By varying excitation energy from ultraviolet to infrared, Raman spectra obtained from both cokes and pyrocarbons revealed the evolution of each band. While the spectra of different samples can be ...very similar at given wavelength, the wavelength dependence should be considered for correlating spectral features to crystallite size La. The D′ band was found to vanish in the UV range. The D band was fitted with one or two Lorentzians for crystallite sizes larger than ∼5nm or below respectively, both centered on the same wavenumber. Both the D band intensity and integrated intensity were accurately obtained, and used to question the range of use of the Tuinstra–Koenig law. The G band shape is well fitted and its width increases monotonously with 2<La<10nm. The energy dependence of ID/IG was found to vary with the excitation energy EL as EL-b with 1<b<4 depending on both La and the sample type. We question the validity of the empirical laws from the literature for having been obtained on a limited sampling and wrongly considered to remain valid over the full ranges of both La and wavelengths. Considering the G band width instead is emphasized.
This observational study was designed to evaluate the reliability and precision of a new digital photoplethysmographic device (Nexfin, BMEYE B.V., Amsterdam, The Netherlands) for continuous and ...non-invasive assessment of arterial pressure and cardiac output.
Fifty consecutive adult subjects were prospectively enrolled at admission to the intensive care unit after conventional cardiac surgery and investigated hourly from T0 to T4. Simultaneous comparative systolic, diastolic, and mean arterial pressures and cardiac index (CI) data points were collected from an invasive radial artery catheter, transpulmonary thermodilution catheter, and the Nexfin device. Correlations were determined by linear regression. The Bland–Altman analysis was used to compare bias, precision, and limits of agreement.
Six (12%) subjects were excluded from the analysis because of the inability to obtain a reliable photoplethysmographic signal. No complications were observed. A significant relationship was found between absolute values of photoplethysmographic and radial systolic (r2=0.56, P<0.001), diastolic (r2=0.61, P<0.001), and mean (r2=0.77, P<0.001) arterial pressures. A significant relationship was also found between transpulmonary thermodilution and Nexfin CI absolute values (r2=0.33, P<0.001). Bias, precision, and limits of agreement between the mean photoplethysmographic and radial arterial pressures were 4.6 (95% confidence interval: 3.7–5.5), 6.5, and −17.3 to 8.1 mm Hg, respectively. The percentage error between transpulmonary thermodilution and the Nexfin for CI measurement was 50%.
The Nexfin device is safe, convenient, and reliable in measuring continuous non-invasive arterial pressure but not interchangeable with transpulmonary thermodilution to monitor CI.
Background
The Nexfin device uses non‐invasive photoplethysmography to monitor cardiac output and respiratory variations in pulse pressure and stroke volume. The aim of this study was to compare ...rapid changes in cardiac index after fluid challenge between Nexfin and bolus transpulmonary thermodilution and the ability to predict fluid responsiveness of dynamic indices given by Nexfin.
Methods
Simultaneous comparative cardiac index were collected from transpulmonary thermodilution and Nexfin before and after fluid challenge in 45 patients following conventional cardiac surgery. Correlations, Bland–Altman analyses and percentage errors were calculated. Pulse pressure variations and stroke volume variations before fluid challenge were collected to assess their discrimination in predicting fluid responsiveness.
Results
Eight (18%) patients were excluded. A weak positive relationship was found between rapid changes in cardiac index after fluid challenge given by both technologies (n = 37, r = 0.39, P = 0.019). Bias, precision and limits of agreements were 0.20 l/min/m2 (95% confidence interval (CI) 0.02–0.40), 0.57 l/min/m2 and ± 1.12 l/min/m2 before fluid challenge, and 0.01 l/min/m2 (95% CI −0.24 to 0.26), 0.74 l/min/m2 and ± 1.45 l/min/m2 after fluid challenge. Percentage errors between Nexfin and transpulmonary thermodilution were 55% and 58% before and after fluid challenge, respectively. Pulse pressure variations and stroke volume variations given by Nexfin were not discriminant to predict fluid responsiveness: areas under receiver operating characteristics curves 0.57 (95% CI 0.40–0.73) and 0.50 (0.33–0.67), respectively.
Conclusions
The Nexfin cannot be used to measure rapid changes in cardiac index following fluid challenge and to predict fluid responsiveness after cardiac surgery.
A 67-year-old man with a history of right upper lobectomy was admitted to our intensive care unit and started on mechanical ventilation because of bilateral pneumonia. Despite appropriate antibiotic ...therapy, the patient’s respiratory status rapidly worsened with increased oxygen requirements and the development of a marked respiratory acidosis.
3D carbon-fibre reinforced carbon composites (3D Cf/C) are used as thermal protection systems for atmospheric re-entry, where they are exposed to strong ablation. Particularly, sublimation of the ...carbonaceous material plays an important role during the re entry. To study this, an arc image furnace under controlled Argon flow is used, with heat fluxes of 8 MWm−2 to 10 MWm−2. The furnace and the sample thermal response have been numerically simulated prior to the experiments and match in-situ temperature measurements. Scanning electron microscopy and 3D profilometry with digital optical microscopy were used in order to characterise the epi-macro-structural and the epi-micro-structural roughness of the composite surface, evidencing a faster recession of the fibres as compared to the matrix. Carbon nanotextures have been assessed by using High-Resolution Transmission Electron Microscopy and Polarised Light Optical Microscopy, showing that the matrix is more organised than the fibre. This can explain the “inverse” behaviour under sublimation as compared to oxidation. The results have been qualitatively interpreted using numerical simulation of differential surface recession.
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•3D Cf/C composites were submitted to fluxes of 8-10 MWm−2 in 1-10 kPa Ar in an image furnace.•The surfaces were investigated by SEM and show a very specific roughness morphology.•The fibre recedes faster than the matrix, as opposed to oxidation tests.•Diffusion of sublimation products is not a limiting phenomenon.•Modeling confirms experimental findings.•The degree of organization of the carbon-based constituents has a positive impact on the recession rate.
To perform a systematic review of the literature on the accuracy of prediction models in the preoperative assessment of adnexal masses.
Studies were identified through the MEDLINE and EMBASE ...databases from inception to March 2008. The MEDLINE search was performed using the keywords "ovarian neoplasms"MeSH NOT "therapeutics"MeSH AND "model" and "ovarian neoplasms"MeSH NOT "therapeutics"MeSH AND "prediction". The Embase search was performed using the keywords ovary tumor AND prediction, ovary tumor AND Mathematical model, and ovary tumor AND statistical model.
The search detected 1,161 publications; from the cross-references, another 116 studies were identified. Language restrictions were not applied. Eligible studies contained data on the accuracy of models predicting the risk of malignancy in ovarian masses. Models were required to combine at least two parameters.
Two independent reviewers selected studies and extracted study characteristics, study quality, and test accuracy. There were 109 accuracy studies that met the selection criteria. Accuracy data were used to form two-by-two contingency tables of the results of the risk score compared with definitive histology. We used bivariate meta-analysis to estimate pooled sensitivities and specificities and to fit summary receiver operating characteristic curves.Studies included in our analysis reported on 83 different prediction models. The model developed by Sassone was the most evaluated prediction model. All models has acceptable sensitivity and specificity. However, the Risk of Malignancy Index I and the Risk of Malignancy Index II, which use the product of the serum CA 125 level, an ultrasound scan result, and the menopausal state, were the best predictors. When 200 was used as the cutoff level, the pooled estimate for sensitivity was 78% for a specificity of 87%.
Based on our review, the Risk of Malignancy Index should be the prediction model of choice in the preoperative assessment of the adnexal mass.
During preoxygenation, the lack of tight fit between the mask and the patient's face results in inward air leak preventing effective preoxygenation. We hypothesized that non-invasive ...positive-pressure ventilation and positive end-expiratory pressure (PEEP) could counteract inward air leak.
Healthy volunteers were randomly assigned to preoxygenated through spontaneous breathing without leak (SB), spontaneous breathing with a calibrated air leak (T-shaped piece between the mouth and the breathing system; SB-leak), or non-invasive positive inspiratory pressure ventilation (inspiratory support +6 cm H2O; PEEP +5 cm H2O) with calibrated leak (PPV-leak). The volunteers breathed through a mouthpiece connected to an anaesthesia ventilator. The expired oxygen fraction (FeO2) and air-leak flow (ml s−1) were measured. The primary end point was the proportion of volunteers with FeO2 >90% at 3 min. The secondary end points were FeO2 at 3 min, time to reach FeO2 of 90%, and the inspiratory air-leak flow.
Twenty healthy volunteers were included. The proportion of volunteers with FeO2 >90% at 3 min was 0% in the SB-leak group, 95% in the SB group, and 100% in the PPV-leak group (P<0.001). At 3 min, the mean standard deviation (sd) FeO2 was 89 (1)%, 76 (1)%, and 90 (0)% in the SB, SB-leak, and PPV-leak groups, respectively (P<0.001). The mean (sd) inward air leak was 59 (12) ml s−1 in the SB-leak group, but 0 (0) ml s−1 in the PPV-leak group (P<0.001).
Preoxygenation through non-invasive positive-pressure ventilation and PEEP provided effective preoxygenation despite an inward air leak.
NCT03087825.
To assess the safety and efficacy of ipilimumab plus nivolumab around selective internal radiation therapy (SIRT) in patients with metastatic uveal melanoma (mUM). We present a retrospective, single ...center study of 32 patients with mUM divided into two groups based on the treatment received between April 2013 and April 2021. The SIRT_IpiNivo cohort was treated with Yttrium-90 microspheres and ipilimumab plus nivolumab before or after the SIRT (
18). The SIRT cohort underwent SIRT but did not receive combined immunotherapy with ipilimumab plus nivolumab (
14). Twelve patients (66.7%) of the SIRT_IpiNivo arm received SIRT as first-line treatment and six patients (33.3%) received ipilimumab plus nivolumab prior to SIRT. In the SIRT group, seven patients (50.0%) received single-agent immunotherapy. One patient treated with combined immunotherapy 68 months after the SIRT was included in this group. At the start of ipilimumab plus nivolumab, 94.4% (
17) presented hepatic metastases and 72.2% (
13) had extra liver disease. Eight patients (44.4%) of the SIRT_IpiNivo group experienced grade 3 or 4 immune related adverse events, mainly colitis and hepatitis. Median overall survival from the diagnosis of metastases was 49.6 months (95% confidence interval (CI); 24.1-not available (NA)) in the SIRT_IpiNivo group compared with 13.6 months (95% CI; 11.5-NA) in the SIRT group (log-rank
-value 0.027). The presence of extra liver metastases at the time of SIRT, largest liver lesion more than 8 cm (M1c) and liver tumor volume negatively impacted the survival. This real-world cohort suggests that a sequential treatment of ipilimumab plus nivolumab and SIRT is a well-tolerated therapeutic approach with promising survival rates.
Bacterial resistance to antibiotics is a daily concern in intensive care units. However, few data are available concerning the clinical consequences of in-vitro-defined resistance.
To compare the ...mortality of patients with nosocomial infections according to bacterial resistance profiles.
The prospective surveillance registry in 29 French intensive care units (ICUs) participating during the years 2000–2013 was retrospectively analysed. All patients presenting with a nosocomial infection in ICU were included.
The registry contained 88,000 eligible patients, including 10,001 patients with a nosocomial infection. Among them, 3092 (36.7%) were related to resistant micro-organisms. Gram-negative bacilli exhibited the highest rate of resistance compared to Gram-positive cocci (52.8% vs 48.1%; P < 0.001). In-hospital mortality was higher in cases of patients with antibiotic-resistant infectious agents (51.9% vs 45.5%; P < 0.001), and critical care length of stay was longer (33 ± 26 vs 29 ± 22 days; P < 0.001). These results remained significant after SAPS II matching (P < 0.001) and in the Gram-negative bacilli and Gram-positive cocci subgroups. No difference in mortality was found with respect to origin prior to admission.
Patients with bacterial resistance had higher ICU mortality and increased length of stay, regardless of the bacterial species or origin of the patient.
Summary
Peri‐operative lidocaine infusion warrants investigation in bariatric surgery because obese patients present different physiological and pharmacological risks. This single‐centre, ...prospective, randomised double‐blind placebo‐controlled study enrolled obese patients scheduled for laparoscopic bariatric surgery using an enhanced recovery protocol. Patients received either lidocaine (bolus of 1.5 mg.kg−1, then a continuous infusion of 2 mg.kg−1.h−1 until the end of the surgery, then 1 mg.kg−1.h−1 for 1 h in the recovery area) or identical volumes and rates of 0.9% saline. The primary outcome was the consumption of the equivalent of oxycodone consumption over the first 3 postoperative days. Secondary outcomes were: postoperative pain; incidence of nausea and vomiting; bowel function recovery; and lengths of stay in the recovery area and in hospital. Plasma concentrations of lidocaine were measured. On the 178 patients recruited, data were analysed from 176. The median (IQR range) equivalent intravenous oxycodone consumption was 3.3 mg (0.0–6.0 0.0–14.5) and 5.0 mg (3.3–7.0 3.3–20.0) in the lidocaine and saline groups, respectively (difference between medians (95%CI): 1.7 (0.6–3.4) mg; p = 0.004). Length of stay in the recovery area, postoperative pain, nausea and vomiting, day of recovery of bowel function, and length of stay in hospital were not different between groups. Mean (SD) lidocaine plasma concentrations were 2.44 (0.70) µg.ml−1 and 1.77 (0.51) µg.ml−1 at the end of surgery and 1 hour after the end of infusion, respectively. Lidocaine infusion during bariatric surgery resulted in a clinically non‐relevant difference in postoperative oxycodone consumption.
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