Anesthesia Geriatric Evaluation (AGE): A Care-Ethical Perspective of a Multi-Disciplinary Approach for Tailored Preoperative Interventions

Background: Frailty is considered to be an important risk factor for mortality in hospitalized patients. This study evaluates a preoperative frailty-screening tool called Anesthesia Geriatric Evaluation (AGE). Research into the concept of frailty, with a focus on multidisciplinary team meetings, may provide further insight for health care professionals in the understanding of frailty in everyday care situations. Methods: The research method chosen for this research is QUAGOL: Qualitative Analysis Guide of Leuven, which aims to reconstruct the story of the participants on a theoretical level and analyze the concepts found. Results: The following themes illustrate the analyzed concepts found: competence, resilience, sharing responsibility, broad frame of reference, obligation, and significance. Conclusion: AGE seems to create more awareness among health care professionals about frailty and tries to involve patients in their care process by making them aware of their abilities, motivation, and involving them in decisions to be made. This study shows that a shared decision-making process for surgical patients is often difficult to accomplish since AGE is still a paternalistic process of a multidisciplinary team with a medical perspective.

Peripheral blood gene expression profiles linked to monoamine metabolite levels in cerebrospinal fluid

The blood-brain barrier separates circulating blood from the central nervous system (CNS). The scope of this barrier is not fully understood which limits our ability to relate biological measurements from peripheral to central phenotypes. For example, it is unknown to what extent gene expression levels in peripheral blood are reflective of CNS metabolism. In this study, we examine links between central monoamine metabolite levels and whole-blood gene expression to better understand the connection between peripheral systems and the CNS. To that end, we correlated the prime monoamine metabolites in cerebrospinal fluid (CSF) with whole-genome gene expression microarray data from blood (N=240 human subjects). We additionally applied gene-enrichment analysis and weighted gene co-expression network analyses (WGCNA) to identify modules of co-expressed genes in blood that may be involved with monoamine metabolite levels in CSF. Transcript levels of two genes were significantly associated with CSF serotonin metabolite levels after Bonferroni correction for multiple testing: THAP7 (P=2.8 × 10^-8, β=0.08) and DDX6 (P=2.9 × 10^-7, β=0.07). Differentially expressed genes were significantly enriched for genes expressed in the brain tissue (P=6.0 × 10^-52). WGCNA revealed significant correlations between serotonin metabolism and hub genes with known functions in serotonin metabolism, for example, HTR2A and COMT. We conclude that gene expression levels in whole blood are associated with monoamine metabolite levels in the human CSF. Our results, including the strong enrichment of brain-expressed genes, illustrate that gene expression profiles in peripheral blood can be relevant for quantitative metabolic phenotypes in the CNS.

An integrated population pharmacokinetic meta-analysis of propofol in morbidly obese and nonobese adults, adolescents, and children

This study describes a population pharmacokinetic meta-analysis of propofol to characterize the influence of body size measures and age in morbidly obese and nonobese adults, adolescents, and children. Sixty morbidly obese and nonobese adult patients (55-167 kg; 21-79 years) and 34 morbidly obese and nonobese adolescents and children (37-184 kg; 9-20 years) were included. The results show that clearance increased with total body weight in an allometric function while age was found to influence clearance in a bilinear fashion with two distinct slopes, reflecting an initial increase and subsequent decrease as a result of aging. Using these two functions, the influence of both (over)weight and age on propofol clearance was well characterized, which may provide a basis for dosing across this diverse group of patients.CPT: Pharmacometrics & Systems Pharmacology (2013) 2, e73; doi:10.1038/psp.2013.47; advance online publication 11 September 2013.

Aminotransferase Levels in Relation to Short-Term use of Acetaminophen Four Grams Daily in Postoperative Cardiothoracic Patients in the Intensive Care Unit

A volunteer study suggested that taking paracetamol 4 g daily could result in elevated alanine aminotransferase plasma levels in a substantial proportion of healthy volunteers. The safety of this dose of paracetamol for acute postoperative pain remains controversial. This study aimed to examine the incidence of alanine aminotransferase elevations after short-term use of paracetamol 4 g daily, as part of the standard pain management protocol, for 93 consecutive patients after cardiothoracic surgery. Alanine aminotransferase levels and other liver function tests were measured preoperatively as baseline and once daily after surgery during the intensive care unit stay. Preoperative alanine aminotransferase levels of more than one time the upper limit of normal (ULN, >40 U/l) was observed in 11% (n=10) of the patients but none of these baseline alanine aminotransferase levels exceeded three times the ULN (>3×ULN). The average daily dose of paracetamol administered was 50 mg/kg (SD=16) after surgery. Postoperative alanine aminotransferase levels of >1×ULN was observed in 17% (n=16), and 4% (n=4) exceeded >3×ULN. The other liver function tests of the latter four patients, including aspartate aminotransferase (range 173 to 5590 U/l), γ-glutamyltransferase (range 56 to 103 U/l), lactate dehydrogenase (range 376 to 3518 U/l) and the International Normalised Ratio (range 2.0 to 6.6), were all abnormal. These four patients all had right ventricular failure or cardiogenic shock during the postoperative period which could explain the significant rises in alanine aminotransferase after surgery. In conclusion, the incidence of significant alanine aminotransferase elevations after using daily paracetamol as an analgesic agent for cardiac surgery, at a dose of 4 g per day, was low and mostly due to complications after surgery. Our results, albeit still very limited, provided some reassurance about the safety of paracetamol 4 g daily, as a supplementary analgesic agent for adult patients undergoing cardiac surgery.

Maintenance of anesthesia in morbidly obese patients using propofol with continuous BIS-monitoring: a comparison of propofol-remifentanil and propofol-epidural anesthesia

PURPOSE

Aim of this study was to evaluate maintenance of anesthesia using propofol with continuous Bispectral Index (BIS)-monitoring in morbidly obese patients receiving propofol-remifentanil and propofol-epidural anesthesia.

METHODS

In the first group in ten morbidly obese patients receiving remifentanil analgesia, a propofol infusion was started at 10 mg/kg/hr and modified by aiming at BIS values between 40-60 together with predefined hemodynamic parameters. In the second group, the propofol dose resulting from the first group was prospectively evaluated in a matched cohort of six morbidly obese patients receiving propofol-epidural analgesia aiming for the same BIS and hemodynamic parameters. In both groups, propofol concentration and infusion rates, BIS and hemodynamic values were collected.

RESULTS

In the propofol-remifentanil group (Body Mass Index (BMI) 39-60 kg/m2), the mean propofol infusion rate that corresponded to the predefined BIS and hemodynamic parameters was 4.8 mg/kg/hr (SD 1.5). On this basis, a maintenance dose of 5 mg/kg/hr was started in the propofol-epidural group (BMI 38-58 kg/m2). In this second group, the mean propofol infusion rate that corresponded to predefined BIS and hemodynamic parameters was 5.0 mg/kg/hr (SD 0.6). Between the two groups, there was no difference in the propofol concentration-BIS relation.

CONCLUSION

Using both BIS and hemodynamic parameters as an endpoint, a maintenance dose of propofol of 4-6 mg/kg/hr is proposed for maintenance of anesthesia in morbidly obese patients undergoing bariatric surgery either in combination with remifentanil or epidural analgesia. There was no difference in propofol concentration-BIS relation in morbidly obese patients receiving propofol-remifentanil or propofol-epidural anesthesia.