Cognitive stimulation in ICU patients: should we pay more attention?

Patients' experiences of cognitive impairment following critical illness: a scoping review protocol

INTRODUCTION

Critical illness and admission to an intensive care unit (ICU) can affect patients for months or years following discharge as many suffer from cognitive impairment. Long-term cognitive impairment affects patients' quality of life and ability to adapt to everyday life. Exploring their experiences on how and which cognitive impairments are affecting their everyday lives facilitates planning of relevant research on interventions that may serve to alleviate the burden of post-ICU cognitive impairment. The objective of this scoping review is to map the existing research on patients' experiences of cognitive impairment following critical illness.

METHODS AND ANALYSIS

The methodology will follow the Joanna Briggs Institute guidelines for scoping reviews. The databases MEDLINE, CINAHL, PsycINFO and Embase will be searched to identify studies appropriate for inclusion. Any peer-reviewed original studies meeting the inclusion criteria and include statements from adult patients about how they experience cognitive impairment following critical illness and ICU admission will be considered. Studies published in English and Scandinavian languages will be included, with no further geographical or cultural limitations. The included studies will be screened by two independent researchers using a standardised data extraction tool and the Mixed Methods Appraisal Tool will be used for critical appraisal. The results will be presented in a tabular form, and data will be supported by narrative descriptions or a narrative summary.

ETHICS AND DISSEMINATION

Since the scoping review methodology aims at synthetising existing research on patients' experiences of cognitive impairment following critical illness, the scoping review does not require ethical approval. The results will be disseminated though a peer-reviewed publication in a scientific journal.

Mechanisms involved in brain dysfunction in mechanically ventilated critically ill patients: implications and therapeutics

Critical illness may lead to significant long-term neurological morbidity and patients frequently develop neuropsychological disturbances including acute delirium or memory impairment after intensive care unit (ICU) discharge. Mechanical ventilation (MV) is a risk factor to the development of adverse neurocognitive outcomes. Patients undergoing MV for long periods present neurologic impairment with memory and cognitive alteration. Delirium is considered an acute form of brain dysfunction and its prevalence rises in mechanically ventilated patients. Delirium duration is an independent predictor of mortality, ventilation time, ICU length of stay and short- and long-term cognitive impairment in the ICU survivors. Although, neurocognitive sequelae tend to improve after hospital discharge, residual deficits persist even 6 years after ICU stay. ICU-related neurocognitive impairments occurred in many cognitive domains and are particularly pronounced with regard to memory, executive functions, attentional functions, and processing speed. These sequelae have an important impact on patients' lives and ICU survivors often require institutionalization and hospitalization. Experimental studies have served to explore the possible mechanisms or pathways involved in this lung to brain interaction. This communication can be mediated via a complex web of signaling events involving neural, inflammatory, immunologic and neuroendocrine pathways. MV can affect respiratory networks and the application of protective ventilation strategies is mandatory in order to prevent adverse effects. Therefore, strategies focused to minimize lung stretch may improve outcomes, avoiding failure of distal organ, including the brain. Long-term neurocognitive impairments experienced by critically ill survivors may be mitigated by early interventions, combining cognitive and physical therapies. Inpatient rehabilitation interventions in ICU promise to improve outcomes in critically ill patients. The cross-talk between lung and brain, involving specific pathways during critical illness deserves further efforts to evaluate, prevent and improve cognitive alterations after ICU admission, and highlights the crucial importance of tailoring MV to prevent adverse outcomes.

Visuo-acoustic stimulation that helps you to relax: A virtual reality setup for patients in the intensive care unit

After prolonged stay in an intensive care unit (ICU) patients often complain about cognitive impairments that affect health-related quality of life after discharge. The aim of this proof-of-concept study was to test the feasibility and effects of controlled visual and acoustic stimulation in a virtual reality (VR) setup in the ICU. The VR setup consisted of a head-mounted display in combination with an eye tracker and sensors to assess vital signs. The stimulation consisted of videos featuring natural scenes and was tested in 37 healthy participants in the ICU. The VR stimulation led to a reduction of heart rate (p = 0. 049) and blood pressure (p = 0.044). Fixation/saccade ratio (p < 0.001) was increased when a visual target was presented superimposed on the videos (reduced search activity), reflecting enhanced visual processing. Overall, the VR stimulation had a relaxing effect as shown in vital markers of physical stress and participants explored less when attending the target. Our study indicates that VR stimulation in ICU settings is feasible and beneficial for critically ill patients.

Feasibility and safety of virtual-reality-based early neurocognitive stimulation in critically ill patients

Background

Growing evidence suggests that critical illness often results in significant long-term neurocognitive impairments in one-third of survivors. Although these neurocognitive impairments are long-lasting and devastating for survivors, rehabilitation rarely occurs during or after critical illness. Our aim is to describe an early neurocognitive stimulation intervention based on virtual reality for patients who are critically ill and to present the results of a proof-of-concept study testing the feasibility, safety, and suitability of this intervention.

Methods

Twenty critically ill adult patients undergoing or having undergone mechanical ventilation for ≥24 h received daily 20-min neurocognitive stimulation sessions when awake and alert during their ICU stay. The difficulty of the exercises included in the sessions progressively increased over successive sessions. Physiological data were recorded before, during, and after each session. Safety was assessed through heart rate, peripheral oxygen saturation, and respiratory rate. Heart rate variability analysis, an indirect measure of autonomic activity sensitive to cognitive demands, was used to assess the efficacy of the exercises in stimulating attention and working memory.

Results

Patients successfully completed the sessions on most days. No sessions were stopped early for safety concerns, and no adverse events occurred. Heart rate variability analysis showed that the exercises stimulated attention and working memory. Critically ill patients considered the sessions enjoyable and relaxing without being overly fatiguing.

Conclusions

The results in this proof-of-concept study suggest that a virtual-reality-based neurocognitive intervention is feasible, safe, and tolerable, stimulating cognitive functions and satisfying critically ill patients. Future studies will evaluate the impact of interventions on neurocognitive outcomes.

Trial registration Clinical trials.gov identifier: NCT02078206

Electronic supplementary material

The online version of this article (doi:10.1186/s13613-017-0303-4) contains supplementary material, which is available to authorized users.

Moderate Peep After Tracheal Lipopolysaccharide Instillation Prevents Inflammation and Modifies the Pattern of Brain Neuronal Activation

Background:

Ventilatory strategy and specifically positive end-expiratory pressure (PEEP) can modulate the inflammatory response and pulmonary-to-systemic translocation of lipopolysaccharide (LPS). Both inflammation and ventilatory pattern may modify brain activation, possibly worsening the patient's outcome and resulting in cognitive sequelae.

Methods:

We prospectively studied Sprague–Dawley rats randomly assigned to undergo 3 h mechanical ventilation with 7 mL/kg tidal ventilation and either 2 cmH₂O or 7 cmH₂O PEEP after intratracheal instillation of LPS or saline. Healthy nonventilated rats served as baseline. We analyzed lung mechanics, gas exchange, lung and plasma cytokine levels, lung apoptotic cells, and lung neutrophil infiltration. To evaluate brain neuronal activation, we counted c-Fos immunopositive cells in the retrosplenial cortex (RS), thalamus, supraoptic nucleus (SON), nucleus of the solitary tract (NTS), paraventricular nucleus (PVN), and central amygdala (CeA).

Results:

LPS increased lung neutrophilic infiltration, lung and systemic MCP-1 levels, and neuronal activation in the CeA and NTS. LPS-instilled rats receiving 7 cmH₂O PEEP had less lung and systemic inflammation and more c-Fos-immunopositive cells in the RS, SON, and thalamus than those receiving 2 cmH₂O PEEP. Applying 7 cmH₂O PEEP increased neuronal activation in the CeA and NTS in saline-instilled rats, but not in LPS-instilled rats.

Conclusions:

Moderate PEEP prevented lung and systemic inflammation secondary to intratracheal LPS instillation. PEEP also modified the neuronal activation pattern in the RS, SON, and thalamus. The relevance of these differential brain c-Fos expression patterns in neurocognitive outcomes should be explored.