Off-line breath acetone analysis in critical illness

Area of Science:

• Critical Care Medicine
• Biochemistry
• Analytical Chemistry

Background:

• Metabolic stress monitoring is crucial in Intensive Care Units (ICUs).
• Breath acetone analysis offers a potential non-invasive method for assessing metabolic status.
• Previous research has not extensively explored breath acetone in critical illness over extended periods.

Purpose of the Study:

• To investigate the relationship between breath and blood acetone concentrations in critically ill patients.
• To analyze changes in breath acetone levels over time and correlate them with clinical parameters.
• To evaluate the utility of breath acetone as a surrogate marker in critical care.

Main Methods:

• Consecutive patients in a mixed ICU requiring mechanical ventilation and insulin therapy for stress hyperglycemia were recruited.
• End-tidal breath samples were collected daily and analyzed using selected ion flow tube mass spectrometry (SIFT-MS).
• Breath acetone concentrations were correlated with arterial acetone and beta-hydroxybutyrate levels.

Main Results:

• A significant correlation was observed between breath acetone and arterial acetone (rs = 0.64, p < 0.0001) and arterial beta-hydroxybutyrate (rs = 0.52, p < 0.0001).
• Breath acetone concentrations showed a trend towards reduction over the monitoring period (up to 8 days).
• Changes in breath acetone over time mirrored changes in arterial acetone concentrations.

Conclusions:

• Breath acetone concentration can serve as a reliable surrogate for arterial acetone concentration in ICU patients.
• This non-invasive method may aid in future modulation of insulin therapy and nutritional support in critical illness.
• Further research could establish breath acetone monitoring for metabolic stress in ICUs.