Efficacy of Gentamicin versus Chlorhexidine as a Sole Prophylactic Oral Decontaminant in Reducing the Incidence of Ventilator Associated Pneumonia: A Randomised Clinical Study

Abstract

Introduction: Ventilator Associated Pneumonia (VAP) is the second most common nosocomial infection. Aspiration of bacteria from the upper digestive tract is important in the pathogenesis of this infection. Oral decontamination using antiseptic like chlorhexidine reduces the incidence of VAP but not mortality. There is conflicting results about oral decontamination with antibiotics in preventing VAP, some suggesting benefit and others showing no benefit. Aim: To use two different prophylactic oral decontaminant, gentamicin and chlorhexidine, to compare the incidence of VAP, prevalence of bacterial flora, duration of Intensive Care Unit (ICU) stay, and mortality. Materials and Methods: The present study was a randomised, clinical study conducted at Sir Sunder Lal Hospital, Banaras Hindu University, Varanasi, Uttar Pradesh, India from January 2017 to December 2018. Patients intubated within 24 hours of admission and who needed mechanical ventilation with an expected duration of more than 48 hours were included. All the adult patients between age group 18-50 years were included in study. Patients were randomised to receive either Topical Antimicrobial Prophylaxis (TAP) with 2% gentamicin (Group G) or to 2% chlorhexidine (Group C). Patients were followed until extubation or death. Sequential cultures from endotracheal tube were sent on days 3,7,14, and 21, and for oropharyngeal swab culture were sent on days 0, 3,7,14 and 21. VAP was diagnosed with the help of Clinical Pulmonary Infection Score (CPIS). Results: Out of 151 patients, 82 patients were placed in group G (2% gentamicin) and 69 in group C (2% chlorhexidine). On follow-up of various interval among both the groups, CPIS increased with ICU stay but incidence of VAP was comparable between the groups (50% vs 71%, p=0.009). Pseudomonas was found to be most prevalent bacteria among both the groups. Discharge rate from ICU was higher in group G (54.9%) than group C (52.2%) (p-value=0.744). The mortality rate was higher in the group C (43.9%) than group G (44.9%) (p-value=0.744). Conclusion: Prophylactic oral-decontamination with gentamicin or chlorhexidine does not reduce incidence of VAP and outcome among ICU patients. Gentamicin could be a better option for patients on ventilator because it may lead to less colonisation of Pseudomonas in oral cavity along with lower CPIS in the later stages of VAP.