Long-term changes in dysnatremia incidence in the ICU: a shift from hyponatremia to hypernatremia

Background: Dysnatremia is associated with adverse outcome in critically ill patients. Changes in patients or treatment strategies may have affected the incidence of dysnatremia over time. We investigated long-term changes in the incidence of dysnatremia and analyzed its association with mortality. Methods: Over a 21-year period (1992–2012), all serum sodium measurements were analyzed retrospectively in two university hospital ICUs, up to day 28 of ICU admission for the presence of dysnatremia. The study period was divided into five periods. All serum sodium measurements were collected from the electronic databases of both ICUs. Serum sodium was measured at the clinical chemistry departments using standard methods. All sodium measurements were categorized in the following categories: 160 mmol/L. Mortality was determined at 90 days after ICU admission. Results: In 80,571 ICU patients, 913,272 serum sodium measurements were analyzed. A striking shift in the pattern of ICU-acquired dysnatremias was observed: The incidence of hyponatremia almost halved (47–25 %, p  155 mmol/L) increased dramatically over the years. On ICU day 10 this incidence was 0.7 % in the 1992–1996 period, compared to 6.3 % in the 2009–2012 period (p < 0.001). More severe dysnatremia was associated with significantly higher mortality throughout the 21-year study period (p < 0.001). Conclusions: In two large Dutch cohorts, we observed a marked shift in the incidence of dysnatremia from hyponatremia to hypernatremia over two decades. As hypernatremia was mostly ICU acquired, this strongly suggests changes in treatment as underlying causes. This shift may be related to the increased use of sodium-containing infusions, diuretics, and hydrocortisone. As ICU-acquired hypernatremia is largely iatrogenic, it should be—to an important extent—preventable, and its incidence may be considered as an indicator of quality of care. Strategies to prevent hypernatremia deserve more emphasis; therefore, we recommend that further study should be focused on interventions to prevent the occurrence of dysnatremias during ICU stay

A Pilot, Double-Blind, Randomized, Controlled Trial of High-Dose Intravenous Vitamin C for Vasoplegia After Cardiac Surgery

OBJECTIVE: To conduct a pilot feasibility and physiologic efficacy study of high-dose vitamin C in patients with vasoplegia after cardiac surgery. DESIGN: Prospective, double-blind, randomized, controlled trial. SETTING: Two tertiary intensive care units (ICUs). PARTICIPANTS: Post-cardiac surgery patients with vasoplegia. INTERVENTIONS: The authors randomly assigned the patients to receive either high-dose intravenous vitamin C (1,500 mg every 6 hours) or placebo. The primary outcome was time from randomization to resolution of vasoplegia. Secondary outcomes included total norepinephrine equivalent dose in the first 2 days, ICU length of stay, ICU mortality, and in-hospital mortality. MEASUREMENTS AND MAIN RESULTS: The authors studied 50 patients (25 patients in each arms). The mean (standard deviation) time to resolution of vasoplegia was 27.0 (16.5) hours in the vitamin C group versus 34.7 (41.1) hours in the placebo group (mean decrease with vitamin C of 7.7 hours, 95% confidence interval -10.5 to 25.9, p = 0.40). The median (interquartile range) norepinephrine equivalent dose in the first 2 days was 64.9 (23.5-236.5) µg/kg versus 47.4 (21.4-265.9) µg/kg in the vitamin C and placebo group (p = 0.75). The median duration of ICU admission was similar (1.4 [0.5-2.5] days and 1.5 [0.5-3.3] days in the vitamin C and placebo group; p = 0.36). Only 1 patient, in the vitamin C arm, died. CONCLUSION: In patients with post-cardiac surgery vasoplegia, high-dose vitamin C infusion was feasible, appeared safe, and, within the limitations of a pilot study, did not achieve statistically faster resolution of vasoplegia

Continuous Magnesium Infusion to Prevent Atrial Fibrillation After Cardiac Surgery: A Sequential Matched Case-Controlled Pilot Study.

OBJECTIVE The authors aimed to test whether a bolus of magnesium followed by continuous intravenous infusion might prevent the development of atrial fibrillation (AF) after cardiac surgery. DESIGN Sequential, matched, case-controlled pilot study. SETTING Tertiary university hospital. PARTICIPANTS Matched cohort of 99 patients before and intervention cohort of 99 consecutive patients after the introduction of a continuous magnesium infusion protocol. INTERVENTIONS The magnesium infusion protocol consisted of a 10 mmol loading dose of magnesium sulphate followed by a continuous infusion of 3 mmol/h over a maximum duration of 96 hours or until intensive care unit discharge. MEASUREMENTS AND MAIN RESULTS The study groups were balanced except for a lower cardiac index in the intervention cohort. The mean duration of magnesium infusion was 27.93 hours (95% confidence interval [CI]: 24.10-31.76 hours). The intervention group had greater serum peak magnesium levels: 1.72 mmol/L ± 0.34 on day 1, 1.32 ± 0.36 on day 2 versus 1.01 ± 1.14 and 0.97 ± 0.13, respectively, in the control group (p < 0.01). Atrial fibrillation occurred in 25 patients (25.3%) in the intervention group and 40 patients (40.4%) in the control group (odds ratio 0.49, 95% CI, 0.27-0.92; p = 0.023). On a multivariate Cox proportional hazards model, the hazard ratio for the development of AF was significantly less in the intervention group (hazard ratio 0.45, 95% CI, 0.26-0.77; p = 0.004). CONCLUSION The magnesium delivery strategy was associated with a decreased incidence of postoperative AF in cardiac surgery patients. These findings provide a rationale and preliminary data for the design of future randomized controlled trials