The effect of preoperative magnesium supplementation on blood catecholamine concentrations in patients undergoing CABG.
ABSTRACT It is well known that magnesium (Mg) plays an important role in many physiological processes such as regulation of blood catecholamine concentrations, particularly epinephrine (E) and norepinephrine (NE). The complex character of extracorporeal circulation (ECC) with intraoperative normovolemic haemodilution (NH) may alter blood Mg levels, which is likely to result in disorders of E and NE. The aim of this study was to analyze the influence of preoperative Mg supplementation on E and NE in patients undergoing CABG.
Forty male patients undergoing CABG under general anaesthesia were included. Patients were randomly divided into two groups: A--the patients receiving pre-operative magnesium supplementation and B--patients without pre-operative magnesium supplementation. The Mg, E and NE blood concentrations were measured in five stages: 1) before anesthesia after the radial artery cannulation, 2) during NH and ECC, 3) immediately after surgery, 4) in the morning of the 1st postoperative day, 5) in the morning of the 2nd postoperative day. The Mg levels were determined by spectrophotometric methods, E and NE were measured by radioimmunoassay methods.
The CABG caused a decrease of Mg and an increase of E and NE in both groups, but the changes were significantly higher in group B.
1) CABG causes a decrease of Mg and an increase of E and NE; 2) Preoperative, oral supplementation of Mg substantially reduces intra- and postoperative disorders.
SourceAvailable from: Silvia Izquierdo Alvarez
Article: Silvia Izquierdo Álvarez, Alicia Boudet García, Santiago Otero Martínez, María Dolores Fernández González, Joaquín González Revaldería, Ángel García De Jalón Comet, Jesús Fernando Escanero Marcén. Estimation of precision and inaccuracy for serum magnesium determination on the basis of interlaboratory comparison data Accreditation ISO 15189. Magnesium Research 2008; 21 (1): 51-7Magnesium research: official organ of the International Society for the Development of Research on Magnesium 01/2008; · 1.56 Impact Factor
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ABSTRACT: In conclusion, electrolyte disorders are common in cardiovascular patients and complicate the care of these patients. The vigilant nurse expects electrolyte abnormalities in their patients and assesses for signs and symptoms related to them. The symptomatology of electrolyte disorders can be vague or the patient's symptoms may have multiple causes. Therefore, the nurse should always assess for the most recent laboratory work available for patients and be alert for changes in electrolyte values. Cardiac monitoring is indicated for these patients because many electrolyte disorders can contribute to cardiac arrhythmias or may cause electrocardiographic changes.Critical care nursing clinics of North America 12/2011; 23(4):635-43. DOI:10.1016/j.ccell.2011.08.008 · 0.43 Impact Factor
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ABSTRACT: The purpose of the study was to analyse the effects of different forms of magnesium supplementation on its serum concentrations and the frequency of atrial fibrillation in patients undergoing coronary artery bypass graft surgery with extracorporeal circulation (ECC). One hundred and twenty adult patients were examined. All of them received intravenous infusions of MgSO4 during surgery and the early postoperative period (18 hours). Moreover, some of them received preoperative Mg supplementation. Therefore, patients were divided into six groups: A) patients, receiving an intravenous infusion 3.33 mg of MgSO4 per min; B) those receiving preoperative, oral Mg supplementation (OPS-Mg) and intravenous 3.33 mg of MgSO4 per min; C) patients receiving intravenous 6.66 mg of MgSO4 per min; D) patients receiving OPS-Mg and 6.66 mg of MgSO4 per min; E) patients receiving intravenous 10 mg of MgSO4 per min; F) those receiving OPS-Mg and 10 mg of MgSO4 per min. Additionally, all patients were divided into three groups: O (patients, who did not receive dopamine or dobutamine infusions), DOP (those receiving dopamine infusions in doses dependent on their clinical state) and DOB (those receiving dobutamine infusions in doses dependent on their clinical state). Total serum Mg concentrations (Mg(t)) were measured at five points: 1) 10 min before anaesthesia; 2) 10 min after ECC; 3) 10 min after surgery, 4) in the morning of postoperative day 1, 5) in the morning of postoperative day 2. The data were analyzed statistically; values at the first measurement points were considered as baseline. In group A, Mg(t) decreased at time points 2, 3, 4. Similar changes were observed in group B, however, in both groups Mg(t) returned to the baseline value at time point 5. In groups C and D, Mg(t) decreased at point 2 and 3, whereas in groups E and F it was increased during all the study period. The changes in Mg(t) were slightly less in patients receiving OPS-Mg, these patients had a significantly higher Mg(t) at time point 1. Mg(t) decreased in the O, DOP and DOB groups at measurement points 2 and 3. Moreover, the lowest Mg(t) was observed in the DOP group. Atrial fibrillation (AF) was noted in 33 patients (27.5%). The highest percentage of patients with AF during the early postoperative days was observed in groups A and B (45%). In groups C, D, E and F, AF was detected in 25%, 20%, 20% and 10% of patients, respectively. The incidence of AF was significantly higher in groups A and B compared to the other groups. Moreover, episodes of AF were rarer in patients receiving preoperative, oral Mg supplementation. Conclusions: 1) ECC resulted in a decrease in Mg(t); 2) Mg infusion at the dose of 3.33 mg/min had little effect for the prevention of postoperative AF; 3) the infusion of 10 mg/min of MgSO4 maintained the level of Mg(t) during CABG and most effectively reduced AF; 4) OPS-Mg played a beneficial role in Mg(t) disturbances during CABG; 5) dopamine caused the most severe disturbances in serum Mg(t) concentration.Magnesium research: official organ of the International Society for the Development of Research on Magnesium 01/2009; 21(4):205-17. · 1.56 Impact Factor