Entropy and bispectral index for assessment of sedation, analgesia and the effects of unpleasant stimuli in critically ill patients: an observational study

Bispectral Index Monitoring in the Nursing of Patients With Paroxysmal Sympathetic Hyperactivity

AIM

To investigate the clinical nursing effect of bispectral index (BIS) monitoring for paroxysmal sympathetic hyperactivity (PSH) patients in the neurosurgical intensive care unit (NICU).

METHODS

From January 2022 to June 2023, a total of 30 patients with PSH secondary to moderate to severe craniocerebral injury in the NICU were monitored for BIS. The patients' paroxysmal sympathetic hyperactivity-assessment measure (PSH-AM) scores were recorded. PSH patients generally appear in 3 states: calm state, seizure state, and postmedication state. Thirty PSH patients' BIS values were recorded during the calm period, during the seizure state, and postmedication state, and these 3 different stages' BIS values were divided into groups A, B, and C, using the Kruskal-Wallis H test to compare groups.

RESULTS

The Kruskal-Wallis H test yielded a value of H=22.599, P <0.001. H0 was rejected against the test standard of α=0.05, and the BIS values of groups A, B, and C differed. The BIS values of group A and group B differed after a pairwise comparison, and the difference was statistically significant (adjusted P =0.001). Group B and group C had different BIS values, and the difference was statistically significant (adjusted P =0.001); group A and Group C had no difference in BIS values, and the difference was not statistically significant (adjusted P =1.00).

CONCLUSIONS

Taking BIS value as the nursing observation index for PSH patients can make nursing work more objective, reasonable, and accurate, reduce the inducing factors of PSH attack, further reduce the attack of PSH, save nursing resources, and help guide the safety assessment of sedative use.

Electrophysiological monitoring of neurological functions at the acute phase of brain injury: An overview of current knowledge and future perspectives in the adult population

The continuous monitoring of physiological parameters is now considered as a standard of care in intensive care units (ICU). While multiple techniques are available to guide hemodynamic or respiratory management, the monitoring of neurological function in unconscious patients is usually limited to discontinuous bedside neurological examination or morphological brain imaging. However, cortical activity is accessible at the bedside with electroencephalography (EEG), electrocorticography (ECoG) or evoked potentials. The analysis of the unprocessed signal requires a trained neurophysiologist and could be time consuming. During the past decades, advances in neurophysiological signal acquisition make it possible to calculate quantified EEG parameters in real-time. New monitors also provide ICU friendly display for a dynamic and live assessment of neurological function changes. In this review, we will describe the technical aspects of EEG, ECoG and evoked potentials required for a good signal quality before interpretation. We will discuss how to use those electrophysiological techniques in the ICU to assess neurological function in comatose patients at the acute phase of brain injuries such as traumatic brain injuries, haemorrhagic or ischemic stroke. We will discuss, which quantitative EEG or evoked potentials monitoring parameters can be used at the bedside to guide sedation, evaluate neurological function during awaking and look for new neurological (encephalic or brainstem) injuries. We will present the state of the art and discuss some analyses, which may develop shortly.

Strategy and Philosophy for Treating Pain and Sleep in Disorders of Consciousness

Despite the evolving practice of brain injury medicine, consciousness remains enigmatic. Most patients with disorders of consciousness have disordered sleep and return of normal sleep architecture is essential to the emergence of consciousness and the healing brain. In this article we lay a framework for understanding the emergence of consciousness in brain-injured patients. We then explore ways to use that framework to evaluate and tailor treatment of sleep and pain in patients with disorders of consciousness. Although more research is needed to empower better treatment in the future, validated tools now exist for evaluation of emergent consciousness, pain, and sleep.

Adaptive Sedation Monitoring From EEG in ICU Patients With Online Learning

Sedative medications are routinely administered to provide comfort and facilitate clinical care in critically ill ICU patients. Prior work shows that brain monitoring using electroencephalography (EEG) to track sedation levels may help medical personnel to optimize drug dosing and avoid the adverse effects of oversedation and undersedation. However, the performance of sedation monitoring methods proposed to date deal poorly with individual variability across patients, leading to inconsistent performance. To address this challenge we develop an online learning approach based on Adaptive Regularization of Weight Vectors (AROW). Our approach adaptively updates a sedation level prediction algorithm under a continuously evolving data distribution. The prediction model is gradually calibrated for individual patients in response to EEG observations and routine clinical assessments over time. The evaluations are performed on a population of 172 sedated ICU patients whose sedation levels were assessed using the Richmond Agitation-Sedation Scale (scores between -5 = comatose and 0 = awake). The proposed adaptive model achieves better performance than the same model without adaptation (average accuracies with tolerance of one level difference: 68.76% vs. 61.10%). Moreover, our approach is shown to be robust to sudden changes caused by label noise. Medication administrations have different effects on model performance. We find that the model performs best in patients receiving only propofol, compared to patients receiving no sedation or multiple simultaneous sedative medications.

Clinical Practice Guidelines for the Prevention and Management of Pain, Agitation/Sedation, Delirium, Immobility, and Sleep Disruption in Adult Patients in the ICU

OBJECTIVE

To update and expand the 2013 Clinical Practice Guidelines for the Management of Pain, Agitation, and Delirium in Adult Patients in the ICU.

DESIGN

Thirty-two international experts, four methodologists, and four critical illness survivors met virtually at least monthly. All section groups gathered face-to-face at annual Society of Critical Care Medicine congresses; virtual connections included those unable to attend. A formal conflict of interest policy was developed a priori and enforced throughout the process. Teleconferences and electronic discussions among subgroups and whole panel were part of the guidelines' development. A general content review was completed face-to-face by all panel members in January 2017.

METHODS

Content experts, methodologists, and ICU survivors were represented in each of the five sections of the guidelines: Pain, Agitation/sedation, Delirium, Immobility (mobilization/rehabilitation), and Sleep (disruption). Each section created Population, Intervention, Comparison, and Outcome, and nonactionable, descriptive questions based on perceived clinical relevance. The guideline group then voted their ranking, and patients prioritized their importance. For each Population, Intervention, Comparison, and Outcome question, sections searched the best available evidence, determined its quality, and formulated recommendations as "strong," "conditional," or "good" practice statements based on Grading of Recommendations Assessment, Development and Evaluation principles. In addition, evidence gaps and clinical caveats were explicitly identified.

RESULTS

The Pain, Agitation/Sedation, Delirium, Immobility (mobilization/rehabilitation), and Sleep (disruption) panel issued 37 recommendations (three strong and 34 conditional), two good practice statements, and 32 ungraded, nonactionable statements. Three questions from the patient-centered prioritized question list remained without recommendation.

CONCLUSIONS

We found substantial agreement among a large, interdisciplinary cohort of international experts regarding evidence supporting recommendations, and the remaining literature gaps in the assessment, prevention, and treatment of Pain, Agitation/sedation, Delirium, Immobility (mobilization/rehabilitation), and Sleep (disruption) in critically ill adults. Highlighting this evidence and the research needs will improve Pain, Agitation/sedation, Delirium, Immobility (mobilization/rehabilitation), and Sleep (disruption) management and provide the foundation for improved outcomes and science in this vulnerable population.

Current Use of Neuromuscular Blocking Agents in Intensive Care Units

Neuromuscular blocking agents can be used for purposes such as eliminating ventilator-patient dyssynchrony, facilitating gas exchange by reducing intra-abdominal pressure and improving chest wall compliance, reducing risk of lung barotrauma, decreasing contribution of muscles to oxygen consumption by preventing shivering and limiting elevations in intracranial pressure caused by airway stimulation in patients supported with mechanical ventilation in intensive care units. Adult Respiratory Distress Syndrome (ARDS), status asthmaticus, increased intracranial pressure and therapeutic hypothermia following ventricular fibrillation-associated cardiac arrest are some of clinical conditions that can be sustained by neuromuscular blockade. Appropriate indication and clinical practice have gained importance considering side effects such as ICU-acquired weakness, masking seizure activity and longer durations of hospital and ICU stays. We mainly aimed to review the current literature regarding neuromuscular blockade in up-to-date clinical conditions such as improving oxygenation in early ARDS and preventing shivering in the therapeutic hypothermia along with summarising the clinical practice in adult ICU in this report.

Use of the critical-care pain observation tool and the bispectral index for the detection of pain in brain-injured patients undergoing mechanical ventilation: A STROBE-compliant observational study

The assessment of pain in patients with brain injury is challenging due to impaired ability to communicate. We aimed to test the reliability and validity of the critical-care pain observation tool (CPOT) and the bispectral index (BIS) for pain detection in critically brain-injured patients.This prospective observational study was conducted in a neurosurgical intensive care unit in a University-Affiliated Hospital. Adult brain-injured patients undergoing mechanical ventilation were enrolled. Nociceptive (endotracheal suctioning) and non-nociceptive (gentle touching) procedures were performed in a random crossover fashion. Before and immediately after the procedure, CPOT was evaluated by 2 residents and 2 chief nurses, and BIS was documented. The ability to self-report pain was also assessed. The inter-observer reliability of CPOT was analyzed. The criterion and discriminant validities of the CPOT and the BIS were tested.During the study, we enrolled 400 brain-injured patients. The ability to self-report pain was maintained in 214 (54%) and 218 (55%) patients during suctioning and gentle touching, respectively. The intraclass correlation coefficients (95% confidence interval) for inter-observer reliability of CPOT ranged from 0.86 (0.83-0.89) to 0.93 (0.91-0.94). Using self-reported pain as the reference, the area under the receiver operating characteristic curve (95% confidence interval) was 0.84 (0.80-0.88) for CPOT and 0.76 (0.72-0.81) for BIS. When the 2 instruments were combined as either CPOT ≥2 or BIS ≥88 after the procedure, the sensitivity and specificity were 0.90 (0.85-0.93) and 0.59 (0.52-0.66), respectively; and when the 2 instruments were combined as both CPOT ≥2 and BIS ≥88, the sensitivity and specificity were 0.62 (0.55-0.68) and 0.89 (0.83-0.93). Both CPOT and BIS increased significantly after suctioning (all P < .001) but remained unchanged after gentle touching (P ranging from .06 to .14).Our criterion and discriminant validity results supported the use of CPOT and BIS to detect pain in critically brain-injured patients. Combining use of CPOT and BIS in different ways might provide comprehensive pain assessment for different purposes.

Electroencephalogram Based Detection of Deep Sedation in ICU Patients Using Atomic Decomposition

OBJECTIVE

This study was performed to evaluate how well states of deep sedation in ICU patients can be detected from the frontal electroencephalogram (EEG) using features based on the method of atomic decomposition (AD).

METHODS

We analyzed a clinical dataset of 20 min of EEG recordings per patient from 44 mechanically ventilated adult patients receiving sedatives in an intensive care unit (ICU) setting. Several features derived from AD of the EEG signal were used to discriminate between awake and sedated states. We trained support vector machine (SVM) classifiers using AD features and compared the classification performance with SVM classifiers trained using standard spectral and entropy features using leave-one-subject-out validation. The potential of each feature to discriminate between awake and sedated states was quantified using area under the receiver operating characteristic curve (AUC).

RESULTS

The sedation level classification system using AD was able to reliably discriminate between sedated and awake states achieving an average AUC of 0.90, which was significantly better () than performance achieved using spectral (AUC = 0.86) and entropy (AUC = 0.81) domain features. A combined feature set consisting of AD, entropy, and spectral features provided better discrimination (AUC = 0.91, ) than any individual feature set.

CONCLUSIONS

Features derived from the atomic decomposition of EEG signals provide useful discriminative information about the depth of sedation in ICU patients.

SIGNIFICANCE

With further refinement and external validation, the proposed system may be able to assist clinical staff with continuous surveillance of sedation levels in mechanically ventilated critically ill ICU patients.

Clinical Practice Guidelines for Sustained Neuromuscular Blockade in the Adult Critically Ill Patient

OBJECTIVE

To update the 2002 version of "Clinical practice guidelines for sustained neuromuscular blockade in the adult critically ill patient."

DESIGN

A Task Force comprising 17 members of the Society of Critical Medicine with particular expertise in the use of neuromuscular-blocking agents; a Grading of Recommendations Assessment, Development, and Evaluation expert; and a medical writer met via teleconference and three face-to-face meetings and communicated via e-mail to examine the evidence and develop these practice guidelines. Annually, all members completed conflict of interest statements; no conflicts were identified. This activity was funded by the Society for Critical Care Medicine, and no industry support was provided.

METHODS

Using the Grading of Recommendations Assessment, Development, and Evaluation system, the Grading of Recommendations Assessment, Development, and Evaluation expert on the Task Force created profiles for the evidence related to six of the 21 questions and assigned quality-of-evidence scores to these and the additional 15 questions for which insufficient evidence was available to create a profile. Task Force members reviewed this material and all available evidence and provided recommendations, suggestions, or good practice statements for these 21 questions.

RESULTS

The Task Force developed a single strong recommendation: we recommend scheduled eye care that includes lubricating drops or gel and eyelid closure for patients receiving continuous infusions of neuromuscular-blocking agents. The Task Force developed 10 weak recommendations. 1) We suggest that a neuromuscular-blocking agent be administered by continuous intravenous infusion early in the course of acute respiratory distress syndrome for patients with a PaO2/FIO2 less than 150. 2) We suggest against the routine administration of an neuromuscular-blocking agents to mechanically ventilated patients with status asthmaticus. 3) We suggest a trial of a neuromuscular-blocking agents in life-threatening situations associated with profound hypoxemia, respiratory acidosis, or hemodynamic compromise. 4) We suggest that neuromuscular-blocking agents may be used to manage overt shivering in therapeutic hypothermia. 5) We suggest that peripheral nerve stimulation with train-of-four monitoring may be a useful tool for monitoring the depth of neuromuscular blockade but only if it is incorporated into a more inclusive assessment of the patient that includes clinical assessment. 6) We suggest against the use of peripheral nerve stimulation with train of four alone for monitoring the depth of neuromuscular blockade in patients receiving continuous infusion of neuromuscular-blocking agents. 7) We suggest that patients receiving a continuous infusion of neuromuscular-blocking agent receive a structured physiotherapy regimen. 8) We suggest that clinicians target a blood glucose level of less than 180 mg/dL in patients receiving neuromuscular-blocking agents. 9) We suggest that clinicians not use actual body weight and instead use a consistent weight (ideal body weight or adjusted body weight) when calculating neuromuscular-blocking agents doses for obese patients. 10) We suggest that neuromuscular-blocking agents be discontinued at the end of life or when life support is withdrawn. In situations in which evidence was lacking or insufficient and the study results were equivocal or optimal clinical practice varies, the Task Force made no recommendations for nine of the topics. 1) We make no recommendation as to whether neuromuscular blockade is beneficial or harmful when used in patients with acute brain injury and raised intracranial pressure. 2) We make no recommendation on the routine use of neuromuscular-blocking agents for patients undergoing therapeutic hypothermia following cardiac arrest. 3) We make no recommendation on the use of peripheral nerve stimulation to monitor degree of block in patients undergoing therapeutic hypothermia. 4) We make no recommendation on the use of neuromuscular blockade to improve the accuracy of intravascular-volume assessment in mechanically ventilated patients. 5) We make no recommendation concerning the use of electroencephalogram-derived parameters as a measure of sedation during continuous administration of neuromuscular-blocking agents. 6) We make no recommendation regarding nutritional requirements specific to patients receiving infusions of neuromuscular-blocking agents. 7) We make no recommendation concerning the use of one measure of consistent weight over another when calculating neuromuscular-blocking agent doses in obese patients. 8) We make no recommendation on the use of neuromuscular-blocking agents in pregnant patients. 9) We make no recommendation on which muscle group should be monitored in patients with myasthenia gravis receiving neuromuscular-blocking agents. Finally, in situations in which evidence was lacking or insufficient but expert consensus was unanimous, the Task Force developed six good practice statements. 1) If peripheral nerve stimulation is used, optimal clinical practice suggests that it should be done in conjunction with assessment of other clinical findings (e.g., triggering of the ventilator and degree of shivering) to assess the degree of neuromuscular blockade in patients undergoing therapeutic hypothermia. 2) Optimal clinical practice suggests that a protocol should include guidance on neuromuscular-blocking agent administration in patients undergoing therapeutic hypothermia. 3) Optimal clinical practice suggests that analgesic and sedative drugs should be used prior to and during neuromuscular blockade, with the goal of achieving deep sedation. 4) Optimal clinical practice suggests that clinicians at the bedside implement measure to attenuate the risk of unintended extubation in patients receiving neuromuscular-blocking agents. 5) Optimal clinical practice suggests that a reduced dose of an neuromuscular-blocking agent be used for patients with myasthenia gravis and that the dose should be based on peripheral nerve stimulation with train-of-four monitoring. 6) Optimal clinical practice suggests that neuromuscular-blocking agents be discontinued prior to the clinical determination of brain death.

Staff education, regular sedation and analgesia quality feedback, and a sedation monitoring technology for improving sedation and analgesia quality for critically ill, mechanically ventilated patients: a cluster randomised trial

BACKGROUND

Optimal sedation of patients in intensive care units (ICUs) requires the avoidance of pain, agitation, and unnecessary deep sedation, but these outcomes are challenging to achieve. Excessive sedation can prolong ICU stay, whereas light sedation can increase pain and frightening memories, which are commonly recalled by ICU survivors. We aimed to assess the effectiveness of three interventions to improve sedation and analgesia quality: an online education programme; regular feedback of sedation-analgesia quality data; and use of a novel sedation-monitoring technology (the Responsiveness Index [RI]).

METHODS

We did a cluster randomised trial in eight ICUs, which were randomly allocated to receive education alone (two ICUs), education plus sedation-analgesia quality feedback (two ICUs), education plus RI monitoring technology (two ICUs), or all three interventions (two ICUs). Randomisation was done with computer-generated random permuted blocks, stratified according to recruitment start date. A 45 week baseline period was followed by a 45 week intervention period, separated by an 8 week implementation period in which the interventions were introduced. ICU and research staff were not masked to study group assignment during the intervention period. All mechanically ventilated patients were potentially eligible. We assessed patients' sedation-analgesia quality for each 12 h period of nursing care, and sedation-related adverse events daily. Our primary outcome was the proportion of care periods with optimal sedation-analgesia, defined as being free from excessive sedation, agitation, poor limb relaxation, and poor ventilator synchronisation. Analysis used multilevel generalised linear mixed modelling to explore intervention effects in a single model taking clustering and patient-level factors into account. A concurrent mixed-methods process evaluation was undertaken to help understand the trial findings. The trial is registered with ClinicalTrials.gov, number NCT01634451.

FINDINGS

Between June 1, 2012, and Dec 31, 2014, we included 881 patients (9187 care periods) during the baseline period and 591 patients (6947 care periods) during the intervention period. During the baseline period, optimal sedation-analgesia was present for 5150 (56%) care periods. We found a significant improvement in optimal sedation-analgesia with RI monitoring (odds ratio [OR] 1·44 [95% CI 1·07-1·95]; p=0·017), which was mainly due to increased periods free from excessive sedation (OR 1·59 [1·09-2·31]) and poor ventilator synchronisation (OR 1·55 [1·05-2·30]). However, more patients experienced sedation-related adverse events (OR 1·91 [1·02-3·58]). We found no improvement in overall optimal sedation-analgesia with education (OR 1·13 [95% CI 0·86-1·48]), but fewer patients experienced sedation-related adverse events (OR 0·56 [0·32-0·99]). The sedation-analgesia quality data feedback did not improve quality (OR 0·74 [95% CI 0·54-1·00]) or sedation-related adverse events (OR 1·15 [0·61-2·15]). The process evaluation suggested many clinicians found the RI monitoring useful, but it was often not used for decision making as intended. Education was valued and considered useful by staff. By contrast, sedation-analgesia quality feedback was poorly understood and thought to lack relevance to bedside nursing practice.

INTERPRETATION

Combination of RI monitoring and online education has the potential to improve sedation-analgesia quality and patient safety in mechanically ventilated ICU patients. The RI monitoring seemed to improve sedation-analgesia quality, but inconsistent adoption by bedside nurses limited its impact. The online education programme resulted in a clinically relevant improvement in patient safety and was valued by nurses, but any changes to behaviours did not seem to alter other measures of sedation-analgesia quality. Providing sedation-analgesia quality feedback to ICUs did not appear to improve any quality metrics, probably because staff did not think it relevant to bedside practice.

FUNDING

Chief Scientist Office, Scotland; GE Healthcare.

Hardin K. Inadequate Sedation During Therapeutic Paralysis: Use of Bispectral Index in Critically Ill Patients

Background

Patients receiving therapeutic paralysis may experience inadequate sedation due to intrinsic limitations of behavioral sedation assessment. Bispectral index (BIS™) provides an objective measure of sedation; however, the role of BIS™ is not well defined in intensive care unit (ICU) patients on neuromuscular blocking agents (NMBA).

Objective

The aim of this study was to delineate the relationship between BIS™ and level of sedation for critically ill patients during therapeutic paralysis.

Methods

This was a retrospective observational study conducted in ICU patients receiving continuous infusion NMBA and BIS™ monitoring. The primary endpoint was the correlation of BIS™ <60 during therapeutic paralysis with a Richmond Agitation Sedation Score (RASS) of −4 to −5 (i.e., deep or unarousable sedation) at the time of emergence from therapeutic paralysis.

Results

Thirty-one patients were included in the analysis. Three of these patients (9.6 %) were inadequately sedated upon emergence from paralysis; that is, restless or agitated (RASS +1 to +2). We did not observe a correlation between BIS™ and RASS upon emergence from paralysis (r = 0.27, p = 0.14). The sensitivity of BIS™ <60 in predicting deep sedation (RASS −5 to −4) was 100 % (95 % confidence interval [CI] 0–100) with a positive predictive value of 35.7 %. The sensitivity and positive predictive value of BIS™ <60 in predicting light sedation or deeper (RASS −5 to −2) was 92.9 % (95 %CI 83.3–100) and 92.9 %, respectively.

Conclusion

These results suggest that 1 in 10 critically ill patients receiving therapeutic paralysis may be inadequately sedated. BIS™ monitoring may serve as a useful adjunctive measure of sedation in critically ill patients receiving therapeutic paralysis.

Distancing sedation in end-of-life care from physician-assisted suicide and euthanasia

Lipuma equates continuous sedation until death (CSD) to physician-assisted suicide/euthanasia (PAS/E) based on the premise that iatrogenic unconsciousness negates social function and, thus, personhood, leaving a patient effectively 'dead'. Others have extrapolated upon this position further, to suggest that any use of sedation and/or opioids at the end of life would be analogous to CSD and thus tantamount to PAS/E. These posits sit diametrically opposite to standard end-of-life care practices. This paper will refute Lipuma's position and the posits borne from it. We first show that prevailing end-of-life care guidelines require proportional and monitored use of sedatives and/or opioids to attenuate fears that the use of such treatment could hasten death. These guidelines also classify CSD as a last resort treatment, employed only when symptoms prove intractable, and not amenable to all standard treatment options. Furthermore, CSD is applied only when deemed appropriate by a multidisciplinary palliative medicine team. We also show that empirical data based on local views of personhood will discount concerns that iatrogenic unconsciousness is tantamount to a loss of personhood and death.

A randomized controlled proof-of-concept trial of early sedation management using Responsiveness Index monitoring in mechanically ventilated critically ill patients

INTRODUCTION

Deep sedation is associated with adverse patient outcomes. We recently described a novel sedation-monitoring technology, the Responsiveness Index (RI), which quantifies patient arousal using processed frontal facial EMG data. We explored the potential effectiveness and safety of continuous RI monitoring during early intensive care unit (ICU) care as a nurse decision-support tool.

METHODS

In a parallel-group controlled single centre proof of concept trial, patients requiring mechanical ventilation and sedation were randomized via sequential sealed envelopes following ICU admission. Control group patients received hourly clinical sedation assessment and daily sedation holds; the RI monitor was connected but data were concealed from clinical staff. The intervention group received control group care, but RI monitoring was visible and nurses were asked to adjust sedation to maintain patients with an RI>20 whenever possible. Traffic-light colour coding (RI<20, Red; 20-40, Amber; >40, Green) simplified decision-making. The intervention lasted up to 48 hours. Sixteen nurses were interviewed to explore their views of the novel technology.

RESULTS

We analysed 74 patients treated per protocol (36 intervention; 38 control). The proportion of patients with RI<20 was identical at the start of monitoring (54% both groups). Overall, the proportion of time with RI<20 trended to lower values for the intervention group (median 16% (1-3rd quartile 8-30%) versus 33% (10-54%); P = 0.08); sedation and analgesic use was similar. A post hoc analysis restricted to patients with RI<20 when monitoring started, found intervention patients spent less time with low RI value (16% (11-45%) versus 51% (33-72%); P = 0.02), cumulative propofol use trended to lower values (median 1090 mg versus 2390 mg; P = 0.14), and cumulative alfentanil use was lower (21.2 mg versus 32.3 mg; P = 0.01). RASS scores were similar for both groups. Sedation related adverse event rates were similar (7/36 versus 5/38). Similar proportions of patients had sedation holds (83% versus 87 %) and were extubated (47% versus 44%) during the intervention period. Nurses valued the objective visible data trends and simple colour prompts, and found RI monitoring a useful adjunct to existing practice.

CONCLUSIONS

RI monitoring was safe and acceptable. Data suggested potential to modify sedation decision-making. Larger trials are justified to explore effects on patient-centred outcomes.

TRIAL REGISTRATION

NCT01361230 (registered April 19, 2010).

Entropy correlates with Richmond Agitation Sedation Scale in mechanically ventilated critically ill patients

Sedation is routinely used in intensive care units. However due to absence of objective scoring systems like Bispectral Index and entropy our ability to regulate the degree of sedation is limited. This deficiency is further highlighted by the fact that agitation scores used in intensive care units (ICU) have no role in paralyzed patients. The present study compares entropy as a sedation scoring modality with Richmond Agitation Sedation Scale (RASS) in mechanically ventilated, critically ill patients in an ICU. Twenty-seven, mechanically ventilated, critically ill patients of either sex, 16-65 years of age, were studied over a period of 24 h. They received a standard sedation regimen consisting of a bolus dose of propofol 0.5 mg/kg and fentanyl 1 lg/kg followed by infusions of propofol and fentanyl ranging from 1.5 to 5 mg/kg/h and 0.5 to 2.0 lg/kg/h, respectively. Clinically relevant values of RASS for optimal ICU sedation (between 0 and -3) in non-paralyzed patients were compared to corresponding entropy values, to find if any significant correlation exists between the two. These entropy measurements were obtained using the Datex-Ohmeda-M-EntropyTM module. This module is presently not approved by Food and Drug Administration (FDA) for monitoring sedation in ICU. A total of 527 readings were obtained. There was a statistically significant correlation between the state entropy (SE) and RASS [Spearman's rho/rs = 0.334, p\0.0001]; response entropy (RE) and RASS [Spearman's rho/rs = 0.341, p\0.0001]). For adequate sedation as judged by a RASS value of 0 to -3, the mean SE was 57.86 ± 16.50 and RE was 67.75 ± 15.65. The present study illustrates that entropy correlates with RASS (between scores 0 and -3) when assessing the level of sedation in mechanically ventilated critically ill patients.

The use of the bispectral index in the detection of pain in mechanically ventilated adults in the intensive care unit: a review of the literature

The bispectral index is a technique that involves assessing brain activity (through electroencephalography as well as electromyography), and has been proposed to be useful for the detection of pain among patients who are unable to communicate verbally. This review aimed to clarify whether the bispectral index is an appropriate tool to assess pain in the intensive care unit.

BACKGROUND:

Pain assessment is an immense challenge for clinicians, especially in the context of the intensive care unit, where the patient is often unable to communicate verbally. Several methods of pain assessment have been proposed to assess pain in this environment. These include both behavioural observation scales and evaluation of physiological measurements such as heart rate and blood pressure. Although numerous validation studies pertaining to behavioural observation scales have been published, several limitations associated with using these measures for pain assessment remain. Over the past few years, researchers have been interested in the use of the bispectral index monitoring system as a proxy for the evaluation of encephalography readings to assess the level of anesthesia and, potentially, analgesia.

OBJECTIVES:

To synthesize the main studies exploring the use of the bispectral index monitoring system for pain assessment, to guide future research in adults under sedation in the intensive care unit.

METHOD:

The EMBASE, Medline, CINAHL and PsycINFO databases were searched for studies published between 1996 and 2013 that evaluated the use of the bispectral index in assessing pain.

RESULTS:

Most studies conclude that nociceptive stimulation causes a significant increase in the bispectral index and revealed the importance of controlling certain confounding variables such as the level of sedation.

DISCUSSION:

Further studies are needed to clearly demonstrate the relationship between nociceptive stimuli and the bispectral index, as well as the specificity of the bispectral index in detecting pain.

An evaluation of the validity and potential utility of facial electromyelogram Responsiveness Index for sedation monitoring in critically ill patients

PURPOSE

The purpose of this study is to explore the validity of a novel sedation monitoring technology based on facial electromyelography (EMG) in sedated critically ill patients.

MATERIALS AND METHODS

The Responsiveness Index (RI) integrates the preceding 60 minutes of facial EMG data. An existing data set was used to derive traffic light cut-offs for low (red), intermediate (amber), and higher (green) states of patient arousal. The validity of these was prospectively evaluated in 30 sedated critically ill patients against hourly Richmond Agitation Sedation Scale (RASS) assessments with concealment of RI data from clinical staff.

RESULTS

With derivation data, an RI less than or equal to 35 had best discrimination for a Ramsay score of 5/6 (sensitivity, 90%; specificity, 79%). For traffic lights, we chose RI less than or equal to 20 as red, 20 to 40 as amber, and more than 40 as green. In the prospective study, RI values were red/amber for 76% of RASS -5/-4 assessments, but RI varied dynamically over time in many patients, and discordance with RASS may have resulted from the use of 1 hour of data for RI calculations. We also noted that red/amber values resulted from sleep, encephalopathy, and low levels of stimulation.

CONCLUSIONS

Responsiveness Index is not directly comparable with clinical sedation scores but is a potential continuous alert to possible deep sedation in critically ill patients.

Appropriateness and reliability testing of the modified Richmond Agitation-Sedation Scale in Spanish patients with advanced cancer

CONTEXT

A tool to quantify agitation severity and sedation level in patients with advanced cancer is needed.

OBJECTIVES

To test the appropriateness and reliability of the Richmond Agitation-Sedation Scale (RASS) in Spanish patients with advanced cancer.

METHODS

The original RASS was translated into Spanish according to the standard guidelines. Face validity was assessed by members of the palliative care team, and interrater reliability was assessed, using a weighted kappa, from observations of patients admitted to the palliative care unit. The association between scores of the RASS, Ramsay Sedation Scale, and Glasgow Coma Scale was evaluated using Spearman's ρ.

RESULTS

Three hundred twenty-two observations were performed in 156 patients: 116 observations were performed for delirious patients, 76 observations for sedated patients, and 130 observations for patients admitted for other symptom control. The weighted kappa values were practically equal to or greater than 0.90 between nurses and nurses and physicians. The agreement level between observers for each RASS score was roughly 90%. The correlation between the RASS and the Ramsay and Glasgow Scale values was analyzed for 196 observations recorded in 80 patients. The sedation scale of the RASS had a strong correlation with both the Ramsay (Spearman's ρ, -0.89; P < 0.001) and the Glasgow Coma Scales (Spearman's ρ, 0.85; P < 0.001).

CONCLUSION

These data support the use of the RASS in Spanish patients with advanced cancer.

Clinical practice guidelines for the management of pain, agitation, and delirium in adult patients in the intensive care unit

OBJECTIVE

To revise the "Clinical Practice Guidelines for the Sustained Use of Sedatives and Analgesics in the Critically Ill Adult" published in Critical Care Medicine in 2002.

METHODS

The American College of Critical Care Medicine assembled a 20-person, multidisciplinary, multi-institutional task force with expertise in guideline development, pain, agitation and sedation, delirium management, and associated outcomes in adult critically ill patients. The task force, divided into four subcommittees, collaborated over 6 yr in person, via teleconferences, and via electronic communication. Subcommittees were responsible for developing relevant clinical questions, using the Grading of Recommendations Assessment, Development and Evaluation method (http://www.gradeworkinggroup.org) to review, evaluate, and summarize the literature, and to develop clinical statements (descriptive) and recommendations (actionable). With the help of a professional librarian and Refworks database software, they developed a Web-based electronic database of over 19,000 references extracted from eight clinical search engines, related to pain and analgesia, agitation and sedation, delirium, and related clinical outcomes in adult ICU patients. The group also used psychometric analyses to evaluate and compare pain, agitation/sedation, and delirium assessment tools. All task force members were allowed to review the literature supporting each statement and recommendation and provided feedback to the subcommittees. Group consensus was achieved for all statements and recommendations using the nominal group technique and the modified Delphi method, with anonymous voting by all task force members using E-Survey (http://www.esurvey.com). All voting was completed in December 2010. Relevant studies published after this date and prior to publication of these guidelines were referenced in the text. The quality of evidence for each statement and recommendation was ranked as high (A), moderate (B), or low/very low (C). The strength of recommendations was ranked as strong (1) or weak (2), and either in favor of (+) or against (-) an intervention. A strong recommendation (either for or against) indicated that the intervention's desirable effects either clearly outweighed its undesirable effects (risks, burdens, and costs) or it did not. For all strong recommendations, the phrase "We recommend …" is used throughout. A weak recommendation, either for or against an intervention, indicated that the trade-off between desirable and undesirable effects was less clear. For all weak recommendations, the phrase "We suggest …" is used throughout. In the absence of sufficient evidence, or when group consensus could not be achieved, no recommendation (0) was made. Consensus based on expert opinion was not used as a substitute for a lack of evidence. A consistent method for addressing potential conflict of interest was followed if task force members were coauthors of related research. The development of this guideline was independent of any industry funding.

CONCLUSION

These guidelines provide a roadmap for developing integrated, evidence-based, and patient-centered protocols for preventing and treating pain, agitation, and delirium in critically ill patients.

Prognostic evaluation of bispectral index in patients following cardiopulmonary resuscitation

The aim of this study was to evaluate the prognosis of patients following cardiopulmonary resuscitation in an intensive care unit (ICU) using bispectral index (BIS) monitoring. The study was a prospective comparative study performed at the academic department of an ICU. A total of 33 adults who received cardiopulmonary resuscitation were enrolled and divided into the surviving and non-surviving groups according to their 7-day survival status. During their stay in the ICU, the BIS and arterial oxygen saturation (SaO₂) levels of all the patients were continuously monitored. The neurological condition of the patients was measured according to the Glasgow coma scale (GCS). Acute physiological and chronic diseases were measured according to the acute physiology and chronic health evaluation II (APACHE II). SaO₂ was monitored in all patients. The jugular bulb venous oxygen saturation (SjO₂) levels were continuously monitored in 23 patients and the difference between the SaO₂ and SjO₂ values was used to indicate oxygen metabolism in the brain. The variables in the present study were compared between the 2 groups. The correlations between BIS values and GCS or APACHE II scores were analyzed. The BIS values were significantly higher in the surviving group than in the non-surviving group (P<0.01). The difference between the SaO₂ and SjO₂ was significant (P<0.01). There was a positive correlation between BIS values and GCS scores (r=0.821, P<0.01) and between BIS values and APACHE II scores (r=0.434, P<0.05). BIS values may be used to predict the post-resuscitative outcome of patients following cardiopulmonary resuscitation.

Sedation for critically ill or injured adults in the intensive care unit: a shifting paradigm

As most critically ill or injured patients will require some degree of sedation, the goal of this paper was to comprehensively review the literature associated with use of sedative agents in the intensive care unit (ICU). The first and selected latter portions of this article present a narrative overview of the shifting paradigm in ICU sedation practices, indications for uninterrupted or prolonged ICU sedation, and the pharmacology of sedative agents. In the second portion, we conducted a structured, although not entirely systematic, review of the available evidence associated with use of alternative sedative agents in critically ill or injured adults. Data sources for this review were derived by searching OVID MEDLINE and PubMed from their first available date until May 2012 for relevant randomized controlled trials (RCTs), systematic reviews and/or meta-analyses and economic evaluations. Advances in the technology of mechanical ventilation have permitted clinicians to limit the use of sedation among the critically ill through daily sedative interruptions or other means. These practices have been reported to result in improved mortality, a decreased length of ICU and hospital stay and a lower risk of drug-associated delirium. However, in some cases, prolonged or uninterrupted sedation may still be indicated, such as when patients develop intracranial hypertension following traumatic brain injury. The pharmacokinetics of sedative agents have clinical importance and may be altered by critical illness or injury, co-morbid conditions and/or drug-drug interactions. Although use of validated sedation scales to monitor depth of sedation is likely to reduce adverse events, they have no utility for patients receiving neuromuscular receptor blocking agents. Depth of sedation monitoring devices such as the Bispectral Index (BIS©) also have limitations. Among existing RCTs, no sedative agent has been reported to improve the risk of mortality among the critically ill or injured. Moreover, although propofol may be associated with a shorter time to tracheal extubation and recovery from sedation than midazolam, the risk of hypertriglyceridaemia and hypotension is higher with propofol. Despite dexmedetomidine being linked with a lower risk of drug-associated delirium than alternative sedative agents, this drug increases risk of bradycardia and hypotension. Among adults with severe traumatic brain injury, there are insufficient data to suggest that any single sedative agent decreases the risk of subsequent poor neurological outcomes or mortality. The lack of examination of confounders, including the type of healthcare system in which the investigation was conducted, is a major limitation of existing pharmacoeconomic analyses, which likely limits generalizability of their results.

Assessment of pain in sedated and mechanically ventilated patients: an observational study

BACKGROUND

Critically ill patients often undergo unpleasant procedures. We quantified the effects of an unpleasant stimulus on physiological and behavioral parameters and evaluated how they are modified by sedation and analgesia.

METHODS

A 6-month study in the 30-bed intensive care unit (ICU) of a university hospital examined 21 sedated patients from various diagnostic groups. Hemodynamic and respiratory parameters, pupil size, facial expression, muscle tone, body movement, and the Richmond Agitation-Sedation Scale (RASS) score were measured before and during intratracheal suctioning, first in sedated patients, after sedation was stopped, and after an opioid bolus.

RESULTS

Before intratracheal suctioning, patients had RASS scores of -1.8 ± 1.2 (mean ± standard deviation; sedation), -0.6 ± 1.7 (sedation stop), and -0.9 ± 1.4 (analgesia) (P = 0.014). Intratracheal suctioning significantly increased RASS during both sedation (to -0.6 ± 1.7) and sedation stop (to 1.0 ± 1.5) (both P < 0.01), but not during analgesia. Systolic blood pressure increased during sedation (by 9 ± 10 mmHg), during sedation stop (by 15 ± 17 mmHg) and during analgesia (by 9 ± 4 mmHg; all P < 0.01), but diastolic pressure only during sedation and sedation stop (both P < 0.01). Facial expression, body movement, and muscle tone changed significantly during the episodes of intratracheal suctioning. Heart rate, tidal volume, and pupil size remained stable under all conditions.

CONCLUSIONS

Intratracheal suctioning evoked significant changes in some physiological and behavioral parameters. Some physiological changes were suppressed by analgesia, but at our ICU's standard doses, neither analgesia nor sedation attenuated changes in behavioral parameters at the intensity tested.

Performance of the A-line Autoregressive Index (AAI) and of the Bispectral Index (BIS) at assessing depth of short-term sedation following cardiac surgery

This study evaluated the correlation and agreement between the Bispectral Index (BIS) or A-line Autoregressive Index (AAI) and a clinical scoring system, the Ramsay Sedation Scale (RSS), in 40 patients after elective cardiac surgery and admission to the intensive care unit. All patients received sedation with propofol according to the study protocol. BIS, AAI and RSS were documented at two different levels of sedation: deep sedation RSS 4 - 6; and slight sedation/extubation RSS 2 - 3. Both the BIS and AAI agreed well with the RSS (eta-coefficients of 0.902 and 0.836, respectively, for mean overall RSS stages). The systems agreed well among each other (overall intra-class correlations of 0.670 for consistency and 0.676 for absolute agreement). There was significant discrimination between RSS 2 - 3 and RSS 4 - 6 with BIS and AAI (BIS mean difference of 24.73, 95% confidence intervals [CI] 21.08 - 28.37; AAI mean difference of 20.90, 95% CI 14.64 - 27.16). In conclusion, BIS and AAI correlated well with RSS overall and also at different levels of sedation.

Frontal EEG for intensive care unit sedation: treating numbers or patients?

In this issue of Critical Care, Dr Haenggi and co-workers present a study evaluating bispectral index (BIS), state entropy (SE) and response entropy in 44 patients sedated in the intensive care unit (ICU). As in recent studies attempting to correlate frontal electroencephalogram (EEG) measurements with clinical evaluations of sedative efficacy, there is considerable overlap in numerical EEG values and different clinical levels of sedation. This precludes the use of these monitors for monitoring or titrating sedation in the critically ill. Despite many attempts, no study has yet presented data showing improved outcome with the use of EEG monitors in ICU sedation. Meanwhile, clinical sedation protocols have emerged, improving important endpoints in critically ill patients needing sedation. A major underlying problem in applying EEG monitors in the ICU is that they have been developed for measuring anesthetic depth and the related risk of recall, rather than the acknowledged endpoints of sedation, namely reduction of anxiety and discomfort. Until an 'objective' monitor is developed to measure the degree of such symptoms, physicians should continue treating patients and not numbers.