The effect of time from last food intake on arterial blood gases: Implication on reference values

Abstract

Arterial blood gas parameters were analyzed in forty-nine healthy persons (31 males, 18 females) to detemine reference values fo these parameters and their relation to the time from last food intake to arterial puncture (T). The mean ± standard deviation of arterial oxygen pressure, arterial carbon dioxide pressure and pH at core body temperature were 84.4±7.0 mmHg (Male: 83.0±6.5, Female: 86.7±73), 37.7±2.8 mmHg (Male: 38.5±2.7, Female: 36.2±2.4) respectively 7.41±0.02 (Male: 7.41±0.02 Female: 7.42±0.03). the mean PCO2 was lower in comparison with most of the studies at sea level. The difference between males and females was significant in PCO2 and PH (P=0.004, P=0.02 respectively) but in was not significant in PO2 (P=0.07). The PCO2 and pH had no statistically significant relatioship with age (P=0.42, P=0.25 respectively). The relationship between Po2 with age, PCO2 and T was significant (P=0.02, P=0.017, and P=0.019 respectively). The best linear predictive equation was: Po2= 1.28 AO2-29.4 for T<10hours Þ AO2 =0.21 (Baro.47) –(1+0.02T) PCO2 for T >10hours Þ AO2 = 0.21(Baro-47) – (1.2PCO2