Introduction
Abnormalities in magnesium concentration are common in critically ill humans and are associated with increased mortality in hypoxic-ischemic encephalopathy (HIE) patients. Total plasma magnesium concentrations are significantly higher in perinatal asphyxia syndrome neonatal foals compared to healthy, septic and premature foals. Scant information is published about ionized magnesium concentrations [iMg] in critically ill neonatal foals. The aim was to compare plasma [iMg] in healthy neonatal, septic and critically ill non-septic foals, and to identify associations between diagnosis or outcome with magnesium disorders.
Methods
Observational prospective study in an equine referral hospital. Blood samples were collected in lithium heparin tubes upon admission to the hospital from 2019 to 2021 to determine [iMg] with a benchtop co-oximetry and electrolytes analyzer. In addition, blood samples from healthy neonatal foals were obtained within 24-48 h after birth from a nearby stud farm. Data was summarized by descriptive statistics and one-way ANOVA was used to compare groups.
Results
Twenty-three neonatal foals of ≤14 days were enrolled (mean age 2.6 d), and classified as septic (n=6, mean 4.3 days), sick non-septic (n=11, mean 2.4 d; HIE n=7, 1.9 d), and foals not requiring intensive treatment (n=6, mean 1.3 d). In addition, twenty-one healthy neonatal foals (<2 d) were included as a control group. One out of 6 septic foals and 7 out of 11 nonseptic critically ill foals did not survive. The [iMg] in healthy foals was 0.42–0.91 mmol/L (95% confidence interval). No significant differences were noted in [iMg] comparing septic (0.58±0.15 mmol/L; mean±SD), sick nonseptic (0.57±0.10 mmol/L) and healthy groups (0.66±0.12 mmol/L; p=0.53). No significant differences were observed in [iMg] between critically ill survivors (0.53±0.08 mmol/L; mean±SD) and non-survivors (0.62±0.14 mmol/L; p=0.12). Only one septic foal (16%) presented hypomagnesemia (0.38 mmol/L).
Conclusions
[iMg] in healthy neonatal foals was similar to healthy adult horses (0.4–0.6 mmol/L), but a higher variability was observed. No differences were seen in [iMg] between groups, neither in the HIE foals. These results could be partly influenced by the small size of the groups. Finally, [iMg] was not associated with outcome. Further research is required to confirm these findings.
Disclosures
Disclosures to report: Study supported by Nova Biomedical Corp.