Patterns of anxiety in critically ill patients receiving mechanical ventilatory support

Abstract

Background: Mechanical ventilation is one of the most frequently used technological treatments in critical care units and induces great anxiety in patients.

Objectives: Although mechanical ventilation and critical illness induce great anxiety and distress in hospitalized patients, little is known about anxiety ratings over the course of ventilatory support. Knowledge of anxiety ratings over time is needed to implement effective symptom management interventions. The purposes of this study were to describe anxiety ratings for a subgroup of mechanically ventilated patients over the duration of enrollment in a multisite clinical trial, to discern any pattern of change in anxiety ratings, to determine if anxiety decreases over time, and to explore the influence of sedative exposure on anxiety ratings.

Methods: Participants were 57 mechanically ventilated patients who were randomly assigned to the usual care group of a randomized controlled trial designed to assess the efficacy of music interventions on anxiety of mechanically ventilated patients in intensive care units. Anxiety ratings were obtained at study entry and daily for up to 30 days. A 100-mm visual analog scale was used to measure anxiety. Visual Analog Scale-Anxiety scores were plotted as a function of study time in days for each participant to discern possible patterns of change. A mixed-models analysis was performed to assess the nature and magnitude of change over time (slope) using 251 observations on 57 patients.

Results: Results of the unconditional means model indicated that further modeling was appropriate. An autoregressive covariance structure with a random component for participant was chosen as the most appropriate covariance structure for modeling. An unconditional growth model indicated that the Visual Analog Scale-Anxiety ratings declined slowly over time: -.53 points per day (p = .09).

Discussion: Anxiety is an individual patient experience that requires ongoing management with appropriate assessment and intervention over the duration of mechanical ventilatory support.

Figure 1. Summary of Trajectories of Anxiety (VAS-A scores) over Day of Study (N = 31)

Note These graphs are for those subjects who had at least 3 days of VAS-A scores. Graphs are presented by the total number of days in the study with VAS-A scores. These graphs emphasize the great variability in VAS-A scores over time, with no definite pattern of change evident.

Figure 2. Number of Participants Providing Anxiety Ratings (VAS-A) by Day of Study

NoteFirst day of VAS-A data was not always the first day enrolled in the study; 47 participants had their first anxiety data collection on Day 1, 8 participants on Day 2 and 2 participants on Day 3 (total N = 57 participants with VAS-A data).

Figure 3

Median Anxiety Ratings and Sedation Dose Frequency over Day of Study

Figure 4

Median Anxiety Ratings and Sedation Intensity Score over Day of Study