Impact of sex on use of low tidal volume ventilation in invasively ventilated ICU patients—A mediation analysis using two observational cohorts

Background Studies in patients receiving invasive ventilation show important differences in use of low tidal volume (VT) ventilation (LTVV) between females and males. The aims of this study were to describe temporal changes in VT and to determine what factors drive the sex difference in use of LTVV. Methods and findings This is a posthoc analysis of 2 large longitudinal projects in 59 ICUs in the United States, the ‘Medical information Mart for Intensive Care III’ (MIMIC III) and the ‘eICU Collaborative Research DataBase’. The proportion of patients under LTVV (median VT < 8 ml/kg PBW), was the primary outcome. Mediation analysis, a method to dissect total effect into direct and indirect effects, was used to understand which factors drive the sex difference. We included 3614 (44%) females and 4593 (56%) males. Median VT declined over the years, but with a persistent difference between females (from median 10.2 (9.1 to 11.4) to 8.2 (7.5 to 9.1) ml/kg PBW) vs. males (from median 9.2 [IQR 8.2 to 10.1] to 7.3 [IQR 6.6 to 8.0] ml/kg PBW) (P < .001). In females versus males, use of LTVV increased from 5 to 50% versus from 12 to 78% (difference, –27% [–29% to –25%]; P < .001). The sex difference was mainly driven by patients’ body height and actual body weight (adjusted average causal mediation effect, –30% [–33% to –27%]; P < .001, and 4 [3% to 4%]; P < .001). Conclusions While LTVV is increasingly used in females and males, females continue to receive LTVV less often than males. The sex difference is mainly driven by patients’ body height and actual body weight, and not necessarily by sex. Use of LTVV in females could improve by paying more attention to a correct calculation of VT, i.e., using the correct body height.

Reflections

The music Tudor made in the 1980s is difficult to understand. On the surface, it appears that he returned to the use of amplified physical objects, particularly through his partnership with Jackie Monnier. Beneath the positive appearance, however, he was pursuing an almost inaudible “negative music” based on virtually silent noises included in his past recordings extracted by using a noise gate in reverse mode. These two parallel courses intertwine in his subsequent collaboration with Monnier using radars and ultrasonic transceivers to detect the movement of kite-like volatiles reflecting the otherwise invisible movement of wind, initially conceived as an attempt to simulate the unfinished island project. These endeavors show Tudor exploring the virtual nature of silence through technology, which brings back to mind Cage’s infamous 4'33" that Tudor premiered more than thirty years before, as well as Antonin Artaud’s conception of “Virtual Reality” which first entered the English language through Tudor’s involvement. What appears at the intersection of these parallel meandering channels is the status of the actual body which processes the distinction between the virtual and the actual, a fragile instrument that at the time was beginning to fail on Tudor’s end.

Ideal Body Weight-Based Dosing of Rabbit Antithymocyte Globulin for Cost Minimization in Kidney Transplantation

Introduction: Contemporary dosing strategies for rabbit anti-thymocyte globulin (rATG) in kidney transplantation aim to reduce cumulative exposure, minimizing long-term adverse events. The use of ideal body weight-based dosing has been trialed, however concern for increased rejection post-transplant exists due to lower doses of rATG. Research Questions: The primary aim of this study was to compare rejection rates between rATG dosing protocols using actual body weight and ideal body weight and secondarily to evaluate cost savings following protocol implementation. Design: This was a retrospective study surrounding implementation of an ideal body weight-based dosing protocol for rATG. We compared 75 kidney transplant recipients in whom rATG was dosed based on actual body weight (pre-protocol group) to 64 in whom dosing was based on ideal body weight (post-protocol group), following a nine-month washout. Results: The mean cumulative rATG dose in the pre-protocol group was 6.3 mg/kg of actual body weight. When ideal body weight was used in the post-protocol group, the mean dose was 4.5 mg/kg of actual body weight. The rejection rate was 18.7% pre-protocol and 23.4% postprotocol, which did not represent a statistically significant difference (p = 0.491). The actual annual cost savings after protocol implementation exceeded $162,000, approximately $2,500 per patient. Conclusion: Results suggest ideal body weight-based dosing of rATG may reduce exposure and cost, without significantly impacting the risk of rejection in kidney transplant recipients. More studies are needed to confirm these findings.

Modified sensory feedback enhances the sense of agency during continuous body movements in virtual reality

The sense of agency refers to the feeling of control over one’s own actions, and through them, the external events. This study examined the effect of modified visual feedback on the sense of agency over one’s body movements using virtual reality in healthy individuals whose motor control was disturbed. Participants moved a virtual object using their right hand to trace a trajectory (Experiment 1) or a leading target (Experiment 2). Their motor control was disturbed by a delay in visual feedback (Experiment 1) or a 1-kg weight attached to their wrist (Experiment 2). In the offset conditions, the virtual object was presented at the median point between the desired position and the participants’ actual hand position. In both experiments, participants reported improved sense of agency in the offset condition compared to the aligned condition where the visual feedback reflected their actual body movements, despite their motion being less precise in the offset condition. The results show that sense of agency can be enhanced by modifying feedback to motor tasks according to the goal of the task, even when visual feedback is discrepant from the actual body movements. The present study sheds light on the possibility of artificially enhancing body agency to improve voluntary motor control.

Self-perception of Body Weight and Physical Activity with its Relationship to Actual Body Weight among Students in a Medical College: An Analytical Cross-sectional Study

Introduction: Obesity and sedentary life style are becoming more prevalent among the student generation. Every human being has a very good insight about the outlook. But many are not able to maintain what they perceive. During this survey, the students get a vivid picture of their real body weight and their perception of their body structure. Aim: To compare the self-perceived body weight with actual body weight among medical students and to analyse the perceptions and practice of medical student’s related to physical activity. Materials and Methods: This analytical cross-sectional study included 400 medical students. Self-perceived body image was assessed using Silhouette matching technique. Students represented the figure how they currently look (Feel) and how they actually wanted to look (Ideal). The Feel minus Ideal Discrepancy (FID) score was noted. Actual body weight and height were measured. Body Mass Index (BMI) was calculated using the Quetelet formula- weight(Kg)/height(metres)2. Perceptions and practice of physical activity were assessed using Exercise Benefits/Barrier Scale (EBBS). Comparison of perceived and actual body weight was done by Student’s Independent t-test and Pearson correlation test using Statistical Package for the Social Sciences (SPSS) version 17.0. Results: The actual BMI and perceived BMI showed strong positive correlation (r= 0.726; p=0.0001). Males had high exercise benefit scores (92) when compared with females (86) (p=0.0002). The students had high total score (benefit score plus barrier score); males had 127 and females had 124 (p=0.003) and high benefit/barrier ratio. Conclusion: Actual BMI and self-perceived BMI were well correlated indicating participant’s awareness of their body image. Male participants were more actively involved in physical activity and more concerned about maintaining their body weight. All students had higher benefit scores which is a favourable sign towards a healthy and active physical life.