High-flow nasal cannula oxygen therapy and noninvasive ventilation for preventing extubation failure during weaning from mechanical ventilation assessed by lung ultrasound score: A single-center randomized study.

BACKGROUND: We sought to demonstrate the superiority of a targeted therapy strategy involving high-flow nasal cannula oxygen (HFNCO2) therapy and noninvasive ventilation (NIV) using lung ultrasound score (LUS) in comparison with standard care among patients in the intensive care unit (ICU) who undergo successful weaning to decrease the incidence of extubation failure at both 48 hours and seven days. METHODS: During the study period, 98 patients were enrolled in the study, including 49 in the control group and 49 in the treatment group. Patients in the control group and patients with an LUS score <14 points (at low risk of extubation failure) in the treatment group were extubated and received standard preventive care without NIV or HFNCO2. Patients with an LUS score ≥14 points (at high risk of extubation failure) in the treatment group were extubated with a second review of the therapeutic optimization to identify and address any persisting risk factors for postextubation respiratory distress; patients received HFNCO2 therapy combined with sessions of preventive NIV (4-8 hours per day for 4-8 sessions total) for the first 48 hours after extubation. RESULTS: In the control group, 13 patients had the LUS scores ≥14 points, while 36 patients had scores <14 points. In the treatment group, 16 patients had the LUS scores ≥14 points, while 33 patients had scores <14 points. Among patients with the LUS score ≥14 points, the extubation failure rate within 48 hours was 30.8% in the control group and 12.5% in the treatment group, constituting a statistically significant difference (P<0.05). Conversely, among patients with an LUS score <14 points, 13.9% in the control group and 9.1% in the treatment group experienced extubation failure (P=0.61). The length of ICU stay (9.4±3.1 days vs. 7.2±2.4 days) was significantly different and the re-intubation rate (at 48 hours: 18.4% vs. 10.2%; seven days: 22.4% vs. 12.2%) significantly varied between the two groups (P<0.05). There was no significant difference in the 28-day mortality rate (6.1% vs. 8.2%) between the control and treatment groups. CONCLUSIONS: Among high-risk adults being weaned from mechanical ventilation and assessed by LUS, the NIV+HFNCO2 protocol does not lessen the mortality rate but reduce the length of ICU stay, the rate of extubation failure at both 48 hours and seven days.

Value of lung ultrasound score for evaluation of blast lung injury in goats.

PURPOSE: To establish a severe blast lung injury model of goats and investigate the feasibility of lung ultrasonic score in the evaluation of blast lung injury. METHODS: Twenty female healthy goats were randomly divided into three groups by different driving pressures: 4.0 MPa group (n = 4), 4.5 MPa group (n = 12) and 5.0 MPa group (n = 4). The severe blast lung injury model of goats was established using a BST-I bio-shock tube. Vital signs (respiration, heart rate and blood pressure), lung ultrasound score (LUS), PO2/FiO2 and extravascular lung water (EVLW) were measured before injury (0 h) and at 0.5 h, 3 h, 6 h, 9 h, 12 h after injury. Computed tomography scan was performed before injury (0 h) and at 12 h after injury for dynamic monitoring of blast lung injury and measurement of lung volume. The correlation of LUS with PaO2/FiO2, EVLW, and lung injury ratio (lesion volume/total lung volume*100%) was analyzed. All animals were sacrificed at 12 h after injury for gross observation of lung injury and histopathological examination. Statistical analysis was performed by the SPSS 22.0 software. The measurement data were expressed as mean ± standard deviation. The means of two samples were compared using independent-sample t-test. Pearson correlation analysis was conducted. RESULTS: (1) At 12 h after injury, the mortality of goats was 0, 41.67% and 100% in the 4.0 Mpa, 4.5 MPa and 5.0 MPa groups, respectively; the area of pulmonary hemorrhage was 20.00% ± 13.14% in the 4.0 Mpa group and 42.14% ± 15.33% in the 4.5 MPa group. A severe lung shock injury model was established under the driving pressure of 4.5 MPa. (2) The respiratory rate, heart rate, LUS and EVLW were significantly increased, while PaO2/FiO2 was significantly reduced immediately after injury, and then they gradually recovered and became stabilized at 3 h after injury. (3) LUS was positively correlated with EVLW (3 h: r = 0.597, 6 h: r = 0.698, 9 h: r = 0.729; p < 0.05) and lung injury ratio (12 h: r = 0.884, p < 0.05), negatively correlated with PaO2/FiO2 (3 h: r = -0.871, 6 h: r = -0.637, 9 h: r = -0.658; p < 0.05). CONCLUSION: We established a severe blast lung injury model of goats using the BST-I bio-shock tube under the driving pressure of 4.5 MPa and confirmed that ultrasound can be used for quick evaluation and dynamic monitoring of blast lung injury.

Use of a Doppler-Based Pulsatility Index to Evaluate Cerebral Hemodynamics in Neurocritical Patients After Hemicraniectomy.

OBJECTIVES: As a noninvasive method for evaluation of cerebral hemodynamics, the correct interpretation of transcranial Doppler or transcranial imaging (TCI) data remains a major challenge. We explored how to interpret the pulsatility index (PI) derived via TCI during evaluations of cerebral hemodynamics in posthemicraniectomy patients. METHODS: We included patients who underwent invasive arterial pressure and intracranial pressure (ICP) monitoring and simultaneous TCI examinations after hemicraniectomy. We classified the PI of the middle cerebral artery (MCA) into ipsilateral (craniectomy side) and contralateral (opposite side) and analyzed both data sets. The statistical analysis was performed by the Bland-Altman approach, by calculating intraclass correlation coefficients and Spearman correlations, and by drawing receiver operating characteristic curves. Pulsatility index probability charts were created for ICPs exceeding 20, 25, and 30 mm Hg and cerebral perfusion pressures (CPPs) lower than 70, 60, and 50 mm Hg; we thus explored defined ICP and CPP values. RESULTS: The ipsilateral and contralateral MCA PI data differed. Only the ipsilateral MCA PI showed a weak correlation with ICP (r = 0.378; P < .001). The receiver operating characteristic curve analysis revealed limited diagnostic utility of bilateral MCA PIs for ICP and CPP assessments. An extremely elevated MCA PI indicated that patients were at high risk of a dangerous ICP elevation or CPP reduction. However, MCA PI values within the normal range did not effectively rule out an ICP of 20 mm Hg or higher but effectively eliminated a CPP lower than 50 mm Hg. CONCLUSIONS: In posthemicraniectomy patients, the Doppler-based MCA PI value was ineffectively for quantitative ICP and CPP evaluations but a useful index for assessment of cerebral hemodynamics in terms of the probability of an ICP elevation or a CPP reduction.