Estimation of instantaneous venous blood saturation using the Photoplethysmograph (PPG) waveform

Non-invasive estimation of regional venous saturation (SxvO2) using a conventional pulse oximeter could provide a means of obtaining clinically relevant information. This study was carried out in order to investigate the hypothesis that SxvO2 could be estimated by utilising the modulations created by positive pressure ventilation in the photoplethysmograph (PPG) signals. The modulations caused by the mechanical ventilator were extracted from oesophageal PPG signals obtained from 12 patients undergoing cardiothoracic surgery. The signals analysed in this work were acquired in a previous study. For the purpose of this analysis the raw PPG signal was considered to have three major components, ac PPG signal (cardiac related component), a static component or dc PPG signal (created mostly by the absorption of light by surrounding tissue) and the ventilator modulation component. These components were then used to estimate instantaneous arterial blood oxygen saturation (SpO2) and SxvO2 by utilising time-frequency analysis technique of smoothed-pseudo Wigner–Ville distribution (SPWVD). The results showed that there was no significant difference in the traditionally-derived (time-domain) arterial saturation and the instantaneous arterial saturation. However, the instantaneous venous saturation was found to be significantly lower than the estimated time-domain and instantaneous arterial saturation (P=<0.001, n=12)

FIR Filter Design for Removal of Ventilator Artefact in Oesophageal Photoplethysmographic Signals

The oesophagus has been found to be a reliable monitoring site for blood oxygen saturation (SpO2) in anaesthetised patients. Despite it being a very well perfused organ, it was not possible to estimate SpO2 in the lower to deep oesophagus due to movement artefact caused by the mechanical ventilator. This limitation made the measurements more difficult since the probe had to be placed carefully at a depth where the magnitude of the ventilator artefact was less than 30% of the oesophageal photoplethysmographic (PPG) amplitude. To overcome this limitation, two filters, a 384th order FIR Equiripple linear-phase filter and a 10th order Butterworth bandpass filter, were implemented and compared. The Equiripple filter performed better than the Butterworth filter in terms of attenuation and phase characteristics. This Equiripple filter achieved an attenuation of about 80 dB in the stopbands which significantly reduced the ventilator artefact without changing the morphology of the PPG signal. Such a filter should allow the monitoring of SpO2 within the whole length of the oesophagus

Modulation of finger photoplethysmographic traces during forced respiration: venous blood in motion?

Photoplethysmographic (PPG) signals were recorded from the fingers of 10 healthy volunteers during forced respiratory inspiration. The aim of this pilot study was to assess the effect of negative airway pressure on the blood volumes within the tissue bed of the finger, and the resultant modulation of PPG signals. The acquired signals were analysed and oxygen saturations estimated from the frequency spectra in the cardiac and respiratory frequency ranges. Assuming that respiratory modulation affects blood volumes in veins to a greater extent than in arteries, the local venous oxygen saturation was estimated. Estimated venous oxygen saturation was found to be 3.1% (±4.2%) lower than the estimated arterial saturation

Effect of spinning variables on packing density of cotton yarn

In this study, fibre distribution through the cross-sections of ring-spun yarns and their packing density values has been investigated to provide a better understanding of the internal structures of ring-spun yarns manufactured by changing different spinning variables. After the yarn manufacturing process, diameter, IPI index, uniformity index, single yarn strength, density and hairiness are tested and then evaluation of tests is done on the Minitab and Microsoft Excel. The impact of TPI, spindle speed, count, hairiness and diameter has been analyzed using yarn packing density as a response variable. The aim of present study is to produce a yarn with improved packing density so that the yarn properties could be predetermined. The study shows that the increase in yarn count, TPI and spindle speed increase the yarn packing density

Localizing introgression on the chromosome of rice by genomic in situ hybridization (GISH)

Genomic in situ hybridization was used to detect introgressed segment from Oryza australinesis onto the chromosomes of introgression line derived from the hybrid O. sativa x O. australinesis. Genomic DNA from Oryza australinesis was labeled with biotin and hybridized to the homologous sequences on the O. sativa chromosomes. The probe hybridization fluoresced green and non labeled O. sativa chromosomes appeared red or blue due to counterstaining with propidium iodide (PI) or 4,6-diamidino-2-phenylindole (DAPI). This differential painting of chromosomes unequivocally detected the introgressedsegment. Among the 200 cells analyzed, 6.5% of the cells showed&#160; hybridization signal. Signal appeared on one chromosome in 5%, on two homologous chromosomes in 1% and on sister chromatids in 0.5%of the cells. Hybridization was seen on the short arm of the chromosome 12 of the introgression line

Instantaneous venous oxygenation estimation using the Photoplethysmograph (PPG) waveform

In this study oesophageal photoplethysmograph data from eight patients under positive pressure ventilation were analysed in order to test the hypothesis that the modulations created by the ventilation in the AC Photoplethysmograph (PPG) signal could be used to estimate venous oxygen saturation. In order to estimate the instantaneous arterial and venous oxygen saturation Smoothed-pseudo Wigner-Ville Distribution (SPWVD) was utilised. The result from this study showed that there was no significant different in the conventional (time domain) arterial saturation and the instantaneous arterial saturation. However, the instantaneous venous oxygen saturation estimated with the ventilator modulation were significantly lower then the conventional arterial saturation (P=0.008) and also from the instantaneous arterial saturation (P=0.008)

Adjuvant chemotherapy with or without bevacizumab in patients with resected non-small-cell lung cancer (E1505): an open-label, multicentre, randomised, phase 3 trial.

BackgroundAdjuvant chemotherapy for resected early-stage non-small-cell lung cancer (NSCLC) provides a modest survival benefit. Bevacizumab, a monoclonal antibody directed against VEGF, improves outcomes when added to platinum-based chemotherapy in advanced-stage non-squamous NSCLC. We aimed to evaluate the addition of bevacizumab to adjuvant chemotherapy in early-stage resected NSCLC.MethodsWe did an open-label, randomised, phase 3 trial of adult patients (aged ≥18 years) with an Eastern Cooperative Oncology Group performance status of 0 or 1 and who had completely resected stage IB (≥4 cm) to IIIA (defined by the American Joint Committee on Cancer 6th edition) NSCLC. We enrolled patients from across the US National Clinical Trials Network, including patients from the Eastern Cooperative Oncology Group-American College of Radiology Imaging Network (ECOG-ACRIN) affiliates in Europe and from the Canadian Cancer Trials Group, within 6-12 weeks of surgery. The chemotherapy regimen for each patient was selected before randomisation and administered intravenously; it consisted of four 21-day cycles of cisplatin (75 mg/m2 on day 1 in all regimens) in combination with investigator's choice of vinorelbine (30 mg/m2 on days 1 and 8), docetaxel (75 mg/m2 on day 1), gemcitabine (1200 mg/m2 on days 1 and 8), or pemetrexed (500 mg/m2 on day 1). Patients in the bevacizumab group received bevacizumab 15 mg/kg intravenously every 21 days starting with cycle 1 of chemotherapy and continuing for 1 year. We randomly allocated patients (1:1) to group A (chemotherapy alone) or group B (chemotherapy plus bevacizumab), centrally, using permuted blocks sizes and stratified by chemotherapy regimen, stage of disease, histology, and sex. No one was masked to treatment assignment, except the Data Safety and Monitoring Committee. The primary endpoint was overall survival, analysed by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT00324805.FindingsBetween June 1, 2007, and Sept 20, 2013, 1501 patients were enrolled and randomly assigned to the two treatment groups: 749 to group A (chemotherapy alone) and 752 to group B (chemotherapy plus bevacizumab). 383 (26%) of 1458 patients (with complete staging information) had stage IB, 636 (44%) had stage II, and 439 (30%) had stage IIIA disease (stage of disease data were missing for 43 patients). Squamous cell histology was reported for 422 (28%) of 1501 patients. All four cisplatin-based chemotherapy regimens were used: 377 (25%) patients received vinorelbine, 343 (23%) received docetaxel, 283 (19%) received gemcitabine, and 497 (33%) received pemetrexed. At a median follow-up of 50·3 months (IQR 32·9-68·0), the estimated median overall survival in group A has not been reached, and in group B was 85·8 months (95% CI 74·9 to not reached); hazard ratio (group B vs group A) 0·99 (95% CI 0·82-1·19; p=0·90). Grade 3-5 toxicities of note (all attributions) that were reported more frequently in group B (the bevacizumab group) than in group A (chemotherapy alone) were overall worst grade (ie, all grade 3-5 toxicities; 496 [67%] of 738 in group A vs 610 [83%] of 735 in group B), hypertension (60 [8%] vs 219 [30%]), and neutropenia (241 [33%] vs 275 [37%]). The number of deaths on treatment did not differ between the groups (15 deaths in group A vs 19 in group B). Of these deaths, three in group A and ten in group B were considered at least possibly related to treatment.InterpretationAddition of bevacizumab to adjuvant chemotherapy did not improve overall survival for patients with surgically resected early-stage NSCLC. Bevacizumab does not have a role in this setting and should not be considered as an adjuvant therapy for patients with resected early-stage NSCLC.FundingNational Cancer Institute of the National Institutes of Health