ICU Psychosis

ICU Psychosis

            Some patients in the intensive care unit (ICU) experience a distorted state of consciousness. With the development of intensive care units in the early sixties came frequent reports of psychiatric symptoms (confusion, agitation, and hallucinations) in patients (Welker 2008; Ruffo et al 2002; Divitia 2006). According to Polderman and Smit (2005), ICU psychosis is frequently occurring yet it is often under-diagnosed and under-treated. Within ICUs, the term ‘ICU psychosis’ has been used to describe hallucinations, delusions and  fluctuating level of consciousness, poor orientation, passivity or aggression (Pierce et al 2004)Among the common symptoms of psychosis are hallucinations and delusions. Hallucination happens when a person hear, feel, see or smell something that is not real. Delusion on the other hand, happens when a person have unusual beliefs that are not shared by other people (NHS Direct 2008). These psychiatric symptoms are often called syndromes. These syndromes have been given different names – post-surgery psychiatric syndrome, ICU confusion or psychosis, post-operative delirium, post-operative encephalopathy, and delirium. The estimates prevalence of acute confusion in hospitalized patients has ranged from 5 to 70 percent, depending on the population studied and criteria used for diagnosis. The occurrence of acute confusion is highest in elderly patients hospitalized for any reason and in patients following cardiac surgery (Neelon 1990 cited in Lawrence 1997).

            It has been shown that acute confusion or delirium, especially in elderly patients increases length of hospital stay as well as mortality (Axell et al 2002). According to Immers et al (2005), ICU psychosis is a serious, high-frequency complication in intensive care unit patients. The consequences of this complication range from high morbidity to mortality to greater need for nursing care.

 

            In 1988, Easton and MacKenzie conducted an investigation of ICU psychosis. According to them, ICU psychosis is a reversible, confusional state that usually occurs between the third and seventh day on an ICU and generally disappears within 48 hours after discharge. They report that 12.5 to 38 percent of conscious patients experience this phenomenon. In their own sample of patients, 50 percent or 5 patients, recalled that they thought they were going crazy. They responded hesitantly for fear of being labeled mentally ill and they thought they were the only ones to experience this problem. The patients reported 27 delirious experiences, of which only one was pleasant – most were scary, terrifying, or very frightening (cited in Olevitch 2002).

 

            The highest incidence of ICU psychosis has been reported in the surgical intensive care unit (SICU), followed by the medical intensive care unit (MICU), and the coronary care unit (CCU) and general medical and surgical wards respectively” (Easton and MacKenzie 1988).

 

            These patients’ experiences tend to be frightening for the subjects and have a general paranoid quality to them. Very common is a feeling of being held captive and being part of an experiment. One study described the illusions of a 56-year-old housewife admitted because of aortic stenosis, secondary to rheumatic heart disease (Abram 1965). Six days after surgery to replace her aortic valve she experienced a psychotic episode. The following are the words of a nurse describing her behavior. “Patient is evidently experiencing auditory hallucinations – says she hears her daughter’s husband paged over the p.a. system, has been smelling strange gas all day.” When the patient was seen by a psychiatrist, she told him she was convinced she would be taken back to the operating room for more surgery. In addition, she thought the “new machines” had been brought to her room to do her harm (Abram 1965, pp. 662-663). Another study of open-heart surgery patients found that eight out of twelve subjects had a major psychotic episode (Blacher, 1972). Five had delusions or hallucinations and three loss of memory and confusion.

 

Predisposing Psychological Factors

            Most of the psychiatrists who have conducted investigations in this area have advocated explanations that include the severe anxiety experienced by the subjects. All their subjects came close to dying or at least had some risk of dying. If the threat of death was overwhelming, the psychiatrists believed it could contribute to hallucinations and illusionary experiences.

            Psychiatric history and personality type are also believed to be contributing factors. Individuals with preoperative psychiatric illnesses have been found to be more prone to development of delirium when hospitalized with a serious illness (Dubin and Field 1979). Individuals with dominant, aggressive, and self-assured personalities were found to be the most likely to be affected by delirium (Kornfeld 1978 cited in Lawrence 1997). The predisposing psychological factors for ICU psychosis are:

 

1. Deprivation

            Several studies have been done on the hallucinations that occur when subjects experience either sleep or sensory deprivation (Helton 1980; Comer 1967). Since sleep and sensory deprivation are common in ICUs many believe they can be contributing causal factors.

2. Biophysiological Factors

            Individuals who have been addicted to drugs or alcohol have a predisposition to hallucinations, illusions, and delusions when seriously ill. Since many admisions to ICUs are occasioned by accidents where drugs and/or alcohol have been involved, it is not unusual for drug and alcohol users to go through withdrawal while in the ICU. Patients with chronic cardiovascular, metabolic, or respiratory illness are at a higher risk for developing delirium while in the ICU. Physiologic aberrations caused by hemorrhage, septic shock, anoxia, acid-base imbalance, and other serious physiological changes have been documented in persons with ICU psychosis (Lawrence 1997).

3. Pharmacological Agents

            Fifteen common pharmacologic agents used in ICUs include acute delirium, hallucinations, agitation, paranoia, confusion, or nightmares as potential side effects (Easton and MacKenzie 1988). With so many potential causes, it is difficult to establish the necessary and sufficient conditions for a psychotic episode to occur in a serious illness. Since these episodes are transitory, emphasis has been on identifying patients at risk and supporting the patient after the experience.

 

Pathophysiological Causes

            ICU psychosis of post-operative delirium affects about 20 percent of the patients undergoing cardiac surgery, the estimates ranging from 3 percent to 47 percent. It has been associated with several pre-operative risk factors.

 

Among the most common factors in developing ICU psychosis are:

• Metabolic disturbances


• Electrolyte imbalances


• Withdrawal syndromes


• Acute infections


• Seizures


• Head trauma


• Vascular disorders


• Intracranial space-occupying lesions (McGuire et al 2000)

 

            The exact pathophysiological causes of ICU psychosis are unknown. However, it is believed that one of the pathophysiological causes is the imbalances in the neurotransmitters that modulate the control of cognitive function, behavior, and mood (Truman and Ely 2003).

 

            Abnormalities of various neurotransmitter systems as a consequence of decreased oxidative metabolism in the brain have been implicated in the pathophysiology of delirium. According to this neurotransmitter hypothesis, delirium may be the result of reduced cholinergic function, excess release of dopamine, norepinephrine, and glutamate, and both decreased and increased serotonergic and gamma-aminobutyric acid activity (Van der Mast et al 2000).

 

            Changes in the levels of various amino acids that are precursors of cerebral neurotransmitters may affect their function and thus lead to delirium. For example, the production rate of brain serotonin (5-hydroxytryptamine or 5-HT) is dependent on the plasma availability of its precursor tryptophan (Trp). Trp competes with the other large neutral amino acids (oLNAA), such as tyrosine (Tyr), phenylalanine (Phe), valine (Val), leucine (Leu), and isoleucine (Ile), for transport across the blood-brain barrier (BBB). The ratio of Trp to the oLNAA eventually determines the amount of Trp that reaches the brain and consequently the synthesis of cerebral 5-HT. Thus, delirium after cardiac surgery has been associated with reduced plasma tryptophan and, consequently, decreased cerebral 5-HT function. Furthermore, phenylalanine is a precursor of dopamine and norepinephrine through a Tyr connection. The ratios of Tyr and Phe to the oLNAA determine the amount of Tyr and Phe that enter the brain. An increase in the cerebral uptake of Tyr and Phe may be a risk factor for the development of delirium if excess release of dopamine and norepinephrine is implicated in its Pathophysiology (Van der Mast et al 2000).

 

            Surgical trauma induces physical stress, increased activity of the limbic-hypothalamic-pituitary-adrenal axis, and a low triiodothyronine (T3) syndrome. The latter is characterized by a decreased level of active T3 as well as an increased level of inactive reverse T3, in the absence of thyroid illness. The degree of thyroid hormone alterations is dependent on the severity of disease or trauma, and it is both a measure of physical condition and a predictor of prognosis.  A low-T3 syndrome very likely causes a generally decreased metabolism through reduced synthesis of adenosine triphosphate (ATP). This is another mechanism by which the production of 5-HT in the brain may be endangered, since Trp hydroxylase needs tetrahydrobiopterin as a cofactor, and the latter may be reduced in the presence of decreased ATP. Thus, surgery itself may contribute to an imbalance of neurotransmitters. Surgery also causes an increase in corticosteroid levels. Cortisol is an important stress hormone that has modulating effects on both the limbic system and the immune system and that inhibits the release of thyroidstimulating hormone (TSH). Thus, changes in cortisol may influence brain function, immune function, and thyroid function and, through interacting mechanisms, may provoke delirium. Surgery may endanger the transport of Trp across the BBB, because the plasma concentrations of the oLNAA may be increased via degradation of muscle proteins, and second because elevation of corticosteroid levels induces Trp pyrrolase in the liver, reducing plasma Trp availability for the brain (Van der Mast et al 2000).

 

Clinical Practices that Increases the Risk of ICU Psychosis

Drug Therapy

            Drug therapy is seen as a contributing factor to the development of delirium. If a medication is not stopped promptly, it can contribute to the occurrence of delirium. Drugs that exhibit antimuscarinic or domaninergic activity are particularly associated with the development of delirium. Increased plasma concentrations and/or increase blood brain barrier permeability may make patients particularly prone to the deliriogenic effects of some drugs. Certain drugs can contribute to the development of delirium. These drugs are:

• Analgesics


• Anti-depressants


• Anti-convulsants


• Anti-histamines


• Anti-emitics


• Anti-psychotics


• Anti-muscarinics


• Cardiovascular Agents


• Corticosteroids


• Hypnotic Agents

 

 

The Role of the Nurse in Preventing ICU Psychosis

            Nurses are responsible for providing early detection and coordinating with other health professionals in initiating a plan of care for the patient. The nurses need to promptly treat delirium to reduce the signs and symptoms, duration and potential adverse sequel of the disorder (Justic 2000). Nurses, who spend more time at the bedside than physicians, play a crucial role in the recognition of delirium. Because nurses have frequent and continuous contact with patients, they can better observe fluctuations in attention, level of consciousness, and cognitive functioning. As a result, the observations made by nurses are critical for the early detection of delirium symptoms and for the continuous monitoring of these symptoms that is essential to follow the patient’s clinical course.12 With training and supervision, delirium symptoms can be monitored effectively by nurses (Inouye et al 2001).

 

I. Non-Pharmacological Interventions (Borthwick et al 2006)

1. The nurse must provide support and orientation to the patient. The nurse must:

• Communicate clearly and concisely; give repeated verbal reminders of the day, time, location, and identify key individuals, such as members of the multidisciplinary team and relatives.


• Provide clear signposts to patient’s location including a clock, calendar, and chart with the day’s schedule.


• Have familiar objects from the patient’s home in the room preferably by the bed.


• Attempt consistency in nursing staff.


• Use television or radio for relaxation and to help the patient maintain contact with the outside world. Some discretion is required as patients may build events from television programs or radio into delusions.


• Involve family and caregivers to encourage feelings of security and orientation.

2. The nurse must make sure to provide an unambiguous environment

• Attempt to create a day/night cycle with lights off at night but on all day with appropriate day time stimulation.


• Control sources of excess noise.


• Keep room temperature between 21.1 °C to 23.8 °C

3. The nurse must maintain the competence of the patient

• Identify and correct sensory impairments.


• Encourage self-care and participation in treatment.


• Arrange treatments to allow maximum periods of uninterrupted sleep.


• Maintain activity level.

 

 

 

References

 

Abram H. S. (1965). Adaptation to Open-Heart Surgery. American Journal of  Psychiatry, 122, 659-667.

 

Blacher R. (1972). The Hidden Psychosis of Open-Heart Surgery. JAMA, 222(3), 305-308

 

Borthwick, M., Bourne, R., Craig, M., Egan, A. and Oxley, J. (2006). Detection, Prevention and Treatment of Delirium in Critically III Patients. United Kingdom Clinical Pharmacy Association.

 

Comer N., Madow, L. and Dixon, J. (1967). Observations of Sensory Deprivation in a Life-Threatening Situation. American Journal of Psychiatry, 124( 2), 164-169.

 

Divatia, J. V. (2006). Delirium in the ICU. Indian Journal Of Critical Care Medicine, 10(4):215-218.

 

Dubin W. R., Field, H. L. and Gasfriend, B. S. (1979). Postcardiotomy Delirium: A Critical Review. Journal of Thoracic and Cardiovascular  Surgery, 77, 586-594.

 

Easton, C. and MacKenzie, F. (1988). Sensory-Perceptual Alterations: Delirium in the Intensive Care Unit. Heart and Lung, 17, 229-235.

 

Helton M. C., Gordon, S. H. and Nunnery, S. L. (1980). The Correlation Between Sleep Deprivation and the Intensive Care Unit Psychosis. Heart and Lung, 13, 59-65.

 

ICU Psychosis (2008). Medicine Net. Retrieved September 17, 2008, from http://www.medicinenet.com/icu_psychosis/article.htm

 

Immers, H., Schuurmans, M. J. and Van de Bijl, J. (2005). Recognition of delirium in ICU patients: a diagnostic study of the NEECHAM confusion scale in ICU patients. BMC Nursing, 4(7).

 

Inouye, S. K., Foreman, M. D., Mion, L. C., Katz, K. H., Cooney, Jr, L. M. (2001). Nurses’ Recognition of Delirium and Its Symptoms – Comparison of Nurse and Researcher Ratings. Archives of Internal Medicine , 161:2467-2473.

 

 

Justic M. (2000). Does “ICU psychosis” really exist? Crit Care Nurse. 20:28-37

 

Kornfeld D. S., et al. (1978). Delirium After Coronary Artery Bypass Surgery. Journal of Thoracic and Cardiovascular Surgery, 76, 93-96.

 

Lawrence, M. (1997). In a World of Their Own: Experiencing Unconsciousness. Westport CT: Bergin and Garvey.

 

McGuire, B., Basten, J., Ryan, C., and Gallagher, J. (2000). Intensive Care Unit Syndrome: A Dangerous Misnomer. Arch Intern Med. 160, 1-4.

 

Olevitch, B. A. (2002). Protecting Psychiatric Patients and Others from the Assisted-Suicide Movement: Insights and Strategies. Westport CT: Praeger.

 

Pierce, J. M. T., Allenby-Smith, O. and Goddard, J. (2004). Delusional memories following cardiac surgery and prolonged intensive care: a retrospective survey and case note review. The British Journal of Cardiology, 17(11): 262-266.

 

Polderman, K. H. and Smit, E. (2005). Dealing with the delirium dilemma. Crit Care, 9(4):335-336.

 

Psychosis (2008). NHS Direct. Retrieved September 17, 2008, from http://www.nhsdirect.nhs.uk/articles/article.aspx?articleId=303

 

Ruffo, D., Osbourne, J., Peters, M., Johnston, J. Stuart, M., Christopher, J. M., Chan, G. and Wen, E. (2002). Post-Operative Delirium: A Predictive Tool. Geriatrics Today, 5:21-24.

 

Truman, B. and Ely, W. E. (2003). ‘Monitoring Delirium in Critically Ill Patients: Using the Confusion Assessment Method for the Intensive Care Unit’ Critical Care Nurse, 23(2), 25-35.

 

van der Mast, R., et al. (2000). Is Delirium After Cardiac Surgery Related to Plasma Amino Acids and Physical Condition. Neuropychiatry Clin Nuerosci Journal. 12(1), 57-63.

 

 

 

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