To study the effect of preoperative hyponatremia (Na <135 mEq/L) on outcomes after cardiac surgery.
From 2002 to 2008, 4370 patients had cardiac surgery at our institution (CABG in 2238, valve in 597, CABG valve in 537, other in 998). The institution electronic medical records, STS database, and Social Security death index data were analyzed. The association of hyponatremia with mortality, hospital length of stay (LOS), and complications was analyzed using regression analysis.
Prevalence of hyponatremia was 21%. Patients with preoperative hyponatremia had lower left ventricular ejection fraction (39% ± 17% versus 46% ± 14%, P < 0.001) and glomerular filtration rate (69 ± 32 mg/min/1.73 m(2)versus 74 ± 27 mg/min/1.73 m(2), P < 0.001) and higher median EuroSCORE (19% versus 9%, P < 0.001), NYHA class 3-4 (77% versus 65%, P < 0.001), prevalence of chronic obstructive pulmonary disease (25% versus 18%, P < 0.001), and arteriopathy (20% versus 13%, P < 0.001). Hyponatremia was associated with increased early mortality (9% versus 4%, P < 0.001), late mortality (24% versus 16%, P < 0.001), and LOS (13 versus 8 d, P < 0.001). Mortality increased with the severity of hyponatremia. After adjusting for baseline and operative variables, hyponatremia was associated with increased hazard of mortality (hazard ratio [HR] 1.31, 95% confidence interval [CI] 1.14-1.52, P < 0.001), risk of early mortality (odds ratio [OR] 1.52, 95% CI 1.09-2.12, P < 0.001), late mortality (HR 1.37, 95% CI 1.16-1.62, P < 0.001), LOS (multiplier 1.26, 95% CI 1.15-1.39, P < 0.001), operative complications (OR 1.30, 95% CI 1.00-1.69, P = 0.051), and dialysis (OR 1.64, 95% CI 1.11-2.44, P = 0.013).
Preoperative hyponatremia is common, especially in high-risk patients. It is an independent risk factor for mortality, prolonged hospitalization, and complications after cardiac surgery.
[Show abstract][Hide abstract] ABSTRACT: Hyponatraemia-the most common serum electrolyte disorder-has also emerged as an important marker of the severity and prognosis of important diseases such as heart failure and cirrhosis. Acute hyponatraemia can cause severe encephalopathy, but the rapid correction of chronic hyponatraemia can also profoundly impair brain function and even cause death. With the expanding elderly population and the increased prevalence of hyponatraemia in this segment of society, prospective studies are needed to examine whether correcting hyponatraemia in the elderly will diminish cognitive impairment, improve balance and reduce the incidence of falls and fractures. Given that polypharmacy is also common in the elderly population, the various medications that may stimulate arginine vasopressin release and/or enhance the hormone's action to increase water absorption must also be taken into consideration. Whether hyponatraemia in a patient with cancer is merely a marker of poor prognosis or whether its presence may alter the patient's quality of life remains to be examined. In any case, hyponatraemia can no longer be considered as just a biochemical bystander in the ill patient. A systematic diagnostic approach is necessary to determine the specific aetiology of a patient's hyponatraemia. Therapy must then be dictated not only by recognized reversible causes such as advanced hypothyroidism, adrenal insufficiency, diuretics or other medicines, but also by whether the hyponatraemia occurred acutely or chronically. Information is emerging that the vast majority of cases of hyponatraemia are caused by the nonosmotic release of arginine vasopressin. Now that vasopressin V2-receptor blockers are available, a new era of clinical investigation is necessary to examine whether hyponatraemia is just a marker of severe disease or whether correction of hyponatraemia could improve a patient's quality of life. Such an approach must involve prospective randomized studies in different groups of patients with hyponatraemia, including those with advanced heart failure, those with cirrhosis, patients with cancer, and the elderly.
[Show abstract][Hide abstract] ABSTRACT: Hyponatremia and hypernatremia are common findings in the inpatient and outpatient settings. Sodium disorders are associated with an increased risk of morbidity and mortality. Plasma osmolality plays a critical role in the pathophysiology and treatment of sodium disorders. Hyponatremia and hypernatremia are classified based on volume status (hypovolemia, euvolemia, and hypervolemia). Sodium disorders are diagnosed by findings from the history, physical examination, laboratory studies, and evaluation of volume status. Treatment is based on symptoms and underlying causes. In general, hyponatremia is treated with fluid restriction (in the setting of euvolemia), isotonic saline (in hypovolemia), and diuresis (in hypervolemia). A combination of these therapies may be needed based on the presentation. Hypertonic saline is used to treat severe symptomatic hyponatremia. Medications such as vaptans may have a role in the treatment of euvolemic and hypervolemic hyponatremia. The treatment of hypernatremia involves correcting the underlying cause and correcting the free water deficit.
American family physician 03/2015; 91(5):299-307. · 2.18 Impact Factor
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