MD-MOSAIC: A Proposed Psychiatrist’s Guide for Assessment of Altered Mental Status in Mechanically Ventilated Patients With Critical Illness

Altered mental status (AMS) is a frequent concern in patients with critical illness, necessitating a thorough evaluation and diagnostic studies to promptly identify and address potentially reversible underlying causes. Delirium is the most common cause of AMS in the intensive care unit (ICU), and its early recognition and treatment can help prevent numerous adverse downstream effects.¹ In the United States, more than 7 million hospitalized patients face delirium each year,² with the highest incidence of delirium seen in patients who require intensive care. Delirium represents a final common pathway of physiologic, pharmacologic, and iatrogenic causes, and a patient’s risk of becoming delirious while hospitalized is proportional to the severity of their underlying conditions and to the acuity of their presenting illness.³ In a previous study, delirium occurred in 20% to 50% of nonmechanically ventilated patients in the ICU and 60% to 80% of mechanically ventilated patients.⁴ Unfortunately, patients with delirium face higher ICU (20% vs 10%) and in-hospital (31% vs 24%) mortality rates.⁵ Additionally, ICU patients with delirium face cumulative risks with each day they remain delirious, which include a 20% increase in the risk of a patient remaining in the hospital per day and 10% increase in mortality risk.⁶

The incidence of delirium is expected to rise as the United States population ages and as predisposing conditions including major neurocognitive disorder (formerly dementia) and polypharmacy become more widespread. By 2030, all baby boomers will be older than 65, and they will make up 20% of the US population.⁷ From 2012 to 2050, the number of individuals older than 65 is anticipated to increase from approximately 43.1 million to 83.7 million in the US.⁸

Given the high prevalence of delirium across clinical specialties, it is crucial to prioritize strategies for delirium prevention, assessment, and management in the training of all physicians, especially psychiatrists. With the specific challenges and communication barriers that can accompany critical illness, special considerations for patients with critical illness, AMS, and other neuropsychiatric symptoms apply. This can be seen in the guidelines for critical care medicine training and continuing medical education, which were developed by the American College of Critical Care Medicine and include Category D-3: Psychiatric emergencies and Category I-1: Drug overdose and withdrawal.⁹

Multiple Domain Mental and Orientation Status Assessment for Intensive Care

Here, we propose a novel framework known as the Multiple Domain Mental and Orientation Status Assessment for Intensive Care (MD-MOSAIC). MD-MOSAIC serves as a multi-dimensional approach to expand upon the conventional mental status exam for mechanically ventilated patients with critical illness and AMS. By combining this modified mental status exam with a focal physical (including neurologic) exam, this framework provides a systematic approach to reinterpret the conventional psychiatric assessment as it applies to patients with critical illness. Drawing upon experience integrating consultation-liaison psychiatry into the intensive care setting, we aim to share this skill set with the psychiatric community.^10,11

In this guide, we have included strategies for psychiatrists to navigate the mental status exam, a focal physical and neurologic assessment, and other essential neurocognitive findings in the intensive care setting. These strategies can help to facilitate psychiatry’s further expansion into the ICU setting, as evaluating mechanically ventilated patients or other common elements of critical care may otherwise be unfamiliar to many psychiatrists and mental health clinicians. Using this framework, psychiatrists can utilize a systematic approach to reinterpret elements of the mental status exam of a noncommunicative patient population. Ultimately, this guide can help psychiatrists and mental health clinicians to optimize their approach to prioritizing a clinically relevant and comprehensive differential diagnosis for delirium and other causes of AMS, further strengthening the role of psychiatrists in the treatment of health care’s sickest patients.

Current Gaps in Assessing and Managing Delirium

Despite efforts to enhance delirium curriculum in the education of various medical specialties, knowledge gaps persist. In a review of studies exploring surgical trainees’ educational experiences with geriatric patients, some of the widest knowledge gaps were noted in the assessment and management of delirium.¹² In a previous study of medical and surgical service patients receiving psychiatric consultation, the diagnosis of delirium was missed in 46% of psychiatric consultations.¹³ Additionally, rates of misdiagnosis of delirium have ranged from 41% in the acute care setting to 69% in the medical-surgical intensive care setting, suggesting specific challenges when assessing the cognition and other delirium features of patients with critical illness.¹⁴ The under-recognition of delirium in various clinical settings highlights limitations in physician knowledge about this complex neuropsychiatric condition and its assessment, prevention, and management strategies.

Delirium’s under-recognition also contributes to worsened longitudinal patient outcomes, as the burden of delirium tends to impact these outcomes in a “dose-dependent” manner.³ A patient with critical illness who has experienced a longer course of delirium also faces higher mortality rates at 6 months and 12 months following critical illness.^6,15 For ICU survivors, their duration of delirium is an independent predictor of functional disabilities, including difficulty with activities of daily living and motor-sensory functioning.¹⁶ Ultimately, with longer and more severe courses of delirium, patients face worse long-term outcomes.

Although delirium is highly prevalent in the ICU, psychiatric involvement in the intensive care setting has been historically limited. The rate of psychiatric consultation in the ICU is significantly lower than on general medical units. In a study of 56 different clinical services, approximately 3% of psychiatric consults originated in the intensive care setting, compared with 75% to 80% of psychiatric consults from general medical units.¹⁷ Low rates of psychiatric consultation in the intensive care setting could be driven by communication barriers faced by patients with critical illness, especially those requiring mechanical ventilation. Additionally, these limitations in collaboration are likely shaped by the perspectives of both intensivists and psychiatrists. Historically, intensivists have grown accustomed to managing a patient’s psychiatric symptoms without the involvement of a psychiatry team, while psychiatrists have not fully embraced opportunities to engage with patients with critical illness, with some deferring these encounters until patients have been extubated or their acute conditions have stabilized (eg, “I will see the patient once they are alert and verbal”).¹⁰

Strategies to Improve the Identification of and Interventions for Delirium

One potential solution to optimize psychiatric involvement in the intensive care setting is the utilization of proactive psychiatric consultation.^11,18 With this model of care, a cohort of patients is systematically screened using predetermined criteria, followed by an order for psychiatric consultation for patients meeting eligibility. Using objective screening criteria facilitates more equitable distribution of psychiatric resources.¹⁹ The proactive model has been associated with improvements in clinical outcomes,^18-21 staff satisfaction,^20,22 and financial outcomes^21,23 among general medical inpatients, as well as improved clinical outcomes for patients with delirium and respiratory failure in the medical ICU.^24,25

To best equip psychiatrists and mental health clinicians to be advocates for ICU patients with delirium, it is necessary to provide them with the tools to conduct mental status exams on patients with critical illness. These tools include special considerations for communication barriers, such as mechanical ventilation. Additionally, empowering psychiatrists and mental health clinicians to perform a focused physical exam and to interpret laboratory values, neuroimaging, and other objective data is expected to improve their opportunities to synthesize this information into a broad and clinically appropriate differential diagnosis.

Standardizing a systematic approach to the mental status examinations of patients with critical illness is crucial. By prioritizing consistency with individual patient evaluations and educating our colleagues in other specialties, we can best advocate for all critically ill patients with delirium. Two commonly used validated tools for screening for delirium in patients with critical illness include the Confusion Assessment Method (CAM) for the intensive care unit (CAM-ICU) and the Intensive Care Delirium Screening Checklist.²⁶ In initial studies by Ely et al, the CAM-ICU was found to have excellent validity and reliability, with a demonstrated sensitivity of 93% to 100%, a specificity of 98% to 100%, and high interrater reliability (κ = 0.96) in the detection of delirium.^27,28 A Cochrane meta-analysis demonstrated a pooled sensitivity of 0.78 (95% confidence interval (CI) 0.72 to 0.83) and a pooled specificity of 0.95 (95% CI 0.92 to 0.97) for the CAM-ICU.²⁹ A subsequent study highlighted potential limitations of the CAM-ICU; when using unstructured assessments, rather than CAM-ICU, a higher proportion of patients with delirium were identified (36.7% vs 21.3%, P = 0.004).³⁰ The ICDSC identifies delirium through the systematic assessment of 8 symptom domains including altered level of consciousness, inattention, disorientation, psychotic symptoms, motor symptoms, inappropriate mood or speech, sleep disturbances and fluctuating course, observed over a 24-hour period.³¹ A score of 4 of more indicates delirium with a predicted sensitivity of 99% and specificity of 64%.³¹ The ICDSC also identifies patients with “subsyndromal” delirium, who are at risk for becoming delirious but do not yet meet full diagnostic criteria. While these instruments are useful for delirium screening, they are insufficient as standalone tools for psychiatrists practicing in the ICU setting.

Another useful instrument for evaluating critically ill patients is the Johns Hopkins Adapted Cognitive Exam (ACE), which has been studied in both intubated and nonintubated patients in the intensive care setting.³²While the ACE is a validated test for broadly assessing cognition, it may be less useful for patients with delirium, as multiple different components of this exam require the patient to have intact attention. For example, the first question reads, “Is the year0) blue 1) 1842 2) 2003 3) current year,” with distractor responses receiving no points. Incorrect but relevant responses receiving 1-2 points, and the correct response receiving 3 points. The complexity of this framework may be challenging for delirious patients with impaired attention, who might disengage with the examiner. The MD-MOSAIC evaluation is designed to facilitate patient engagement through the use of simple questions which reinforce patient orientation and safety; it should be considered as a clinically useful resource among patients whose AMS limits their engagement with more formal assessments of cognition.

Adapting the MD-MOSAIC

The MD-MOSAIC (Table 1) combines key domains assessed in the Mini-Mental State Examination (MMSE), and the Montreal Cognitive Assessment (MoCA) to evaluate a patient’s level of consciousness, attention & calculation, orientation (temporal, spatial, situational), language, executive functioning, registration, and delayed recall. It is worth noting that unlike the ICDSC, MMSE, MoCA, and ACE, MD-MOSAIC does not have a numerical scoring system, nor is it a validated tool. Rather, it is a resource that was created by practitioners operating in the critical care environment as a resource for the field, and which can be used to guide the psychiatrist’s evaluation of patients with critical illness by identifying impairments in these neurocognitive domains. Given the high incidence of impaired communication among patients with critical illness, in lieu of verbal responses, this exam is compatible with nonverbal responses such as head nodding/shaking or purposeful movements of the extremities. Incorrect responses provide the examiner with an opportunity to reorient the patient and then assess registration by asking the same question again later during the interview. The framework can also be used during subsequent encounters, permitting the examiner to cultivate a more nuanced understanding of affected clinical domains over multiple assessments. In this manner, the MD-MOSAIC framework seeks to provide both a diagnostic and therapeutic approach to evaluating the mental status of critically ill patients, thus enhancing the patient’s contextual understanding of their current clinical situation.

Supplementing Mental Status Examination

Patients who can successfully participate in this exam may be able to take part in a more comprehensive psychiatric examination with appropriate reframing adapted to their means of communication. For example, if a ventilated patient can reliably nod and shake their head to indicate yes or no, the remainder of a typical psychiatric evaluation can be reframed to yes or no questions. Questions should be asked in a simple, straightforward manner to force a binary yes/no response. Several examples are listed here. Compound, or 2-part questions should be avoided.

• “Do you regularly drink alcohol?”
• “Do you take any psychotropic medications?”
• “Do you feel safe here in the hospital?”

These questions make up a small sample of the many questions that can be asked in this yes/no manner with the aim of conducting a thorough psychiatric evaluation, if possible.

Focal Neurologic Exam for Patients With Delirium Requiring Mechanical Ventilation

Table 2 provides a focal physical exam that starts at the patient’s head proceeds downward to identify subtle physical exam findings indicative of conditions that may be challenging to characterize in a noncommunicative patient.

Using the MD-MOSAIC Tool to Communicate Findings to the Primary Team

For a patient receiving psychiatric consultation for altered mental status, the psychiatrist can collaborate with the primary team to ensure that a clinically appropriate work-up for reversible and irreversible causes of AMS has been pursued. Where possible, the psychiatric consultant’s assessment and plan should utilize language from the ABCDEF Bundle and other evidence-based critical care frameworks.^10,11,33 It is worth noting that certain physical exam findings discovered during the psychiatric evaluation may be suggestive of acute conditions that require escalation of care. Some examples include focal neurological findings requiring emergent neuroimaging, pinpoint pupils, and bradypnea requiring naloxone, or a suspected seizure requiring antiepileptic drug administration.

Given delirium’s prevalence in the critical care setting and its potential to significantly worsen numerous downstream clinical and neuropsychiatric outcomes, the psychiatric consultant can significantly improve a patient’s course of care through the early identification and management of delirium. Often, the initial workup for and management of delirium remains focused on the cognitive and other psychiatric aspects, identifying and treating agitation, confusion, and disorientation. However, as delirium itself is a multifactorial condition, involving physiologic, pharmacologic, and iatrogenic causes, the diagnostic approach must also remain broad. The MD-MOSAIC model provides a framework for clinicians to expand on their usual approach to evaluating AMS in a manner that can be more conducive to those with critical illness, highlighting key neurologic and physical exam features and their associated conditions. This approach may help identify the precipitating factors for a patient’s delirium or may uncover alternative causes of AMS. With this awareness, the psychiatric consultant can support the primary physician team as they develop targeted treatment for AMS and its underlying causes. The proposed MD-MOSAIC exam could be prospectively validated by comparisons with and among other accepted measures for the assessment of altered mental status, including delirium.

Ultimately, delirium is a nuanced, dynamic condition that can have long-reaching effects on the patient’s mortality and morbidity. Delirium’s impact can extend far beyond the hospitalization, as survivors of critical illness commonly develop cognitive, psychological or functional sequelae known as post ICU syndrome.³⁴ Early intervention for delirium has the potential to shorten admission length, reduce the need for prolonged chemical or physical restraints, and improve post-discharge prognosis. It is the role of the psychiatrist to accurately and reliably evaluate a patient with AMS to diagnose delirium, identify contributory factors and, in conjunction with the primary team, tailor treatment to each patient and their specific presentation. It is our hope the MD-MOSAIC model can aid psychiatrists with achieving this goal.

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