The effect of time and temperature on arterialblood gas parameters in the patients after heart surgery

The time interval between arterial blood sampling and analysis may lead to some changes in the composition of blood gases due to ongoing anaerobic and aerobic reactions. The aim of this study was to determine the effects of time lag and ambient temperature on parameters of arterial blood gas in patients after open heart surgery admitted to Kurdkuy hospital, located in Golestan Province, Iran, in 2011. In this study samples were collected in glass tubes and kept in ice or kept in room temperature the stability of the blood gas parameters (Pao2, Pco2, pH, Hco3) for 61 samples were measured and compared at 5, 15,30 and 60 minutes after sampling. Parametric and non-parametric tests were used to analyze the data. SPSS version 16 software was used and P<0.05 was considered significant. Pao2 concentration in the samples kept in ice were significantly different from the samples in room temperature (103.86 vs. 97.48). While PacO2 did not change over time for the samples on ice, the PacO2 decreased over time for the samples in room temperature. Hco3 changes in both groups were not significant. According to our findings, the time lag and temperature shifts can affect blood gas parameters. It is necessary to consider time lag and temperature when analyzing arterial blood gases.