Inpatients pushed into heart failure by excess IV fluids

Hospital inpatients are developing acute decompensated heart failure because of overuse of IV fluids or because their diuretics are stopped, Victorian clinicians have found.

One in a hundred inpatients develop acute decompensated heart failure (ADHF) during their stay and a third of cases are iatrogenic, a four month study of 7678 patients on medical, surgical and oncology wards at Melbourne’s Austin Hospital shows.

The findings are concerning because patients who develop ADHF have double the length of hospital stay (15 vs 6 days) and a dramatically higher mortality rate (13% vs 1%) compared to patients who did not develop the condition, the researchers say.

And while the 1% incidence may appear low, this represents a substantial number of avoidable cases of heart failure with poor outcomes across the hospital system, they argue.

The study, carried out in 2016, identified inappropriately large volumes of IV fluids as the precipitating factor in 24% of the 80 ADHF cases seen on the wards.

Other common causes included infection (30%), tachyarrhythmia (13%), ischaemic heart disease (9%) and inappropriate medication management (9%).

Study author  Dr Luke Plant, of the hospital’s department of emergency medicine, says the patients who developed ADHF had received three times the IV fluid volumes compared to a control cohort of patients who did not develop ADHF.

“Excessive IV fluid volumes may increase pre-load to a level that cannot be accommodated by the heart, with the precipitation of ADHF,” the study authors write.

The blame may lay in fixed IV fluid regimens of 3 L/day that are not tailored to a patient’s individudal circumstances, they suggest.

The high mortality  and extended hospital stays associated with iatrogenic ADHF  suggest a need for more rigorous IV fluid management for inpatients, “including frequent and ongoing review of the patient’s fluid balance and the indications for fluid, its nature and administration rate,” the authors recommend.

Diligent documentation of fluid balance is also needed to avoid ADHF, including daily weighing of patients at increased risk, they add.

Most of the medication-linked cases of ADHF appeared to be related to withholding of a patient’s usual diuretics after hospital admission. While this may be appropriate due to hypotension or hypovolaemia, the medications were not restarted when their condition resolved.

“Mechanisms to remind clinicians that re-adjustment of the medications may be needed upon resolution of the illness. These mechanisms may involve the ward pharmacy service or automatic flagging embedded within the electronic medical record,” they suggest.

The findings are published in Heart Lung and Circulation.

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