In discussing VAP is necessary to understand that they are hospital-acquired pneumonia (HAP), and is the main cause of death from hospital infections in critically ill patients and the second most common cause of nosocomial infections (12). As an aggravating factor in the pandemic, it is known that about 33% of hospitalized patients with COVID-19 tend to require ICU care. In addition, up to 20% of these patients may require the use of invasive mechanical ventilation (13). This reaffirms the need for intraoral topical antiseptic measures for preventing infections of those under mechanical ventilation and to act against the imbalance of the intraoral biome (14,15,16).
Some studies have demonstrated the application of topical products in patients on mechanical ventilation, such as chlorhexidine and povidone-iodine (17,18,19). Chlorhexidine is the gold standard. However, the reduction in the incidence of VAP and chlorhexidine use remains controversial. There is also insufficient evidence regarding its benefits in decreasing mortality, duration of mechanical ventilation, and reduction in the length of ICU stay (18,20). Moreover, chlorhexidine has side effects that affect patients who use it for long periods, such as dental pigmentation, changes in taste, irritation, dryness, and oral mucosal lesions, teratological effects, allergy, increased bacterial accumulation after its use, pH changes, and burning sensations in the oral mucosa and on the tongue (21,22,23,24,25,26). Due to concerns relating to the side effects of chlorhexidine, particularly reports of anaphylaxis, Japan does not allow its use in the oral mucosa of patients under mechanical ventilation (19). Regarding povidone-iodine, its effectiveness in preventing VAP remains unclear due to the low number of available studies (27). Moreover, povidone-iodine use has been associated with cytotoxicity to the oral mucosal membranes and tooth pigmentation (19).
In clinical studies, 0.12% chlorhexidine antiseptic action against gram-negative bacteria such as Acinetobacter baumannii, Klebsiella pneumoniae, Pseudomonas aeruginosa, Enterobacter spp. and Escherichia coli was not effective in intubated children (17). In contrast, povidone-iodine showed a reduction in microorganisms such as streptococci, MRSA, S. pneumoniae, P. aeruginosa, P. gingivalis, and C. albicans for up to three hours (19).
As potential alternatives, a mouthwash and a toothpaste containing Pc were effective in destroying 99.99% of bacteria and fungi in vitro. There is already evidence supporting the use of Pc-containing mouthwash as a complementary therapy against COVID-19, for example, in reducing signs of the disease, reducing the length of hospital stay, as well as avoiding the need for ICU admission (8,10,11). All of these findings combined with no reports of adverse effects in clinical studies, according to the tolerability questionnaires applied support the use of Pc-containing products in patients with VAP (8,10,11).
The promising in vitro results of dental gel and mouthwash containing Pc demonstrate the need for further in vivo studies to determine whether oral care using these products can prevent VAP (27).
In this in vitro analysis, both Phtalox® Mouthwash and Phtalox® Dental Gel showed a 99.99% reduction of the tested microorganisms, demonstrating the potency of these antiseptic products. Although this study presents promising results, randomized clinical trials are needed to clarify the specific mechanism of action of these products against the microorganisms found in patients with VAP.