Ventilator-associated pneumonia is an important risk factor for mortality after major cardiac surgery

doi:10.1016/j.jcrc.2011.03.008

Journal of Critical Care

Volume 27, Issue 1, February 2012, Pages 18-25

https://doi.org/10.1016/j.jcrc.2011.03.008 Get rights and content

Abstract

Purpose

Ventilator-associated pneumonia (VAP) is the main infectious complication in cardiac surgery patients and is associated with an important increase in morbidity and mortality. The aim of our study was to analyze the impact of VAP on mortality excluding other comorbidities and to study its etiology and the risk factors for its development.

Materials and Methods

This prospective cohort study included 1610 postoperative cardiac surgery patients' status post cardiopulmonary bypass (CPB) between July 2004 and January 2008. The primary outcome measures were the development of VAP and in-hospital mortality.

Results

Ventilator-associated pneumonia was observed in 124 patients (7.7%). Patients with VAP had a longer length of hospitalization (40.7 ± 35.1 vs 16.1 ± 30.1 days, P < .0001) and greater in-hospital mortality (49.2% [61/124] vs 2.0% [30/1486], P = .0001) in comparison with patients without VAP. After performing the Cox multivariant analysis adjustment, VAP was identified as the most important independent mortality risk factor (adjusted hazard ratio [HR], 8.53; 95% confidence interval, 4.21-17.30; P = .0001). Other independent risk factors of in-hospital mortality were chronic renal failure (HR, 2.56), diabetes mellitus (HR, 1.90), CPB time (HR, 1.51), respiratory failure (HR, 2.13), acute renal failure (HR, 2.39), and mediastinal bleeding of at least 1000 mL (HR, 1.81).

Conclusions

The development of VAP after CPB is the most important independent risk factor for in-hospital mortality. Identification of effective strategies for the prevention of VAP is needed.

Introduction

Ventilator-associated pneumonia (VAP) is the most frequent serious infection among patients undergoing heart surgery. The prevalence of VAP is estimated to be 7.8% to 21.6% [1], [2], [3] and is associated with prolonged hospitalization [4], [5], increased health care costs [6], and a 15% to 45% attributable mortality [7].

In patients admitted to the intensive care unit (ICU), the extra mortality due to VAP remains a controversial issue in the literature. Previous studies have reached conflicting conclusions regarding the impact of VAP on mortality [1], [8], [9], [10], [11], [12], [13], [14], [15], [16], [17]. Although the gross mortality rate is high, there are doubts as to whether the higher mortality rate is due to VAP itself or to the seriousness of the underlying illness.

Patients undergoing heart surgery are at a particularly high risk for the development of VAP due to the presence of multiple comorbidities, frequent postoperative use of invasive devices (eg, intraaortic balloon counterpulsation, pulmonary artery catheter), and the common use of cardiopulmonary bypass (CPB). At the same time, in-hospital patients are also at risk for multiple postoperative events (eg, myocardial infarction [MI], congestive heart failure, acute renal failure, strokes) [1], [2], [3], [4], [16], [18], [19]. These comorbidities complicate the evaluation of the impact of VAP on mortality [17]. The repercussions of VAP on in-hospital mortality have not been adequately studied in the area of cardiac surgery.

Our working hypothesis was that VAP is the most important independent risk factor of in-hospital mortality in cardiac surgery patients. Our main objective was to assess whether the development of VAP during the postoperative period after cardiac surgery for patients undergoing CPB is associated with an excess of in-hospital mortality not attributable to the underlying severity of the illness or to the intraoperative and postoperative events. The secondary aim was to establish risk factors of in-hospital mortality.

Section snippets

Hospital setting and patients

This prospective observational study was carried out in the “Hospital Clínico Universitario,” a tertiary-level medical center with 800 beds in Valladolid, Spain. The Department of Cardiac Surgery annually performs approximately 550 open cardiac operations with extracorporeal circulation in adult patients. Two operating rooms were routinely used. There was an ICU with 10 beds dedicated exclusively to the postoperative care of patients who had undergone cardiac surgery. During a 3.5-year period

Patient and disease characteristics

During the period of the study, a total of 1610 patients were included. Mean patient age was 67.8 ± 10.3 years. There were 60.9% (980/1610) men and 39.1% (630/1610) women. Ventilator-associated pneumonia after cardiac surgery developed in 124 (7.7%) of patients, and the mean interval from surgery to presentation of VAP was 5.7 ± 5.8 days. In 80 (64%) patients, the antibiotic therapy was appropriate.

Patients with VAP (Table 1) had more comorbid conditions, longer aortic cross-clamp time (P <

Discussion

This prospective cohort study was designed to examine any potential effect of VAP on the in-hospital mortality of patients undergoing cardiac surgery with CPB and to differentiate this from the contributing factors concerning preoperative, intraoperative, and postoperative complications. In this context, the most relevant findings were that (1) the development of VAP during postoperative cardiac surgery is an important factor in determining in-hospital mortality, increasing the risk of death by

References (43)

M.H. Rebollo et al.
Nosocomial infections in patients having cardiovascular operations: a multivariate analysis of risk factors
J Thorac Cardiovasc Surg
(1996)
J. Rello et al.
Epidemiology and outcomes of ventilator-associated pneumonia in a large US database
Chest
(2002)
J.Y. Fagon et al.
Nosocomial pneumonia in ventilated patients: a cohort study evaluating attributable mortality and hospital stay
Am J Med
(1993)
E. Tamayo et al.
Comparative study of single-dose and 24-hour multiple-dose antibiotic prophylaxis for cardiac surgery
J Thorac Cardiovasc Surg
(2008)
J.S. Garner et al.
CDC definitions for nosocomial infections
Am J Infect Control
(1988)
M.H. Kollef et al.
The impact of nosocomial infections on patient outcomes following cardiac surgery
Chest
(1997)
M.H. Kollef
Ventilator-associated pneumonia: a multivariate analysis
JAMA
(1993)
E. Bouza et al.
Ventilator-associated pneumonia after heart surgery: a prospective analysis and the value of surveillance
Crit Care Med
(2003)
N. Bercault et al.
Mortality rate attributable to ventilator-associated nosocomial pneumonia in an adult intensive care unit: a prospective case-control study
Crit Care Med
(2001)
D.K. Warren et al.
Outcome and attributable cost of ventilator associated pneumonia among intensive care unit patients in a suburban medical center
Crit Care Med
(2003)

P.A. Gross et al.

Nosocomial infections and hospital deaths: a case control study

Am J Med

(1983)

C.P. Craig et al.

Effect of intensive care unit nosocomial pneumonia on duration of stay and mortality

Am J Infect Control

(1993)

D.E.. Craven et al.

Nosocomial infection and fatality in medical and surgical intensive care unit patients

Arch Intern Med

(1988)

D.E. Craven et al.

Risk factors for pneumonia and fatality in patients receiving continuous mechanical ventilation

Am Rev Respir Dis

(1986)

J.L. Vincent et al.

The prevalence of nosocomial infection in intensive care units in Europe: results of the European prevalence of infection in intensive care (EPIC) study

JAMA

(1995)

J.Y. Fagon et al.

Nosocomial pneumonia and mortality among patients in intensive care units

JAMA

(1996)

L. Papazian et al.

Effect of ventilator-associated pneumonia on mortality and morbidity

Am J Respir Crit Care Med

(1996)

R. Bueno-Cavanillas et al.

Influence of nosocomial infection on mortality rate in an intensive care unit

Crit Care Med

(1994)

J. Vallés et al.

Excess ICU mortality attributable to ventilator-associated pneumonia: the role of early vs late onset

Intensive Care Med

(2007)

W.G. Melsen et al.

Ventilator-associated pneumonia and mortality: a systematic review of observational studies

Crit Care Med

(2009)

S.R. Leal-Noval et al.

Nosocomial pneumonia in patients undergoing heart surgery

Crit Care Med

(2000)

Cited by (47)

Sepsis after cardiac surgery: The clinical challenge. Review article
2021, Acta Colombiana de Cuidado Intensivo
Sepsis continues to be a clinical condition with an ostensibly high mortality despite efforts in early detection and therapeutic interventions, and its incidence in the post-surgical cardiac surgery patient is relatively low. However, when sepsis or septic shock develops in this scenario, it has a negative impact on the results. Regardless of the procedure performed, the success of the outcomes depends on the optimal postoperative care in the Intensive Care Unit, in order to improve the results and to have an effect on the morbidity and mortality.
To carry out a review of sepsis in the scenario of the post-surgical cardiovascular patient, its pathophysiology, risk factors, integral management, and the results of different therapeutic strategies in the light of current evidence.
A search was conducted in the main scientific databases (Web of Science/Scopus/PubMed/SciELO/Lilacs/Google Scholar) for review articles of sepsis in cardiac surgery, as well as studies that included targeted treatments, and antibiotic prophylaxis in this clinical context.
Bibliographic references were found in databases from 1996 to 2019.
Sepsis after cardiac surgery is a rare event. There are no different definitions for this group of patients and there are difficulties in diagnosis since the manifestations of septic shock can be confused with the normal postoperative course. Different prevention strategies for postoperative infections are recognized in clinical practice guidelines.
La sepsis continúa siendo una condición clínica con una mortalidad ostensiblemente alta a pesar de los esfuerzos en la detección temprana y las intervenciones terapéuticas, y su incidencia en el paciente posquirúrgico de cirugía cardiaca es relativamente baja, sin embargo, cuando se desarrolla sepsis o choque séptico en este escenario, tiene un impacto negativo en los resultados. Independientemente del procedimiento realizado, el éxito de los resultados depende de la atención postoperatoria óptima en la unidad de cuidados intensivos, con el fin de mejorar los resultados y obtener un impacto en relación con la morbimortalidad.
Realizar una revisión sobre la sepsis en el escenario del paciente posquirúrgico cardiovascular, su fisiopatología, los factores de riesgo, el manejo integral y los resultados de diferentes estrategias terapéuticas a la luz de la evidencia actual.
Se realizó una búsqueda en las principales bases de datos científicas (Web of Science/Scopus/PubMed/SciELO/Lilacs/Google Scholar) sobre artículos de revisión de sepsis en cirugía cardiaca, y estudios que incluyeron tratamientos dirigidos y profilaxis antibiótica en este contexto clínico.
Se encontraron referencias bibliográficas en bases de datos desde 1996 hasta 2019.
La sepsis después de la cirugía cardiaca es un evento raro, no existen definiciones diferentes para este grupo poblacional y hay dificultades en el diagnóstico dado que las manifestaciones del choque séptico se pueden confundir con el curso normal del postoperatorio. Se reconoce en las guías de la práctica clínica diferentes estrategias de prevención para las infecciones postoperatorias.
Risk factors for ventilator-associated pneumonia following cardiac surgery
2020, Journal of Hospital Infection
Ventilator-associated pneumonia (VAP) following cardiac surgery is a preventable complication associated with adverse outcomes.
We aimed to assess risk factors and outcomes of VAP following cardiac surgery.
A matched 1:3 case:control study, including adult patients undergoing cardiac surgery through sternotomy between September 2014 and March 2017 was conducted in a tertiary-care hospital in Israel. Cases included all patients developing VAP within 30 days after surgery, defined using consensus criteria. Controls were matched for age, gender and surgery type. Operative data were collected prospectively, other data were collected retrospectively. Cox regression was used for adjusted analysis of matched data.
Out of 946 operated patients, we identified 57 patients with VAP after cardiac surgery (17.7 episodes per 1000 ventilator-days) matched to 149 controls. Significant independent risk factors for VAP included congestive heart failure (odds ratio (OR) 2.357, 95% confidence interval (CI) 1.052–5.281), chest re-exploration in the intensive care unit (OR 10.213, 95% CI 2.235–46.678), preoperative glucose levels (OR 1.1010 per 1 mg/dL increase 95% CI 1.004–1.019) intraoperative red blood cell transfusions (OR 1.542 per 1 unit, 95% CI 1.109–2.094) and pulmonary hypertension (OR 2.261, 95% CI 1.048–6.554). VAP was most commonly caused by Gram-negative pathogens. VAP was associated with higher mortality, longer length of stay, longer need for ventilator support and longer stay in ICU setting.
Postoperative VAP in cardiac surgery patients is associated with severe clinical outcomes. We identified risk factors that can aid in preventive measures implementation for high-risk patients.
Prophylactic Noninvasive Ventilation Versus Conventional Care in Patients After Cardiac Surgery
2020, Journal of Surgical Research
Citation Excerpt :
A prevalence of PPCs from 5% to 20% has been documented.1 It has been demonstrated that PPCs are associated with increased postoperative morbidity and mortality.2,3 Therefore, exploring how to prevent and reduce the rate of PPCs has been a research focus.
Cardiac surgery can be accompanied by postoperative complications, which are associated with increased postoperative morbidity and mortality. Therefore, it is necessary to investigate the effect of prophylactic noninvasive ventilation (NIV) after extubation versus conventional pulmonary care on complications after cardiac surgery.
An electronic search of PubMed, Cochrane Library, Ovid, and EMBASE was conducted to find randomized controlled trials which compared the effect of prophylactic NIV with controlled strategies on complications and which were published before April 2018.
Ten studies (1011 patients) were included in the final analysis. The atelectasis rate was 32.6% in the prophylactic-NIV group, which was lower than that in the control group (48.71%). Prophylactic NIV could lower the rate of atelectasis, reintubation, and other respiratory complications (pleural effusion, pneumonia, and hypoxia) (odds ratio = 0.43, 0.33, and 0.45; 95% confidence interval: 0.21-0.88, 0. 13-0.84, 0.27-0.75; P = 0.02, 0.02, and 0.002, respectively). The effect on cardiac and distal organ complications (P = 0.07) and hospital mortality (P = 0.62) might be limited.
Prophylactic NIV is associated with a lower rate of postoperative pulmonary complications. The effect on the other complications and hospital mortality might be limited. Further evidence with randomized controlled trials can discern the benefits.
Postoperative kidney oxygen saturation as a novel marker for acute kidney injury after adult cardiac surgery
2019, Journal of Thoracic and Cardiovascular Surgery
Acute kidney injury is a severe complication and one of the stronger risk factors for death in patients undergoing cardiac surgery. The relationship between postoperative brain oxygen saturation and kidney oxygen saturation with acute kidney injury in adults undergoing cardiac surgery has not been determined. We designed a single-center prospective study to determine if the continuous monitoring of postoperative brain oxygen saturation and kidney oxygen saturation could predict postoperative acute kidney injury.
We conducted a prospective open cohort study from January to September 2017. The primary outcome was postoperative acute kidney injury using the Kidney Disease: Improving Global Outcomes criteria. Brain oxygen saturation and kidney oxygen saturation, the metrics of which were area measurements (%-min), were recorded during the surgery and the first 48 hours after the cardiac procedure. Receiver operating characteristic curve analysis was used to evaluate the predictive power of kidney oxygen saturation for acute kidney injury.
A total of 121 consecutive patients were enrolled. Thirty-five patients (28.9%) developed acute kidney injury. Brain oxygen saturation showed no statistical difference in both groups; however, kidney oxygen saturation was related to acute kidney injury (P = .001). Receiver operating characteristic curve analysis showed that kidney oxygen saturation could predict the risk of acute kidney injury. Kidney oxygen saturation less than 65% (area under the curve-receiver operating characteristic, 0.679 ± 0.054, 95% confidence interval, 0.573-0.785, P = .002) and 20% decrease from baseline (area under the curve-receiver operating characteristic, 0.639 ± 0.059, 95% confidence interval, 0.523-0.755, P = .019) showed the better performance, respectively.
Postoperative kidney oxygen saturation is related to the development of cardiac surgery–associated acute kidney injury. Continuous kidney saturation monitoring might be a promising, noninvasive tool for predicting acute kidney injury during the postoperative period for adult patients after cardiac surgery.
Impact of an ultraviolet air sterilizer on cardiac surgery patients, a randomized clinical trial
2018, Medicina Clinica
Citation Excerpt :
Ventilator-associated pneumonia (VAP) is one of the most common hospital-acquired infections associated with high mortality, affecting 9–27% of all intubated patients.9 It is developed when opportunistic bacterial pathogens, such as Pseudomonas spp., Acinetobacter spp., Enterobacteriaceae, Streptococci spp., Haemophilus spp., and methicillin-resistant strains of Staphylococcus aureus, reach the pulmonary system of a patient under mechanical ventilation.9,10 VAP is associated with a longer hospital stay, higher mortality rates, and increased healthcare costs.11
Numerous studies have evaluated the use of ultraviolet-C devices for terminal disinfection in hospitals, however, to date there is little information about the device's final impact on patients. We investigated the effect of an ultraviolet air sterilizer (UVAS) on the clinical outcomes of cardiac surgery patients.
This random, prospective and non-interventional study included 1097 adult patients undergoing elective cardiac surgery: 522 stayed in an ICU room with UVAS (Medixair^®) and 575 patients ICU room without UVAS and were used as a control. The primary outcome measure was to evaluate the effect of a UVAS on the overall prevalence of nosocomial infections in postoperative cardiac patients in ICUs.
No significant differences in ventilator-associated pneumonia (4.6% vs. 5.0%, p = 0.77) and total infection (14.0% vs. 15.5%, p = 0.45) rates were detected in patients with and without the UVAS. The length of stay in the intensive care unit and at the hospital was similar in both groups, UVAS (4.6 (8.2) days and 18.3 (5.5) days) and without UVAS (4.6 (7.3) days and 19.2 (18.6) days). The 30-day in-hospital mortality rate was 5.3%, no significant differences between groups were observed (p = 0.053).
Novel ultraviolet-C technology has not been shown to significantly reduce nosocomial infections or mortality rates in cardiac surgery patients.
Numerosos estudios han evaluado el uso de dispositivos ultravioleta C para la desinfección terminal en hospitales; sin embargo, hasta la fecha existen pocos datos sobre el impacto en los pacientes. Hemos evaluado el efecto de un esterilizador de aire ultravioleta (UVAS) sobre las variables clínicas de los pacientes operados de cirugía cardíaca.
Este estudio prospectivo, aleatorizado no intervencional incluyó 1.097 pacientes adultos intervenidos de cirugía cardíaca electiva: 522 ingresaron en una habitación de UCI con UVAS (Medixair^®) y 575 pacientes en habitación de UCI sin UVAS se utilizaron como control. La variable principal medida fue el efecto del UVAS sobre la prevalencia global de infecciones en el postoperatorio de cirugía cardíaca en UCI.
No hubo diferencias significativas en la neumonía asociada a ventilación mecánica (4,6% vs. 5,0%, p = 0,77) e índices totales de infección (14,0% vs. 15,5%, p = 0,45) detectados en pacientes con y sin UVAS. La duración del ingreso en UCI y en el hospital fue similar en ambos grupos, UVAS (4,6 [8,2] días y 18,3 [5,5] días) y sin UVAS (4,6 [7,3] días y 19,2 [18,6] días). La mortalidad a 30 días hospitalaria fue del 5,3%, sin diferencias significativas entre los grupos (p = 0,053).
Conclusión La nueva tecnología ultravioleta C no ha demostrado disminuir las infecciones nosocomiales ni la mortalidad en pacientes de cirugía cardíaca.
Procalcitonin and white blood cells, combined predictors of infection in cardiac surgery patients
2017, Journal of Surgical Research
Citation Excerpt :
Most previous studies have indicated that PCT alone does not aid in predicting the development of infection.11,25,26,28 The cutoff value for PCT as a biomarker of infection ranges from 0.5-1.5 ng/mL.9,29 Jebali et al. took the maximum value of each biomarker on the third postoperative day or later, using the ROC curve to identify the best cutoff value for each biomarker to diagnose infection.
Sepsis is strongly associated with an increased risk of postoperative mortality, longer length of hospital stay, and elevated health care costs. Early clinical symptoms overlap with those of systemic inflammatory response syndrome, a response that commonly occurs after cardiac surgery with cardiopulmonary bypass. Since a combination of biomarkers has been demonstrated to improve the prediction of postoperative infection, the objective of the present study was to test whether the combination of C-reactive protein (CRP), white blood cells (WBC), and procalcitonin (PCT) is able to predict postoperative infection in a large cohort of cardiac surgery patients.
Case-control study involving 423 patients who underwent cardiac surgery with cardiopulmonary bypass. Patients were retrospectively classified into two groups based on whether they developed severe sepsis or septic shock during the postoperative period. Blood samples for biological measurements (PCT, CRP, and WBC) were drawn on the first day in the intensive care unit, then once daily in the morning until the 10th postoperative day.
CRP median values were similar in both groups. WBC and PCT median values were significantly higher in patients with infection than without during the first 10 postoperative days. With elevation cutoffs ≤3 times (OR: 4.058; 95% CI: 2.206-7.463; P = 0.001) and ≥4 times (OR: 10.274, 95% CI: 3.690-28.604; P < 0.001), the median value for PCT (1.7 ng/mL) and/or WBC (13,000 cells/mm³) on the second postoperative day was significantly associated with the development of infection.
The goal of this study was to use a large cohort of cardiac surgery patients to ensure that the results were representative of this population. The combination of PCT and WBC levels over the first three postoperative days was able to predict postoperative infection within the 30 d following cardiac surgery.

View all citing articles on Scopus

^☆: Funding sources: This work was supported in part by a grant from the “Gerencia de Salud, Consejería de Sanidad, Junta de Castilla y Leon” (GRS 143/A/07) and the Ministry of Health (RD06/0001/0020). All the authors carefully read the manuscript and fully approved it. The manuscript is original, and it is not submitted anywhere other than your journal. The authors declare not having conflict of interest regarding this study.

^☆☆: Contribution of authors: ET and FJA conceived the idea, designed the protocol, and supervised the analysis of the results. JB and BMR contributed to obtain the funding, oversaw the study, and acted as guarantors for the report. BMR, JB, JFBM, JC, JME, FJA, ET, JC, and JIGH helped in the conception of the study and the design of the protocol, supervised the recruitment of patients, collected the clinical material, and were responsible for statistical analysis. ET, IF, MH, FJA, and JB developed and supervised all work and analyzed the results. ET wrote the report in collaboration with FJA, JIGH, JB, and the other authors.

View full text

Ventilator-Associated Pneumonia/Mechanical VentilationVentilator-associated pneumonia is an important risk factor for mortality after major cardiac surgery☆,☆☆

Abstract

Purpose

Materials and Methods

Results

Conclusions

Introduction

Section snippets

Hospital setting and patients

Patient and disease characteristics

Discussion

J Thorac Cardiovasc Surg

Chest

Am J Med

J Thorac Cardiovasc Surg

Am J Infect Control

Chest

Ventilator-associated pneumonia: a multivariate analysis

JAMA

Ventilator-associated pneumonia after heart surgery: a prospective analysis and the value of surveillance

Crit Care Med

Mortality rate attributable to ventilator-associated nosocomial pneumonia in an adult intensive care unit: a prospective case-control study

Crit Care Med

Outcome and attributable cost of ventilator associated pneumonia among intensive care unit patients in a suburban medical center

Crit Care Med

Nosocomial infections and hospital deaths: a case control study

Am J Med

Effect of intensive care unit nosocomial pneumonia on duration of stay and mortality

Am J Infect Control

Nosocomial infection and fatality in medical and surgical intensive care unit patients

Arch Intern Med

Risk factors for pneumonia and fatality in patients receiving continuous mechanical ventilation

Am Rev Respir Dis

The prevalence of nosocomial infection in intensive care units in Europe: results of the European prevalence of infection in intensive care (EPIC) study

JAMA

Nosocomial pneumonia and mortality among patients in intensive care units

JAMA

Effect of ventilator-associated pneumonia on mortality and morbidity

Am J Respir Crit Care Med

Influence of nosocomial infection on mortality rate in an intensive care unit

Crit Care Med

Excess ICU mortality attributable to ventilator-associated pneumonia: the role of early vs late onset

Intensive Care Med

Ventilator-associated pneumonia and mortality: a systematic review of observational studies

Crit Care Med

Nosocomial pneumonia in patients undergoing heart surgery

Crit Care Med

Ventilator-Associated Pneumonia/Mechanical Ventilation
Ventilator-associated pneumonia is an important risk factor for mortality after major cardiac surgery☆,☆☆