Background: Hypoxia can affect the health and safety of patients and persons in various occupations. There is uncertainty surrounding the effect acute hypoxia may have on cognition and the cardiovascular system.Aims: The aim was to examine cognition using the Wechsler Abbreviated Scale of Intelligence -First Edition (WASI-I) and investigate heart rate variability (HRV) with varied fraction of inspired oxygen (FiO2) of 0.12, 0.165, and 0.21. Methods: Seventeen healthy volunteers participated in two tasks of the WASI-I: block design (BD) and matrix reasoning (MR). BD, MR, and HRV were measured during randomized gas interventions. A subset had their cerebral tissue oxygenation levels (TOI) evaluated.Results: Cognitive tests for BD (p = 0.133) and MR (p = 0.237) were not significantly different under different O2 concentrations. HRV data showed a decrease in high frequency (HFnu) for MR subset (p = 0.001) with decreasing FiO2. Mean heart rate for BD (p = 0.016) and MR (p = 0.007) increased with decreasing FiO2. NIRS data showed the mean TOI did not significantly change (p = 0.611) during BD; however, during MR, TOI (p = 0.003) decreased with lowering FiO2.Conclusions: Parasympathetic activity and cerebral tissue oxygenation both fell during MR with increasing hypoxia. The cognitive tests did show decreasing trends, albeit non-significant, with increasing severity of hypoxia. HR also increased during hypoxia for both BD and MR. We suspect cognitive function is related to oxygen saturation (SpO2) levels.

Background Left ventricular free wall rupture (LVFWR) and interventricular septal rupture (VSR) are potentially catastrophic mechanical complications after acute myocardial infarction (AMI). When they occur together, “double myocardial rupture” (DMR), survival is unlikely. DMR is seen in only 0.3% of all AMIs. With or without surgical intervention, the odds are against the patient. Case presentation A 57-year-old male self-referred to the emergency department of a remote hospital 5 days after first experiencing chest pain. Investigations in ED confirmed an inferior ST-segment elevation myocardial infarction (STEMI) complicated by DMR. Coronary angiography revealed a mid-course total occlusion of the right coronary artery (RCA). He was rapidly transferred to our regional cardiac surgical unit, arriving straight into the operating theatre, in cardiogenic shock. He was briefly conscious, before arresting prior to intubation and being massaged onto bypass. Not only did he survive the all-night operation, requiring a mitral valve replacement in the process, but he survived multiple postoperative complications to be eventually transferred on postoperative day 66, neurologically intact, to a peripheral unit to complete his rehabilitation. He was subsequently discharged home 88 days after the operation and was able to ambulate with a walking frame into his first postoperative follow-up clinic appointment. Conclusions Our patient, against all odds, has survived DMR and multiple postoperative complications. We present the details of his case and the literature surrounding the condition. The patient’s mental fortitude and his supportive family played a big part, along with excellent team working in our unit.