Postoperative pneumonia (POP) is the most common complication following elective abdominal surgery. POP affects up to 40% of patients following elective abdominal surgery or X million patients in England alone. It increases morbidity and mortality for patients and resource costs for the health service. Level 1 evidence suggests oral decontamination with 0.2% cholorhexidine (ODC) reduces the incidence of pneumonia by 20% in selected patients mechanically ventilated for long periods (days to weeks). However, approximately 95% of surgical patients are extubated immediately following elective abdominal surgery. This study will determine the (i) clinical and (ii) cost effectiveness of preoperative ODC in this setting.



Preoperative ODC mouthwash is effective in reducing incidence of POP compared to a control mouthwash in patients undergoing major elective abdominal surgery



Pragmatic, multicentre, double blinded, randomised controlled study. An embedded pilot phase in 10 hospitals rolling into a full study involving >100 secondary care hospitals



Patients undergoing elective abdominal surgery



Inclusion – Age >18 years and < 80 years; Elective surgery (admitted either the night before or on the day of surgery); Major surgery (>1 planned night postoperative stay); Open and/or laparoscopic surgery on the abdomen for oesophago-gastric, hepatobiliary / pancreatic, small bowel, colorectal, urological and vascular diseases

Exclusion – Pregnancy; Recent or active pneumonia (<15 days from initial evaluation); Therapeutic course of antibiotics within 15 days of surgery; Pre-existing tracheostomy; Documented allergy to chlorhexidine; Recent emergency or elective open and minimally invasive surgery within 90 days of surgery



Patients will be randomised in a 1:1 manner to either (i) Oral decontamination with 0.2% cholorhexidine mouthwash or (ii) a placebo comparable in colour, taste, and smell. Randomisation will occur in the anaesthetic room and the treatment administered and observed by the anaesthetist. No other variation from standard pre-, peri- or post-operative care will be required for the study



Primary –             Incidence of in-hospital POP as defined by Centers for Disease Control and Prevention criteria for nosocomial pneumonia

Secondary –       Quality of life as measured by (i) respiratory-specific and (ii) general recovery questionnaires

Post operative resource use as measured by (i) length of stay, (ii) readmission at 30 days, (iii) unplanned intensive care admission and duration, (iv) reintubation at 30 days, (v) infective complications at 30 days, (vi) antibiotic use at 30 days, (vii) Chlorhexidine related adverse events at 30 days

Follow up beyond 90-days collected in the funded trial is planned through routinely collected data linkage (GP records to Hospital Episode Statistics)


Sample size:



Expertise so far:              

  • Academic Department Surgery, University of Birmingham (UoB)

o   Trainee- and consultant-networks; resources and pathways from WMRC studies

  • Cancer Research Clinical Trials Unit, UoB

o   Pedigree in delivering national and international multicentre studies with medicinal products

  • Centre for Translational Inflammation Research, UoB

o   Pedigree in delivering national multicentre studies with a focus on respiratory clinical outcomes

  • School of Immunity and Infection, UoB

o   Focus on the intervention and respiratory outcomes

  • Health Economics Unit, UoB

o   Focus on benefits to the wider NHS

  • PPI group, University Hospital Birmingham Foundation Trust

o   Focus on benefits to the wider NHS

  • School of Health and Population Sciences, UoB

o   Expertise in outcomes research, including the use of composite and patient reported outcomes, notably quality of life

Links and downloads

Latest POP audit protocol: POP_audit_protocol_V2


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