Assessment of Anxiety in Intensive Care Patients
Background: Anxiety is difficult to detect in patients receiving mechanical ventilation because clinical signs are confounded and patients often cannot respond to validated anxiety measures. Most patients can respond to the single-item Faces Anxiety Scale.
Objectives: To assess the validity of the Faces Anxiety Scale, the frequency and severity of state anxiety, and correlates of anxiety in intensive care patients.
Methods: A research assistant made a single clinical judgment of anxiety in the range of 1 to 10 on the basis of patients' nonverbal responses (ie, nods) to 9 questions about mood and their physical and behavioral signs. Patients then responded to the Faces Anxiety Scale. Demographic, clinical, and pharmacological data were obtained from the patients' charts.
Results: Mean age of the 106 patients was 61 years; 62% were men. Admission diagnoses were cardiovascular in 26% of patients, respiratory in 26%, trauma in 18%, neurological in 12%, gastrointestinal in 12%, and other in 6%. At the time of anxiety assessment, 89% were receiving mechanical ventilation. The correlation between patients' self-reports of anxiety on the Anxiety Faces Scale and the research assistant's assessments was 0.64 (P < .001). Some anxiety was reported by 85% of patients (mean level 2.9; SD 1.2). Anxiety levels were lower in patients who had recently received sedatives or opioids but were not related to heart rate or blood pressure.
Conclusions: The Faces Anxiety Scale is a valid means of measuring anxiety in intensive care patients. Anxiety is common in these patients and is often moderate to severe.

Critically ill patients often report that they experienced psychological distress, including anxiety and fear, during treatment in an intensive care unit (ICU). Often these reports were obtained from patients after discharge from the ICU, but increasingly investigators are seeking to learn about patients' anxiety levels during critical illness in observational studies and experimental intervention studies. To promote comfort, which is a clinically meaningful outcome in its own right, clinical practitioners seek to avert and alleviate anxiety and fear in patients during ICU treatment. In addition, evidence indicates that these emotions are associated with physiological responses, such as changes in autonomic tone, increased myocardial workload, increased coagulability, and reduced immune response, that may interfere with patients' recovery. These responses are the likely mediators of the increased morbidity and mortality that occur in more anxious critically ill patients. Thus, detection and reduction of anxiety in critically ill patients are important clinical goals for ICU staff.

Anxiety can be assessed by objective observation of physiological and behavioral signs such as heart rate, blood pressure, muscle tension, facial expression, and restlessness; by measurement of cortisol and catecholamine levels, which are increased during the stress response; or by patients' self-reports of the extent to which the patients are feeling anxious, tense, or fearful. Objective signs and biochemical measures of stress are difficult to interpret and may be unreliable in critically ill patients because the signs and values may be the result of physiological stressors, psychological stressors, or both. Therefore, research into anxiety associated with critical illness usually relies on patients' self-reports of anxiety levels. However, this approach presents other difficulties. Critically ill patients are often limited in responding to validated anxiety scales that involve cognitive effort the patients cannot sustain and verbal responses they cannot make because of tracheal intubation.

Several investigators described the use of self-reports of anxiety measures in critically ill patients. Desbiens et al used 2 simple questions about the frequency and severity of anxiety and other symptoms; the choices of answers ranged from "not at all" to "all the time" for frequency and from "not at all severe" to "extremely severe" for severity. Patients in the study were very ill and at high risk of death, but many were not interviewed about their symptoms because of intubation or other impediments to communication. Therefore, the usefulness of interviews in which those questions are used in intubated ICU patients is untested. Rincon et al used the Hospital Anxiety and Depression Scale to assess anxiety in 96 patients in critical care units in a private hospital in Central America. However, all the patients were able to communicate verbally and had low severity of illness scores and so were not representative of the general ICU population. Nelson et al used a modification of the Edmonton Symptom Assessment System, which was designed for patients receiving palliative care, to study the symptom experience of cancer patients receiving intensive care. With the modified scale, 7 symptoms, including anxiety, were assessed by using a 4-point numeric rating scale (none to severe), and 50% of patients were able to self-report. Three quarters of the patients were receiving mechanical ventilation at the time of admission to the ICU, suggesting that many intubated patients were able to respond to the anxiety numeric rating scale. However, the construct validity of analog scales has been questioned because respondents must transform subjective experience into the abstract expression of the experience represented by the scale, a task likely to be difficult for critically ill patients with limited cognitive capacity.

In 2 intervention studies with ventilator-dependent patients, the 6-item version of the Spielberger State Anxiety scale was used, the English language version in one and a Chinese language version in the other. In both studies, patients were alert and able to communicate by holding up fingers in response to questions and did not themselves complete the instruments. The internal consistency coefficient alphas were .67 and .72, which are less than the .82 reported originally for the 6-item Spielberger scale. Although this brief scale was minimally difficult for critically ill patients to respond to, Chlan remained concerned about its validity for this population and recommended further work to develop an anxiety self-report measure suitable for ICU patients receiving mechanical ventilation.

Obtaining valid and reliable measures of anxiety in ICU patients is important because of the effect of anxiety on patients' comfort and recovery. Each of the measures used in previous studies has practical or theoretical limitations for its use with ICU patients. Therefore, the Faces Anxiety Scale was developed for assessing anxiety in critically ill ICU patients, many of whom cannot respond to existing validated measures of anxiety. The Faces Anxiety Scale is a single-item scale with 5 possible responses, ranging from a neutral face to a face showing extreme fear, and is scored from 1 to 5. More ICU patients were able to respond to the Faces scale than to a 6-item anxiety scale or a numeric analog anxiety scale, and it had good properties of continuous measurement (ordinal and interval properties).

In this article, we report on the criterion validity of the Faces scale and the frequency and severity of state anxiety in a sample of ICU patients. Criterion validity requires that a scale perform well in relation to another measure that is widely used in the field and accepted as valid. For assessment of state anxiety, we would use the state anxiety component of the Spielberger State-Trait Anxiety Inventory as the criterion reference for comparison in a study population who could readily respond to the scale. However, the 20-item Spielberger State scale would not be accessible for many of the population for whom the Faces Anxiety Scale was developed. Even 6-item anxiety scales are somewhat difficult for ICU patients to complete. Therefore, in consultation with a liaison psychiatrist, we elected to use clinical judgment of patients' anxiety levels as the standard against which to assess the validity of the new scale.

The specific aims of this research were to assess the validity of the Faces Anxiety Scale in ICU patients, assess the frequency and severity of state anxiety in ICU patients, and explore correlates of anxiety in ICU patients.