Methodology used in studies reporting chronic kidney disease prevalence: a systematic literature review

Background Many publications report the prevalence of chronic kidney disease (CKD) in the general population. Comparisons across studies are hampered as CKD prevalence estimations are influenced by study population characteristics and laboratory methods. Methods For this systematic review, two researchers independently searched PubMed, MEDLINE and EMBASE to identify all original research articles that were published between 1 January 2003 and 1 November 2014 reporting the prevalence of CKD in the European adult general population. Data on study methodology and reporting of CKD prevalence results were independently extracted by two researchers. Results We identified 82 eligible publications and included 48 publications of individual studies for the data extraction. There was considerable variation in population sample selection. The majority of studies did not report the sampling frame used, and the response ranged from 10 to 87%. With regard to the assessment of kidney function, 67% used a Jaffe assay, whereas 13% used the enzymatic assay for creatinine determination. Isotope dilution mass spectrometry calibration was used in 29%. The CKD-EPI (52%) and MDRD (75%) equations were most often used to estimate glomerular filtration rate (GFR). CKD was defined as estimated GFR (eGFR) <60 mL/min/1.73 m2 in 92% of studies. Urinary markers of CKD were assessed in 60% of the studies. CKD prevalence was reported by sex and age strata in 54 and 50% of the studies, respectively. In publications with a primary objective of reporting CKD prevalence, 39% reported a 95% confidence interval. Conclusions The findings from this systematic review showed considerable variation in methods for sampling the general population and assessment of kidney function across studies reporting CKD prevalence. These results are utilized to provide recommendations to help optimize both the design and the reporting of future CKD prevalence studies, which will enhance comparability of study result

Effects of Glucocorticoids and Nonsteroidal Anti-inflammatory Drugs on Postoperative and Experimental Pain

Optimizing non-opioid pain relief postoperatively is necessary to spare opioids, reduce opioid related side effects, increase the quality of analgesia, facilitate postoperative recovery and hopefully prevent chronic postoperative pain. In the present thesis, Luis Romundstad and co-workers investigated the effect of adding paracetamol (propacetamol 2 g i.v.) to an NSAID (ketorolac 30 mg i.v.) on human experimental pain, and the effect of a glucocorticoid (methylprednisolone 125 mg i.v.) on hyperalgesia, rescue analgesic use, postoperative emesis and fatigue in human postoperative and experimental pain models. They compared methylprednisolone with placebo, an NSAID (ketorolac 30 mg and 60 mg i.v.), or a selective COX-2 inhibitor (parecoxib 40 mg i.v.). They also studied the prevalence of chronic postoperative pain and sensory changes and the effect of methylprednisolone and parecoxib on these variables. For the first time a glucocorticoid (methylprednisolone), and an NSAID (ketorolac), was shown to decrease secondary hyperalgesia, indicating a central anti-hyperalgesic effect of these drugs. Methylprednisolone and ketorolac increased the tolerance threshold for painful pressure, and adding paracetamol to ketorolac increased this tolerance further compared with ketorolac alone. Methylprednisolone and the active comparators ketorolac and parecoxib reduced acute postoperative pain. Methylprednisolone also reduced postoperative emesis, fatigue and persistent postoperative hyperesthesia. This thesis adds to the pool of evidence documenting that chronic postoperative pain and sensory changes are relatively common, with a 13% prevalence of pain and 46% hyperesthesia one year after breast augmentation surgery. According to the results in the present thesis we advocate the combination of NSAIDs and paracetamol, and/or a single, appropriate perioperative dose of a glucocorticoid in order to optimize postoperative pain relief

Timelines and rebleeds in patients admitted into neurosurgical care for aneurysmal subarachnoid haemorrhage

Abstract Background Mortality and morbidity of aneurysmal subarachnoid haemorrhage (aSAH) remain high, and prognosis is influenced by multiple non-modifiable factors such as aSAH severity. By analysing the chronology of aSAH management, we aim at identifying modifiable factors with emphasis on the occurrence of rebleeds in a setting with 24/7 surgical and endovascular availability of aneurysm repair and routine administration of tranexamic acid. Methods Retrospective analysis of institutional quality registry data of aSAH cases admitted into neurosurgical care during the time period 01 January 2013–31 December 2017. We registered time and mode of aneurysm repair, haemorrhage patterns, course of treatment, mortality and functional outcome. Rebleeding was scored along the entire timeline from ictus to discharge from the primary stay. Results We included 544 patients (368, 67.6% female), aged 58 ± 14 years (range 1–95 years). Aneurysm repair was performed in 486/544 (89.3%) patients at median 7.4 h after arrival and within 3, 6, 12 and 24 h in 26.8%, 44.7%, 73.0% and 96.1%, respectively. There were circadian variations in time to repair and in rebleeds. Rebleeding prior to aneurysm repair occurred in 9.7% and increased with aSAH severity and often in conjunction with patient relocations or interventions. Rebleeds occurred more often during surgical repair outside regular working hours, whereas rebleeds after repair (1.8%) were linked to endovascular repair. Conclusions The risk of rebleed is imminent throughout the entire timeline of aSAH management even with ultra-early aneurysm repair. Several modifiable factors can be linked to the occurrence of rebleeds and they should be identified and optimised within neurosurgical departments

Is simulation-based team training performed by personnel in accordance with the INACSL Standards of Best Practice: SimulationSM?—a qualitative interview study

Background Anesthesia personnel was among the first to implement simulation and team training including non-technical skills (NTS) in the field of healthcare. Within anesthesia practice, NTS are critically important in preventing harmful undesirable events. To our best knowledge, there has been little documentation of the extent to which anesthesia personnel uses recommended frameworks like the Standards of Best Practice: SimulationSM to guide simulation and thereby optimize learning. The aim of our study was to explore how anesthesia personnel in Norway conduct simulation-based team training (SBTT) with respect to outcomes and objectives, facilitation, debriefing, and participant evaluation. Methods Individual qualitative interviews with healthcare professionals, with experience and responsible for SBTT in anesthesia, from 51 Norwegian public hospitals were conducted from August 2016 to October 2017. A qualitative deductive content analysis was performed. Results The use of objectives and educated facilitators was common. All participants participated in debriefings, and almost all conducted evaluations, mainly formative. Preparedness, structure, and time available were pointed out as issues affecting SBTT. Conclusions Anesthesia personnel’s SBTT in this study met the International Nursing Association for Clinical Simulation and Learning (INACSL) Standard of Best Practice: SimulationSM framework to a certain extent with regard to objectives, facilitators’ education and skills, debriefing, and participant evaluation.publishedVersio

Validation of a new approach for distinguishing anesthetized from awake state in patients using directed transfer function applied to raw EEG

Abstract We test whether a measure based on the directed transfer function (DTF) calculated from short segments of electroencephalography (EEG) time-series can be used to monitor the state of the patients also during sevoflurane anesthesia as it can for patients undergoing propofol anesthesia. We collected and analyzed 25-channel EEG from 7 patients (3 females, ages 41–56 years) undergoing surgical anesthesia with sevoflurane, and quantified the sensor space directed connectivity for every 1-s epoch using DTF. The resulting connectivity parameters were compared to corresponding parameters from our previous study (n = 8, patients anesthetized with propofol and remifentanil, but otherwise using a similar protocol). Statistical comparisons between and within studies were done using permutation statistics, a data driven algorithm based on the DTF-parameters was employed to classify the epochs as coming from awake or anesthetized state. According to results of the permutation tests, DTF-parameter topographies were significantly different between the awake and anesthesia state at the group level. However, the topographies were not significantly different when comparing results computed from sevoflurane and propofol data, neither in the awake nor in anesthetized state. Optimizing the algorithm for simultaneously having high sensitivity and specificity in classification yielded an accuracy of 95.1% (SE = 0.96%), with sensitivity of 98.4% (SE = 0.80%) and specificity of 94.8% (SE = 0.10%). These findings indicate that the DTF changes in a similar manner when humans undergo general anesthesia caused by two distinct anesthetic agents with different molecular mechanisms of action

Distinguishing Anesthetized from Awake State in Patients: A New Approach Using One Second Segments of Raw EEG

Objective: The objective of this study was to test whether properties of 1-s segments of spontaneous scalp EEG activity can be used to automatically distinguish the awake state from the anesthetized state in patients undergoing general propofol anesthesia. Methods: Twenty five channel EEG was recorded from 10 patients undergoing general intravenous propofol anesthesia with remifentanil during anterior cervical discectomy and fusion. From this, we extracted properties of the EEG by applying the Directed Transfer Function (DTF) directly to every 1-s segment of the raw EEG signal. The extracted properties were used to develop a data-driven classification algorithm to categorize patients as “anesthetized” or “awake” for every 1-s segment of raw EEG. Results: The properties of the EEG signal were significantly different in the awake and anesthetized states for at least 8 of the 25 channels (p < 0.05, Bonferroni corrected Wilcoxon rank-sum tests). Using these differences, our algorithms achieved classification accuracies of 95.9%. Conclusion: Properties of the DTF calculated from 1-s segments of raw EEG can be used to reliably classify whether the patients undergoing general anesthesia with propofol and remifentanil were awake or anesthetized. Significance: This method may be useful for developing automatic real-time monitors of anesthesia

Increased signal diversity/complexity of spontaneous EEG, but not evoked EEG responses, in ketamine-induced psychedelic state in humans

Objective How and to what extent electrical brain activity is affected in pharmacologically altered states of consciousness, where it is mainly the phenomenological content rather than the level of consciousness that is altered, is not well understood. An example is the moderately psychedelic state caused by low doses of ketamine. Therefore, we investigated whether and how measures of evoked and spontaneous electroencephalographic (EEG) signal diversity are altered by sub-anaesthetic levels of ketamine compared to normal wakefulness, and how these measures relate to subjective assessments of consciousness. Methods High-density electroencephalography (EEG, 62 channels) was used to record spontaneous brain activity and responses evoked by transcranial magnetic stimulation (TMS) in 10 healthy volunteers before and after administration of sub-anaesthetic doses of ketamine in an open-label within-subject design. Evoked signal diversity was assessed using the perturbational complexity index (PCI), calculated from the global EEG responses to local TMS perturbations. Signal diversity of spontaneous EEG, with eyes open and eyes closed, was assessed by Lempel Ziv complexity (LZc), amplitude coalition entropy (ACE), and synchrony coalition entropy (SCE). Results Although no significant difference was found in the index of TMS-evoked complexity (PCI) between the sub-anaesthetic ketamine condition and normal wakefulness, all the three measures of spontaneous EEG signal diversity showed significantly increased values in the sub-anaesthetic ketamine condition. This increase in signal diversity also correlated with subjective assessment of altered states of consciousness. Moreover, spontaneous signal diversity was significantly higher when participants had eyes open compared to eyes closed, both during normal wakefulness and during influence of sub-anaesthetic ketamine doses. Conclusion The results suggest that PCI and spontaneous signal diversity may be complementary and potentially measure different aspects of consciousness. Thus, our results seem compatible with PCI being indicative of the brain’s ability to sustain consciousness, as indicated by previous research, while it is possible that spontaneous EEG signal diversity may be indicative of the complexity of conscious content. The observed sensitivity of the latter measures to visual input seems to support such an interpretation. Thus, sub-anaesthetic ketamine may increase the complexity of both the conscious content (experience) and the brain activity underlying it, while the level, degree, or general capacity of consciousness remains largely unaffected

Behavioral effects of sub-anesthetic ketamine in a go/no-go task

Background and aims While psychedelic agents are known to have powerful, but largely unexplained, effects on contents of consciousness, there is an increasing interest in the potential clinical usefulness of such drugs for therapy, and legalization is discussed in some countries. Thus, it is relevant to study the effects of psychedelic compounds not only on experience, but also on behavioral performance. Methods Seven healthy participants performed a motor response inhibition task before, during, and after sub-anesthetic doses of intravenously administered ketamine. The infusion rate was individually adjusted to produce noticeable subjective psychedelic effects. Results We observed no statistically significant impact of sub-anesthetic ketamine on reaction times, omission errors, or post error slowing, relative to the preceding drug-free condition. However, we did observe significant correlations between performance impairment and self-reported, subjective altered states of consciousness, specifically experience of “anxiety” and “complex imagery.” Conclusions Considering the limited number of participants and large variation in strength of self-reported experiences, further studies with wider ranges of ketamine doses and behavioral tasks are needed to determine the presence and strength of potential behavioral effects