Annemieke Oude Lansink

Determinants of renal potassium excretion in critically ill patients : The role of insulin therapy

Objectives:Insulin administration lowers plasma potassium concentration by augmenting intracellular uptake of potassium. The effect of insulin administration on renal potassium excretion is unclear. Some studies suggest that insulin has an antikaliuretic effect although plasma potassium levels were poorly controlled. Since the introduction of glycemic control in the intensive care unit, insulin use has increased. We examined the relation between administered insulin and renal potassium excretion in critically ill patients under computer-assisted glucose and potassium regulation. Design:Prospective observational study. Setting:Twelve-bed surgical intensive care unit of a university teaching hospital. Patients:Consecutive intensive care unit patients. Interventions:Potassium and glucose levels were regulated by a computer-assisted decision support system. Both potassium and insulin were continuously administered by syringe pump. Measurements and Main Results:Renal potassium excretion was measured daily in the 24-hr urine collections. The 24-hr urinary samples of patients with kidney failure or on renal replacement therapy were excluded. Multivariate analysis with potassium excretion as the dependent variable was performed. In 178 consecutive patients, 1,456 24-hr urinary samples, were analyzed. Mean ± SD plasma potassium was 4.2 ± 0.3 mmol/L, with 79 ± 46 mmol/d of potassium administered and a mean insulin dose of 53 ± 38 U/day. Renal potassium excretion was 126 ± 51 mmol/day. After multivariate analysis correcting for relevant variables (including diuretics, pH, potassium levels and renal sodium excretion), insulin administration was independently and positively associated with renal potassium excretion. Other significant variables were potassium levels, potassium administration, renal sodium and chloride excretion, creatinine clearance, diuretic therapy, pH, known diabetes and intensive care unit admission day (R2 = .52; p <. 001). Conclusion:Insulin administration is associated with an increase in the renal potassium excretion in critically ill patients.

Postoperative fluid retention after heart surgery is accompanied by a strongly positive sodium balance and a negative potassium balance

The conventional model on the distribution of electrolyte infusions states that water will distribute proportionally over both the intracellular (ICV) and extracellular (ECV) volumes, while potassium homes to the ICV and sodium to the ECV. Therefore, total body potassium is the most accurate measure of ICV and thus potassium balances can be used to quantify changes in ICV. In cardiothoracic patients admitted to the ICU we performed complementary balance studies to measure changes in ICV and ECV. In 39 patients, fluid, sodium, potassium, and electrolyte‐free water (EFW) balances were determined to detect changes in ICV and ECV. Cumulatively over 4 days, these patients received a mean ± SE infusion of 14.0 ± 0.6 L containing 1465 ± 79 mmol sodium, 196 ± 11 mmol potassium and 2.1 ± 0.1 L EFW. This resulted in strongly positive fluid (4.0 ± 0.6 L) and sodium (814 ± 75 mmol) balances but in negative potassium (−101 ± 14 mmol) and EFW (−1.1 ± 0.2 L) balances. We subsequently compared potassium balances (528 patients) and fluid balances (117 patients) between patients who were assigned to either a 4.0 or 4.5 mmol/L blood potassium target. Although fluid balances were similar in both groups, the additionally administered potassium (76 ± 23 mmol) in the higher target group was fully excreted by the kidneys (70 ± 23 mmol). These findings indicate that even in the context of rapid and profound volume expansion neither water nor potassium moves into the ICV.

Bedside lung ultrasound in the critically ill patient with pulmonary pathology: different diagnoses with comparable chest X-ray opacification

The differential diagnosis and treatment of opacifications on the chest X-ray in critically ill patients may be challenging. This holds in particular the patient that suffers from respiratory failure with hemodynamic instability. Opacification in the chest X-ray could be the result of hematothorax, pleural effusion, atelectasis, or consolidation. Physical examination of such patients may not always indicate what the cause of the opacification is and thus may not always help indicate the correct therapeutic approach. In such cases, bedside ultrasound may be very helpful. We present two cases with similar chest X-ray opacifications but different diagnoses established with the help of a bedside lung ultrasound. There is documented accuracy of ultrasound in differentiating pleural effusions from consolidation. Ultrasound is safe and may be an alternative for computed tomography scan in a hemodynamically or respiratory unstable intensive care patient.

Metabolic and neurologic sequelae in a patient with long-standing anorexia nervosa who presented with septic shock and deep hypoglycemia

OBJECTIVE To report the case of a 48-year female with chronic remitting anorexia nervosa who was found comatose at home and admitted to our hospital with a deep hypoglycemia (glucose level 0.6 mmol/L; 11 mg/dL) and septic shock secondary to a bilateral pneumonia. METHOD Case report. RESULTS After admission to the critical care unit, she further displayed a number of pronounced complications known to be associated with anorexia, including hypophosphatemia, disturbed liver functions and depression of all three hematological cell lines. The neurological recovery of the patient was complicated by encephalopathy and transient tetraparesis. With initial deep hypoglycemia at presentation and persisting coma, magnetic resonance imaging performed 5 days later did not demonstrate characteristic post-hypoglycemic abnormalities. Neuroradiological examination did however reveal the presence of extensive calcifications in the basal ganglia known as Fahrs syndrome. DISCUSSION The potential relation between anorexia nervosa and Fahr syndrome has not been described before. The fact that this patient survived a glucose level that is usually associated with a very poor outcome is probably related to its special origin.

Risk of severe hypernatremia depends on underlying cause in critically ill patients

Excessive free water losses From gastrointestinal tract 10 2 (20%) Resulting from high or persisting fever 6 5 (83%) Renal concentrating defect Central diabetes insipidus 61 48 (79%) Nephrogenic diabetes insipidus 3 1 (33%) Loop diuretics 45 21 (47%) Tubular dysfunction 13 2 (15%) Osmotic diuresis (hyperglycemia, mannitol) 44 30 (68%) Risk of severe hypernatremia depends on underlying cause in critically ill patients

Computer-guided normal-low versus normal-high potassium control after cardiac surgery: No impact on atrial fibrillation or atrial flutter.

INTRODUCTION This study was designed to determine the effect of 2 different potassium regulation strategies with different targets (within the reference range) on atrial fibrillation (AF) or atrial flutter (AFL) in a cohort of intensive care unit patients after cardiac surgery. METHODS The GRIP-COMPASS study was a prospective double-blinded interventional study in 910 patients after cardiac surgery (coronary artery bypass grafting and/or valvular surgery). Patients were assigned to either the normal-low potassium target (nLP group, 4.0 mmol/L) or the normal-high potassium target (nHP group, 4.5 mmol/L) in alternating blocks of 50 patients. Potassium levels were regulated using a validated computer-assisted potassium replacement protocol (GRIP-II). The primary end point was the incidence of AF/AFL on a 12-lead electrocardiogram during the first postoperative week. RESULTS Of the 910 patients, 447 were assigned to the nLP group; and 463, to the nHP group, with no baseline differences between the 2 groups. The mean daily administered dose of potassium was 30 ± 23 mmol (nLP) versus 52 ± 27 mmol (nHP) (P < .001), which resulted in mean intensive care unit potassium concentration of 4.22 ± 0.36 mmol/L and 4.33 ± 0.34 mmol/L, respectively (P < .001). The incidence of AF/AFL after cardiac surgery did not differ: 38% in the nLP group and 41% in the nHP group. Also in several subgroups (eg, patients not known with prior AF/AFL or with valve surgery), there were no differences. CONCLUSIONS There were no differences in incidence of AF/AFL with 2 potassium regulation strategies with different potassium targets and different amounts of potassium administered in patients after cardiac surgery.