Evaluation of point-of-care haemoglobin measuring devices: a comparison of Radical-7™ pulse co-oximetry, HemoCue(®) and laboratory haemoglobin measurements in obstetric patients*.

We prospectively compared two point-of-care haemoglobin concentration measuring devices with laboratory measurements to determine their accuracy in women undergoing caesarean section delivery. The two devices were the Masimo Rainbow SET(®) Radical -7™ pulse co-oximeter and the HemoCue(®) HB 201+, which is a cuvette-type system that uses photometry. Co-oximeter readings and HemoCue measurements were taken before and after surgery, and compared with laboratory measurements of haemoglobin concentration taken at the same time. We analysed data from 137 patients using Bland-Altman plots. Limits of agreement for co-oximeter readings were -2.19 to 3.41 g.dl(-1) and for the HemoCue were -1.52 to 1.79 g.dl(-1) . The bias (mean difference) for the co-oximeter was -0.61 g.dl(-1) (95% CI 0.36 to -0.86) and for the HemoCue was 0.13 g.dl(-1) (95% CI -0.015 to 0.28). [corrected] Overall, 110/274 (40%) co-oximeter readings were within 1 g.dl(-1) of laboratory values compared with 247/274 (90%) HemoCue measurements (p < 0.001 for difference). The co-oximeter gave lower readings and was less accurate than the HemoCue system when compared with laboratory measurements.

Efficacy of augmentation of epidural analgesia for Caesarean section.

BACKGROUND: Extension of a labour epidural for Caesarean delivery is thought to be successful in most cases and avoids the use of general anaesthesia. However, most previous studies that have estimated the failure rate of pre-existing epidural catheters were performed in small numbers of patients. METHODS: Therefore, we undertook to retrospectively measure the failure rate of indwelling epidural catheters in a large number of patients. RESULTS: The anaesthetic team was available at all times and was permanently led by a senior anaesthetist specialized in obstetrics. Extension was performed using lidocaine 2% with epinephrine (mean 18 (SD 6) ml), combined in most patients with sufentanil (9 (2.2) microg) and/or clonidine (75 microg). Among 194 consecutive extensions performed in a 1-yr period, general anaesthesia was required in five patients (2.6%) while sedation and/or i.v. analgesia were used in 27 patients (13.9%). In three cases where general anaesthesia was required, the interval between decision to incision was <10 min. No factor associated with failure could be identified. Addition of a lipophilic opioid or of clonidine did not modify the efficacy of the block (i.e. general anaesthesia or supplementation were required in a similar proportion). CONCLUSIONS: The augmentation of labour epidurals for Caesarean section using lidocaine 2% plus epinephrine is a reliable and effective technique. No factor associated with failure could be identified.