American Review of Respiratory Medicine - Volumen 25, Número 2 - June 2025

Editorials

Etiological Diagnosis of Ventilator-Associated Pneumonia, The Real Challenge

Diagnóstico etiológico de la neumonía asociada al ventilador, la horma del zapato

The bacteriological diagnosis of invasive me­chanical ventilation-associated nosocomial pneu­monia (VAP) is a serious concern for physicians who treat patients sick enough to require tracheal intubation and invasive mechanical ventilation. These pneumonias occur in patients who are criti­cally ill, requiring admission to the Intensive Care Unit, endotracheal intubation, and connection to a ventilator. Under these conditions, patients are inevitably colonized by hospital-acquired microor­ganisms, usually multi-drug resistant, even more so in countries like ours compared to what is ob­served in the United States or Europe.¹ Depending on the effectiveness and integrity of defense mech­anisms, the pathogenic power, and the number of microorganisms present in the airway, patients often develop pneumonia that further worsens their condition. These pneumonias usually lead to increasing respiratory failure, disease progression, high virulence of the colonizing microorganisms, the ability of the defense mechanisms to remain intact, their sensitivity to antimicrobials, and the efficacy of the antibiotic treatment applied. Given this serious complication, it is mandatory to obtain pulmonary secretion samples before prescrib­ing broad-spectrum empirical antibiotics and to de-escalate such treatment once the diagnosis, etiology, and antimicrobial sensitivity have been confirmed.² A controversial aspect is finding a bal­ance that allows attending physicians to discover “the best fit.”

Karina Otero and Tatiana Días de Carvalho carried out a retrospective observational study, collecting data from patients with VAP treated in the Intensive Care Unit, along with the results of bacteriological studies of airway samples obtained since 2018, and including the years 2020 and 2021 (the peak of SARS-CoV-2 activity).³

The authors concluded that their findings show that, compared with the mini-bronchoalveolar lavage method, endotracheal aspiration (which consists of obtaining tracheal secretion samples through a PVC tube once the artificial airway has been bypassed) is “optimal for routine analysis, since it is more cost-effective and safer.”

It is encouraging to see colleagues treating criti­cally ill patients on invasive mechanical ventilation and conducting daily screening for the possible pres­ence of VAP. Even more so during such difficult times as those experienced since the onset of the COVID-19 pandemic in 2020, which limited the ability to man­age critically ill patients with suspected VAP.

The authors put forward a proposal regarding a debate that began more than 30 years ago and has yet to be settled, concerning the diagnostic approach to mechanically ventilated patients who are severely complicated by invasive ventilator-associated pneumonia.

In 1993, the diagnostic and therapeutic ap­proach to VAP sparked a public controversy reflected in several editorials, which were avidly followed by intensive care physicians who took sides for one position or another regarding how to manage VAP and the role of microbiological stud­ies in these patients. Chastre et al⁴ emphasized the bronchoalveolar lavage culture as a measure that would allow confirmation of the diagnosis and identification of the etiology, while Niederman et al⁴ highlighted the importance of indicating an initial broad-spectrum treatment and then, at 48 hours, once bacteriological results are available, de-escalating that treatment to minimize antibi­otic exposure. Over time, the historic controversy was resolved, and both groups went on to collabo­rate and publish together on the management of this and other types of pneumonia.

Although both bronchoalveolar lavage and the use of the protected specimen brush eventually became established as the best bacteriological methods to identify etiology and manage severe pneumonias, it also became clear that perform­ing an invasive study-one that represents only minor harm in healthy individuals, such as a bronchoscopic examination-is not as harmless in a critically ill patient. This, together with the conviction of experts who generate consensus, underscores that what is best for patients should be something readily available. Even in countries with a solid healthcare system, access to a fiberop­tic bronchoscope, protected specimen brush, and proper performance of BAL is not always guar­anteed. This has led the latest North American and European/ALAT (Latin American Thoracic Association) guidelines to recommend always car­rying out a bacteriological study before initiating treatment for VAP, but to favor less complex and costly techniques^6,7 –including tracheal aspirate with semiquantitative culture– clearly in line with what the authors of this study propose.

That said, and acknowledging my own adher­ence to the use of invasive studies (particularly BAL) in these patients, it must be taken into account that although the authors of the article in question correctly describe that the sensitivity (S) of tracheal aspirate, 75.5%, is similar to that of BAL, 75.6%, in the comparison of 22 studies,⁸ the specificity of tracheal aspirate is 61%, far lower than that of BAL, 78.9%, in 22 studies.⁹ This latter point, in the reality of today’s world, and even more so in countries like ours, with regard to antimicrobial resistance, makes it all the more urgent to be prudent when administering unneces­sary antibiotics, given their impact on worsening resistance in severe infections. The Pan American Health Organization and World Health Organiza­tion estimate that antimicrobial resistance has become a serious public health problem worldwide and affirm that by 2050 it will be the leading cause of death, with losses exceeding 100 trillion dol­lars.¹⁰ Some questions still remain: if molecular studies that confirm pneumonia, its etiology, and resistance profile within one hour were to become universally accessible, would it then be necessary to obtain the best invasive sample to reach the true pathogen and prescribe a definitive early treat­ment? That would certainly be highly desirable.

Conflict of interest

The author declares no conflict of interest related to this editorial.

REFERENCES

1. Rosenthal VD, Bijie HU, Maki DG, et al. Internation­al Nosocomial Infection Control Consortium (INICC) report data sumary of 36 countries for 2004-2009. Am J Infect Control 2012;40:396-407. https://doi.org/10.1108/00907321211254661

2. Niederman MS, Craven DE, Bonten MJ, et al. Guidelines for the Management of Adults with Hospital-acquired, Ventilator-associated, and Healthcare-associated Pneumo­nia. Am J Respir Crit Care Med 2005;171:388-416. https://doi.org/10.1164/rccm.200405-644ST

3. Otero K, Días de Carvalho K. Comparación de los mi­croorganismos encontrados en las diferentes técnicas de toma de muestra de secreciones bronquiales (mini­bal versus aspirado endotraqueal) en pacientes con re­querimiento de ventilación mecánica invasiva: estudio retrospectivo. Rev Am Med Resp 2025;25:67-76. https://doi.org/10.1108/00907321211254661

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