Does diaphragm ultrasound improve the rapid shallow breathing index accuracy for predicting the success of weaning from mechanical ventilation?

BACKGROUND: This prospective study investigated whether taking into account diaphragmatic excursion (DE) measured by ultrasonography would improve the performance of the rapid shallow breathing index (RSBI) to predict extubation success or failure. OBJECTIVES: The aim of the study was to compare the new composite index named the rapid shallow diaphragmatic index (RSDI), and the RSBI measured during a spontaneous breathing trial regarding their ability to predict the need for re-intubation at 72 h. METHODS: One hundred mechanically ventilated patients underwent daily 30-min spontaneous breathing trials (SBTs) under pressure support ventilation of 6 cm H2O and end-expiratory pressure of 0 cm H2O until the SBT was considered successful and followed by extubation. The performances of RSBI (respiratory rate/tidal volume) and of the ratio RSBI/DE measured at 5 and 25 min of the successful SBT were compared in terms of area under the receiver operating characteristics curve (AUC), for predicting extubation success at 72 h. As secondary analysis, extubation and weaning success at 7 d were also considered. As exploratory analyses, predictive indices incorporating both clinical characteristics, the DE, and ultrasound diaphragm thickening fraction (DTF) were investigated. RESULTS: RSBI and RSBI/DE showed AUCs with 95% confidence intervals consistently extending below 0.50, either at the 5th (0.55 [0.36-0.74] and 0.55 [0.34-0.75], respectively) or at the 25th minute of SBT (0.49 [0.27-0.71] and 0.50 [0.29-0.68], respectively) for predicting weaning success at 72 h or at 7 d (5th min: 0.53 [0.37-0.70] and 0.54 [0.37-0.70], respectively; 25th min: 0.54 [0.37-0.71] and 0.55 [0.39-0.71], respectively). An exploratory index incorporating the accessory respiratory muscle activity, DE, DTF, and respiratory rate at 5th min of SBT showed AUCs for predicting extubation success at 7 d in the 78 patients with DTF measurement (0.77 [0.64-0.90]) that were significantly higher than that of the RSBI (P = 0.017) and RSBI/DE (P < 0.001) in the same respective populations. CONCLUSIONS: The RSBI and the ratio RSBI/DE failed to predict weaning success when measured during an SBT performed under minimal pressure support. Predictive indices incorporating ultrasound DE and DTF may merit further investigation.

Muscle weakness, functional capacities and recovery for COVID-19 ICU survivors.

BACKGROUND: Few studies have evaluated muscle strength in COVID-19 ICU survivors. We aimed to report the incidence of limb and respiratory muscle weakness in COVID-19 ICU survivors. METHOD: We performed a cross sectional study in two ICU tertiary Hospital Settings. COVID-19 ICU survivors were screened and respiratory and limb muscle strength were measured at the time of extubation. An ICU mobility scale was performed at ICU discharge and walking capacity was self-evaluated by patients 30 days after weaning from mechanical ventilation. RESULTS: Twenty-three patients were included. Sixteen (69%) had limb muscle weakness and 6 (26%) had overlap limb and respiratory muscle weakness. Amount of physiotherapy was not associated with muscle strength. 44% of patients with limb weakness were unable to walk 100 m 30 days after weaning. CONCLUSION: The large majority of COVID-19 ICU survivors developed ICU acquired limb muscle weakness. 44% of patients with limb weakness still had severely limited function one-month post weaning.

Cough Peak Flow Assessment Without Disconnection From the ICU Ventilator in Mechanically Ventilated Patients.

BACKGROUND: Because ICU ventilators incorporate flow velocity measurement, cough peak expiratory flow (CPF) can be assessed without disconnecting the patient from the ICU ventilator. Our goal was to estimate the correlation between CPF obtained with the built-in ventilator flow meter (ventilator CPF) and CPF obtained with an electronic portable handheld peak flow meter connected to the endotracheal tube. METHODS: Cooperative mechanically ventilated patients who entered the weaning process and who were ventilated with pressure support < 15 cm H2O and PEEP < 9 cm H2O were eligible for the study. Their CPF measurements obtained on the extubation day were kept for analysis. RESULTS: We analyzed CPF obtained in 61 subjects. The mean ± SD value of ventilator CPF and peak flow meter CPF were 72.6 ± 27.5 L/min and 31.1 ± 13.4 L/min. The Pearson correlation coefficient was 0.63 (95% CI 0.45-0.76), P < .001. The ventilator CPF had an area under the receiver operating characteristic curve of 0.84 (95% CI 0.75-0.93) to predict a peak flow meter CPF < 35 L/min. Neither ventilator CPF nor peak flow meter CPF differed significantly between subjects who were or were not re-intubated within 72 h (n = 5) and failed to predict re-intubation at 72 h (area under the receiver operating characteristic curve of 0.64 [95% CI 0.46-0.82] and 0.47 [95% CI 0.22-0.74]). CONCLUSIONS: CPF measurements using a built-in ventilator flow meter were feasible in routine practice with cooperative ICU subjects who were intubated and correlated with CPF assessed by an electronic portable peak flow meter.