Tracing geochemical sources and health risk assessment of uranium in groundwater of arid zone of India.

Water quality degradation and metal contamination in groundwater are serious concerns in an arid region with scanty water resources. This study aimed at evaluating the source of uranium (U) and potential health risk assessment in groundwater of the arid region of western Rajasthan and northern Gujarat. The probable source of vanadium (V) and fluorine (F) was also identified. U and trace metal concentration, along with physicochemical characteristics were determined for 265 groundwater samples collected from groundwater of duricrusts and palaeochannels of western Rajasthan and northern Gujarat. The U concentration ranged between 0.6 and 260 µg L-1 with a mean value of 24 µg L-1, and 30% of samples surpassed the World Health Organization's limit for U (30 µg L-1). Speciation results suggested that dissolution of primary U mineral, carnotite [K2(UO2)2(VO4)2·3H2O] governs the enrichment. Water-rock interaction and evaporation are found the major hydrogeochemical processes controlling U mineralization. Groundwater zones having high U concentrations are characterized by Na-Cl hydrogeochemical facies and high total dissolved solids. It is inferred from geochemical modelling and principal component analysis that silicate weathering, bicarbonate complexation, carnotite dissolution, and ion exchange are principal factors controlling major solute ion chemistry. The annual ingestion doses of U for all the age groups are found to be safe and below the permissible limit in all samples. The health risk assessment with trace elements manifested high carcinogenic risks for children.

Serum Electrolyte, Serum Calcium and Blood Sugar Status in Severe Acute Malnutrition and Their Relationship with Edema, Vomiting and Diarrhea.

Severe acute malnutrition (SAM) is the most severe form of protein energy malnutrition (PEM). Few studies found serum electrolyte, serum calcium level changes as important factors of poor outcome. Hypoglycemia is already established as a risk factor for death in severe acute malnutrition. Edema, diarrhea and vomiting are commonly present in severe acute malnutrition which has impact on electrolyte balance and blood sugar level in healthy children. Their impact in severe acute malnutrition is not clearly established. This cross sectional descriptive study was conducted in Department of Pediatrics, MMCH from March 2018 to October 2019 to estimate serum electrolyte, serum calcium and random blood sugar level in severe acute malnutrition and their relationship with edema, vomiting and diarrhea. Forty-one (41) cases of SAM were enrolled in this study. Test samples were collected before starting the treatment. Case record form was used to collect information. Cases were divided into Group A and Group B based on the presence or absence of vomiting or diarrhea, respectively. Again, all cases were divided into Group C and Group D based on presence or absence of edema, respectively. Data were analyzed using IBM SPSS statistics version 23. Mean age was 9.71±10.4 months with 85.36% having age less than 1 year. Twenty-four (58.5%) were male and 17(41.5%) were female. Parents had low level of education with 48.8% mother and 51.2% father having primary education or no education. Higher number of serum electrolyte, serum calcium and blood sugar were found with hyperglycemia present in 29.3%, hypocalcemia in 22%, hypokalemia in 22% and hyponatremia in 19.5% cases. Hypokalemia was present more in SAM with vomiting or diarrhea (p=0.008). Other disturbances do not vary on presence or absence of edema and vomiting or diarrhea. Result of the present study shows hypokalemia is associated with SAM with vomiting/diarrhea. Hypocalcemia, hyperglycemia, hyponatremia and hypernatremia were also present in high number. These changes should be detected early and treated accordingly.

Efficacy of Nebulized Hypertonic Saline (3%) Versus Normal Saline and Salbutamol in Treating Acute Bronchiolitis in A Tertiary Hospital: A Randomized Controlled Trial.

Acute bronchiolitis is a viral respiratory illness of infants and young children that occurs in the first two years of life. It is a major cause of hospital admissions in Bangladesh. Management of bronchiolitis is a great challenge for the pediatrician both in the outpatient and inpatient department. Because mainstay of treatment options are usually supportive like cool humidified oxygen, fluids, bronchodilators, epinephrine and corticosteroids. A number of agents have been proposed as adjunctive therapies, but their effects are controversial. Nebulized hypertonic saline (3%) has been reported to have some benefit in recent studies. So the objective of this study was to compare the efficacy of nebulized 3% hypertonic saline (HS) with salbutamol and normal saline (0.9%) nebulization in children with acute bronchiolitis. A double-blind randomized controlled trial was conducted in the Department of Paediatrics, Mymensingh Medical College Hospital, Bangladesh from November 2015 to October 2016. A total of 100 children aged one month to two years with acute bronchiolitis admitted in the Pediatric wards of MMCH were included in the study and were randomly assigned to either 3% nebulized hypertonic saline (n=50) or to 0.9% nebulized isotonic saline with salbutamol solution (n=50). The main outcome variables were clinical severity score, length of hospital stay, duration of oxygen therapy and oxygen saturation (SpO2). The therapy was repeated three times on every hospitalization day and the outcome was evaluated two times daily (12 hourly) for 60 hours. Mean duration of oxygen therapy in study group was 33.6±21.7 hours and in control group was 36.8±22.5 hours. But their difference was not statistically significant (p>0.05). The mean clinical severity score and mean oxygen saturation of the entire study patients in both groups decreased and increased respectively during hospital stay. There was significant difference of mean clinical severity score and oxygen saturation between admission and follow up-5 in each group (p<0.001). But their difference between two groups was not statistically significant (p>0.05). Mean duration of hospital stay was 2.91±1.54 days in study group and 3.09±1.85 days in control group. But their difference between two groups was not statistically significant (p>0.05). So in acute bronchiolitis nebulized hypertonic saline (3%) is as effective as normal saline (0.9%) and salbutamol nebulization.

Etiology of Chronic Abnormal Uterine Bleeding According to the FIGO's PALM-COEIN Classification in Bangladeshi Women of Reproductive Age: A Cross-Sectional Study.

Chronic abnormal uterine bleeding (AUB) is common, but there is a lack of standardized methods for investigating and etiological categorization of AUB. The PALM-COEIN classification system of AUB is getting important to overcome this issue. This cross-sectional study was conducted from January 2019 to December 2019 at Mymensingh Medical College Hospital, Mymensingh, Bangladesh, to determine the causes of AUB in women of the reproductive age group and categorize the causes of AUB as per the PALM-COEIN classification. A total of 380 women with chronic AUB were evaluated. The distribution of PALM-COEIN causes of AUB were AUB-P (1.8%), AUB-A (9.2%), AUB-L (13.2%), AUB-M (5.8%), AUB-C (1.1%), AUB-O (24.7%), AUB-E (1.6%), AUB-I (6.6%), and AUB-N (36.1%). The participants' mean age was 29.6 (±10.5) years, the majority (78.2%) of them was married, only a few (9.5%) had comorbid diseases, including hypertension (HTN) (1.1%), diabetes mellitus (DM) (5.3%), and hypothyroidism (8.7%). Women in the AUB-M classification had higher age than others; anemia was more prevalent in the AUB-P group, the AUB-O group had the highest TSH levels and hypothyroidism frequency. The PALM-COEIN classification helps ascertain the cause of AUB practically and should be used in routine clinical practices to manage these patients better.

Prevalence of Hepatitis B Virus Infection among Children with Liver Disease Admitted In Mymensingh Medical College Hospital.

Hepatitis B virus infection is an important cause of liver disease. Hepatitis B Virus may present with varying degree of severity. In older children, 5-10% cases leading to chronic liver disease, cirrhosis and hepatocellular carcinoma. This descriptive cross sectional study was done to assess the prevalence of Hepatitis B Virus infection among hospitalized children with liver disease in pediatric department of Mymensingh Medical College Hospital, Bangladesh from December 2015 to October 2016. All the children of both sexes having age between six months to twelve years admitted in the pediatric ward with acute or chronic liver disease were included in this study by purposive sampling. A written consent was obtained from legal guardian of children before inclusion. Ethical clearance was obtained from competent authority. A detailed history was taken from parents in each case according to pre-designed questionnaire about demography of the patients and the risk factors of the liver disease. A thorough clinical examination and available relevant investigations like serological testing for HBV infection was done in all patients. We had figure out the seropositivity of HBV among patients having liver disease by doing HBsAg and Anti-HBc IgM. Progress of the patient was monitored by daily clinical examinations and by investigating HBsAg and Anti-HBc IgM. Finally data analysis was done by SPSS version 21.0. Among total 100 patients most (44%) patients were in 7-10 years old and most (62%) of the participants were male. Acute liver disease was 58% cases and chronic liver disease was 42% cases. HBsAg was positive in 1 case among acute liver disease and 5 cases among chronic cases. Total 6 (six) patients were found positive for HBsAg. Anti HBc IgM was positive in 4 patients among acute liver disease. Among these Anti HBc IgM positive (4) patients only one had both HBsAg and Anti HBc IgM positive. So, four patients were confirming suffered from acute viral hepatitis because they had anti HBc IgM positive. On the contrary 5 patients suffered from chronic hepatitis by hepatitis B because they were only HBsAg positive. So, in this study 9 patients (9%) were confirming suffered from HBV infection. Possible transmission factors of hepatitis B were history of (H/O) blood transfusion/trauma/parenteral injection, H/O umbilical sepsis, H/O maternal illness/infection during pregnancy. HBV still is a major cause of morbidity. All the children with liver disease should be routinely tested for HBV.

Stress Hyperglycemia and Stroke Outcome in Patients with Acute Stroke.

Stroke is leading cause of death world wide, after coronary artery disease and cancer. A high proportion of patients suffering from an acute stress such as stroke or myocardial infarction may develop hyperglycemia, even in the absence of a preexisting diagnosis of diabetes. An observational comparative study was carried out at the Department of Neurology and Medicine, Mymensingh Medical College, Mymensingh, Bangladesh from July 2011 to June 2013 among purposively selected ninety-three patients with a view to assess the outcome of stress hyperglycemia on acute stroke. Data were collected through interview, physical examinations & laboratory investigations by using case record form. Statistical analysis was performed using SPSS (Statistical package for social science) version 17. The mean age of this study was 59.04±15.01 years in the hyperglycemic group and 62.06±13.81 years in the normoglycemic group. The male female ratio in the Hyperglycemic and normoglycemic group was 2.12:1 and 2.44:1 respectively. Smoker was 48.8% in the hyperglycemic group and 52% in the normoglycemic group. 70% of the Hyperglycemic group and 66% of the normoglycemic were found hypertensive. Mean±SD blood glucose level was found 11.86±0.58mmol/L in the Hyperglycemic group and 6.50±1.55mmol/L in the normoglycemic group. Mean HbAlc were 6.14±0.56 in hyperglycemic group and 5.29±0.54 in normoglycemic group. Stroke severity score were 21.79±11.85 in Hyperglycemic and 28.64±9.53 in normoglycemic group on admission. Functional outcome was measured on discharge & at the end of 4th weeks of every patient by Glasgo Outcome Scale (GOS). The study also suggests that stress hyperglycemia is an important risk factor of poor stroke outcome.

Towards the geometric structure of small supported Au9 clusters on Si.

Ultra-small clusters containing few atoms are of high interest in both fundamental research and applications due to their specific functional, magnetic or chemical properties which depend on size and composition. The experimental results of the morphology of the size-selected clusters, consisting of few atoms can be an ideal benchmark for sophisticated theoretical models. With this motivation we have investigated the geometrical structure of mass-selected Au9 clusters deposited on a silicon substrate prepared by soft-landing conditions. We present results obtained experimentally by Grazing-Incidence Small-Angle X-ray Scattering (GISAXS). Considering the ultra-small size of the clusters and small quantities of material on the surface, we combined advanced techniques which allowed us to investigate the surface structure of the sample. The resulting structural sizes are in concordance with cluster theory. Using a model-based approach, the advanced X-ray techniques allow for understanding how to resolve the possible cluster structure, identify optimal experimental conditions and obtain the probable morphological information which is challenging to be obtained otherwise.

High Wall Motion Score Index after Acute Myocardial Infarction is Associated with Worse In-Hospital Outcome.

Myocardial Infarction is a major cause of death and disability worldwide. The incidence of coronary heart disease is high and second most cause of death after cancer. This prospective study conducted on 100 patients admitted with first attack of acute myocardial infarction in the department of Cardiology in Mymensingh Medical College Hospital, Mymensingh, Bangladesh from July 2012 to June 2013 who were observed 3 to 8 days of hospital stay without doing further echocardiography and evaluated the relationship between echocardiographic wall motion score index (WMSI) assessed within 24 hours of admission and in-hospital outcomes. Mean age was 53.24±10.17 years in WMSI <2 and 55.58±12.68 years in WMSI ≥2 groups; difference was statistically non-significant (p>0.05). In both groups, males were predominant sufferer. Male-female ratio was 3.55:1 and the difference was statistically non-significant (p>0.05). As a risk factor, smoking was significantly higher in both groups but the difference was not statistically significant (p>0.05) between groups. Hypertension was 34(49.28%) cases in WMSI <2 and 13(41.93%) cases in WMSI ≥2 group; difference was not statistically significant (p>0.05). Diabetes mellitus was 13(18.84%) cases in WMSI <2 and 16(51.61%) cases in WMSI ≥2 group that was statistically significant (p<0.05). Dyslipidemia was 28(40.58%) cases in WMSI <2 group and 23(74.19%) cases in WMSI ≥2 group that was statistically significant (p<0.05). Site of involvement of MI in WMSI <2 group were 39(56.52%) cases AMI (Anterior) and 30(43.48%) cases AMI (Inferior). In WMSI ≥2 group, AMI (Anterior) were 29(93.55%) and AMI (Inferior) were 02(6.45%). It revealed that AMI (anterior) was significantly higher in WMSI ≥2 group and AMI (Inferior) was significantly higher in WMSI <2 group. Heart failure class (Killip class) increases with the increasing of WMSI. In Killip class-I, 4(5.80%) were WMSI <2 and 01(3.23%) was WMSI ≥2 (p>0.05). In Killip class-II, 8(11.59%) were WMSI <2 and 02(6.45%) were WMSI ≥2 (p>0.05). In Killip class-III, 4(5.80%) were WMSI <2 and 13(41.94%) were WMSI ≥2 (p<0.05). In Killip class-IV, 2(2.89%) were WMSI <2 and 05(16.13%) were WMSI ≥2 (p<0.05) that was statistically significant. Arrhythmia was 14(20.29%) cases in WMSI <2 group and 13(41.94%) cases in WMSI ≥2 group that was statistically significant (p<0.05). Death was 2(2.90%) cases in WMSI <2 and 07(22.58%) cases in WMSI ≥2 group that was statistically significant (p<0.05). Early mortality rate was greater in patients with both WMSI ≥2 and a higher Killip's class. The higher the WMSI determined within 24 hours of admission, the worse the in-hospital outcome. Echocardiography is an affordable and readily available technique, which may be used to identify and stratify the risk following acute MI.

[18F]-Sodium Fluoride PET MR-Based Localization and Quantification of Bone Turnover as a Biomarker for Facet Joint-Induced Disability.

Our aim was to prospectively evaluate the relationship between low back pain-related disability and quantitative measures from [18F]-sodium fluoride ([18F]-NaF) MR imaging. Six patients with facetogenic low back pain underwent dynamic [18F]-NaF PET/MR imaging. PET metrics were correlated with clinical measures and MR imaging grading of lumbar facet arthropathy. A significant positive correlation was observed between maximum facet joint uptake rate and clinical disability (P < .05). These data suggest that dynamic [18F]-NaF PET may serve as a useful biomarker for facetogenic disability.

A Retrospective Comparative Study of Concomitant Chemoradiotherapy followed by Adjuvant Temozolomide Versus Radiotherapy Alone In Newly Diagnosed Glioblastoma Multiforme - An Experience at Radium Institute, Patna Medical College and Hospital, India.

INTRODUCTION: Glioblastoma Multiforme (WHO grade IV glioma) still remains a dreadful diagnosis in oncology with the median survival ranging between 12 to 17 months, despite the recent advances in its management. It is the most common malignant primary tumour in adults(13). The standard of care is Maximal Safe Resection followed by Concomitant ChemoRadiotherapy. METHODS: During the period 2006 to 2010 at Radium Institute, Patna Medical College and Hospital (PMCH) in India, a study was conducted on 37 newly diagnosed GBM cases in which the control-arm (c-arm) received Conventional Radiotherapy (60Gy/30#) only whereas the study arm (s-arm) received Concomitant Chemoradiotherapy followed by Adjuvant Temozolomide. RESULTS: The median survival was 15.4 months in the s-arm as compared to 12.4 months in the c-arm. The OS showed a significant improvement with p-value of 0.05 and PFS also showed a benefit with a p-value of 0.005. CONCLUSION: The results were encouraging with improvement in OS as well as PFS in the s-arm and were at par with the other similar studies conducted in different parts of the world.

Role of taxanes in the treatment of advanced NHL patients: A randomized study of 87 cases.

UNLABELLED: NHL is a highly chemo-sensitive as well as radiosensitive disease. From May 2005 to June 2010, 87 patients were randomised into 2 arms. The control arm received the standard CHOP regimen + IFRT, whereas the study arm received Paclitaxel, 135/m2 additionally. The results showed a better Overall Response (87% vs 78%) in the study arm. The 3yr and 5yr overall survival were significantly better in the study arm (89% vs 77%, p- value <0.05; 83% vs 67%, p-value <0.05). However, the incidence and severity of the side effects, haematological and non- haematological were enhanced but manageable in the study arm. KEYWORDS: Taxanes, Paclitaxel, Non Hodgkin's Lymphoma.

Anti-C reactive protein antibodies in Indian patients with systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) is characterized by over production of autoantibodies. C-reactive protein (CRP) is a phylogenetically highly conserved plasma protein that participates in the systemic response to inflammation. Anti-CRP antibodies might have biological functions of pathogenetic interest in SLE. We evaluated anti-CRP antibodies in Indian SLE patients and their association with anti-dsDNA antibodies and complement levels (C3 and C4). One hundred SLE patients diagnosed according to the American College of Rheumatology criteria were included. Disease activity was assessed using SLE disease activity index (SLEDAI). Anti-CRP autoantibodies were detected by enzyme linked immunosorbent assay. Anti-dsDNA antibodies were detected by indirect immunofluroscence test (Euroimmun Lubeck, Germany). High sensitivity CRP and complement levels (C3, C4) were detected using a Nephelometer. (BN ProSpec, Dade Behring, Germany). Anti-CRP antibodies were detected in 26% of SLE patients. Mean age of disease onset among anti-CRP positives was 22.4 ± 7.5, and 26.6 ± 9.3 years among anti-CRP negatives (P > 0.05). Anti-dsDNA positivity was significantly higher among anti-CRP positives (32.7%) as compared to anti-CRP negatives (16%) (P = 0.00519). No statistically significant difference was observed in SLEDAI scores of anti-CRP positive group and anti-CRP negative group (P > 0.05). We observed a positive correlation between anti-CRP antibodies and anti-dsDNA antibodies.

Identification of candidate sialome components expressed in ixodid tick salivary glands using secretion signal complementation in mammalian cells.

Ixodid ticks manipulate mammalian host pathways by secreting molecules from salivary glands. Novel cDNAs containing functional secretion signals were isolated from ixodid tick salivary glands using a signal sequence trap. Only 15/61 Rhipicephalus appendiculatus and 1/7 Amblyomma variegatum cDNAs had significant identity (< 1e-15) to previously identified sequences. Polypeptides that may interact with host pathways included a kinase inhibitor. Two proteins encoded homologues of the yolk protein vitellogenin and seventeen contained glycine-rich motifs. Four proteins without sequence matches had conserved structural folds, identified using a Threading algorithm. Predicted secretion signals were between fifteen and fifty-seven amino acids long. Four homologous polymorphic proteins contained conserved (26/27 residues) signal peptides. Ten functional tick secretion signals could not be unambiguously identified using predictive algorithms.

Removal of ionic dyes from water by solvent extraction using reverse micelles.

Several methods (e.g., UV/H2O2 oxidation, adsorption, flocculation-precipitation) are normally employed to remove dye from water. A new technique based on liquid/liquid extraction using reverse micelles is proposed whereby recovery of solvent and reuse of dye is possible. Experiments were conducted by mixing a known quantity of dye in aqueous phase and solvent-containing surfactants in a simple mixer. The separation of solvent phase, containing encapsulated dye in reverse micelles, from aqueous phase due to gravity results in separation of dye from water. The removal of different ionic dyes (e.g., eosin yellow, methylene blue, malachite green, methyl orange, orange G) from aqueous phase in the presence of different cationic and anionic surfactants [e.g., sodium dodecylbenzene sulfonate, sodium bis(2-ethylhexyl) sulfosuccinate, hexadecyltrimethylammonium bromide, and cetyl pyridinium chloride] in different solvents (e.g., amyl alcohol, benzyl alcohol, methyl benzoate, and isooctane) were studied by conducting experiments. The percentage removal of dye from aqueous phase increases with the decrease in dye concentration or with the increase in surfactants concentration. Furthermore, the percentage COD removal of dye is increased with the increase in surfactant concentration. The nature of solvent has minimal effect on percentage removal of dye. The ratio of solventto aqueous phase volume required for the removal of dye decreases with the increase in surfactant concentration. It is possible to back-extract dye into aqueous phase and recover solvent by using counterionic surfactants. The separation of aqueous phase from the aqueous-phase solvent dispersion is faster for amyl alcohol as compared to benzyl alcohol and methyl benzoate. A theoretical model based on ion-exchange reaction between surfactants and dye is used to analyze the experimental data.

Removal of organic dyes from water by liquid-liquid extraction using reverse micelles.

In the present work, solvent extraction using reverse micelles is proposed for the removal of organic dyes from water. In this approach, the dye is solubilized in the aqueous core of the reverse micelles, which are present in the organic phase. The organic phase is subsequently separated from the aqueous phase leading to signifi-cant removal of dye. Experimental results reveal that the electrostatic interaction between the oppositely charged surfactant head group present in the reverse micelles and the dye molecule plays a key role in the separation. The removal of the anionic methyl orange dye from water is carried out in the presence of cationic hexadecyltrimethyl ammonium bromide surfactant, whereas the removal of the cationic methylene blue dye is carried out in the presence of anionic sodium dodecylbenzene sulfonate surfactant. Amyl alcohol is used as the solvent. The influence of parameters such as dye concentrations, surfactant concentrations, pH, and KCl and NaBr concentrations on the percentage removal of dye was studied. The percentage removal of dye is decreased with the increase in dye concentration in the feed. The increase in surfactant concentration resulted in higher dye removal, because more reverse micelles could be hosted in the organic phase. The increase in aqueous phase pH resulted in enhanced removal of methyl orange from water, while in the case of methylene blue the percentage removal decreased. The increase in KCl and NaBr concentrations resulted in decreased percentage removal of methylene blue, whereas the percentage removal of methyl orange was increased. The effect of pH and salt concentration is explained based on charge transfer mechanism and electrostatic interactions and dye-surfactant complex formation.

Work of breathing during constant- and variable-flow nasal continuous positive airway pressure in preterm neonates.

BACKGROUND: Constant-flow nasal continuous positive airway pressure (NCPAP) often is used in preterm neonates to recruit and maintain lung volume. Physical model studies indicate that a variable-flow NCPAP device provides more stable volume recruitment with less imposed work of breathing (WOB). Although superior lung recruitment with variable-flow NCPAP has been demonstrated in preterm neonates, corroborating WOB data are lacking. OBJECTIVE: To measure and compare WOB associated with the use of variable-flow versus constant-flow NCPAP in preterm neonates. METHODS: Twenty-four preterm infants who were receiving constant-flow NCPAP (means, SD) and had birth weight of 1024 +/- 253 g, gestational age of 28 +/- 1.7 weeks, age of 14 +/- 13 days, and FIO(2) of 0.3 +/- 0.1 were studied. Variable-flow and constant-flow NCPAP were applied in random order. We measured changes in lung volume and tidal ventilation (V(T)) by DC-coupled/calibrated respiratory inductance plethysmography as well as esophageal pressures at NCPAP of 8, 6, 4, and 0 cm H(2)O. Inspiratory WOB (WOB(I)) and lung compliance were calculated from the esophageal pressure and V(T) data using standard methods. WOB was divided by V(T) to standardize the results. RESULTS: WOB(I) decreased at all CPAP levels with variable-flow NCPAP, with a maximal decrease at 4 cm H(2)O. WOB(I) increased at all CPAP levels with constant-flow CPAP. Lung compliance increased at all NCPAP levels with variable-flow, with a relative decrease at 8 cm H(2)O, whereas it increased only at 8 cm H(2)O with constant-flow NCPAP. Compared with constant-flow NCPAP, WOB(I) was 13% to 29% lower with variable-flow NCPAP. CONCLUSION: WOB(I) is decreased with variable-flow NCPAP compared with constant-flow NCPAP. The increase in WOB(I) with constant-flow NCPAP indicates the presence of appreciable imposed WOB with this device. Our study, performed in neonates with little lung disease, indicates the possibility of lung overdistention at CPAP of 6 to 8 cm H(2)O with the variable-flow device. Further study is necessary to determine the efficacy of variable-flow NCPAP in neonates with significant lung disease and its use over extended periods of time.continuous-flow and variable-flow NCPAP, work of breathing, premature neonates, lung compliance.

Lung recruitment and breathing pattern during variable versus continuous flow nasal continuous positive airway pressure in premature infants: an evaluation of three devices.

OBJECTIVE: To determine whether lung volume changes and breathing pattern parameters differ among 3 devices for delivery of nasal continuous positive airway pressure (CPAP) in premature infants. METHODS: Thirty-two premature infants receiving nasal CPAP for apnea or mild respiratory distress were enrolled. Birth weight was (mean +/- standard deviation) 1081 +/- 316 g, gestational age 29 +/- 2 weeks, age at study 13 +/- 12 days, and fraction of inspired oxygen (FIO(2)) at study.29 +/-.1. Three devices, applied in random order, were studied in each infant: continuous flow nasal CPAP via CPAP prongs, continuous flow nasal CPAP via modified nasal cannula, and variable flow nasal CPAP. After lung recruitment to standardize volume history, changes in lung volume (DeltaV(L)) were assessed at nasal CPAP of 8, 6, 4, and 0 cm H(2)O using calibrated direct current-coupled respiratory inductance plethysmography. RESULTS: DeltaV(L) was significantly greater overall with the variable flow device compared with both the nasal cannula and CPAP prongs. However, DeltaV(L) was not different between the cannula and the prongs. Respiratory rate, tidal volume, thoraco-abdominal asynchrony, and FIO(2) were greater with the modified cannula than for either of the other 2 devices. CONCLUSION: Compared with 2 continuous flow devices, the variable flow nasal CPAP device leads to greater lung recruitment. Although a nasal cannula is able to recruit lung volume, it does so at the cost of increased respiratory effort and FIO(2).

Detecting lung overdistention in newborns treated with high-frequency oscillatory ventilation.

Positive airway pressure (Paw) during high-frequency oscillatory ventilation (HFOV) increases lung volume and can lead to lung overdistention with potentially serious adverse effects. To date, no method is available to monitor changes in lung volume (DeltaVL) in HFOV-treated infants to avoid overdistention. In five newborn piglets (6-15 days old, 2.2-4.2 kg), we investigated the use of direct current-coupled respiratory inductive plethysmography (RIP) for this purpose by evaluating it against whole body plethysmography. Animals were instrumented, fitted with RIP bands, paralyzed, sedated, and placed in the plethysmograph. RIP and plethysmography were simultaneously calibrated, and HFOV was instituted at varying Paw settings before (6-14 cmH(2)O) and after (10-24 cmH(2)O) repeated warm saline lung lavage to induce experimental surfactant deficiency. Estimates of Delta VL from both methods were in good agreement, both transiently and in the steady state. Maximal changes in lung volume (Delta VL(max)) from all piglets were highly correlated with Delta VL measured by RIP (in ml) = 1.01 x changes measured by whole body plethysmography - 0.35; r(2) = 0.95. Accuracy of RIP was unchanged after lavage. Effective respiratory system compliance (Ceff) decreased after lavage, yet it exhibited similar sigmoidal dependence on Delta VL(max) pre- and postlavage. A decrease in Ceff (relative to the previous Paw setting) as Delta VL(max) was methodically increased from low to high Paw provided a quantitative method for detecting lung overdistention. We conclude that RIP offers a noninvasive and clinically applicable method for accurately estimating lung recruitment during HFOV. Consequently, RIP allows the detection of lung overdistention and selection of optimal HFOV from derived Ceff data.

Lung resistance and elastance in spontaneously breathing preterm infants: effects of breathing pattern and demographics.

Reported values of lung resistance (RL) and elastance (EL) in spontaneously breathing preterm neonates vary widely. We hypothesized that this variability in lung properties can be largely explained by both inter- and intrasubject variability in breathing pattern and demographics. Thirty-three neonates receiving nasal continuous positive airway pressure [weight 606-1,792 g, gestational age (GA) of 25-33 wk, 2-49 days old] were studied. Transpulmonary pressure was measured by esophageal manometry and airway flow by face mask pneumotachography. Breath-to-breath changes in RL and EL in each infant were estimated by Fourier analysis of impedance (Z) and by multiple linear regression (MLR). RL(MLR) (RL(MLR) = 0.85 x RL(Z) -0.43; r(2) = 0.95) and EL(MLR) (EL(MLR) = 0.97 x EL(Z) + 8.4; r(2) = 0.98) were highly correlated to RL(Z) and EL(Z), respectively. Both RL (mean +/- SD; RL(Z) = 70 +/- 38, RL(MLR) = 59 +/- 36 cm H(2)O x s x l(-1)) and EL (EL(Z) = 434 +/- 212, EL(MLR) = 436 +/- 210 cm H(2)O/l) exhibited wide intra- and intersubject variability. Regardless of computation method, RL was found to decrease as a function of weight, age, respiratory rate (RR), and tidal volume (VT) whereas it increased as a function of RR. VT and inspiratory-to-expiratory time ratio (TI/TE). EL decreased with increasing weight, age, VT and female gender and increased as RR and TI/TE increased. We conclude that accounting for the effects of breathing pattern variability and demographic parameters on estimates of RL and EL is essential if they are to be of clinical value. Multivariate statistical models of RL and EL may facilitate the interpretation of lung mechanics measurements in spontaneously breathing infants.