Heatstroke presentations to urban hospitals during BC's extreme heat event: lessons for the future

BACKGROUND

Climate change is leading to more extreme heat events in temperate climates that typically have low levels of preparedness. Our objective was to describe the characteristics, treatments, and outcomes of adults presenting to hospitals with heatstroke during BC's 2021 heat dome.

METHODS

We conducted a review of consecutive adults presenting to 7 hospitals in BC's Lower Mainland. We screened the triage records of all patients presenting between June 25th and 30th, 2021 for complaints related to heat, and reviewed the full records of those who met heatstroke criteria. Our primary outcome was in-hospital mortality. We used Mann-Whitney U tests and logistic regression to investigate associations between patient and treatment factors and mortality.

RESULTS

Among 10,247 consecutive presentations to urban hospitals during the extreme heat event, 1.3% (139; 95% confidence intervals [CI] 1.1-1.6%) met criteria for heatstroke. Of heatstroke patients, 129 (90.6%) were triaged into the two highest acuity levels. Patients with heatstroke had a median age of 84.4 years, with 122 (87.8%) living alone, and 101 (84.2%) unable to activate 911 themselves. A minority (< 5, < 3.6%) of patients presented within 48 h of the onset of extreme heat. Most patients (107, 77.0%) required admission, and 11.5% (16) died in hospital. Hypotension on presentation was associated with mortality (odds ratio [OR] 5.3).

INTERPRETATION

Heatstroke patients were unable to activate 911 themselves, and most presented with a 48-h delay. This delay may represent a critical window of opportunity for pre-hospital and hospital systems to prepare for the influx of high-acuity resource-intensive patients.

Silencing circPalm2 inhibits sepsis-induced acute lung injury by sponging miR-376b-3p and targeting MAP3K1

The apoptosis and inflammation of pulmonary epithelial cells are important pathogenic factors of sepsis-induced acute lung injury (ALI). Upregulation of circPalm2 (circ_0001212) expression levels has been previously detected in the lung tissue of ALI rats. Herein, the biological significance and detailed mechanism of circPalm2 in ALI pathogenesis were investigated. In vivo models of sepsis-induced ALI were established by treating C57BL/6 mice with cecal ligation and puncture (CLP) surgery. Murine pulmonary epithelial cells (MLE-12 cells) were stimulated with lipopolysaccharide (LPS) to establish in vitro septic ALI models. MLE-12 cell viability and apoptosis were evaluated by CCK-8 assay and flow cytometry analysis, respectively. The pathological alterations of the lung tissue were analysed based on hematoxylin-eosin (H&E) staining. Cell apoptosis in the lung tissue samples was examined by TUNEL staining assay. LPS administration suppressed the viability and accelerated the inflammation and apoptotic behaviours of MLE-12 cells. CircPalm2 displayed high expression in LPS-stimulated MLE-12 cells and possessed circular characteristics. The silencing of circPalm2 impeded apoptosis and inflammation in LPS-stimulated MLE-12 cells. Mechanistically, circPalm2 bound with miR-376b-3p, which targeted MAP3K1. In rescue assays, MAP3K1 enhancement reversed the repressive effects of circPalm2 depletion on LPS-triggered inflammatory injury and MLE-12 cell apoptosis. Furthermore, the lung tissue collected from CLP model mice displayed low miR-376b-3p expression and high levels of circPalm2 and MAP3K1. CircPalm2 positively regulated MAP3K1 expression by downregulating miR-376b-3p in murine lung tissues. Importantly, circPalm2 knockdown attenuated CLP-induced inflammation, apoptosis, and pathological alterations in lung tissues collected from mice. Silenced circPalm2 inhibits LPS-induced pulmonary epithelial cell dysfunction and mitigates abnormalities in lung tissues collected from CLP-stimulated mice via the miR-376b-3p/MAP3K1 axis in septic ALI.

Supplementary Information

The online version contains supplementary material available at 10.1007/s43188-022-00169-7.