title: Estimation of blood haemoglobin concentration using the HemoCue during caesarean section: the effect of sampling site.
abstract: BACKGROUND
  Haemoglobin concentration measured using the HemoCue is accurate for capillary and venous/arterial blood, provided the recommended sampling method is strictly observed. Analysis of blood, particularly of capillary samples, using the HemoCue is useful during caesarean section. The toe might be preferred to the thumb since it is numb during neuraxial anaesthesia, but whether sampling at either site is accurate in this situation, given the cardiovascular effects of anaesthesia and pregnancy, is not known. We aimed to compare haemoglobin values measured in venous and capillary samples (toe and thumb) during caesarean section under neuraxial anaesthesia.
  
  
  METHODS
  Fifty healthy women having caesarean section under spinal or combined spinal-epidural anaesthesia were included. At the end of surgery, the great toe and thumb (non-i.v. fluid side) were lanced as recommended for a HemoCue reading. A venous blood sample (non-i.v. fluid side) was also taken and sent for formal laboratory measurement and tested with the HemoCue. Bland-Altman analysis was applied to the haemoglobin values.
  
  
  RESULTS
  Bias (mean difference) and precision +/- 2 SD were respectively 0.2 +/-1.6 for laboratory vs. toe, 0.1 +/-1.8 for laboratory vs. thumb, and 0.2 +/-1.6 laboratory vs. venous.
  
  
  CONCLUSIONS
  Our results suggest that in terms of accuracy, the two sites are equally suitable for use during caesarean section under neuraxial anaesthesia.
authors: Magill Department of Anaesthesia, Intensive Care and Pain Management, Chelsea and Westminster Hospital, London, UK. narichards@gmail.com
authors: N A
authors: NA
authors: Richards
authors: H
authors: H
authors: Boyce
authors: S M
authors: SM
authors: Yentis
mesh_terms: D000328:Adult; D002196:Capillaries / Q000378:metabolism; D002585:Cesarean Section; D005260:Female; D006452:Hemoglobinometry / Q000295:instrumentation*; D006454:Hemoglobins / Q000032:analysis*; D006801:Humans; D019095:Point-of-Care Systems; D011247:Pregnancy; D015203:Reproducibility of Results
chemical_list: D006454:Hemoglobins