The role of routine blood tests in the evaluation of postoperative bleeding in bariatric patients
Aims: The aim of this study is to investigate the role of routine blood tests in evaluating and identifying post-operative haemorrhage in patients undergoing bariatric procedures. Methods: This was a retrospective study covering a period between 01/03/2009 to 31/05/ 2013. Data were obtained from the bariatric database maintained by one of the Royal Derby Hospital Bariatric surgeon. Epidemiological data, type of procedure and pre- and day one post- operative blood test results were recorded. There were no exclusion criteria. Statistical analysis was done using chi-square test. Results: A total of 367 consecutive patients (258 female) were included. 298 gastric bypasses, 53 sleeve gastrectomies and 16 revisions were performed. A total of 83 patients had 101 complications in the post-operative period ranging from six months to two years. Four patients had significant post-operative bleeding that required further surgical intervention. These were identified with a combination of observations (tachycardia and hypotension), physical examination, blood test results and imaging (in 3 cases). Analysis of pre and post-operative blood tests revealed a statistically significant relationship between haemorrhage and a drop in haemoglobin of more than 20 g/L (p<0.001), an increase in white cell count by 4x109/L (p<0.05), an increase in the haematocrit by a factor of 15 % (p<0.05) - which cannot be explained by the infusion of routine intravenous fluids alone and an increase in the creatine by 10 mumol/L (p<0.05). Conclusions: Physical signs and examination are valuable when assessing patients in order to establish any post-operative complications. Para-clinical investigations (routine bloods and imaging investigations) offer a more holistic approach and can sometimes reveal a significant complication that might otherwise not be obvious at first instance. The cut-off points proposed above can hopefully offer a useful guide and alert to the physicians that perform the initial assessment in such patients.