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Trauma: N. B. Foss and H. Kehlet Hidden blood loss after surgery for hip fracture J Bone Joint Surg Br 2006; 88-B: 1053-1059 [Abstract] [Full text] [PDF]

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Hidden blood loss after surgery for hip fracture

Lalit Sharma, Vijay Kumar, Rajesh Malhotra   (20 October 2006)

Hidden blood loss after surgery for hip fracture 20 October 2006
Lalit Sharma, Orthopaedic surgeon Department of Orthopaedics, All India Institute of Medical Sciences, New Delhi, India, Vijay Kumar, Rajesh Malhotra Send letter to journal: Re: Hidden blood loss after surgery for hip fracture drlalit76{at}hotmail.com Lalit Sharma, et al.	Sir, We read this article with interest and we congratulate the authors on their excellent work. In the study, the level of haemoglobin at the time of admission was corrected by a factor of 0.9 in all patients, assuming dehydration of 10% in all patients. Although dehydration is common, it is not a universal finding in all patients and is influenced most frequently by the interval between the time of injury and admission to hospital. A patient admitted two to three hours after trauma would not be dehydrated to the same degree as one with a two-day-old trauma. We would like to know what the usual delay was in admission in the authors' practice, and also how a figure of 10% dehydration was calculated or assumed? The study has not excluded the patients with medical diseases such as renal insufficiency, unstable angina, and severe coronary artery disease, etc. These diseases are common in the study age group and can influence the intravascular volume of the patient. Similarly, the study does not comment on patients with acute post-operative infection, which can also significantly affect fluid and electrolyte homeostasis. This study has used haemoglobin balance to measure hidden blood loss, but this does not take into account the hemolysis and simultaneous erythropoiesis. The rate of hemolysis can vary in these patients and can be particularly high as allogenic RBC are transfused to most patients. Thus, hemolysis can significantly affect the haemoglobin values, rendering this method vulnerable to error. Although we agree with the authors that in most patients following hip surgery, actual loss of blood is more than the apparent loss, we do feel that the method of haemoglobin balance to assess hidden blood loss is not very accurate, particularly in the elderly where compounding diseases influencing intravascular volume are common, and when allogenic RBCs are transfused. L. Sharma, Orthopaedic Surgeon, V. Kumar, R. Malhotra, Department of Orthopaedics, All India Institute of Medical Sciences, New Delhi, India.