Clinical implications of using non-invasive haemoglobin monitoring for red blood cell transfusion decision in hip arthroplasty.

INTRODUCTION: The decision to transfuse red blood cells requires accurate haemoglobin concentration values. In this study, we evaluated if continuous non-invasive haemoglobin (SpHb) measurement could substitute laboratory determined haemoglobin (LabHb) in patients undergoing elective hip replacement. As secondary objective, we analyzed the trend of the difference between techniques. MATERIALS/METHODS: LabHb measurements were done using an automated analyser and SpHb measurements were acquired using Radical-7®. In randomly selected patients undergoing hip replacement, whenever blood was collected for LabHb, concomitant SpHb was recorded. Correlation, bias and accuracy of SpHb were calculated in comparison with LabHb. RESULTS: 108 paired measurements were obtained from 43 patients. The Pearson R of the correlation between SpHb and LabHb was 0.7 (p < 0.001). Bland-Altman test revealed a bias of 1 ± 1.4 g dL-1, meaning Lab Hb was recurrently higher than SpHb. Limits of agreement were [-1.7; 3.8]. Considering RBC transfusion threshold of 8 g dL-1, we found that in two situations transfusion decision would differ based on the measurement considered. Trending ability of SpHb study showed a significant difference between preoperative and postoperative LabHb-SpHb. DISCUSSION: There was a good correlation between SpHb and LabHb, while bias and limits of agreement were higher than those in literature. There was a limited trending ability of SpHb during the perioperative period. Despite this, using SpHb instead of LabHb for decision making regarding transfusion would only change the decision in 1.9 % of our cases. Our findings suggest that this device could be used as a reference but cannot replace venous puncture as gold standard.

Incidence of postoperative residual neuromuscular blockade in the postanaesthesia care unit: an observational multicentre study in Portugal.

CONTEXT: Residual neuromuscular blockade still presents despite the use of intermediate duration muscle relaxants and is a risk factor for postoperative morbidity. OBJECTIVE: To determine the incidence of incomplete postoperative neuromuscular recovery from anaesthesia in a postanaesthesia care unit. DESIGN: Multicentre observational study. SETTING: Public Portuguese hospitals. PATIENTS: Adult patients scheduled for elective surgery requiring general anaesthesia with neuromuscular blocking agents. MAIN OUTCOME MEASURES: An independent anaesthesiologist measured neuromuscular transmission by the TOF-Watch SX acceleromyograph. Train-of-four ratios at least 0.9 and less than 0.9 were assessed as complete and incomplete neuromuscular recovery following general anaesthesia, respectively. RESULTS: The study population consisted of 350 patients [134 men and 216 women, mean (SD) age 54.3 (15.9) years]. Ninety-one patients had a train-of-four ratio less than 0.9 on arrival in the postanaesthesia care unit, an incidence of residual neuromuscular blockade of 26% [95% confidence interval (CI) 21 to 31%]. The most frequent neuromuscular blockers were rocuronium (44.2%) and cisatracurium (32%). A neuromuscular block reversal agent was used in 66.6% of the patients (neostigmine in 97%). The incidence of residual neuromuscular blockade in patients receiving reversal agents was 30% (95% CI 25 to 37%). There were no statistically significant differences in the occurrence of residual blockade relating to the neuromuscular blocker used, although higher percentages were observed for cisatracurium (32.4%) and vecuronium (32%) compared with atracurium (23.6%) and rocuronium (20.8%). Incomplete neuromuscular recovery was significantly more frequent among patients who had received a reversal agent (30.5 vs. 17.1%, P = 0.01). Incomplete neuromuscular recovery was more frequent in patients given propofol than in those exposed to sevoflurane (26.2 vs. 14.3%). CONCLUSION: The incidence of incomplete neuromuscular recovery of 26% confirms that it is relatively frequent in the postoperative period and calls attention to the dimension of this problem in Portugal.