BACKGROUND: This study evaluated the feasibility of blood gas analysis and electrolyte measurements during emergency transport prior to hospital admission. RESULTS: A portable, battery-powered blood analyzer was used on patients in life threatening conditions to determine pH, pCO2, pO2, sodium, potassium and ionized calcium. Arterial blood was used for blood gas analysis and electrolyte measurements. Venous blood was used for electrolyte measurement alone. During the observation period of 4 months, 32 analyses were attempted on 25 patients. Eleven measurements (34%) could not be performed due to technical failure. Overall, 25 samples taken from 21 patients were evaluated. The emergency physicians (all anesthesiologists) considered the knowledge of blood gases and/or electrolytes to be helpful in 72% of cases. This knowledge led to immediate therapeutic consequences in 52% of all cases. After a short training and familiarization session the handling of the device was found to be problem free. CONCLUSIONS: We concluded that knowledge of the patients' pH, pCO2 and pO2 in life threatening situations yields more objective information about oxygenation, carbon dioxide and acid-base regulation than pulse oximetry and/or capnometry alone. Additionally, it enables physicians to correct severe hypokalemia or hypocalcemia in cases of cardiac failure or malignant arrhythmia.