Limiting Overdistention or Collapse When Mechanically Ventilating Injured Lungs: A Randomized Study in a Porcine Model.

Rationale: It is unknown whether preventing overdistention or collapse is more important when titrating positive end-expiratory pressure (PEEP) in acute respiratory distress syndrome (ARDS). Objectives: To compare PEEP targeting minimal overdistention or minimal collapse or using a compromise between collapse and overdistention in a randomized trial and to assess the impact on respiratory mechanics, gas exchange, inflammation, and hemodynamics. Methods: In a porcine model of ARDS, lung collapse and overdistention were estimated using electrical impedance tomography during a decremental PEEP titration. Pigs were randomized to three groups and ventilated for 12 hours: PEEP set at ⩽3% of overdistention (low overdistention), ⩽3% of collapse (low collapse), and the crossing point of collapse and overdistention. Measurements and Main Results: Thirty-six pigs (12 per group) were included. Median (interquartile range) values of PEEP were 7 (6-8), 11 (10-11), and 15 (12-16) cm H2O in the three groups (P < 0.001). With low overdistension, 6 (50%) pigs died, whereas survival was 100% in both other groups. Cause of death was hemodynamic in nature, with high transpulmonary vascular gradient and high epinephrine requirements. Compared with the other groups, pigs surviving with low overdistension had worse respiratory mechanics and gas exchange during the entire protocol. Minimal differences existed between crossing-point and low-collapse animals in physiological parameters, but postmortem alveolar density was more homogeneous in the crossing-point group. Inflammatory markers were not significantly different. Conclusions: PEEP to minimize overdistention resulted in high mortality in an animal model of ARDS. Minimizing collapse or choosing a compromise between collapse and overdistention may result in less lung injury, with potential benefits of the compromise approach.

Expiratory Muscle Activity Counteracts Positive End-Expiratory Pressure and Is Associated with Fentanyl Dose in Patients with Acute Respiratory Distress Syndrome.

Rationale: Hypoxemia during mechanical ventilation might be worsened by expiratory muscle activity, which reduces end-expiratory lung volume through lung collapse. A proposed mechanism of benefit of neuromuscular blockade in acute respiratory distress syndrome (ARDS) is the abolition of expiratory efforts. This may contribute to the restoration of lung volumes. The prevalence of this phenomenon, however, is unknown. Objectives: To investigate the incidence and amount of end-expiratory lung impedance (EELI) increase after the administration of neuromuscular blocking agents (NMBAs), clinical factors associated with this phenomenon, its impact on regional lung ventilation, and any association with changes in pleural pressure. Methods: We included mechanically ventilated patients with ARDS monitored with electrical impedance tomography (EIT) who received NMBAs in one of two centers. We measured changes in EELI, a surrogate for end-expiratory lung volume, before and after NMBA administration. In an additional 10 patients, we investigated the characteristic signatures of expiratory muscle activity depicted by EIT and esophageal catheters simultaneously. Clinical factors associated with EELI changes were assessed. Measurements and Main Results: We included 46 patients, half of whom showed an increase in EELI of >10% of the corresponding Vt (46.2%; IQR, 23.9-60.9%). The degree of EELI increase correlated positively with fentanyl dosage and negatively with changes in end-expiratory pleural pressures. This suggests that expiratory muscle activity might exert strong counter-effects against positive end-expiratory pressure that are possibly aggravated by fentanyl. Conclusions: Administration of NMBAs during EIT monitoring revealed activity of expiratory muscles in half of patients with ARDS. The resultant increase in EELI had a dose-response relationship with fentanyl dosage. This suggests a potential side effect of fentanyl during protective ventilation.

Evolution of ancient satellite DNAs in extant alligators and caimans (Crocodylia, Reptilia).

BACKGROUND: Crocodilians are one of the oldest extant vertebrate lineages, exhibiting a combination of evolutionary success and morphological resilience that has persisted throughout the history of life on Earth. This ability to endure over such a long geological time span is of great evolutionary importance. Here, we have utilized the combination of genomic and chromosomal data to identify and compare the full catalogs of satellite DNA families (satDNAs, i.e., the satellitomes) of 5 out of the 8 extant Alligatoridae species. As crocodilian genomes reveal ancestral patterns of evolution, by employing this multispecies data collection, we can investigate and assess how satDNA families evolve over time. RESULTS: Alligators and caimans displayed a small number of satDNA families, ranging from 3 to 13 satDNAs in A. sinensis and C. latirostris, respectively. Together with little variation both within and between species it highlighted long-term conservation of satDNA elements throughout evolution. Furthermore, we traced the origin of the ancestral forms of all satDNAs belonging to the common ancestor of Caimaninae and Alligatorinae. Fluorescence in situ experiments showed distinct hybridization patterns for identical orthologous satDNAs, indicating their dynamic genomic placement. CONCLUSIONS: Alligators and caimans possess one of the smallest satDNA libraries ever reported, comprising only four sets of satDNAs that are shared by all species. Besides, our findings indicated limited intraspecific variation in satellite DNA, suggesting that the majority of new satellite sequences likely evolved from pre-existing ones.

High Mechanical Power and Driving Pressures are Associated With Postoperative Respiratory Failure Independent From Patients' Respiratory System Mechanics.

OBJECTIVES: High mechanical power and driving pressure (ΔP) have been associated with postoperative respiratory failure (PRF) and may be important parameters guiding mechanical ventilation. However, it remains unclear whether high mechanical power and ΔP merely reflect patients with poor respiratory system mechanics at risk of PRF. We investigated the effect of mechanical power and ΔP on PRF in cohorts after exact matching by patients' baseline respiratory system compliance. DESIGN: Hospital registry study. SETTING: Academic hospital in New England. PATIENTS: Adult patients undergoing general anesthesia between 2008 and 2020. INTERVENTION: None. MEASUREMENTS AND MAIN RESULTS: The primary exposure was high (≥ 6.7 J/min, cohort median) versus low mechanical power and the key-secondary exposure was high (≥ 15.0 cm H 2 O) versus low ΔP. The primary endpoint was PRF (reintubation or unplanned noninvasive ventilation within seven days). Among 97,555 included patients, 4,030 (4.1%) developed PRF. In adjusted analyses, high intraoperative mechanical power and ΔP were associated with higher odds of PRF (adjusted odds ratio [aOR] 1.37 [95% CI, 1.25-1.50]; p < 0.001 and aOR 1.45 [95% CI, 1.31-1.60]; p < 0.001, respectively). There was large variability in applied ventilatory parameters, dependent on the anesthesia provider. This facilitated matching of 63,612 (mechanical power cohort) and 53,260 (ΔP cohort) patients, yielding identical baseline standardized respiratory system compliance (standardized difference [SDiff] = 0.00) with distinctly different mechanical power (9.4 [2.4] vs 4.9 [1.3] J/min; SDiff = -2.33) and ΔP (19.3 [4.1] vs 11.9 [2.1] cm H 2 O; SDiff = -2.27). After matching, high mechanical power and ΔP remained associated with higher risk of PRF (aOR 1.30 [95% CI, 1.17-1.45]; p < 0.001 and aOR 1.28 [95% CI, 1.12-1.46]; p < 0.001, respectively). CONCLUSIONS: High mechanical power and ΔP are associated with PRF independent of patient's baseline respiratory system compliance. Our findings support utilization of these parameters for titrating mechanical ventilation in the operating room and ICU.

Influence of Fractional Inspired Oxygen Tension on Lung Perfusion Distribution, Regional Ventilation, and Lung Volume during Mechanical Ventilation of Supine Healthy Swine.

BACKGROUND: Lower fractional inspired oxygen tension (Fio2) during general anesthesia can reduce lung atelectasis. The objectives are to evaluate the effect of two Fio2 (0.4 and 1) during low positive end-expiratory pressure (PEEP) ventilation over lung perfusion distribution, volume, and regional ventilation. These variables were evaluated at two PEEP levels and unilateral lung atelectasis. METHODS: In this exploratory study, 10 healthy female piglets (32.3 ± 3.4 kg) underwent mechanical ventilation in two atelectasis models: (1) bilateral gravitational atelectasis (n = 6), induced by changes in PEEP and Fio2 in three combinations: high PEEP with low Fio2 (Fio2 = 0.4), zero PEEP (PEEP0) with low Fio2 (Fio2 = 0.4), and PEEP0 with high Fio2 (Fio2 = 1); and (2) unilateral atelectasis (n = 6), induced by left bronchial occlusion, with the left lung aerated (Fio2 = 0.21) and low aerated (Fio2 = 1; n = 5 for this step). Measurements were conducted after 10 min in each step, encompassing assessment of respiratory mechanics, oxygenation, and hemodynamics; lung ventilation and perfusion by electrical impedance tomography; and lung aeration and perfusion by computed tomography. RESULTS: During bilateral gravitational atelectasis, PEEP reduction increased atelectasis in dorsal regions, decreased respiratory compliance, and distributed lung ventilation to ventral regions with a parallel shift of perfusion to the same areas. With PEEP0, there were no differences between low and high Fio2 in respiratory compliance (23.9 ± 6.5 ml/cm H2O vs. 21.9 ± 5.0; P = 0.441), regional ventilation, and regional perfusion, despite higher lung collapse (18.6 ± 7.6% vs. 32.7 ± 14.5%; P = 0.045) with high Fio2. During unilateral lung atelectasis, the deaerated lung had a lower shunt (19.3 ± 3.6% vs. 25.3 ± 5.5%; P = 0.045) and lower computed tomography perfusion to the left lung (8.8 ± 1.8% vs. 23.8 ± 7.1%; P = 0.007). CONCLUSIONS: PEEP0 with low Fio2, compared with high Fio2, did not produce significant changes in respiratory system compliance, regional lung ventilation, and perfusion despite significantly lower lung collapse. After left bronchial occlusion, the shrinkage of the parenchyma with Fio2 = 1 enhanced hypoxic pulmonary vasoconstriction, reducing intrapulmonary shunt and perfusion of the nonventilated areas.

Multiple karyotype differences between populations of the Hoplias malabaricus (Teleostei; Characiformes), a species complex in the gray area of the speciation process.

Neotropical fishes exhibit remarkable karyotype diversity, whose evolution is poorly understood. Here, we studied genetic differences in 60 individuals, from 11 localities of one species, the wolf fish Hoplias malabaricus, from populations that include six different "karyomorphs". These differ in Y-X chromosome differentiation, and, in several cases, by fusions with autosomes that have resulted in multiple sex chromosomes. Other differences are also observed in diploid chromosome numbers and morphologies. In an attempt to start understanding how this diversity was generated, we analyzed within- and between-population differences in a genome-wide sequence data set. We detect clear genotype differences between karyomorphs. Even in sympatry, samples with different karyomorphs differ more in sequence than samples from allopatric populations of the same karyomorph, suggesting that they represent populations that are to some degree reproductively isolated. However, sequence divergence between populations with different karyomorphs is remarkably low, suggesting that chromosome rearrangements may have evolved during a brief evolutionary time. We suggest that the karyotypic differences probably evolved in allopatry, in small populations that would have allowed rapid fixation of rearrangements, and that they became sympatric after their differentiation. Further studies are needed to test whether the karyotype differences contribute to reproductive isolation detected between some H. malabaricus karyomorphs.

E6020, a TLR4 Agonist Adjuvant, Enhances Both Antibody Titers and Isotype Switching in Response to Immunization with Hapten-Protein Antigens and Is Diminished in Mice with TLR4 Signaling Insufficiency.

The mechanisms by which TLR4-based adjuvants enhance immunogenicity are not fully understood. We have taken advantage of a novel knock-in mouse strain that homozygously expresses two single-nucleotide polymorphisms (SNPs) that are homologous to human TLR4 (rs4986790 and rs4986791) and have been associated with LPS hyporesponsiveness in vivo and in vitro. TLR4-SNP (coexpressing mutations D298G/N397I in TLR4) mice that recapitulate the human phenotype were compared with wild-type (WT) mice for their hapten-specific Ab responses after immunization with hapten 4-hydroxy-3-nitrophenyl acetyl (NP) NP-Ficoll or NP-OVA in the absence or presence of a water-soluble TLR4 analog adjuvant, E6020. IgM and IgG anti-NP responses were comparable in WT and TLR4-SNP mice after immunization with either NP-Ficoll or NP-OVA only. E6020 significantly yet transiently improved the IgM and IgG anti-NP responses of both WT and TLR4-SNP mice to NP-Ficoll (T-independent), with modestly enhanced Ab production in WT mice. In contrast, T-dependent (NP-OVA), adjuvant-enhanced responses showed sustained elevation of NP-specific Ab titers in WT mice, intermediate responses in TLR4-SNP mice, and negligible enhancement in TLR4-/- mice. E6020-enhanced early humoral responses in WT and TLR4-SNP mice to NP-OVA favored an IgG1 response. After a second immunization, however, the immune responses of TLR4-SNP mice remained IgG1 dominant, whereas WT mice reimmunized with NP-OVA and E6020 exhibited increased anti-NP IgG2c titers and a sustained increase in the IgG1 and IgG2c production by splenocytes. These findings indicate that E6020 increases and sustains Ab titers and promotes isotype class switching, as evidenced by reduced titers and IgG1-dominant immune responses in mice with TLR4 insufficiency.

Acute kidney injury in children undergoing cardiac surgery: predictive value of kidney arterial Doppler-based variables.

BACKGROUND: Acute kidney injury (AKI) is a common condition in critically ill children and is associated with increased morbidity and mortality. This study aimed to assess the performance of point-of-care ultrasonography to predict AKI in children undergoing cardiac surgery. METHODS: In this prospective study, consecutive children underwent kidney Doppler ultrasound examination within 24 h following cardiac surgery, and an experienced operator obtained both renal resistive index (RRI) and renal pulsatility index (RPI). AKI was defined by the Kidney Disease Improving Global Outcome (KDIGO) criteria. The primary outcome was the diagnosis of severe AKI (KDIGO stage 2 or 3) on day 3. RESULTS: A total of 58 patients were included. Median age and weight were 12.9 months (IQR 6.0-37.9) and 7.36 kg (IQR 5.19-11.40), respectively. On day 3, 13 patients were classified as having AKI, of which 11 were severe. RRI could effectively predict AKI (area under the ROC curve [AUC] 0.83, 95% CI 0.71-0.92; p < 0.001) as well as RPI (AUC 0.81, 95% CI 0.69-0.90; p < 0.001). The optimal cutoff value for RRI was 0.85 (sensitivity, 73%; specificity, 83%; positive predictive value [PPV], 50%; and negative predictive value [NPV], 93%), while for RPI was 1.95 (sensitivity, 73%; specificity, 78%; PPV, 44%; and NPV, 92%). Similar results were found in the analysis for prediction on day 5. Significant correlations were found between Doppler-based variables and estimated GFR and furosemide dose on day 3. CONCLUSIONS: Kidney Doppler ultrasound may be a promising tool for predicting AKI in children undergoing cardiac surgery.

Linking Acute Physiology to Outcomes in the ICU: Challenges and Solutions for Research.

ICU clinicians rely on bedside physiological measurements to inform many routine clinical decisions. Because deranged physiology is usually associated with poor clinical outcomes, it is tempting to hypothesize that manipulating and intervening on physiological parameters might improve outcomes for patients. However, testing these hypotheses through mathematical models of the relationship between physiology and outcomes presents a number of important methodological challenges. These models reflect the theories of the researcher and can therefore be heavily influenced by one's assumptions and background beliefs. Model building must therefore be approached with great care and forethought, because failure to consider relevant sources of measurement error, confounding, coupling, and time dependency or failure to assess the direction of causality for associations of interest before modeling may give rise to spurious results. This paper outlines the main challenges in analyzing and interpreting these models and offers potential solutions to address these challenges.

Interaction between spiders and ticks-ancient arthropod predatory behavior?

Ticks are ectoparasite vectors of pathogens affecting human and animal health worldwide. Rational integration of different control interventions including plant-derived repellents and acaricides, management of natural predators, and vaccines is required for innovative approaches to reduce the risks associated with ticks and tick-borne diseases. How tick populations are naturally controlled is always a question. Tick interactions with other arthropods including predators evolved from ancient times. In this study, Cretaceous (ca. 100 Mya) Burmese amber inclusions were identified as probably related to Compluriscutula vetulum (Acari: Ixodida: Ixodidae) tick larvae and spider silk. As illustrated in this study, ancient interactions between ticks and spiders may support arthropod predatory behavior as a natural control intervention. Rational integrative management of different tick control interventions including natural predators under a One Health perspective will contribute to effectively and sustainably reducing the risks associated with ticks and tick-borne diseases.

Karyotypic changes and diversification time in Epinephelidae groupers (Perciformes). Implications on reproductive isolation.

Groupers (Epinephelidae and Serranidae) have attracted special attention to fish farming, and their species offer good opportunities for successful hybridizations. Cytogenetic data allow a better understanding of the role of karyotypic diversification in the acquisition of post-zygotic reproductive isolation (RI). Thus, chromosomal analyses were performed on E. striatus (Caribbean Sea), E. coioides and E. tauvina (Indo-Pacific Region), using standard procedures and mapping of six repetitive DNA classes by the in situ hybridization. The three species have 2n=48 chromosomes. The karyotypes of E. coioides and E. striatus are composed only of acrocentric chromosomes (FN=48), while E. tauvina has 8 submetacentric chromosomes (FN=56). Heterochromatin has a preferential centromeric distribution, and the microsatellite repeats are dispersed throughout the chromosomes of all species. The 18S and 5S rDNA sites are unique but show a colocalization arrangement in E. tauvina and E. striatus. The chromosomal organization suggests that the three species still maintain a significant amount of syntenic regions. The range of the karyotype divergence and the RI levels showed low, but goes turn proportionally greater in relation to the divergence time between the parental species. The slow acquisition of postzygotic RI is consistent with the high karyotype homogeneity presented by Epinephelidae family.

Intraoperative thermal mapping of mammary tumors in dogs.

In this study, videothermometry's application in detecting mammary tumors in dogs is explored in-depth. The research hypothesizes that this technique can effectively identify cancerous tissues during surgery by analyzing thermal patterns. The methodology involved comparing thermal imaging results from dogs with palpable mammary nodules against a control group, focusing on capturing real-time thermal patterns. Results were significant, showing distinct thermal patterns in carcinomas. This indicates videothermometry's capability in accurately identifying micro metastases and differentiating between neoplastic and non-neoplastic changes. The study concludes that videothermometry has considerable potential in enhancing surgical precision, especially in tumor resection and safety margin definition, but emphasizes the need for further research to thoroughly understand the thermal signatures of various mammary tumors in dogs.

Ticks infesting terrestrial small mammals in a rural settlement in the Amazonas state, Brazil.

There is limited knowledge about tick diversity in the Amazon region. Here, we survey small terrestrial mammals for tick infestation at the Rio Pardo settlement, Amazonas State, Brazil. Sampling included rainy and dry seasons and four ecotones (primary forest, forest in regeneration, field crops and households). Each animal was inspected for ticks, which, if present, were placed in 70% alcohol and identified. Parasitological indexes were calculated and the presence/absence of ticks on hosts was tested for possible associations with independent variables (ecotone, host sex, host order, host family, host age and season). A total of 208 small mammals were captured, 47 individuals (10 species) in the primary forest, 124 (15 species) in the forest in regeneration, 11 (7 species) in the field crops, and 26 (4 species) in the households. A total of 14 small mammals were infested by ticks (overall prevalence: 6.7%; 95% CI: 3.72 - 11.04%), which consisted of 51 specimens that were identified into four species, as follows: Amblyomma humerale (32 nymphs); Ixodes luciae (6 females); Amblyomma coelebs (1 nymph); and Ornithodoros mimon (1 larva). In addition, 11 larvae were retained as Amblyomma spp. Only host order showed association (P = 0.002) with tick infestation, with marsupials 5.5 times more infested than rodents. Our record of O. mimon on D. marsupialis is the first on this host species, and the first record of a Argasidae tick in the Brazilian state of Amazonas. To the best of our knowledge, this is the first study that actively screened free-living terrestrial small mammals and provided data on prevalence, mean intensity and mean abundance of tick infestations in the Brazilian Amazonas state.

Substantial Diversity in Cocirculating Omicron Lineages in Hospital Setting, Porto Alegre, Brazil.

We describe substantial variant diversity among 23 detected SARS-CoV-2 Omicron lineage viruses cocirculating among healthcare workers and inpatients (272 sequenced samples) from Porto Alegre, Brazil, during November 2022-January 2023. BQ.1 and related lineages (61.4%) were most common, followed by BE.9 (19.1%), first described in November 2022 in the Amazon region.

Bartonella spp. and Typhus Group Rickettsiae among Persons Experiencing Homelessness, São Paulo, Brazil.

Persons experiencing homelessness in São Paulo, Brazil, were seropositive for Bartonella spp. (79/109, 72.5%) and typhus group rickettsiae (40/109, 36.7%). Bartonella quintana DNA was detected in 17.1% (14/82) body louse pools and 0.9% (1/114) blood samples. Clinicians should consider vectorborne agents as potential causes of febrile syndromes in this population.

Secretory-IgA binding to intestinal microbiota attenuates inflammatory reactions as the intestinal barrier of preterm infants matures.

Previous work has shown that Secretory-IgA (SIgA) binding to the intestinal microbiota is variable and may regulate host inflammatory bowel responses. Nevertheless, the impact of the SIgA functional binding to the microbiota remains largely unknown in preterm infants whose immature epithelial barriers make them particularly susceptible to inflammation. Here, we investigated SIgA binding to intestinal microbiota isolated from stools of preterm infants <33 weeks gestation with various levels of intestinal permeability. We found that SIgA binding to intestinal microbiota attenuates inflammatory reactions in preterm infants. We also observed a significant correlation between SIgA affinity to the microbiota and the infant's intestinal barrier maturation. Still, SIgA affinity was not associated with developing host defenses, such as the production of mucus and inflammatory calprotectin protein, but it depended on the microbiota shifts as the intestinal barrier matures. In conclusion, we reported an association between the SIgA functional binding to the microbiota and the maturity of the preterm infant's intestinal barrier, indicating that the pattern of SIgA coating is altered as the intestinal barrier matures.

CellProfiler plugins - An easy image analysis platform integration for containers and Python tools.

CellProfiler is a widely used software for creating reproducible, reusable image analysis workflows without needing to code. In addition to the >90 modules that make up the main CellProfiler program, CellProfiler has a plugins system that allows for the creation of new modules which integrate with other Python tools or tools that are packaged in software containers. The CellProfiler-plugins repository contains a number of these CellProfiler modules, especially modules that are experimental and/or dependency-heavy. Here, we present an upgraded CellProfiler-plugins repository, an example of accessing containerised tools, improved documentation and added citation/reference tools to facilitate the use and contribution of the community.

Dynamic relative regional lung strain estimated by computed tomography and electrical impedance tomography in ARDS patients.

BACKGROUND: In the acute distress respiratory syndrome (ARDS), specific lung regions can be exposed to excessive strain due to heterogeneous disease, gravity-dependent lung collapse and injurious mechanical ventilation. Computed tomography (CT) is the gold standard for regional strain assessment. An alternative tool could be the electrical impedance tomography (EIT). We aimed to determine whether EIT-based methods can predict the dynamic relative regional strain (DRRS) between two levels of end-expiratory pressure (PEEP) in gravity-non-dependent and dependent lung regions. METHODS: Fourteen ARDS patients underwent CT and EIT acquisitions (at end-inspiratory and end-expiratory) at two levels of PEEP: a low-PEEP based on ARDS-net strategy and a high-PEEP titrated according to EIT. Three EIT-based methods for DRRS were compared to relative CT-based strain: (1) the change of the ratio between EIT ventilation and end-expiratory lung impedance in arbitrary units ([ΔZAU low-PEEP/EELIAU low-PEEP]/[ΔZAU high-PEEP/EELIAU high-PEEP]), (2) the change of ΔZ/EELI ratio calibrated to mL ([ΔZml low-PEEP/EELIml low-PEEP]/[ΔZml high-PEEP/EELIml high-PEEP]) using CT data, and (3) the relative change of ∆ZAU (∆ZAU low-PEEP/∆ZAU high-PEEP). We performed linear regressions analysis and calculated bias and limits of agreement to assess the performance of DRRS by EIT in comparison with CT. RESULTS: The DRRS assessed by (ΔZml low-PEEP/EELIml low-PEEP)/(ΔZml high-PEEP/EELIml high-PEEP) and ∆ZAU low-PEEP/∆ZAU high-PEEP showed good relationship and agreement with the CT method (R2 of 0.9050 and 0.8679, respectively, in non-dependent region; R2 of 0.8373 and 0.6588, respectively, in dependent region; biases ranging from - 0.11 to 0.51 and limits of agreement ranging from - 0.73 to 1.16 for both methods and lung regions). Conversely, DRRS based on EELIAU ([ΔZAU low-PEEP/EELIAU low-PEEP]/[ΔZAU high-PEEP/EELIAU high-PEEP]) exhibited a weak negative relationship and poor agreement with the CT method for both non-dependent and dependent regions (R2 ~ 0.3; bias of 3.11 and 2.08, and limits of agreement of - 2.13 to 8.34 and from - 1.49 to 5.64, respectively). CONCLUSION: Changes in DRRS during a PEEP trial in ARDS patients could be monitored using EIT, based on changes in ΔZmL/EELIml and ∆ZAU. The relative change ∆ZAU offers the advantage of not requiring CT data for calibration.

The Cosine Law to Choose the Correct Forceps Shaft Length for Macular Surgery in Highly Myopic Eyes.

PURPOSE: To demonstrate a mathematical analogy between the Pythagorean theorem using the axial a-scan measurement, i.e., the distance between the central cornea and the sclerotomy, and the lengths of the forceps in eyes of patients with all axial lengths. METHODS: We used the Pythagorean equation (c 2 = a 2 + b 2 ) to calculate the adequate shaft length of the forceps to use in macular surgery, especially in highly myopic eyes, where c 2 represents the axial length (hypotenuse); b 2 the sum of the corneal ray and distance between the corneal limbus and the sclerotomy (base side); and a 2 the distance between the sclerotomy and the fovea (perpendicular side). RESULTS: We reproduced the cosine law to estimate the distance between the sclerotomy and the fovea. The distance between the sclerotomy and the foveal area is shorter than the axial length and can become smaller based on the distance from the sclerotomy to the corneal limbus. CONCLUSION: This simple mathematical formula is useful when performing surgery in highly myopic eyes, in which there can be difficulties reaching the macular area.

Accuracy of Respiratory Variation in Inferior Vena Cava Diameter to Predict Fluid Responsiveness in Children Under Mechanical Ventilation.

Proper assessment of fluid responsiveness using accurate predictors is crucial to guide fluid therapy and avoid the serious adverse effects of fluid overload. The main objective of this study was to investigate the accuracy of respiratory variations in inferior vena cava diameter (∆IVC) to predict fluid responsiveness in mechanically ventilated children. This prospective single-center study included 32 children (median age and weight of 17 months and 10 kg, respectively) who received a fluid infusion of 10 ml kg-1 of crystalloid solutions over 10 min. ∆IVC and respiratory variation in aortic blood flow peak velocity (∆Vpeak) were determined over one controlled respiratory cycle before and after fluid loading. Thirteen (41%) participants were fluid-responders. ∆IVC, ∆Vpeak, stroke volume index, and cardiac index were found to be predictors of fluid responsiveness. However, the area under the ROC curve of ∆IVC was smaller when compared to ∆Vpeak (0.709 vs. 0.935, p < 0.012). The best cut-off values were 7.7% for ∆IVC (sensitivity, 69.2%; specificity 78.9%, positive predictive value, 69.2%; and negative predictive value, 78.9%) and 18.2% for ∆Vpeak (sensitivity, 84.6%; specificity, 89.5%; positive predictive value, 84.6%; negative predictive value, 89.5%). Changes in stroke volume were positively correlated with ∆IVC (ρ = 0.566, p < 0.001) and ∆Vpeak (ρ = 0.603, p < 0.001). A significant correlation was also found between changes in MAP and ∆Vpeak (ρ = 0.382; p = 0.031), but the same was not observed with ∆IVC (ρ = 0.011; p = 0.951). In conclusion, ∆IVC was found to have a moderate accuracy in predicting fluid responsiveness in mechanically ventilated children and is an inferior predictor when compared to ∆Vpeak.