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Background: Results of arterial blood gas analysis can be biased by pre-analytical factors, such as time interval before analysis, temperature during storage and syringe type.
Objectives: To investigate the effects of samples storage temperature and time delay on blood gases, bicarbonate and PH results in human arterial blood samples.
Patients and Methods: 2.5 mL arterial blood samples were drawn from 45 patients via an indwelling Intraarterial catheter. Each sample was divided into five equal samples and stored in multipurpose tuberculin plastic syringes. Blood gas analysis was performed on one of five samples as soon as possible. Four other samples were divided into two groups stored at 22°C and 0°C. Blood gas analyses were repeated at 30 and 60 minutes after sampling.
Results: PaO2 of the samples stored at 0°C was increased significantly after 60 minutes (P = 0.007). The PaCO2 of the samples kept for 30 and 60 minutes at 22°C was significantly higher than primary result (P = 0.04, P < 0.001). In samples stored at 22°C, pH decreased significantly after 30 and 60 minutes (P = 0.017, P = 0.001). There were no significant differences in other results of samples stored at 0°C or 22°C after 30 or 60 minutes.
Conclusions: In samples stored in plastic syringes, overestimation of PaO2 levels should be noted if samples cooled before analysis. In samples stored in plastic syringes, it is not necessary to store samples in iced water when analysis delayed up to one hour.
Keywords: Blood Gas Analysis; Bicarbonate; Temperature
1. Background
Arterial blood gas (ABG) analysis is important in the evaluation of clinical condition of critically ill patients. Results of ABG analysis can be biased by pre-analytical factors, such as time interval before analysis, temperature during storage and the syringe type. However, the acceptable temperature and delay between the time of collection and arterial blood gas analysis remain unknown (1). Based on limited studies, delay in the analysis can decrease arterial oxygen partial pressure (PaO2) and increase arterial carbon dioxide partial pressure (PaCO2) because of the cell metabolism (2, 3). Ice preservation is recommended; however, there is no reason to keep arterial blood in ice if the blood gas analysis is performed within 30 minutes (4).
Although most studies indicate that glass syringes...