Table 2.

Summary of the current knowledge about VAP prevention [162]

Intervention	Probable impact on VAP rates	Comments
Head-of-bed elevation [116]	May lower rates	Understudied, few and contradictory randomized trials
Tapered endotracheal tube cuffs and ultrathin polyurethane [102, 104]	No impact	In vivo studies document persistently high rates of subclinical aspiration despite the theoretical advantages of these designs
Automated endotracheal tube cuff pressure monitoring [106]	May lower rates	Understudied, merits further evaluation
Subglottic secretion drainage [94]	May lower rates	Extensively studied but despite lower VAP rates no impact on duration of mechanical ventilation, ICU length-of-stay, ventilator-associated events, or mortality. Unclear impact on antibiotic utilization
Oral care with chlorhexidine [99, 100, 112]	Unclear	Extensively studied. Most individual studies negative. Meta-analysis of open-label studies suggest lower VAP rates but meta-analysis of double-blind studies find no impact. May increase mortality rates. Oral care with sterile water preferred
Selective oral and digestive decontamination [93, 119]	Likely lowers VAP rates	Extensively studied. Less net antibiotic utilization and lower mortality rates in Dutch studies. No impact on mortality in units with high baseline rates of antibiotic resistance and antibiotic utilization
Probiotics [163]	Unclear	Many studies but most of limited quality, mixed results. Lower VAP rates on meta-analysis but no signal when restricting to double-blind studies
Stress ulcer prophylaxis [92, 123, 125]	May increase VAP rates	Observational studies and some meta-analyses suggest higher VAP rates but a recent large randomized trial found no impact
VAP prevention bundles [128]	Likely lower VAP rates	Extensively studied, almost exclusively in before–after and time-series analyses. May be associated with lower mortality rates. Most benefit likely from minimizing sedation and encouraging early extubation