Background Pain management is important for ensuring early mobilization after hip arthroplasty; however, the optimal components remain controversial. Recently, the quadratus lumborum block has been proposed as an analgesic option. The current study tested the hypothesis that the posterior quadratus lumborum block combined with multimodal analgesia decreases morphine consumption after hip arthroplasty. Methods This study was a prospective, randomized, double-blind, placebo-controlled trial. Before general anesthesia, 100 participating patients scheduled for elective total hip arthroplasty were randomly allocated to receive a 30-ml injection posterior to the quadratus lumborum muscle with either 0.33% ropivacaine (n = 50) or normal saline (n = 50). For all patients, multimodal analgesia included systematic administration of acetaminophen, ketoprofen, and a morphine intravenous patient-controlled analgesia. The primary outcome was total intravenous morphine consumption in the first 24 h. Secondary outcomes recorded intraoperative sufentanil consumption; morphine consumption in the postanesthesia care unit; pain scores at extubation and at 2, 6, 12, and 24 h; motor blockade; time to first standing and ambulation; hospital length of stay; and adverse events. Results There was no significant difference in the 24-h total morphine consumption (ropivacaine group, median [interquartile range], 13 [7 to 21] versus saline group, 16 [9 to 21] mg; median difference, −1.5; 95% CI, −5 to 2; P = 0.337). Pain scores were not different between the groups (β = −0.4; 95% CI, −0.9 to 0.2; P = 0.199). There was no statistical difference between the two groups in intraoperative sufentanil consumption, morphine consumption in the postanesthesia care unit, motor blockade, times to first standing (median difference, 0.83 h; 95% CI, −1.7 to 3.4; P = 0.690) and ambulation (median difference, −1.85 h; 95% CI, −4.5 to 0.8; P = 0.173), hospital length of stay, and adverse events. Conclusions After elective hip arthroplasty, neither morphine consumption nor pain scores were reduced by the addition of a posterior quadratus lumborum block to a multimodal analgesia regimen. Editor’s Perspective What We Already Know about This Topic What This Article Tells Us That Is New

Impact of the research: Although bilateral phrenic nerve stimulation did not increase the proportion of successful weaning from mechanical ventilation compared to the standard of care, it resulted in substantial improvements in inspiratory pressure generation capacity without major safety issues. In the absence of previous clinical data, these findings suggest that diaphragm pacing could be effective in mitigating diaphragm dysfunction in patients difficult to wean from mechanical ventilation. Author contributions:The academic authors (MD, MGDA, TS) wrote the first draft of the manuscript and verified the underlying data. All authors critically reviewed and approved the manuscript and are accountable its accuracy and integrity. Dr Martin Dres had full access to all the data in the study and takes full responsibility for the integrity of the data and the accuracy of the data analysis. Teresa Nelson conducted and is responsible for the data analysis. Support:The study was funded by Lungpacer Medical Inc, PA, USA.

Background: Muscle weakness following critical illness is the consequence of loss of muscle mass and alteration of muscle quality. It is associated with long-term disability. Ultrasonography is a reliable tool to quantify muscle mass, but studies that evaluate muscle quality at the critically ill bedside are lacking. Shear wave ultrasound elastography (SWE) provides spatial representation of soft tissue stiffness and measures of muscle quality. The reliability and reproducibility of SWE in critically ill patients has never been evaluated.Methods: Two operators tested in healthy controls and in critically ill patients the intra-and inter-operator reliability of the SWE using transversal and longitudinal views of the diaphragm and limb muscles. Reliability was calculated using the intra-class correlation coefficient and a bootstrap sampling method assessed their consistency. Results: We collected 560 images. Longitudinal views of the diaphragm (ICC 0.83 [0.50-0.94]), the biceps brachii (ICC 0.88 [0.67-0.96]) and the rectus femoris (ICC 0.76 [0.34-0.91]) were the most reliable views in a training set of healthy controls. Intra-class correlation coefficient for inter-operator reproducibility and intra-operator reliability was above 0.9 for all muscles in a validation set of healthy controls. In critically ill patients, inter-operator reproducibility and intra-operator 1 and 2 reliability ICCs were respectively 0.92 [0.71-0.98], 0.93 [0.82-0.98] and 0.92 [0.81-0.98] for the diaphragm; 0.96 [0.86-0.99], 0.98 [0.94-0.99] and 0.99 [0.96-1] for the biceps brachii and 0.91 [0.51-0.98], 0.97 [0.93-0.99] and 0. 99 [0.97-1] for the rectus femoris. The probability to reach intra-class correlation coefficient greater than 0.8 in a 10,000 bootstrap sampling for inter-operator reproducibility was respectively 81%, 84% and 78% for the diaphragm, the biceps brachii and the rectus femoris respectively.Conclusions: SWE is a reliable technique to evaluate limb muscles and the diaphragm in both healthy controls and in critically ill patients. Trial registration: The study was registered (ClinicalTrial NCT03550222).