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Preoperative assessment 25
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overhydrated. Balancing fluid status with replacing
losses equally is a reasonable starting point.
Venous access should be carefully chosen since
such patients may have, or may in the future require,
arteriovenous dialysis fistulas fashioned using their
cephalic veins. In patients with chronic renal failure,
avoid using the arm with an arteriovenous dialysis fistula in situ and avoid using cephalic veins.
Operative factors
influencing preoperative
management
Nature ofthe surgery
Some operations require special preparation of
the patient, such as bowel preparation prior to
colorectal surgery or preoperative localization of
an impalpable mammographic abnormality prior
to breast surgery. Different degrees of fitness are
acceptable for different procedures. For example, a
patient with severe angina might be a candidate for
removal of a sebaceous cyst under a local anaesthetic but not for a complex incisional hernia repair
under a general anaesthetic. When the surgery will
correct the cothus, the same patient with angina would be a candidate for a general anaesthetic if it was given to
enable myocardial revascularization with aorto
coronary bypass grafts.
morbidity, different criteria apply;
National Emergency Laparotomy Audit (NELA) was
established by the Healthcare Quality Improvement
Partnership (HQIP) to describe and compare
inpatient care and outcomes of patients undergoing
emergency laparotomy (in England and Wales). It is a
national audit introduced to promote quality
improvement, by collecting highdata from all National Health Service (NHS) providers. It has significantly improved outcomes by assessing risk before surgery; guiding consent and SDM
discussions, including Treatment Escalation Plans;
and guiding the seniority of clinicians present for surgery as well as appropriate postoperative levels of
care (e.g. intensive care unit immediately after
surgery).
quality comparative
Objective operative risk
assessment
The ability to have a useful prediction of 30- day mortality and morbidity following surgery allows clinicians the opportunity to better plan patient care. Is
the risk too high, should alternative treatments be
sought and what pathway should the perioperative
period take? Most importantly, it informs the SDM
process.
Various scores exist for risk stratification, taking
type of surgery, urgency of intervention and patient
factors into account. No individual risk predictive system is totally dependable and should not be used in
isolation to direct clinical decision-
-
illustrated by the number of scoring systems
available.
making – this is
Urgency ofthe surgery
When patients present with life- threatening conditions, the risk–benefit balance often changes in favour
of surgical intervention even if there is significant risk
attached but where the alternative is probable death.
A good example is a patient presenting with a ruptured abdominal aortic aneurysm, in whom death is
often an immediate alternative to urgent surgery, and
there is little time for preoperative preparation. In
many settings, some time is available to make even
the smallest of interventions that will help in
improved outcomes, for example, nebulizers in
patients with asthma, fluid resuscitation and anticoagulation reversal.
Auditing of outcomes in emergency patients is
important to improve care and outcomes. The
Surgical risk assessment
The systems outlined below are an example of the
most used.
Two surgical models are the Physiological and
Operative Severity Score for the enUmeration of
Mortality and Morbidity (POSSUM) and the Surgical
Outcome Risk Tool (SORT).
•
POSSUM (Table 4.1) was developed as a predic-
tive scoring system for surgical mortality and
combines information regarding the patient’s
physiological status and the operative procedure.
A subsequent refinement from authors in
Portsmouth resulted in Pwidely used as an audit tool to compare estimated
mortality with actual mortality.
POSSUM, which is now
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Table4.1 Factors involved inthe estimation ofrisk using P- POSSUM
Physiological parameters Operative parameters
Age Operation severity, e.g. minor, moderate and/or major
Cardiac disease, e.g. heart failure, angina, cardiomyopathy Number of procedures
Respiratory disease, e.g. degree of exertional dyspnoea Operative blood loss
ECG, e.g. presence of arrhythmia Peritoneal soiling
Systolic blood pressure Presence of malignancy
Heart rate Urgency, e.g. elective, urgent and/or emergency
Leucocyte count
Haemoglobin concentration
Urea concentration
Sodium concentration
Potassium concentration
Glasgow Coma Score
ECG, electrocardiogram.
Table4.2 The ASA grading system
ASA grade Denition
I Normal healthy person, no co- morbidity <0.1
II Mild systemic disease that does not limit activity, e.g. current smoker, obese,
III Severe systemic disease that limits activity but is not incapacitating, e.g. poorly
IV Severe systemic disease that is a constant threat to life, e.g. recent (<3months)
V A moribund patient who is not expected to survive without surgery, e.g. a
• SORT1 was developed using data from the 2011
National Confidential Enquiry into Perioperative
Death (NCEPOD) study, ‘Knowing the Risk’. Adding
a clinical assessment component, using an experienced clinician or an MDT, has been shown to
increase its accuracy (SORT- clinical judgement
model). It has an advantage over many existing prediction tools by consisting of solely preoperative
variables and allowing rapid and easy data entry.
well- controlled hypertension or diabetes
controlled diabetes or hypertension, chronic obstructive pulmonary disease
(COPD), morbid obesity, alcohol dependence, dialysis- dependent renal failure
myocardial infarction, stroke, transient ischaemic attack (TIA), severely reduced
left ventricular function, shock, sepsis
ruptured abdominal aneurysm, massive trauma
Anaesthetic risk
assessment
The American Society of Anesthesiologists (ASA)
has produced a grading scheme to estimate comorbidity (Table4.2). Half of all elective surgery
will be in patients of grade I, that is, normal fit individuals with a minimal risk of death. As the
patient’s ASA grade increases, reflecting increased
Typical
mortality (%)
0.3
2–4
20–40
>50
co- morbidity, the postoperative morbidity and
1
http://www.sortsurgery.com
mortality increase.
Postoperative
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complications
Elizabeth Tweedle
Learning objectives
✓ To know the common postoperative complications.
✓ To be aware of measures to prevent complications.
✓ To be familiar with the assessment and management of an acutely
unwell surgical patient.
A complication of surgery can be defined as any deviation from the normal postoperative course; this definition also takes into account asymptomatic
complications. True complications should be separated from other types of negative outcome following
surgery, such as the need for a stoma in bowel surgery
or failure to achieve cure in cancer surgery.
Classification
When assessing postoperative patients on the ward, it
is essential to utilize a system to identify the most
likely complication so that the patient can be managed effectively. The most common methods of classifying complications are according to when they
occur and whether they relate directly to the operation or are remote from it.
Time ofoccurrence
• Immediate– within the first 24 hours.
• Early– within the first 30days.
•
Aetiology
• Local – involving the operation site itself.
• General– affecting any of the other systems of the
complications into a useful scheme such as the one in
Table5.1
Grading theseverity
ofcomplications
The severity of a complication can be classified in
terms of the operation (e.g. blood loss quantification
post vascular surgery) or in terms of the effect on the
patient. One such example of the latter scheme is
that classification proposed by Clavien and Dindo,
5
Late– any subsequent period, often long after the
patient has left hospital.
body, such as respiratory, urological or cardiovascular systems.
These two elements can be combined to categorize
1
Ellis and Calne’s Lecture Notes in General Surgery, Fourteenth Edition.
Edited by Christopher Watson and Justin Davies.
© 2023 John Wiley & Sons Ltd. Published 2023 by John Wiley & Sons Ltd.
Companion website: www.wiley.com/go/Watson/GeneralSurgery14
1
Pierre- Alain Clavien and Daniel Dindo, Surgeons,
University Hospital of Zurich.
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Table5.1 Postoperative complications following abdominal surgery
Time Local General
First 24 hours Reactionary haemorrhage
Second day
to 3weeks
Late Obstruction due to adhesions After extensive resections or gastrectomy
Anatomical injury, e.g. ligation
of ureter during pelvic surgery
Paralytic ileus
Infection
•
Wound
•
Peritonitis
•
Pelvic
•
Subphrenic
Secondary haemorrhage
Dehiscence
•
Wound
•
Anastomosis
Obstruction due to adhesions
Asphyxia
•
Obstructed airway
•
Inhaled vomit
Pulmonary
•
Collapse
•
Bronchopneumonia
•
Embolus
Urinary
•
Retention
•
No production (acute tubular necrosis)
Deep venous thrombosis
Enterocolitis
Bed sores
•
Anaemia
•
Vitamin deficiency
•
Steatorrhoea and/or diarrhoea
•
Dumping syndrome
•
Osteoporosis
which is now widely used. It can be summarized as
follows:
•
Grade I: Any deviation from the normal postoper-
ative course without the need for surgical, endoscopic, or radiological intervention but with
simple treatment measures such as antiemetics,
analgesia, diuretics, together with physiotherapy
and bedside attention to wounds.
Grade II: A complication requiring pharmacologi-
•
cal treatment other than allowed for grade I complications, e.g. blood transfusion or parental nutrition.
•
Grade III: A complication requiring surgical,
endoscopic or radiological intervention (a) not
requiring or (b) requiring general anaesthetic.
• Grade IV: A life- threatening complication requiring intensive care management, involving (a) single organ (e.g. renal failure) or (b) multiple organ
dysfunction.
• Grade V: Death of the patient.
Predisposing factors
Assessing a patient’s risk of complications and then
taking measures to reduce the complications is a vital
part of the surgical process. It is helpful to think about
these three areas:
• Preoperative – factors already existing before the
operation is carried out.
•
Operative– factors that come into play during the
operation itself.
Postoperative – factors introduced after the
•
patient’s return to the ward. Consider the following sections covering surgical site infection (SSI)
and thromboembolic disease as examples of this.
Surgical site infection
(SSI)
Preoperative risk factors
• Diabetes impairs neutrophil function and humoral
immunity and is a risk factor for SSI. Optimization
of glucose control should be carefully planned
preoperatively, which may necessitate referral to
the diabetes service (Chapter4).
•
Obesity (BMI > 30 kg/m
risk factor for SSI. Patients should, where
feasible, be encouraged to lose weight before
surgery, best achieved with dietetic help and
exercise.
2
) is an independent
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• Malnutrition and low BMI (<18 kg/m2) are also
risk factors for SSI.
Nasal and skin contamination with
•
Staphylococcus aureus predisposes to SSI. The
risk is reduced by using nasal mupirocin in combination with a chlorhexidine body wash before
high-
risk procedures (such as joint replacements
or paediatric surgery) and in patients who are
carriers of methicillinaureus (MRSA).
Surgical skin preparation. Patients should shower
•
but not shave prior to surgery as skin abrasions
can increase the risk of SSI. If hair removal is
required, this should be performed in theatre
using single- use electric clippers. Aqueous or
alcohol- based solutions of chlorhexidine or povidone iodine are routinely used.
resistant Staphylococcus
Operative factors
The incidence of wound infection after surgical operations is related to the type of operation and the theatre environment. The common classification of risk
groups is as follows:
1
Clean (e.g. hernia repair)– an uninfected operative
wound without inflammation and where no viscera are opened. Infection rate is 1% or less.
2
Clean contaminated – where respiratory, alimen-
tary or genitourinary tract is opened but with little
or no spillage. Infection rate is less than 10%.
3
Contaminated – where there is a major break in
sterile technique or obvious spillage or obvious
inflammatory disease, for example, a gangrenous
appendix. Infection rate is 15–20%.
Dirty or infected– where there is gross contamina-
4
tion (e.g. a gunshot wound with devitalized tissue)
or in the presence of frank pus or gross soiling (e.g.
a perforated large bowel). Infection rates of 40% or
more.
Good theatre etiquette should reduce the incidence
of nosocomial infection. This should include:
•
theatre wear, used in the theatre suite, and not
while walking elsewhere in the hospital;
• minimizing movement of staff in and out of the
operating room;
• removal of hand jewellery;
•
appropriate handwashing technique with an
aqueous antiseptic, and nail brushing, prior to
donning sterile gowns and gloves.
Operation sites and risk of SSI
Elective surgery to the liver, bile duct or pancreas
has the highest risk of SSI (9.1%), followed by large
bowel surgery (8.3%), as would be expected from the
degree of contamination in the surgical field. In contrast, hip and knee replacement surgery, where
prostheses are implanted, has the lowest risk of SSI
2
(0.5%).
Antibiotic prophylaxis
Antibiotic prophylaxis is used to prevent wound infections in certain procedures, but its use must be balanced with the risk of adverse effects. These include
the risk of Clostridium difficile–associated disease and
increased prevalence of antibiotic- resistant bacteria.
For this reason, antibiotic prophylaxis should not be
used routinely for clean uncomplicated surgery where
no prostheses are used.
The prophylactic antibiotic should cover the organisms most likely to cause infection at the particular
surgical site and be guided by the local antibiotic protocol avoiding broadble. Dosing should be repeated intraoperatively if the
duration of surgery exceeds the halfotic to maintain prophylactic cover.
Antibiotic prophylaxis is indicated as follows:
spectrum agents where possi-
life of the antibi-
Surgical indications
• Clean surgery involving the placement of a
pr
osthesis or implant, e.g. a vascular prosthesis,
prosthetic hip or heart valve
Clean- contaminated surgery such as resection in
•
prepared bowel
• Contaminated surgery and surgery on a dirty or
infected wound, where antibiotic treatment is
required in addition to prophylaxis.
Additional indications
• Valvular heart disease. In patients with valvular
heart disease, commonly rheumatic mitral valve
disease, prophylaxis is given against haematogenous bacterial colonization of the valve, resulting
in infective endocarditis.
2
Figures from the Public Health England Surveillance
of Surgical Site Infections in NHS Hospitals in England
(2019–2020).
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• Amputation of an ischaemic limb, where the risk of
gas gangrene is high, particularly with aboveamputations due to their proximity to the perineum and faecal organisms.
•
Organ transplant surgery. Prophylaxis should be
given against not only wound infection but also
opportunist viral, fungal and protozoan infections
occurring as a consequence of initial highimmunosuppression.
knee
dose
Postoperative factors
• Wound care. Wounds should be cleaned with sterile
saline for the first 48 hours. After that, non- sterile
water can be used and the patient can safely shower.
Dressings. Dressing type is important, with some
•
incorporating a transparent window so that
wounds can be inspected for SSI without removing them. Tissue glue is now commonly used and
applied over the closed incision in place of a formal dressing.
•
Open wounds. Leaving wounds open instead of
closing them is a traditional and highly effective
way of managing contaminated wounds or cavities, including the peritoneal cavity, and minimizing the risk of invasive infection.
• Negative pressure wound therapy systems. These
devices apply gentle suction to wounds, evacuating exudate and promoting healing. They can be
used two ways:
– on closed wounds (e.g. PICO™) where they have
been shown to reduce wound infection and
breakdown in high-
– on open wounds (e.g. Vacuum Assist Closure
(VAC) devices), where healing is accelerated
and granulation promoted. This may be combined with irrigation of the wound undergoing
suction.
risk patients;
Causative organisms
Analysis of hospitals in England suggests that
Gram- negative Enterobacterales (most commonly
Escherichia coli) and Staph. aureus are the most preva-
lent organisms causing SSI. Methicillin sensitive
Staph. Aureus (MSSA) is the most common organism
in joint replacement surgery, whereas Enterobacterales
are the most common cause of SSI in bowel surgery.
Polymicrobial infection, where more than one infecting bacterial species is identified, is more common
after bowel surgery, but it is also common after
coronary artery bypass grafting (CABG).
Fungal infections such as candida are generally
rare (<1%) in most surgery groups with the exception of colonic procedures with rates of 4%; they can
also be significant causes of morbidity in the
immunosuppressed.
Clinical features
Some wound infections are asymptomatic. If symptoms are present, there is often localized pain and
swelling, or the general effects of infection (malaise,
anorexia and vomiting).
Typically, there is a swinging pyrexia, and the
wound is erythematous and swollen. Pus may be seen
leaking from the wound. Removal of sutures or probing of the wound with a sterile swab releases some of
the contained pus.
Treatment
The mainstay of SSI management is drainage of the
infection. The wound is opened to release the pus,
and necrotic tissue debrided. Large wounds may
require operative debridement, but usually the
wound can be opened at the bedside. The pus
should be swabbed and the infecting organism
identified.
The infected wound is left open to heal by secondary intention, aided by a negative pressure wound
therapy device.
Systemic antibiotics are indicated in the presence
of cellulitis, with initial choice of antibiotic governed
by the likely organism, and then reviewed once bacterial sensitivities are obtained from culture of pus.
Complications
ofantibiotic therapy
Antibiotic- associated colitis:
Clostridium difcile
Broad- spectrum antibiotics disrupt the normal
commensal organisms in the gut, selecting out resistant forms, such as the toxin- producing strains
of C.difficile, a Gram- positive, spore- forming bacillus. The patient experiences severe watery diarrhoea
due to extensive colitis, and the bowel shows
mucosal inflammation with superficial whitish
yellow plaques, which may coalesce to form
pseudomembranes– pseudomembranous colitis.
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Risk factors for C. difficile colitis include antibiotics
(especially cephalosporins and quinolones), proton
pump inhibitors, as well as large bowel surgery. With
postoperative rates of approximately 1%, C. difficile
remains the most common cause of diarrhoea in hospitalized patients.
Clinical features
Mild cases present simply with watery diarrhoea.
Severe cases have a choleraonset of profuse, watery diarrhoea with excess mucus,
abdominal pain and distension, and shock due to the
profound fluid loss. Occasionally, C. difficile infection
may present with a toxic dilation of the colon.
Definitive diagnosis is made by identification of the C.
difficile toxins (A and B) in the stool. The glutamate
dehydrogenase (GDH) enzyme can also be identified
in the stool and is a sensitive test but does not discriminate between toxigenic and non(about 20% of the C. difficile population).
like picture with a sudden
toxigenic strains
Treatment
The patient is at risk of both hypovolaemia and sepsis;
ABCDE assessment (see later) is crucial with delivery
of intravenous (IV) fluid and electrolyte replacement.
Broad-
spectrum antibiotics are stopped when possible. Proton pump inhibitors should also be discontinued when possible as they allow spores to evade
gastric acid and increase transmission.
Antibiotic therapy is indicated for symptomatic
cases with a positive C. difficile toxin result. Initial
treatment is with oral metronidazole for 10 days,
while oral and/or rectal vancomycin and oral fidaxomicin are reserved for secondimmunoglobulin therapy as third line, if necessary.
Subtotal colectomy and ileostomy should be considered in medically resistant cases.
C. difficile is highly contagious, so in order to prevent further spread on the ward, scrupulous hand
hygiene should be practiced and the patient placed in
isolation until diarrhoea resolves (defined as 48 hours
of formed stool).
line therapy, with
Methicillin- resistant
Staphylococcus aureus, MRSA
Pathology
Most community- acquired species of Staph. aureus are
sensitive to flucloxacillin and methicillin (MSSA), but
increasingly in hospital, the organism is resistant to
these and other antibiotics, including cephalosporins
and gentamicin. Staph. aureus has a record of develop-
ing resistance to antibiotics. Most species already possess a β-
lactamase that confers resistance to penicillin.
MRSA strains have been increasing in incidence, and
most remain sensitive to vancomycin, although MRSA
species with reduced or no sensitivity to vancomycin
(vancomycinvancomycinrarely encountered.
intermediate Staph. aureus, VISA, and
resistant Staph. aureus, VRSA) are now
Clinical features
Most MRSA species are colonizers and do not cause
clinical infections. It can be difficult to eradicate in
individuals with open wounds (such as ulcers) or
indwelling catheters. MRSA spreads by contact, and
scrupulous hand hygiene is a cheap and effective way
to reduce colonization. Typically, the organism
causes a local infection in the same way that nonMRSA species do. It is commonly found in unwell
patients, particularly those on intensive care units
who have been on broadwho are already severely debilitated.
Aggressive targeting of MRSA in UK hospitals with a
combination of simple handwashing measures, isolation of colonized patients, and screening and eradication of MRSA in elective admissions has seen the
incidence of MRSAing the benefit of simple hygiene in controlling sepsis.
spectrum antibiotics and
related infections fall, emphasiz-
Treatment
Asymptomatic MRSA carriers in the community
rarely require decolonization. Patients for planned
admission to hospital in whom skin swabs are positive for MRSA should be managed with 5days 4%
chlorhexidine daily body wash plus mupirocin nasal
cream to attempt to decolonize.
Clinical infections are treated with intravenous
vancomycin.
Other multi- resistant organisms
ofsignicance
Extended spectrum β- lactamases
(ESBL)
While MRSA is one of the most prevalent antibioticresistant bacteria, others exist. One such class of bacteria is the Gram- negative bacteria such as Klebsiella
and E. coli that produce an ESBL, an enzyme that
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hydrolyses the β- lactam ring of β- lactam antibiotics,
including secondsporins (e.g. cefotaxime). Most ESBLteria are also exceptionally resistant to nonantibiotics such as quinolones and aminoglycosides,
the resistance for which is carried and spread to
other bacteria by plasmids. As with other resistant
organisms, they are commonly found in patients
treated with prolonged courses of broadantibiotics.
and third- generation cephalo-
producing bac-
β- lactam
spectrum
Vancomycin- resistant
Enterococci(VRE)
Enterococci constitute a significant portion of the
normal gut flora. The emergence of resistance of
enterococci to vancomycin is an inevitable consequence of the increased usage of vancomycin for
prophylaxis and treatment of MRSA, as well as the
use of similar drugs in animal foodstuffs to
enhance growth. VRE is commonly isolated in
patients who have had prolonged hospital admissions with exposure to antibiotics, such as those on
intensive care units, transplant units and haematology wards.
At present, there are a few antibiotics capable of
treating VRE, and treatment is best delayed until
microbiological sensitivities are known. As with
MRSA and ESBL, VRE are best contained by appropriate infection control measures, such as handwashing
and isolation.
Carbapenem- resistant
Enterobacteriaceae (CRE)
First identified in the USA in 2001, Enterobacter that
are resistant to carbapenem antimicrobials such as
meropenem and imipenem have spread worldwide.
Those affected have usually been subject to intensive
medical care or are immunosuppressed by drug or
disease.
While handwashing and isolation are important in
controlling the spread of resistance, CRE have been
shown to be particularly resistant to normal measures
used for cleaning sinks; therefore, ironically, these
have on occasions been themselves a source of infection if not properly disinfected.
Patients admitted from areas with a high prevalence of CRE should be isolated and swabbed until
proven not to be carriers, in order to avoid incidental
contamination.
Antimicrobial stewardship
The prevalence of bacteria with resistance to antibiotics poses an increasing healthcare challenge. In order
to limit the development of multiisms, prescribers are required to exhibit due diligence
in the use of antibiotics. This includes:
taking samples for microbiological assessment
•
before commencing treatment;
taking microbiological advice on the most appro-
•
priate antibiotic;
•
delaying initiation of therapy, where it is safe to do
so, until the organism and sensitivities are known;
•
prescribing treatment for the shortest possible
effective course;
using the most appropriate dose;
•
• where intravenous antibiotics have been prescribed,
considering stepping down to an oral formulation at
48 hours if the infection is responding.
resistant organ-
Venous thromboembolism
Deep venous thrombosis (DVT) and pulmonary
embolism (PE), a life- threatening complication of
venous thrombosis, are relatively frequent following
major surgery. Incidence rates are around 30% after
orthopaedic surgery, 8% following thoracic surgery,
7% after abdominal surgery and 4% in gynaecologic
surgery. The postoperative predisposition to thrombosis has three main components (Virchow’s triad
Increased thrombotic tendency: Following blood
1
loss and platelet consumption intraoperatively,
more platelets are produced, with numbers peaking around 10days after surgery. The new platelets
have an increased tendency to aggregate.
Fibrinogen levels also increase, predisposing to
clot formation.
2 Changes in blood flow (rheology). Increased stagna-
tion within the veins occurs as a result of immobilization on the operating table and postoperatively in
bed and with depression of respiration.
3 Damage to the vein wall prompts thrombus for-
mation on the damaged endothelium. The damage may be due to an inflammatory process in the
3
Rudolf Ludwig Carl Virchow (1821–1902), Pathologist
at the Charité Hospital, Berlin. He made many notable
discoveries, including describing Virchow’s node.
3
).
(a)
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Vein wall damage
(b)
Platelet aggregation
on damaged vein wall,
thrombus forms
(c)
Clot propagates and
occludes vein: enhanced
by turbulent or slow
blood ow, raised
brinogen and sticky
platelets; impaired by
heparin
(d)
Clot breaks off
as embolus:
a PE
Postoperative complications 33
Blood
ow
Figure5.1 (a–d) Progression of deep vein thrombosis. PE, pulmonary embolus.
Mobility factors – anticipated reduction in mobil-
pelvis or may be produced by pressure of the mattress against the calf or direct damage at operation
(particularly the pelvic veins during pelvic procedures) or by disease (e.g. pelvic sepsis).
Platelets deposit on the damaged endothelium, the
vein is occluded by thrombus, and a propagated fibrin
clot then develops, which may detach and embolize to
the lung (a pulmonary embolus, above seen; Figure5.1).
1
ity during admission
Thrombosis risk factors:
2
a Patient- related factors, such as age over 60
years, obesity, cancer treatment, previous DVT,
prothrombotic tendencies (e.g. Factor V
4
Leiden
or hormone replacement
b Admission- related factors, such as nature of
surgery (hip/knee replacements and pelvic
Risk factors
All patients admitted into a hospital setting should
have an assessment of their risk of venous thromboembolism (VTE) performed within 24 hours and
again if the clinical situation changes. For surgical
patients, this will include risks related to the type of
surgery planned. Many tools exist for the assessment
of risk of VTE, which screen for factors associated
with increased risk. The National Institute for Health
and Care Excellence (NICE) has produced a VTE risk
assessment tool, which is recommended for use in
NHS hospitals. The three components of the assessment are as follows:
surgery), sepsis and prolonged surgery
3
Bleeding risk assessment:
a Patient related: active bleeding, bleeding disor-
ders, thrombocytopaenia (platelet count
<75 × 10
acute stroke
b Admission related: surgery to the brain, spine,
or eye; use of lumbar puncture, epidural or spinal anaesthetic
4
Factor V Leiden is a G to A substitution at nucleotide 1691 of
the factor V gene rst described in the Dutch city of Leiden
in 1994; there is also a thrombophilic prothrombin mutation,
G to A at nucleotide 20210in the factor II gene (F2).
), oestrogen- containing contraceptive
9
/L), anticoagulant therapy and/or
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Synthesis of the assessment answers allows the
thrombosis and bleeding risks to be evaluated and an
appropriate recommendation made for prophylaxis.
Thromboprophylaxis
NICE guidelines exist for different therapeutic areas.
For abdominal surgery, they recommend a combination of both mechanical and pharmacological prophylaxis. Women should stop oestrogencontraceptives 4weeks before elective surgery.
Mechanical VTE prophylaxis
1
a Anti- embolism stockings (graded compression
stockings), correctly measured and worn from
admission. They should not be given to
patients with peripheral arterial disease,
peripheral artery bypass graft, peripheral neuropathy, severe leg oedema or any other condition preventing their atraumatic fit
b
Intermittent pneumatic compression (e.g.
Flotron boots)
Pharmacological VTE prophylaxis for a minimum
2
of 7 days where VTE risk outweighs the risk of
bleeding
a
Subcutaneous low molecular weight heparin
(LMWH) injections, such as dalteparin.
Fondaparinux sodium. This medication binds
b
to antithrombin III, which potentiates the neutralization Factor Xa by antithrombin.
Direct acting oral anticoagulants (DOACs),
c
such as rivaroxaban. This oral medication is a
selective direct Factor Xa inhibitor. Neither this
nor fondaparinux are commonly used for
prophylaxis in general surgery.
In addition, patients should be well hydrated and
encouraged to mobilize as early as possible after surgery. Pharmacological prophylaxis should continue
for at least 7days postregained their normal mobility. Extended prophylaxis
for 28days postoperatively is recommended for people who have had major cancer surgery in the
abdomen.
surgery or until the patient has
containing oral
Monitoring heparin therapy
inrenal failure
LMWHs are eliminated by the kidneys, and in case of
renal failure, levels of activated Factor X (Factor Xa)
rise, leading to inadvertent over- anticoagulation.
Factor Xa is responsible for cleaving prothrombin into
thrombin, and it is this factor that heparin inhibits.
Patients with renal failure should have Factor Xa levels measured regularly while on treatment and may
require dose adjustment.
Deep vein thrombosis
DVT is a major cause of morbidity and mortality
among postoperative patients. An incidence of up to
40% has been reported in general surgery patients
and may be as high as 60% among orthopaedic
patients and patients undergoing amputation for
peripheral vascular disease.
Clinical features
In over 90% of patients, occurrence of DVT is ‘silent’
and presents no symptoms. If symptoms and signs do
develop, these typically appear during the second
postoperative week, although they may appear earlier
or later.
The patient complains of pain in the calf, and on
examination, the calf is tender and warm, with swelling of the foot, often with oedema, raised skin temperature and dilation of the superficial veins of the
leg. This may be accompanied by a mild pyrexia. If the
pelvic veins or the femoral veins are affected, there is
massive swelling of the whole lower limb.
DVT of the upper limbs is increasingly common
and accounts for a small proportion of DVTs. Most of
these events are precipitated by the use of peripherally inserted central catheters (PICCs) or central
venous pressure (CVP) lines. Upper arm DVTs are
much less likely to cause pulmonary emboli than
lower limb DVTs. The detection and management
remain the same.
Special investigations
• Duplex scanning. The course of large veins can be
scanned and filling defects due to thrombi
detected. In skilled hands, duplex scanning can
detect thrombi in all the major veins at and above
the knee or elbow but is less reliable below these
levels. It has the advantage that it is simple and
non- invasive.
• Magnetic resonance imaging (MRI) scan is sensi-
tive for diagnosis of pelvic or intra- abdominal
venous thrombosis, as is contrast- enhanced computed tomography (CT).
• Venography and
sensitive tests are usually confined to research
studies.
125
I- labelled fibrinogen. These
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