Intubation Setting, Aspiration, and Ventilator-Associated Conditions

Steven Talbert, PhD, RN; Christine Wargo Detrick, MSN, RN; Kimberly Emery, BSN, RN; Aurea Middleton, BSN, RN; Bassam Abomoelak, PhD, MSc, MT(AAB); Chirajyoti Deb, MSc, PhD; Devendra I. Mehta, MD; Mary Lou Sole, PhD, RN, CCNS, CNL


Am J Crit Care. 2020;29(5):371-378. 

In This Article

Abstract and Introduction


Background: Patients experience endotracheal intubation in various settings with wide-ranging risks for postintubation complications such as aspiration and ventilator-associated conditions.

Objectives: To evaluate associations between intubation setting, presence of aspiration biomarkers, and clinical outcomes.

Methods: This study is a subanalysis of data from the NO-ASPIRATE single-blinded randomized clinical trial. Data were prospectively collected for 513 adult patients intubated within 24 hours of enrollment. Patients with documented aspiration events at intubation were excluded. In the NO-ASPIRATE trial, intervention patients received enhanced oropharyngeal suctioning every 4 hours and control patients received sham suctioning. Tracheal specimens for α-amylase and pepsin tests were collected upon enrollment. Primary outcomes were ventilator hours, lengths of stay, and rates of ventilator-associated conditions.

Results: Of the baseline tracheal specimens, 76.4% were positive for α-amylase and 33.1% were positive for pepsin. Proportions of positive tracheal α-amylase and pepsin tests did not differ significantly between intubation locations (study hospital, transfer from other hospital, or field intubation). No differences were found for ventilator hours or lengths of stay. Patients intubated at another hospital and transferred had significantly higher ventilator-associated condition rates than did those intubated at the study hospital (P = .02). Ventilator-associated condition rates did not differ significantly between patients intubated in the field and patients in other groups.

Conclusions: Higher ventilator-associated condition rates associated with interhospital transfer may be related to movement from bed, vehicle loading and unloading, and transport vehicle vibrations. Airway assessment and care may also be suboptimal in the transport environment.


Oral endotracheal intubation is performed in a variety of settings with different airway access complexities. Operating room intubations are usually more controlled, whereas emergency department and prehospital (field) intubations are more urgent and less controlled. Environmental conditions, lighting, and the working space further complicate oral endotracheal intubation and airway management in the prehospital and interfacility transfer environments.[1–3]

Oral endotracheal intubation is not without risks, with aspiration being one of the most common risks.[4–7] Clinical complications associated with aspiration include ventilator-associated conditions (VACs) and ventilator-associated pneumonia, which are leading causes of increased morbidity and mortality in critically ill patients.[4,8,9] Detection of aspiration events is often difficult. One emerging technique is analyzing tracheal secretions for α-amylase (an oral digestive enzyme) and pepsin A (a gastric digestive enzyme).[10–13] The presence of these enzymes may reflect aspiration events in which microbes, acids, and other oral and gastric contents enter the lungs.

Emerging techniques for detecting aspiration include analyzing tracheal secretions for α-amylase and pepsin A.

Studies evaluating associations between tracheal α-amylase or pepsin levels and clinical outcomes following prehospital intubation are limited,[4] and no published studies have examined these biomarkers in patients experiencing interfacility transport. Differences in urgency and intubation circumstances of the prehospital setting and the environmental conditions associated with interfacility transport may put patients intubated in these settings at greater risk for aspiration and aspiration-associated complications. The purpose of this study was to evaluate the association between the presence of aspiration biomarkers and clinical outcomes in patients intubated in different settings.