[Role of plasma procalcitonin in the diagnosis of ventilator-associated pneumonia: systematic review and metaanalysis]

Guidelines for Antibiotics Prescription in Critically Ill Patients

How to cite this article: Khilnani GC, Tiwari P, Mittal S, Kulkarni AP, Chaudhry D, Zirpe KG, et al. Guidelines for Antibiotics Prescription in Critically Ill Patients. Indian J Crit Care Med 2024;28(S2):S104-S216.

Diagnostic value of procalcitonin in ventilator-associated pneumonia

BACKGROUND AND OBJECTIVE

Procalcitonin (PCT) can help the early diagnosis of bacterial infections and estimate the response obtained. The objective is to study the value of PCT for the diagnosis of ventilator-associated pneumonia (VAP).

PATIENTS AND METHOD

Prospective and observational study, carried out for 18 months, in a polyvalent Intensive Care Unit (ICU). Those included were over 18 years of age, with suspected pneumonia after 48h of mechanical ventilation (MV). Collected were demographic characteristics; admission pathology; reason for beginning MV; gravity scores (APACHE II, SAPS II and SOFA); C-reactive protein (CRP) and PCT. At the time of suspicion of VAP: early or late, radiological severity, presence of septic shock, SOFA, CRP, PCT and microbiology.

RESULTS

Ninety-one patients with suspected VAP were included. The mean age was 42 (17.76) and that of hospitalisation in the ICU was 18.59 (11.69) days. VAP was confirmed in 74 patients, of which 19 (25.7%) presented septic shock. The mortality was 28.4%. There were no significant differences of the PCT in the patients who presented VAP versus those who did not present VAP (P=.449). When patients without VAP, with VAP and VAP with shock, were compared, the PCT median was 0.38 (CI95%: 0.22-1.90), 0.56 (CI95%: 0.19-1.77) and 1.93 (CI95%: 0.38-10.07), respectively (P=.169).

CONCLUSIONS

In our study, PCT did not prove useful for the diagnosis of VAP.

The current status of biomarkers for the diagnosis of nosocomial pneumonias

PURPOSE OF REVIEW

Nosocomial pneumonia is a frequent and severe nosocomial infection divided in two distinct groups: hospital-acquired pneumonia and ventilator-associated pneumonia (VAP). In this context, the VAP is notoriously difficult to diagnose clinically, resulting from the lack of a 'gold standard' method of diagnosis.

RECENT FINDINGS

The use of biomarkers may potentially improve the early diagnosis of infections allowing earlier and better identification and treatment. An exhausting list of biomarkers has been studied and although far from perfect, procalcitonin (PCT) and C-reactive protein (CRP) are the most studied biomarkers used in clinical practice. Data coming from literature suggests the use of PCT for VAP prognosis and as a based algorithm tool for the reduction of duration of pneumonia therapy, as well as, the use of the CRP dynamics to the early prediction of VAP and the response to the antibiotics.

SUMMARY

The evidence for the use of biomarkers to diagnose nosocomial pneumonia as a stand-alone tool is low to moderate. Improved performance for both PCT and CRP can be obtained by using them in association with clinical features or scoring systems but prospective studies are still needed to validate this hypothesis.

Summary of the international clinical guidelines for the management of hospital-acquired and ventilator-acquired pneumonia

A summary of the evidence and recommendations made in the ERS/ESICM/ESCMID/ALAT guidelines for the management of hospital-acquired pneumonia and ventilator-associated pneumonia http://ow.ly/S3zA30iZfLa.

Pneumonia in mechanically ventilated patients: no diagnostic and prognostic value of different quantitative tracheal aspirates thresholds

BACKGROUND

Diagnosis of pneumonia in ventilated patients is challenging due to the lack of specific and definitive clinical symptoms, laboratory data or radiological abnormalities.

METHODS

Based on quantitative tracheal aspirate (QTA) results, three groups of patients were compared: <10⁵ cfu/ml, ≥10⁵ cfu/ml and <10⁶ cfu/ml, and ≥10⁶ cfu/ml. We recorded demographic variables, underlying diseases and severity of illness at ICU admission. On the day of pneumonia diagnosis, we registered temperature, leukocyte count, C-reactive protein, Sequential Organ Failure Assessment (SOFA) score, clinical pulmonary infection score (CPIS) and adequacy of empirical antimicrobial therapy.

RESULTS

In 231 episodes, clinical presentation, laboratory data, severity of illness, CPIS, the presence of bacteremia and radiological score did not differ among the three groups. ICU and hospital mortalities were also similar in the three groups. Factors independently associated with in-hospital mortality were age, SOFA score and inappropriate antimicrobial therapy. The bacterial burden in the QTA was not included in the model.

CONCLUSIONS

Quantification of tracheal aspirate samples may not be necessary in ventilated patients clinically suspected of having nosocomial pneumonia.

A 2015 Update on Ventilator-Associated Pneumonia: New Insights on Its Prevention, Diagnosis, and Treatment

Ventilator-associated pneumonia (VAP), an infection of the lower respiratory tract which occurs in association with mechanical ventilation, is one of the most common causes of nosocomial infection in the intensive care unit (ICU). VAP causes significant morbidity and mortality in critically ill patients including increased duration of mechanical ventilation, ICU stay and hospitalization. Current knowledge for its prevention, diagnosis and management is therefore important clinically and is the basis for this review. We discuss recent changes in VAP surveillance nomenclature incorporating ventilator-associated conditions and ventilator-associated events, terms recently proposed by the Centers for Disease Control. To the extent possible, we rely predominantly on data from randomized control trials (RCTs) and meta-analyses.

A translational approach to ventilator associated pneumonia

The management of Ventilator Associated Pneumonia (VAP) presents many difficulties because of the heterogeneity of the disease; the way the immunocompromised host and the aggressive ICU environment interact is only partially discovered, the available biomarkers for diagnosis are not sufficient to ensure prompt differentiation between sick patients and patients at risk, the microbiological cultures require invasive techniques and time consuming methods. A translational medicine and bio-informatics approach can enable the identification of the main players of pathology, which may represent novel therapeutic targets or biomarker candidates. Analysis of proteome i.e. allows to individuate proteins that act as biomarkers, for patient-centered research strategies. Similarly, the genomic approach has proved useful to individuate those patients who are prone to develop VAP, and, in the future, we could be able to immunomodulate their responses to save them from nosocomial infections.