PT  - JOURNAL ARTICLE
AU  - Knowles, Thomas P
AU  - Mullin, Rory A
AU  - Hunter, Jefferson A
AU  - Douce, Herbert F
TI  - Effects of Syringe Material, Sample Storage Time, and Temperature on Blood Gases and Oxygen Saturation in Arterialized Human Blood Samples
DP  - 2006 Jul 01
TA  - Respiratory Care
PG  - 732--736
VI  - 51
IP  - 7
4099  - http://rc.rcjournal.com/content/51/7/732.short
4100  - http://rc.rcjournal.com/content/51/7/732.full
AB  - BACKGROUND: The practice of on-ice storage of arterial-blood samples in plastic syringes for delayed analysis continues, and the effects of storage time and temperature on the measurement of blood-oxygen-saturation values (SaO2) have not been adequately described. OBJECTIVE: To determine the effects of syringe material, storage time, and storage temperature on normal arterialized blood gas and SaO2 values. METHODS: We used a temperature-controlled extracorporeal circuit to “arterialize” 500 mL of fresh, whole human blood at 37°C, and we used certified calibration gases of 12% O2 and 5% CO2 to produce normal blood-gas values. From that arterialized blood we took 90 samples and randomly assigned them to 6 groups, until there were 15 samples in each group. The groups were (1) plastic syringe, analyzed immediately, (2) plastic syringe, stored 30 min at 0-4°C, (3) plastic syringe, stored 30 min at 22°C, (4) glass syringe, analyzed immediately, (5) glass syringe, stored 30 min at 0-4°C, and (6) glass syringe, stored 30 min at 22°C. RESULTS: Compared to the samples that were analyzed immediately, the PO2 of the samples stored in plastic syringes for 30 min at 22°C and at 0–4°C was significantly higher, with a clinically important magnitude of 11.9-13.7 mm Hg. The PCO2 of blood stored in glass for 30 min at 0-4°C was significantly lower, although the magnitude of the difference (1.5 mm Hg) was not clinically important. There were no statistically significant differences in pH or oxygen saturation among the 6 groups. CONCLUSION: For accurate arterial-blood-gas results, samples drawn in plastic syringes should be analyzed immediately. If the analysis is going to be delayed, the samples should be drawn and stored in glass.