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Can probiotics be an alternative to chlorhexidine for oral care in the mechanically ventilated patient? A multicentre, prospective, randomised controlled open trial. Critical Care (2018) 22:272. Introduction.
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Can probiotics be an alternative to chlorhexidine for oral care in the mechanically ventilated patient? A multicentre, prospective, randomised controlled open trial Critical Care (2018) 22:272
Introduction • Ventilator Associated Pneumonia (VAP) occurs in 5-50% mechanically ventilated patients in ICU • Increased costs and length of stay • Develops primarily due to aspiration of microorganisms in the oropharyngeal secretions or fragments of biofilm from the ETT • Clearance of secretions reduced by sedating medications
Introduction • Approaches to address VAP: • Prevention bundles • ETTs with subglottic suction • Selective Oral Decontamination (SOD) • Selective Digestive Decontamination (SSD) • All have evidence to suggest they decrease VAP incidence and improve survival
Introduction • Both SOD and SSD associated with risk of developing resistant bacteria • Chlorhexidine (CHX), antiseptic used in oral care in intubated patients in many ICU. • Demonstrated to reduce incidence of VAP • Induces bacterial resistance and hypersensitivity
Introduction • Competing stable probiotics reduce the need for antiseptics and antibiotics • Investigated whether Lactobacillus Plantarum 99 (LP299) could serve as alternative to CHX • LP299 adheres to mucosa via mannose-specific mechanism, blocking sites for possible pathogenic microorganisms • Genomically closely related LP299v is common additive in many juices and milk products • Safe • Demonstrated to work equally in the critically ill as the well • Had already completed a 50 pt single centre pilot – this is an extension
Method • Approved by local ethics • Initial part of the study (50pt 29/1/04-22/3/07) performed in ICU Skåne University, Sweden • Extended part (100 additional pt 27/5/10-26/1/15) in same facility as well as in Kristianstad and Halmstad. • Pts followed up for 6/12 from inclusion
Method • Same protocol used in both parts of study • Patients randomised via sealed envelopes to standard oral treatment or treatment with Lp299.
Method • Inclusion • 18yr or older • Critically ill with anticipated need for MV for at least 24h • Intubated and ventilated within 24h of inclusion • Exclusion • Moribund • Pneumonia as admitting diagnosis • Facial or base of skull fracture • Oral ulcers • Immunodeficient • HIV or viral hepatitis • Tracheostomy • No standard oral care
Method • Oral care performed twice a day • Dental prostheses were removed; secretions were removed by suction; teeth were brushed using toothpaste and all mucosal surfaces were cleansed with swabs moistened with a 1 mg/ml CHX solution • In the Lp group the initial mechanical steps were the same as in the control group, but the subsequent cleansing was instead performed with gauze swabs soaked in carbonated bottled water, after which Lp299 was applied to the mucosal surface of the oral cavity. • This application was done using two gauze swabs (one for each side of the oral cavity) that had been allowed to absorb 10 ml of a solution containing a total of 1010 colony-forming units (CFU) of Lp299; excess suspension was not removed
Method • Participation ended after extubation or discharge from ICU • Cultures taken from oropharynx and from trachea at inclusion. • Sampling repeated on d2/3/5/7/10/14/21 • One set of cultures analyzed routinely, another set sent blinded to research lab for identification and quantification of total CFU of lactobacilli and identification of LP299.
Method • Enteral feed started when patients stable and increased according to departmental protocol. • Stress ulcer prophylaxis (Esomeprazole) given from admission until full feed established • Study not powered to detect differences in VAP • VAP was recorded • new, persistent or progressive infiltrate on chest radiograph combined with at least three of the other four criteria; a purulent tracheal aspirate; positive culture of tracheal aspirates occurring after 48 h of mechanical ventilation; rectal or urine bladder temperature higher than 38.0 °C or less than 35.5 °C; and WBC count more than 12 or less than 3 [31], or a rapid increase in WBC count without suspicion of infection in another organ.
Method • For the main duration of the mechanical ventilation period, the patients were placed in a semi-recumbent position and ventilated in a pressure-controlled or pressure-supported mode. • A heat moisture exchange filter was used routinely, but active humidification was applied if secretions were more viscous. • Suctioning of the airways was performed with a closed suction system • Most of the patients inhaled 2.5 mg of salbutamol and 0.5 mg of ipratropium every 6 h
Statistics • A primary power calculation was made addressing the VAP issue. • Anticipating a halving from 12% of the VAP incidence for the probiotic group compared to the standard procedure group, a total number of 778 patients would have been required • Decided to make this first expansion aim- ing at a confirmation of our primary results.
Results • Total of 150 patients included: • 69 (23+46) LP and 68 (21+47) Controls completed - 138 • 13 excluded as <24h MV or consent withdrawn • 5 (LP) and 8 (control) had tracheostomy • One patient transferred to another centre
Results • Patients with oropharyngeal cultures positive for enteric bacteria (with or without positive tracheal cultures) had: • Higher APACHE II score (p = 0.049) • Longer ventilator time (p=0.015) • Longer stay in the ICU (p= 0.048) • In probiotic oral care group, Lp299 was identified in tracheal secretion samples from 31 (45%) of the patients • Enteric bacteria were also found in 15 of those subjects. • No adverse events attributable to Lp299 were registered. • VAP was identified in 7 (LP group) and 10 (control) respectively (p = 0.45)
Discussion • Similar fraction of patients with emerging potentially pathogenic bacteria in both LP299 compared with CHX control group • Previous study showed a trend towards better results for the probiotic treatment with regards to new emerging enteric bacteria • Not confirmed here
Discussion • Antiseptic CHX active against normal oral bacterial flora but only has limited effect on Gram-negative bacteria. • Recent reviews concluded that oral care with CHX reduces VAP incidence but does not influence survival rate • Other meta-analysis has shown VAP not associated with any change in mortality
Discussion • CHX reacts with lipids in the cell membrane. Leads to release of intracellular content and triggers inflammatory process • ?explains meta-analysis showing increased mortality in CHX-treated patients • Aspiration (positive identification of LP299 in LP group) suggests that nearly half of patients treated with CHX as antiseptic are at risk of harm to lungs • CHX induces allergies and/or severe anaphylaxis
Discussion • LP 299 reduces pathogenic bacteria overgrowth in gut in critically ill patients • Adheres to intestinal mucosa to same extent as in healthy volunteers • Hypothesized that LP 299 would be able to outcompete oral pathogens in mechanically ventilated patients • Found no difference in the incidence of new pathogens in the oropharynx or in tracheal samples between the two groups in our study, indicating that LP299 might have an effect comparable to CHX to counteract oropharyngeal pathogenic colonisation • LP299 not implicated to have important side effects
Discussion • The three presented alternative methods for reduction of VAP have different onsets. In our study the objective was to reduce pathogens in the oropharynx in order to minimise microbial load if aspiration occurs. • In general, probiotics have no serious side efffects and thus appear to represent a seemingly harmless and ecological principle • SOD and SDD do increase the occurrence of resistant species in the GI tract. Colistin is a component in most SDD and SOD regimens. It should be noted that the frequency of colistin-resistant bacteria is increasing.
Limitations • Study performed in 2 steps and routines may have changed • Did not include enteral administration of LP299 • Study was not powered for non-inferiority and number of patients limited
Conclusion • The clinical implication of our study is that Lp299 could be considered as an alternative for oral hygiene care in mechanically ventilated patients.
My thoughts • Small research group • Long recruitment time and very small numbers • Some funding from the LP299 manufacturer • Purpose of this study is to show non-inferiority to CHX
subglottic suction