients
undergoing noncardiac surgery. Ann Intern Med 2001; 134:637–43.
11 Mantilla CB, Horlocker TT, Schroeder DR et al. Frequency of
myocardial infarction, pumonary embolism, deep venous
thrombosis, and death following primary hip or knee arthroplasty.
Anesthesiology2002; 96:1140–6. doi:10.1097/00000542-200205000-
00017
12 Roche JJ, Wenn RT, Sahota O et al. Effect of comorbidities and
postoperative complications on mortality after hip fracture in
elderly people: prospective observational cohort study. BMJ 2005;
331:1374–6. doi:10.1136/bmj.38643.663843.55
13 Khuri SF, Henderson WG, DePalma RG et al. Determinants of
long-term survival after major surgery and the adverse effect of
postoperative complications. Ann Surg 2005; 242:326–43.
14 O’Toole GC, Abuzukuk T, Murray P et al. Elective total hip
arthroplasty in patients aged 85 years and older. Ir Med PPJ 2002;
95:106–7.
15 Marcantonio ER, Goldman L, Orav EJ et al. The association of
intraoperative factors with the development of postoperative
delirium. Am J Med 1998; 105:380–4. doi:10.1016/S0002-
9343(98)00292-7
16 Turrentine FE, Wang H, Simpson VB et al. Surgical risk factors,
morbidity and mortality in elderly patients. J Am Coll Surg 2006;
203:865–77. doi:10.1016/j.jamcollsurg.2006.08.026
17 Leung JM, Dzankic S. Relative importance of preoperative health
status versus intraoperative factors in predicting postoperative
adverse outcomes in geriatric surgical patients. J Am Geriatr Soc
2001; 49:1080–5. doi:10.1046/j.1532-5415.2001.49212.x
18 Neumayer L, Hosokawa P, Itani K et al. Multivariable predictors of
postoperative surgical site infection after general and vascular
surgery: results from the Patient Safety in Surgery Study. J Am Coll
Surg 2007; 204:1178–87. doi:10.1016/j.jamcollsurg.2007.03.022
19 Older P, Hall A, Hader R. Cardiopulmonary exercise testing as a
screening test for perioperative management of major surgery in
the elderly. Chest 1999; 116:355–62. doi:10.1378/chest.116.2.355
20 Myers E, Grady PO, Dolan AM. The influence of preclinical anaemia
on outcome following total hip replacement. Arch Orthopaed
Trauma Surg 2004; 124:699–701. doi:10.1007/s00402-004-0754-6
21 Mangano DT. Perioperative cardiac morbidity. Anesthesiology 1990;
72: 153–84. doi:10.1097/00000542-199001000-00025
22 Rogers SO Jr, Kilaru RK, Hosokawa P et al. Multivariable predictors
of postoperative venous thromboembolic events after general and
vascularsurgery: results from the Patient Safety in Surgery Study. J Am
Coll Surg 2007; 204:1211–21. doi:10.1016/j.jamcollsurg.2007.02.072
23 Gibbs J, Cull W, Henderson W et al. Preoperative serum albumin
level as a predictor of operative mortality and morbidity: results
from the National VA Surgical Risk Study. Arch Surg 1999; 134:36–
42. doi:10.1001/archsurg.134.1.36
24 Detsky AS, Abrams HB, McLaughlin JR et al. Predicting cardiac
complications in patients undergoing non-cardiac surgery. J Gen
Intern Med 1986; 1:211–19. doi:10.1007/BF02596184
25 Cook DJ, Rooke GA. Priorities in perioperative geriatrics. Anesth
Analg 2003; 96:1823–36. doi:10.1213/01.ANE.0000063822.02757.41
26 Smith TB, Stonell C. Cardiopulmonary exercise testing as a
risk assessment method in non-cardiopulmonary surgery:
a systematic review. Anaesthesia 2009; 64:883–93. doi:10.1111/
j.1365-2044.2009.05983.x
27 Eagle KA, Berger PB, Calkins H et al. ACC/AHA Guideline update
for perioperative cardiovascular evaluation for noncardiac
surgery. J Am Coll Cardiol 2002; 39:542–53. doi:10.1016/S0735-
1097(01)01788-0
28 Fried LP, Tangen CM, Walston J et al. Frailty in older adults:
evidence for a phenotype. J Gerontol A Biol Sci Med Sci 2001;
56:146–56.
29 Makary MA, Segev DL, Pronovost PJ et al. Frailty as a predictor of
surgical outcomes in older patients. J Am Coll Surg 2010; 210:901–8.
doi:10.1016/j.jamcollsurg.2010.01.028
30 Office for National Statistics. 2001 Census. Available from: http://
www.statistics.gov.uk/hub/health-social-care/index.html
31 Charles Sturt University. Frailty; a robust approach. Wagga Wagga:
Charles Sturt University; 2010. Available from: http://www.csu.
edu.au/faculty/science/frailty/index.htm
32 Fleisher LA, Beckman JA, Brown KA et al. ACC/AHA 2007
guidelines on perioperative cardiovascular evaluation and care for
noncardiac surgery. Circulation 2007; 116:e418–99. doi:10.1161/
CIRCULATIONAHA.107.185699
33 Poldermans D, Bax JJ, Boersma E. Guidelines for pre-operative
cardiac risk assessment and perioperative cardiac management in
non-cardiac surgery: the Task Force for Preoperative Cardiac Risk
Assessment and Perioperative Cardiac Management in Non-
cardiac Surgery of the European Society of Cardiology (ESC) and
European Society of Anaesthesiology (ESA). Eur Heart J 2009;
30:2769–812.
34 Qaseem A, Snow V, Fitterman N et al. Risk assessment for and the
strategies to reduce perioperative pulmonary complications for
patients undergoing noncardiothoracic surgery: a guideline from the
American College of Physicians. Ann Intern Med 2006; 144:575–80.
35 Hogue CW Jr, Goodnough LT, Monk TG. Perioperative myocardial
ischemic episodes are related to hematocrit level in patients
undergoing radical prostatectomy. Transfusion 1998; 38:924–31.
doi:10.1046/j.1537-2995.1998.381098440856.x
36 Wu WC, Schifftner TL, Henderson WG et al. Preoperative
haematocrit levels and postoperative outcomes in older patients
undergoing noncardiac surgery. JAMA 2007; 297:2481–8.
37 García-Erce JA, Cuenca J, Muñoz M et al. Perioperative stimulation
of erythropoiesis with intravenous iron and erythropoietin
reduces transfusion requirements in patients with hip fracture. A
prospective observational study. Vox Sang 2005; 88:235–4.
doi:10.1111/j.1423-0410.2005.00627.x
38 Marcantonio ER, Goldman L, Mangione CM et al. A clinical
prediction rule for delirium after elective noncardiac surgery.
JAMA 1994; 271:134–9.
39 Kalisvaart KJ, Vreeswijk R, de Jonghe JF et al. Risk factors and
prediction of postoperative delirium in elderly hip-surgery patients:
Implementation and validation of a medical risk factor model. J Am
Geriatr Soc 2006; 54:817–22. doi:10.1111/j.1532-5415.2006.00704.x
40 Freter SH, Dunbar MJ, MacLeod H et al. Predicting post-operative
delirium in elective orthopaedic patients: the Delirium Elderly
At-Risk (DEAR) instrument. Age Ageing 2005; 34:169–84.
doi:10.1093/ageing/afh245
41 Lundström M, Olofsson B, Stenvall M et al. Postoperative delirium
in old patients with femoral neck fracture: a randomized
intervention study. Aging Clin Exp Res 2007; 19:178–86.
42 Stenvall M, Olofsson B, Lundström M et al. A multidisciplinary
multifactorial intervention program reduces postoperative falls
and injuries after femoral neck fracture. Osteoporos Int 2007;
18:167–75. doi:10.1007/s00198-006-0226-7
43 Marcantonio ER, Flacker JM, Wright RJ et al. Reducing delirium
after hip frature: a randomised trial. J Am Geriatr Soc 2001; 49:516–
22. doi:10.1046/j.1532-5415.2001.49108.x
44 Duppils GS, Wikblad K. Patients’ experiences of being delirious.
J Clin Nurs 2007; 16: 810–8. doi:10.1111/j.1365-2702.2006.01806.x
45 Marcantonio ER, Flacker JM, Michaels M et al. Delirium is
independently associated with poor functional recovery after hip
fracture. J Am Geriatr Soc 2000; 48:618–24.
46 Edelstein DM, Aharanoff GB, Karp A et al. Effect of postoperative
delirium on outcome after hip fracture. Clin Orthop Relat Res 2004;
422:195–200. doi:10.1097/01.blo.0000128649.59959.0c
47 Harari D, Hopper A, Dhesi J et al. Proactive care of older people
undergoing surgery (‘POPS’): designing, embedding, evaluating and
funding a comprehensive geriatric assessment service for older
elective surgical patients. Age Ageing 2007; 36:190–6. doi:10.1093/
ageing/afl163
48 Katz RI, Barnhart JM, Ho G et al. A survey on the intended
purposes and perceived utility of preoperative cardiology
consultations. Anesth Analg 1998; 87:830–6. doi:10.1097/00000539-
199810000-00016
49 Katz RI, Cimino L, Vitkun SA. Preoperative medical consultations:
impact on perioperative management and surgical outcome. Can J
Anaesth 2005; 52:697–702. doi:10.1007/BF03016556