On-site determination of breath alcohol in emergency care patients

ON-SITE DETERMINATION OF BREATH ALCOHOL
IN EMERGENCY CARE PATIENTS
Annika Kaisdotter Andersson1, Bertil Hök1, Åsa Muntlin Athlin2, 3, Lia Lundin3, Urban Säfwenberg3
Hök Instrument AB, Västerås, Sweden. 2Department of Public Health and Caring Sciences/Health services research, Uppsala University, Sweden.
3
Department of Emergency Care, Uppsala University Hospital, Sweden.
1
INTRODUCTION
Many patients seeking emergency care are under the influence of alcohol, which complicates the medical assessment. There are also numerous common medical conditions
for which the patient may be falsely believed to suffer from alcohol intoxication.
According to our estimations, the outcome in terms of mortality and remaining injury
of approximately 2000 Swedish emergency care patients annually would be strongly
improved if fast and simple on-site breath alcohol determination is done.
State-of-the-art alcometers require coopera­
tion from the patient and cannot provide
quality assurance of the breath sample.
The clinical requirements on an alco­meter are
challenging with respect to measurement
accuracy, specificity for ethanol, a small
apparatus dead-space, fast response time,
robustness, and user-friendliness.
Figure 1. The concept of the future hand-held alcometer.
A hand-held instrument based on Non-Dispersive Infra Red (NDIR) spectroscopy for reliable
determination of breath alcohol also in non-cooperative patients is under development,
Fig. 1. With simultaneous measurement of the expired CO2 and through correlation of the
ethanol signal to the respiratory cycle, the user is given feedback regarding the quality of
the breath sample, from the display.
Estimated end‐exp. breath alcohol concentration [mg/l]
1.2
1
0.8
0.6
0.4
0.2
0
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
Blood alcohol concentration [mg/g]
In addition, the concentration of CO2 can be
used to compensate for the shallow expirations and eventual mixing with dead-space
or ambient air. Both these aspects contribute to improve the reliability of the breath
alcohol analysis. Fig. 2. shows results from
the first clinical tests, in which CO2 has been
used for estimation of the end-expiratory
breath alcohol concentration.
Figure 2. The relationship between the end-expiratory breath
alcohol concentration and the blood alcohol concentration.
CONCLUSION
Simple, fast and reliable determination of the breath alcohol is likely to facilitate the medical
assessment of many of the patients seeking emergency care. Prototypes of a more user
friendly alcometer, enabling more reliable measurements also in non-cooperative patients,
have been designed and fabricated. In addition, the first clinical evaluations have started.