Platypnea-orthodeoxia syndrome is characterised by hypoxemia and dyspnoea while upright that resolves when supine, typically associated with an interatrial communication. We present a case of platypnea-orthodeoxia syndrome associated with a sinus venosus atrial septal defect in a patient with multiple possible aetiologies of hypoxemia, including COVID-19 infection. Cardiac catheterisation with provocative maneuvers confirmed the diagnosis and symptoms resolved following defect closure. We suggest that in patients with platypnea-orthodeoxia syndrome, it is useful to obtain haemodynamic data while supine and upright

This study assessed the welfare of rats (Rattus norvegicus) poisoned with a lethal dose of the methaemoglobin (MetHb) inducing compound para-aminovalerophenone (PAVP). Twenty rats were orally gavaged with either PAVP (treated) or the vehicle only (control). Spontaneous and evoked behaviours were recorded and blood samples collected post mortem for analysis of MetHb%. Female and male rats received a mean (± SEM) dose of 263 (± 3) and 199 (± 6) mg PAVP kg−1, respectively. Mean (± SEM) time to death was 67 (± 16) and 354 (± 71) min for female and male rats, respectively. Control animals did not show any signs of intoxication. The time to death from methaemoglobinaemia in rats was significantly shorter than that reported for anticoagulants and there were no obvious signs of distress or pain.

In a series of experiments the welfare of para-aminovalerophenone (PAVP) sub-lethally poisoned rats (Rattus norvegicus) was assessed. The experiments: (i) examined the acute methaemoglobin (MetHb) profile over time; (ii) refined the LD50 estimate for PAVP in adult female rats; (iii) developed and validated three neurological tests; and (iv) assessed rats for neurological deficit following prolonged methaemoglobinaemia. The results from the first three experiments were used to refine the sub-lethal study. In the sub-lethal experiment 20 rats were gavaged with a single dose of 40 mg kg−1 PAVP (based on an LD50 estimate of 43.3 mg kg−1). Control rats (n = 10) were treated with the carrier only. Eleven (surviving) PAVP-treated rats and controls were assessed over a two-week period. Rats were tested for forelimb grip strength, stability on an inclined plane and the ability to remove tape wrapped around a forepaw in order to determine deficits in motor functions and sensorimotor integration. Signs of recovery began 3-6 h post-dosing, with all animals showing no outward signs of poisoning within 48 h, and over the 14-day post-treatment monitoring period they gained weight and increased their food consumption. There was no significant overall difference in performance between PAVP-treated and control rats in any of the three neurological tests. In the inclined plane test, performance of sub-lethally PAVP-poisoned rats appeared to be temporarily impaired with treated animals slipping at a lower angle than controls on day two. During the tape removal test, four PAVP-treated rats failed to remove the tape within the 3-min time limit on one occasion each (4/77 occasions) up to seven days post-dosing. The severity and duration of signs following acute sub-lethal PAVP poisoning appeared to be lower than those reported for existing rodenticides. It is likely that the results presented in this study extend to other MetHb-inducers.

Pheochromocytoma/paraganglioma is an exceedingly rare tumour, thought to share an association with cyanotic CHD. This association is thought to be a result of chronic hypoxaemia (Antonio et al, Revista Española de Cardiología (English Edition) 2017; 70: 673–675; Folger et al, Circulation 1964; 29: 750–757; Opotowsky et al, J Clin Endocrinol Metab 2015; 100: 1325–1334) We report two cases of paraganglioma over a 4-year period in patients with hypoplastic left heart syndrome who had undergone Fontan completion by ages 2 and 4. Based on a very small number of reported cases of CHD, the mechanism of tumourigenesis is unclear. It is imperative that cases associated with CHD continue to be reported so that we may learn more about the pathogenesis and epidemiology of this entity.

Introduction: CHD patients, especially those with associated hypoxaemia, usually have some level of renal function impairment, even though they are relatively young. The aim of the study was to evaluate those clinical and analytical factors that may contribute to microalbuminuria and determine the association of 24-hour proteinuria with thrombotic events and mortality. Methods: A total of 251 CHD patients were studied and demographic characteristics, blood test, and 24-hour urinalysis were analysed. Results: Of the patients, 221 were non-hypoxaemic, and 30 were hypoxaemic (oxygen saturation of 84.3±5.9%). Of the non-hypoxaemic patients, 30 (13.6%), and of the hypoxaemic patients 9 (30%), showed proteinuria (>0.15 g/24 hours) (p=0.028). Hypoxaemic CHD patients also showed higher haematocrit (%) (50.7 (34.6; 72.1) versus 42.8 (34.6; 48.9), p<0.001), serum creatinine (mg/dl) (1.07±0.2 versus 0.96±1.9, p=0.004), microalbuminuria (mg/dl/24 hours) (1.2 (0.0; 261.5) versus 0.5 (0.0; 4.37), p<0.001), proteinuria (gr/24 hours) (1.0 (0.4; 3.1) versus 0.08 (0.04; 0.52), p=0.043), and N-terminal pro–B-type natriuretic peptide (pg/ml) (417.8 (35.7; 8534.0) versus 44.9 (0.0; 670.5), p<0.001) concentrations than non-hypoxaemic CHD patients. During a median follow-up of 26.0 (16.9; 57.7) months, five patients died – one patient had 24-hour proteinuria and four patients did not (p=0.581) – and three patients had some type of thrombosis – two patients had 24-hour proteinuria and one patient did not (p=0.014). Kaplan–Meier survival analysis showed no significant difference between CHD patients with and without 24-hour proteinuria (p=0.631). Conclusion: CHD patients with proteinuria have significantly more thrombosis and more hypoxaemia than those patients without proteinuria.

High altitude acclimatization produces a suite of physiological changes that might support an improved athletic performance at low altitude and thus lead to the strategy of athletic training at high altitude. Although there is substantial literature on high altitude physiology in humans, there are few studies on horses. Our interest in the physiological responses to high altitude in equids has been driven by the concerns of how athletic performance is altered at altitude and how conditioning at altitude may improve performance subsequently at low altitude. This review serves to illustrate what is currently know about the physiological changes of horses to altitude, at rest and during exercise, and to highlight how performance is impacted both at high altitude and subsequent return to low altitude.

The relation between intra-operative gas exchange and post-operative oxygen saturation was examined using pulse oximetry (SpO2) 30 h after anaesthesia for upper abdominal surgery. The inspired oxygen partial pressure (PIO2) was varied during anaesthesia to produce a plot of PIO2 vs. SpO2. Gas exchange during anaesthesia was inferred from the relation between PIO2 and SpO2 which was described by its lateral and vertical displacement away from the position of a standard oxygen dissociation curve. With patients breathing air, the SpO2 was measured over a 10-min period at 30 h after surgery. The correlation coefficient of the lateral displacement with post-operative SpO2 was 0.7, and that of the vertical displacement with post-operative SpO2 was 0.66. The correlation coefficient of intra-operative SpO2 at PIO2 = 21 kPa with post-operative SpO2 was 0.69. It can be concluded that gas exchange abnormalities during anaesthesia deduced from the displacement of the PIO2 vs. SpO2 curve correlate with SpO2 30 h post-operatively and may help to identify patients at risk of post-operative hypoxaemia.