SERUM-ALBUMIN AND COLLOID OSMOTIC-PRESSURE IN SURVIVORS AND NONSURVIVORS OF PROLONGED CRITICAL ILLNESS

We retrospectively compared the changes in serum albumin concentration and colloid osmotic pressure between survivors and nonsurvivors of pr olonged (greater than or equal to 7 days) critical illness over a 2-ye ar period from 1. July 1995. All patients had serum albumin measured d aily, and colloid osmotic pressure measured 5 days a week, throughout their ICU admission. They received crystalloid and colloid infusions a s well as parenteral or enteral feeding. Infusions of albumin were not used to treat hypoalbuminaemia. One hundred and forty-five patients w ere included, 66 nonsurvivors and 79 survivors. Nonsurvivors were sign ificantly older than survivors [mean (95% CI): 58 (3.8) and 49 (4.1) y ears, respectively] and had a greater risk of death [mean (95% CI): 0. 44 (0.06) and 0.28 (0.05); p < 0.05]. There was no significant differe nce in gender, APACHE II score [mean (95% CI): 22 (2.7) (nonsurvivors) ; 18 (2.3) (survivors)] or length of stay [median (interquartile range ): 14 (9-27) days (nonsurvivors); 15 (9-26) days (survivors)]. There w as no difference between the two groups in the absolute minimum serum albumin concentrations reached, the time to reach that minimum or the minimum in the first 7 days. However, nonsurvivors had a significantly lower mean serum albumin concentration: [mean (95% CI): 15.7 (5.1) g. l(-1) compared with 18.3 (4.6) g.l(-1) in survivors; p < 0.05]. They a lso had a lower recovery mean (the weighted mean after the minimum val ue): [mean (95% CI): 13.3 (5.1) g.l(-1) (nonsurvivors) and 18.6 (5.3) g.l(-1) (survivors); p < 0.01]. Analysis of colloid osmotic pressure r esults showed no difference between the groups in mean, minimum or rec overy mean. Regression analysis of mean colloid osmotic pressure and a lbumin revealed that albumin only contributed 17% of the colloid osmot ic pressure in these patients. The similar decrease in albumin in nons urvivors and survivors may reflect the acute inflammatory response and /or haemodilution. However, survivors showed an ability to increase se rum albumin concentrations, possibly owing to resumption of synthesis. The colloid osmotic pressure varied little between or within either g roup of patients, possibly because of the use of artificial colloids. There was no relationship between death and colloid osmotic pressure.