BackgroundMost patients with unilateral diaphragm paralysis (UDP) have unexplained dyspnea, exercise limitations, and reduction in inspiratory muscle capacity. We aimed to evaluate the generation of pressure in each hemidiaphragm separately and its contribution to overall inspiratory strength.MethodsTwenty-seven patients, 9 in right paralysis group (RP) and 18 in left paralysis group (LP), with forced vital capacity (FVC) < 80% pred, and 20 healthy controls (CG), with forced expiratory volume in 1 s (FEV1) > 80% pred and FVC > 80% pred, were evaluated for lung function, maximal inspiratory (MIP) and expiratory (MEP) pressure measurements, diaphragm ultrasound, and transdiaphragmatic pressure during magnetic phrenic nerve stimulation (PdiTw).ResultsRP and LP had significant inspiratory muscle weakness compared to controls, detected by MIP (− 57.4 ± 16.9 for RP; − 67.1 ± 28.5 for LP and − 103.1 ± 30.4 cmH2O for CG) and also by PdiTW (5.7 ± 4 for RP; 4.8 ± 2.3 for LP and 15.3 ± 5.7 cmH2O for CG). The PdiTw was reduced even when the non-paralyzed hemidiaphragm was stimulated, mainly due to the low contribution of gastric pressure (around 30%), regardless of whether the paralysis was in the right or left hemidiaphragm. On the other hand, in CG, esophagic and gastric pressures had similar contribution to the overall Pdi (around 50%). Comparing both paralyzed and non-paralyzed hemidiaphragms, the mobility during quiet and deep breathing, and thickness at functional residual capacity (FRC) and total lung capacity (TLC), were significantly reduced in paralyzed hemidiaphragm. In addition, thickness fraction was extremely diminished when contrasted with the non-paralyzed hemidiaphragm.ConclusionsIn symptomatic patients with UDP, global inspiratory strength is reduced not only due to weakness in the paralyzed hemidiaphragm but also to impairment in the pressure generated by the non-paralyzed hemidiaphragm.

A respiratory rate of 17 breaths/min is the parameter with the greatest accuracy for diagnosing overassistance. Respiratory rates of less than or equal to 12 or greater than or equal to 30 are useful clinical references to confirm or exclude pressure support overassistance.

Background Usefulness of noninvasive ventilation (NIV) in weaning patients with non-hypercapnic hypoxemic acute respiratory failure (hARF) is unclear. The study aims to assess in patients with non-hypercapnic hARF, the efficacy of NIV after early extubation, compared to standard weaning. Methods In this individual patient data meta-analysis, we searched EMBASE, Medline and Cochrane Central Register of Controlled Trials to identify potentially eligible randomized controlled trials published from database inception to October 2020. To be eligible, studies had to include patients treated with NIV after early extubation and compared to conventional weaning in adult non-hypercapnic hARF patients. Anonymized individual patient data from eligible studies were provided by study investigators. Using one-step and two-step meta-analysis models we tested the difference in total days spent on invasive ventilation. Results We screened 1605 records. Six studies were included in quantitative synthesis. Overall, 459 participants (mean [SD] age, 62 [15] years; 269 [59%] males) recovering from hARF were included in the analysis (233 in the intervention group and 226 controls). Participants receiving NIV had a shorter duration of invasive mechanical ventilation compared to control group (mean difference, − 3.43; 95% CI − 5.17 to − 1.69 days, p < 0.001), a shorter duration of total days spent on mechanical ventilation (mean difference, − 2.04; 95% CI − 3.82 to − 0.27 days, p = 0.024), a reduced risk of ventilatory associated pneumonia (odds ratio, 0.24; 95% CI 0.08 to 0.71, p = 0.014), a reduction of time spent in ICU (time ratio, 0.81; 95% CI 0.68 to 0.96, p = 0.015) and in-hospital (time ratio, 0.81; 95% CI 0.69 to 0.95, p = 0.010), with no difference in ICU mortality. Conclusions Although primary studies are limited, using an individual patient data metanalysis approach, NIV after early extubation appears useful in reducing total days spent on invasive mechanical ventilation. Trial registration The protocol was registered to PROSPERO database on 12/06/2019 and available at PROSPERO website inserting the study code i.e., CRD42019133837.

No abstract