Flush Test Research Articles

The 10Hz dynamic response of a fluid-filled pressure monitoring system is a novel alternative to the fast flush test and indicative of unacceptable systolic pressure overshoot.

The standard method for qualitatively evaluating the dynamic response is to see if the gain of the amplitude spectrum curve approaches 1 (input signal = output signal) over the frequency band of the blood pressure waveform. In a previous report, Watanabe reported that Gardner's natural frequency and damping coefficient, which are widely used as evaluation methods, do not reflect the dynamic response of the circuit. Therefore, new parameters for evaluating the dynamic response of pressure monitoring circuits were desired. In this study, arterial pressure catheters with length of 30, 60, 150, and 210 cm were prepared, and a blood pressure wave calibrator, two pressure monitors with analog output and a personal computer were used to analyze blood pressure monitoring circuits. All data collection and analytical processes were performed using step response analysis program. The gain at 10 Hz was close to 1 and the systolic blood pressure difference was small in the short circuits (30 cm, 60 cm), and the gain at 10 Hz was 1.3-1.5 in the 150 cm circuit and over 1.7 in the 210 cm circuit. The difference in systolic blood pressure increased in proportion to the length of the circuit. It could also be inferred that the gain at 10 Hz should be less than 1.2 to meet a clinically acceptable blood pressure difference. In conclusion, the gain at 10 Hz is sufficiently useful as an indicator to determine the correct systolic blood pressure.

#4977 ENDOTHELIAL DYSFUNCTION IN PATIENTS WITH COVID-19 DURING ANTIOXIDANT THERAPY

Abstract Background and Aims In connection with the coronavirus pandemic of 2020, there have been recent discussions about the role of endothelial function in the course and prognosis of the disease. Purpose of the study. study of endothelial function in patients who have had a coronavirus infection. Methods Under observation were 60 patients who underwent COVID-19 of moderate severity on the 14th day of therapy at the age of 57 to 67 years. Patients of the 1st group (30 patients), against the background of standard basic therapy, were prescribed L-carnitine at a dose of 5 g/day for 5 days, followed by a maintenance dose of 1 g/day for 5 days. Group II consisted of 30 patients who met the inclusion criteria for the study, were treated for COVID-19 and did not receive metabolic agents. The state of endothelial function was assessed according to Doppler sonography of the brachial artery using the D.S. Celemajer (1992) using a reactive flush test. Changes in the diameter of the right brachial artery were assessed using a 7.5-12 MHz linear transducer with a phase grating ultrasound system En Visor C Philips. The results of the study were processed statistically using Student's t test for paired and unpaired variables. Differences were considered significant at p<0.05. Results After analyzing the data of samples with RG in combination with blood flow velocity indicators, we noted that in response to an increase in blood flow velocity in the control group, the diameter of the brachial artery increased by almost 12%, in patients with COVID-19, the blood flow velocity increased significantly, and the diameter of the artery practically did not change. Thus, with an increase in the mechanical stimulus, i.e. blood flow velocity in patients with COVID-19 did not occur a commensurate increase in the diameter of the vessel. The results obtained indicate a pronounced dysfunction of the endothelium in patients with COVID-19, in particular, EDVD, the indicators of which were two times lower than the control values. Conclusions The inclusion of L-carnitine in the regimen of standard therapy for patients with COVID-19 significantly improves the values of EVR compared to the standard basic therapy.

Niacin Skin Flush Backs-From the Roots of the Test to Nowadays Hope.

The niacin skin flush test (NSFT) is a simple method used to assess the content of fatty acids in cell membranes and is a possible indicator of factors hidden behind various outcomes in patients. The purpose of this paper is to determine the potential usefulness of NSFT in mental disorder diagnostics along with the determination of factors that may affect its results. The authors reviewed articles from 1977 onwards, focusing on the history, variety of methodologies, influencing factors, and proposed mechanisms underlying its performance. Research indicated that NSFT could be applicable in early intervention, staging in psychiatry, and the search for new therapeutic methods and drugs based on the mechanisms of NSFT action. The NSFT can contribute to defining an individualized diet for patients and prevent the development of damaging disease effects at an early stage. There is promising evidence for supplementation with polyunsaturated fatty acids, which have a beneficial influence on the metabolic profile and are effective even in the subclinical phase of the disease. NSFT can contribute to the new classification of diseases and a better understanding of certain mental disorders' pathophysiology. However, there is a need to establish a validated method for assessing the NSFT results.

Additionally using transthoracic echocardiography during ultrasound-guided jugular central venous catheter placement and the odds of catheter misplacement in children: A before-and-after study.

Central venous catheter (CVC) misplacement is a major complication.1 To avoid CVC misplacement, real-time ultrasound (US) guidance is recommended for CVC placement in children.2, 3 Transthoracic echocardiography (TTE) can be additionally used to confirm correct CVC tip position.4, 5 Whether additionally using TTE during US-guided jugular CVC placement reduces the incidence of catheter misplacement remains scarcely described. We thus sought to test the hypothesis that additionally using TTE during US-guided jugular CVC placement reduces the odds of CVC misplacement in children. After approval by the ethics committee with waiver of informed consent, we performed a retrospective before-and-after study in children aged 0–6 years who received a jugular CVC during anesthetic induction for congenital heart disease surgery at the University Medical Center Hamburg-Eppendorf (Hamburg, Germany) between March 2015 and April 2020. In our institution, jugular CVCs in children having cardiac surgery are routinely placed using real-time US guidance since 2013. In October 2017, routine use of additional TTE during US-guided jugular CVC placement was implemented. In the 31-month “before period” (March 2015 to September 2017), anesthesiologists did not use TTE but chose the CVC insertion depth considering patient height (no-TTE-group). In the 31-month “after period” (October 2017 to April 2020), additional TTE (subcostal long-axis view) was routinely used during US-guided jugular CVC placement to confirm the correct position of the guidewire and the CVC tip (rapid saline flush test) (TTE-group) (Figure S1). During both study periods, chest x-ray was used to confirm correct CVC tip position after surgery. We categorized CVCs as misplaced when the CVC tip ended above the level of the superior vena cava in a noncentral vein or deep in the right atrium (Figure S2). We investigated the associations between CVC misplacement and TTE use by logistic regression for all patients including age as covariate—and separately for patients aged <1 year and 1–6 years. We report the odds ratios (OR) with 95% confidence intervals. We included 373 patients (156 no-TTE-group and 217 TTE-group) (Table S1). CVC misplacement occurred in 15/156 no-TTE-group patients (9.6%) and in 5/217 TTE-group patients (2.3%). The odds for CVC misplacement were 371% lower when TTE was used compared to when it was not used (p = .004, OR = 0.21 [0.067–0.57]) (Figure 1). Of all 373 patients, 229 (61%) were younger than 1 year. In these patients, CVC misplacement occurred in 8/76 no-TTE-group patients (11%) and in 4/153 TTE-group patients (2.6%). The odds for CVC misplacement were 319% lower when TTE was used (p = .023, OR = 0.24 [0.062–0.79]). Of all 373 patients, 144 (39%) were between 1 and 6 years old. In these patients, CVC misplacement occurred in 7/80 no-TTE-group patients (8.8%) and in 1/64 TTE-group patients (1.6%). The odds for CVC misplacement were 480% lower when TTE was used (p = .107, OR = 0.17 [0.0090–1.0]). In our study, additionally using TTE during US-guided jugular CVC placement in children reduced the odds for CVC misplacement by more than 300%—which obviously is clinically meaningful. In only about 1% of children, the subcostal long-axis view could not be obtained—and TTE could thus not be used to confirm the CVC tip position. In general, children provide an excellent acoustic window for TTE examination of the right atrium and the superior vena cava. Nevertheless, TTE requires technical skills and operator experience. Our results need to be interpreted in light of the inherent limitations of retrospective before-and-after studies. Additionally, we only included children with congenital heart disease, whose anatomy may differ from healthy children. However, as we excluded patients with irregular venous conformations, we assume that our findings can be transferred to pediatric patients in general. Additionally using TTE during US-guided jugular CVC placement reduces the odds of CVC misplacement in children aged 0–6 years. Clinicians should consider additionally using TTE during US-guided jugular CVC placement to increase patient safety. This work was supported solely from institutional and/or department sources. There are no conflicts of interest to declare. The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions. Supporting Information Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

DERMATOLOGICAL ISSUES IN PATIENT WITH PARKINSON’S DISEASE

To determine the incidence rate of seborrheic dermatitis, bullous pemphigoid, rosacea, and melanoma among the patients diagnosed with Parkinson's Disease. A cross-sectional, observational study. From 13th May 2020 to 13th April 2022 at Bahria International Hospital, Lahore, Pakistan. A total of 80 patients with confirmed Parkinson's disease were evaluated for skin disorders. Disease severity was confirmed through Hoehn Yahr staging criteria (H-Y stage). Skin characteristics and disease diagnosis was made through finding sebum production levels, hot/cold flush test, immunofluorescence, and biopsy evaluation for seborrheic dermatitis, rosacea, bullous pemphigoid, and melanoma, respectively. The test results were compared with the control subject. Chi2 and student t-test was used to find the significance of the results. Out of 80, 44 patients were positive for skin disorders. The incidence of seborrheic dermatitis was found in 31.2% of patients whereas rosacea, bullous pemphigoid, and melanoma were found in 15%, 6.2%, and 2.5% of patients, respectively. Skin disorders are highly prevalent among Parkinson’s disease patients than in the control population. The study invites further research in this area so that the quality of life of patients could be improved.

Increased Frequency of Dermatological Diseases in Parkinson's Patients

Objective: To determine the frequency of seborrheic dermatitis, bullous pemphigoid, rosacea, and melanomaamong the patients diagnosed with Parkinson Disease.Study Design: Cross sectional study.Place and Duration of Study: The study was carried out at Dermatology Department of Bakhtawar Amin Trustth th Teaching Hospital Multan from 13 May to 13 October 2020.Materials and Methods: A total of 80 patients of Parkinson disease were evaluated for skin disorders. Diseaseseverity was confirmed through Hoehn Yahr staging criteria (H-Y stage). Skin characteristics and diseasediagnosis was made through finding sebum production levels, hot/cold flush test, immunofluorescence andbiopsy evaluation for seborrheic dermatitis, rosacea, bullous pemphigoid, and melanoma, respectively. Thetest results were compared with control subject. Chi square test and student t-test were used to find thesignificance of results. P &lt; 0.05 will be statistically significant.Results: Out of 80, 44 patients were positive for skin disorders. The frequency of seborrheic dermatitis was31.2% and was quite high as compared to control group that was 25% whereas rosacea, bullous pemphigoidand melanoma was found in 15%, 6.2% and 2.5% patients and in control group they were 11.2%, 2.5% and 1.0%respectively. To detect the significant difference between quantitative variables of test and control group, chisquare was used and student t-test was used to compare the qualitative variables. P &lt; 0.05 will be statisticallysignificant.Conclusion: Skin disorders are highly prevalent among Parkinson's patients than control population.

Inflammation and JNK's Role in Niacin-GPR109A Diminished Flushed Effect in Microglial and Neuronal Cells With Relevance to Schizophrenia.

Schizophrenia is a neuropsychiatric illness with no single definitive aetiology, making its treatment difficult. Antipsychotics are not fully effective because they treat psychosis rather than the cognitive or negative symptoms. Antipsychotics fail to alleviate symptoms when patients enter the chronic stage of illness. Topical application of niacin showed diminished skin flush in the majority of patients with schizophrenia compared to the general population who showed flushing. The niacin skin flush test is useful for identifying patients with schizophrenia at their ultra-high-risk stage, and understanding this pathology may introduce an effective treatment. This review aims to understand the pathology behind the diminished skin flush response, while linking it back to neurons and microglia. First, it suggests that there are altered proteins in the GPR109A-COX-prostaglandin pathway, inflammatory imbalance, and kinase signalling pathway, c-Jun N-terminal kinase (JNK), which are associated with diminished flush. Second, genes from the GPR109A-COX-prostaglandin pathway were matched against the 128-loci genome wide association study (GWAS) for schizophrenia using GeneCards, suggesting that G-coupled receptor-109A (GPR109A) may have a genetic mutation, resulting in diminished flush. This review also suggests that there may be increased pro-inflammatory mediators in the GPR109A-COX-prostaglandin pathway, which contributes to the diminished flush pathology. Increased levels of pro-inflammatory markers may induce microglial-activated neuronal death. Lastly, this review explores the role of JNK on pro-inflammatory mediators, proteins in the GPR109A-COX-prostaglandin pathway, microglial activation, and neuronal death. Inhibiting JNK may reverse the changes observed in the diminished flush response, which might make it a good therapeutic target.

Accuracy of Niacin Skin Flush Test for Diagnosing Schizophrenia

Objectives: This study aims to investigate niacin sensitivity in schizophrenia patients compared to healthy people and examine the accuracy of niacin skin flush test in diagnosing schizophrenia. Methods: This diagnostic study was conducted in 2018 in Zanjan, Iran. Three niacin concentrations (0.001 M, 0.01 M, and 0.1 M) was first applied topically to the skin of 36 schizophrenia patients and 33 healthy controls. Flush responses were evaluated at 10 and 15 min after application. Sensitivity, specificity, Positive Predictive Value (PPV), and Negative Predictive Value (NPV) of the test were measured for each niacin concentration and evaluation time. Results: At 10 min, the highest test accuracy was reported when 0.001 M niacin solution was used (Sensitivity=94%, specificity=50%, PPV= 51%, and NPV= 94%). At 15 min, the highest test accuracy was observed at 0.01 concentration (Sensitivity=52%, specificity=92%, PPV=79%, and NPV=77%). Conclusion: Flush responses to niacin is more impaired in patients with schizophrenia. Therefore, niacin can be considered as a biological marker of schizophrenia and can be used for its diagnosis.

SKINREMS-A New Method for Assessment of the Niacin Skin Flush Test Response in Schizophrenia.

Schizophrenia has been considered a disorder linked with faulty lipid homeostasis, and the proposed tool for assessment of these disruptions is the niacin skin flush test. The aims of the study were: 1. Create a new tool to analyze results of the niacin skin flush test more precisely and objectively. 2. Verify the utility of a self-created tool for differentiating between schizophrenia (SZ; n = 56), bipolar disorder (BD; n = 29) and healthy control (HC; n = 45) individuals. The proposed developed method, based on the Skin Reaction Measurement Computer System (SKINREMS), allows one to evaluate the response to the niacin skin flush test quickly and objectively. SKINREMS showed good accuracy in discriminating SZ from BD (with sensitivity 91% and specificity 72%), and SZ from HC (71% and 66%, respectively), and sufficient but not excellent accuracy in discriminating BD from HC (55% and 54%, respectively). The pathophysiological pathways and features shared by schizophrenia and bipolar disorder may be the reason for difficulties in fully discriminating between these two mental disorders using the niacin challenge test. The management of disruptions in the phospholipid metabolism and the inflammatory process could potentially become an individualized form of therapy in a subgroup of psychiatric patients.

Circuit and Methodology for Testing Small Delay Faults in the Clock Network

A clock network is not only difficult to design, but also challenging to test. For high-performance designs with a rigorous clock-skew requirement, small defects in a clock tree network could lead to unexpected failures in the field and thus need to be identified during the manufacturing test. In this paper, we present a novel flush test procedure to determine if a clock network has any small delay faults. This method does not require any change of the clock network, but it does require a “special test clock signal,” which can be generated on the chip by using only standard cells. Experimental results of transistor-level simulation on benchmark circuits injected with resistive open defects in the layout show that the proposed method is capable of detecting a delay fault as small as 52.8 ps.

A rare case of malposition of central venous catheter detected by ultrasonography-guided saline flush test

Central venous catheter (CVC) insertion is associated with many potential complications; malposition of the catheter is one of them. A chest X-ray is routinely done to detect the malposition of...

How to Confirm Catheterization of Inner Branches in Aortic Endografting: The Universal Flush Test

Purpose: To describe a quick, simple, and reliable technique to confirm successful catheterization of a branched thoracic endograft’s inner branch. Technique: Accurate cannulation of inner branches can be verified through insertion and mild retraction of a Universal Flush angiographic catheter, whose tip hooks the branch and slightly opens. Conclusion: The use of an angiographic catheter with a curved tip is a safe and easy procedure that can be adopted to check the correct position inside the branch of an endograft designed for treatment of the aortic arch.

The accuracy of blood pressure measured by arterial line and non-invasive cuff in critically ill children.

BackgroundThe accuracy of arterial lines (AL) using the flush test or stopcock test has not been described in children, nor has the difference between invasive arterial blood pressure (IABP) versus non-invasive cuff (NIBP) blood pressure.MethodsAfter ethics approval and consent, we performed the flush test and stopcock test on AL (to determine over damping, under damping, and optimal damping), and determined the difference (NIBP–IABP) in systolic, diastolic, and mean blood pressure (ΔSBP, ΔDBP, and ΔMAP). The primary outcome was incidence (95 % CI) of optimally damped AL. Predictors of ΔBP (effect size (95 % CI)) were determined using multiple linear regression.ResultsThere were 147 AL tests in 100 enrolled patients with mean age 44.7 (SD 56) months, weight 16.8 (SD 18.3) kg, male 59 %, postoperative-cardiovascular 52 %, peripheral-AL 78 %, inotropes 29 %, vasodilators 15 %, and ventilated 73 %. The flush test performed in 66 patients (45 %) showed optimal damping in 30 (46 %; 95 % CI 34, 57 %), over damping in 25 (38 %) and under damping in 11 patients (17 %). The stopcock test was over-damped in 128/146 patients (88 %), with the same damping as the flush test in 24/64 (38 %). In optimally damped (flush test) AL, ΔSBP, ΔDBP, and ΔMAP were 0.8 (SD 12.2), −5.2 (SD 8.7), and −4.9 (7.6) respectively. A second set of AL tests was done 2 h later on the same day in 62 patients; AL damping often changed (10/28 flush tests) and ΔBPs correlated poorly (r = 0.31–0.55). Predictors (effect size) of ΔDBP were vasodilator infusion (15.6 (2.9 to 28.3); p = 0.016) and optimal damping (−7.2 (−12.2 to 2.2); p = 0.005); and of ΔMAP were vasodilator infusion (10.0 (−0.3 to 20.4); p = 0.057) and optimal damping (−4.0 (−8 to 0.1); p = 0.058). There were no independent predictors of damping category (n = 66 flush tests).ConclusionsOptimally damped AL occur in half of critically ill children, and this is not predictable. There is much variability in ∆BP between NIBP and the gold standard IABP, and this varies even in the same patient on the same day, and is not easily predictable. In critically ill children, NIBP may not be accurate enough to guide management, and more attention to ensuring the AL is optimally damped is needed.Electronic supplementary materialThe online version of this article (doi:10.1186/s13054-016-1354-x) contains supplementary material, which is available to authorized users.

Saline Flush Test: Can Bedside Sonography Replace Conventional Radiography for Confirmation of Above-the-Diaphragm Central Venous Catheter Placement?

Resuscitation often requires rapid vascular access via central venous catheters. Chest radiography is the reference standard to confirm central venous catheter placement and exclude complications. However, radiographs are often untimely. The purpose of this study was to determine whether dynamic sonographic visualization of a saline flush in the right side of the heart after central venous catheter placement could serve as a more rapid confirmatory study for above-the-diaphragm catheter placement. A consecutive prospective enrollment study was conducted in the emergency departments of 2 major tertiary care centers. Adult patients of the study investigators who required an above-the-diaphragm central venous catheter were enrolled during the study period. Patients had a catheter placed with sonographic guidance. After placement of the catheter, thoracic sonography was performed. The times for visualization of the saline flush in the right ventricle and sonographic exclusion of ipsilateral pneumothorax were recorded. Chest radiography was performed per standard practice. Eighty-one patients were enrolled; 13 were excluded. The mean catheter confirmation time by sonography was 8.80 minutes (95% confidence interval, 7.46-10.14 minutes). The mean catheter confirmation time by chest radiograph availability for viewing was 45.78 minutes (95% confidence interval, 37.03-54.54 minutes). Mean sonographic confirmation occurred 36.98 minutes sooner than radiography (P< .001). No discrepancy existed between sonographic and radiographic confirmation. Confirmation of central venous catheter placement by dynamic sonographic visualization of a saline flush with exclusion of pneumothorax is an accurate, safe, and more efficient method than confirmation by chest radiography. It allows the central line to be used immediately, expediting patient care.

Scan Chain Masking for Diagnosis of Multiple Chain Failures in a Space Compaction Environment

Diagnosis is extremely important to ramp up the yield during the integrated circuit manufacturing process. It reduces the time to market and product cost. Limited observability due to test response compaction negatively affects the diagnosis procedure. When multiple chains, mapped to a single compactor, fail, diagnosis becomes extremely difficult. The procedure is even more complicated because when a circuit fails the flush test, not all the patterns are applied. Only a few of the patterns are applied and the observed responses are used to diagnose the faulty chains. In this paper, we have proposed an efficient masking strategy that will be very useful for diagnosis of scan chains when multiple scan chains fail. The proposed strategy uses the redundancy in fault detection by the test patterns and masks scan chains in such a way that enough information can be provided with small increase in test pattern count. A new tester architecture that will select and apply only those patterns having enough information for diagnosis has also been proposed. Diagnostic resolution and first hit index achieved by our method are very close to their ideal values, which validate the applicability of our approach.

Cognition and autonomic function in schizophrenia: Inferior cognitive test performance in electrodermal and niacin skin flush non-responders

BackgroundPatients with schizophrenia suffer from a broad range of cognitive disturbances. The impact in terms of functional outcome is significant. There are also several reports of disturbed autonomic regulation in the disease. The present study examined cognitive function as well as psychophysiological parameters in patients with schizophrenia and healthy controls. MethodsTwenty-five patients and 14 controls were investigated with electrodermal activity (EDA), an oral niacin skin flush test and a comprehensive neurocognitive test program including the Wechsler battery (WAIS-R), Fingertapping Test, Trail Making Test, Verbal Fluency, Benton Visual Retention Test, Wisconsin Card Sorting Test and Rey Auditory Verbal Learning Test. ResultsThe patients generally had inferior test results compared to controls. Further analysis revealed that the EDA non-responding patient group explained this variation with significant lower test results than controls. On executive tests, EDA non-responders also performed significantly worse than EDA responding patients. The small group of niacin non-responding patients exhibited an even lower overall test performance. Delayed niacin flush also correlated inversely with psychomotor function and IQ in the patients. ConclusionThe findings support the hypothesis of a neurodevelopment disturbance affecting both autonomic function and higher cortical function in schizophrenia.

Coiling of central venous catheter in right internal jugular vein.

Sir, We read with interest the article written by Goyal et al.[1] describing a case of coiling of central venous catheter (CVC) in left subclavian vein. The authors have reported it as a rare complication, and we do not agree with this statement. Malatinský et al.[2] in 1976 presented a series of 378 radiographically controlled CVC placements and reported pure loop formations (coiling) in 2.9% of the cases. Supraclavicular subclavian approach was used in the majority of the patients and the authors explain this as a reason for relatively low incidence rates in their series as compared to other studies.[2] We report a case of coiling of central venous catheter in right internal jugular vein (IJV) in a 36-year-old patient admitted postoperatively in intensive care unit (ICU) following evacuation of large extradural hematoma. The CVC was placed in the operation theatre under ultrasound guidance. Intraoperatively the waveform was damped, and the flow of fluids was slow, but it was considered secondary to rotation of the neck and labeled as “positional”. Just after admission to the ICU a “flush test” was performed, and it was positive; 5–10 mL of normal saline was injected with force using a syringe and fluid thrill was felt in the ipsilateral neck region with the palmer aspect of the hand.[3] Subsequent chest X-ray confirmed coiling of CVC in right IJV [Figures ​[Figures1a1a and ​andbb]. Figure 1 (a) Chest X-ray anteroposterior view with coiled central venous catheter in right internal jugular vein, (b) Coiled central venous catheter after removal Factors predisposing to coiling and catheter malpositions are: Retrograde venous flow secondary to IJV valve incompetence in patients with chronic obstructive pulmonary disease, primary pulmonary hypertension and prior cannulations and catheterizations of the IJV[4,5] Retrograde venous flow in patients with high intrathoracic and intrabdomical pressures Seldinger technique: The catheter is inserted over the guidewire and placed in the central vein. During this procedure sometimes the guidewires are removed before the CVC are properly positioned in the superior vena cava. Resistance encountered in inserting the CVC then leads to excessive pressure applications, which then predisposes to malpositioning. Common sites of resistance are the junction of first rib and clavicle for the subclavian vein and the junction of venous tributaries for the IJV and brachiocephalic vein.

Taiwan schizophrenia linkage study: Lessons learned from endophenotype‐based genome‐wide linkage scans and perspective

Taiwan Schizophrenia Linkage Study (TSLS) was initiated with a linkage strategy for locating multiple genes, each of small to moderate effect, and aimed to recruit a large enough sample of pairs of affected siblings and their families ascertained from a multisite study. With a sample of 607 families successfully recruited, a total of 2,242 individuals (1,207 affected and 1,035 unaffected) from 557 families were genotyped using 386 microsatellite markers spaced at an average of 9-cM intervals. Here the author reviews the establishment of TSLS and initial signal derived from linkage scan using the diagnosis of schizophrenia. Based on the limited success of the initial linkage analysis, a sufficient-component causal model is proposed to incorporate endophenotypes and genes for schizophrenia. Four types of candidate endophenotype measured in TSLS, including schizotypal personality, Continuous Performance Test, Wisconsin Card Sorting Test, and niacin skin flush test, are briefly described. The author discusses different strategies of linkage analysis incorporating these endophenotypes, including quantitative trait loci (QTL) linkage analysis, clustering-derived subgroups, ordered subset analysis (OSA), and latent classes for linkage scan. Then the author summarizes the linkage signals generated from seven studies of endophenotype-based linkage analysis using TSLS, including QTL scan of neurocognitive performance, QTL scan of niacin skin flush, the family cluster of attention deficit and execution deficit, OSA by schizophrenia-schizotypy factors, nested OSA by age at onset and neurocognitive performance, and the latent class of deficit schizophrenia for linkage analysis. The perspective of combining next-generation sequencing with linkage analysis of families is also discussed.

Invasive blood pressure monitoring systems in the ICU

Invasive blood pressure monitoring is the most reliable method in critically ill patients. Noninvasive oscillometric pressure monitoring is also widely used in the ICU, and discrepancies between the methods are common. Inclusion of a blood-conserving device may influence the fidelity of the system and reliability of the invasive pressure values. We examined the dynamic response characteristics of the monitoring systems with and without the blood-conserving device, and assessed agreement between invasive and noninvasive blood pressures. Fifty-three invasive arterial blood pressure monitoring systems were evaluated over an 8-week period. A standard fast flush test was performed. The natural frequency (Fn) and the amplitude ratio of the invasive monitoring systems were calculated. Simultaneous invasive and noninvasive blood pressures were recorded, and the agreement between two methods was evaluated. The Fn was significantly higher (15.7 ± 5.1 Hz) in the systems without the blood-conserving device than in the systems containing the device (9.1 ± 2.6 Hz). There was no significant difference in the amplitude ratio. Significant differences were observed between invasive and noninvasive pressures, with systolic pressure showing more variability than the mean arterial pressure. Inclusion of a blood-conserving device in the existing monitoring circuit may affect its dynamic response characteristics. Discrepancies between invasive and noninvasive pressures are common, with systolic pressure showing more variability than the mean arterial pressure. The low Fn of the invasive monitoring system could be a contributing factor to the discrepancy between two methods.

Effectiveness of “saline flush test” in detecting misplaced subclavian catheter into the ipsilateral internal jugular vein: A preliminary report

Effectiveness of “saline flush test” in detecting misplaced subclavian catheter into the ipsilateral internal jugular vein: A preliminary report