Sensitivity and specificity of phrenic nerve electrophysiology to predict mechanical ventilation in the Guillain-Barré syndrome.

INTRODUCTION/AIMS: In Guillain-Barré syndrome (GBS), the sensitivity and specificity of phrenic compound muscle action potential (CMAP) measurements to predict endotracheal mechanical ventilation are unknown. Hence, we sought to estimate sensitivity and specificity. METHODS: We performed a 10-year retrospective analysis of adult GBS patients from our single-center laboratory database (2009 to 2019). The phrenic nerve amplitudes and latencies before ventilation were recorded along with other clinical and demographic features. Receiver operating curve (ROC) analysis with area under the curve (AUC) was used to determine the sensitivity and specificity with 95% confidence interval (CI) for phrenic amplitudes and latencies in predicting the need for mechanical ventilation. RESULTS: Two hundred five phrenic nerves were analyzed in 105 patients. The mean age was 46.1 ± 16.2 years, with 60% of them being male. Fourteen patients (13.3%) required mechanical ventilation. The average phrenic amplitudes were lower in the ventilated group (P = .003), but average latencies did not differ (P = .133). ROC analysis confirmed that phrenic amplitudes could predict respiratory failure (AUC = 0.76; 95% CI, 0.61 to 0.91; P < .002), but phrenic latencies could not (AUC = 0.60; 95% CI, 0.46 to 0.73; P = .256). The best threshold for amplitude was ≥0.6 mV, with sensitivity, specificity, and positive and negative predictive values of 85.7%, 58.2%, 24.0%, and 96.4%, respectively. DISCUSSION: Our study suggests that phrenic CMAP amplitudes can predict the need for mechanical ventilation in GBS. In contrast, phrenic CMAP latencies are not reliable. The high negative predictive value of phrenic CMAP amplitudes ≥0.6 mV can preclude mechanical ventilation, making these a useful adjunct to clinical decision-making.

Persistent bacteremia predicts poor outcomes among neutropenic patients with carbapenem-resistant gram-negative bloodstream infections receiving appropriate therapy.

PURPOSE: Identifying persistent bacteremia early in patients with neutropenia may improve outcome. This study evaluated the role of follow-up blood cultures (FUBC) positivity in predicting outcomes among patients with neutropenia and carbapenem-resistant gram-negative bloodstream infections (CRGNBSI). METHODS: This retrospective cohort study conducted between December 2017 and April 2022 included patients more than 15 years old with neutropenia and CRGNBSI, who survived for ≥ 48 h, receiving appropriate antibiotic therapy and had FUBCs. Patients with polymicrobial bacteremia within 30 days were excluded. The primary outcome was 30 day mortality. Persistent bacteremia, septic shock, recovery from neutropenia, prolonged or profound neutropenia, requirement of intensive care and dialysis, and initiation of appropriate empirical therapy were also studied. RESULTS: In our study cohort of 155 patients, the 30 day mortality rate was 47.7%. Persistent bacteremia was common in our patient cohort (43.8%). Carbapenem resistant isolates identified in the study were K.pneumoniae (80%), E.coli (12.26%), P.aeruginosa (5.16%), A.baumanii (1.94%) and E.cloacae (0.65%). The median time for sending a FUBC was 2 days (IQR, 1-3 days). Patients with persistent bacteremia had higher mortality than those without (56.76% versus 32.1%; p < 0.001). Appropriate initial empirical therapy was given to 70.9%. Recovery from neutropenia occurred in 57.4% while 25.8% had prolonged or profound neutropenia. Sixty-nine percent (107/155) had septic shock and needed intensive care; 12.2% of patients required dialysis. Non-recovery from neutropenia (aHR, 4.28; 95% CI 2.53-7.23), presence of septic shock (aHR, 4.42; 95%CI 1.47-13.28), requirement of intensive care (aHR,3.12;95%CI 1.23-7.93), and persistent bacteremia (aHR,1.74; 95%CI 1.05-2.89) significantly predicted poor outcomes in multivariable analysis. CONCLUSION: FUBC showing persistent bacteremia predicted poor outcomes among neutropenic patients with carbapenem-resistant gram-negative bloodstream infections (CRGNBSI) and should be routinely reported.

Anemia requiring transfusion in breast cancer patients on dose-dense chemotherapy: Prevalence, risk factors, cost and effect on disease outcome.

PURPOSE: Dose-dense chemotherapy improves survival but with increased toxicity and treatment-related cost. We report the prevalence of anemia and the possible risk factors associated with chemotherapy-related anemia and determine the cost and time-delay associated with transfusion requirement in Indian patients with non-metastatic breast cancer on dose-dense preoperative chemotherapy. METHODS: In this study, triple-negative breast cancer (TNBC) patients were treated preoperatively with docetaxel and cyclophosphamide alternating with epirubicin and cisplatin every 2 weeks. Patients were evaluated for anemia pre- and post-chemotherapy. We examined trends in the red cell indices, transfusion requirement, time to transfusion, as well as risk factors associated with transfusion during treatment, along with delay in treatment due to anemia and the additional cost incurred. RESULTS: A total of 116 consecutive women with nonmetastatic TNBC were treated with preoperative chemotherapy. The median age was 44.5 years. 56.1% of patients had stage III disease. Anemia was detected at baseline in 54 (46.5%) patients with mild anemia (10-12 g/dl) in 42 (36.2%) patients and moderate anemia (8-10 g/dl) in 12 (10.3%) patients. During the course of treatment, all patients developed anemia. A total of 44 patients (37.9%) required transfusion during chemotherapy, with 55(47.4%) patients developing grade 1-2 anemia and 40 (34.5%) patients developing grade 3 anemia. The factors associated with anemia requiring transfusion were a steeper decline in hemoglobin after two cycles (OR 1.65, p = 0.02), low-grade tumor (OR 2.48, p = 0.03), and thrombocytopenia grade 3 or 4 (OR 4.35, p = 0.034), of which tumor grade and thrombocytopenia remained significant in multivariate analysis. Nearly one-fourth of the study population had a delay between two cycles of chemotherapy due to anemia. A median additional cost of INR 7000 was incurred among those requiring blood transfusion. CONCLUSION: Anemia is a common toxicity associated with dose-dense chemotherapy during curative breast cancer treatment leading to delay in treatment and increased cost. Low-grade tumor, grade 3 or 4 thrombocytopenia, and grade 2 or higher anemia after two cycles of chemotherapy are risk factors for blood transfusions during treatment.

Self-directed learning readiness of Indian medical students: a mixed method study.

BACKGROUND: Self-directed learning (SDL) is defined as learning on one's own initiative, with the learner having primary responsibility for planning, implementing, and evaluating the effort. Medical education institutions promote SDL, since physicians need to be self-directed learners to maintain lifelong learning in the ever-changing world of medicine and to obtain essential knowledge for professional growth. The purpose of the study was to measure the self-directed learning readiness of medical students across the training years, to determine the perceptions of students and faculty on factors that promote and deter SDL and to identify the role of culture and curriculum on SDL at the Christian Medical College, Vellore, India. METHODS: Guglielmino's SDL Readiness Scale (SDLRS) was administered in 2015 to six student cohorts (452 students) at admission, end of 1st, 2nd, 3rd and 4th year of training, and at the beginning of internship in the undergraduate medicine (MBBS) program. Analysis of variance (ANOVA) was used to compare SDL scores between years of training. 5 student focus groups and 7 interviews with instructors captured perceptions of self-direction. Transcripts were coded and analyzed thematically. RESULTS: The overall mean SDLRS score was 212.91. There was no significant effect of gender and age on SDLR scores. There was a significant drop in SDLRS scores on comparing students at admission with students at subsequent years of training. Qualitative analysis showed the prominent role of culture and curriculum on SDL readiness. CONCLUSIONS: Given the importance of SDL in medicine, the current curriculum may require an increase in learning activities that promote SDL. Strategies to change the learning environment that facilitates SDL have to be considered.

Environmental Factors Associated with High Fly Densities and Diarrhea in Vellore, India.

Diarrhea causes significant morbidity and mortality in Indian children under 5 years of age. Flies carry enteric pathogens and may mediate foodborne infections. In this study, we characterized fly densities as a determinant of infectious diarrhea in a longitudinal cohort of 160 urban and 80 rural households with 1,274 individuals (27% under 5 years of age) in Vellore, India. Household questionnaires on living conditions were completed at enrollment. Fly abundance was measured during the wet and dry seasons using fly ribbons placed in kitchens. PCRs for enteric bacteria, viruses, and protozoa were performed on 60 fly samples. Forty-three (72%) fly samples were positive for the following pathogens: norovirus (50%), Salmonella spp. (46.7%), rotavirus (6.7%), and Escherichia coli (6.7%). Ninety-one episodes of diarrhea occurred (89% in children under 5 years of age). Stool pathogens isolated in 24 of 77 (31%) samples included E. coli, Shigella spp., Vibrio spp., Giardia, Cryptosporidium, and rotavirus. Multivariate log-linear models were used to explore the relationships between diarrhea and fly densities, controlling for demographics, hygiene, and human-animal interactions. Fly abundance was 6 times higher in rural than urban sites (P < 0.0001). Disposal of garbage close to homes and rural living were significant risk factors for high fly densities. The presence of latrines was protective against high fly densities and diarrhea. The adjusted relative risks of diarrheal episodes and duration of diarrhea, associated with fly density at the 75th percentile, were 1.18 (95% confidence interval [CI], 1.03 to 1.34) and 1.15 (95% CI, 1.02 to 1.29), respectively. Flies harbored enteric pathogens, including norovirus, a poorly documented pathogen on flies.

Effect of Non-Rotavirus Enteric Infections on Vaccine Efficacy in a ROTASIIL Clinical Trial.

This study examined the relative proportion of enteric pathogens associated with severe gastroenteritis (GE) among children younger than 2 years in a phase III efficacy trial of the ROTASIIL® vaccine in India, evaluated the impact of co-infections on vaccine efficacy (VE), and characterized the association between specific pathogens and the clinical profile of severe GE. Stored stool samples collected from cases of severe GE in the phase III trial were tested by quantitative polymerase chain reaction using TaqMan™ Array Cards. Etiology was attributed by calculating the adjusted attributable fraction (AF) for each pathogen. A test-negative design was used to estimate VE. The pathogens with the highest AFs for severe diarrhea were rotavirus (23.5%), adenovirus 40/41 (17.0%), Shigella spp./enteroinvasive Escherichia coli, norovirus GII, enterotoxigenic E. coli, and Cryptosporidium spp. A considerable proportion of the disease in these children could not be explained by the pathogens tested. Severe GE cases associated with rotavirus and Shigella spp. were more likely to have a longer duration of vomiting and diarrhea, respectively. Cases attributed to Cryptosporidium spp. were more severe and required hospitalization. In the intention-to-treat population, VE was estimated to be 43.9% before and 46.5% after adjustment for co-infections; in the per-protocol population, VE was 46.7% before and 49.1% after adjustments. Rotavirus continued to be the leading cause of severe GE in this age group. The adjusted VE estimates obtained did not support co-infections as a major cause of lower vaccine performance in low- and middle-income countries.

Warty carcinoma of the penis: A clinicopathological study from South India.

AIMS: There are few studies on the pathology of warty carcinoma (WC) of the penis and these have been from South America. Penile cancers are not uncommon in India. We reviewed the frequency of subtypes of penile squamous carcinoma (SC) and the pathological features and outcome of WC when compared to squamous carcinoma-not otherwise specified (SC-NOS). We also compared the clinicopathological features of WC in our series with those published earlier. MATERIALS AND METHODS: We studied 103 cases of penile cancers over 6 years. Cases were classified into different subtypes according to established histologic criteria. Clinicopathologic features were studied in detail and compared among the different subtypes, especially between WC and SC-NOS. The patients were followed-up and disease free survival in months was noted. RESULTS: SC-NOS constituted 75.7% of all penile cancer cases in our series. The frequency of other subtypes was WC: 9.7%, verrucous: 3.9%, basaloid type and papillary type: 0.97% each, and mixed types 8.7%. The average tumor size and depth of invasion did not differ significantly between the two subtypes. Frequency of lymphovascular emboli and percentage of lymph node metastasis in WC (30 and 10%) were lesser than in SC-NOS (49.37 and 26.58%), respectively. There were no recurrences after partial penectomy in the WC subtype. In the SC-NOS type, three cases had recurrence after partial/total penectomy. CONCLUSION: Warty carcinoma constitutes nearly 10% of all penile squamous cell cancers. These patients seem to have a less aggressive behavior than SC-NOS.

Rural South Indian spirometry values show wide variation compared to existing prediction equations.

Background and Objective: India, a highly heterogeneous country, has no common reference standards for predicting spirometry values, with very few recent studies from south India. This study aimed to create reference equations for rural south Indian adults, based on a population-based survey in Vellore, south India and compare it with other equations from India. Methods: The data from 583 non-smoking, asymptomatic participants (30 years and older) from a spirometry-based survey for airflow obstruction (rural Vellore, 2018), were used to develop equations for FEV1, FEV1/FVC, and FVC. The dataset was divided for development (70%) and validation (30%), by gender. Differences between observed and predicted values were assessed using the new equations and comparisons made with other equations from India. Results: Predictions with Vellore rural equations were closest to the previous south Indian equations from urban Bangalore. However, the Bangalore equations led to overestimation of FVC values in males, and of both FEV1 and FVC values in females. Using the rural Vellore equations also led to a higher percent of males being classified as having airflow obstruction, compared to the Bangalore equations which underestimated airflow obstruction in this rural population. Comparison with previously derived Indian equations from other parts of the country showed pronounced variations. Conclusions: Our study reiterates the need for representative rural and urban studies of adults from various parts of India, to obtain region specific reference equations, given the wide variations in spirometry values in "normal" individuals, due to social heterogeneities of the Indian population and resulting complexities in defining normal.

A possible simplification for the estimation of area under the curve (AUC0₋12) of enteric-coated mycophenolate sodium in renal transplant patients receiving tacrolimus.

Enteric-coated mycophenolate sodium (EC-MPS) is widely used in renal transplantation. With a delayed absorption profile, it has not been possible to develop limited sampling strategies to estimate area under the curve (mycophenolic acid [MPA] AUC0₋12), which have limited time points and are completed in 2 hours. We developed and validated simplified strategies to estimate MPA AUC0₋12 in an Indian renal transplant population prescribed EC-MPS together with prednisolone and tacrolimus. Intensive pharmacokinetic sampling (17 samples each) was performed in 18 patients to measure MPA AUC0₋12. The profiles at 1 month were used to develop the simplified strategies and those at 5.5 months used for validation. We followed two approaches. In one, the AUC was calculated using the trapezoidal rule with fewer time points followed by an extrapolation. In the second approach, by stepwise multiple regression analysis, models with different time points were identified and linear regression analysis performed. Using the trapezoidal rule, two equations were developed with six time points and sampling to 6 or 8 hours (8hrAUC[0₋12exp]) after the EC-MPS dose. On validation, the 8hrAUC(0₋12exp) compared with total measured AUC0₋12 had a coefficient of correlation (r²) of 0.872 with a bias and precision (95% confidence interval) of 0.54% (-6.07-7.15) and 9.73% (5.37-14.09), respectively. Second, limited sampling strategies were developed with four, five, six, seven, and eight time points and completion within 2 hours, 4 hours, 6 hours, and 8 hours after the EC-MPS dose. On validation, six, seven, and eight time point equations, all with sampling to 8 hours, had an acceptable r with the total measured MPA AUC0₋12 (0.817-0.927). In the six, seven, and eight time points, the bias (95% confidence interval) was 3.00% (-4.59 to 10.59), 0.29% (-5.4 to 5.97), and -0.72% (-5.34 to 3.89) and the precision (95% confidence interval) was 10.59% (5.06-16.13), 8.33% (4.55-12.1), and 6.92% (3.94-9.90), respectively. Of the eight simplified approaches, inclusion of seven or eight time points improved the accuracy of the predicted AUC compared with the actual and can be advocated based on the priority of the user.

Toll-Like Receptors and Mannose Binding Lectin Gene Polymorphisms Associated with Cryptosporidial Diarrhea in Children in Southern India.

In low-resource settings, Cryptosporidium spp. is a common cause of diarrheal disease in children under the age of 3 years. In addition to diarrhea, these children also experience subclinical episodes that have been shown to affect growth and cognitive function. In this study, we screened polymorphisms in the promoter and exon1 regions of the mannose binding lectin 2 (MBL2) gene, as well as single nucleotide polymorphisms (SNPs) described in toll-like receptors (TLR) TLR1, TLR2, TLR4, and TLR9 and TIR domain-containing adaptor protein (TIRAP) genes among children with cryptosporidial diarrhea (cases) and children who only experienced asymptomatic (subclinical) cryptosporidiosis (controls). Among the polymorphisms screened, the variant allele B at codon 54 (rs1800450) of the MBL2 gene was associated with susceptibility to cryptosporidial diarrhea (odds ratio [OR] = 2.2, 95% confidence interval [CI] 1.1-4.5). When plasma MBL levels were compared, 72% of cases were found to be deficient compared with 32% among controls (OR = 5.09). Among TLR polymorphisms screened, multivariate analysis showed that heterozygous genotypes of TLR4 896A/G (rs4986790, OR = 0.33, 95% CI: 0.11-0.98) and TIRAP 539 C/T (rs8177374, OR = 0.19, 95% CI: 0.06-0.64) SNPs were associated with protection from cryptosporidial diarrhea. Although not statistically significant, these findings suggest that polymorphisms of MBL2 and TLR genes influence susceptibility to symptomatic cryptosporidial diarrhea even in settings with high exposure levels. Further studies to validate these findings in a larger cohort and to understand the role of these polymorphisms in mediating innate and adaptive immune responses to cryptosporidial infection are necessary.

A reliable limited sampling strategy for the estimation of mycophenolic acid area under the concentration time curve in adult renal transplant patients in the stable posttransplant period.

In renal transplant patients, there is an established relationship between mycophenolate area under the curve and clinical outcome. The authors have developed and validated a limited sampling strategy to estimate mycophenolic acid area under the curve to 12 hours (MPA AUC0-12) in a stable renal transplant Indian population prescribed a formulation of mycophenolate mofetil (Mofilet) along with prednisolone and tacrolimus. Intensive pharmacokinetic sampling was performed in 29 patients to measure mycophenolate concentration from trough to 12 hours postdose. Subsets of different timed concentrations against total measured 12-hour area under the curve were analyzed by linear regression. Three models were identified and linear regression analysis done. After all subset regression analysis, three, four, and five time point limited sampling strategies (LSS) were developed having correlation coefficients above 0.92. Validation of the models was performed using the jackknife method and their predictive performances were tested. After validation, the correlation coefficients for all three models were above 0.901. The five-point LSS had the best predictive performance with a bias (95% confidence interval) of 0.67% (-3.45 to 4.79) and mean precision 7.73%. In all patients except one, the five-point LSS estimation for total area under the curve was within +/- 20% of the total measured AUC0-12. Trough concentration had a significant correlation with AUC0-12 (r = 0.69). However, if dosing in routine clinical practice was adjusted based only on trough concentration, 41% of our patients would require a different dose compared with monitoring using AUC0-12. The five-point LSS uses half-hourly samples from trough to 1.5 hour postdose with an additional sample at 3 hours. Ninety-three percent of our patients had a Cmax within 1.5 hour and inclusion of all the time points up to1.5 hour gave a better estimate of AUC0-12. This model simplifies area under the curve measurement with high precision in stable adult renal transplant patients.

Mycophenolic acid estimation by pooled sampling: a novel strategy.

The aim of the study was to determine the reliability of estimating area under the curve from 0 to 6 hours (AUC0-6) of mycophenolic acid (MPA) by pooling the blood samples from different sampling time points. Eighty 6-hour concentration-time profiles were obtained from 68 patients on mycophenolate mofetil and the MPA AUC0-6 was calculated. In the pooled strategy, each of the equally spaced time point samples was pooled into two samples. Two rectangles were created instead of multiple trapezoids and the sum of their areas equal to the MPA AUC0-6. The linear correlation (r), intraclass correlation, bias, and precision were calculated between the pooled MPA AUC0-6 and the MPA AUC0-6 derived from measurements at different time points. Pharmacokinetic profiles of an additional 20 patients were obtained to study the possibility of using fewer time points to create a single pooled sample to obtain MPA AUC0-6. The linear correlation (r) and intraclass correlation between pooled and measured MPA AUC0-6 was 0.982 and 0.979, respectively. There was a highly significant correlation (r) of 0.978 between the pooled versus measured for both MPA AUC0-3 and MPA AUC3-6. The mean bias and precision (95% confidence interval) for pooled with total measured MPA AUC0-6 was -6.4% (-7.8% to -4.94%) and 7.37% (6.21%-8.54%), respectively. The pooled sample approach using only five time points to estimate MPA AUC0-6 had an unacceptable bias and precision. Pooling 10 samples to a set of two samples gave a highly accurate measure of MPA AUC0-6. The advantages for a central laboratory are the high throughput of samples and the transportation of only two specimens from other centers, all of which leads to a reduction in cost. This approach is extremely useful for studies aimed at examining the bioavailability of mycophenolate mofetil in different ethnic populations within India.

Time to debridement in open high-grade lower limb fractures and its effect on union and infections: A prospective study in a tropical setting.

PURPOSE: To prospectively evaluate whether time to debridement has any correlation with union, infection, and quality of life in high-grade lower limb fractures in a tropical setting. METHODS: A prospective cohort study was conducted at a tertiary care center in South India. Two hundred fifty-four adult skeletally mature patients with 301 grade 3 fractures involving the femur, tibia, or fibula were recruited. The cohort was empirically divided into two groups (early and late) based on the time to debridement (less than or more than 12 h from injury). OUTCOME: The primary outcome was nonunion. Secondary outcomes were deep infection rates and patients' quality of life. Short form-36 (SF-36) and short musculoskeletal functional assessment (SMFA) questionnaires were also used. Patients were followed up for 9 months. RESULTS: The follow-up rate was 93%. The late group had a significantly higher risk of nonunion (odds ratio(OR): 6.5, 95% confidence interval (CI): 2.82-14.95) and infections (OR: 6.05, 95% CI: 2.85-12.82). There was a 4% increase in the infection risk for each hour of delay for the initial 50 h (p < 0.0001). SF-36 and SMFA scores were superior in the early group (p < 0.0001). CONCLUSION: The study contradicts findings reported in the literature from the West. Our study was in agreement with our hypothesis and proved that debridement within 12 h resulted in significantly lower rates of nonunion and infections and an overall improved quality of life in high-grade open lower limb fractures in a developing country. LEVEL OF EVIDENCE: Level II. TRIAL REGISTRATION: German Clinical Trials Register DRKS00015186.

Incidence and risk factor evaluation of exposure keratopathy in critically ill patients: a cohort study.

PURPOSE: Recent emphasis on eye care in intensive care unit (ICU) patients has translated to eye assessment being part of routine care. In this setting, we determined the incidence, risk factors, and resolution time of exposure keratopathy. METHODS: In this prospective cohort study, 301 patients were examined within 24 hours of ICU admission and subsequently daily by an ophthalmologist till death or discharge. Eyelid position, conjunctival and corneal changes, treatment, and outcome data were collected. RESULTS: Admission diagnoses included febrile illnesses (35.2%) and respiratory failure (32.6%); 84.1% were ventilated. Forty-nine patients had exposure keratopathy (bilateral = 35, unilateral = 14) at admission; 35 patients developed new onset keratopathy (incidence 13.2%) 4.6 ± 2.6 days after ICU admission. In 67 patients, keratopathy was mild (punctate epithelial erosions). Macroepithelial defects (n = 9), stromal whitening with epithelial defect (n = 3), and stromal scar (n = 3) were infrequent. None developed microbial keratitis. On multivariate logistic regression analysis, eyelid position (odds ratio, 2.93; 95% confidence interval, 1.37-6.25), and ventilation duration (odds ratio, 1.11; 95% confidence interval, 1.04-1.19) were strongly associated with the development of keratopathy after ICU admission. Keratopathy resolved in 3.6 ± 4.5 days. CONCLUSIONS: Severe exposure keratopathy is infrequent in a protocolized ICU setting. Eyelid position and duration of ventilation are associated with exposure keratopathy.