Plasma BNP increased over 5-fold during therapeutic hypothermia in 21 post-cardiac arrest patients, without corresponding heart failure worsening.
>5-fold BNP riseduring therapeutic hypothermia without heart failure worsening — clinicians should not misinterpret elevated BNP during cooling
What the researchers found
Plasma BNP levels increased more than fivefold during therapeutic hypothermia (logarithmically from 1.98 to 2.63, P < 0.01). This was a highly significant change observed across the 21 patients.
During cooling, diastolic pulmonary artery pressure actually decreased, and stroke volume index did not change significantly. This means the BNP increase was not driven by the usual triggers of cardiac stress or fluid overload.
In contrast to BNP, ANP (atrial natriuretic peptide) showed minimal change during cooling. This selective BNP response suggests a specific mechanism linking cold exposure to BNP release from the heart.
Why it matters
Doctors use BNP levels to assess heart failure. If therapeutic cooling independently raises BNP, clinicians need to know this to avoid misinterpreting elevated BNP as a sign of worsening heart function in cooled patients.
The finding also adds to our understanding of how natriuretic peptides respond to temperature, which is relevant to the emerging research on cold exposure and metabolism.
The numbers in context
21 patients; BNP >5-fold increase (log 1.98→2.63, P<0.01); diastolic PAP decreased; SVI unchanged; ANP minimal change
How the study worked
This was an observational study of 21 patients who underwent therapeutic hypothermia after cardiac arrest. Researchers measured plasma BNP and ANP levels along with hemodynamic parameters including pulmonary artery pressure and stroke volume index during the cooling period.
Who was studied
Post-cardiac-arrest patients undergoing therapeutic hypothermia (human)
What this study cannot tell us
This was a small observational study with only 21 patients. There was no control group of cardiac arrest patients who were not cooled.
The patients were critically ill after cardiac arrest, so other factors beyond temperature could have influenced BNP levels. The mechanism linking cold to BNP release was not directly tested.
How to read the evidence
Moderate evidence from a small (n=21) observational study. Clear BNP elevation documented but no control group of non-cooled patients.
When this study was published
Published in 2020. Targeted temperature management protocols continue to evolve in post-cardiac arrest care.
The bigger picture
Doctors routinely use BNP to assess heart failure severity. If therapeutic cooling independently raises BNP, clinicians could misinterpret elevated levels as worsening heart function and make incorrect treatment decisions. This finding has direct bedside implications.
Questions still open
- What mechanism causes hypothermia to trigger BNP release?
- Should BNP interpretation be adjusted during therapeutic cooling protocols?
- Does the BNP rise serve a protective function during cooling?
Common questions
What is BNP and why does it matter?
Why is this finding important for cardiac arrest patients?
Read the original research
Therapeutic hypothermia after cardiac arrest increases the plasma level of B-type natriuretic peptide.
Scientific reports, 10(1), 15545
Citation
Kashiwagi, Yusuke; Komukai, Kimiaki; Kimura, Haruka; Okuyama, Toraaki; Maehara, Tomoki; Fukushima, Keisuke; Kamba, Takahito; Oki, Yoshitsugu; Shirasaki, Keisuke; Kubota, Takeyuki; Miyanaga, Satoru; Nagoshi, Tomohisa; Yoshimura, Michihiro. (2020). Therapeutic hypothermia after cardiac arrest increases the plasma level of B-type natriuretic peptide.. Scientific reports, 10(1), 15545. https://doi.org/10.1038/s41598-020-72703-2