BMJ  2006;333:551 (9 September), doi:10.1136/bmj.333.7567.551-a

Letter

Early intervention in acute renal failure

Evidence of inadequate intravenous fluid treatment in UK hospitals

EDITOR—Bennett-Jones emphasises the importance of prompt administration of intravenous fluids for early intervention in acute renal failure.¹ Determining the appropriate rate of fluid administration must include an estimate of the degree of intravascular volume depletion at the start of treatment, with most aggressive volume expansion targeted at patients with the greatest deficits. To determine whether this simple principle is followed in practice, we audited intravenous fluid prescriptions for 114 consecutive acute surgical admissions to three UK centres (one teaching hospital and two district general hospitals).

A raised ratio of blood urea to creatinine is commonly used as a quantitative reference standard for the diagnosis of hypovolaemia,² and similar rises may be seen in patients with reduced effective intravascular volume secondary to sepsis.³ We therefore compared the initial rate of intravenous fluid administration for each patient with their urea:creatinine ratio on admission. We excluded from the analysis patients with chronic renal failure or upper gastrointestinal haemorrhage, or who were taking drugs known to affect this ratio.

Across all admissions, the volume of fluid prescribed over the first hour of treatment ranged from 83 ml to 1250 ml. The degree of correlation between rate of administration and urea:creatinine ratio was low, with a correlation coefficient for the complete data set of only 0.23 (95% confidence interval: 0.05 to 0.40). This indicates that just 5.3% of the variation in rate of fluid administration can be explained by an association with urea:creatinine ratio (and hence degree of intravascular volume depletion).

The most likely explanation for this finding is a failure by the admitting doctors to appropriately diagnose and treat hypovolaemia. In UK hospitals, fluid prescription is typically left to the most junior members of medical and surgical teams, among whom inadequate knowledge is common.⁴ Training and practice clearly need improving, and courses such as ALERT (acute life-threatening events—recognition and treatment) may be a good start.⁵

St Thomas' Hospital, London SE1 7EH nickmatheson{at}yahoo.com

John Radcliffe Hospital, Oxford OX3 9DU

Great Western Hospital, Swindon SN3 6BB

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We thank Nicola Alder, medical statistician at the Centre for Statistics in Medicine, Oxford, for her help with data analysis.

Competing interests: None declared.

References

1. Bennett-Jones DN. Early intervention in acute renal failure. BMJ 2006;333: 406-7. (26 August.)[Free Full Text]
2. McGee S, Abernethy WB, Simel DL. Is this patient hypovolaemic? JAMA 1999;281: 1022-9.[Abstract/Free Full Text]
3. Robinson BE, Weber H. Dehydration despite drinking: beyond the BUN/creatinine ratio. J Am Med Dir Assoc 2004;5(2 suppl): S68-71.[CrossRef]
4. Lobo DN, Dube MG, Neal KR, Simpson J, Rowlands BJ, Allison SP. Problems with solutions: drowning in the brine of an inadequate knowledge base. Clin Nutrition 2001;20: 125-30.[CrossRef][ISI][Medline]
5. Smith GB, Osgood VM, Crane S, ALERT Course Development Group. ALERT—a multiprofessional training course in the care of the acutely ill adult patient. Resuscitation 2002;52: 281-6.[CrossRef][ISI][Medline]

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