Magnesium therapy improves thromboelastographic findings before liver transplantation: A preliminary study

The hemostatic performance and mechanism of palygorskite with structural regulate by oxalic acid gradient leaching

Palygorskite (Pal) is a naturally available one-dimensional clay mineral, featuring rod-shaped morphology, nanoporous structure, permanent negative charges as well as abundant surface hydroxyl groups, exhibiting promising potential as a natural hemostatic material. In this study, the hemostatic performance and mechanisms of Pal were systematically investigated based on the structural regulate induced by oxalic acid (OA) gradient leaching from perspectives of structure, surface attributes and ion release.In vitroandin vivohemostasis evaluation showed that Pal with OA leaching for 1 h exhibited a superior blood procoagulant effect compared with the raw Pal as well as the others leached for prolonging time. This phenomenon might be ascribed to the synergistic effect of the intact nanorod-like morphology, the increase in the surface negative charge, the release of metal ions (Fe3+and Mg2+), and the improved blood affinity, which promoted the intrinsic coagulation pathway, the fibrinogenesis and the adhesion of blood cells, thereby accelerating the formation of robust blood clots. This work is expected to provide experimental and theoretical basis for the construction of hemostatic biomaterials based on clay minerals.

Higher Doses of Calcium Associated With Survival in Trauma Patients

INTRODUCTION

Calcium is required for coagulation, cardiac output, and peripheral vascular resistance. Between 85% and 94% of trauma patients treated with massive blood transfusion develop hypocalcemia.1 The aim of this study is to evaluate the relationship between increased intravenous calcium administration during massive transfusion and improved survival of trauma patients.

METHODS

We performed a retrospective analysis of trauma patients who received massive transfusion over a 2-y period. Doses of elemental calcium administered per unit of blood product transfused were calculated by calcium to blood product ratio (CBR). Chi-square test evaluated association between coagulopathy and 30-d mortality. Two-sample t-test evaluated association between CBR and coagulopathy. Bivariate regression analysis evaluated association between CBR and blood products transfused per patient. Multivariable logistic regression analysis, controlling for age, sex, coagulopathy, and Injury Severity Score evaluated the association between CBR and mortality.

RESULTS

The study included 77 patients. Coagulopathy was associated with increased 30-d mortality (P < 0.05). Patients who survived had higher CBR than those who died (P < 0.05). CBR was associated with a significant reduction in total blood products transfused per patient (P < 0.05). CBR was not associated with coagulopathy (P = 0.24). Multivariable logistic regression analysis demonstrated that Injury Severity Score ≥16, coagulopathy and decreased CBR were significant predictors of mortality (P < 0.05). CBR above 50 mg was a predictor of survival (P < 0.05).

CONCLUSIONS

Higher doses of calcium given per blood product transfused were associated with improved 30-d survival and decreased blood product transfusions.

Abnormal serum Magnesium Level is Associated with the Coagulopathy in Traumatic Brain Injury Patients

BACKGROUND

Coagulopathy is associated with poor prognosis of traumatic brain injury (TBI) patients. This study is performed to explore the association between serum magnesium level and the risk of coagulopathy in TBI.

METHODS

TBI patients from the Medical Information Mart for Intensive Care-III database were included for this study. Logistic regression analysis was performed to explore risk factors and develop a predictive model for coagulopathy in TBI. The restricted cubic spline (RCS) was utilized to analyze the association between serum magnesium level and the development of coagulopathy. Receiver operating characteristic curve was drawn to evaluate the performance of the predictive model for coagulopathy.

RESULTS

The incidence of coagulopathy in TBI was 32.6%. The RCS indicated the association between magnesium and coagulopathy was U-shaped. Multivariate logistic regression confirmed age, coronary heart disease, cerebral vascular disease, chronic liver disease, GCS, ISS, epidural hematoma, hemoglobin, shock index and magnesium level were independently associated with the coagulopathy in TBI. Compared with patients of magnesium level between 1.7 and 2.3 mg/dL, those with magnesium level below 1.7 mg/dL or above 2.2 mg/dL had a higher risk of coagulopathy.

CONCLUSION

Both hypermagnesemia and hypomagnesemia are associated with higher risk of coagulopathy in TBI patients. Physicians should pay more attention on preventing coagulopathy in TBI patients with hypomagnesemia or hypermagnesemia.

Blood Products, Crystalloids, and Rapid Infusion: An Experimental Study With Magnesium

OBJECTIVES

Calcium and magnesium are concentration-dependent pro- and anticoagulant cofactors, and magnesium behaves similarly to calcium in the presence of citrate. The authors hypothesized that magnesium can cause clot formation (primary objective) when mixed with coagulation factor-containing blood products diluted with different crystalloids in a rapid- infuser reservoir. A secondary objective was the observation of any infuser alarms and stops in the event of clotting.

DESIGN

An experimental in vitro study with blood products, crystalloids, magnesium, and calcium in a rapid infuser with a reservoir using a closed-loop system.

SETTING

Anesthesia research laboratory at an urban academic tertiary medical center PARTICIPANTS: Not applicable.

INTERVENTIONS

Exposure of fresh frozen plasma (FFP) and packed red blood cells alone (control) or in combination with either normal saline (NS), lactated Ringer's solution (LR), or Plasma-Lyte A (PL) to increasing concentrations of magnesium sulphate (MgSO₄) up to 1 g. After each incremental MgSO₄ change, the authors applied a specific pump-flow sequence in a closed-loop system with a rapid-infuser reservoir, and if no clot was observed, the authors incrementally added calcium chloride (CaCl₂) up to 1 g.

MEASUREMENTS AND MAIN RESULTS

Observation of macroscopic clot and time to event, as well as occurrence and type of any pump alarms or stops. LR experiments resulted in clot observation in the reservoir by a dedicated observer after MgSO₄ 275 ± 206 mg (95% confidence interval [CI], 9-541). Adding MgSO₄ 1 g in the NS, PL, or the control experiments did not result in clot observation. Only when CaCl₂ 166.7 ± 51.64 mg (95% CI, 112.0-22.01) was added to the combination of blood products alone or mixed with NS and PL, clotting occurred. The mean FFP volume was 281 ± 48.6 mL (range, 204-340 mL) and was not different between groups (p = 0.44). Pump alarms and stops were inconsistent.

CONCLUSIONS

The addition of magnesium to a combination of LR with coagulation factor- containing blood products consistently resulted in a visible blood clot in the rapid-infuser reservoir in the authors' experimental setup. In addition to MgSO₄ 1 g in the control, NS, and PL experiments, CaCl₂ is needed before a clot can be observed.

Magnesium and Risk of Bleeding Complications From Ventriculostomy Insertion

BACKGROUND AND PURPOSE

Hemorrhages are a serious complication of brain surgery, and magnesium has shown hemostatic properties in hemorrhagic stroke and non-neurological surgeries. External ventricular drain (EVD) insertion is an advantageous model of emergency neurosurgical hemorrhage risk because it is common, standardized, and the operator is blinded to the outcome during the procedure. We tested the hypothesis that low magnesium is associated with risk of hemorrhagic complications from EVD insertion.

METHODS

Patients with spontaneous intracerebral hemorrhage and aneurysmal subarachnoid hemorrhage were enrolled in a prospective, observational study. Demographic and clinical variables were prospectively recorded, including serum magnesium measurements. Catheter tract hemorrhage (CTH) was measured on postoperative head computed tomography within 48 hours of EVD insertion.

RESULTS

We observed 50 CTH among 327 EVD procedures (15.3%) distributed similarly among intracerebral hemorrhage (21/116 [18.1%]) and subarachnoid hemorrhage (29/211 [13.7%]). Magnesium was lower in patients with CTH compared with those without (median 1.8 versus 2.0 mg/dL, P<0.0001). Higher magnesium was associated with lower odds of CTH (odds ratio 0.67 per 0.1 mg/dL magnesium [95% CI, 0.56-0.78], P<0.0001) after adjustment for other risk factors, with similar effect in the intracerebral hemorrhage and subarachnoid hemorrhage subgroups. Preprocedural increase in magnesium (odds ratio 0.68 [0.52-0.85]) and dose of preprocedural magnesium sulfate (odds ratio 0.67 [0.40-0.97]) were associated with reduced CTH risk after adjustment for initial magnesium and other risk factors.

CONCLUSIONS

Lower magnesium at the time of EVD insertion was an independent predictor of hemorrhagic complications. Baseline risk was attenuated by preprocedural increases in magnesium, suggesting a therapeutic opportunity.

Magnesium Therapy Improves Rotational Thromboelastometry Findings Prior to Liver Transplantation: A Randomized Clinical Trial

An important challenge during orthotopic liver transplantation (OLT) is optimal coagulation management. There are diverse studies regarding effect of Mg sulfate on coagulation system. This study evaluates the impact of Mg sulfate on the coagulation parameters of the rotational thromboelastometry (ROTEM) in patients about to undergo OLT. In this randomized clinical trial, 60 patients who were going to undergo OLT were randomly allocated into two groups. In the Mg group, the patients received a 1.5 g infusion of Mg 5 min before the surgical incision. In the control group, patients received a physiological saline instead of Mg. Plasma Mg levels before and after the infusions were measured in both groups. Also, three ROTEM tests: EXTEM, INTEM and FIBTEM were performed before and after the infusions. Baseline mean plasma magnesium levels were within normal range in the control and Mg groups: 2.06 and 2.18 mg/dl, respectively. After magnesium therapy, the mean plasma Mg level in the Mg group increased to 2.78 mg/dl in compared to the control group that was 2.01 mg/dl (P < 0.000). Mean value of the clotting time (CT) in the magnesium group were significantly decreased from 129.50 ± 7.76, 381.86 ± 8.51 and 114.26 ± 6.80 to 86.13 ± 3.4, 209.33 ± 6.68 and 81.56 ± 5.01 in the EXTEM, INTEM, and FIBTEM respectively after intervention in the Mg group (P = 0.001). Among patients with end-stage liver diseases who have ROTEM evidence of hypocoagulability, magnesium could correct CT parameter of the ROTEM tests.

Magnesium and Hemorrhage Volume in Patients With Aneurysmal Subarachnoid Hemorrhage

OBJECTIVES

We tested the hypothesis that admission serum magnesium levels are associated with extent of hemorrhage in patients with aneurysmal subarachnoid hemorrhage.

DESIGN

Single-center prospective observational study.

SETTING

Tertiary hospital neurologic ICU.

PATIENTS

Patients with aneurysmal subarachnoid hemorrhage.

INTERVENTIONS

Clinically indicated CT scans and serum laboratory studies.

MEASUREMENTS AND MAIN RESULTS

Demographic, clinical, laboratory, and radiographic data were analyzed. Extent of initial hemorrhage was graded semi-quantitatively on admission CT scans using the modified Fisher scale (grades: 0, no radiographic hemorrhage; 1, thin [< 1 mm in depth] subarachnoid hemorrhage; 2, thin subarachnoid hemorrhage with intraventricular hemorrhage; 3, thick [≥ 1 mm] subarachnoid hemorrhage; 4, thick subarachnoid hemorrhage with intraventricular hemorrhage). We used both ordinal (modified Fisher scale) and dichotomized (thick vs thin subarachnoid hemorrhage) univariate and adjusted logistic regression models to assess associations between serum magnesium and radiographic subarachnoid hemorrhage severity. Data from 354 patients (mean age 55 ± 14 yr, 28.5% male, median admission Glasgow Coma Scale 14 [10-15]) were analyzed. Mean magnesium was lower in patients with thick versus thin subarachnoid hemorrhage (1.92 vs 1.99 mg/dL; p = 0.022). A monotonic trend across categories of modified Fisher scale was found using analysis of variance and Spearman rank correlation (p = 0.015 and p = 0.008, respectively). In adjusted ordinal and binary regression models, lower magnesium levels were associated with higher modified Fisher scale (odds ratio 0.33 per 1 mg/dL increase; 95% CI, 0.14-0.77; p = 0.011) and with thick subarachnoid hemorrhage (odds ratio 0.29 per 1 mg/dL increase; 95% CI, 0.10-0.78; p = 0.015).

CONCLUSIONS

These data support the hypothesis that magnesium influences hemorrhage severity in patients with aneurysmal subarachnoid hemorrhage, potentially through a hemostatic mechanism.

Characterization and Hemostatic Potential of Two Kaolins from Southern China

The physicochemical properties and potential hemostatic application of Wenchang kaolin and Maoming kaolin were inspected and evaluated. Chemical composition analysis, Fourier transform infrared (FTIR) spectroscopy, surface area determination, X-ray diffraction, particle size, scanning electron microscopy (SEM) observations, and zeta potential analysis were performed to quantify the physical and chemical properties of the two kaolins. The results showed that both kaolins have typical FTIR bands of kaolinite with a weight fraction for kaolinite over 90 wt%. Larger conglobate aggregates of Maoming kaolin demonstrated wider particle size distributions with two peaks at 3.17 and 35.57 μm, while the book-like Wenchang kaolin had narrow particle size distribution, with a frequent size of 5.64 μm. Furthermore, thrombelastography, the whole blood clotting tests (WBCT), plasma recalcification time (PRT) measurement, and MTT assay were performed to measure the clotting activities and biocompatibility of the two kaolins. The results showed that both kaolins could promote blood coagulation with good cytocompatibility, while Wenchang kaolin had a better procoagulant activity than Maoming kaolin. These findings demonstrated Wenchang kaolin to be a more suitable local source material for application as a hemostatic agent.

Magnesium, hemostasis, and outcomes in patients with intracerebral hemorrhage

OBJECTIVE

We tested the hypothesis that admission serum magnesium levels are associated with hematoma volume, hematoma growth, and functional outcomes in patients with intracerebral hemorrhage (ICH).

METHODS

Patients presenting with spontaneous ICH were enrolled in an observational cohort study that prospectively collected demographic, clinical, laboratory, radiographic, and outcome data. We performed univariate and adjusted multivariate analyses to assess for associations between serum magnesium levels and initial hematoma volume, final hematoma volume, and in-hospital hematoma growth as radiographic measures of hemostasis, and functional outcome measured by the modified Rankin Scale (mRS) at 3 months.

RESULTS

We included 290 patients for analysis. Admission serum magnesium was 2.0 ± 0.3 mg/dL. Lower admission magnesium levels were associated with larger initial hematoma volumes on univariate (p = 0.02), parsimoniously adjusted (p = 0.002), and fully adjusted models (p = 0.006), as well as greater hematoma growth (p = 0.004, p = 0.005, and p = 0.008, respectively) and larger final hematoma volumes (p = 0.02, p = 0.001, and p = 0.002, respectively). Lower admission magnesium level was associated with worse functional outcomes at 3 months (i.e., higher mRS; odds ratio 0.14, 95% confidence interval 0.03-0.64, p = 0.011) after adjustment for age, admission Glasgow Coma Scale score, initial hematoma volume, time from symptom onset to initial CT, and hematoma growth, with evidence that the effect of magnesium is mediated through hematoma growth.

CONCLUSIONS

These data support the hypothesis that magnesium exerts a clinically meaningful influence on hemostasis in patients with ICH.

The effects of magnesium on the course of atrial fibrillation and coagulation in patients with atrial fibrillation undergoing mitral valve annuloplasty

Background

Atrial fibrillation (AF) is the most common cardiac arrhythmia. Magnesium has been reported to be effective in reducing the incidence or prophylaxis of AF. Magnesium is also an essential constituent of many enzyme systems and plays a physiological role in coagulation regulation. The aim of the present study was to examine the effects of magnesium, whether magnesium infusion might decrease the incidence of AF and induce hypocoagulable state in patients with AF, who were undergoing mitral valve annuloplasty.

Methods

This prospective laboratory study was performed using blood from patients with AF undergoing mitral valve annuloplasty. The radial artery was punctured with a 20 gauge catheter and used for monitoring continuous arterial pressure and blood sampling. After anesthesia induction, 4 g of magnesium was mixed with 100 ml normal saline and infused for 5 minutes. Magnesium, calcium, activated clotting time (ACT) and thromboelastographic parameters were checked before and 60 minutes after the magnesium infusion. The electrocardiography changes after magnesium infusion were also checked before commencing cardiopulmonary bypass.

Results

After magnesium infusion, the serum level of magnesium increased significantly but serum calcium did not change significantly. ACT did not change significantly before or after magnesium infusion. The thromboelastographic parameters showed no significant changes before or after magnesium infusion. None of the patients converted to sinus rhythm from AF after the magnesium infusion.

Conclusions

A magnesium infusion did not influence the course of AF and coagulation in patients during prebypass period with AF undergoing mitral valve annuloplasty.

The effects of magnesium pretreatment on reperfusion injury during living donor liver transplantation

Background

Ischemia reperfusion (IR) injury is a complex phenomenon that leads to organ dysfunction and causes primary liver failure following liver transplantation. We investigated whether an intravenous administration of magnesium before reperfusion can prevent or reduce IR injury.

Methods

Fifty-nine living donor liver transplant recipients were randomly assigned to an MG group (n = 31) or an NS group (n = 28). Each group was also divided in two groups based on the preoperative magnesium levels (normal: ≥ 0.70 mmol/L, low: < 0.70 mmol/L). The MG groups received 25 mg/kg of MgSO₄ mixed in 100 ml normal saline intravenously before reperfusion and the NS groups received an equal volume of normal saline. The levels of lactate, pH, arterial oxygen tension, and base excess were measured to assess reperfusion injury at five specific times, which were 10 min after the beginning of anhepatic phase, and 10, 30, 60 and 120 min after reperfusion. To evaluate postoperative organ function, the serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), total bilirubin and creatinine levels were measured at preoperative day 1, postoperative day 1 and 5.

Results

The blood lactate levels were significantly lower at 10, 30, 60 and 120 min after reperfusion in the MG groups compared to the NS groups. In addition, significantly higher blood lactate levels were observed in the NS group with preoperative hypomagnesemia than in MG groups.

Conclusions

Magnesium administration before reperfusion of liver transplantation significantly reduces blood lactate levels. These findings suggest that magnesium treatment may have protective effects on IR injury during living donor liver transplantation.

Effects of combined balanced colloid and crystalloid on rotational thromboelastometry in vitro

Our objective was to investigate the in vitro effects of a totally balanced fluid concept on whole blood coagulation. Venous blood from 12 healthy volunteers was diluted by 20% and 40% with a combination of an equal amount of colloid (balanced or unbalanced 6% HES 130/0.4, or 4% gelatin) and crystalloid (balanced or unbalanced Ringer's acetate). Blood samples were analyzed with rotational thromboelastometry (ROTEM®). The initiation of coagulation was delayed in all dilutions except for the 20 vol% gelatin-dilution. In the extrinsic activation test, maximum clot firmness was decreased and clot formation time prolonged after 40 vol% hemodilution with a balanced Ringer's/unbalanced HES combination, more than in the corresponding gelatin hemodilution. In the fibrin-based test, after both 20- and 40 vol% hemodilution with unbalanced Ringer's/gelatin solution, maximum clot firmness was significantly stronger than in the Ringer's/HES-combinations. The combination of balanced colloid and crystalloid has similar coagulation effects in vitro as their respective combination of unbalanced solutions.

Risk factors and outcome associated with hypomagnesemia in massive transfusion

BACKGROUND

Electrolyte disturbances are common in patients with critical bleeding requiring massive transfusion. The risk factors and outcome associated with the occurrence of hypomagnesemia in massive transfusion remain uncertain.

STUDY DESIGN AND METHODS

A cohort of 353 consecutive patients who required massive transfusion, defined as 10 or more units of allogeneic red blood cells or whole blood transfusion within 24 hours, between 2002 and 2008 in a quaternary health care center in Western Australia was considered. Logistic regression was used to identify risk factors and outcome associated with hypomagnesemia during massive transfusion (<0.7 mmol/L or 1.7 mg/dL).

RESULTS

Of the 353 patients requiring massive transfusion during the study period, 298 patients (84%) had serum magnesium concentrations available for analysis. Hypomagnesemia was common (172 patients, 58%), and the mean magnesium concentration was 0.68 mmol/L (1.65 mg/dL; standard deviation, 0.15 mmol/L) in these patients. The risk factors for hypomagnesemia were hypocalcemia (odds ratio [OR], 1.67 per 0.1 mmol/L decrement; 95% confidence interval [CI], 1.36-2.01; p = 0.001) and hypofibrinogenemia (OR, 1.05 per 0.1 g/L decrement; 95% CI, 1.01-1.09; p = 0.009). The lowest serum magnesium concentrations were associated with the lowest ionized calcium concentrations (Spearman correlation coefficient, 0.377; p = 0.001). Both magnesium concentrations (OR, 0.91 per 0.1 mmol/L increment; 95% CI 0.31-2.69; p = 0.863) and the interaction term between magnesium and calcium concentrations were not associated with an increased risk of mortality after adjusting for other covariates.

CONCLUSIONS

Hypomagnesemia was common and associated with hypocalcemia in massive transfusion, but serum magnesium concentrations had no independent effect or interactive effect with hypocalcemia on mortality of patients requiring massive transfusion.

Current approach to intraoperative monitoring in liver transplantation

PURPOSE OF REVIEW

Although liver transplantation has become a standardized treatment and the only established definite therapy for end-stage liver disease it remains a unique clinical procedure. Increased understanding of the specific pathophysiological changes in end-stage liver disease and the transplantation procedure have led to the adaptation of concepts including overall monitoring of the patient and assessment of specific organ function.

RECENT FINDINGS

Major emphasis is placed on adequate monitoring during perioperative care of liver transplantation patients in order to ensure optimal hemodynamic and respiratory performance. The immediate assessment of metabolism and graft function will also serve to guide therapy according to the individual patient's needs.

SUMMARY

The evolution of monitoring during standardized liver transplantation, as well as currently recommended novel devices and concepts, are described and discussed.

The Coagulation Changes Induced by Rapid In Vivo Crystalloid Infusion Are Attenuated When Magnesium Is Kept at the Upper Limit of Normal

BACKGROUND

Rapid crystalloid infusion enhances coagulation, regardless of electrolytes, pH or osmolality, an effect thought to be related to deep vein thrombosis and other clot formations. Altered serum magnesium may play a role in the balance of coagulation. In this in vivo study we investigated the coagulation response to rapid hemodilution when serum magnesium is maintained or partially increased.

METHODS

Twenty-five healthy volunteers were investigated on three occasions, randomly receiving normal saline, Balsol (magnesium 1.5 g/L), and Balsol plus additional magnesium (magnesium 3.0 g/L). Investigators were blinded to the solution's identity. Baseline blood samples were taken measuring hematocrit, serum magnesium, and thrombelastography (TEG), whereafter 14 mL/kg (20% blood volume) was infused over 30 min, followed by a second blood sample. All results were compared to their own baseline values using ANOVA with LSD post hoc significance testing.

RESULTS

All groups had a similar postdilutional hematocrit decrease, with significant magnesium reduction in the saline group (0.81 +/- 0.07 to 0.74 +/- 0.07 (approximately -8.6%) (P < 0.003)), no change in the Balsol group and significant increase in the Balsol + magnesium group (0.84 +/- 0.07 to 0.99 +/- 0.06 (approximately 17.9%) (P < 0.001)). Postdilutional TEG results reflected no significant change from control in the Balsol + magnesium group. Both of the other two groups had statistically significant increased clot formation (reaction time to onset of clotting and clotting time shortened; alpha-angle increased).

CONCLUSIONS

Rapid hemodilution-induced coagulation may be partially due to decreased magnesium, and the effect is attenuated by maintaining magnesium at the upper limit of normal. Crystalloid resuscitation fluids should possibly contain higher magnesium levels, around 3 mmol/L.