Understanding and managing anxiety sensitivity during critical illness and long-term recovery

Abstract

Anxiety sensitivity is a fear of symptoms associated with experiencing anxiety (e.g., rapid respiration/heart rate, perspiration) also known as “Fear of Fear”. These fears are a misinterpretation of non-threatening symptoms as threatening across three domains: physical (“when my heart rate increases, I’m afraid I may have a heart attack”), social (“if people see me perspire, I fear they will negatively evaluate me”), and loss of control (“when I feel these symptoms, I fear it means I’m going crazy or will lose control and do something dangerous like disconnect my IV”). These thoughts stimulate the sympathetic nervous system resulting in stronger sensations and further catastrophic misinterpretations spiraling, at times, into a panic attack. Strategies to address anxiety sensitivity may include pharmacologic or non-pharmacologic interventions. In Intensive Care Unit (ICU) settings, anxiety sensitivity is relevant to physical, social, and loss of control spanning common monitoring and interventional procedures (e.g., oxygen therapy, repositioning, urine collection systems). Furthermore, anxiety sensitivity could be a barrier to mechanical ventilator weaning strategies when patients are uncomfortable following instructions to do awakening or breathing trials. Fortunately, anxiety sensitivity is a malleable trait with evidence-based intervention options. However, few healthcare providers are aware of this psychological construct and available treatment. This paper describes the nature of anxiety sensitivity, its potential impact on ICU care, how to assess and interpret scores from validated instruments (i.e., Anxiety Sensitivity Index), and treatment approaches across the critical care trajectory inclusive of post-ICU recovery. Implications and future directions are also discussed.

Introduction

Anxiety sensitivity (AS) is the fear of experiencing anxiety-related symptoms and its associated sensations.^1,2 Conceptually, AS is the intolerance or catastrophic appraisal of anxiety-related sensations that then serve to exacerbate these sensations and, in turn, leads to maladaptive escape and avoidance behaviors.² As such, AS has shown to be an essential factor in terms of behavioral considerations and the experience of psychological distress. Once AS develops, the fears may influence health behaviors, resulting in avoidance of healthy behaviors, medication nonadherence, and engagement in maladaptive behaviors.^3,4

AS is a significant predictor of psychopathology and maladaptive behaviors.² Meta-analyses have demonstrated strong support for the relationship between anxiety-related disorders and AS, particularly posttraumatic stress disorder (PTSD), panic disorder, and suicidal ideation.^5,6 AS has also been linked to chronic illness (e.g., asthma, cardiovascular disease, chronic pain), and problematic health behaviors (e.g., non-medical benzodiazepine use, tobacco use, lower exercise engagement, medication nonadherence).^2,4,7–10 Not only do these consequences cause distress and impairment in those with AS, they also increase the burden on the healthcare system. As such, AS is associated with increased healthcare utilization and emergency room visits.¹¹ Because AS is associated with a number of negative individual and organizational outcomes, it is considered an important psychological/behavioral condition shared across different types of health disorders (i.e., transdiagnostic factor).

AS is applicable to acute and critical illness when unpleasant sensations such as pain, shortness of breath, nausea, and thirst are experienced. While the role of AS has been examined less in individuals with critical illness, it is possible that higher AS may lead to avoidance of activities perceived to increase feared sensations and thus increase patient avoidance, affecting the delivery of critical care interventions (e.g., physical/occupational therapy, repositioning, sedative/ventilator weaning). After critical illness, this could result in disengaging with follow-up services due to fear of revisiting distressing feelings associated with the ICU admission, not participating in physical therapy due to fear of pain, or not reporting post-intensive care syndrome (PICS) symptoms (e.g., anxiety, depression, PTSD) for fear of being negatively perceived by others.

It is important for ICU providers to consider strategies to assess what may be a “true alarm” or sensations that require medical intervention versus a “false alarm” or anxiety symptoms that require a psychological intervention. For instance, patients having difficulty weaning from mechanical ventilation should undergo detailed work up for underlying medical causes (e.g., upper airway resistance, cardiac dysfunction, diaphragmatic insufficiency), prior to assessing AS for the primary cause. Moreover, fear and anxiety are a common result of ICU delirium and should be ruled out or managed prior to assessment and treatment for anxiety sensitivity, as delirium precludes proper understanding of circumstances and learning new information. This review explores the concept of AS across the trajectory of critical care, proposes a role for ICU providers in the identification and management of AS by using strategies to engage patients and care partners, and introduces future directions for critical care research.

Overview of Anxiety Sensitivity

AS is described as the fear of anxiety symptoms and beliefs about the harmfulness of anxiety symptoms.¹² Just as individual responses to experiencing anxiety vary (e.g., becoming anxious with minimal provocation vs. only under the most stressful circumstances), differences in responses to AS can vary. An individual’s AS plays a key role in the maintenance of anxiety-related disorders (e.g., panic disorder, social anxiety disorder) and avoidance behaviors (e.g., substance abuse, social withdrawal, declining medical interventions). Meta-analytic reviews have established strong associations between AS and anxiety-related disorders, with particularly strong associations between AS, panic disorder, and PTSD.^5,13 The domains of AS (i.e., physical, social, and cognitive concerns) are also differentially associated with anxiety-related disorders. For example, the physical concern dimension of AS is associated with panic disorder and health anxiety, while the cognitive concern dimension has been found to be greater among those with comorbid PTSD and generalized anxiety disorder.^14,15

In the Zvolensky framework,² AS serves as an intensifying factor in interpreting physiological responses (e.g., increased heart rate, tachypnea) in combination with cognitive catastrophizing (e.g., this must mean I am having a heart attack), which lead to exacerbation of anxiety and panic. Research examining the assessment and treatment of AS is expanding to advance the implications of assessing and addressing AS in the context of anxiety and high distress situations.

Identifying Anxiety Sensitivity

Anxiety sensitivity is most often measured using the validated Anxiety Sensitivity Index (ASI) and, most recently, the ASI-3.^1,16 The ASI-3 is an 18-item scale measuring physical, cognitive, and social concerns individuals may have regarding their anxiety. Each item is scored from ‘very little’ to ‘very much’. Higher scores indicate greater AS, with a score ≤18 indicating very little fear of anxiety-related sensations. Below are ASI-3 statements with related thought and behavior pattern examples.

• Physical concern: It scares me when my heart beats rapidly. Example: ‘I’m having a heart attack.’

• Cognitive concern: It scares me when I am unable to keep my mind on a task. Example: ‘I’m afraid I will forget what I am doing and fall, so I tell the physical therapist I don’t want to stand.’

• Social concern: I worry that other people will notice my anxiety. Example: ‘When I get scared and short of breath, I’m afraid people are going to notice and not take my medical problem seriously.’

During critical illness hospitalization, observable signs of AS may include asynchrony with the ventilator, tachypnea, tachycardia, or expressions of anxiety or agitation in the absence of physiologic explanations. Patients may also require significant staff time. Similarly, during long-term recovery from critical illness, patients with AS may need increased assessment time, extra explanation and demonstration prior to participation in physical therapy, and reassurance of safety when experiencing physical discomfort. When asked about fears during the phase after critical illness, a patient may be afraid of a heart attack or inability to breathe, people noticing or evaluating them negatively (particularly related to previously independent activities like toileting), losing control or one’s mind (especially those who experienced delirium), becoming a burden on family members, an inability to work, or dying alone.

Factors Contributing to Anxiety Sensitivity

Four concepts underpin the etiology of AS. First, genetics may contribute to AS with a heritability estimate of 45%.^17,18 Second, parenting responses to childhood illness/injury may reinforce attending to and misinterpreting anxiety symptoms.¹⁹ Third, a history of unexpected panic attacks increases the likelihood of AS.^20,21 Finally, stressful life events are associated with AS.^18,22

Critical Illness and Anxiety Sensitivity

Anxiety and fear co-occur frequently during critical illness when patients experience a heightened volume and intensity of physiological cues and other stressors. Nearly 50% of ICU patients experience clinically significant anxiety symptoms during their ICU stay.²³ Common stressors during critical illness and hospitalization can include loss of control and independence, pain, delirium, sensory deprivation, social isolation, and/or imminent death. Challenging physiological symptoms such as breathlessness, fatigue, procedural and positional pain, dizziness associated with hypotension may be viewed by patients as deadly, rather than a strange but expected component of recovery. Invasive medical procedures such as mechanical ventilation, indwelling urinary catheters, chest tubes, intravenous lines, and other tethers can be significant potential triggers for anxiety, and thus amplified with AS. Finally, several medications important in critical care (e.g., steroids, vasopressors) may be associated with increased anxiety and agitation.²⁴ The critical care setting is a particularly stimulating environment for patients with pre-morbid AS to have these symptoms greatly exacerbated.^25,266

Critical illness is a commonly fear-inducing experience. Critically ill patients are experiencing one, if not multiple, complex acute and chronic health conditions requiring close monitoring of physiological changes (e.g., organ failure, diabetes, heart disease), medication management, and diet. Patients may also associate physiological changes to past experiences requiring hospitalization, for instance, an increased heart rate right before an internal defibrillator shock. This can lead to associating heart rate changes to intense fear that another shock will occur and, thus, avoiding behaviors resulting in heart rate changes. In a study of COPD patients, after accounting for depression and anxiety, AS-physical symptoms significantly predicted increased COPD symptom exacerbations, increased emergency room visits, and hospitalizations.²⁷

Likewise, after hospitalization, ICU survivors often struggle with anxiety and PTSD.²⁸ Some patients report not wanting to leave the hospital for fear of getting sick again, and others describe not attending important medical care to avoid reminders of hospitalization. The physical distress, loss of control, and disorientation associated with critical illness can manifest as long-term physical and psychological trauma and vulnerability. Stressors in the form of new or worsening chronic conditions occurring during long-term ICU recovery may include physical deconditioning, cognitive impairment, depression, medication access challenges, increased healthcare utilization, and use of durable medical equipment²⁹. Potential anxiety sensitivity triggers may include sounds (e.g., microwave timers sound like ventilator alarms), nightmares, changes in voice or swallowing due to laryngeal injuries from endotracheal intubation, or the need for mobility aids (e.g., cane, walker) to resume walking. ICU survivorship often involves psychological, cognitive, and physical difficulties as patients and care partners navigate the implications of recovery and adaptations in resuming pre-critical illness activities and routines.^30,31

Traditional Approaches to Managing Anxiety Sensitivity

AS has not only been found to be an integral aspect of many anxiety and mood related disorders, but specifically a strong mediator and mechanism of change in treatment outcomes, indicating that AS should be considered as a treatment target.^32,33 AS has shown to be effectively improved in tandem with treatment for a diagnosed mental health disorder, such as in cognitive behavioral therapy (CBT) for panic disorder.^34,35 Due to the prevalence of AS across mental health disorders, treatments targeting AS are widely applicable to treatments for multiple mental health concerns (e.g. depression, PTSD, panic disorder).

Brief formatted treatments for individuals with high AS at risk for the development of psychopathology, have promising results.^31,34,36 AS-specific treatment drawn from traditional CBT therapies includes psychoeducation, cognitive restructuring, interoceptive exposure, and situation exposure.^35,37 The Unified Protocol for emotional disorders has also been used to treat AS, with interoceptive exposure highlighted as the most effective component.³⁸ Psychoeducation targets normalizing anxiety and its related sensations, while interoceptive exposure intentionally induces anxiety-related sensations to demonstrate that experiencing these sensations will not lead to catastrophic outcomes.³⁹ Cognitive bias modification is an intervention that prompts individuals to focus on positive information and experiences rather than negative experiences that give rise to AS. Treatment for AS in an ICU setting (e.g., psychological first aid) is different from traditional outpatient settings for formal psychiatric diagnosis (e.g., cognitive behavioral therapy for panic disorder). While traditional cognitive behavioral therapies often include 8–12 sessions, brief treatment for AS may be implemented in as little as 1 session.³⁶ Treatments for AS have shown efficacy in reducing not only AS, but also alcohol and opioid use, anxiety and depressive symptoms, smoking cessation, and suicidal ideation.^37,40–43 Assessment tools like the ASI-3 can identify the primary domain of AS distress (i.e., physical, social, cognitive) to tailor treatment.

Implications for Critical Care Practice

While the assessment and management of anxiety in the trajectory of critical illness is well-established,²⁶ the state of the science specific to AS is limited. Research is needed to inform clinical implications and interventions during and after critical illness. Patients with AS may experience increased distress when undergoing medical interventions, such as mechanical ventilation or invasive procedures, thus triggering fears of experiencing the physical symptoms of anxiety. As such, ICU providers should be aware of AS to employ clear communication, pain management, and/or relaxation techniques to mitigate distress and improve patient outcomes.

Managing Anxiety Sensitivity in the Inpatient Setting

To differentiate between AS and other medical situations, a thorough medical evaluation is typically necessary. AS can coexist with other medical conditions, and in some cases, the physical symptoms may be caused or exacerbated by anxiety. Therefore, a comprehensive evaluation considering both physical and psychological factors is often necessary to accurately manage a patient’s symptoms. However, communication barriers due to mechanical ventilation and delirium can inhibit validated assessment of AS during critical illness. Thus, management largely relies on reducing stressors through environmental modification to minimize AS triggers.

Providing basic psychoeducation about common physiological and psychological symptoms in ICU patients may provide a buffer for tempering AS. For example, “it’s normal to feel scared when you are short of breath. You are getting better, so this shortness of breath is typical and uncomfortable, but not deadly.”⁴⁴ It can also help to provide education about ICU delirium, the process of resolution, and reassurance that this is not a new, permanent psychiatric condition. Helping patients identify aspects of recovery within their control may reduce anxiety and increase engagement during critical illness (e.g., physical therapy timing, type of music, communication tools).

Nurse-Led Strategies during Critical Illness

Some evidence-based strategies for reducing stressors and minimizing AS triggers include family visitation and involvement to reduce social isolation, adjusting sensory stimuli to promote a comfortable and calming environment (e.g., reduce noise levels), promoting sleep-wake balance, fostering clear and timely communication, and music therapy.^45,46 When a patient is experiencing an AS crisis in need of more urgent intervention, psychological first aid can be provided (Table 1). Psychological first aid helps the patient to feel safe, connected, and supported by providing practical and emotional support.⁴⁷ Psychological first aid may include assuring the patient of their safety, listening actively to concerns, using calming techniques (e.g., hand holding, breathing techniques), or providing distraction. For example, if a patient is hyperventilating, suggest they close their mouth as it is very difficult to hyperventilate with a closed mouth. If time permits, instruction to patients for paced breathing (e.g., inhale 2–3, exhale 2-3-4-5) for a 3-minute period can be employed. These activities can provide the patient with an added sense of control.

Table 1.

Anxiety Sensitivity Crisis Interventions

Activation Criteria	Intervention
Hyperarousal (e.g., tachycardia, diaphoresis, restlessness)	Verbal reassurance of safety Assessment of family/visitor involvement (presence or absence) Medication management (e.g., anxiolytics, antidepressants) Nurse presence to provide a calm presence Assessment and changes to reduce external stimuli (e.g., lighting, visitors) Use short, simple directions Provide reassurance of physiological status Avoid asking the patient to make decisions
Hyperventilation when not mechanically ventilated	Coach patient to close their mouth to inhale and exhale from their nose Coach patient through paced breathing counts (inhale 3 seconds and exhale 5 seconds) for 3 minutes with instructions for the patient to self-pace and continue the exercise Medication management (e.g., sedatives, anxiolytics, antidepressants)
Panic during mobilization	Adequate pain management Coaching and reassurance during physical therapy Break mobility activities into small steps (e.g., step 1 for walking is to push off with walker, now shift your weight to the front leg, next bring your back foot forward, etc.)

Family Engagement Strategies during Critical Illness

Family engagement for managing AS requires awareness of AS, its triggers, and how to recognize and manage patient symptoms. Family members can be engaged to identify root issues with the patient (e.g., tubes, lines, loss of control, previously feared triggers) and provide information on ICU treatments/equipment to facilitate a sense of control for the patient. Family members can provide important information about what helps the patient feel safe and relaxed in their day-to-day life (e.g., music preferences, relaxing touch, pleasurable activities). By extension, family may be encouraged to bring in comforting or familiar objects from home. Those who are comfortable and interested can also take an active role in patient care by helping with basic activities of daily living (e.g., grooming) and physical therapy (e.g., range of motion exercises) which may facilitate a sense of patient comfort and familiarity.^48,49 Family members can also work with ICU providers and patients to set goals for ICU treatment and recovery to ensure collaborative decision making and patient empowerment.

Managing Anxiety Sensitivity during Critical Illness Recovery

Psychological first aid offered during inpatient hospitalization is not a long-term solution for AS. Patients may become fearful the breathing exercises practiced during hospitalization will not work after hospital discharge. Following robust physical assessments, to rule out any ongoing physiological issues, ICU Recovery Clinics and peer support programs could incorporate AS assessment and management for overall wellbeing. Within the multidisciplinary ICU Recovery Clinic or peer support setting, psychoeducation can be provided about the nature and causes of anxiety and panic. Psychologists and/or social workers embedded within ICU recovery programs can describe how the sympathetic nervous system is triggered causing changes to happen in the body for the purpose of protecting, keeping safe, and avoiding danger. This sympathetic response is meant to feel uncomfortable for the purpose of motivating, akin to a fire alarm, which is safe when it goes off, but alerts you to leave the building. Content areas for psychoeducation materials are described in Table 2. Given anxiety was one of the few objective constructs which did not improve in recent research which examined the effectiveness of a complex intervention for ICU survivors,⁵⁰ the integration of AS assessment and management may prove incredibly important for future practice in this area.

Table 2.

Content for Anxiety Sensitivity Psychoeducational Materials

Domain	Educational Content
Definition	Fear of anxiety-related sensations or symptoms; a belief that these sensations are dangerous, and their presence indicates something harmful is happening
Physiology	Description of sympathetic nervous system response
Causes	Genetics, early life experiences, exposure to trauma or stressful life events Common feature of anxiety disorders (e.g., panic disorder, social anxiety disorder, generalized anxiety disorder)
Effect on daily life	Avoidance of situations that trigger symptoms Interferes with social, occupational, academic functioning Contributes to development of anxiety disorders
Treatment options	Descriptions of Psychological first aid Cognitive behavior therapy (e.g., cognitive restructuring, exposure) Psychotherapy Mindfulness practices Medication
Coping strategies	Relaxation exercises, meditation, physical activity, social support
Lifestyle changes	Avoiding caffeine, alcohol, and nicotine
Self-care	Encourage hobbies, creative outlets, self-compassion
Support resources	Mental health professionals, support groups, online resources

Interceptive exposure is a cognitive behavioral therapy technique for therapeutically exposing someone to bodily sensations that are associated with AS triggers in a controlled and gradual manner to reduce fear and anxiety.³⁹ Through this exposure, the patient can better identify the difference between true and false alarms (e.g., knowing the difference between when to go to the hospital versus when the symptoms are anxiety). For each AS sensation, there are different exposures that can be simulated (e.g., hyperventilation, tachycardia), when not contraindicated, to trigger AS and perform in-the-moment cognitive modification (Table 3). The brain knows this is anxiety, but the limbic system does not. Through the interceptive exposure process, it can be acknowledged that the amygdala set off an alarm, but also acknowledged that the patient is 1) afraid of having a heart attack, 2) not having a heart attack, and 3) not dead.

Table 3.

Cognitive Modification Exemplars

Situation	Sensation	Thought/Stuck Point	Thought Challenge	Alternative Thought
Physical Therapy	Lightheaded/ Short of Breath	I’ll pass out, fall, and seriously injure myself. Feels 80% likely.	How many times have you felt lightheaded or short of breath? How many times when you felt this way did you fall and seriously injure yourself? What is the likelihood of getting hurt during physical therapy from 0 (none) to 100 (absolute)?	I’m safe. My brain is setting off an alarm. This isn’t comfortable, but also not harmful. The doctors have told me it is anxiety from hyperventilation, and this actually makes it less likely I will pass out. My physical therapist can help me.
Walking to the bathroom	Heart racing	I’ll have a heart attack. Feels 70% likely.	How many times have you noticed your heart racing? How many times when you felt this way have you had a heart attack? What are some other reasons for your heart to be racing?	There are several reasons for my heart to be racing. The doctors said I do not have a heart condition. It is likely caused from activity, the coffee I had this morning, or anxiety. This does not mean I am having a heart attack. I will take a few deep breaths before deciding if I should call a doctor.

Research and Practice Priorities for Anxiety Sensitivity and Critical Illness

There are several AS critical care research needs across inpatient and outpatient settings, including measurement and intervention development. Population-level incidence and prevalence reports are needed to interpret the significance of AS in the critical illness trajectory. Risk factors for AS may include the types of invasive tubes and lines, sleep disruption, acute illness characteristics, and ongoing biological mechanisms such as hyperinflammation. Education and dissemination are fundamental to increasing provider awareness and assessment of AS during and after critical illness. For example, AS assessment measures could be piloted for validity and acceptability with ICU patients and survivors in partnership with qualitative description of the patient experience of AS and what helps to reduce symptoms. Protocolized intervention methods are needed to establish cause-and-effect relationships for patient-centered AS management, with corresponding feasibility studies to assess implementability, safety, and efficacy. Longitudinal studies examining interventions are warranted to evaluate short- and long-term efficacy. Addressing AS research priorities could improve quality and outcomes for individuals with AS during and after critical illness.

Conclusion

Understanding the prevalence and characteristics of AS in ICU survivors is crucial. A ‘fear of fears’ can amplify anxiety surrounding all stages of the critical illness trajectory, from ICU admission through long-term recovery. Detection and interventions in the inpatient and outpatient settings are relevant to critical care. Future research should examine the integration of AS assessment and management techniques across the critical care recovery continuum.