ORIGINAL ARTICLE

Hypoalbuminaemia in critically ill children: incidence, prognosis, and influence on the anion gap

A Durward, A Mayer, S Skellett, D Taylor, S Hanna, S M Tibby, I A Murdoch

Paediatric Intensive Care Unit, Guy’s Hospital, London, UK

Correspondence to:
Correspondence to:
Dr A Durward, Paediatric Intensive Care Unit, Floor Guy’s Tower Block, Guy’s Hospital, St Thomas Street, London SE1 9RT, UK;
adurward{at}doctors.org.uk

Aims: Hypoalbuminaemia has significance in adult critical illness as an independent predictor of mortality. In addition, the anion gap is predominantly due to the negative charge of albumin, thus hypoalbuminaemia may lead to its underestimation. We examine this phenomenon in critically ill children, documenting the incidence, early evolution, and prognosis of hypoalbuminaemia (<33 g/l), and quantify its influence on the anion gap.

Methods: Prospective descriptive study of 134 critically ill children in the paediatric intensive care unit (ICU). Paired arterial blood samples were taken at ICU admission and 24 hours later, from which blood gases, electrolytes, and albumin were measured. The anion gap (including potassium) was calculated and then corrected for albumin using Figge’s formula.

Results: The incidence of admission hypoalbuminaemia was 57%, increasing to 76% at 24 hours. Neither admission hypoalbuminaemia, nor extreme hypoalbuminaemia (<20 g/l) predicted mortality; however, there was an association with increased median ICU stay (4.9 v 3.6 days). After correction for albumin the incidence of a raised anion gap (>18 mEq/l) increased from 28% to 44% in all samples (n = 263); this discrepancy was more pronounced in the 103 samples with metabolic acidosis (38% v 73%). Correction produced an average increase in the anion gap of 2.7 mEq/l (mean bias), with limits of agreement of ±3.7 mEq/l.

Conclusion: Admission hypoalbuminaemia is common in critical illness, but is not an independent predictor of mortality. However, failure to correct the anion gap for albumin may underestimate the true anion gap, producing error in the interpretation of acid-base abnormalities. This may have treatment implications.

Keywords: albumin; anion gap; metabolic acidosis; mortality

Abbreviations: AG, anion gap; ICU, intensive care unit; PICU, paediatric intensive care unit; PIM, paediatric index of mortality score; ROC, receiver operating characteristic

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

• Morris, I, McCallion, N, El-Khuffash, A, Molloy, E J (2008). Serum albumin and mortality in very low birth weight infants. Arch. Dis. Child. Fetal Neonatal Ed. 93: F310-F312 [Abstract] [Full Text]  
• Horowitz, I. N., Tai, K. (2007). Hypoalbuminemia in Critically Ill Children. Arch Pediatr Adolesc Med 161: 1048-1052 [Abstract] [Full Text]  
• Gomez, J. L., Gunnerson, K. J., Song, M., Li, J., Kellum, J. A. (2007). Effects of Hypercapnia on BP in Hypoalbuminemic and Nagase Analbuminemic Rats. Chest 131: 1295-1300 [Abstract] [Full Text]  
• Christ-Crain, M., Jutla, S., Widmer, I., Couppis, O., Konig, C., Pargger, H., Puder, J., Edwards, R., Muller, B., Grossman, A. B. (2007). Measurement of Serum Free Cortisol Shows Discordant Responsivity to Stress and Dynamic Evaluation. J. Clin. Endocrinol. Metab. 92: 1729-1735 [Abstract] [Full Text]  
• Hatherill, M, Salie, S, Waggie, Z, Lawrenson, J, Hewitson, J, Reynolds, L, Argent, A (2005). Hyperchloraemic metabolic acidosis following open cardiac surgery. Arch. Dis. Child. 90: 1288-1292 [Abstract] [Full Text]  
• Hopfer, S. M., Nadeau, F. L., Sundra, M., Makowski, G. S. (2004). Effect of Protein on Hemoglobin and Hematocrit Assays with a Conductivity-Based Point-of-Care Testing Device: Comparison with Optical Methods. Annals of Clinical & Laboratory Science 34: 75-82 [Abstract] [Full Text]