Renal cortical oxygen tension is decreased following exposure to long-term but not short-term intermittent hypoxia in the rat.

Chronic kidney disease (CKD) occurs in more than 50% of patients with obstructive sleep apnea (OSA). However, the impact of intermittent hypoxia (IH) on renal function and oxygen homeostasis is unclear. Male Sprague-Dawley rats were exposed to IH (270 s at 21% O2; 90 s hypoxia, 6.5% O2 at nadir) for 4 h [acute IH (AIH)] or to chronic IH (CIH) for 8 h/day for 2 wk. Animals were anesthetized and surgically prepared for the measurement of mean arterial pressure (MAP), and left renal excretory function, renal blood flow (RBF), and renal oxygen tension (Po2). AIH had no effect on MAP (123 ± 14 vs. 129 ± 14 mmHg, means ± SE, sham vs. IH). The CIH group was hypertensive (122 ± 9 vs. 144 ± 15 mmHg, P < 0.05). Glomerular filtration rate (GFR) (0.92 ± 0.27 vs. 1.33 ± 0.33 ml/min), RBF (3.8 ± 1.5 vs. 7.2 ± 2.4 ml/min), and transported sodium (TNa) (132 ± 39 vs. 201 ± 47 µmol/min) were increased in the AIH group (all P < 0.05). In the CIH group, GFR (1.25 ± 0.28 vs. 0.86 ± 0.28 ml/min, P < 0.05) and TNa (160 ± 39 vs. 120 ± 40 µmol/min, P < 0.05) were decreased, while RBF (4.13 ± 1.5 vs. 3.08 ± 1.5 ml/min) was not significantly different. Oxygen consumption (QO2) was increased in the AIH group (6.76 ± 2.60 vs. 13.60 ± 7.77 µmol/min, P < 0.05), but it was not significantly altered in the CIH group (3.97 ± 2.63 vs. 6.82 ± 3.29 µmol/min). Cortical Po2 was not significantly different in the AIH group (46 ± 4 vs. 46 ± 3 mmHg), but it was decreased in the CIH group (44 ± 5 mmHg vs. 38 ± 2 mmHg, P < 0.05). For AIH, renal oxygen homeostasis was preserved through a maintained balance between O2 supply (RBF) and consumption (GFR). For CIH, mismatched TNa and QO2 reflect inefficient O2 utilization and, thereby, sustained decrease in cortical Po2.

Successful maintenance of process and outcomes for oesophageal cancer surgery in Ireland during the first wave of the COVID-19 pandemic.

INTRODUCTION: The emergence of the novel coronavirus Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) and the coronavirus disease COVID-19 has impacted enormously on non-COVID-19-related hospital care. Curtailment of intensive care unit (ICU) access threatens complex surgery, particularly impacting on outcomes for time-sensitive cancer surgery. Oesophageal cancer surgery is a good example. This study explored the impact of the pandemic on process and short-term surgical outcomes, comparing the first wave of the pandemic from April to June in 2020 with the same period in 2019. METHODS: Data from all four Irish oesophageal cancer centres were reviewed. All patients undergoing resection for oesophageal malignancy from 1 April to 30 June inclusive in 2020 and 2019 were included. Patient, disease, and peri-operative outcomes (including COVID-19 infection) were compared. RESULTS: In 2020, 45 patients underwent oesophagectomy, and 53 in the equivalent period in 2019. There were no differences in patient demographics, co-morbidities, or use of neoadjuvant therapy. The median time to surgery from neoadjuvant therapy was 8 weeks in both 2020 and 2019. There were no significant differences in operative interventions between the two time periods. There was no difference in operative morbidity in 2020 and 2019 (28% vs 40%, p = 0.28). There was no in-hospital mortality in either period. No patient contracted COVID-19 in the perioperative period. CONCLUSIONS: Continuing surgical resection for oesophageal cancer was feasible and safe during the COVID-19 pandemic in Ireland. The national response to this threat was therefore successful by these criteria in the curative management of oesophageal cancer.