B-type or Brain Natiuretic Peptide (BNP) is secreted by the heart ventricles in response to excessive stretching of the heart. It’s physiologic actions is to decrease vascular resistance and increase natiuresis, thereby off-loading the strained heart ventricle. Recently BNP is finding more and more applications as a marker of fluid overload in critical care. A study in Am J Respir Crit Care Med demonstrates how BNP can be used to shorten ventilator weaning times.
This study looks at how BNP can help us wean ICU patients from their ventilator. This is important as at least 40% of the total time on a ventilator are spent weaning the patient. If the time weaning takes can be reduced there is an enormous gain in reduced costs, reduced resources and less complications like ventilator associated pneumonia and diaphragmal atrophy.
A most common reason for weaning failure is fluid overload and cardiac failure resulting in weaning failure. This can be countered by maintaining a minimised positive fluid balance. This is where BNP fits in. In this study 304 patients ready for weaning were randomised into either the BNP group or the traditional group.
In the BNP group elevated BNP levels > 200 pg/ml (fluid overload) triggered fluid restriction and furosemide boluses were given to increase urine output. This BNP group was compared to a control group with traditional weaning tactics and usual fluid management.
The curves on the right display the probability of a successful extubation during 60 days after randomisation.
In the BNP group, weaning time was significantly shorter. Mean 42,4 h versus 58,6 h. However, ICU stay length and mortality was not affected by the BNP protocol and remained the same.
Study lives here:
Am J Respir Crit Care Med. 2012 Dec 15;186(12):1256-63. doi: 10.1164/rccm.201205-0939OC. Epub 2012 Sep 20. Natriuretic peptide-driven fluid management during ventilator weaning: a randomized controlled trial. Mekontso Dessap A, Roche-Campo F, Kouatchet A, Tomicic V, Beduneau G, Sonneville R, Cabello B, Jaber S, Azoulay E, Castanares-Zapatero D,Devaquet J, Lellouche F, Katsahian S, Brochard L.