Hypomagnesemia in trauma patients

Trauma-induced hypocalcemia

BACKGROUND

Trauma-induced hypocalcemia is an underappreciated complication of severe injury but is well known to result in the derangement of an array of physiological regulatory mechanisms. Existing literature provides a compelling link between hypocalcemia and worse trauma-induced coagulopathy and increased mortality after injury.

STUDY DESIGN AND METHODS

This narrative review evaluates available data related to the risk factors, mechanisms, and treatment of hypocalcemia after severe injury. The authors did not perform a systemic review or meta-analysis.

RESULTS AND DISCUSSION

The interplay of acidosis, hypothermia, and coagulopathy with hypocalcemia potentiates the bloody vicious cycle of hemorrhagic shock which has been the paradigm of trauma resuscitation for over half a century. However, current screening and treatment of postinjury hypocalcemia are relegated to a secondary consideration in trauma resuscitation. We conclude calcium supplementation should be a primary tier intervention for life-threatening injury.

Association between ion shift index and prognosis in severe trauma patients without isolated head injury

INTRODUCTION

This study aimed to investigate the ion shift index (ISI) as a prognostic factor of severe trauma. We hypothesized that the initial ISI measured in the emergency department (ED) is associated with discharge survival in severe non-isolated head injury (IHI) patients.

MATERIALS AND METHODS

This retrospective observational study included severe trauma patients with available medical records from January 2017 to December 2018 but excluded those with IHI. Logistic regression analysis was conducted to identify the risk factors for mortality in non-IHI patients, and adjustments were performed for relevant covariates. An area under the receiver operating characteristics curve (AUROC) analysis was performed to examine the primary outcome of our study, which was mortality at hospital discharge in severe non-IHI trauma patients.

RESULTS

Of the 483 severe non-IHI trauma patients included in the study, 86 patients (17.8 %) died. The multiple logistic regression analysis demonstrated ISI (odds ratio [OR], 2.300; 95% CI, 1.183-4.470) was significantly associated with mortality in the non-IHI group. Additionally, trauma and injury severity score (TRISS; OR, 0.538; 95% CI, 0.447-0.649), lactate (OR, 1.410; 95% CI, 1.252-1.588), creatinine (OR, 1.554; 95% CI, 1.221-1.979), and activated partial thromboplastin time (aPTT; OR, 1.050; 95% CI, 1.021-1.080) were independently associated with mortality at hospital discharge. The AUROC values for TRISS, lactate, aPTT, creatinine, and ISI were as follows: 0.892 (95% CI, 0.861-0.918), 0.838 (95% CI, 0.803-0.870), 0.754 (95% CI, 0.712-0.792), 0.650 (95% CI, 0.606-0.693), and 0.848 (95% CI, 0.813-0.879), respectively. The AUROC for the multiple logistic regression model with ISI was 0.942 (95% CI, 0.917-0.962). In a model in which TRISS was omitted, the addition of ISI to other predictors significantly improved the AUROC to 0.900 (95% CI, 0.869-0.925) (p=0.039).

CONCLUSION

The initial ISI in the ED after trauma was associated with mortality in severe non-IHI trauma patients. In conjunction with other prognostic indicators, it could be used as an early prognostic marker, particularly if TRISS is unavailable.

Review of the refeeding syndrome

Refeeding syndrome describes a constellation of metabolic disturbances that occur as a result of reinstitution of nutrition to patients who are starved or severely malnourished. Patients can develop fluid and electrolyte disorders, especially hypophosphatemia, along with neurologic, pulmonary, cardiac, neuromuscular, and hematologic complications. We reviewed literature on refeeding syndrome and the associated electrolyte abnormalities, fluid disturbances, and associated complications. In addition to assessing scientific literature, we also considered clinical experience and judgment in developing recommendations for prevention and treatment of refeeding syndrome. The most important steps are to identify patients at risk for developing refeeding syndrome, institute nutrition support cautiously, and correct and supplement electrolyte and vitamin deficiencies to avoid refeeding syndrome. We provide suggestions for the prevention of refeeding syndrome and suggestions for treatment of electrolyte disturbances and complications in patients who develop refeeding syndrome, according to evidence in the literature, the pathophysiology of refeeding syndrome, and clinical experience and judgment.

Treatment of electrolyte disorders in adult patients in the intensive care unit

PURPOSE

The treatment of electrolyte disorders in adult patients in the intensive care unit (ICU), including guidelines for correcting specific electrolyte disorders, is reviewed.

SUMMARY

Electrolytes are involved in many metabolic and homeostatic functions. Electrolyte disorders are common in adult patients in the ICU and have been associated with increased morbidity and mortality, as has the improper treatment of electrolyte disorders. A limited number of prospective, randomized, controlled studies have been conducted evaluating the optimal treatment of electrolyte disorders. Recommendations for treatment of electrolyte disorders in adult patients in the ICU are provided based on these studies, as well as case reports, expert opinion, and clinical experience. The etiologies of and treatments for hyponatremia hypotonic and hypernatremia (hypovolemic, isovolemic, and hypervolemic), hypokalemia and hyperkalemia, hypophosphatemia and hyperphosphatemia, hypocalcemia and hypercalcemia, and hypomagnesemia and hypermagnesemia are discussed, and equations for determining the proper dosages for adult patients in the ICU are provided. Treatment is often empirical, based on published literature, expert recommendations, and the patient's response to the initial treatment. Actual electrolyte correction requires individual adjustment based on the patient's clinical condition and response to therapy. Clinicians should be knowledgeable about electrolyte homeostasis and the underlying pathophysiology of electrolyte disorders in order to provide the optimal therapy to patients.

CONCLUSION

Treatment of electrolyte disorders is often empirical, based on published literature, expert opinion and recommendations, and patient's response to the initial treatment. Clinicians should be knowledgeable about electrolyte homeostasis and the underlying pathophysiology of electrolyte disorders to provide optimal therapy for patients.

Do intracellular, extracellular or urinary magnesium concentrations predict renal retention of magnesium in critically ill patients?

BACKGROUND AND OBJECTIVE

Magnesium disorders are common in hospitalized patients. In patients with low or normal magnesium, the intravenous magnesium loading test has been demonstrated to be a sensitive test to assess magnesium deficiency in critically ill patients. However, it is more time consuming and more difficult than the measurement of intracellular or extracellular magnesium concentrations. This study evaluated whether erythrocyte, plasma and urinary magnesium concentrations predict renal magnesium retention measured by th magnesium loading test.

METHODS

One-hundred-and-three intensive care patients (36 females, 67 males) in a tertiary care centre and 41 healthy subjects (13 females, 28 males) took part in this prospective study. Intracellular, total plasma, ionize extracellular and urinary magnesium concentrations were measured and also magnesium retention by intravenous magnesium loading test.

RESULTS

Total plasma magnesium concentration was poorly correlated with magnesium retention (r = 0.36 r2 = 0.13) and was the only parameter that significantly predicted magnesium retention in intensive care patients (P < 0.01). However, only 10% of the magnesium retention data were linked to the total plasma magnesium concentration.

CONCLUSIONS

Total plasma magnesium concentration predicts magnesium retention in critically ill intensive care patients but not intracellular and urinary magnesium concentrations. Only a small proportion of the magnesium retention was due to the total plasma magnesium concentration.

Hypomagnesemia after Major Abdominal Operations in Cancer Patients: Clinical Implications

BACKGROUND

Serum magnesium levels are rarely measured in routine chemistry panels. The extent and impact of postoperative serum magnesium changes remain unclear.

METHODS

One hundred seventy-one cancer patients who had undergone celiotomy procedures during a 38-month period were evaluated retrospectively for postoperative electrolyte alterations, with special emphasis on serum magnesium. Clinicopathologic predictors and early postoperative outcome correlations were examined.

RESULTS

There were 151 major procedures and 20 minor operations. All postoperative electrolyte and hematocrit values were significantly different from preoperative values, except for serum phosphate. Preoperative total serum magnesium (normal range: 1.7-2.5 mg/dL {0.7-1.03 mmol/L}), obtained prior to any bowel cleansing, differed from postoperative levels (means +/- standard deviation: 2.0 +/- 0.46 vs. 1.53 +/- 0.33 mg/dL; p < 0.0001). A lowered postoperative serum magnesium was observed in those patients who had either undergone an operation with curative intent (p = 0.0035), a major resection (vs. no resection, p = 0.0259), or preoperative bowel cleansing with sodium phosphate (p = 0.024). Other laboratory serum parameters that correlated with the postoperative magnesium level included postoperative levels of phosphate (p = 0.009), potassium (p = 0.01), and total calcium (p = 0.012), as well as preoperative calcium (p = 0.017). The complication rate was 20%, with five postoperative deaths (2.9%). Postoperative morbidity was predicted by preoperative potassium (p = 0.004) and albumin levels (p = 0.016); deaths were predicted by postoperative infections (p = 0.0007) and correlated to postoperative hypokalemia (p = 0.03).

CONCLUSIONS

Major abdominal cancer operations lead to significant electrolyte alterations. The severity of these changes correlates with the resection extent, especially in procedures with curative intent. In addition, bowel cleansing with sodium phosphate may participate in lowering serum magnesium as well as other electrolytes. In light of our postoperative magnesium replacement policy, no untoward events could be linked to postoperative hypomagnesemia in this series. To evaluate the impact of postoperative hypomagnesemia or magnesium replacement on postoperative outcomes requires a prospective randomized trial.

Hypomagnesemia in Hospitalized Horses

This study was initiated to identify the signalment and clinical variables potentially associated with hypomagnesemia in horses evaluated at the North Carolina State University, College of Veterinary Medicine (NCSU-CVM) veterinary teaching hospital between January 1999 and May 2001. A nested case reference study (nested case-control study) was conducted to examine the potential relationship between hypomagnesemia and signalment, serum chemistry panel analyses, number of hospitalization days, discharge status, and diagnosis. A series of independent and multivariable logistic regression models were used to assess the potential association of each variable with low total serum magnesium concentrations. Four hundred one of 823 (48.7%) horses had serum total magnesium concentrations below the normal reference range. Hypomagnesemia was more likely to occur in horses older than I month of age. Colic (odds ratio [OR]: 2.96, 95% confidence intervals [CI]: 2.14-4.08), acute diarrhea (OR: 5.91, 95% CI: 2.32-15.06), other gastrointestinal disease (OR: 2.07, 95% CI: 1.15-3.71), infectious respiratory disease (OR: 5.07, 95% CI: 2.09-12.28), and multiorgan system disease (OR: 2.31, 95% CI: 1.24-4.28) were associated with hypomagnesemia in adult horses, whereas foals with diarrhea (excluding septic foals) (OR: 0.11, 95% CI: 0.01-0.84) were less likely to have hypomagnesemia. Overall, there was no relationship between hypomagnesemia and mortality (OR: 1.00, 95% CI: 0.72-1.41), but horses with colic and hypomagnesemia were less likely to die than horses with colic and normal or high total magnesium (OR: 0.53, 95% CI: 0.30-0.95). Among horses that survived, hypomagnesemia at admission was associated with a longer hospitalization period (OR: 1.45, 95% CI: 1.00-2.11).

Development of ionized hypomagnesemia is associated with higher mortality rates

OBJECTIVE

Previous studies have shown a wide variation in the prevalence of total serum hypomagnesemia in intensive are unit (ICU) patients and in associated mortality rates. As the ionized part of magnesium is the active portion, we sought to define the prevalence of ionized hypomagnesemia in critically ill patients and to evaluate its relationship with organ dysfunction, length of stay, and mortality.

DESIGN

Prospective observational study.

SETTING

A 31-bed, medical-surgical, university hospital ICU.

PATIENTS

A total of 446 consecutive patients admitted to the ICU over a 3-month period.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The ionized magnesium level (normal value, 0.42-0.59 mmol/L) was measured at admission and then every day until discharge from the ICU. At admission, 18% of patients had ionized hypomagnesemia, 68% had normal ionized magnesium levels, and 14% had ionized hypermagnesemia. There was no significant difference in the length of stay or in the mortality rate between these three groups of patients. Hypomagnesemic patients more frequently had total and ionized hypocalcemia, hypokalemia, and hypoproteinemia. A total of 23 patients developed ionized hypomagnesemia during their ICU stay; these patients had higher Acute Physiology And Chronic Health Evaluation II (14.9 +/- 5.4 vs. 11.0 +/- 6.2) and Sequential Organ Failure Assessment (SOFA; 7.1 +/- 5.4 vs. 3.9 +/- 2.8) scores at admission (p <.01 for both), a higher maximum SOFA score during their ICU stay (10.0 +/- 5.6 vs. 4.4 +/- 3.2, p <.01), a higher prevalence of severe sepsis and septic shock (57 vs. 11%, p <.01), a longer ICU stay (15.4 +/- 15.5 vs. 2.8 +/- 4.7 days, p <.01), and a higher mortality rate (35% vs. 12%, p <.01) than the other patients. The major risk factors for developing hypomagnesemia during the ICU stay were a prolonged ICU stay, treatment with diuretics, and sepsis.

CONCLUSION

Development of ionized hypomagnesemia during an ICU stay is associated with a worse prognosis. It is often associated with the use of diuretics and the development of sepsis. Monitoring of ionized magnesium levels may have prognostic, and perhaps therapeutic, implications.