Loop Diuretics in Acute Oliguric and Pre-renal States

Oliguria is common in critically ill patients, the most common cause being a reduction of the effective intravascular volume. Oliguric patients are almost universally treated with escalating doses of loop diuretics in the hope of increasing urine output. However, in the setting of a reduced effective intravascular volume loop diuretics cause a marked fall in glomerular filtration rate with an acute decline in renal function. In this paper we demonstrate that there is no scientific rationale or clinical evidence to support the use of loop diuretics in patients with oliguria and pre-renal azotemia, prophylactically in patients at risk of developing acute renal failure and in patients with established acute renal failure.


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Henderson-Hasselbalch vs Stewart: Another Acid-Base Controversy

The Henderson-Hasselbalch approach to acid-base physiology and disorders has been the dominant approach for the last 100 years. Over the last 20 years there has been considerable interest in a different approach developed by Peter Stewart. At the center of the controversy around the Stewart approach is replacing the role of bicarbonate with the strong-ion-difference and total weak-acid concentration.The Stewart approach, however, appears to better describe the nature and complexity of the clinical acid-base disorders of the critically ill. The old and the new maybe partially reconciled by combining Stewart’s approach with base-excess. This combination appears to have considerable clinical utility.


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Assessement of Change in Body Water By Multiple Frequency Bioelectrical Impedance in Patients Undergoing Cardiopulmonary Bypass

Objective: To evaluate the relationship between changes in body bioelectrical impedance (BI) at 1, 50, 100 kHz and fluid balance, as an index of body water changes, in patients undergoing cardiopulmonary bypass.
Design: Descriptive, correlative.
Setting: Intensive Care Unit of a cardiac center Patients: Twenty male patients, before and after elective coronary artery bypass graft surgery with cardiopulmonary bypass.
Interventions: None.
Measurements: Whole body bioelectrical impedance using multiple frequency bioelectrical impedance (Dietosystem, Italy) at multiple frequencies (1, 50, 100 kHz) was conducted preoperatively and three times during the 24 hour postoperative period. The volume of body water compartment was calculated using Guricci’s formula. The calculated fluid balances uncorrected for insensible water losses were measured from fluid intake and output.
Findings: In 24 hours after surgery calculated total body water (TBW), extracellular water (ECW), and intracellular water (ICW) increased by 16.0%, 20.7%, and 13.0%, respectively, but the values were within desirable ranges. There was no correlation between TBW changes measured by MFBIA and calculated fluid balance.
Conclusions: The current study indicates that changes of body water compartment occur during 24 hours after CABG. Calculated ICW increases within 24 hours after CABG.


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