Use of appropriate statistical tools in biomedical research: Current trend & status.

Background & objectives: Due to lack of appropriate statistical knowledge, published research articles contain various errors related to the design, analysis and interpretation of results in the area of biomedical research. If research contains statistical error, however, costly, it may be of no use and the purpose of the investigation gets defeated. Many biomedical research articles published in different peer reviewed journals may retain several statistical errors and flaws in them. This study aimed to examine the trend and status of application of statistics in biomedical research articles. Study design, sample size estimation and statistical measures are crucial components of a study. These points were evaluated in published original research articles to understand the use or misuse of statistical tools. Methods: Three hundred original research articles from the latest issues of selected 37 journals were reviewed. These journals were from the five internationally recognized publication groups (CLINICAL KEY, BMJ Group, WILEY, CAMBRIDGE and OXFORD) accessible through the online library of SGPGI, Lucknow, India. Results: Among articles assessed under present investigation, 85.3 per cent (n=256) were observational, and 14.7 per cent (n=44) were interventional studies. In 93 per cent (n=279) of research articles, sample size estimation was not reproducible. The simple random sampling was encountered rarely in biomedical studies even though none of the articles was adjusted by design effect and, only five articles had used randomized test. The testing of assumption of normality was mentioned in only four studies before applying parametric tests. Interpretation & conclusions: In order to present biomedical research results with reliable and precise estimates based on data, the role of engaging statistical experts need to be appreciated. Journals must have standard rules for reporting study design, sample size and data analysis tools. Careful attention is needed while applying any statistical procedure as, it will not only help readers to trust in the published articles, but also rely on the inferences the published articles draw.

Study to Test and Operationalize Preventive Approaches for CKD of Undetermined Etiology in Andhra Pradesh, India.

INTRODUCTION: High prevalence of chronic kidney disease (CKD) not associated with known risk factors has been reported from coastal districts of Andhra Pradesh. The Study to Test and Operationalize Preventive Approaches for Chronic Kidney Disease of Undetermined Etiology in Andhra Pradesh (STOP CKDu AP) aims to ascertain the burden (prevalence and incidence) of CKD, the risk factor profile, and the community perceptions about the disease in the Uddanam area of Andhra Pradesh. METHODS: Study participants will be sampled from the Uddanam area using multistage cluster random sampling. Information will be collected on the demographic profile, occupational history, and presence of conventional as well as nonconventional risk factors. Glomerular filtration rate (GFR) will be estimated using the Chronic Kidney Disease Epidemiology Collaboration equation, and proteinuria will be measured. All abnormal values will be confirmed by repeat testing after 3 months. Cases of CKD not associated with identified etiologies will be identified. Biospecimens will be stored to explore future hypotheses. The entire cohort will be followed up every 6 months to determine the incidence of CKD and to identify risk factors for decline in kidney function. Qualitative studies will be performed to understand the community perceptions and expectations with respect to the interventions. IMPLICATIONS: CKD is an important public health challenge in low- and middle-income countries. This study will establish the prevalence and determine the incidence of CKD not associated with known risk factors in a reported high-burden region, and will provide insights to help design targeted health systems responses. The findings will contribute to the policy development to tackle CKD in the region and will permit international comparisons with other regions with similar high prevalence.

Scales of measurement and presentation of statistical data.

Measurement scale is an important part of data collection, analysis, and presentation. In the data collection and data analysis, statistical tools differ from one data type to another. There are four types of variables, namely nominal, ordinal, discrete, and continuous, and their nature and application are different. Graphs are a common method to visually present and illustrate relationships in the data. There are several statistical diagrams available to present data sets. However, their use depends on our objectives and data types. We should use the appropriate diagram for the data set, which is very useful for easily and quickly communicating summaries and findings to the audience. In the present study, statistical data type and its presentation, which are used in the field of biomedical research, have been discussed.

Multiparametric imaging-based differentiation of lymphoma and glioblastoma: using T1-perfusion, diffusion, and susceptibility-weighted MRI.

AIM: To compare the diagnostic performance of T1 perfusion magnetic resonance imaging (MRI), diffusion-weighted imaging (DWI), and susceptibility-weighted imaging (SWI) for differentiating primary central nervous system lymphoma (PCNSL) and glioblastoma (GBM). MATERIALS AND METHODS: This retrospective study comprised a cohort of 70 patients with glioblastoma and 30 patients with PCNSL. T1 perfusion MRI-derived rCBV_corr (leakage corrected relative cerebral blood volume), apparent diffusion coefficient (ADC) derived from DWI, and intratumoural susceptibility signals intensity (ITSS) measured on SWI were evaluated in these 100 patients. The Mann-Whitney U-test was used for pairwise comparison between groups. The diagnostic performance for differentiating PCNSL from glioblastoma was evaluated by using univariate and multivariable logistic regression analyses and receiver operating characteristic (ROC) analysis. RESULTS: Minimum ADC, maximum rCBVs_corr, kep (back flux exchange rate), and ITSS scores were significantly lower in patients with PCNSL than in those with glioblastoma (p<0.05). On ROC analysis, ITSS showed the best discrimination ability for differentiation of GBM and PCNSL with an area under the ROC curve (AUC) of 0.80. rCBV_corr and ADC showed AUCs of 0.68 and 0.63, respectively. Multiparametric assessment using ADC, rCBV_corr, kep, and ITSS scores significantly increased the diagnostic ability for differentiating PCNSL from GBM as compared to mean ADC, mean rCBV_corr, and ITSS alone or a combination of these parameters. The multiparametric model could correctly discriminate 84% of tumours with a sensitivity and specificity of 90% and 70% with an AUC of 0.92. CONCLUSION: Multiparametric MRI evaluation using DWI, T1 perfusion MRI, and SWI enabled reliable differentiation of PCNSL and GBM in the majority patients, and these results support an integration of advanced MRI techniques for the diagnostic work-up of patients with these tumours.

Long-term outcomes post chronic total occlusion intervention-implications of completeness of revascularization.

BACKGROUND: Long term clinical outcomes post chronic total occlusion (CTO) intervention may depend not only on CTO success/failure alone but also on Completeness of revascularization. OBJECTIVES: To determine long term outcomes post CTO intervention and relate them to both success versus failure and Complete Revascularization (CR) versus Incomplete Revascularization (IR). METHODS: Consecutive patients taken up for CTO intervention with at-least one CTO vessel between Jan 2006 to Dec 2015 were included. Clinical, procedural and follow up details were recorded in a pre-specified custom made software. Primary endpoint of the study was survival free of major adverse event individual, death, myocardial infarction (MI), repeat revascularisation (percutaneous coronary intervention [PCI], or coronary artery bypass grafting (CABG) and recurrent or continued angina. Each individual adverse event was considered as a secondary end point. RESULTS: A total of 632 patients were enrolled in study with follow up data available in 549 (86%) constituting the study group with 490 (89.3%) success and 59 (11.7%) failure. Complete revascularization (CR) was obtained in 410 (74.7%). Follow up was median 2.9 years with inter-quartile range 1.1-4.8 years. Kaplan Meier survival analysis showed a better EFS with both CTO success versus failure (P = 0.03)and CR versus IR (P = 0.017). Individual adverse outcomes however were not significantly different in CTO success versus failure group but significantly better when analyzed with respect to CR versus IR including death (P = 0.049) and recurrent angina (P = 0.024). Repeat intervention and MI were not different by either analysis. CONCLUSIONS: Successful CTO PCI results in a better long term event free survival but the difference between the groups is more if analyzed with respect to completeness of revascularization rather than CTO success/failure alone.

Pan masala habits and risk of oral precancer: A cross-sectional survey in 0.45 million people of North India.

OBJECTIVES: This cross-sectional community based study was conducted to estimate the prevalence of consumption habits for non tobacco pan masala (ASU) and the risk of developing oral precancer in North India. METHODS: This study was conducted in the old town of Lucknow city in the state of Uttar Pradesh in India. Subjects residing for more than 6 months and aged 15 years or above, were enrolled in the study after their informed consent. A two page survey tool was used to collect the data. A three times more matched sample of non users was randomly obtained from this data to analyze and compare the final results. RESULTS: 0.45 million subjects were surveyed. Majority of tobacco users were in the age group of 20-35 years among males and 35-39 years among females. Consumption of non tobacco pan masala among males as well as females was most common in 15-19 years of age group. Prevalence of oral precancer (leukoplakia, submucous fibrosis, erythroplakia, lichen planus, smokers palate and verrucous hyperplasia) was 3.17% in non tobacco pan masala users and 12.22% in tobacco users. The odds of developing oral precancer in non tobacco pan masala users was 20.71 (18.79-22.82) and in tobacco users was 88.07 (84.02-92.31) at 95% confidence interval against non users of both. CONCLUSION: The odds of developing oral precancer even with consumption of pan masala is high, even when it is consumed without tobacco. It is hence recommended to discourage this habit.

Trends, prospects and deprivation index of disability in India: Evidences from census 2001 and 2011.

BACKGROUND: Since the dawn of civilization, disabilities have existed in various dimensions of human life. World Health Organization (WHO) defines disability as an umbrella term, covering impairments, activity limitations, and participation restrictions. Globally, approximately 1 billion people have some form of disability, and approximately 20% have significant functioning impairments. OBJECTIVE: This study aims to estimate the level, trends and prospects of disability in 640 districts of India. Data for the present study has been taken from Census of India, 2001 and 2011. METHODS: A Disability Index was calculated at the district level, and state level indexing was done using the Disability Deprivation Index. The population for the year 2021 was projected using the exponential growth rate method. The Disability Deprivation Index was calculated using child labor, adult unemployment, illiteracy, and the ratio of beggars in the disabled population. RESULTS: The study reveals that the proportion of the disabled population in India was 2.10% in 2001, which increased to 2.21% in 2011. According to the Disability Deprivation Index, Maharashtra was the best-performing state in 2011. There were 4.90 million new cases of disability in India during 2001-11, out of which 1.52 million cases belonged to non-congenital disability. CONCLUSIONS: There is a rise in the disabled population in India, which needs special attention. The working status of the disabled is gloomy. The majority of the disabled people are non-working and need adequate rehabilitation measures that would facilitate employment.

Disparity in maternal, newborn and child health services in high focus states in India: a district-level cross-sectional analysis.

OBJECTIVES: To examine the level and trend in the coverage gap of a set of interventions of maternal and child health services using a summary index and to assess the disparity in usage of maternal and child health services in the districts of high focus states of India. DESIGN: Data for the present study are taken from the Annual Health Survey (AHS), 2010-2013 and Census of India, 2011. SETTINGS: This study used secondary data from states having higher mortality and fertility rates, termed as high focus states in India. PARTICIPANTS: District-level information regarding children aged 12-23 months and ever married women aged 15-49 years has been extracted from the AHS (2010-2013), and household amenities, female literacy and main workforce information has been obtained from the Census of India 2011. MEASURES: 2 summary indexes were calculated first for maternal and child health services and another for socioeconomic and development status, using data from AHS and Census. Cronbach's α was used to assess the internal consistency of the items used in the index. RESULTS: The result shows that the coverage gap is highest in Uttar Pradesh (37%) and lowest in Madhya Pradesh (21%). Converge gap and socioeconomic development are negatively correlated (r=-0.49, p=0.01). The average coverage gap was highest in the lowest quintile of socioeconomic development. There was an absolute change of 1.5% per year in coverage gap during 2009-2013. In regression analysis, the coefficient of determination was 0.24, ß=-30.05, p=0.01 for a negative relationship between socioeconomic development and coverage gap. CONCLUSIONS: There is a significant disparity in the usage of maternal and child healthcare services in the districts of India. Resource-rich people (urban residents and richest quintile) are way ahead of marginalised people (rural residents and poorest quintile) in the usage of healthcare services.

Left main PCI: An observational analysis from large single-centre experience.

BACKGROUND: Although trials have shown efficacy of unprotected left main percutaneous coronary intervention (uLMPCI), data from Indian subcontinent are lacking. Hence, we planned this observational analysis of single-center uLMPCI data. OBJECTIVES: To study long-term outcome after uLMPCI and identify predictors of adverse outcome. METHODS: Case details of 62 consecutive patients of uLMPCI between 2006 and 2013 were retrieved from a computerized database wherein detailed records were maintained. RESULTS: Mean follow-up duration was 669.8±404.2 days. Procedural success rate was 98.4%. Primary endpoint was composite of major adverse cardiovascular and cerebrovascular events (MACCE), which included cardiac death (CD), cerebrovascular accident (CVA), myocardial infarction (MI), and need for repeat intervention (RI) at three years. MACCE occurred in 13 (20.9%) patients. Cardiac death (CD), (including possible stent thrombosis), RI, and CVA occurred in 6 (9.7%), 5 (8%), and 2 (3.2%) patients, respectively. Overall three-year MACCE-free survival rate was 76.7%. Event-free survival rate was similar among patients who underwent uLMPCI alone and patients who underwent uLMPCI along with additional one-vessel PCI [(88.9% vs 81.8%), p=0.492], while survival rate was lower in patients who underwent uLMPCI along with PCI of additional two or more vessels (40%, p=0.036). Patients with syntax score ≤32 had higher event-free survival rate than those with syntax score >32 [(87.1% vs 33.3%), p=0.001]. Syntax score >32 was the only independent predictor of adverse outcome. CONCLUSION: uLMPCI is safe and effective alternative to CABG for LM alone and LM plus single-vessel disease with syntax score ≤32.

Epidemiology of substance abuse in the population of Lucknow.

BACKGROUND: Habit of consuming tobacco and areca-nut containing substances is in vogue in Lucknow as a part of the Nawabi culture. Hence, this study was planned with an aim to generate evidence for the prevalence of habits of substance abuse by the population of Lucknow and know their socio-demographic profile. METHODOLOGY: Population based cross-sectional study was conducted by organizing oral health check-up camps in randomly selected rural and urban parts of Lucknow, the capital city of Uttar Pradesh, which is the most populated state of India. Patients were enrolled after obtaining informed consent. A structured and validated questionnaire based tool was administered by a team of trained dental surgeons for collecting the desired information through interview and their oral cavity examination. RESULTS: A total of 3437 subjects were enrolled in the study, out of which 82.9% were male and 17.1% were female. Among them, 64.6% subjects belonged to rural domiciliary status, by religion, 80.6% and 18.5% of the subjects were Hindu and Muslims respectively. The most prevalent habit was consumption of smokeless tobacco substances, of which pan masala with tobacco (gutkha) was the most prevalent substance of abuse. CONCLUSION: Smokeless tobacco consumption was highly prevalent in the population surveyed. It is recommended to formulate and implement strong preventive strategies. Also, steps should be taken to increase the awareness of the harmful consequences of these habits.

DTI correlates of cognition in conventional MRI of normal-appearing brain in patients with clinical features of subacute combined degeneration and biochemically proven vitamin B(12) deficiency.

BACKGROUND AND PURPOSE: Vitamin B12 deficiency may cause neural injury that results in cognitive deficits. The main purpose of our study was to evaluate morphometric and microstructural changes in the brain and relate them to cognition in subacute combined degeneration of the spinal cord and patients with biochemically deficient vitamin B12. MATERIALS AND METHODS: Fifty-one patients were recruited and underwent nerve-conduction velocity tests and routine hematologic examinations. Serum vitamin B12 and homocystine levels were also measured. All patients and 46 age- and sex-matched controls underwent cervical spine and brain MR imaging along with cognition tests. MR imaging included conventional scans and DTI. Voxel-based morphometry was performed for determining the WM and GM volumes, based on T1-weighted images. DTI measures that included fractional anisotropy, ADC, radial diffusivity, and axial diffusivity were determined by using tract-based statistics. RESULTS: None of the patients showed any abnormality on conventional MR imaging. No significant changes in GM and WM volumes were observed in patients compared with controls. Significant reductions in the fractional anisotropy and an increase in ADC and radial diffusivity values were observed in multiple brain regions in patients compared with controls. These changes were confirmed on the region-of-interest analysis. Neuropsychological scores were significantly different in patients compared with controls and showed significant correlation with fractional anisotropy and radial diffusivity in a few brain regions. CONCLUSIONS: Microstructural changes are seen in WM regions on DTI in patients with vitamin B12 deficiency and correlate with cognition scores. DTI can be used for objective assessment of microstructural changes in the brain in vitamin B12 deficiency.

T1-weighted dynamic contrast-enhanced MR evaluation of different stages of neurocysticercosis and its relationship with serum MMP-9 expression.

BACKGROUND AND PURPOSE: Epileptogenesis in NCC is associated with perilesional inflammation and disruption in BBB. We quantified BBB in different stages of NCC by using DCE-MR imaging to look for the differences in perfusion indices and to correlate these indices with serum MMP-9 expression. MATERIALS AND METHODS: DCE-MR imaging along with conventional MR imaging was performed in 57 single cysticercous brain lesions to quantify the kep, K(trans), and ve around the lesions, which were in different stages of evolution. There were 6 lesions in the vesicular stage and 17 lesions each in the colloidal, granular-nodular, and calcified stages. Serum MMP-9 was quantified from all patients, whereas perfusion indices were quantified from all stages except for the vesicular stage. RESULTS: We observed significant differences among the 3 stages of NCC in serum MMP-9 expression as well as DCE-derived kep values. In addition, kep showed a strongly significant positive correlation with MMP-9 expression when modeled with the individual stage of the disease as well as with all stages when pooled together. Other DCE-derived hemodynamic and pharmacokinetic parameters showed inconsistent differences with each stage of the disease. The correlation of DCE-derived parameters with serum MMP-9 expression and edema volume also showed inconsistency with the stage of the disease. CONCLUSIONS: We conclude that kep correlates best with serum MMP-9 expression among the pharmacokinetic indices and most closely represents the degree of BBB breakdown, which is highest in the colloidal stage and lowest in the calcified stage. kep may be used as a noninvasive image biomarker of BBB breakdown in different stages of NCC.

Patterns and determinants of dyslipidaemia in 'Young' versus 'Not so Young' patients of coronary artery disease: a multicentric, randomised observational study in northern India.

AIMS: The aims of the study were to ascertain difference in lipid levels of 'Young' onset of coronary artery disease (CAD) (≤ 45 years) vs. 'Not so Young' onset of CAD (≥ 55 years) among north Indians and also to investigate determinants of 'dyslipidaemia' in CAD patients. METHODS: This was a prospective, multicentric, randomised, observational study carried in eight centres of UP, India. All blood investigations were performed employing a central laboratory. RESULTS: Out of a total 435 patients studied, 218 were in the 'young group' (YG) and 235 were in the 'Not so Young Group' (NSYG). Dyslipidaemia was more common in YG as evident by significantly higher levels of total cholesterol, triglycerides, low- and very low-density lipoprotein cholesterol as compared to NSYG. Diabetes, hypertension, urban lifestyle, and family history of CAD were found to be important determinants of dyslipidaemia in YG. CONCLUSION: We conclude that lipid levels among north Indians are significantly higher in younger patients with CAD when compared with elderly.

Understanding epileptogenesis in calcified neurocysticercosis with perfusion MRI.

OBJECTIVES: Calcified cysticercus larva with perilesional abnormality is thought to be responsible for seizures in patients with neurocysticercosis (NCC). However, it is not well understood why some calcified cysts are associated with seizures even without perilesional abnormality. METHODS: The study group consists of 30 subjects from an ongoing survey for disease burden estimation of a swine farming community who had a single calcified lesion without any perilesional abnormality with or without presentation of seizures. Each group consisted of 15 patients with calcified cysts and was labeled as asymptomatic and symptomatic. We performed dynamic contrast-enhanced (DCE) MRI on all these subjects and determined serum matrix metalloproteinase-9 (MMP-9) levels and MMP-9 gene polymorphisms. RESULTS: DCE-MRI-derived rate transfer constant (k(ep)) and serum MMP-9 levels showed significant differences between symptomatic and asymptomatic subjects. We observed an increase in the MMP-9 levels, k(ep), and the volume transfer coefficient (k(trans)) in these lesions. We also observed a significant increase in MMP-9 (R279Q) gene polymorphism in symptomatic subjects compared with asymptomatic and control subjects. CONCLUSIONS: Perilesional inflammation, which varies from symptomatic to asymptomatic subjects, can be quantified using DCE-MRI in calcified cysticercosis and may help distinguish these 2 groups with similar imaging findings. The observed increase in k(ep) with serum MMP-9 levels suggests that the former may serve as a biomarker of MMP-9 levels in these subjects. The significant MMP-9 (R279Q) gene polymorphism in symptomatic subjects might explain the differences in the observed DCE-MRI indices between symptomatic and asymptomatic subjects.

Prospective comparison of new Japanese Association for Acute Medicine (JAAM) DIC and International Society of Thrombosis and Hemostasis (ISTH) DIC score in critically ill septic patients.

INTRODUCTION: We prospectively compared the new Japanese Association for Acute Medicine (JAAM) score with the International Society of Thrombosis and Hemostasis (ISTH) score for diagnosis of disseminated intravascular coagulation (DIC) in septic patients admitted in a general critical care intensive care unit. MATERIAL AND METHOD: Septic patients with platelet count of <150 × 10(9)/L were included. Both DIC scores were estimated from day 1 to day 4 along with APACHE II and SOFA scores. RESULTS: Out of the 148 blood samples drawn from 42 patients (28 male & 14 female) the JAAM and ISTH DIC scores had an overall significant agreement (k=0.246, p<0.001) in 83 samples. JAAM score had higher diagnostic rates on all four days. Significant (p ≤ 0.001) day wise variation existed in JAAM and ISTH DIC scores. Correlation between JAAM DIC and ISTH DIC scores on day 1 (r=0.631) & day 4 (r=0.609) was significant (p<0.001). Pneumonia was the predominant cause of sepsis. Twenty seven (64.3%) patients died during their stay in ICU. Amongst DIC patients both severity scores (SOFA/APACHE II) and DIC scores (JAAM/ISTH) did not discriminate between survivors and non-survivors. Health care associated infection (p=0.040), high lactate levels (p=0.020) on day 1 and high procalcitonin levels (p=0.036) were found to have significant discriminating ability between survivors and non-survivors. Significantly shorter length of stay was observed amongst non-survivors (p=0.002). CONCLUSIONS: In sepsis the JAAM DIC score identified most of the patients diagnosed by the overt ISTH criteria, but failed to discriminate between survivors and non-survivors amongst DIC patients.

Lack of association between Glu298Asp polymorphism and coronary artery disease in North Indians.

Nitric Oxide (NO) is an important molecule carrying number of different functions in humans. Published studies suggest that it may inhibit several key steps involved in the pathogenesis of atherosclerosis. Inhibition or reduction of NO due to Glu298Asp polymorphism may accelerate atherosclerosis. The aim of this study was to determine whether Glu298Asp polymorphism is implicated in the pathogenesis of coronary artery disease (CAD) among North Indian population from the state of Uttar Pradesh, India. We selected 253 CAD patients and 174 healthy, normotensive, non-diabetic controls, which were matched for gender and ethnicity. The Glu298Asp (rs1799983) variant was detected by genotyping subjects, using a polymerase chain reaction followed by restriction fragment length polymorphism. There was no significant difference found in the genotypic and allelic frequencies between patients and controls. Our study indicated that Glu298Asp polymorphism does not play any critical role in the pathogenesis of CAD, at least in North Indian population.

In vivo proton MR spectroscopy evaluation of pyogenic brain abscesses: a report of 194 cases.

BACKGROUND AND PURPOSE: The combination of nonspecific clinical findings and similarities in morphologic appearances on imaging often makes it difficult to distinguish abscesses from other brain lesions. We present a retrospective analysis of in vivo (1)H-MR spectroscopy data for characterization of the etiology of the brain abscess based on the established criteria and demonstrate the sensitivity and specificity of metabolite markers assigned to specific bacterial groups defined by the microbial culture in 194 patients. MATERIALS AND METHODS: Conventional MR imaging and in vivo (1)H-MR spectroscopy data were evaluated from patients with pyogenic brain abscesses, with ages ranging from 3 to 60 years. Imaging and (1)H-MR spectroscopy were performed on a 1.5T scanner. After MR imaging was performed and analyzed, pus aspirates were obtained in all patients. The causative organisms were confirmed by pus cultures. RESULTS: Resonance of AAs with or without other metabolites on in vivo (1)H-MR spectroscopy was observed in 80% of abscesses, with a sensitivity and specificity of 0.72 and 0.30, respectively. Most obligate anaerobes and some facultative anaerobes showed the presence of Lac/Lip, AAs, and Ac with or without Suc. Mostly obligate aerobes or facultative anaerobes showed the presence of Lac and AAs, with or without lipids. CONCLUSIONS: The presence of AAs on in vivo (1)H-MR spectroscopy is a sensitive marker of pyogenic abscess, but its absence does not rule out a pyogenic etiology. The presence of Ac with or without Suc favors an anaerobic bacterial origin of the abscess; however, this may also be seen in some of the abscesses secondary to facultative anaerobes.

Patient controlled sedation during central neuraxial anesthesia.

BACKGROUND: Patient controlled sedation (PCS) gives liberty to patients to choose the time of sedative administration to attain a desired level of comfort. AIMS: The PCS use was evaluated in patients during surgery under central neuraxial blockade. SETTINGS AND DESIGN: Prospective, cross-sectional, clinical study on consecutive patients in a tertiary care university hospital. MATERIALS AND METHODS: PCS technique, using propofol (1%) 2 ml in 2 min was used in 160 adult patients undergoing urologic procedures under central neuraxial block. We observed the time to first PCS activation by patient, duration of surgery, propofol dose, sedation score, hemodynamic stability, patient's acceptability, and the factors correlating with the PCS use. STATISTICAL ANALYSIS USED: Non-parametric two-tailed Pearson's test, univariate correlation analysis for the factors favoring PCS use followed by multivariate logistic regression analysis amongst correlating factors. RESULTS: In our cohort, the majority (83%) of the patients activated PCS during surgery under central neuraxial blocks at median time of 30 min and (17%) did not activate PCS. Female patients activated sedation earlier (median 15 min) than male patients (median 30 min). All patients were hemodynamically stable and without significant side effects. Multivariate analysis showed that sedative use significantly ( P < 0.05) correlated with female gender (odds ratio-3.54 [IR-2.64 to 4.73]) and prolonged surgery (>90 min). Majority (91%) of patients rated PCS technique excellent to good. CONCLUSIONS: PCS was very well accepted by patients during central neuraxial block. Propofol regimen (2 ml in 2 min) in PCS was safe, as it caused neither apnea nor significant hypotension.

Serial changes in the white matter diffusion tensor imaging metrics in moderate traumatic brain injury and correlation with neuro-cognitive function.

Diffuse axonal injury (DAI) that follows traumatic brain injury (TBI) is thought to be a major contributor to neurocognitive dysfunction that sometimes follows TBI. Conventional magnetic resonance imaging (MRI), diffusion tensor imaging (DTI) and neuropsychological tests (NPT) were performed on 38 TBI patients [hemorrhagic DAI (H-DAI, n=8), non-hemorrhagic (Nh-DAI, n=7), with no apparent DAI on conventional MRI (NA-DAI, n=23)] with a Glasgow Coma Scale score ranging between 9 and 13. The fractional anisotropy (FA) and mean diffusivity (MD) were quantified from different regions of the corpus callosum (CC), and peri-ventricular white matter (PWM) within 5-14 days and 6 months following TBI. Patients in all three groups showed decreased FA in the anterior limb of the internal capsule (ALIC) and the posterior limb of the internal capsule (PLIC), while the genu of the CC showed a decrease in the H-DAI group during the early period following TBI that persisted 6 months later, which appeared to be consistent with axonopathy. In patients without abnormalities on conventional MRI and DTI in the initial phase, a significant decrease in FA and increase in MD were observed in a few regions of the CC at 6 months, which was suggestive of demyelination/gliosis. The changes in FA and MD in the CC and PWM at 6 months follow-up showed significant correlation with some of the NPT performed in the three groups. DTI demonstrates axonopathy in the acute stage, as well as at secondary stages, at 6 months post-injury in the CC and PWM in regions of normal-appearing white matter on conventional MRI.