Summary
The newly introduced Nexfin® device allows analysis of the blood pressure trace produced by a non‐invasive finger cuff. We compared the cardiac output derived from the Nexfin and PiCCO, using ...transcardiopulmonary thermodilution, during cardiac surgery. Forty patients with preserved left ventricular function undergoing elective coronary artery bypass graft surgery were studied after induction of general anaesthesia and until discharge to the intensive care unit. There was a significant correlation between Nexfin and PiCCO before (r2 = 0.81, p < 0.001) and after (r2 = 0.56, p < 0.001) cardiopulmonary bypass. Bland–Altman analysis demonstrated the mean bias of Nexfin to be −0.1 (95% limits of agreement −0.6 to +0.5, percentage error 23%) and −0.1 (−0.8 to +0.6, 26%) l.min−1.m−2, before and after cardiopulmonary bypass, respectively. After a passive leg‐raise was performed, there was also good correlation between the two methods, both before (r2 = 0.72, p < 0.001) and after (r2 = 0.76, p < 0.001) cardiopulmonary bypass. We conclude that the Nexfin is a reliable method of measuring cardiac output during and after cardiac surgery.
Abstract
Monolayer transition metal dichalcogenides (TMD) have numerous potential applications in ultrathin electronics and photonics. The exposure of TMD-based devices to light generates ...photo-carriers resulting in an enhanced conductivity, which can be effectively used, e.g., in photodetectors. If the photo-enhanced conductivity persists after removal of the irradiation, the effect is known as persistent photoconductivity (PPC). Here we show that ultraviolet light (λ = 365 nm) exposure induces an extremely long-living giant PPC (GPPC) in monolayer MoS
2
(ML-MoS
2
) field-effect transistors (FET) with a time constant of ~30 days. Furthermore, this effect leads to a large enhancement of the conductivity up to a factor of 10
7
. In contrast to previous studies in which the origin of the PPC was attributed to extrinsic reasons such as trapped charges in the substrate or adsorbates, we show that the GPPC arises mainly from the intrinsic properties of ML-MoS
2
such as lattice defects that induce a large number of localized states in the forbidden gap. This finding is supported by a detailed experimental and theoretical study of the electric transport in TMD based FETs as well as by characterization of ML-MoS
2
with scanning tunneling spectroscopy, high-resolution transmission electron microscopy, and photoluminescence measurements. The obtained results provide a basis for the defect-based engineering of the electronic and optical properties of TMDs for device applications.
Reported outcome benefits after surgical pleth index (SPI, GE Healthcare, Helsinki, Finland) guided anaesthesia are conflicting. One potential explanation may be the lack of evidence for the ...selection of meaningful SPI target values. A recently published trial found an SPI cut-off of 30 as a ‘best-fit’ to predict moderate-to-severe acute postoperative pain. This prospective trial was designed to validate this target and to investigate the influence of patient age on SPI in this context.
After ethics approval, 200 patients undergoing non-emergency surgery were enrolled. Data related to SPI, heart rate (HR), and mean arterial pressure (MAP) were recorded for the last 5 min of surgery, just before arousal. After admission to recovery, pain scores (numeric rating scale NRS, 0–10) were obtained every 5 min for 15 min.
The data of 196 patients were analysed. Receiver-operating curve analysis showed a cut-off SPI value of 29 to be the optimum intraoperative target to discriminate between NRS 0–3 and 4–10. This confirms the ‘best fit’ cut-off for SPI published previously. Though still superior to HR and MAP, the sensitivity and specificity of the SPI were only poor. Age had no influence on the predictive accuracy of SPI.
An SPI of approximately 30 was confirmed as having the best sensitivity/specificity to predict moderate-to-severe pain in the postanaesthesia care unit. However, the predictive accuracy was overall poor and not influenced by patient age.
ACTRN12617001475336.
Measurement of the balance between nociception and anti-nociception during anaesthesia is challenging and not yet clinically established. The Surgical pleth index (SPI), derived from ...photoplethysmography, was proposed as a surrogate measure of nociception. Recently, the analgesia nociception index (ANI) derived by heart rate (HR) variability was developed. The aim of the present study was to challenge the ability of ANI compared with SPI to detect standardized noxious stimulation during propofol–remifentanil anaesthesia.
After Ethics approval and informed consent, 25 patients were anaesthetized with propofol bispectral index (BIS) 30–60. A laryngeal mask (LMA) was inserted and remifentanil stepwise increased to effect-site concentrations (Ceremi) of 0, 2, and 4 ng ml−1. At each step, tetanic stimulation (STIM) was applied. ANI, SPI, BIS, HR, and mean arterial pressure (MAP) were obtained before and after LMA insertion and each STIM. Analysis was performed using Wilcoxon rank tests and calculation of prediction probabilities (PK).
ANI and SPI, but not BIS, HR, or MAP, were significantly (P<0.05) changed at all examined steps. ANI response to STIM was (median IQR) −24 −12–35, −30 −20–−40 and −13 −5–−27 at 0, 2 and 4 ng ml−1 Ceremi. However, prediction of movement to STIM was not better than by chance, as PK values were 0.41 (0.08) for ANI and 0.62 (0.08) for SPI.
The two variables, ANI and SPI, enabled consistent reflection of stimulation during propofol–remifentanil anaesthesia. Nevertheless, ANI and SPI may improve detection but not prediction of a possible inadequate nociception–anti-nociception balance.
Clinicaltrials.gov Identifier. NCT01522508.
Recognising neuropsychiatric involvement by systemic lupus erythematosus (SLE) is of growing importance, however many barriers to this exist at multiple levels of our currently available diagnostic ...algorithms that may ultimately delay its diagnosis and subsequent treatment. The heterogeneous and non-specific clinical syndromes, serological and cerebrospinal fluid (CSF) markers and neuroimaging findings that often do not mirror disease activity, highlight important research gaps in the diagnosis of neuropsychiatric SLE (NPSLE). Formal neuropsychological assessments or the more accessible screening metrics may also help improve objective recognition of cognitive or mood disorders. Novel serum and CSF markers, including autoantibodies, cytokines and chemokines have also shown increasing utility as part of diagnosis and monitoring, as well as in distinguishing NPSLE from SLE patients without SLE-related neuropsychiatric manifestations. Novel neuroimaging studies also expand upon our existing strategy by quantifying parameters that indicate microarchitectural integrity or provide an assessment of neuronal function. Some of these novel markers have shown associations with specific neuropsychiatric syndromes, suggesting that future research move away from considering NPSLE as a single entity but rather into its individually recognized neuropsychiatric manifestations. Nevertheless, it is likely that a composite panel of these investigations will be needed to better address the gaps impeding recognition of neuropsychiatric involvement by SLE.
Evaluation of analgesia and antinociception during anaesthesia is still a challenging issue and routinely based on indirect and non-specific signs such as movement, tachycardia, or lacrimation. ...Recently, the surgical pleth index (SPI) derived by finger plethysmography was introduced to detect nociceptive stimulation during anaesthesia. While SPI guidance reduced the number of unwanted events during total i.v. anaesthesia (TIVA), the impact of SPI during volatile-based anaesthesia with intermittent opioid administration has not yet been elucidated.
Ninety-four patients were randomized into either SPI-guided analgesia or standard practice (Control). In both groups, anaesthesia was maintained with sevoflurane to keep bispectral index values between 40 and 60. In the SPI group, patients received a sufentanil bolus (10 μg) whenever SPI value increased above 50, whereas in the control group, sufentanil was administered according to standard clinical practice. The number of unwanted somatic events, haemodynamics, sufentanil consumption, and recovery times were recorded.
The incidence of intraoperative unwanted somatic events was comparable between the groups (P=0.89). No significant differences with respect to hypotensive or hypertensive events were found. The mean (95% confidence interval) sufentanil consumption was non-significantly (P=0.07) reduced in the SPI group, 0.64 (0.57–0.71) vs 0.78 (0.64–0.91) µg min−1. Recovery times were comparable between the groups.
Sufentanil administration guided by SPI during sevoflurane anaesthesia is clinically feasible. In contrast to TIVA, it did not improve anaesthesia conduct with respect to unwanted somatic events, haemodynamic stability, sufentanil consumption, emergence time, or post-anaesthesia care unit care. Therefore, we conclude that anaesthesia regimen has an impact on beneficial effects by SPI guidance.
NCT01525537. (Registered at Clinicaltrials.gov.)
Background: Respiratory variations in plethysmographic waveform amplitudes derived from pulse oximetry are believed to predict fluid responsiveness. The non‐invasive pleth variability index (PVI) is ...a variable based on the calculation of changes in the perfusion index (PI). The aim of the following study was to examine whether the predictive power of PVI depends on different values of PI.
Methods: Eighty‐one patients undergoing elective coronary artery surgery were studied before operation: at baseline after induction of anaesthesia and during passive leg raising (PLR). Each patient was monitored with central venous pressure (CVP), the PiCCO monitor and the non‐invasive Masimo monitoring system. Stroke volume index by transpulmonary thermodilution (SVITPTD), pulse pressure variation (PPV), stroke volume variation (SVV) and systemic vascular resistance index (SVRI) were measured using the PiCCO monitoring system. PI and PVI were obtained by pulse oximetry.
Results: Responders were defined to increase their SVITPTD>15% after PLR. The highest area under the curve (AUC) was found for PPV (AUC: 0.83, P<0.0001) and SVV (AUC: 0.72, P=0.002), in contrast to PVI (AUC: 0.60, P=0.11) and CVP (AUC: 0.60, P=0.13). The accuracy of PVI to predict fluid responsiveness was improved on analysing patients with higher PI values. PI of about 4% (n=45) achieved statistical significance (AUC: 0.72, P=0.01).
Conclusion: The PVI was not able to predict fluid responsiveness with sufficient accuracy. In patients with higher perfusion states, the PVI improved its ability to predict haemodynamic changes, strongly suggesting a relevant influence of the PI on the PVI.
Summary
This prospective study assessed whether respiratory variations in velocity time integral, peak blood flow velocity and non‐invasive pleth variability index are useful measurements in infants ...undergoing congenital heart surgery and determined threshold values that may help guide fluid administration. In 27 infants receiving mechanical ventilation, of mean (SD) weight 10.4 (6.3) kg, 13 increased their stroke volume index ≥ 15% following a fluid challenge and 14 did not. The best area under the receiver operating characteristic curve was for the echocardiographic‐derived variables respiratory variation in blood peak flow velocity (area under the ROC curve = 0.92; p = 0.0002) and respiratory variation of the velocity time integral (area under the ROC curve = 0.84; p = 0.002). The pleth variability index also predicted fluid responsiveness (area under the ROC curve = 0.79; p = 0.01), in contrast to heart rate (area under the ROC curve = 0.53; p = 0.75) and central venous pressure (area under the ROC curve = 0.57; p = 0.52).
Several unidentified infrared emission bands (UIBs) have been assigned to neutral C60 molecules present in circumstellar and interstellar environments. However, due to the similarity of the infrared ...(IR) spectra of C60 in the solid state and in the gas phase, as of yet there is no consensus on the aggregation state of C60. In this article, we show that even strong covalent chemical bonding might have very little influence on the IR spectrum of C60, and that therefore such chemically bonded C60 could be the carrier of the same UIBs. It would best explain observations like the missing emission from C60 ions and a large variation of relative band intensities between different sources. We demonstrate that such a chemically bonded C60 can be produced by the co-condensation of C atoms together with C60 molecules, which leads to the formation of a three-dimensional C60 polymer film. Such polymerized C60 molecules cannot easily desorb, while their spectral properties in the visible and IR spectral ranges are almost undisturbed by polymerization.
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