Introduction
Caesarean Section (CS) occur in around 1 in 4 births in the UK1 and are classified as elective, or emergency, where
the procedure is undertaken to prevent risk to the mother and unborn
child. Amongst the risks associated with a CS procedure is the
development of a surgical site infection (SSI); a serious surgical
complication defined as ‘a type of healthcare-associated infection
in which a wound infection occurs after an invasive (surgical)
procedure ’. 2 The CDC 3 further
define SSI as an infection that occurs after surgery in the part of the
body where the surgery took place. Surgical site infections can
sometimes be superficial infections involving the skin only. Other
surgical site infections are more serious and can involve tissues under
the skin, organs, or implanted material. The development of an SSI
following CS can result in permanent injury to the bladder, uterus or
rectum as well as scarring, increased pain, a reduction in mobility4 and extended hospital stays.5 A
severe and potentially fatal complication of developing an SSI is
necrotising fasciitis (NF), a rare bacterial infection affecting the
soft tissue and fascia. 6
The World Health Organization [WHO] 7 recommended
C-section rates should be between 10% and 15%. However, there has been
a gradual international increase in the amount of CS being undertaken.
In the United States, CS has been highlighted as a common procedure,
increasing by 41% in a 13-year period to its current rate of about 32%8 Similarly, high rates are currently observed in the
UK (26.5%) 9; in Australia (32.3%)10; and in China (41%). 11 In other
countries both the current proportion and rate of increase are high:
Zejnullahu et al. 12 report that in Kosovo, the rate
of CS rose from 7.5% in 2000 to 27.3% in 2015 with 33.5% of
deliveries in tertiary referral care services being C-sections.
The increase in CS risks an increase in SSI, with WHO13 warning that SSIs affect up to one-third of
patients who have undergone a surgical procedure. Almost half of SSIs
reported in the European Centres for Disease Prevention and Control
surveillance system 14 were identified as superficial,
with 30% being deep, and 20% extending to organ/space. However, Wilson
et al. 15 reported that procedures associated with a
very short post-operative stay, e.g. CS, only had infections recognised
and reported following discharge from hospital. These are therefore
likely to be underestimated given that approximately 50% of SSIs become
evident after discharge. 16 Incidence rates for the
development of SSI in CS have been reported globally, as 4.6%.17 However, Jenks et al. 18reporting on a multicentre English trial, concluded that SSI was
estimated to be just under 10% and the readmission rate due to SSI
following CS was 0.6%.
SSI represents a significant financial and patient burden, with costs
estimated at over £2 billion to the UK healthcare system, with a median
cost of £7,467 per SSI CS patient compared to £3,572 for non-SSI CS
patients. 19 Annual costs exceed US$1.6 billion in
the US 20 AU$268 million in Australia,21 and £930 million in the UK. 19Increased financial expenditure are mainly attributable to increased
length of hospital stay 18 and excess cost per
operation of £3,855, with an estimated excess cost of over £7,000,000
per hospital in the UK. 22 The pain and isolation
concomitant with suffering an SSI also significantly impacts on patient
quality of life and experiences of care. 23 Umscheid
et al. 24 argue that 60% of SSIs may be preventable
and their risk minimised by applying best practice in the
perioperative period.
The international literature has identified several risk factors that
predispose an individual developing an SSI following a CS procedure in
general, including obesity and an increased BMI, increased age,
pre-eclampsia, grade of surgeon and existing comorbidities. Indeed,
obesity, age and pre-eclampsia have been linked to post-surgical
complications, possibly compounding wound healing and increasing the
risk of infection. 25, 26 Extended labour time and the
complexities surrounding an emergency CS also impact the possibility of
post-surgical infection. 27, 28 However, there are
some inconsistences; in a multicentre study of 4107 women who underwent
a CS at 14 NHS hospitals in England, Wloch et al.29 found obesity (defined as BMI>30
kg/m2), age <20 years and grade of surgeon
to be significantly associated with developing an SSI. Obesity was also
found to increase the risk of SSI within 30 days after CS in a case
control study of 240 women at a hospital in Ireland.30 However, Najm and Majeed 31failed to find evidence to suggest that obesity was a contributing
factor in SSI development in a sample of 200 women in a hospital in
Iraq. Poor infection control monitoring and procedures may have limited
the extent to which these findings are generalisable to the wider
population.
Although there appears to be several patient level factors that make
developing an SSI following a CS more likely, the extent to which the
interaction between these elements increase the likelihood of infection,
and the distinction between the predisposing factors associated with an
elective versus emergency CS is less obvious. This is problematic, as a
lack of evidence-based guidelines contributes to inconsistencies in SSI
prevention, treatment and management in CS, increasing the economic
burden 22 and obvious detrimental effect on patient
outcomes and experiences of care. Whilst evidence-based guidelines
emphasise the prevention and treatment of SSI 1 there
is an obvious lack of guidance for the management of SSI in emergency
CS. The study objective was to quantify the incidence of Surgical Site
Infection (SSI) in patients who have had an emergency Caesarean Section
(CS), identifying the risk and associated factors that contribute to the
development of SSI in order to develop a better understanding of the
potential mechanisms that may increase the likelihood of infection and
the distinction between the predisposing factors associated with an
elective versus emergency CS.