Evaluation of the palliative symptom burden score (PSBS) in a specialised palliative care unit of a university medical centre - a longitudinal study.

BACKGROUND: The implementation of standardised, valid and reliable measurements in palliative care is subject to practical and methodological challenges. One aspect of ongoing discussion is the value of systematic proxy-based assessment of symptom burden in palliative care. In 2011, an expert-developed proxy-based instrument for the assessment of symptom burden in palliative patients, the Palliative Symptom Burden Score (PSBS), was implemented at the Specialised Palliative Care Unit of the University Medical Centre in Dusseldorf, Germany. The present study investigated its feasibility, acceptance and psychometric properties. METHODS: The PSBS was rated by nursing staff three times a day over 5 years (N = 820 patients). Feasibility and nurses' acceptance of PSBS were analysed. Structural validity was investigated by principal component analysis. Construct validity was examined via cross-validation with the Hospice and Palliative Care Evaluation checklist. Discriminative validity of the PSBS was analysed by means of Kruskal-Wallis test of patients' performance score. Reliability of the PSBS was evaluated by internal consistency analysis, test-retest and split-half-reliability. Inter-rater reliability was investigated by observer agreement of nurses' ratings of symptom burden within a day. Sensitivity to change was analysed by Wilcoxon test with repeated measures of the PSBS before and after palliative complex treatment. RESULTS: A high degree of acceptance and the feasibility of a high-frequency proxy-based symptom burden assessment approach were demonstrated. There were low rates of missing values and no indications of the adoption of prior ratings. PSBS in its present form demonstrates good structural and construct validity (rs = .27-.79, p's < .001) and high sensitivity to changes in symptom burden (p's < .01, except sweating), but unsatisfactory reliability (α = .41-.67; test-retest: rs = .30-.88; p's < .001; split-half: rs = .69; p < .001; inter-rater: n.s.). CONCLUSIONS: The study presents a framework for the post hoc validation of an already existing documentation tool in palliative care. This study supports the notion that PSBS might not be reflective of an overall construct and will therefore require further development and critical comparison to other already established symptom burden instruments in palliative care.

In vivo desflurane preconditioning evokes dynamic alterations of metabolic proteins in the heart--proteomic insights strengthen the link between bioenergetics and cardioprotection.

BACKGROUND: The cardioprotective effect of anaesthetic preconditioning as measured by reduction of ischaemia-reperfusion (I/R) injury is a well described phenomenon. However little is known about the impact on the myocardial proteome. We therefore investigated proteome dynamics at different experimental time points of a preconditioning protocol. METHODS: Using an in vivo rat model of desflurane-induced preconditioning (DES-PC) cardiac tissue proteomes were analysed by a gel-based comparative approach. Treatment-dependent protein alterations were assessed by intra-group comparisons. Proteins were identified by mass-spectrometry. RESULTS: A total of 40 protein spots were altered during the 30-minutes lasting preconditioning protocol. None of the proteins was differentially regulated consistently at all experimental time points. Interestingly, 1) the repeated administration of desflurane mostly accounted for proteome alterations during DES-PC, 2) the majority of altered protein species showed a decrease in abundance, 3) these changes primarily affected metabolic proteins involved in NADH/NAD(+) redox balance, calcium homeostasis and acidosis and 4) protein alterations were not exclusively due to expression changes but also represented modifications of specific protein isoforms. CONCLUSION: DES-PC evokes dynamic alterations in the cardiac proteome which substantiate a tight regulation of bioenergetic proteins. Unique protein modifications may play a more important role in the preconditioning response.