Monitoring nociception and awareness during palliative sedation: A systematic review

BACKGROUND

Providing unawareness and pain relief are core elements of palliative sedation. In addition to clinical scales, nociception and electroencephalogram-based depth of sedation monitoring are used to assess the level of consciousness and analgesia during sedation in intensive care units and during procedures.

AIM

To determine whether reported devices impact the outcomes of palliative sedation.

DESIGN

Systematic review and narrative synthesis of research published between January 2000 and December 2020.

DATA SOURCES

Embase, Google Scholar, PubMed, CENTRAL, and the Cochrane Library. All reports describing the use of any monitoring device to assess the level of consciousness or analgesia during palliative sedation were screened for inclusion. Data concerning safety and efficacy were extracted. Patient comfort was the primary outcome of interest. Articles reporting sedation but that did not meet guidelines of the European Association for Palliative Care were excluded.

RESULTS

Six reports of five studies were identified. Four of these were case series and two were case reports. Together, these six reports involved a total of 67 sedated adults. Methodological quality was assessed fair to good. Medication regimens were adjusted to bispectral index monitoring values in two studies, which found poor correlation between monitoring values and observational scores. In another study, high nociception index values, representing absence of pain, were used to detect opioid overdosing. Relatives and caregivers found the procedures feasible and acceptable.

Reflections on palliative sedation

'Palliation sedation' is a widely used term to describe the intentional administration of sedatives to reduce a dying person's consciousness to relieve intolerable suffering from refractory symptoms. Research studies generally focus on either 'continuous sedation until death' or 'continuous deep sedation'. It is not always clear whether instances of secondary sedation (i.e. caused by specific symptom management) have been excluded. Continuous deep sedation is controversial because it ends a person's 'biographical life' (the ability to interact meaningfully with other people) and shortens 'biological life'. Ethically, continuous deep sedation is an exceptional last resort measure. Studies suggest that continuous deep sedation has become 'normalized' in some countries and some palliative care services. Of concern is the dissonance between guidelines and practice. At the extreme, there are reports of continuous deep sedation which are best described as non-voluntary (unrequested) euthanasia. Other major concerns relate to its use for solely non-physical (existential) reasons, the under-diagnosis of delirium and its mistreatment, and not appreciating that unresponsiveness is not the same as unconsciousness (unawareness). Ideally, a multiprofessional palliative care team should be involved before proceeding to continuous deep sedation. Good palliative care greatly reduces the need for continuous deep sedation.

The Practice of Continuous Palliative Sedation in Long-Term Care for Frail Patients with Existential Suffering

Some guidelines and recommendations identify existential suffering as a potential refractory symptom for which continuous palliative sedation (CPS) can be administered under certain conditions. However, there has been little research on the characteristics of patients with existential suffering treated with CPS and the degree to which the preconditions are fulfilled. The aim of this study was to provide insight into this specific indication for CPS. Questionnaires were sent to nursing home physicians in the Netherlands, who described 314 patients. Existential suffering was a refractory symptom in 83 of the patients. For most of the patients with refractory existential suffering, other refractory symptoms were also reported, and life expectancy was seven days or less; informed consent for initiating CPS had been obtained in all cases. Consultation and intermittent sedation before the start of CPS were far less frequently reported than one would expect based on the guidelines. Multivariate analysis showed that being male, having previously requested euthanasia, having a nervous system disease, or having an other diagnosis were positively correlated with the administration of CPS for existential suffering. We conclude that more attention should be paid to the suggested preconditions and to the presence of existential suffering in male patients or patients with a nervous system disease.

Population pharmacodynamic modelling of midazolam induced sedation in terminally ill adult patients

Aims

Midazolam is the drug of choice for palliative sedation and is titrated to achieve the desired level of sedation. A previous pharmacokinetic (PK) study showed that variability between patients could be partly explained by renal function and inflammatory status. The goal of this study was to combine this PK information with pharmacodynamic (PD) data, to evaluate the variability in response to midazolam and to find clinically relevant covariates that may predict PD response.

Method

A population PD analysis using nonlinear mixed effect models was performed with data from 43 terminally ill patients. PK profiles were predicted by a previously described PK model and depth of sedation was measured using the Ramsay sedation score. Patient and disease characteristics were evaluated as possible covariates. The final model was evaluated using a visual predictive check.

Results

The effect of midazolam on the sedation level was best described by a differential odds model including a baseline probability, Emax model and interindividual variability on the overall effect. The EC50 value was 68.7 μg l^–1 for a Ramsay score of 3–5 and 117.1 μg l^–1 for a Ramsay score of 6. Comedication with haloperidol was the only significant covariate. The visual predictive check of the final model showed good model predictability.

Conclusion

We were able to describe the clinical response to midazolam accurately. As expected, there was large variability in response to midazolam. The use of haloperidol was associated with a lower probability of sedation. This may be a result of confounding by indication, as haloperidol was used to treat delirium, and deliria has been linked to a more difficult sedation procedure.

The impact of the inpatient practice of continuous deep sedation until death on healthcare professionals' emotional well-being: a systematic review

Background

The practice of continuous deep sedation is a challenging clinical intervention with demanding clinical and ethical decision-making. Though current research indicates that healthcare professionals’ involvement in such decisions is associated with emotional stress, little is known about sedation-related emotional burden. This study aims to systematically review the evidence on the impact of the inpatient practice of continuous deep sedation until death on healthcare professionals’ emotional well-being.

Methods

A systematic review of literature published between January 1990 and October 2016 was performed following a predefined protocol. MEDLINE, EMBASE, PubMed, Cochrane Library, CINAHL, Scopus, and PsycINFO were searched using search terms within “end-of-life care”, “sedation”, and “emotional well-being”. Dissertations and reference lists were screened by hand. Two independent reviewers conducted study selection, data extraction and quality assessment. We abstracted measures of psychological outcomes, which were related to the practice of continuous deep sedation until death, including emotional well-being, stress and exhaustion. We used the GRADE approach to rate the quality of evidence.

Results

Three studies remained out of 528 publications identified. A total of 3′900 healthcare professionals (82% nurses, 18% physicians) from Japan (n = 3384) and the Netherlands (n = 16) were included. The prevalence of sedation-related burden in nurses varied from 11 to 26%, depending on outcome measure. Physicians showed medium levels of emotional exhaustion and low levels of depersonalization. Common clinical concerns contributing to professionals’ burden were diagnosing refractory symptoms and sedation in the context of possibly life-shortening decisions. Non-clinical challenges included conflicting wishes between patients and families, disagreements within the care team, and insufficient professionals’ skills and coping. Due to the limited results and heterogeneity in outcome measure, the GRADE ratings for the quality of evidence were low.

Conclusions

Current evidence does not suggest that practicing continuous deep sedation is generally associated with lower emotional well-being of healthcare professionals. Higher emotional burden seems more likely when professionals struggled with clinical and ethical justifications for continuous deep sedation. This appeared to be in part a function of clinical experience. Further research is needed to strengthen this evidence, as it is likely that additional studies will change the current evidence base.