Predictors and outcome of early-onset pneumonia after out-of-hospital cardiac arrest

Abstract

Background: Early-onset pneumonia (EOP) after out-of-hospital cardiac arrest is frequently observed. Causative factors are loss of airway protection during cardiac arrest, pulmonary contusion, and emergency airway management. We assessed the incidence, risk factors, and clinical course of EOP, and evaluated the impact of an early exchange of the prehospitally inserted endotracheal tube (ETT).

Methods: In our retrospective analysis we included 104 consecutive subjects admitted to our ICU after out-of-hospital cardiac arrest between 2007 and 2012. All subjects underwent therapeutic hypothermia. We analyzed clinical course, inflammation indicators, Clinical Pulmonary Infection Score, occurrence of EOP, duration of ventilatory support, microbiological findings, and short-term outcome.

Results: Of the 104 subjects, 46.2% received an exchange of ETT directly after hospital admission. Neither ETT exchange nor observed aspiration were associated with elevated CPIS or EOP, nor with proof of microorganisms in respiratory secretions. We found no differences in duration of ventilatory support, P(aO2)/F(IO2), ICU days, or outcome. C-reactive protein was significantly higher in subjects with aspiration (P = .046). Sex, age, smoking status, aspiration, cause of cardiac arrest, first detected heart rhythm, and use of supraglottic airways devices were not associated with EOP. Subjects with EOP had a longer need for ventilatory support (P = .005), higher tracheotomy rate (P = .03), longer ICU stay (P = .005), higher C-reactive protein (P < .001), higher body temperature (P = .003), higher Clinical Pulmonary Infection Score (P < .001), and lower P(aO2)/F(IO2) (P = .008).

Conclusions: The rate of EOP was not significantly influenced by the exchange of the preclinically inserted ETT, but was associated with longer need for mechanical ventilation and ICU stay.

Keywords: Clinical Pulmonary Infection Score; airway management; airway protection; aspiration; cardiac arrest; emergency; endotracheal tube; pneumonia.