Tehran University of Medical Sciences Archives of Anesthesiology and Critical Care 2423-5849 5 3 2019 07 02 86 90 Amin Assarian Department of Clinical Pharmacy, School of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran. Afsaneh Noormandi Department of Clinical Pharmacy, School of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran. Hossein Khalili Department of Clinical Pharmacy, School of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran. Mostafa Mohammadi Department of Intensive Care Unit, Imam Khomeini Hospital, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. Alireza Abdollahi Department of Pathology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. 2019 07 02 Background: As the fourth abundant electrolyte in the body, magnesium has critical roles in aerobic metabolism and regulation of the immune system. Few studies investigate the association between magnesium status of critically ill septic patients and lactate acidosis in the intensive care unit (ICU). In this study, serum magnesium level and lactate level were evaluated at both admission time and time of sepsis. Methods: This was a prospective, cross-sectional study conducted at general ICU of a tertiary referral teaching hospital. Hypomagnesemia was defined as a serum magnesium concentration of less than 1.7 mg/dL. Mann-Whitney test and independent-sample t-test were used to analyze nonparametric and parametric data, respectively. Results: Of 50 sepsis patients, 32 patients were normomagnesemic, and 18 were hypomagnesemic. Hypomagnesemic patients have significantly higher lactate serum level at the time of sepsis compared to normomagnesemic patients [2.32 (1.96-3.29) vs. 1.94 (1.80-2.15) mg/dl respectively, p<0.001]. There were significant differences between normomagnesemic and hypomagnesemic septic patients in Acute Physiology and Chronic Health Evaluation (APACHE) II score at sepsis time (9.44 ± 4.33 vs. 11.67 ± 3.83, p=0.46), and Sequential Organ Failure Assessment (SOFA) score [3 (3.00-5.00) vs. 4 (3.75-6.25), p=0.04]. Also, 28-day mortality because of sepsis (50% respectively, p<0.001), duration of mechanical ventilation [12.00 (4.00-14.25) days respectively, p<0.01] and ICU stay [14.00 (12.75-17.25) days respectively, p<0.01] were significantly higher in hypomagnesemic groups. Conclusion: Admission hypomagnesemia in sepsis patients may increase serum lactate concentration, duration of ventilation, duration of ICU stay and mortality. https://aacc.tums.ac.ir/index.php/aacc/article/view/240 https://aacc.tums.ac.ir/index.php/aacc/article/download/240/418