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Oral mucosal mouthwash with chlorhexidine does not reduce the incidence of ventilator-associated pneumonia in critically ill children: A randomised controlled trial

Published:August 07, 2021DOI:https://doi.org/10.1016/j.aucc.2021.06.011

      Abstract

      Background

      Ventilator-associated pneumonia (VAP) is one of the most frequently encountered causes of hospital-acquired infection and results in high morbidity among intubated patients. Few trials have investigated the efficacy of oral care with chlorhexidine (CHX) mouthwash for the prevention of VAP in the paediatric population.

      Objectives

      The objective of this study was to assess the efficacy of CHX mouthwash in the prevention of VAP and to determine risk factors for VAP in children aged 1 month to 18 years admitted to the paediatric intensive care unit (PICU).

      Methods

      This was a prospective, randomised, controlled, double-blind trial performed in the PICU. Patients were randomised into two groups receiving CHX (0.12%) (n = 88) or placebo (0.9% NaCl) (n = 86) and were followed up for VAP development. The main outcome measures were incidence of VAP, duration of hospital stay, duration of PICU stay, duration of ventilation, mortality, and the characteristics of organisms isolated in cases with VAP.

      Results:

      No difference was observed in the incidence of VAP and the type and distribution of organisms in the two groups (p > 0.05). In the CHX and placebo groups, we identified 21 and 22 patients with VAP, respectively. Incidence per 1000 ventilation days was 29.5 events in the CHX group and 35.1 events in the placebo group. Gram-negative bacteria were most common (71.4% in CHX vs. 54.5% in placebo). The use of 0.12% CHX did not influence hospital stay, PICU stay, ventilation, and mortality (p > 0.05). Multivariate analysis identified duration of ventilation as the only independent risk factor for VAP (p = 0.001).

      Conclusion

      The use of 0.12% CHX did not reduce VAP frequency among critically ill children. The only factor that increased VAP frequency was longer duration on ventilation. It appears that low concentration of CHX is not effective for VAP prevention, especially in the presence of multiresistant bacteria.

      ClinicalTrials.gov Identifier

      Keywords

      1. Introduction

      Ventilator-associated pneumonia (VAP), as the name suggests, is a type of nosocomial pneumonia that develops after mechanical ventilation (MV) and is a serious problem among patients in the intensive care unit (ICU).
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      Strategies to prevent ventilator-associated pneumonia in acute care hospitals.
      For the paediatric population, the Institute for Healthcare Improvement (INH) in its ‘100.000 lives’ campaign recommends oral hygiene policy to be incorporated as a component of ventilator care bundles – especially with the use of CHX for children older than 2 months.

      Improvement IFH. How-to-Guide: prevent a ventilator associated pneumonia [Available from: http://www.ihi.org/IHI/Topics/.

      Implementation of ventilator care bundle measures has demonstrated a reduction in VAP rates in adults and children.
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      • Raymakers-Janssen P.
      • Vileito A.
      • Ista E.
      Effectiveness of a ventilator care bundle to prevent ventilator-associated pneumonia at the PICU: a systematic review and meta-analysis.
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      Associations between ventilator bundle components and outcomes.
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      • et al.
      Implementation of clinical practice guidelines for ventilator-associated pneumonia: a multicenter prospective study.
      In adult studies, CHX is the most popular oral antiseptic solution, but its efficacy in preventing VAP is questionable.
      • Zhang T.T.
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      • Fu L.J.
      The effectiveness of different concentrations of chlorhexidine for prevention of ventilator-associated pneumonia: a meta-analysis.
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      Prevention of ventilator-associated pneumonia with oral antiseptics: a systematic review and meta-analysis.
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      • Miranda A.L.
      • Fachini M.M.
      • Lobo S.M.
      The use of 2% chlorhexidine gel and toothbrushing for oral hygiene of patients receiving mechanical ventilation: effects on ventilator-associated pneumonia.
      • Li J.
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      Oral topical decontamination for preventing ventilator-associated pneumonia: a systematic review and meta-analysis of randomized controlled trials.
      • Shi Z.
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      Oral hygiene care for critically ill patients to prevent ventilator-associated pneumonia.
      • Klompas M.
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      • Berenholtz S.M.
      Reappraisal of routine oral care with chlorhexidine gluconate for patients receiving mechanical ventilation: systematic review and meta-analysis.
      Paediatric research is limited on this subject, and most studies evaluate the efficacy of oral hygiene by comparing pre–post intervention periods,
      • De Neef M.
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      • Ista E.
      Effectiveness of a ventilator care bundle to prevent ventilator-associated pneumonia at the PICU: a systematic review and meta-analysis.
      while only few studies have sought to compare different oral hygiene solutions in a controlled trial (applied as a part of ventilator care bundles).
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      The incidence of ventilator-associated pneumonia (VAP) in a tertiary-care center: comparison between pre- and post-VAP prevention bundle.
      • Kusahara D.M.
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      • Pedreira M.L.
      Oral care with 0.12% chlorhexidine for the prevention of ventilator-associated pneumonia in critically ill children: randomised, controlled and double blind trial.
      • Jácomo A.D.
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      • Manso P.H.
      • Carlotti A.P.
      Effect of oral hygiene with 0.12% chlorhexidine gluconate on the incidence of nosocomial pneumonia in children undergoing cardiac surgery.
      • Sebastian M.R.
      • Lodha R.
      • Kapil A.
      • Kabra S.K.
      Oral mucosal decontamination with chlorhexidine for the prevention of ventilator-associated pneumonia in children - a randomized, controlled trial.
      A meta-analysis including critically ill children identified that care bundles were effective in reducing VAP rates; however, the study could not determine which elements of the care bundles were most effective.
      • De Neef M.
      • Bakker L.
      • Dijkstra S.
      • Raymakers-Janssen P.
      • Vileito A.
      • Ista E.
      Effectiveness of a ventilator care bundle to prevent ventilator-associated pneumonia at the PICU: a systematic review and meta-analysis.
      In children, it was determined that application of CHX gel/solution did not prevent the development of VAP in mechanically ventilated children.
      • Kusahara D.M.
      • Peterlini M.A.
      • Pedreira M.L.
      Oral care with 0.12% chlorhexidine for the prevention of ventilator-associated pneumonia in critically ill children: randomised, controlled and double blind trial.
      ,
      • Sebastian M.R.
      • Lodha R.
      • Kapil A.
      • Kabra S.K.
      Oral mucosal decontamination with chlorhexidine for the prevention of ventilator-associated pneumonia in children - a randomized, controlled trial.
      The mixed results observed in most adult trials and the lack of sufficient studies on the use of CHX for VAP prevention in children prompted the conduct of this randomised controlled trial (RCT) where the aim was to determine whether CHX mouthwash would reduce VAP incidence among children on MV. The secondary objectives of the study were to determine risk factors associated with VAP development, to identify the effects of VAP on the clinical outcome of patients, and to assess whether the oral care protocol influenced microorganisms responsible for VAP.

      2. Methods

      2.1 Study setting and population

      This was a single-centred, randomised, placebo-controlled double-blind clinical trial (Registration number; NCT04527276) conducted in our PICU between February 2019 and January 2020. We designed and conducted the trial in accordance with The Consolidated Standards of Reporting Trials (CONSORT) Statement.
      • Schulz K.F.
      • Altman D.G.
      • Moher D.
      CONSORT 2010 statement: updated guidelines for reporting parallel group randomised trials.
      The study was designed as a parallel RCT, and informed consent was obtained from each patient's legally authorised representative. The study protocol was approved by the local ethics committee (Registration number: 2018/0346).
      Consecutive paediatric patients aged 1 month to 18 years who required MV for at least 48 h were included in the study within 24 h of intubation and initiation of MV. Exclusion criteria were the following: did not consent to participate in the study, known hypersensitivity to CHX, presence of tracheotomy, undergoing MV for less than 48 h, MV for more than 24 h before PICU admission, readmission to PICU, suspected or diagnosed immunodeficiency, history of malignant disease (active or at remission), diagnosed with oral mucositis or periodontal disease, diagnosed with chronic pulmonary and/or cardiac diseases, severe oral/facial trauma, and using immunosuppressive drugs (such as corticosteroids). We included patients with preexisting pneumonia as they remain susceptible to new infections during ventilation and contribute to the burden of patients with nosocomial pneumonia.
      • Sebastian M.R.
      • Lodha R.
      • Kapil A.
      • Kabra S.K.
      Oral mucosal decontamination with chlorhexidine for the prevention of ventilator-associated pneumonia in children - a randomized, controlled trial.
      All patients were consecutively randomised (1:1) to receive either 0.12% CHX rinse solution or placebo applications using a computer-generated balanced randomisation table. Unlabelled standardised tubes containing placebo or 0.12% CHX were serially numbered and bagged for each patient with respect to randomisation. The preparation of bagged treatments and their numbering were done by personnel not involved in the study. The placebo rinse contained 0.9% NaCl (normal saline [NS]) and was identical to the 0.12% CHX rinse solution with respect to appearance, consistency, and smell. The patients, physicians, outcome assessors, and data analysts were blinded to the intervention. Randomisation and numbering of the tubes were done by personnel not involved in the study, and the allocation sequence remained concealed through the entire duration of the study.
      The standard care protocols in the PICU were as follows: semirecumbent body position to maintain head elevation ≥30°, hand hygiene, replacement of ventilator circuits with malfunction, periodic verification of intracuff pressure every 8 h to maintain a pressure of 25 cm H2O,
      • Dat V.Q.
      • Geskus R.B.
      • Wolbers M.
      • Loan H.T.
      • Yen L.M.
      • Binh N.T.
      • et al.
      Continuous versus intermittent endotracheal cuff pressure control for the prevention of ventilator-associated respiratory infections in Vietnam: study protocol for a randomised controlled trial.
      assessment of nasogastric tubes, measurment of residual gastric volume every 6 h, administration of stress ulcer prophylaxis, aseptic endotracheal tube suctioning, and sedation monitoring/evaluation.

      2.2 The oral care procedure

      Before beginning the study, nurses received a training program for VAP prevention, procedure/technique for oral hygiene, and use of oral mucosa assessment score under supervision of paediatric residents. They were trained in the method of application of solutions according to CDC guidelines to ensure uniform treatments. Nurses were blinded and were unaware of whether they were applying CHX or NS during the study. Endotracheal suctioning was performed via open suctioning using fresh suction catheters in each application. We used passive humidifiers with disposable ventilator circuits. Selective decontamination of the digestive tract and continuous aspiration of subglottal contents were not performed in any of the patients.
      Both groups (0.12% CHX and placebo) received treatments at 4-h intervals; nurses used the whole content of the 5-ml tubes. The rationale for using lower concentration of CHX was to reduce the possibility of side effects, such as mucosal erosion, while maintaining a comparable therapeutic effect.
      • Rath S.K.
      • Singh M.
      Comparative clinical and microbiological efficacy of mouthwashes containing 0.2% and 0.12% chlorhexidine.
      In both groups, nurses performed oral cleansing as follows: first, the endotracheal cuff pressure was tested to ensure proper pressure before oral care, and oropharyngeal secretions were aspirated to remove any accumulated secretions. Then, rinse solutions were applied to cleanse all areas of the oral cavity, including the anterior and posterior pharynx, gums, teeth, tongue, and buccal mucosa, with standard disposable applicator (foam swab), followed by removal of excess solution from the mouth by a sterile catheter. Strict hand hygiene was ensured during the procedures. The period of application was from the day of intubation until extubation. Presence of any adverse effect of the solutions was recorded. The Beck Oral Assessment Scale (BOAS) was used twice daily to evaluate the oral health of both groups. The BOAS has five subdimensions and examines the lips, gums, oral mucosa, tongue, teeth, and saliva. The total score from this tool ranges from 5 to 20; a lower score indicates better oral health and need for fewer interventions, while a higher score indicates need for more frequent intervention.
      • Ames N.J.
      • Sulima P.
      • Yates J.M.
      • Mccullagh L.
      • Gollins S.L.
      • Soeken K.
      • et al.
      Effects of systematic oral care in critically ill patients: a multicenter study.
      The validity of the BOAS score in the PICU setting has not been demonstrated, and research is needed to test the efficacy and efficiency of this instrument in practice; nonetheless, we used the BOAS to be able to standardise oral assessment and guide nurses in providing oral interventions.
      • Ames N.J.
      • Sulima P.
      • Yates J.M.
      • Mccullagh L.
      • Gollins S.L.
      • Soeken K.
      • et al.
      Effects of systematic oral care in critically ill patients: a multicenter study.
      Beside education of nursing staff before study initiation, the research group periodically observed PICU staff to confirm protocol adherence. The BOAS forms were completed by PICU nurses and monitored by residents, adding another level to ensure adherence to intervention and study design.

      2.3 Definitions

      For the diagnosis of VAP, the patient was required to have received at least 48 h of MV and to develop new and persistent radiographic evidence of focal infiltrates at 48 h or later, after the initiation of MV.
      • Garner J.S.
      • Jarvis W.R.
      • Emori T.G.
      • Horan T.C.
      • Hughes J.M.
      CDC definitions for nosocomial infections, 1988.
      Early-onset VAP was considered when pneumonia was diagnosed during the first 4 days of MV, and late-onset VAP was defined when pneumonia was diagnosed after 4 days of MV.
      • Wall R.J.
      • Ely E.W.
      • Talbot T.R.
      • Weinger M.B.
      • Williams M.V.
      • Reischel J.
      • et al.
      Evidence-based algorithms for diagnosing and treating ventilator-associated pneumonia.
      The diagnosis of VAP was made according to the CDC criteria in patients with no evidence of preexisting pneumonia.
      • Foglia E.
      • Meier M.D.
      • Elward A.
      Ventilator-associated pneumonia in neonatal and pediatric intensive care unit patients.
      Diagnosis of pneumonia at admission was based on clinical and radiological features. In patients with underlying pneumonia, worsening of the clinical and radiological findings according to the CDC criteria was used to suspect VAP.
      • Sebastian M.R.
      • Lodha R.
      • Kapil A.
      • Kabra S.K.
      Oral mucosal decontamination with chlorhexidine for the prevention of ventilator-associated pneumonia in children - a randomized, controlled trial.
      Briefly, the chest radiographs of patients must have shown at least one of the following abnormalities: new or progressive and persistent infiltrate, consolidation, cavitation, and/or pneumatoceles (in infants ≤1 year of age). In addition to abnormal chest radiographs, the patient should exhibit fever (38° C) with no other recognised cause or leukopenia (<4000 white blood cells/mm3) or leucocytosis (≥12,000 WBC/mm3), with the presence of at least two of the following criteria: new onset of purulent sputum, change in the properties of sputum, increased respiratory secretion or increased suctioning requirements, new onset or worsening cough, dyspnoea or tachypnoea, rales or bronchial breath sounds, worsening gas exchange (oxygen desaturations [e.g., PaO2/FiO2 levels of ≤240], increased oxygen requirements, or increased ventilation demand). The aforementioned criteria can be used to diagnose VAP in children; however, specific diagnostic criteria for VAP have been developed for infants ≤1 year of age and children >1 and ≤ 12 years of age.
      • Langley J.M.
      • Bradley J.S.
      Defining pneumonia in critically ill infants and children.
      All VAP diagnoses were confirmed by clinical microbiologists who were blinded to the study. They received the patient's deidentified clinical information and microbiological analysis results only and verified diagnosis based on objective VAP criteria.
      The frequency of VAP was defined as the number of events per 1000 ventilator days. VAP incidence was calculated as follows: (The number of cases with VAP/overall number of days with ventilator) x 1000 = VAP per 1000 ventilator days.
      • Aa K.
      • Dm E.-L.
      • F W.

      2.4 Microbiological analysis

      Microbiological analyses of endotracheal aspirate samples were performed in all patients participating in the study. They were collected on the 1st and 3rd days of MV, on suspicion of VAP, in any clinical indication, and before changing antibiotic therapy or at the initiation of antibiotic therapy. As VAP was defined as pneumonia occurring >48 h after intubation and MV, this was the time frame after which a change in the clinical and radiological findings was used to suspect VAP, and the presence of a different microbial growth on tracheal aspirate cultures was used to confirm the diagnosis. Samples were processed according to standard microbiological procedures and analysed semiquantitatively. The presence of >10,000 colony-forming units (CFUs) per mL were deemed significant.
      • Garner J.S.
      • Jarvis W.R.
      • Emori T.G.
      • Horan T.C.
      • Hughes J.M.
      CDC definitions for nosocomial infections, 1988.
      Microbial cultures of tracheal aspirates were performed routinely by the hospital's laboratory attendant who had no knowledge of the study design and patients’ treatments.

      2.5 Primary and secondary outcome measures

      Demographic data, body mass index, and clinical information, including primary diagnosis at admission, presence of pneumonia at admission, presence of other infections at admission, antibiotic/antifungal use, and enteral feeding (with time of initiation; corresponding to the start of enteral nutrition after MV sustained for at least 24 h) were recorded. Severity of illness was assessed by using the Pediatric Risk of Mortality III (PRISM III) score, and the % predictive death rate (% PDR) was also calculated within 24 h of PICU admission.
      • Pollack M.M.
      • Patel K.M.
      • Ruttimann U.E.
      PRISM III: an updated pediatric risk of mortality score.
      Antibiotic/antifungal use was defined in the presence of an episode of clinical or suspected infection requiring treatment administration.
      The primary outcome measure was incidence of VAP along with its characteristics (early- or late-onset VAP and day of VAP diagnosis) in each group. Secondary outcome measures were risk factors for VAP development, the type of organism cultured on the endotracheal aspirate, duration of PICU stay, duration of hospital stay, duration of MV, and PICU survival rate.
      The patients were followed up for a period of 14 days starting from the initiation of intubation (enrolment), during which VAP development was assessed. Patients who were extubated earlier than 14 days were followed up for 48 h after extubation.
      • Sebastian M.R.
      • Lodha R.
      • Kapil A.
      • Kabra S.K.
      Oral mucosal decontamination with chlorhexidine for the prevention of ventilator-associated pneumonia in children - a randomized, controlled trial.

      2.6 Sample size calculation

      Based on the estimated frequency of VAP in our PICU (35%) and an expected 50% reduction in the frequency of VAP, the sample size was calculated as 132 with 85% power and 5% α error. Sample size was calculated using the G∗Power, version 3.1.6, software (Heinrich-Heine-Universität Düsseldorf).

      2.7 Statistical analysis

      The SPSS Statistics for Windows, version 17.0 (Chicago, SPSS Inc.) software for the Windows operating system was used to perform statistical analysis. Baseline demographic and clinical characteristics were compared, and the primary and secondary outcomes were analysed with regard to the two treatment groups. Baseline characteristics were compared by the intention-to-treat (ITT) analysis. Descriptive statistics were used to summarise the characteristics of the studied population. Categorical variables are given as number (count) and percentages, and continuous variables are given as median and interquartile range (IQR) (25%–75%). As continuous variables of the independent groups were not distributed normally, the Mann–Whitney U test was used for comparisons. Chi-square tests were used to compare the proportions of categorical variables between groups. Independent risk factors that could influence the incidence of VAP were determined by using multivariate logistic regression analysis – backward conditional method. Independent variables were selected from variables that showed p < 0.10 significance level in univariate analysis. Before the analysis, we have selected only one factor from the variables which show correlation coefficient higher than 0.70. Between-groups comparisons of the survival times were performed with the log-rank test. Kaplan–Meier analyses (log-rank tests) were used to calculate hazard ratio (HR) for microorganisms identified in tracheal aspirate samples. Any p-value <0.05 was considered to demonstrate statistical significance.

      3. Results

      Of the 276 patients admitted to the PICU during the study period, 232 were eligible for enrolment. The exclusion of 58 patients was performed according to aforementioned criteria, illustrated in Fig. 1. Of the 174 patients enrolled and randomised, 86 received NS and 88 CHX. After completion of the study, there was a total of 70 patients in the CHX group and 68 patients in the placebo group for VAP measurements (Fig. 1). Eighteen patients in each group were excluded from the protocol owing to being intubated for duration shorter than 48 h or having died before 48 h of MV; all of these patients were included in the ITT analysis. No patients were withdrawn from the protocol owing to adverse effects of MV.
      Fig. 1
      Fig. 1Flowchart of participants. PICU: paediatric intensive care unit; ITT: intention-to-treat.
      Baseline data of the patients that were randomised for inclusion (ITT analysis), including demographic clinical variables, and BOAS scores were found to be comparable in the CHX and placebo groups (Table 1). VAP was diagnosed in 43 patients, 21 of whom were in the CHX group (30%) and 22 in the placebo group (32.4%). The VAP incidence rate was found to be 29.5/1000 ventilator days for the CHX group and 35.1/1000 ventilator days for the placebo group. Comparison showed that the groups were similar in this regard (p = 0.63) (Table 2). The median day of VAP diagnosis in the CHX group was 5 (IQR: 3.5–7.5) days as compared with 5.5 (IQR: 3–10) days in the placebo group. Onset time for VAP (early or late) did not differ between the study groups (p = 0.765) (Table 2).
      Table 1Baseline demographics and clinical characteristics by intention-to-treat analysis.
      VariablesChlorhexidine (n = 88)Placebo (n = 86)p
      Age (mo), median (IQR)52 (11–149)38 (8–67)0.083
      Age range, n (%)
       1 mo to 12 y23 (26.1)26 (30.2)0.063
       1 y to 2 y13 (14.8)14 (16.3)
       2 y to 5 y10 (11.4)20 (23.3)
       > 5 y42 (47.7)26 (30.2)
      Sex (male), n (%)52 (59.1)60 (69.8)0.141
      Body mass index17.3 (15.2–19.6)16.6 (16–18.2)0.866
      Diagnosis at admission, n (%)
       Lung disease29 (33.0)36 (41.9)0.224
       Multiple trauma18 (20.5)11 (12.8)0.175
       Neurological disease13 (14.8)13 (15.1)0.949
       Sepsis & shock10 (11.4)10 (11.7)0.956
       Renal disease2 (2.3)2 (2.3)0.981
       Metabolic disease2 (2.3)3 (3.5)0.631
       Cardiac disease2 (2.3)1 (1.2)0.574
       Malignancy2 (2.3)0 (0.0)NA
       Gastrointestinal disease1 (1.1)2 (2.3)0.547
       Others9 (10.0)8 (9.2)0.837
      PRISM III score, median (IQR)18 (14–24)18 (15–22)0.934
      %PDR, median (IQR)22 (14.5–49.3)25.8 (15.7–44.3)0.990
      Enteral nutrition n (%)69 (78.4)60 (69.8)0.193
      Time to start enteral nutrition (d), median (IQR)3 (3–4)3 (2.5–4)0.111
      Infection at admission, n (%)24 (27.3)28 (32.6)0.446
      Clinical pneumonia at admission, n (%)35 (39.8)41 (47.7)0.293
      Some patients needed more than one antibiotic at the same time.
      Antibiotic/antifungal used at admission n, (%)
       Ceftriaxone52 (59.1)50 (58.1)0.899
       Vancomycin29 (33.0)26 (30.2)0.699
       Piperacillin/tazobactam3 (3.4)5 (5.8)0.449
       Meropenem15 (17.0)15 (17.4)0.945
       Caspofungin2 (2.3)4 (4.7)0.390
       Cefotaxime13 (14.8)16 (18.6)0.498
       Others21 (23.9)20 (23.3)0.925
       BOAS (IQR)9 (8–10)8 (7–9)0.117
      PRISM: Pediatric Risk of Mortality; PDR: predictive death rate; BOAS: Beck Oral Assessment Scale; NA: nonapplicable; IQR: interquartile range.
      a Some patients needed more than one antibiotic at the same time.
      Table 2Primary outcome: incidence and characteristics of VAP.
      Primary outcome measuresChlorhexidine group (n = 70)Placebo group (n = 68)Risk ratiop
      In total numbers and percentages out of the total number of patients with VAP in each group.
      VAP (n, %)
      21 (30.0)22 (32.4)0.89 (0.43–1.84)0.765
       Early-onset VAP (n, %)8 (38.1)10 (45.5)0.73 (0.21–2.49)0.625
       Late-onset VAP (n, %)13 (61.9)12 (54.5)1.35 (0.40–4.57)0.625
      1000 ventilator days (actual number of VAP episodes).
      Incidence of VAP
      29.5 (21)35.1 (22)0.86 (0.47–1.57)0.637
      Day of VAP diagnosis (d), median, (IQR)5 (3.5–7.5)5.5 (3–10)NA0.922
      VAP: ventilator-associated pneumonia; IQR: interquartile range.
      NA: nonapplicable (sample size of one subgroup too small for comparison).
      a In total numbers and percentages out of the total number of patients with VAP in each group.
      b 1000 ventilator days (actual number of VAP episodes).
      The distribution of organisms causing VAP is detailed in Table 3. There were no significant differences in terms of the rate and the type of organisms (p > 0.05). According to comparisons of groups with log-rank test, compared with placebo, the CHX group had a daily hazard ratio of 1.374 (95% confidence interval [CI]: 0.63–2.9; p = 0.424) for gram-negative organisms and 0.41 (95% CI: 0.08–2.10; p = 0.290) for gram-positive organisms, and the difference was nonsignificant (Fig. 2). Furthermore, no significant differences were observed in other secondary outcomes, including duration of PICU stay, duration of hospital stay, duration of ventilation, and PICU survival rate (Table 3).
      Table 3Secondary outcome data of the patients from both CHX and placebo groups.
      VariableChlorhexidine group (n = 70)Placebo group (n = 68)Risk ratiop
      Gram-negative bacteria
      In total numbers and percentages out of the total number of patients with VAP in each group.
      , n (%)
      15 (71.4)12 (54.5)NA0.252
      Klebsiella pneumoniae4 (19.0)4 (18.3)1.05 (0.22–4.92)0.999
      Pseudomonas aeruginosa0 (0.0)2 (9.2)NA0.488
      Acinetobacter baumannii3 (14.3)1 (4.5)3.50 (0.33–36.66)0.345
      Stenotrophomonas maltophilia3 (14.3)1 (4.5)3.50 (0.33–36.66)0.345
      Enterobacter cloacae2 (9.4)1 (4.5)2,21 (0.18–26.38)0.607
       Haemophilus influenza1 (4.8)1 (4.5)1.05 (0.06–17.94)0.999
      Moraxella catarrhalis1 (4.8)1 (4.5)1.05 (0.06–17.94)0.999
      Escherichia coli1 (4.8)0 (0.0)NA0.488
       Elizabethkingia meningoseptica0 (0.0)1 (4.5)NA0.999
      Gram-positive bacteria
      In total numbers and percentages out of the total number of patients with VAP in each group.
      , n (%)
      3 (14.3)6 (27.3)NA0.457
      Staphylococcus aureus2 (9.5)4 (18.2)0.47 (0.07–2.91)0.664
      Streptococcus pneumoniae0 (0.0)2 (9.1)NA0.488
      Corynebacterium striatum1 (4.8)0 (0.0)NA0.488
      Gram-negative and gram-positive bacteria
      In total numbers and percentages out of the total number of patients with VAP in each group.
      0 (0.0)0 (0.0)NANA
      Others
      In total numbers and percentages out of the total number of patients with VAP in each group.
      , n (%)
      3 (14.3)4 (18.2)NA0.999
       Candida species3 (14.3)4 (18.2)0.75 (0.14–3.84)0.999
      ∗Duration of PICU stay (d), median (IQR)12 (7–21)10 (5–17)NA0.309
      ∗Duration of hospital stay (d), median (IQR)19 (12–28)17 (12–28)NA0.987
      ∗Duration of ventilation (d), median (IQR)6 (3–11)5 (3–10)NA0.517
      ∗PICU survival, n (%)72 (81.8)77 (89.5)1.90 (0.79–4.57)0.147
      VAP: Ventilator-associated pneumonia; PICU: paediatric intensive care unit; IQR: interquartile range; CHX, chlorhexidine.
      NA: nonapplicable (sample size of one subgroup too small for comparison).
      ∗Intention-to-treat analysis.
      a In total numbers and percentages out of the total number of patients with VAP in each group.
      Fig. 2
      Fig. 2Hazard ratio (HR) for ventilatory associated pneumonia with gram-negative (A) and gram-positive microorganisms (B). As compared with NS, the CHX group had similar daily hazard ratio in terms of risk of development of VAP caused by both types of organisms (log-rank test p = 0.424 and log-rank test p = 0.290). CHX: chlorhexidine, NS: normal saline, HR: hazard ratio, CI: confidence interval.
      Determination of risk factors for VAP development was performed by univariate regression analysis (Table 4). Being aged younger than 12 months (odds ratio [OR]: 2.10, 95% CI: 1.140–3.381; p = 0.017), late initiation of enteral nutrition (OR: 1.25, 95% CI: 1.068–1.481; p = 0.006), longer duration of PICU stay (OR: 1.02, 95% CI: 1.01–1.03; p < 0.001), longer duration of hospital stay (OR: 1.02, 95% CI: 1.00–1.03; p < 0.001), and longer duration of ventilation (OR: 1.03, 95% CI: 1.01–1.05; p < 0.01) were determined to be associated with increased risk of VAP development. The mortality rate was 7% in patients who developed VAP, while the mortality rate was 12.6% in patients without VAP (OR: 0.55, 95% CI: 0,17–1,78). p = 0.322). No association was found between VAP and PICU mortality (data not shown).
      Table 4Determination of risk factors on VAP development by univariate regression analysis.
      VariableVAP positiveVAP negativeOR95% CIP
      (n = 43)(n = 95)
      Chlorhexidine group, n (%)21 (48.8)49 (51.6)0.9190.506–1.6720.783
      Normal saline group, n (%)22 (51.2)46 (48.4)
      Age (mo), median (IQR)38 (5–110)46 (15–125)0.9980.994–1.0030.483
      Age range, n (%)
       1 mo to 1 y17 (39.5)20 (21.1)2.1031.140–3.8810.017
       1 y to 2 y4 (9.3)18 (18.9)0.4850.173–1.3580.168
       2 y–5 y6 (14.0)17 (17.9)0.8470.358–2.0080.707
       >60 y16 (37.2)40 (42.1)0.7940.428–1.4740.465
      Sex (male), n (%)27 (62.8)64 (67.4)0.8650.466–1.6060.647
      Diagnosis at admission, n (%)
       Lung disease19 (44.2)31 (32.6)1.4730.807–2.6900.207
       Multiple trauma7 (16.3)19 (20.0)0.8220.366–1.8470.822
       Neurologic disease5 (11.6)15 (15.8)1.4350.565–3.6470.448
       Sepsis & shock5 (11.6)10 (10.5)1.0770.424–2.7360.876
       Metabolic disease2 (4.7)2 (2.1)0.4000.097–1.6540.206
       Cardiac disease0 (0.0)2 (2.1)20.610.001-0.567
      Coefficients not converge (sample size of one subgroup too small for comparison). Boldface values represent statistical significance.
       Malignancy0 (0.0)1 (1.1)0.0490.000-0.686
      Coefficients not converge (sample size of one subgroup too small for comparison). Boldface values represent statistical significance.
       Renal disease2 (4.7)2 (2.1)2.0630.498–8.5380.318
       Gastrointestinal disease0 (0.0)3 (3.2)0.0480.000-0.482
      Coefficients not converge (sample size of one subgroup too small for comparison). Boldface values represent statistical significance.
       Others3 (7.0)8 (8.4)0.8460.262–2.7370.781
      PRISM III score, median (IQR)18 (14–22)17 (14–22)1.0080.973–1.0440.653
      % PDR, median (IQR)25.8 (13.2–44.3)22 (13.2–44.3)1.0040.993–1.0160.461
      Time to start enteral nutrition, median3 (3–4)3 (0–4)1.2571.068–1.4810.006
      (IQR)
      Infection at admission, n (%)18 (41.9)27 (28.4)1.6190.883–2.9690.119
      Clinical pneumonia at admission, n (%)21 (48.8)35 (36.8)1.4550.800–2.6460,219
      Duration of PICU stay (d), median (IQR)21 (14.5–34.5)10 (7–17)1.0211.010–1.032<0.001
      Duration of hospital stay (d), median (IQR)28 (21,5–36,25)17 (12–28,25)1.0211.009–1.032<0.001
      Duration of ventilation (d), median (IQR)13 (7–17)5 (3–9)1.0371.017–1.057<0.001
      VAP: ventilator-associated pneumonia; PRISM: Pediatric Risk of Mortality; PDR: predictive death rate; PICU: paediatric intensive care unit; OR: odds ratio; CI: confidence interval; IQR: interquartile range.
      a Coefficients not converge (sample size of one subgroup too small for comparison). Boldface values represent statistical significance.
      Results of multivariate regression analysis are presented in Table 5. The duration of ventilation was found to be the only independent risk factor associated with VAP development, with an OR of 0.89 (95% CI: 0.84–0.95; p = 0.001).
      Table 5Multivariate analysis of factors affecting VAP development (backward conditional method – step 3).
      Variable95.0% CI for Exp (B)
      ORLowerUpperP
      Duration of ventilation (d)0.890.840.950.001
      Constant6.660.001
      OR: odds ratio; CI: confidence interval.
      Other variables included in the model, chlorhexidine group (p = 0.557), and time to start enteral nutrition (p = 0.484) were found to be nonsignificant.

      4. Discussion

      This study primarily evaluated the efficacy of oral care with 0.12% CHX solution in reducing the incidence of VAP. We demonstrated no significant difference in VAP development and secondary outcomes (organisms identified in tracheal aspirate culture, PICU stay, hospital stay, duration of ventilation, and PICU mortality) between the two groups, indicating that CHX had no superiority compared with NS in reducing VAP incidence.
      There are no universally accepted guidelines on the methods of optimal oral care in the PICU, and thus, there is little evidence to support the use of various measures in the prevention of VAP, especially for the paediatric population. Different concentrations of CHX have been used for the prevention of VAP in adults. Studies utilising CHX concentrations of 0.2% failed to demonstrate significant reduction in VAP rates,
      • Fourrier F.
      • Dubois D.
      • Pronnier P.
      • Herbecq P.
      • Leroy O.
      • Desmettre T.
      • et al.
      Effect of gingival and dental plaque antiseptic decontamination on nosocomial infections acquired in the intensive care unit: a double-blind placebo-controlled multicenter study.
      ,
      • Panchabhai T.S.
      • Dangayach N.S.
      • Krishnan A.
      • Kothari V.M.
      • Karnad D.R.
      Oropharyngeal cleansing with 0.2% chlorhexidine for prevention of nosocomial pneumonia in critically ill patients: an open-label randomized trial with 0.01% potassium permanganate as control.
      whereas studies using higher concentrations (2%) reported some degree of reduction.
      • Labeau S.O.
      • Van De Vyver K.
      • Brusselaers N.
      • Vogelaers D.
      • Blot S.I.
      Prevention of ventilator-associated pneumonia with oral antiseptics: a systematic review and meta-analysis.
      ,
      • Li J.
      • Xie D.
      • Li A.
      • Yue J.
      Oral topical decontamination for preventing ventilator-associated pneumonia: a systematic review and meta-analysis of randomized controlled trials.
      However, even in the latter group of studies, no decreases were reported in the duration of MV, hospital stay, ICU stay, and mortality.
      • Li J.
      • Xie D.
      • Li A.
      • Yue J.
      Oral topical decontamination for preventing ventilator-associated pneumonia: a systematic review and meta-analysis of randomized controlled trials.
      The conflicts in the literature must also be noted. For instance, while there are studies demonstrating that CHX effectively prevents VAP at lower concentrations,
      • Johnstone L.
      • Spence D.
      • Koziol-Mcclain J.
      Oral hygiene care in the pediatric intensive care unit: practice recommendations.
      others have reported no benefit with higher concentrations in critical patients.
      • Meinberg M.C.
      • Cheade Mde F.
      • Miranda A.L.
      • Fachini M.M.
      • Lobo S.M.
      The use of 2% chlorhexidine gel and toothbrushing for oral hygiene of patients receiving mechanical ventilation: effects on ventilator-associated pneumonia.
      Owing to the absence of consensus in adult studies regarding effective CHX concentration, and also because the CDC and INH recommend 0.12% CHX for VAP prevention, we aimed to evaluate the efficacy of 0.12% CHX to ensure that adverse effects would be avoided. Also, we preferred the rinse form of CHX to enable double-blinded randomisation.
      Deviating from previous studies in adult ICUs, our study was carried out in critically ill children admitted to the PICU. The paediatric population has an important distinction from adult subjects, as their oral cavities are smaller, less accessible, and also less likely to tolerate extended manoeuvres in this area (such as cleansing of the oral mucosa by an adult). However, standard oral care given to both groups resulted in equally good oral assessment scores in our study. The BOAS value reflects the condition of the oral cavity and can be used to guide oral care in critically ill patients.
      • Ames N.J.
      • Sulima P.
      • Yates J.M.
      • Mccullagh L.
      • Gollins S.L.
      • Soeken K.
      • et al.
      Effects of systematic oral care in critically ill patients: a multicenter study.
      Research is needed to test its validity in various populations, including patients admitted to the PICU; however, assessment of the oral mucosal score before oral care is a good practical recommendation with no apparent drawback.
      • Segers P.
      • Speekenbrink R.G.
      • Ubbink D.T.
      • Van Ogtrop M.L.
      • De Mol B.A.
      Prevention of nosocomial infection in cardiac surgery by decontamination of the nasopharynx and oropharynx with chlorhexidine gluconate: a randomized controlled trial.
      Research in paediatric populations which evaluated the effectiveness of ventilator care bundles has shown significant reductions in VAP rates;
      • De Neef M.
      • Bakker L.
      • Dijkstra S.
      • Raymakers-Janssen P.
      • Vileito A.
      • Ista E.
      Effectiveness of a ventilator care bundle to prevent ventilator-associated pneumonia at the PICU: a systematic review and meta-analysis.
      ,
      • De Cristofano A.
      • Peuchot V.
      • Canepari A.
      • Franco V.
      • Perez A.
      • Eulmesekian P.
      Implementation of a ventilator-associated pneumonia prevention bundle in a single PICU.
      however, it is evident that these outcomes are associated with whole care bundle being applied and therefore cannot be directly attributed to oral care alone. There are only a few studies evaluating the efficacy of oral care with CHX in this population.
      • Osman S.
      • Al Talhi Y.M.
      • Aldabbagh M.
      • Baksh M.
      • Osman M.
      • Azzam M.
      The incidence of ventilator-associated pneumonia (VAP) in a tertiary-care center: comparison between pre- and post-VAP prevention bundle.
      • Kusahara D.M.
      • Peterlini M.A.
      • Pedreira M.L.
      Oral care with 0.12% chlorhexidine for the prevention of ventilator-associated pneumonia in critically ill children: randomised, controlled and double blind trial.
      • Jácomo A.D.
      • Carmona F.
      • Matsuno A.K.
      • Manso P.H.
      • Carlotti A.P.
      Effect of oral hygiene with 0.12% chlorhexidine gluconate on the incidence of nosocomial pneumonia in children undergoing cardiac surgery.
      • Sebastian M.R.
      • Lodha R.
      • Kapil A.
      • Kabra S.K.
      Oral mucosal decontamination with chlorhexidine for the prevention of ventilator-associated pneumonia in children - a randomized, controlled trial.
      Kusahara et al.
      • Kusahara D.M.
      • Peterlini M.A.
      • Pedreira M.L.
      Oral care with 0.12% chlorhexidine for the prevention of ventilator-associated pneumonia in critically ill children: randomised, controlled and double blind trial.
      found that the use of 0.12% CHX did not modify VAP incidence in mechanically ventilated children, demonstrating that lower CHX concentration may not be effective in the prevention of VAP. This is supported by the suggestion that CHX only has bacteriostatic action at lower concentrations, while it may be bactericidal at higher concentrations.
      • Meinberg M.C.
      • Cheade Mde F.
      • Miranda A.L.
      • Fachini M.M.
      • Lobo S.M.
      The use of 2% chlorhexidine gel and toothbrushing for oral hygiene of patients receiving mechanical ventilation: effects on ventilator-associated pneumonia.
      An RCT in which a higher concentration of CHX (1%) was applied
      • Sebastian M.R.
      • Lodha R.
      • Kapil A.
      • Kabra S.K.
      Oral mucosal decontamination with chlorhexidine for the prevention of ventilator-associated pneumonia in children - a randomized, controlled trial.
      and a paediatric cohort study in which preintervention and postintervention data after the initiation of a VAP prevention bundle (using 2% CHX) were compared both reported a lack of significant reduction in VAP rates in the PICU.
      • Osman S.
      • Al Talhi Y.M.
      • Aldabbagh M.
      • Baksh M.
      • Osman M.
      • Azzam M.
      The incidence of ventilator-associated pneumonia (VAP) in a tertiary-care center: comparison between pre- and post-VAP prevention bundle.
      Additionally, in patients undergoing cardiac surgery, oral care with 0.12% CHX was not beneficial in reducing VAP incidence.
      • Jácomo A.D.
      • Carmona F.
      • Matsuno A.K.
      • Manso P.H.
      • Carlotti A.P.
      Effect of oral hygiene with 0.12% chlorhexidine gluconate on the incidence of nosocomial pneumonia in children undergoing cardiac surgery.
      Similarly, our study did not reveal a significant difference in the incidence or timing of VAP development in the two study groups. Our result may be attributable to the critical health conditions of children in the study population. Previously established beneficial effects of CHX in adult patients may be associated with the inclusion of patients who were undergoing elective procedures, who were often in much better clinical statuses than critically ill children,
      • Labeau S.O.
      • Van De Vyver K.
      • Brusselaers N.
      • Vogelaers D.
      • Blot S.I.
      Prevention of ventilator-associated pneumonia with oral antiseptics: a systematic review and meta-analysis.
      and also with the presence of multiresistant bacteria.
      • Fourrier F.
      • Dubois D.
      • Pronnier P.
      • Herbecq P.
      • Leroy O.
      • Desmettre T.
      • et al.
      Effect of gingival and dental plaque antiseptic decontamination on nosocomial infections acquired in the intensive care unit: a double-blind placebo-controlled multicenter study.
      Also, VAP incidence was found to be relatively lower than the expected (or previously reported) values, possibly in relation with the routine utilisation of the ventilator care bundle.
      In previous paediatric studies, implementation of VAP prevention bundles did not cause a significant difference in terms of respiratory culture results,
      • Osman S.
      • Al Talhi Y.M.
      • Aldabbagh M.
      • Baksh M.
      • Osman M.
      • Azzam M.
      The incidence of ventilator-associated pneumonia (VAP) in a tertiary-care center: comparison between pre- and post-VAP prevention bundle.
      and it was observed that CHX was ineffective on the spectrum of organisms causing VAP; however, most organisms isolated were gram-negative bacteria.
      • Sebastian M.R.
      • Lodha R.
      • Kapil A.
      • Kabra S.K.
      Oral mucosal decontamination with chlorhexidine for the prevention of ventilator-associated pneumonia in children - a randomized, controlled trial.
      Grap et al. tested 0.12% CHX on VAP prevention and demonstrated that single application was effective in early-onset VAP and for pathogens such as Staphylococcus aureus and Streptococcus pneumoniae, but higher concentration was needed for gram-negative organisms.
      • Grap M.J.
      • Munro C.L.
      • Elswick Jr., R.K.
      • Sessler C.N.
      • Ward K.R.
      Duration of action of a single, early oral application of chlorhexidine on oral microbial flora in mechanically ventilated patients: a pilot study.
      This was supported by a trial evaluating 0.12% CHX in children, which concluded that the effect of CHX on VAP prevention was limited because the predominant microorganisms were not gram-positive bacteria.
      • Kusahara D.M.
      • Peterlini M.A.
      • Pedreira M.L.
      Oral care with 0.12% chlorhexidine for the prevention of ventilator-associated pneumonia in critically ill children: randomised, controlled and double blind trial.
      In the present study, although most children had multiresistant gram-negative bacteria, there was no significant difference between groups in terms of the distribution of organisms. Our study does not provide any evidence regarding efficacy of CHX in gram-negative bacteria. The outer membrane of gram-negative bacteria may act as a barrier, preventing CHX entry, and efflux proteins could facilitate resistance.
      • Cieplik F.
      • Jakubovics N.S.
      • Buchalla W.
      • Maisch T.
      • Hellwig E.
      • Al-Ahmad A.
      Resistance toward chlorhexidine in oral bacteria - is there cause for concern?.
      The use of CHX at low concentration along with the isolation of resistant bacteria and the fact that all patients had severe illness are factors that could be associated with the lack of differences in our study. We believe more studies using higher CHX concentrations are necessary to test the effects of CHX on multiresistant gram-negative organisms, especially in critically ill children.
      Regarding secondary outcomes (duration of PICU stay, hospital stay, duration of ventilation, and PICU mortality), there were no significant differences between the CHX and placebo groups, as demonstrated by ITT analysis. Our results support previous paediatric studies that reported similar outcomes.
      • Kusahara D.M.
      • Peterlini M.A.
      • Pedreira M.L.
      Oral care with 0.12% chlorhexidine for the prevention of ventilator-associated pneumonia in critically ill children: randomised, controlled and double blind trial.
      • Jácomo A.D.
      • Carmona F.
      • Matsuno A.K.
      • Manso P.H.
      • Carlotti A.P.
      Effect of oral hygiene with 0.12% chlorhexidine gluconate on the incidence of nosocomial pneumonia in children undergoing cardiac surgery.
      • Sebastian M.R.
      • Lodha R.
      • Kapil A.
      • Kabra S.K.
      Oral mucosal decontamination with chlorhexidine for the prevention of ventilator-associated pneumonia in children - a randomized, controlled trial.
      Risk factors for VAP development differ between adults and children. Unlike adults, children have developmental and physiological differences that cause important variations.
      • Bonten M.J.
      • Kollef M.H.
      • Hall J.B.
      Risk factors for ventilator-associated pneumonia: from epidemiology to patient management.
      Some of the known risk factors for the development of VAP are use of opiates for sedation, sustained neuromuscular blockade, use of enteral nutrition, previous antibiotic therapy, the technique used for endotracheal suctioning, reintubation, ventilator circuit changes, gastroesophageal reflux, subglottal or tracheal stenosis, being a young infant or being older than 10 years, and having trauma or surgical problems.
      • Bonten M.J.
      • Kollef M.H.
      • Hall J.B.
      Risk factors for ventilator-associated pneumonia: from epidemiology to patient management.
      Children admitted to the PICU have a number of distinguishing characteristics that may increase the risk of VAP. Compared with adult ICU patients, children have risks such as the use of uncuffed endotracheal tube ( ETT) or nasal ETT , open circuit suctioning, saline lavage during suctioning, and novel oral properties due to continuing dental development.
      • Segers P.
      • Speekenbrink R.G.
      • Ubbink D.T.
      • Van Ogtrop M.L.
      • De Mol B.A.
      Prevention of nosocomial infection in cardiac surgery by decontamination of the nasopharynx and oropharynx with chlorhexidine gluconate: a randomized controlled trial.
      In the present study, patients younger than 12 months were found to be 2 times more likely to develop VAP, which is a finding that is in support of prior studies.
      • Samransamruajkit R.
      • Jirapaiboonsuk S.
      • Siritantiwat S.
      • Tungsrijitdee O.
      • Deerojanawong J.
      • Sritippayawan S.
      • et al.
      Effect of frequency of ventilator circuit changes (3 vs 7 days) on the rate of ventilator-associated pneumonia in PICU.
      This result may be because infants are more vulnerable to VAP owing to the fact that age is an important factor for immunity.
      • Langley J.M.
      • Bradley J.S.
      Defining pneumonia in critically ill infants and children.
      Late initiation of enteral nutrition, longer PICU stay, longer hospital stay, and longer duration of MV were found to be risk factors for VAP development by univariate analysis. Similar results were found by Elward et al.,
      • Elward A.M.
      • Warren D.K.
      • Fraser V.J.
      Ventilator-associated pneumonia in pediatric intensive care unit patients: risk factors and outcomes.
      who reported that the duration of PICU stay, length of hospital stay, and PRISM III scores were risk factors for VAP.
      Even though it is known that the development of VAP increases mortality in ICUs,
      • Fourrier F.
      • Dubois D.
      • Pronnier P.
      • Herbecq P.
      • Leroy O.
      • Desmettre T.
      • et al.
      Effect of gingival and dental plaque antiseptic decontamination on nosocomial infections acquired in the intensive care unit: a double-blind placebo-controlled multicenter study.
      ,
      • Chastre J.
      • Fagon J.Y.
      Ventilator-associated pneumonia.
      the risk for mortality can be reduced by general infection prevention measures, prevention of cross-transmission, policy of restricted antimicrobial use, early recognition, and prompt initiation of empirical antimicrobial therapy.
      • Blot S.
      Limiting the attributable mortality of nosocomial infection and multidrug resistance in intensive care units.
      It is demonstrated that mortality can be limited when infection is adequately managed.
      • Blot S.
      Limiting the attributable mortality of nosocomial infection and multidrug resistance in intensive care units.
      In the present study, we did not find any relationship between VAP development and PICU mortality. This finding is presumably related to early diagnosis and swift use of appropriate antibiotics with respect to antibiotherapy guidelines.
      At this point, we believe it is critical to note that there are studies that suggest the use of CHX mouthwash may increase the risk of mortality in adult ICUs,
      • Parreco J.
      • Soe-Lin H.
      • Byerly S.
      • Lu N.
      • Ruiz G.
      • Yeh D.D.
      • et al.
      Multi-Center outcomes of chlorhexidine oral decontamination in intensive care units.
      while being ineffective in decreasing the likelihood of pneumonia
      • Price R.
      • Maclennan G.
      • Glen J.
      Selective digestive or oropharyngeal decontamination and topical oropharyngeal chlorhexidine for prevention of death in general intensive care: systematic review and network meta-analysis.
      – especially in the general hospitalised population.
      • Deschepper M.
      • Waegeman W.
      • Eeckloo K.
      • Vogelaers D.
      • Blot S.
      Effects of chlorhexidine gluconate oral care on hospital mortality: a hospital-wide, observational cohort study.
      Although this may appear controversial and, therefore, has led to debates on this topic, a recent study has suggested that mouthwashes could alter the nitric oxide homoeostasis of the oral region owing to eradication of the majority of oral bacterial flora, ultimately causing a nitric oxide–deficient condition.
      • Blot S.
      Antiseptic mouthwash, the nitrate-nitrite-nitric oxide pathway, and hospital mortality: a hypothesis generating review.
      A reduction in nitric oxide bioavailability may have various injurious effects and has been associated with the occurrence or worsening of high-mortality pathologies, including atherosclerosis, diabetes, and sepsis. The loss of normal physiological characteristics and natural oral flora may result in adverse effects rather than preventive effects. Thus, we believe readers should be aware of this relationship when considering the use of mouthwash (not only CHX-based solutions) in the PICU setting, especially when designing future studies on this topic.
      Analysis of independent risk factors revealed longer duration of ventilation to be the sole factor that was significant for VAP development in our group of patients. Similar results have been found in previous studies.
      • Liu B.
      • Li S.Q.
      • Zhang S.M.
      • Xu P.
      • Zhang X.
      • Zhang Y.H.
      • et al.
      Risk factors of ventilator-associated pneumonia in pediatric intensive care unit: a systematic review and meta-analysis.
      ,
      • Coffin S.E.
      • Klompas M.
      • Classen D.
      • Arias K.M.
      • Podgorny K.
      • Anderson D.J.
      • et al.
      Strategies to prevent ventilator-associated pneumonia in acute care hospitals.
      ,
      • Fourrier F.
      • Dubois D.
      • Pronnier P.
      • Herbecq P.
      • Leroy O.
      • Desmettre T.
      • et al.
      Effect of gingival and dental plaque antiseptic decontamination on nosocomial infections acquired in the intensive care unit: a double-blind placebo-controlled multicenter study.
      ,
      • Bonten M.J.
      • Kollef M.H.
      • Hall J.B.
      Risk factors for ventilator-associated pneumonia: from epidemiology to patient management.
      ,
      • Chastre J.
      • Fagon J.Y.
      Ventilator-associated pneumonia.
      There were some limitations in the present study. First, heterogeneity of the patient population can be considered as an important factor; however, this feature undoubtedly reflects the characteristics of the PICU setting. Second, it is very possible that the administration of CHX rinse significantly alters culture results with tracheal aspirate samples, owing to its direct effects on the flora of the oropharynx. Even though such effects have not been found to be at significant levels, we did not determine the effect of CHX on oropharyngeal colonisation. Additionally, the CHX concentration in aspirated samples was not assessed. Third, the placebo group received 0.9% NaCl, and this solution is known to cause dryness in the oral mucosa, especially with prolonged use; thus, the placebo application may have been effective on oral characteristics, even though it was highly unlikely to have an impact with the frequency of use during the study. Fourth, even though we strictly adhered to routine MV care, the frequency of aspiration in our patients (which may influence VAP rate) was not analysed. Intracuff pressure was checked every 8 h, but some guidelines have indeed suggested more frequent verification of cuff pressure.
      • Lizy C.
      • Swinnen W.
      • Labeau S.
      • Poelaert J.
      • Vogelaers D.
      • Vandewoude K.
      • et al.
      Cuff pressure of endotracheal tubes after changes in body position in critically ill patients treated with mechanical ventilation.
      Finally, we did not test the sensitivity of organisms to CHX. Doing so may have contributed to a better understanding of the role of CHX and its effect on oral pathogens.
      In spite of these limitations, we believe our study has several strengths. The research was carried out among intubated children in a PICU, a setting where evidence is lacking on this topic. We were able to achieve effective randomisation, blinding, and follow-up. We also used strict and objective criteria for the diagnosis of VAP. A considerable sample size capable of statistical discrimination was achieved in this single-centred study. Although the heterogeneity of the PICU population is without doubt a limitation for reliable analysis in specific patient groups, it may also be seen as a strength that enables the evaluation of the generalised role of CHX in patients on MV. Furthermore, the adherence to standard protocols provided good control of the PICU environment and patient features, which facilitates better observation of group characteristics.

      5. Conclusion

      We found that 0.12% CHX mouthwash did not prevent the development of VAP and did not affect the type of organism isolated in the tracheal aspirate samples of children on MV. Although it has been well established that ventilator care bundles are effective in preventing VAP, we conclude that use of CHX at low concentration has no benefit in terms of VAP development in critically ill children with multiresistant bacteria. To elucidate the possible role of CHX mouthwash for prevention of VAP in critically ill children, we need more evidence obtained from larger trials, preferably evaluating different concentrations and longer or more frequent interventions. With these data, we recommend implementation of ventilator care bundles as the primary measure to prevent VAP. Following routine mouth care policy with individualised oral care approach could also contribute to better overall care in the PICU. Since longer duration on MV was found to be the only risk factor for VAP development in the present study, it is of utmost important to perform careful evaluation of patients every day to determine the need for MV support and wean patients when possible.

      Funding

      This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

      CRediT authorship contribution statement

      Zeynep Karakaya: Methodology, statistical analysis, Writing – original draft, responsible for the overall content, Writing – review & editing. Muhterem Duyu: Methodology, quality assessment, contributed to the writing of the manuscript, revised the manuscript for important intellectual content, Writing – review & editing. Meryem Nihal Yersel: Data extraction, quality assessment, Writing – review & editing.

      Conflict of Interest

      The authors declare that they have no conflicts of interest.

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