Hemocultivos en los servicios de urgencias, ¿hacia un nuevo enfoque?

[Predictive factors of bacteraemia in the patients seen in emergency departments due to infections]

Objetivos

Analizar los factores predictivos de bacteriemia en los pacientes atendidos en el servicio de urgencias (SU) por un episodio de infección.

Pacientes y métodos

Estudio observacional, retrospectivo, descriptivo y analítico de todos los hemocultivos extraídos en un SU en los pacientes adultos (≥ 18 años) atendidos por infección desde el 1-1-2018 hasta el 1-7-2018. Se realizó seguimiento durante 30 días. Se analizaron 38 variables independientes (epidemiológicas, de comorbilidad, funcionales, clínicas y analíticas) que pudieran predecir la existencia de bacteriemia. Se realizó un estudio univariado y multivariante mediante regresión logística.

Resultados

Se incluyeron 1.425 episodios de hemocultivos extraídos. De ellos se consideraron como bacteriemias verdaderas 179 (12,6 %) y como HC negativos 1.246 (87,4 %). Entre los negativos, 1.130 (79,3%) no tuvieron crecimiento y 116 (8,1%) se consideraron contaminados. Cinco variables se asociaron de forma significativa como predictoras de bacteriemia verdadera: procalcitonina (PCT) sérica ≥ 0,51 ng/ml [odds ratio (OR): 4,52; intervalo de confianza (IC) al 95%: 4,20-4,84; p <0,001], temperatura > 38,3°C [OR: 1,60; IC al 95%: 1,29-1,90; p <0,001], presión arterial sistólica (PAS) < 100 mmHg [OR: 3,68; IC al 95%: 2,78-4,58; p <0,001], shock séptico [OR: 2,96; IC al 95%: 1,78-4,13; p <0,001] y la existencia de neoplasia [OR: 1,73; IC al 95%: 1,27-2,20; p <0,001].

Conclusiones

. Existen varios factores disponibles tras una primera valoración en el SU, entre ellos la PCT sérica, la temperatura, la hipotensión con/sin criterios de shock séptico y la existencia de neoplasia, que predicen la existencia de bacteriemia verdadera.

Ability of procalcitonin to differentiate true bacteraemia from contaminated blood cultures in an emergency department

OBJECTIVES

To analyse and compare the ability of procalcitonin (PCT), C-reactive protein (CRP) and leukocytes to differentiate true bacteraemia from contaminated blood cultures in patients seen in the emergency department (ED) for an episode of infectious disease.

METHODS

Observational, retrospective and descriptive analytical study of all blood cultures with positive growth extracted in an ED in adult patients (≥18 years) during 2016 and 2017. The follow-up was carried out over a 30-day period to calculate the predictive power and the prognostic performance for true bacteraemia.

RESULTS

A total of 266 blood cultures with positive growth were included in the study. Out of these, 154 (57.9%) were considered true bacteraemia and 112 (42.1%) were considered to be contaminated blood cultures. The area under the Receiver Operating Characteristic curve (AUC-ROC) for PCT to predict true bacteraemia was 0.983 (95% CI: 0.972-0.994; P<0.001) and, considering a cut-off value of≥0.43 ng/ml, PCT achieved 94% sensitivity, 91% specificity, positive predictive value of 94%, and negative predictive value of 92%. The AUC-ROC obtained for CRP was 0.639 (95% CI: 0.572-0.707, P<.001), for leukocytes of 0.693 (95% CI: 0.630-0.756, P<.001) and for immature leukocytes (>10% bands) of 0.614 (95% CI: 0.547-0.682, P<.001). The mean values for PCT were 3.44 (SD 6.30) ng/ml in true bacteraemia vs. 0.16 (SD 0.18) ng/ml in contaminated blood cultures (P<.001).

CONCLUSIONS

In blood cultures with positive growth extracted in an ED, PCT achieves the best prognostic performance of true bacteraemia vs. contaminated blood cultures, better than CRP and leukocytes.

Usefulness and prognostic value of biomarkers in patients with community-acquired pneumonia in the emergency department

Between all patients treated in the Emergency Department (ED), 1.35% are diagnosed with community-acquired pneumonia (CAP). CAP is the main cause of death due to infectious disease (10-14%) and the most frequent reason of sepsis-septic shock in the ED. In the last decade, the search for objective tools to help establishing an early diagnosis, bacterial aetiology, severity, suspicion of bacteremia and the prognosis of mortality has increased. Biomarkers have shown their usefulness in this matter. Procalcitonin (obtains the highest accuracy for CAP diagnosis, bacterial aetiology and the presence of bacteremia), lactate (biomarker of hypoxia and tissue hypoperfusion) and proadrenomedullin (which has the greatest accuracy to predict mortality which in combination with the prognostic severity scales obtains even better results). The aim of this review is to highlight recently published scientific evidence and to compare the utility and prognostic accuracy of the biomarkers in CAP patients treated in the ED.