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Preoperative Chlorhexidine Mouthwash Cuts SSI and Bacterial Colonisation in Elective Abdominal Surgery
In a double-blind RCT of 228 adults with poor oral hygiene undergoing elective abdominal surgery, two preoperative rinses with 0.2% chlorhexidine reduced surgical site infections more than fivefold compared to saline (4.39% vs 21.93%, p<0.001) and cut positive bacterial culture rates from 62.28% to 21.05% (p<0.001). These large effect sizes across multiple infection-related outcomes suggest a clinically meaningful benefit from a simple, low-cost intervention, though the absence of reported confidence intervals and a single-centre design warrant measured interpretation.
What Was Studied
The trial investigated whether preoperative oral decontamination with chlorhexidine mouthwash could reduce postoperative infectious complications — including sore throat, fever, pneumonia, surgical site infections, and bacterial colonisation — in patients with documented poor oral hygiene undergoing short-duration elective abdominal surgery. The question is clinically important because the oral cavity in patients with poor hygiene harbours a higher burden of pathogenic organisms capable of causing respiratory and wound infections when aspirated or disseminated during the perioperative period.
How It Was Studied
This was a double-blind, randomised controlled trial conducted at a single centre in North India. Eligible participants were adults aged 18 to 65 years, classified as ASA physical status I or II, with an Oral Hygiene Index greater than 6 — indicating poor oral hygiene — who were scheduled for elective abdominal surgery under general anaesthesia anticipated to last under four hours. A total of 228 patients were enrolled and randomised to receive either 0.2% chlorhexidine mouthwash or a normal saline mouthwash, each administered twice in the preoperative period. Microbiological cultures, C-reactive protein levels, complete blood counts, and chest X-rays were assessed at postoperative days 1, 3, and 7 to capture both early and delayed infectious outcomes.
What Was Observed
- Surgical site infections were approximately five times more common in the saline group than in the chlorhexidine group (21.93% vs 4.39%, p<0.001), representing a substantial reduction in wound-related infectious complications with the active intervention.
- Positive bacterial cultures fell from 62.28% in the saline group to 21.05% in the chlorhexidine group (p<0.001), indicating that preoperative oral decontamination meaningfully reduced detectable pathogenic colonisation in the postoperative period.
- Postoperative sore throat, a marker of airway irritation and potential microaspiration, occurred in 18.42% of the chlorhexidine group versus 47.37% in the saline group (p<0.001) — a more than twofold difference that also correlated with reduced CRP elevation, suggesting lower systemic inflammatory response.
- Length of hospital stay was significantly shorter in the chlorhexidine group (p<0.001), while pneumonia rates were low and did not differ significantly between groups, likely reflecting the short-duration, lower-risk surgical context.
Why This Matters
Postoperative respiratory and wound infections contribute meaningfully to surgical morbidity and healthcare resource use, and patients with poor oral hygiene represent a particularly vulnerable subgroup due to higher oral microbial burden. This trial provides direct evidence that a brief, inexpensive preoperative oral hygiene intervention can reduce infection-related outcomes even in shorter-duration, lower-risk abdominal procedures — a context where such interventions had not previously been evaluated. The findings are especially relevant for low-resource settings, where preventing postoperative infections through low-cost means could have a disproportionate impact on patient outcomes and healthcare costs.
How to Read This Result
While the large and statistically significant effect sizes across multiple outcomes are encouraging, this was a single-centre trial restricted to patients with poor oral hygiene in one geographic setting, and the absence of reported confidence intervals limits precise quantification of the true effect range; results should be interpreted as promising but in need of multi-centre replication before broad generalisation.
Limitations
The abstract does not explicitly report study limitations.