[Stressors for patients in the intensive care unit : An analysis taking controllability into consideration]

Studies on stress factors for patients in intensive care units (ICU) have so far concentrated on whether certain stressors have occurred or how stressful they were. There are no studies on stress for patients in ICUs that measured both the perception of stress and the chances perceived to control it; however, loss of control can result in long-term psychopathological consequences, such as depression or posttraumatic stress disorder. Therefore, a questionnaire was developed to evaluate the influence of controllability on perception of stress. The aim of this study was to answer the following questions: which situations were experienced as stressful by patients in ICUs, whether patients perceived them as being controllable and whether the experience of stress depended on the controllability? Furthermore, it was examined which stressful situations are specific to ICUs.

The questionnaire included 18 potentially stressful situations for ICU patients. These situations were assessed with respect to the occurrence, frequency and duration, the impact of stress and the perception of control. In addition, anxiety was assessed using STAI-X1. A total of 198 ICU patients and 100 patients hospitalized in a general surgery ward were interviewed.

Patients in ICUs remembered significantly more stressful situations than those on the normal ward (M ± SD = 10.2 ± 2.7 vs. 6.6 ± 2.0; d = 1.48; p < 0.001) and perceived them as more stressful (mean stress: M ± SD = 3.6 ± 1.5 vs. 2.2 ± 1.3; d = 1.01; p < 0.001). The most stressful situations for ICU patients were fixation of the arms (M ± SD = 7.47 ± 3.27), mechanical ventilation (M ± SD = 7.36 ± 3.29) and endotracheal suctioning (M ± SD = 7.19 ± 2.99). Approximately one third of patients underwent these situations. Situations experienced by more than 90% of ICU patients were evaluated as being the least stressful experiences, including infusion (M ± SD = 2.7 ± 2.7), measuring heart activity (M ± SD = 2.3 ± 2.7), taking blood samples (M ± SD = 2.2 ± 2.7), and temperature control (M ± SD = 0.9 ± 1.7). Controllability experienced by ICU patients negatively correlated with anxiety (r = -0.20, p = 0.004) and mean sensation of stress (r = -0.36; p < 0.001). When comparing stress levels of ICU patients who perceived controllability in a given situation to those who did not, the greatest effects (Cohen's d > 1.4) were observed for the situations presence of a bed barrier (M ± SD = 0.1 ± 0.4 vs. 5.9 ± 2.8), lighting at night (M ± SD = 0.7 ± 1.7 vs. 5.7 ± 3.3), presence of a ventilation tube (M ± SD = 2.5 ± 2.1 vs. 6.7 ± 3.0) and repositioning of the patient (M ± SD = 2.5 ± 2.9 vs. 6.7 ± 2.9).

The experience of loss of control seems to negatively modify the impact of stressors. Thus, an increase in aspects of controllability could reduce the burden on patients during intensive care.