Neuromuscular sonography detects changes in muscle echotexture and nerve diameter in ICU patients within 24 h

Purpose During an ICU stay, changes in muscles and nerves occur that is accessible via neuromuscular sonography. Methods 17 patients recruited from the neurological and neurosurgical ICU (six women; 66 ± 3 years) and 7 healthy controls (three women, 75 ± 3 years) were included. Muscle sonography (rectus abdominis, biceps, rectus femoris and tibialis anterior muscles) using gray-scale values (GSVs), and nerve ultrasound (peroneal, tibial and sural nerves) analyzing the cross-sectional area (CSA) were performed on days 1 (t1), 3 (t2), 5 (t3), 8 (t4), and 16 (t5) after admission. Results Time course analysis revealed that GSVs were significantly higher within the patient group for all of the investigated muscles (rectus abdominis: F = 7.536; p = 0.011; biceps: F = 14.761; p = 0.001; rectus femoris: F = 9.455; p = 0.005; tibialis anterior: F = 7.282; p = 0.012). The higher GSVs were already visible at t1 or, at the latest, at t2 (tibialis anterior muscles). CSA was enlarged in all of the investigated nerves in the patient group (peroneal nerve: F = 7.129; p = 0.014; tibial nerve: F = 28.976, p < 0.001; sural nerve: F = 13.051; p = 0.001). The changes were visible very early (tibial nerve: t1; peroneal nerve: t2). The CSA of the motor nerves showed an association with the ventilation time and days within the ICU (t1 through t4; p < 0.05). Discussion We detected very early changes in the muscles and nerves of ICU-patients. Nerve CSA might be a useful parameter to identify patients who are at risk for difficult weaning. Therefore our observations might be severity signs of neuromuscular suffering for the most severe patients.

Critical illness-related corticosteroid insufficiency during difficult weaning from mechanical ventilation

Background Critical illness-related corticosteroid insufficiency (CIRCI) is common during critical illness and is usually associated with poor outcomes, as prolonged duration of mechanical ventilation (MV) and higher mortality. CIRCI may alter cardiac and vascular functions. Weaning-induced pulmonary oedema (WiPO) is a major mechanism of weaning failure. The aim of this study was to evaluate the role of CIRCI in patients with difficult ventilator weaning and its possible relation with WiPO. Methods This is a prospective study conducted in the intensive care of a university hospital in France. Patients under MV for more than 24 h, meeting weaning criteria and having failed the first spontaneous breathing trial (SBT) underwent a corticotropin stimulation test, with assessment of total blood cortisol levels immediately before (T0) 0.25 mg iv of tetracosactrin and 30 and 60 min afterward. Δmax was defined as the difference between the maximal value after the test and T0. CIRCI was defined as T0 < 10 μg/dL (276 nmol/L) and/or Δmax < 9 μg/dL (248 nmol/L) and inadequate adrenal reserve as Δmax < 9 μg/dL. Biomarkers (natriuretic peptide and protidemia) sampling and echocardiograms were performed during the second SBT and were used to diagnose WiPO, which was defined according to two definitions (one liberal and one conservative) derived from recent publications on the topic. Successful extubation was defined as patient alive without reintubation 7 days after extubation. A competing risk analysis was used to assess extubation failure and mortality. Results Seventy-six consecutive patients (63 ± 14 years; 49 men) with difficult weaning were enrolled. CIRCI and inadequate adrenal reserve occurred in 25 (33%) and 17 (22%) patients, respectively. The probability of successful extubation was significantly decreased in patients with CIRCI or inadequate adrenal reserve, as compared to their counterparts, and this association persisted after adjustment on severity (SOFA score at first SBT). WiPO occurred in 44 (58%) and 8 (11%) patients, according to the liberal and conservative definition, respectively. WiPO was not associated with CIRCI nor with inadequate adrenal reserve. Conclusion CIRCI was common during difficult weaning and was associated with its prolongation. We did not find a significant association between CIRCI and WiPO.

Does Neurally Adjusted Ventilatory Assist Compared to Pressure Support Ventilation Decrease Patient Ventilator Asynchrony?

BACKGROUND: Patient-mechanical ventilator (MV) asynchrony despite optimal adjustment of MV parameters is a common problem that is partly associated with difficult weaning of MV. Neurally adjusted ventilatory assist (NAVA) is a mode of proportional ventilation that count on diaphragmatic activity (measured by special esophageal probe and expressed as diaphragm electrical [Edi]) to provide proportional support to patient effort which differs from one breath to another according to Edi signal. AIM: The purpose of this trial is to determine the impact of NAVA compared to pressure support ventilation (PSV) mode in decreasing patient-MV asynchrony and hemodynamic effect in patients on MV with expected difficult weaning. MATERIALS AND METHODS: This prospective interventional trial was conducted on 30 critically ill on MV with expected difficult weaning. First, patients were put on PSV mode for 24 h. Then, patients were put on NAVA mode (for weaning) for the next 24 h. The incidence of different types of asynchrony in both modes was investigated. RESULTS: NAVA mode significantly reduced the asynchrony index when compared to PSV (1.1 ± 0.39% vs. 2.8 ± 1.1, respectively, p < 0.001), P/F ratio was significantly higher during NAVA (250 in NAVA vs. 210 in PSV, p < 0.001), heart rate, and mean arterial blood pressure were significantly reduced during NAVA (p < 0.001 and 0.015, respectively). CONCLUSIONS: Compared to PSV, NAVA-reduced patient-MV asynchrony significantly and increased the P/F ratio significantly with better hemodynamics.

CRITERIA FOR SUCCESSFUL WEANING FROM MECHANICAL VENTILATION IN CHILDREN

The aim of the research was to establish criteria for successful weaning from mechanical ventilation in children based on analysis of Paediatric rapid shallow breathing index, maximum amplitude of diaphragm movements, diaphragm thickening fraction and pressure support (PS), which ensure minimal respiratory muscle load, level of consciousness which ensure minimal respiratory muscle load and presence of cough and swallowing reflexes and previous unsuccessful attempts of weaning. Investigated problem: there is no consensus on the basic physiological parameters for successful extubation that have to be achieved during weaning from mechanical ventilation in children due to variability in size and degree of maturity of lungs and patients’ comorbidities. It leads to the lack of clinical justification for the routine practice of weaning in children. The main scientific results: We have established a list of causes of unsuccessful weaning depending on the function of the diaphragm in children with different types of respiratory failure. We have clarified and supplemented the list of reasons for unsuccessful weaning from mechanical ventilation depending on nutritional status and level of serum electrolytes in children. We have identified and supplemented the list of reasons for unsuccessful weaning from mechanical ventilation depending on the disorders of neurological status in children. We have supplemented the algorithm for predicting difficult weaning from mechanical ventilation in children. The area of practical use of the research results: the obtained results have to increase the rate of successful weaning in children with acute respiratory failure in pediatric intensive care units.