Project description:(1) Background: Malperfusion is a central limiting factor in the setting of acute Type A aortic dissections (AAAD). We sought to find preoperative metabolic acidosis thresholds that might influence decision-making in this setting. (2) Methods: We retrospectively reviewed consecutive patients operated on with AAAD between January 2002 and December 2017. We analyzed preoperative variables that might influence early and long-term outcomes, with particular emphasis on malperfusion markers. (3) Results: Our sample consisted of 153 patients, most of them male (69.2%), with a mean age of 55.89 ± 12.8 years. Malperfusion was present in 20.9% of cases: peripheric 25, renal 7, cerebral 4, and mesenteric 3. Cardiogenic shock was present in 18.9% of patients. Logistic regression revealed entry site (odds ratio (OR) = 2.83, p = 0.03), cardiogenic shock (OR = 3.30, p = 0.03), prebypass pH (OR = 0.93, p = 0.02) as independent risk factors for early death (<30 days). Receiver operating characteristic (ROC) analysis identified a prebypass pH of 7.25 as a cutpoint for an unfavourable early outcome. Patients whose prebypass pH was ≤7.25 had a 2.98 higher relative risk (65.7% vs. 22%, p < 0.001). Prebypass pH 7.25 (hazard ratio (HR) = 4.00, p < 0.01) and entry site (HR = 2.10, p = 0.04) were independent predictors of early phase survival (<30 days), while long-term survival (>30 days) was determined by age >65 years (HR = 3.12, p = 0.02). (4) Conclusions: Patients with a prebypass pH ≤ 7.25 have an unacceptably high early mortality after AAAD repair. Those patients might benefit from a two-stage approach.
Project description:During the COVID-19 pandemic, a shortage of mechanical ventilators was reported and ventilator sharing between patients was proposed as an ultimate solution. Two lung simulators were ventilated by one anesthesia machine connected through two respiratory circuits and T-pieces. Five different combinations of compliances (30-50 mL × cmH2O-1) and resistances (5-20 cmH2O × L-1 × s-1) were tested. The ventilation setting was: pressure-controlled ventilation, positive end-expiratory pressure 15 cmH2O, inspiratory pressure 10 cmH2O, respiratory rate 20 bpm. Pressures and flows from all the circuit sections have been recorded and analyzed. Simulated patients with equal compliance and resistance received similar ventilation. Compliance reduction from 50 to 30 mL × cmH2O-1 decreased the tidal volume (VT) by 32% (418 ± 49 vs. 285 ± 17 mL). The resistance increase from 5 to 20 cmH2O × L-1 × s-1 decreased VT by 22% (425 ± 69 vs. 331 ± 51 mL). The maximal alveolar pressure was lower at higher compliance and resistance values and decreased linearly with the time constant (r² = 0.80, p < 0.001). The minimum alveolar pressure ranged from 15.5 ± 0.04 to 16.57 ± 0.04 cmH2O. Cross-flows between the simulated patients have been recorded in all the tested combinations, during both the inspiratory and expiratory phases. The simultaneous ventilation of two patients with one ventilator may be unable to match individual patient's needs and has a high risk of cross-interference.
Project description:This paper explores the processing of sentences with a much less coordinator (I don't own a pink hat, much less a red one). This understudied ellipsis sentence, one of several focus-sensitive coordination structures, imposes syntactic and semantic conditions on the relationship between the correlate (a pink hat) and remnant (a red one). We present the case of zero-adjective contrast, in which an NP remnant introduces an adjective without an overt counterpart in the correlate (I don't own a hat, much less a red one). Although zero-adjective contrast could in principle ease comprehension by limiting the possible relationships between the remnant and correlate to entailment, we find that zero-adjective contrast is avoided in production and taxing in online processing. Results from several studies support a processing model in which syntactic parallelism is the primary guide for determining contrast in ellipsis structures, even when violating parallelism would assist in computing semantic relationships.
Project description:Shortages of Bacille Calmette‐Guérin (BCG) have implications for the management of patients with non‐muscle‐invasive bladder cancers. Further complications come as a result of COVID‐19 for which BCG also shows some promising prospects.
Project description:ObjectivesThere is limited evidence on the impact of protocolized ventilator weaning in pediatric acute respiratory distress syndrome, despite utilization in clinical trials and clinical care. We aimed to determine whether protocolized ventilator weaning shortens mechanical ventilation duration and PICU length of stay in pediatric acute respiratory distress syndrome survivors.DesignSecondary analysis of a prospective pediatric acute respiratory distress syndrome (Berlin definition) cohort from July 2011 to June 2019 analyzed using interrupted time series analysis pre- and postimplementations of a ventilator-weaning pathway. We compared duration of invasive ventilation and PICU length of stay in survivors before and after implementation of a ventilator-weaning pathway. We excluded PICU nonsurvivors and subjects with greater than 100 ventilator days.SettingLarge academic tertiary-care PICU.PatientsChildren with acute respiratory distress syndrome who survived to PICU discharge with less than or equal to 100 days of invasive mechanical ventilation.InterventionsImplementation of a ventilator-weaning pathway on May 2016.Measurements and main resultsOf 723 children with acute respiratory distress syndrome, 132 subjects died and six subjects with ventilation greater than 100 days were excluded. Of the remaining 585 subjects, 375 subjects had acute respiratory distress syndrome prior to pathway intervention and 210 after. Patients in the preintervention epoch were younger, more likely to have infectious acute respiratory distress syndrome, and had increased use of alternative ventilator modes. Pathway adoption was rapid and sustained. Controlling for temporality, pathway implementation was associated with a decrease of a median 3.6 ventilator days (95% CI, -5.4 to -1.7; p < 0.001). There was no change in the reintubation rates. Results were robust to multiple sensitivity analyses adjusting for confounders.ConclusionsVentilator-weaning pathway implementation shortened invasive ventilation duration in pediatric acute respiratory distress syndrome survivors with no change in reintubation. The effect size of this intervention was comparable with those targeted in acute respiratory distress syndrome trials.
Project description:Ferumoxytol ultrasmall superparamagnetic iron oxide nanoparticles can enhance contrast between neuroinflamed and normal-appearing brain tissue when used as a contrast agent for high-sensitivity magnetic resonance imaging (MRI). Here we used an anti-dextran antibody (Dx1) that binds the nanoparticle's carboxymethyldextran coating to differentiate ferumoxytol from endogenous iron and localize it unequivocally in brain tissue. Intravenous injection of ferumoxytol into immune-competent rats that harbored human tumor xenograft-induced inflammatory brain lesions resulted in heterogeneous and lesion-specific signal enhancement on MRI scans in vivo. We used Dx1 immunolocalization and electron microscopy to identify ferumoxytol in affected tissue post-MRI. We found that ferumoxytol nanoparticles were taken up by astrocyte endfeet surrounding cerebral vessels, astrocyte processes, and CD163(+)/CD68(+) macrophages, but not by tumor cells. These results provide a biological basis for the delayed imaging changes seen with ferumoxytol and indicate that ferumoxytol-MRI can be used to assess the inflammatory component of brain lesions in the clinic.
Project description:IntroductionWe previously showed in animals that the ratio of inspired tidal volume (Vtinsp) to inspiratory peak electrical activity of the diaphragm (EAdipk) can be used to quantify the respective patient and ventilator breath contributions (PVBCs) during neurally adjusted ventilatory assist (NAVA). The PVBC index has not been tested clinically.MethodsWe studied 12 intubated and mechanically ventilated patients with acute respiratory failure and measured EAdipk, airway (Paw) and inspiratory esophageal pressure (Pes) and Vtinsp. We applied 11 different NAVA levels, increasing them every 3 minutes in steps of 0.3 cm H₂O/μV from 0 to 3.0 cmH₂O/μV. At each NAVA level, one breath was non-assisted (NAVA level 0). PVBC indices were calculated by relating Vtinsp/EAdipk of the non-assisted breath to Vtinsp/EAdipk of the assisted breath(s) using one ((N1)PVBC) or the mean value of five preceding assisted breaths ((X5)PVBC). During assisted breaths, inspiratory changes in Pes (∆Pes) and transpulmonary (ΔPtp) pressures were used to calculate the relative contribution of patient to total inspiratory lung-distending pressures (ΔPes/ΔPtp). Matching of respiratory drive indices and squaring of the PVBC was evaluated for their effect on the correlation between PVBC and ΔPes/ΔPtp. Linear regression analysis and Bland-Altman analysis were applied to compare indices.ResultsUsing an average of five assisted breaths prior to the non-assisted breath and squaring the PVBC ((X5)PVBC(2)) improved determination coefficients (P <0.05), adjusted the regression slope and intercept between PVBC and ΔPes/ΔPtp toward identity (P <0.05) and reduced bias (P <0.05). Matching EAdipk between non-assisted and assisted breaths within the range of 0.77 to 1.30 improved the relationship between (X5)PVBC(2) and ΔPes/ΔPtp (P <0.05) and abolished the need for EAdi normalization in the PVBC calculation (R(2) = 0.96; bias = 0.16 ± 0.06; precision = 0.33 ± 0.08 (mean and 95% confidence interval)).ConclusionsThis clinical study confirms previous experimental results showing that the PVBC(2) predicts the contribution of the inspiratory muscles versus that of the ventilator during NAVA, when differences in effort (EAdi) between non-assisted and assisted breaths are limited. PVBC could help to quantify and standardize the adjustment of the level of assist, and hence reduce the risks of excessive ventilatory assist in patients.Trial registrationClinicalTrials.gov NCT01663480. Registered 9 August 2012.