Major Article
Risk factors for ventilator-associated events: A prospective cohort study

https://doi.org/10.1016/j.ajic.2018.09.032Get rights and content

Highlights

  • Ventilator-associated events (VAEs) are associated with prolonged mechanical ventilation.

  • VAEs are associated with hospital death.

  • VAEs are closely related to the evaluation of medical and nursing quality.

  • Few articles look for VAE risk factors.

  • Risk factors were evaluated for VAE prospectively.

Background

In January 2013, the Centers for Disease Control and Prevention released new surveillance definitions for ventilator-associated event (VAE) to replace ventilator-associated pneumonia (VAP) in adult patients. VAEs are associated with prolonged mechanical ventilation and hospital death, but little is known about their risk factors and how best to prevent them.

Methods

We compared VAE cases with non-VAE cases with regard to demographics, comorbidities, sedative exposures, opioids exposures, paralytic exposures, routes of nutrition, blood products, gastric retention, and fluid balance. Patients mechanically ventilated for ≥4 days between January 1, 2017, and December 31, 2017, in 2 adult intensive care units of a tertiary care teaching hospital in China were included.

Results

On multivariable logistic regression, significant risk factors for VAEs were positive daily fluid balances of ≥ 50 mL between day of intubation and the fourth day of mechanical ventilation (relative risk [RR], 8.39; 95% confidence interval [CI], 2.99-23.50), sedative administered between the first day and the fourth day of invasive mechanical ventilation (RR, 15.69; 95% CI, 1.62-152.06), and daily gastric retention of ≥200 mL between day of intubation and the fourth day of mechanical ventilation (RR, 9.27; 95% CI, 1.89-45.47).

Conclusions

Positive daily fluid balances of ≥50 mL, sedatives administered, and gastric retention of ≥200 mL are risk factors for VAEs. Intervention studies are needed to determine if targeting these risk factors can lower VAE rates.

Section snippets

Study design

We prospectively investigated patients' electronic medical records to identify demographics, medications, and laboratory values. We referred to the VAE data collection and antimicrobial worksheet recommended by the CDC. On the worksheet, we recorded the information of patients with tracheal intubation or tracheostomy who were invasively mechanically ventilated ≥4 days, including acute physiology and chronic health evaluation score II (APACHE II score), comorbidities, daily minimum positive

RESULTS

During the study period, a total of 5,532 patients were enrolled. A total of 428 patients met the inclusion criteria. The number of mechanical ventilation episodes was 523 times, the total number of hospitalization days was 11,079, and the total number of IMV days was 3,982. There were 30 VACs, 14 IVACs, and 9 possible VAPs (7.53, 3.52, and 2.26 events per 1,000 ventilator days, respectively). Figure 1 shows the median time to VAC was 6 days (interquartile range, 4.25-9.00 days).

DISCUSSION

CDC's new VAE definitions allow objective and reproducible surveillance for complications of mechanical ventilation. The goal of this study was to identify risk factors for VAEs that might inform prevention strategies in the east of China through prospective research methods. We identified 3 significant risk factors for VAEs. Sedatives ordered between the first day and the fourth day of IMV, average gastric retention ≥200 mL, and greater net fluid balance between day of intubation and the

CONCLUSIONS

This study identifies potentially modifiable patterns of care associated with VAEs. Sedatives administered between the first day and the fourth day of IMV, gastric retention, and positive fluid balance between day of intubation and the fourth day of IMV are significant risk factors for VAEs. These risk factors are potentially targets for intervention. Prospective studies are now warranted to test whether strategies targeting these risk factors can reduce VAE rates and improve the outcome of

Acknowledgments

We would like to thank Renxu Zhai and Xinzhong Zhao from the Infection Control Team of The Affiliated Hospital of Xuzhou Medical University for checking data during the study period. We would also like to thank Dr Lang Zhuo from the Clinical Research Support Center of Xuzhou Medical University for statistical support.

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      These were excessive fluid accumulation from day 1 of intubation to day 7 of invasive mechanical ventilation (Odds Ratio 30.92) and greater number of days with vasopressor support (Odds Ratio 1.92). Our review of literature revealed only one recent prospective study on adult critically ill patients by Liu et al where they have measured daily fluid balance and found that ≥50 ml of positive fluid balance is significantly associated with the risk of acquiring VAE [11]. A growing body of evidence has highlighted the potential detrimental effects of a large volume of fluids after initial resuscitation of patients in the ICU [12].

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    Funding/support: This study was supported by the Preventive Medicine Research Fund from the Jiangsu Provincial Health and Family Planning Commission (grant number Y2015067).

    Conflicts of interest: None to report.

    Author contributions: J.L. and S.Z. contributed equally to this article.

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