Chapter 4: Ventilator-Associated Events and Ventilator-Associated Pneumonia

Objectives

1. Compare ventilator-associated event (VAE), ventilator-associated condition (VAC), infection-related ventilator-associated complication (IVAC), and possible ventilator-associated pneumonia (PVAP).

2. Discuss strategies to prevent VAE.

3. Discuss the etiology of ventilator-associated pneumonia (VAP).

4. Describe care of the airway and ventilator circuit to avoid the development of VAP.

5. Discuss the roles of oral hygiene, noninvasive respiratory support, spontaneous awakening trials, spontaneous breathing trials, patient position, and the gastrointestinal tract on the development of VAP.

Introduction

In the past, ventilator-associated pneumonia (VAP) surveillance was considered an important safety metric. However, identification of VAP was not objective. As a result, reported VAP rates varied considerably among hospitals, with some reporting zero VAP. Moreover, the results of VAP surveillance were often not consistent with the clinical diagnosis of VAP used in patient care. In 2013, the Centers for Disease Control and Prevention (CDC) introduced a new surveillance approach for ventilator-associated events (VAE). A VAE is a deterioration in patient’s status that may be caused by an iatrogenic event, including not only VAP but also other complications of mechanical ventilation. This chapter covers VAE surveillance followed by a discussion of VAP.

Ventilator-Associated Events

This tiered approach first identifies a ventilator-associated condition (VAC). If a VAC is present, evaluation for an infection-related ventilator-associated complication (IVAC) is done. If an IVAC is present, evaluation is made for possible VAP (PVAP). The intent of these guidelines is to make VAE an objective approach to compare performance between institutions.

Ventilator-Associated Condition

A VAC is an increase in FIO₂ of more than or equal to 0.2 or an increase of more than or equal to 3 cm H₂O positive end-expiratory pressure (PEEP) that is sustained for more than or equal to 2 calendar days after a period of stability (Figure 4-1). The period of stability is defined as more than or equal to 2 calendar days where the FIO₂ and PEEP are stable or decreasing. The period of stability may be at the onset of intubation or any time during the course of invasive ventilation.

Infection-Related Ventilator-Associated Complication

The criteria for evaluation of IVAC are presented in Figure 4-2. IVAC occurs on or after day 3 of mechanical ventilation, and within 2 calendar days before or after the onset of worsening oxygenation, if both of the following criteria are met (1) temperature more than 38°C or less than 36°C, or white cell count more than or equal to 12,000 cells/mm³ or less than or equal to 4000 cells/mm³ and (2) a new antimicrobial agent is started ...