RESUMO
OBJECTIVES: Transcutaneous cardiac pacing (TCP) is a potentially lifesaving therapy for patients who present in the prehospital setting with bradycardia that is causing hemodynamic compromise. Our objective was to examine the outcomes of patients who received prehospital TCP and identify predictors of TCP failure. METHODS: We utilized the 2018-2021 ESO Data Collaborative public use research datasets for this study. All patients without a documented TCP attempt were excluded. Mortality was derived from hospital disposition data. TCP failure was defined as initiation of CPR following the first TCP attempt among patients who did not receive CPR prior to the first TCP attempt. Multivariable logistic regression models using age and sex as covariables were used to explore the association between prehospital vital signs and TCP failure. RESULTS: During the study period, 13,270 patients received transcutaneous pacing and 2,560 of these patients had outcome data available. Overall, the mortality rate following TCP was 63.4%. Among patients who did not receive CPR prior to the first TCP attempt (n = 7,930), TCP failure (progression to cardiac arrest) occurred 20.4% of the time. Factors associated with TCP failure included increased body weight (>100 vs. 60-100 kg, aOR: 1.33 (1.15, 1.55)), a pre-pacing non-bradycardic heart rate (>50 vs. <40 bpm, aOR: 2.87 (2.39, 3.44)), and pre-TCP hypoxia (<80% vs. >90% SpO2, aOR: 6.01 (4.96, 7.29)). CONCLUSIONS: Patients who undergo prehospital TCP are at high risk of mortality. Progression to cardiac arrest is common and associated with factors including increased weight, a non-bradycardic initial heart rate and pre-TCP hypoxia.
RESUMO
Drought causes substantial reductions in crop yields worldwide. Therefore, we set out to identify new chemical and genetic factors that regulate drought resistance in Arabidopsis thaliana. Karrikins (KARs) are a class of butenolide compounds found in smoke that promote seed germination, and have been reported to improve seedling vigor under stressful growth conditions. Here, we discovered that mutations in KARRIKIN INSENSITIVE2 (KAI2), encoding the proposed karrikin receptor, result in hypersensitivity to water deprivation. We performed transcriptomic, physiological and biochemical analyses of kai2 plants to understand the basis for KAI2-regulated drought resistance. We found that kai2 mutants have increased rates of water loss and drought-induced cell membrane damage, enlarged stomatal apertures, and higher cuticular permeability. In addition, kai2 plants have reduced anthocyanin biosynthesis during drought, and are hyposensitive to abscisic acid (ABA) in stomatal closure and cotyledon opening assays. We identified genes that are likely associated with the observed physiological and biochemical changes through a genome-wide transcriptome analysis of kai2 under both well-watered and dehydration conditions. These data provide evidence for crosstalk between ABA- and KAI2-dependent signaling pathways in regulating plant responses to drought. A comparison of the strigolactone receptor mutant d14 (DWARF14) to kai2 indicated that strigolactones also contributes to plant drought adaptation, although not by affecting cuticle development. Our findings suggest that chemical or genetic manipulation of KAI2 and D14 signaling may provide novel ways to improve drought resistance.